Advanced Energy Design Guide For K-12 School ... - ashrae.org

AEDG-K12 90% Review Draft 1

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Advanced Energy Design Guide For K-12 School Buildings

Final Review Draft

90% Complete

7/09/07

American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

The American Institute of Architects

Illuminating Engineering Society of North America

U.S. Green Building Council

United States Department of Energy

Copyright 2007 ASHRAE, 1791 Tullie Circle NE, Atlanta, GA 30329. All rights reserved.

This is a draft document intended only for internal use by the Society, including review and discussion. It may not be copied or redistributed in paper or digital form or posted on an unsecured Web site without prior written permission from ASHRAE.

ASHRAE has compiled this draft document with care, but ASHRAE has not investigated, and ASHRAE expressly disclaims any duty to investigate any product, service, process, procedure, design, or the like that may be described herein. The appearance of any technical data or editorial material in this draft document does not constitute endorsement, warranty, or guaranty by ASHRAE of any product, service, process, procedure, design, or the like, and ASHRAE expressly disclaims same. ASHRAE does not warrant that the information in this draft document is free of errors, and ASHRAE does not necessarily agree with any statement or opinion in this draft document.


This is an ASHRAE Design Guide. Design Guides are developed under ASHRAE’s Special Publication procedures and are not consensus documents. This document is an application manual that provides voluntary recommendations for consideration in achieving greater levels of energy savings relative to minimum standards. This publication was developed under the auspices of ASHRAE Special Project 111.

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ADVANCED ENERGY DESIGN GUIDE K-12 SCHOOL BUILDINGS PROJECT COMMITTEE

Paul Torcellini – Chair

Merle McBride Jim Benya

Vice Chair IESNA Representative

Don Colliver Leslie Davis Steering Committee Liaison IESNA Representative

Mike Nicklas Larry Schoff

AIA Representative USGBC Representative

Kathleen O’Brien Jyoti Sharma AIA Representative USGBC Representative

Charles Eley Bruce Hunn

CHPS Representative ASHRAE Staff Liaison

Bill Brenner Milton S. Goldman, M.D. NCEF / NIBS Representative ASHRAE TC 9.7 Representative

Carol Marriott John Murphy

ASHRAE SSPC 90.1 Representative SBIC Representative

Lilas Pratt ASHRAE Staff Liaison

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AEDG STEERING COMMITTEE

Don Colliver – Chair

Markku Allison John Hogan AIA Consultant (ASHRAE TC 2.8)

Terry Townsend Harry Misuriello

ASHRAE Consultant (ASHRAE TC 7.6)

Rita Harrold Jerry White IESNA Consultant (ASHRAE Std. 90.1)

Brenden Owens Dru Crawley

USGBC DOE


CONTENTS 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82

90% FINAL REVIEW DRAFT .................................................................................................................................5 ACKNOWLEDGMENTS...........................................................................................................................................6 ABBREVIATIONS AND ACRONYMS....................................................................................................................7 FOREWORD: A MESSAGE TO SCHOOL ADMINISTRATORS AND SCHOOL BOARDS .........................9

IMPROVED LEARNING ENVIRONMENT .......................................................................................................................9 REDUCED OPERATING COST......................................................................................................................................9 LOWER CONSTRUCTION COSTS/FASTER PAYBACK..................................................................................................10 ENVIRONMENTAL CURRICULUM ENHANCEMENT ....................................................................................................10 ENERGY SECURITY ..................................................................................................................................................10 WATER AS A RESOURCE...........................................................................................................................................10 GREENHOUSE GAS EMISSION REDUCTION...............................................................................................................10 ACHIEVING THE 30% ENERGY SAVINGS GOAL........................................................................................................11 A GOAL WITHIN REACH...........................................................................................................................................11

CHAPTER 1 INTRODUCTION.............................................................................................................................12 SCOPE......................................................................................................................................................................12 SCHOOL PROTOTYPES..............................................................................................................................................12 ACHIEVING 30-PERCENT ENERGY SAVINGS ............................................................................................................13 HOW TO USE THIS GUIDE.........................................................................................................................................15 REFERENCES............................................................................................................................................................15

CHAPTER 2 USING AN INTEGRATED DESIGN APPROACH TO ACHIEVE 30% SAVINGS ................18 1. PRE-DESIGN PHASE .............................................................................................................................................19 2. DESIGN PHASE.....................................................................................................................................................20 3. CONSTRUCTION ...................................................................................................................................................21 4. OCCUPANCY: EVALUATE PERFORMANCE AND TRAIN USERS ..............................................................................22

CHAPTER 3 RECOMMENDATIONS BY CLIMATE........................................................................................24 CLIMATE ZONE 1 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................27 CLIMATE ZONE 2 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................31 CLIMATE ZONE 3 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................35 CLIMATE ZONE 4 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................39 CLIMATE ZONE 5 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................43 CLIMATE ZONE 6 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................47 CLIMATE ZONE 7 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................51 CLIMATE ZONE 8 RECOMMENDATION TABLE FOR K-12 SCHOOLS ..........................................................................55

CHAPTER 4 CASE STUDIES .................................................................................................................................58 THIRD CREEK ELEMENTARY SCHOOL, STATESVILLE, NC .......................................................................................58 ZACH ELEMENTARY SCHOOL, FORT COLLINS, CO..................................................................................................62 ALDER CREEK MIDDLE SCHOOL, TRUCKEE, CA .....................................................................................................64


WESTWOOD ELEMENTARY SCHOOL, MINNESOTA: ..................................................................................................67 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97

THE DALLES MIDDLE SCHOOL, OREGON.................................................................................................................69 BOLINGBROOK HIGH SCHOOL, BOLINGBROOK, IL ..................................................................................................72

CHAPTER 5 HOW TO IMPLEMENT RECOMMENDATIONS .......................................................................76 ENVELOPE ...............................................................................................................................................................76 VERTICAL GLAZING ................................................................................................................................................83 LIGHTING AND DAYLIGHTING .................................................................................................................................86 HVAC...................................................................................................................................................................108 SERVICE WATER HEATING ....................................................................................................................................125 ADDITIONAL SAVINGS...........................................................................................................................................127

APPENDIX A ENVELOPE THERMAL PERFORMANCE FACTORS .........................................................136 APPENDIX B ADDITIONAL RESOURCES.......................................................................................................137 APPENDIX C COMMISSIONING AND QUALITY ASSURANCE................................................................138 APPENDIX D ENERGY EFFICIENT EQUIPMENT........................................................................................140


90% Final Review Draft 98 99

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The Advanced Energy Design Guide for K-12 School Buildings (AEDG-K12) Project Committee (PC) has completed the Final Review Draft (90%) and it is now available for peer review. It is important to understand that this draft contains information and material that are still subject to change. At this stage in the review process we are interested in your remarks regarding any errors, omissions, or inconsistencies in the specific details and recommendations that you see reflected in the draft document.

The recommendations presented in Chapter 3 for the envelope, lighting, HVAC and SWH have been specifically tailored for K-12 schools. These recommendations have been analyzed using detailed hourly simulation programs in each of the eight climate zones and the energy savings for all locations have been at least 30% better than ASHRAE Standard 90.1-1999 and in some instances greater. Chapter 4 presents case studies of buildings that are consistent with the recommendations presented in this Guide. The goal of the case studies is to focus on just the attributes that are aligned with the features of this guide and contribute towards the 30% energy savings goal. We invite the peer reviewers to suggest existing technology examples or case studies that would meet the 30% energy savings target for consideration. Chapter 5 contains specific recommendations and implementation details to achieve the 30% savings.

Note that the document will receive a comprehensive edit by the ASHRAE staff after the technical portion of the document is complete. The committee thanks you in advance for your review.


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The acknowledgments will be added upon the completion of the project.


Abbreviations and Acronyms 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173

A area - ft2

ACCA Air Conditioning Contractors of America AEDG-SR Advanced Energy Design Guide - Small Retail AFUE Annual Fuel Utilization Efficiency - dimensionless AIA American Institute of Architects ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers ASTM American Society for Testing and Materials ANSI American National Standards Institute bhp brake horsepower Btu British Thermal Unit C Thermal Conductance - Btu/(h·ft2·oF) CA Census Area CD Construction Documents CHPS Collaborative for High Performance Schools c.i. Continuous Insulation Cx Commissioning CxA Commissioning Authority cfm Cubic Feet per Minute CHPS Collaborative for High Performance Schools CM Construction Manager CMH Ceramic Metal Halide COP Coefficient of Performance - dimensionless CPE Chlorinated Polyethylene CPSE Chlorosulfonated Polyehtylene CRI Color Rendering Index CRRC Cool Roof Rating Council D Diameter - ft DL Code for Daylighting DOE United States Department of Energy DSP Daylighting Saturation Percent DX Direct Expansion Ec Efficiency, combustion - dimensionless EF Efficiency EIA Energy Information Agency Et Efficiency, thermal - dimensionless EER Energy Efficiency Ratio - Btuh/Watt EF Energy Factor EL Code for Electric Lighting EN Code for Envelope EX Code for Exterior Lighting F Slab Edge Heat Loss Coefficient per Foot of Perimeter – Btu/(h·ft·oF) FFR Daylighting Fenestration to Floor Area Ratio – dimensionless FWR Vertical Fenestration to Gross Exterior Wall area ratio - dimensionless GC General Contractor Guide Advanced Energy Design Guide – K-12 Schools HC Heat Capacity - Btu/(ft2·oF) HSPF Heating Season Performance Factor - dimensionless HV Code for HVAC Systems and Equipment HVAC Heating, Ventilating and Air-Conditioning IESNA Illuminating Engineering Society of North America in inch


IPLV Integrated Part Load Value - dimensionless 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219

kBtuh Thousands of British Thermal Units per Hour kW Kilowatt LBL Lawrence Berkeley Laboratory LED Light Emitting Diode LPD Lighting Power Density - W/ft2

N/A Not Applicable NBI New Buildings Institute NCEF National Clearinghouse for Educational Facilities NEMA National Electrical Manufacturers Association NFRC National Fenestration Rating Council NIBS National Institute of Building Sciences NREL National Energy Renewable Laboratory NZEB Net Zero-Energy Buildings O&M Operation and Maintenance OPR Owner’s Project Requirements PC Project Committee PF Projection Factor PL Code for Plug Loads ppm part per million psf pounds per square foot PV Photovoltaic PVC Polyvinyl Chloride QA Quality Assurance R Thermal Resistance - (h·ft2·oF)/Btu RPI Rensselear Polytechnic Institute SBIC Sustainable Buildings Industry Council SEER Seasonal Energy Efficiency Ratio - (h·ft2·oF)/Btu SHGC Solar Heat Gain Coefficient - dimensionless SP Special Project SSPC Standing Standards Project Committee Std. Standard SWH Service Water Heating TAB Test and Balance TC Technical Committee TPO Thermoplastic Polyolefin QA Quality Assurance U Thermal Transmittance - Btu/(h·ft2·oF) UPS Uninterruptible Power Supply USGBC U. S. Green Building Council VLT Visible Light Transmission W Watts w.c. Water Column WH Code for Water Heating Systems and Equipment


Foreword: A Message to School Administrators and School Boards

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The Advanced Energy Design Guide for K-12 Schools can help you build new schools that are 30% more energy efficient than current industry standards using ASHRAE Standard 90.1-1999 as a benchmark. This saves energy, but perhaps more importantly, it helps you achieve your school’s educational mission. Here’s how.

Improved Learning Environment Seventeen studies, some prepared by educators, reported in “Greening America’s Schools Costs and Benefits”1 show that improved indoor air quality, acoustically designed indoor environments and high performance lighting systems can produce productivity increases anywhere from just under 2% to over 25%.

There are many research studies show that daylighting can improve academic performance as much as 20%. Daylighting is also a key strategy for achieving energy savings. So what is daylighting? Daylighting uses the sun to produce high-quality lighting to a space that is glare-free and provides good quality full-spectrum lighting with little or no electrical lighting.

Modern daylighting techniques include new technologies that bring daylight deep into classrooms without glare or increased cooling loads. A well designed daylighting strategy also saves energy from not running the lights and reduces the cooling loads by not removing the heat generated by the lights.

Quality lighting systems include a combination of daylighting and energy efficient electric lighting; these systems, when properly designed are glare-free and properly directed to work areas producing less visual strain and better quality of light. Advanced, energy-efficient heating and cooling systems provide good thermal comfort and are quiet. This produces quieter, more comfortable, and more productive spaces. Various studies show that noise exposure – even modest levels of ambient noise – affects educational outcomes. The impact on learning is magnified for younger children.

Advanced, energy-efficient heating and cooling systems create cleaner, healthier indoor environments, lowering student and staff absentee rates, and improving teacher retention. This translates into higher test scores and lower staff costs. Ash Creek Intermediate School in Oregon is one of a growing number of high performance schools where students experience a significant reduction in absenteeism once moved in. At Ash Creek, the reduction was 15%.

Reduced Operating Cost Strategic upfront investments in energy efficiency have been shown to provide significant long term savings. At Durant Road Middle School in Raleigh, North Carolina the school system saves thousands of dollars annually and the initial investment was recouped within two years. The total annual energy cost in 2006 was only $1.01/ft2. Smart use of a site’s climatic resources and more efficient envelope design are keys to reducing a building’s overall energy requirements. Efficient equipment and energy management programs then help meet those requirements more cost-effectively. Because of growing water demand and shrinking aquifers, the price of water is escalating at 10% per year or greater in some areas. Saving energy

1 http://www.cap-e.com/ewebeditpro/items/O59F9819.pdf

AEDG-K12 90% Review Draft

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generally means saving water; the reverse can also be true. Lower operating costs also means less fluctuation in operational budgets because of price instabilities of energy. In many ways, purchasing energy efficiency is buying into energy futures at a known fixed cost.

Lower Construction Costs/Faster Payback Thoughtfully designed, energy-efficient schools can actually cost less to build. For example, the same building with north-south glazing would have downsized mechanical systems and, thereby, cost less than one that is oriented with east-west glazing. The heating systems at the Topham Elementary School in Langley, British Columbia requires half as much heat as the next most efficient school in its district, costs half as much to maintain, and was less expensive to install. More efficient lighting and equipment means less lighting and equipment is needed. Better insulation and daylighting mean heating and cooling units can be downsized. Some energy efficiency measures may add to a school’s construction cost, however, the savings in annual operating costs ensure a quick payback, often within a few years.

Lower construction and operating costs also signify responsible stewardship of public funds. This translates into greater community support for school construction financing whether through local district bonds or state legislative action.

Environmental Curriculum Enhancement Schools incorporating energy-efficiency and renewable energy technologies make a strong statement about the importance of protecting the environment. They also provide hands-on opportunities for students and visitors to learn about these technologies and the importance of energy conservation.

Energy Security Building an energy-conserving school reduces its vulneprice of natural gas has increased over 270% between 1to climb as part of an overall trend upward. Additionalloil is now imported. Using less energy also helps contrcountry and our local communities.

Water as a resource Water is a rapidly depleting natural resource. Though trelated energy conservation measures, water savings ressavings from low-flow fixtures, reduced water use due related energy savings from pumping and waste disposawater processing energy savings of 50-75 Btu/gallon.

Greenhouse Gas Emission Reduction Buildings are responsible for almost half (48%) of all gUnited States. Carbon Dioxide, which is produced whecontributor to green house gas emissions. As concerns school districts that reduce their consumption of fossil f

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rability to volatile energy pricing. The 994 and 2004. The cost of oil continues y, approximately 60% of United States’ ibute to a more secure future for our

his guide only deals with direct building ult in related energy savings. Water

to efficient landscaping etc. result in l. Potable water savings also result in

reenhouse gas emissions annually in the n fossil fuel is consumed, is the primary about climate change continue to grow, uels for heating, cooling, and/or


electricity can be a part of the solution. Students and their parents will appreciate this forward-thinking leadership.

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Achieving the 30% Energy Savings Goal Building a new school to meet or exceed a 30% energy savings goal is not difficult, but it does take some care. In particular, it requires selecting a design team willing and able to produce a design that meets the energy saving goals. It also requires a team that ensures that the building is constructed as designed and that the school system staff is trained to operate the building’s energy systems properly.

Design Team: To help optimize your design, reference your energy goal and this Guide in your RFQ/RFP. Ideally your prospective design team is already familiar with the Guide. Regardless, the team you select should have an established record of constructing buildings that operate with significant energy savings. Design firms that successfully coordinate among project team members, bring in building users and facilities staff for input, and use an iterative process to test design concepts are more likely to achieve the 30% goal cost-effectively.

Energy savings up to 30% can be achieved without the use of computer building energy modeling by using the prescriptive measures recommended in this guide. However, if properly performed, computer building energy modeling produces more predictable results and can help you optimize your design – the result being less upfront construction cost and energy savings that often can approach 50%. Consider the design team’s energy modeling capabilities during the architect/engineer selection process to allow for achieving even greater savings.

Commissioning Authority (also referred to as Commissioning Agent): A building can be the best possible design for achieving energy savings, but unless the building is built as designed and is operated according to the design intent, energy savings will not be achieved. A commissioning authority ensures the energy and water saving methods and devices selected by the design team are incorporated in the building plans and specifications; that everything is built and tested accordingly; and that school personnel, including those occupying the building, are provided the necessary documentation and training to properly operate the building after it is occupied. The commissioning authority can be an independent member of the design firm, the school’s facility staff, or a third-party consultant. Some prefer to use third-party consultants for this role to ensure that the work is done independently of the design team to ensure that the results are not biased.

School Personnel. It is important to train operations and maintenance personnel in proper operation of a school’s energy systems when the building is occupied. Initial training should be backed up by a strong long term commitment to maintain an informed staff, including administrative, instructional, and facilities personnel, and to fund proper upkeep over the life of the installed systems.

A Goal within Reach Saving 30% or more in energy costs is within the reach of any school district with the will do so. It is a good deal for everyone – students, teachers, administrators, and taxpayers. Join organizations including ASHRAE, the American Institute of Architects, the U.S. Green Building Council, the Illuminating Engineering Society of North America, the Sustainable Buildings Industry Council, the U.S. Department of Energy, and the National Institute of Building Sciences in the goal to save energy, save money, protect the environment, and create a more secure energy future. We look forward to hearing about your new energy efficient schools through the case study database at www.ashrae.org/aedg. 346

http://www.ashrae.org/aedg


Chapter 1 Introduction 347 348 349 350 351 352 353

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The Advanced Energy Design Guide for K-12 Schools is written to help designers of elementary, middle, and high schools achieve energy savings of at least 30 percent compared to the minimum requirements of ANSI/ASHRAE/IESNA Standard 90.1-1999, which serves as a baseline. The guide contains recommendations only and is not a code or standard. It provides a way, but not the only way, to meet the 30-percent target and build energy-efficient K-12 schools that use substantially less energy than those built to minimum energy code requirements.

The guide was developed by a project committee representing a diverse group of professionals. Guidance and support was provided through a collaboration of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the American Institute of Architects (AIA), the Illuminating Engineering Society of North America (IESNA), the U.S. Green Building Council (USGBC), and the U.S. Department of Energy (DOE). Members of the project committee came from these partner organizations, the ASHRAE Standing Standards Project Committee 90.1 (SSPC 90.1), the ASHRAE Technical Committee on Educational Facilities (TC 9.7), the Sustainable Building Industry Council (SBIC), the Collaborative for High Performance Schools Project (CHPS), and the National Clearinghouse for Educational Facilities (NCEF) at the National Institute of Building Sciences (NIBS).

The 30-percent energy savings target is the first step toward achieving net-zero energy schools; schools that, on an annual basis, draw from outside sources less or equal energy than they generate on site from renewable energy sources. For more information on net-zero energy buildings, see the references at the end of this chapter.

Other guides in this series include the Advanced Energy Design Guide for Small Office Buildings, Advanced Energy Design Guide for Warehouses, and the Advanced Energy Design Guide for Small Retail Buildings. Successor guides are planned for achieving 50- and 70-percent energy savings, with the ultimate goal of building net-zero energy buildings.

Scope This guide applies to K-12 (classified as elementary, middle and high schools) school facilities with administrative and office areas, classrooms, hallways, restrooms, gymnasiums, assembly spaces, food preparation spaces, and dedicated spaces such as media centers and science labs. It is primarily intended for new construction, but it may be equally applicable to many school renovation, remodeling and modernization projects.

Included in the guide are recommendations for the design of the building envelope, fenestration, lighting systems (including electrical lights and daylighting), HVAC systems, building automation and controls, the treatment of outside air, service water heating, electrical distribution, exterior lighting controls, plug loads, and commissioning.

The user should note that the recommendation tables do not include all of the components listed in Standard 90.1. Though this Guide focuses only on the primary energy systems within a building, the underlying energy analysis presumes that all the other components are built to the 384 criteria in Standard 90.1.385

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School Prototypes To provide a baseline for this guide, three school prototype designs with a variety of envelope, lighting, and HVAC configurations were prepared and analyzed by using hourly building simulations in eight climate zones. The designs include a 74,500 square-foot elementary school,


an 112,000 square-foot middle school, and a 205,000 square-foot high school. The space types included in each prototype designs are shown in Table 1.

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Space Types Elementary Middle High Classrooms X X X

Library X X X

Media Center X X X

Computer Lab X X X

Science Lab X X

Music X X X

Arts/Crafts X X X

Multipurpose Room X

Auditorium/Theater X

Special Ed/Resource X X X

Gymnasium X X

Auxiliary Gymnasium X

Offices X X X

Infirmary/Clinic X X X

Cafeteria X X X

Kitchen X X X

Hall Lockers X X

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Two simulations were run for each prototype, the first meeting the minimum requirements of ASHRAE Standard 90.1-1999 and the second utilizing this guide to achieve a 30-percent energy savings in all climate zones. All materials and equipment used in the simulations are commercially available from two or more manufacturers.

The energy use intensity for the school prototypes over all climates and buildings analyzed ranges from 54 kBtu/ft2 to 138 kBtu/ft2 when designed to meet ASHRAE Standard 90.1-1999. The 30-percent energy savings school prototypes range from 37 kBtu/ft2 to 80 kBtu/ft2. Complete results of the prototype school simulations are available from the U.S. Department of Energy at TBD.

Achieving 30-Percent Energy Savings Meeting the 30-percent energy savings goal is not difficult, but it requires more than doing business-as-usual. Here are the essentials.

1. Obtain school district buy-in. There must be strong buy-in from the school district’s leadership and staff. The more they know about and participate in the planning and design process, the better able they will be to help achieve the 30-percent goal after the school becomes operational. See the National Clearinghouse for Educational Facilities resource list “School Energy Savings” at www.ncef.org for information about obtaining support for building energy-efficient, high-performing schools.

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2. Assemble an experienced, innovative A/E team. Interest and experience in designing energy-efficient buildings, innovative thinking, and the ability to work together as a team are all critical to meeting the 30-percent goal by creating a school that maximizes daylighting, minimizes heating and cooling losses, , and has highly efficient lighting and HVAC systems. This process

http://www.ncef.org/


can include developing a Request for Proposal (RFP) that includes energy goals for the design team to meet.

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3. Adopt an integrated design approach. Cost-effective energy efficient design requires trade-offs among potential energy-saving features. This requires the use of an integrated approach to school design. A highly efficient lighting system, for instance, may cost more than a conventional one but because it produces less heat, the building’s cooling system can be downsized and both systems will use less energy. The greater the energy savings the more complicated the trade-offs become and the more the various disciplines on the design team must work together to determine the optimal mix of energy-saving features. Because of the many options available, the design team will have wide latitude in making energy-saving tradeoffs. This guide used an integrated approach to achieve the energy savings.

4. Consider energy modeling. This guide is designed to help achieve energy savings of 30 percent without the use of energy modeling, but energy modeling programs make evaluating energy-saving tradeoffs faster and far more precise. Although these programs have learning curves of varying difficulty, the use of energy modeling for school design is highly encouraged, and is considered necessary for achieving energy savings beyond 30 percent. See the U.S. Department of Energy’s Building Energy Software Tools Directory http://www.eere.energy.gov/buildings/tools_directory for links to current energy modeling programs. Part of the key to energy savings is using the simulations to make envelope decisions first and then evaluate heating and cooling systems options. Note that developing HVAC load calculations is not energy modeling, and is not a substitute for energy modeling.

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5. Use building commissioning. Studies verify that building systems, no matter how carefully designed, are often improperly installed or set up and do not operate as efficiently as expected. The 30-percent goal only can be achieved through “building commissioning,” a systematic process of ensuring that all building systems – envelope, lighting, HVAC, et al perform as intended. The commissioning process works because it integrates the traditionally separate functions of building design, system selection, equipment startup, system control calibration, testing, adjusting, and balancing, documentation, and staff training.

The more comprehensive the commissioning process, the greater the likelihood of energy savings. A commissioning authority should be appointed at the beginning of the project and work with the design team throughout the project. Solving problems at the design phase is more effective and less-expensive than making changes or fixes during construction. Among other things, the commissioning agent should review and validate all HVAC load calculations.

For more information on commissioning, refer to the Collaborative for High Performance Schools’ Best Practices Manual, Volume VI, Commissioning (www.chps.net); ASHRAE Guideline 1, The HVAC Commissioning Process (

450 www.ashrae.org)and NIBS Guideline 3,

Exterior Enclosure Technical Requirements for the Commissioning Process (451

www.wbdg.org). See also the NCEF resource list “School Building Commissioning” at

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6. Train building users and operations staff. Staff training can be part of the building commissioning process, but a plan must be in place to train staff for the life of the building to meet energy saving goals. The building’s designers and contractors normally are not responsible for the school after it becomes operational, so the school district must establish a continuous training program that helps building occupants and maintenance personnel maintain and operate the school for maximum energy efficiency. This training should include information about the impact of plug loads on energy consumption, and the importance of using energy efficient

http://www.eere.energy.gov/buildings/tools_directory

http://www.chps.net/

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equipment and appliances. For information on staff training, see the NCEF resource list “School Facilities Management” at

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7. Monitoring the building. To ensure that energy goals are met and continued to be met over the life of the building, a monitoring plan must be established. Even simple plans such as recording and plotting monthly utility bills can be useful in ensuring that the energy goals are met. Buildings that don’t meet the design goals often have operational issues that should be corrected.

How to Use this Guide ● Review Chapter 2 to understand how an integrated design approach is used for achieving 30-percent or more energy savings. Checklists show how to establish and maintain the energy savings target throughout the project.

● Use Chapter 3 for selecting specific energy saving measures by climate zone. This chapter provides an alternate path to having to model energy savings, because energy modeling is normally included in basic design services. These measures also can be used to earn credits for CHPS, LEED™, and other building energy rating systems.

● Review the case studies in Chapter 4 to see how the 30-percent energy savings goal has been met in schools from various climatic zones across the country.

● Use Chapter 5 to apply the energy-saving measures in Chapter 3. Its has how-to tips on best design practices, problems to avoid, and ways to achieve additional savings through the use of energy efficient appliances and other plug-in equipment.

References American Institute of Architects (AIA)

1735 New York Ave., NW

Washington, DC 20006-5292

1-800-AIA-3837 or 1-202-626-7300

http://www.aia.org/486

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American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

1791 Tullie Circle, N.E.

Atlanta, GA 30329

1-800-527-4723 or 1-404-636-8400

http://www.ashrae.org/492

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ASHRAE Standing Standards Project Committee 90.1 (SSPC 90.1)

ASHRAE Technical Committee on Educational Facilities (TC 9.7)


http://www.aia.org/

http://www.ashrae.org/


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Collaborative for High Performance Schools (CHPS)

142 Minna Street, Second Floor

San Francisco, CA 94105

1-887-642-CHPS

http://www.chps.net/500

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Illuminating Engineering Society of North America (IESNA)

120 Wall Street, Floor 17

New York, NY 10005

1-212-248-5000

http://www.iesna.org/506

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National Clearinghouse for Educational Facilities (NCEF)

1090 Vermont Ave., NW, Suite 700


1-888-552-0624 or 1-202-289-7800

http://www.edfacilities.org/512

513

514

515

516

517

National Institute of Building Sciences (NIBS)

1090 Vermont Ave., NW, Suite 700


1-202-289-7800

http://www.nibs.org/518

519

520

521

522

523

Sustainable Building Industry Council (SBIC)

1112 16th Street, NW, Suite 240

Washington, DC 20036

1-202-628-7400

http://www.sbicouncil.org/524

525

526 527

528

Torcellini, P., D. Crawley, (2006) “Understanding Zero-Energy Buildings,” ASHRAE Journal, September 2006, pp. 62-69, Atlanta, GA.

http://www.chps.net/

http://www.iesna.org/

http://www.edfacilities.org/

http://www.nibs.org/

http://www.sbicouncil.org/


Torcellini, P., Pless, S., Deru, M. Crawley, D.; (2006). Zero Energy Buildings: A Critical Look at the Definition. Paper #417, Proceedings (CD-ROM), ACEEE Summer Study on Energy Efficiency in Buildings, August 13−18, 2006, Pacific Grove, CA. National Renewable Energy Laboratory, Golden, CO. 12 pp.

529 530 531 532

http://www.nrel.gov/docs/fy06osti/39833.pdf (PDF 477 KB). 533

534

535

536

537

538

U.S. Department of Energy (USDOE)

1000 Independence Ave., SW


1-800-dial-DOE (1-800-342-5363) or 1-202-586-5000

http://www.energy.gov/539

540

541

542

543

544

U.S. Green Building Council (USGBC)

1800 Massachusetts Ave., NW, Suite 300


1-800-795-1747 or 1-202-742-3792

http://www.usgbc.org/545

546

http://www.nrel.gov/docs/fy06osti/39833.pdf

http://www.energy.gov/

http://www.usgbc.org/


Chapter 2 Using an Integrated Design Approach to Achieve 30% Savings

547 548 549 550 551 552 553 554

555 556

The integrated design process looks to minimize the building loads through appropriate building siting and increasing the thermal efficiency of the envelope. Almost always this reduces the demands for the subsystems of the building such as HVAC, plumbing, lighting, and power. Integration encourages the “right-sizing” of building systems and components which then allows reduced first and life cycle costs. Where possible, renewable energy sources (photovoltaic, solar hot water), are used along with low emission technologies.

A successful integrated design approach provides the best energy performance at the least cost and is characterized as follows:

It is resourceful. Integrated design begins with site assessment and selection. The site is an opportunity to obtain free energy resources. Daylighting can provide most lighting needs in many geographic locations passive solar heat can reduce mechanical heating loads, external overhangs can reduce cooling loads, and photovoltaic panels can reduce the amount of electricity produced by fossil fuels. Selecting the proper building orientation, form, and layout provide substantial energy savings by themselves.

557 558 559 560 561 562

It is multidisciplinary. Integrated design goes beyond the conventional practice of a kick-off meeting with the designers and their consultants. Instead, it includes the involvement of the owner, designers, technical consultants, construction manager, commissioning authority, facility staff, and end users in all phases of the project. The process requires cross disciplinary design and validation at all phases of the process.

563 564 565 566 567

It is goal-driven. A goal-setting session early in the design process can identify strategies to meet energy efficiency and other sustainable building goals in relation to the school’s mission. By including school district representatives, parents, and, when appropriate, students in this session, the likelihood of coming up with integrated, creative solutions is greatly increased. Aligning design goals with learning and including those invested in the school’s mission is key to a successful project. It is important that goals be quantifiable and measurable.

568 569 570 571 572 573

It is iterative. A goal-setting session is just the start. As the design concept takes shape, it is important to test it to determine which strategies will result in the energy performance desired while optimizing maintenance requirements and reducing life-cycle costs. Preferably, this takes the form of energy modeling at key points in the design process. It also requires time to be set aside during design reviews to discuss energy use on a system-level basis.

574 575 576 577 578

579 580 581 582 583

584 585 586 587 588

589

590

The commissioning authority is an integral part of this iterative process. The commissioning authority, who is either a member of the school district’s facility staff, an independent staff member from the design firm, or an outside consultant, validates that the energy saving goals are being met by the design documents, that the building is built as designed and that the school staff knows how to use, operate and maintain the building in order to achieve the energy saving goals.

The following presentation of an integrated process for achieving energy savings in new school buildings is valuable for designers and builders who want to augment and improve their practices so that energy efficiency is deliberately considered at each stage of the development process from project conception through building operation. For each task, the responsibility is stated in parentheses.


1. Pre-Design Phase 591 592 593 594 595

596 597 598 599 600

601 602 603 604 605 606 607 608 609

610

Adopting measurable energy goals at the beginning of the project will guide the team and provide a benchmark during the project’s life. General strategies that relate to these goals will be identified at this phase as part of the goal discussions. Strategies will be further refined and confirmed during the design phase.

Because of the nature of school buildings, goal setting should include consideration of the community context, as well as curriculum opportunities. For example, one might prioritize an energy strategy that also “teaches.” Another example identifying synergies with other community facility uses to avoid unnecessary buildings, thereby not only reducing energy use for operations but also the energy needed for materials and construction.

Emphasize goals that relate to large energy uses and can produce the most savings. Priorities are likely to vary significantly from one climate to another and may vary among schools in the same climate zone. Site conditions can impact energy performance significantly. For example, differences in building application, climate, and even orientation will impact the selection of various energy goals and strategies. Figure 2-1 shows the baseline energy use for a 74,500 ft2 elementary school in the 15 different climate zones. It demonstrates that cooling and lighting energy predominates in Climate Zone 1 (Miami), so there the goals and strategies for cooling and lighting should receive the highest priorities. Conversely, in Climate Zone 8 (Duluth), the goals and strategies for heating and lighting should receive the highest priority.

01A 2A 2B

20

40

6

8

140

3A 4B 4C 5A 5B 6A 6B 7A 8A

Site

EU

I u/

ft2 )

0

0

100

Water SystemsHeatingFans

120

Cooling

3B 3C 4A

(kB

t

Interior LightingExterior LightingInterior Equipment

611 y School Baseline End Uses Across Climate Zones 612

613

614

Figure 2-1. Elementar


Table 2.1. Energy Goivities

als in the Context of the Pre-Design Phase 615 Act Responsibilities Where to Find Information 1.1 -Select the core team

a. Designers – the project architects and engineers

b. Commissioning authority c. Construction manager

Owner

1.2 -Asses the site blic

Owner, Designer, Construction Manager a. Evaluate access to pu

transportation b. Identify on-site energy

opportunities c. Identify best building

orientation 1.3 -Define functional and

spatial requirements Owner and Designer

1.4 -Adopt energy goals Owner and Designer 1.5 -Define energy efficiency

and budget benchmarks Owner, Designer, Construction Manager, Estimator

1.6 -Prepare the design and construction schedule

Owner, Designer, Construction Manager

1.7 -Determine building -systems preferences


1.8 -Perform cost/benefit analysis for energy strategies

Owner and Designer

1.9 -Identify applicable energy code requirements

Owner and Designer

616

2. Design Phase 617 In the design phase, the project team develops energy strategies and incorporates them into 618 building plans and specifications. This will have a major impact on the overall energy 619 performance of the building as constructed. Design choices should first work to optimize on-site 620 resources, then to reduce energy loads, then to properly size systems, and finally to incorporate 621 efficient equipment. At each point, the decisions should take into account other priorities and 622 systems decisions. For example, sizing cooling systems should take into account daylighting 623 measures, glazing sizes and building orientation. 624

The commissioning authority reviews the design to validate that the project goals are being met. 625 Commissioning authority duties can also include validation of HVAC load calculations and 626 review of modeling assumptions. 627


628 629 Table 2.2. Energy Goals in the Context of the Design Phase

Activities Responsibilities Where to Find Information

2.1-Prepare diagrammatic building plans that satisfy functional program requirements

Designer

2.2-Develop specific energy strategies Owner, Designer, Construction Manager, Commissioning Authority

2.3-Develop the site plan to make best use of building orientation and daylighting strategies

Designer

2.4-Select building systems taking into account their desired energy efficiency


2.5-Develop building plans, sections, and details incorporating the above strategies

Designer

2.6-Develop architectural and lighting details; for example, lighting, fenestration, exterior sun control, taking into account their energy implications

Designer

2.7-Refine the design; for example, refine the building elevations to reflect the appropriate location and size of windows

Designer

2.8-Perform design reviews at each phase of the project to verify that the project meets functional and energy goals

Owner, Designer, Construction Manager, Commissioning Authority

2.9-Calculate building HVAC loads AND run energy models to optimize design at each design stage (schematic, design development, and construction drawings) to ensure that energy goals are being met. Use recommended loads for lighting power density from this guide

Designer

2.10-Match capacity of HVAC systems to design loads, specify equipment efficiency as recommended by this guide

Designer

2.11-Perform final coordination and integration of architectural, mechanical, and electrical systems

Designer

2.12-Prepare specifications for all systems Designer 2.13-Integrate commissioning specifications into project

manual Designer and Commissioning Authority

2.14-Prepare cost estimates at each phase of design Construction Manager, Commissioning Authority, Estimator

2.15-Review and revise final design documents Owner, Designer, Commissioning Authority

630

631 632 633 634

3. Construction Even the best design will not yield the expected energy savings if the construction plans and specifications are not correctly executed. Below are strategies that the project team can do to keep the construction process in line with energy design goals.


Table 2.3. Energy Goals in the Context of the Bidding and Construction Phase 635 Activities Responsibilities Where to Find Information 3.1-At the pre-bid conference,

emphasize energy efficiency measures and the commissioning process


3.2-At all job meetings, review energy efficiency measures and commissioning procedures


3.3-Verify that building envelope construction carefully follow the drawings and specifications

Designer, Commissioning Authority

3.4-Verify that HVAC and electrical systems meet specifications

Designer, Commissioning Authority

636

637 638 639 640 641 642 643

644 645 646 647 648 649 650 651 652 653 654 655

4. Occupancy: Evaluate Performance and Train Users Occupancy is a critical time in the process, often neglected by the project teams. Energy savings for a building are difficult to attain if the building occupants and operation and maintenance staff do not know how to use, operate and maintain the buildings. Commissioning authority should ensure timely submittals of the O&M manuals through specifications and regular reminders at construction meetings. Commissioning authority should also ensure adequate and timely training of all school personnel.

During the first year of operation the building operator should review the overall operation and performance of the building. Building systems not performing as expected should be discussed with the design and construction team and resolved during the warranty period. Over time, the building’s energy use, changes in operating hours, and the addition of energy consuming equipment should be documented by school facilities staff. This information can be used in the process of determining how well the building is performing and taking lessons back to the design table for future projects. Building performance evaluations should take place on a schedule specified in a maintenance manual provided to the owner as part of final project acceptance. On-going training of school personnel, including facilities staff, administrators, and instructional staff should be provided in order to address changes as mentioned above and to address turnover in personnel. Additional information on energy effective operation and ongoing energy management is available in the ASHRAE Handbook.


656 657 Table 2.4. Energy Goals in the Context of the Acceptance Phase

Activities Responsibilities Where to Find Information

4.1-Prepare a punch list Owner, Designer, Construction Manager, Commissioning Authority

4.2-Conduct system performance tests Designer, Construction Manager, Commissioning Authority, General Contractor, Subcontractor

4.3-Submit completed operations and maintenance manuals

Commissioning Authority, General Contractor, Subcontractor

4.4-Provide operations and maintenance training for school staff

Commissioning Authority, General Contractor, Subcontractor

4.5-Establish building operations and maintenance program

Commissioning Authority, General Contractor, Subcontractor, Facility Staff

4.6-Resolve any remaining commissioning issues identified during the construction or occupancy phase

Owner, Construction Manager, Commissioning Authority, General Contractor, Subcontractor

4.7-Certify building as substantially complete


4.8-Purchase computers and other energy using appliances that meet Energy Star efficiency to reduce plug loads

Owner, Facility Staff

4.9-Monitor post-occupancy performance for one year

Commissioning Authority, Facility Staff

4.10-Create post-occupancy punch list Commissioning Authority, Facility Staff 4.11-Grant final acceptance Owner, Designer, Construction Manager,

Commissioning Authority

658


Chapter 3 Recommendations by Climate 659 660 661 662 663 664 665

666 667 668 669 670 671 672

This chapter contains a unique set of energy-efficient recommendations for each climate zone. The recommendation tables represent a way, but not the only way, for reaching the 30% energy savings target over Standard 90.1–1999. Other approaches may also save energy, but they are not part of the scope of this Guide; assurance of those savings is left to the user. The user should note that the recommendation tables do not include all of the components listed in Standard 90.1 since the Guide focuses only on the primary energy systems within a building.

Users should determine the recommendations for their construction project by first locating the correct climate zone. The U.S. Department of Energy (DOE) has identified eight climate zones for the United States, with each defined by county borders, as shown in Figure 3-1. These climate zones are based on temperature. In addition, some of the climate zones are divided into sub-zones based on humidity levels. Humid sub-zones are A zones, dry sub-zones are B zones, and Marine sub-zones are C zones. This Guide uses these DOE climate zones in defining the energy recommendations.

673 674

675 676 677 678 679 680 681 682 683 684

Figure 3-1. Climate Zone Map

Each of the climate zone recommendation tables includes a set of common items arranged by building subsystem: envelope, daylighting, lighting, HVAC systems, and service water heating (SWH). Recommendations are included for each item, or subsystem, by component within that subsystem. For some subsystems, recommendations depend on the construction type, HVAC system type, and daylighting potential. For example, insulation values are given for mass, steel-framed and wood-framed wall types. For other subsystems, recommendations are given for each subsystem attribute. For example, view glass recommendations are given for size, thermal transmittance, solar heat gain coefficient (SHGC), window orientation, and exterior sun control. For HVAC system type, recommended system efficiencies by system size are included in the how-to-tips in Chapter 5. For lighting, recommendations are provided for both a daylit option


and a non-daylit option. Where “No recommendation” is indicated in the “Recommendation” column of the tables, the user must meet at least the minimum requirements of Standard 90.1 or the requirements of local codes whenever they exceed the requirements of Standard 90.1.

685 686 687

688 689 690 691 692 693 694 695 696

697 698 699

700 701 702 703

The fourth column in each table lists references to how-to-tips for implementing the recommended criteria. The tips are found in Chapter 5 under separate sections coded for envelope (EN), daylighting (DL), electric lighting (EL), HVAC systems and equipment (HV), and water heating systems and equipment (WH) suggestions. Besides how-to-tips for design and maintenance suggestions that represent good practice, these tips include cautions for what to avoid. Note that each tip is tied to the applicable climate zones in Chapter 5. For the different types of HVAC systems, further details on recommended efficiencies based on system size are included with the referenced how-to-tips. The final column is provided as a simple checklist to identify the recommendations that are being used for a specific building design and construction.

Chapter 5 provides additional recommendations and strategies for savings for plug loads and exterior lighting over and above the 30% savings recommendations contained in the eight climate regions.

The recommendations presented are either minimum or maximum values. Minimum values include R-values, mean lumens/watt, SEER, SRI, EER, IPLV, AFUE, Ec, HSPF, COP, Et, EF, and insulation thicknesses. Maximum values include U-factors, SHGC, area, LPD, and friction rate.


704

705


Climate Zone 1 Recommendation Table for K-12 Schools 706 Item Component Recommendation How-to Tip x

Insulation Entirely Above Deck R-25 ci EN-1,2

Attic and Other R-30 EN-3,15,16,18

Metal Building R-19 EN-3,15,18 Roofs

SRI 0.78 EN-1

Mass (HC > 7 Btu/ft2) R-5.7 c.i. EN-5,15,18

Steel Framed R-13 EN-6,15,18

Wood Framed and Other R-13 EN-7,15,18

Metal Building R-16

Walls

Below Grade Walls No Recommendation EN-8,15,18

Mass R-4.2 c.i. EN-9,15,18

Steel Framed R-19 EN-10,15,18 Floors


Unheated No Recommendation EN-11,17,18 Slabs

Heated R-7.5 for 12 in. EN-12,17,18

Swinging U-0.700 E-N-13,18 Doors

Non-Swinging U-1.450 EN-14,18

Total Fenestration to Gross Wall Area Ratio 35% max EN-20

Thermal transmittance U-0.56 EN-19,24,28

Solar heat gain coefficient (SHGC) SHGC-0.25 all types and orientations EN-19,24,28

Window Orientation (AN * SHGCN + AS * SHGCS) >

(AE * SHGCE + AW * SHGCW) EN-21,23,26

Vertical Fenestration

Exterior Sun Control (S, E, W only) Projection factor > 0.5 EN-21,23,26

Interior Finishes Interior room surface average reflectance 80%+ on ceilings, 50%+ on walls DL-14

Toplit -

South Facing Roof Monitors: 8% - 11%

North Facing Roof Monitors: 12% - 15%

DL-1 – DL-19, DL-28 – DL-35

Sidelit -

South Facing: 8% - 11%

North Facing: 15% - 20%

DL-1 – DL-19, DL-20 – DL-27

Classroom Daylighting (Daylighting Fenestration to Floor Area Ratio)

Combined Toplit and Sidelit -

South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35

Gym Toplighting (Daylighting Fenestration to Floor Area Ratio) South Facing Roof Monitors: 5% - 8% DL-1 – DL-19,

DL-36,37

Lighting Power Density (LPD) 1.3 W/ft2 maximum EL-1 – EL-8

Light Source system efficacy (linear fluorescent and HID) 75 mean lumens/ watt minimum EL-1, 2

Light Source system efficacy (all other sources) 50 mean lumens/watt minimum EL-3, 4

Interior Lighting-

Daylit Option

Dimming Controls Daylight Harvesting Dim all fixtures in classrooms and gym, and other fixtures within 15 ft of sidelighting edge,

DL-16


Item Component Recommendation How-to Tip x

and within 10 ft of toplighting edge

Lighting Controls Manual on, Auto-off all zones EL-5,7, DL-16

Lighting Power Density (LPD) 0.9 W/ft2 EL-1 – EL-8

Light Source system efficacy (linear fluorescent) 85 mean lumens/watt minimum EL-1, 2


Lighting Controls - general Manual on, Auto-off all zones EL-5,7, DL-16

Interior Lighting-

Non-Daylit Option

Dimming Controls Daylight Harvesting Dim fixtures within 15 ft of sidelighting edge, and within 10 ft of toplighting edge DL-16

Air Conditioner ≥ 65 and < 135 kBtu/h 11.3 EER/11.5 IPLV


Air Conditioner ≥ 240 kBtu/h 10.6 EER/11.2 IPLV

Heat Pump < 65 kBtu/h 13.0 SEER/7.7 HPSF

Heat Pump ≥ 65 and < 135 kBtu/h 10.6 EER/11.0 IPLV/3.2 COP

Heat Pump ≥ 135 kBtu/h 10.1EER/11.5 IPLV/3.1 COP

Gas Furnace < 225 kBtu/h 80% AFUE or Et

Gas Furnace ≥ 225 kBtu/h 80% Ec

HV1, HV6-7, HV9

Economizer No recommendation HV12

Energy Recovery No recommendation HV8

Fans 1bhp/1000 cfm HV18

Packaged DX Rooftops (or DX Split Systems

Dedicated Outdoor Air System No recommendation HV11

Efficiency – Water Source (EER for cooling and COP for heating)

Cooling Mode 12 @ 86F and Heating Mode 4.5 @ 68F HV2, HV6-7, HV9

Efficiency – Groundwater Source (EER for cooling and COP for heating)

Cooling Mode 14.1 @ 77F and 17 @ 59F and Heating Mode 3.5 @ 32F and 4.0 @ 50F

HV2, HV6-7, HV9, AS??

Gas Boiler 85% Ec HV2, HV6, HV9

Economizer No recommendations HV12

Energy Recovery on dedicated outdoor air systems

50% Total Effectiveness

HV8

WSHP Duct Pressure Drop Total ESP < 0.2" HV18

WSHP System

Dedicated Outdoor Air System Required HV11

Air Cooled Chiller Efficiency 2.93 COP HV3, HV6-7, HV9, HV24

Gas Boiler 80% Et HV3, HV6, HV9, HV25




HV8

Pressure Drop Total ESP < 0.2" HV18

Fancoil and Chiller System


Rooftop Air Conditioner ≥ 240 kBtu/h 10.6 EER/11.2 IPLV


HV4, HV6-7, HV9


Energy Recovery 50% Total Effectiveness HV8

Packaged Rooftop VAV System

Fans 1.3 bhp/1000 cfm HV18









VAV and Chiller System


Outdoor air damped Motorized HV10, HV12 All Ventilation Systems Demand Control Required HV13

Friction rate 0.08 in w.c./100ft HV15

Sealing Seal Class B HV17

Location interior only HV15

Ducts

Insulation level R-6 HV16

Gas storage (>75 kBtu/h) 90% Et WH1-5

Gas instantaneous 0.81% Ef or 81% Et WH1-5

Electric Ef >0.99-0.0012 x Volume WH1-5 Service Water Heating

Pipe insulation (d < 1.5 in. / d ≥ 1.5 in.) 1 in./ 1.5 in. WH6

707 708 709

Note: If the table contains “No recommendation” for a component, the user must meet the more stringent of either Standard 90.1 or the local code requirements.


710 711





Metal Building R-13.0 + R-13.0 EN-3,15,18 Roofs

SRI 0.78 EN-1


Steel Framed R-13 EN-6,15,18


Metal Building R-16

Walls


Mass R-6.3 c.i. EN-9,15,18




Heated R-7.5 for 12 in. EN-12,17,18











Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35

Gym Toplighting (Daylighting Fenestration to Floor Area Ratio)



B Zones Only: Skylights: 4% - 5%

DL-1 – DL-19, DL-36,37



Interior Lighting-

Daylit Option

Light Source system efficacy (all other sources except certain dimmable and display loads – see text)

50 mean lumens/watt minimum EL-3, 4



Dimming Controls Daylight Harvesting Dim all fixtures in classrooms and gym, and other fixtures within 15 ft of sidelighting edge, and within 10 ft of toplighting edge

DL-16

Lighting Controls - control Manual on, Auto-off all zones EL-5,7, DL-16





Interior Lighting-

Non-Daylit Option


Air Conditioner ≥ 65 and < 135 kBtu/h 11.3 EER/11.5 IPLV HV1, HV6-7, HV9

















HV2, HV6-7, HV9, AS??




A Zones: 50% Total Effectiveness

B Zones: 50% Sensible Effectiveness HV8


WSHP System











Rooftop Air Conditioner ≥ 240 kBtu/h 10.6 EER/11.2 IPLV HV4, HV6-7, HV9






Energy Recovery A Zones: 50% Total Effectiveness
















Ducts






713 714 715



716


Climate Zone 3 Recommendation Table for K-12 Schools717 Item Component Recommendation How-to Tip x




SRI 0.78 EN-1


Steel Framed R-13.0 + R-3.8 ci EN-6,15,18


Metal Building R-16

Walls


Mass R-8.3 c.i. EN-9,15,18




Heated R-10 for 24 in. EN-12,17,18











Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35




B and C Zones Only: Skylights: 4% - 5%

DL-1 – DL-19, DL-36,37



Interior Lighting-

Daylit Option





DL-16






Interior Lighting-

Non-Daylit Option










Economizer > 54 kBtu/h HV12









HV2, HV6-7, HV9, AS??





B Zones: 50% Sensible Effectiveness C Zones: no recommendation

HV8


WSHP System








HV8




Rooftop Air Conditioner ≥ 240 kBtu/h 10.6 EER/11.2 IPLV HV4, HV6-7, HV9 Packaged Rooftop VAV System







HV8








HV8








Ducts






718 719 720



721






SRI No recommendation EN-1


Steel Framed R-13 + R-7.5 ci EN-6,15,18


Metal Building R-19

Walls


Mass R-8.3 c.i. EN-9,15,18















Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35




B and C Zones Only: Skylights: 4% - 5%

DL-1 – DL-19, DL-36,37



Interior Lighting-

Daylit Option





DL-16






Interior Lighting-

Non-Daylit Option



















HV2, HV6-7, HV9, AS??






HV8


WSHP System








HV8




Rooftop Air Conditioner ≥ 240 kBtu/h 10.6 EER/11.2 IPLV HV4, HV6-7, HV9 Packaged Rooftop VAV System







HV8








HV8








Ducts






723 724 725



726









Wood Framed and Other R-13.0 + R-3.8 ci EN-7,15,18

Metal Building R-13.0 + R-13.0

Walls

Below Grade Walls R-7.5 ci EN-8,15,18

Mass R-10.4 ci EN-9,15,18















Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35





DL-1 – DL-19, DL-36,37



Interior Lighting-

Daylit Option





DL-16






Interior Lighting-

Non-Daylit Option



















HV2, HV6-7, HV9, AS??







WSHP System


Air Cooled Chiller Efficiency 9.6 EER 11.5 IPLV HV3, HV6-7, HV9, HV24









Rooftop Air Conditioner ≥ 240 kBtu/h 10.0 EER/10.4 IPLV HV4, HV6-7, HV9






















Ducts






728 729 730



731











Walls


Mass R-13.3 ci EN-9,15,18



Unheated R-10 for 24 in. EN-11,17,18 Slabs












Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35





DL-1 – DL-19, DL-36,37



Interior Lighting-

Daylit Option





DL-16






Interior Lighting-

Non-Daylit Option


Air Conditioner ≥ 65 and < 135 kBtu/h No recommendation


Air Conditioner ≥ 240 kBtu/h No recommendation


Heat Pump ≥ 65 and < 135 kBtu/h No recommendation

Heat Pump ≥ 135 kBtu/h No recommendation



HV1, HV6-7, HV9










HV2, HV6-7, HV9, AS??







WSHP System











Rooftop Air Conditioner ≥ 240 kBtu/h No recommendation


HV4, HV6-7, HV9



Energy Recovery A Zones: 50% Total Effectiveness HV8



B Zones: 50% Sensible Effectiveness















Ducts






733 734 735



736











Walls


Mass R-12.5 ci EN-9,15,18




Heated R-15 for full slab. EN-12,17,18











Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35



North Facing Roof Monitors: 7% - 10% DL-1 – DL-19, DL-36,37




Interior Lighting-

Daylit Option


DL-16









Interior Lighting-

Non-Daylit Option










HV1, HV6-7, HV9










HV2, HV6-7, HV9, AS??





HV8


WSHP System







HV8






HV4, HV6-7, HV9



















Ducts






738 739 740



741











Walls

Below Grade Walls R-15 ci EN-8,15,18

Mass R-16.7 ci EN-9,15,18




Heated R-15 for full slab. EN-12,17,18











Toplit -



DL-1 – DL-19, DL-28 – DL-35

Sidelit -



DL-1 – DL-19, DL-20 – DL-27



South Facing: 8%

North Facing: 15%

DL-1 – DL-19, DL-20 – DL-35

Gym Toplighting (Daylighting Fenestration to Floor Area Ratio


North Facing Roof Monitors: 7% - 10% DL-1 – DL-19, DL-36,37




Interior Lighting-

Daylit Option


DL-16









Interior Lighting-

Non-Daylit Option










HV1, HV6-7, HV9










HV2, HV6-7, HV9, AS??




50% Sensible Effectiveness HV8


WSHP System






50% Sensible Effectiveness HV8






HV4, HV6-7, HV9


Energy Recovery 50% Sensible Effectiveness HV8









Energy Recovery 50% Sensible Effectiveness HV8








Ducts






743 744 745



Chapter 4 Case Studies 746 747 748 749 750 751

The case studies in this chapter illustrate techniques and methods that are discussed in this guide. All of these building pre-date the publication of the guide and were not developed using the Recommendation tables in Chapter 3. Energy numbers are provided to benchmark these buildings against future buildings; however, theses schools may or may not have achieved the 30% level as if they had been constructed entirely according to the recommendations in this guide. The reader is encouraged to view additional case studies at www.ashrae.org/aedg. Furthermore, readers are encouraged to submit cast studies at

752 www.ashrae.org/aedg that have

used the guide to achieve the 30% savings. Case studies provide the motivation and the examples for others to follow.

753 754 755

756 757 758 759 760 761 762

763 764 765 766 767 768 769 770 771 772 773 774 775

Third Creek Elementary School, Statesville, NC Third Creek Elementary School in Statesville, North Carolina is located in a suburban setting in Climate Zone 4. The 92,000 ft2 building was completed in July 2002. The spaces in the school include classrooms, offices, public assembly spaces, cafeteria, gymnasium, athletic field, and restrooms. This new construction project consolidated and replaced two existing aging schools at a total project cost of $8.7M (land purchase excluded). The finished school was the first K-12 school to earn a LEED v2.0 Gold Certification from the USGBC.

The building team made an explicit commitment to high performance design from the beginning of the project. Many educational and community force features are incorporated such as locating the gymnasium, stage, and dining room so that they may operate on separate systems after hours for community use, while the academic portion of the school is secured and not using energy. Energy Demand was lowered though energy efficient equipment and design, including extensive day-lighting. Third Creek has an east-west axis orientation on the site. The southern façade has overhangs on the windows to shade from the summer sun. Each of the classrooms in the school makes use of light shelves to promote the dispersion of the daylight. In addition to the light shelves, reflective ceiling tiles were used to increase the effectiveness of the daylighting. The computer models of the building show a reduction in annual energy costs by 25% over the ANSI/ASHRAE/IESNA Std 90.1-1999. The building’s energy efficiency has improved each year to an annual energy reduction of 33.5% measured in 2005.


776 Front Entrance View Looking North 777

778 Floor Plan Entrance Hallway 779

780

781


782 Classroom w783

784 ith Internal Light Shelf


Table of Energy Savings Measures: 785

Energy Savings Measures Description Tips Envelope Building Orientation East-West Axis Opaque Components R-45 Roof, R-22 Walls Vertical Glazing All Windows Low-E; View Glass U-34

46% Transmittance Light Shelves Glass; U-30 70% Transmittance

Lighting Classroom T-8 Controls Four levels of control per classroom Occupancy Sensors Day Lighting Window design Overhangs on southern façade Interior light shelves in all classrooms HVAC Equipment High efficiency water source heat

pu

mps w/ variable frequency drives – EER – 14.5%; COP of 4.5

Boilers 97% Thermal Efficiency – Condensing Cooling Tower 5 levels of control to match loads with

minimal energy output

Energy Recovery Ventilators Control Humidity; not to exceed 55% Service Water Heating No Advanced Savings System Controls Measurement and Verification Direct Digital Control System Temperature Control Individual Classroom Control Additional Savings Plug Loads No Advanced Savings Computers Energy Star features enabled Kitchen Equipment No Advanced Savings Swimming Pools/Ice Rinks No Advanced Savings Specialty Spaces (labs) No Advanced Savings Exterior/Field/Parking lot Lighting No Advanced Savings Renewable Energy None Energy Use Characteristics Simulated Site Energy Use Intensity 59.6 kBtu/sq ft/year Measured Site Energy Use Intensity 59.8 kBtu/sq ft/year (purchased) Years of Measured Data 3 years

786


Zach Elementary School, Fort Collins, CO 787 Zach Elementary School is located in Fort Collins, Colorado, and is part of the Poudre School 788 District. Zach Elementary is the first of the school district’s new generation of sustainable 789 schools. The district is located in a suburban setting along the front range of the Rocky 790 Mountains in Climate Zone 5. Zach, a 67,412 square foot facility and capacity of 525 students, 791 opened at the beginning of the 2002-2003 school year. This school was built using guidelines 792

793 oo .org/d ds/Op nstruct

developed by the school district. http://www.ps sch lo( d ls ocumentlibrary/down a erations/Plan_Design_and_Co794 n/Sus ainable_Desig _Guidio t n elines.pdf.) 795

mitment to high performance design from the beginning 796 ent and design, 797

ng, controls, . The 2001 cost this building was $6.27 798 100 per square foot. This ated de ign and high 799 lements. The additio was 3% of the design 800 is e cost was less th same size built in this area. 801

as 42 kBtu per squar of $0.43/ft2. Zach was one of 802 tioned schools in the district and uses 37% less energy than the other 29 schools 803

onditioned. 804

Zach is also the first school to be apart of ns Wind Power Program. The energy that 805 ases for the school is 100806 district is able to avoid th d pr ent the 807

emissions of 1,200 pounds of carbon diox808

signed around dayli n wheth the 809 m faces north or south, the electri e of roof-810

mounted photo-sensors. Tinted view and clerestory windows are used in the classrooms. The 811 clerestory windows make use T rid ceilings 812

have also been sloped to improve the dayl ffect. The ceilings slope away from the 813 to increase the ceiling brightness ylighting devices are used bring 814

into the spaces. 815

The building team made an explicit comnd was lowered of the project. Energy dema

including extensive daylightithough energy efficient equipm

and ice storagemillion or less than $performance design e

can be contributed to integrnal cost for the integrated design

s

budget. At the time th05 w

an typical schools of theith utility costs Energy use in 20

ir-condie foot, w

the first ain the district that are not air-c

Fort Collithe district purchwind energy, the

percent wind energy. With the use of the renewable e burning of 671 pounds of coal an

ide per student each year. ev

The classrooms are de ghting principles. Depending o erclassroo c lighting is controlled by one of two s ts

south facing of overhangs to provide shade. The ighting e

-g

windows . Tubular da todaylighting deep

816 est Typical Classroom with Daylighting 817

818 North View of School looking W


819 820 821 822 823

Ice Storage System Roof View – Tubular Inside View – Tubular Daylighting Device Daylighting Device with Diffuser Table of Energy Savings Measures:

Energy Savings Measures Description Tips Envelope Building Orientation East West – Most Classrooms face

north

Opaque Components Roof – R30 ; Walls R-17 Vertical Glazing Low-e Lighting Controls – Occupancy Sensors Yes in conjunction with Daylighting

Controls

Daylighting Window design Light Shelves/shades on south facing

windows – North facing have no shading

Daylighting Sensors Used to control Classroom light HVAC VAV for all spaces except DX units for

two computer labs

Equipment Roof Top Ventilation Units with 4 pipe system

Boilers Natural Gas Cooling Tower No advanced savings Ice Storage Supplies cooling through the VAV

system

System Controls Measurement and Verification Full Commissioning Temperature Control Individual Room Thermostats CO2 Sensors Yes employed to control HVAC Additional Savings Plug Loads No advanced savings Computers No advanced savings Kitchen Equipment No advanced savings Specialty Spaces (labs) No advanced savings Exterior/Field/Parking lot Lighting High Pressure Sodium Renewable Energy Electrical supply – 100% Wind Energy Use Characteristics Simulated Site Energy Use Intensity 40 kBtu/ft2 Measured Site Energy Use Intensity 42 kBtu/ft2 – 37% less than average

non –AC schools

Years of Measured Data 3 years Photo’s and Data are provided by Poudre School District and personal files. 824


Alder Creek Middle School, Truckee, CA 825 Alder Creek Middle School in Truckee, California near Lake Tahoe is located in a rural setting 826 in Climate Zone 6. The 87,000 square foot building was opened in 2004. The spaces in the 827 school include classrooms, offices, public assembly spaces, cafeteria, gymnasium, athletic fields, 828 and restrooms. This new construction project was designed in the core to serve 1000 students 829 with an initial capacity of 700 in sixth through eighth grades. The project was a CHPS 830 demonstration School. 831

The school, using CHPS criteria, is a showcase of high performance building strategies including 832 natural daylighting, energy efficiency, healthy indoor air quality, proper acoustics, building 833 commissioning, sustainable materials, waste reduction, preventive maintenance, site protection 834 and water conservation. Ground source heat pumps with an energy savings of over 51% 835 compared to air-based HVAC systems. The school uses 288 wells that are drilled 300 feet deep 836 beneath the soccer field. Energy use is split evenly annually between electricity and natural gas. 837 The construction cost was $24 million or $275/square foot with a total of $30 million including 838 contingency and soft costs. 839

840

841 842

843

Aerial of School Site for Building Orientation – From Googlemaps.com

Main Entrance


Typical Classroom

844 room showing daylighting and light percent upl ht and 40 percent 845

t. Top row of windows is designed to provide the daylighting to the space. 846 847

Typical Class ing systems. Light fixtures are 60 igdownligh

showing daylighting and lighting systems


848

849 Table of Energy Savings Measures

Energy Savings Measures Description Tips Envelope Building Orientation East – West Opaque Components Wall and Roof R-19; Cool Roof Vertical Glazing Low –E Lighting Lighting Systems Used T-5 Direct/Indirect in classrooms and

offices; T-5 HO in Gym; T-8 in all

other areas Controls Sensor on row of lights near windows;

Room Occupancy Sensors

Daylighting Window design Low-e with Dual Glazing Controls Blinds are inside windows and act as

light shelves

Skylights Stairwells in Classroom Wing HVAC Equipment Ground Source Heat Pumps Boilers Backup Cooling Tower None Service Water Heating Dedicated Domestic Boiler for Hot

Water

System Controls Measurement and Verification EMCS System used District Wide Temperature Control Individual Room Controls – 5 degree

limit on user control

CO2 Sensors Used in Gym and Cafeteria Additional Savings Plug Loads None Computers Energy Star features enabled Kitchen Equipment None Swimming Pools/Ice Rinks None Specialty Spaces (labs) None Exterior/Field/Parking lot Lighting Metal Halide Renewable Energy None Energy Use Characteristics Simulated Site Energy Use Intensity 25% Below Title 24 in California Measured Site Energy Use Intensity 54 kBtu/ft2 Years of Measured Data 2.75

850


Westwood Elementary School, Minnesota: 851 erman, Minnesota, is located in a mixed suburban/rural 852

e 75,000 squ ory building has a curren ity of 853 ts with the core facilities capac of 750 students. Currently it supports grades 3 854

l opened in the fall o built at a cost of $12 m lion. The 855 r budget validating rformance schools do not 856

than a typical school. The scho acent to Sherburne Wildlife 857 es in the school include es, cafeteria, 858

, and athletic field. The schoo esign guidance and resulted in it 859 irst K-12 school to earn a LEED fourth in the 860

861

862 igure. Aerial View of School 863

The building team made an explicit commitment to high performance design from the 864 g of the project. Westwood elem incorporated daylighting, increased insulation, 865

ient lighting with occupancy gain and loss, 866 occupancy and day-light sensors control electric lighting, heat recovery wheels and humidity 867

displacement ventilation, 94% heaters, energy efficient gas 868 quipment and a condensing boi ble wind ws add to the 869

ings features of the school allow uildi g was oriented 870 ize solar and wind pa ed to m et the multiple 871

needs. Many edu872 um, stage, and din erate on separate systems 873

n projected kBtu per squar foot annually. 874 has been m eled, as the bu ding has been 875

the energ mmer v ancy. During 876 the actua this building has ranged 877

.0 kBtu per square foot .4 kBtu per squa foot. 878

itioning the ventilation air is total energy cost in any school. 879 y consumption and pe heels. he heat wheels 880

ercent of the energy from the exhaust air stream and transfer it to the 881 idif onths. The use of the heat wheel 882

n costs The heat wheels re used in the 883 cooling in the summ nths. They transfer sensible and latent energy 884

. 885

886 iciency Boilers 887

888

Westwood Elementary School in Zimmsetting in climate zone 6. Th are foot two-st t capac500 studen itythrough 5. The schoo f 2004 and was ilbuilding came in unde the statement that High Pecost more ol site is 26 acres and in adjRefuge. The spac classrooms, offices, public assembly sp

l used LEED as the dac

gymnasium being the fnation.

v2.1 certification in Minnesota and the

Picture TBD F

beginnin entary energy effic sensors, low-e glass to both control heat

control, efficient gas hot water kitchen e ler for heating needs. Opera oenergy sav ing for passive ventilation. The b non the site to maximcommunity and sc

tterns. The building was design ehool

as locating the gymnasicational and community features are incorporated such ing room so that they may op

after hours The energy desigoperation

an energy use of 53.7 at mod

e The actual building odified from th ilcooled year round compared to

of operationy model that was based on suannual energy used to operate

acthe first three years

to 84l

between 75.9 , with an average of 78 re

Cond a major portion of the s In order to cut energ ak loads, Westwood uses heat w Tcan recover as much as 80 psupply air stream for heating and humin the winter can cut humidificatio

ication in the winter m by up to 60 percent. a

opposite manner for er mofrom the ventilation air to the exhaust air stream

Picture TBD Figure. Condensing 97% eff


889 890 Table of Energy Savings Measures:

Energy Savings Measures Description Tips Envelope Building Orientation East-West Axis Opaque Components R-18 walls and R-22 roofs Roofing 5-ply 30 year warranty BUR Vertical Glazing U-value of 0.29, SC of 0.49 and visual

transmittance of 0.69

Lighting Controls Occupancy Sensors and Daylighting

sensors Type of Lighting used in various Areas 15% Direct/85% Indirect T5 Pendent

Fixtures

HVAC Equipment Fan Powered VAV w/ Displacement

Ventilation

Boilers HW Condensing Cooling Air-Cooled Chiller (10.7 EER) Pumping VFDs on HW & CHW Distribution Window design Operable for Natural Ventilation Energy Recovery Desiccant Whell Service Water Heating 94% efficient condensing (gas) System Controls Measurement and Verification Systems Commissioning Temperature Control Web-based BAS Demand-Controlled Ventilation Gymnasium & Cafeteria AHUs Additional Savings Plug Loads No Advanced Savings Computers No Advanced Savings Kitchen Equipment Energy Efficient Equipment (Gas) Swimming Pools/Ice Rinks None Specialty Spaces (labs) No Advanced Savings Exterior/Field/Parking lot Lighting No Advanced Savings Renewable Energy None Energy Use Characteristics Simulated Code Base 113.7 kBtu/ft2 Simulated Design Model 53.7 kBtu/ft2 (Based on No Summer

Operations or cooling year round)

Measured Site Energy Use Intensity 78.4 kBtu/ft2 (with increased operating hrs)

Years of Measured Data 3.0 891 Photo’s and Data are provided by Elk River Area School District ISD 728 and Johnson Controls 892


The Dalles Middle School, Oregon 893 The Dalles Middle School in The Dalles, Oregon is located in a rural area along the Columbia 894 River on the eastern slopes of the Cascades and is in Climate Zone 5. This 96,500 square foot 895 school opened in September of 2002 at a cost of $12.5 Million or about $104 per square foot not 896 including site work. The spaces in the school include classrooms, offices, public assembly 897 spaces, cafeteria, gymnasium, and athletic fields. The school was built for 600 students and on a 898 13 acre site. This new facility replaced a facility that was classified as substandard and had been 899 mandated for closure. LEED design criteria was used in the development of the project. A sub-900 surface geological problem requiring constant removal of water was corrected and used in 901 providing both heating and cooling for this facility thus reducing the energy use and costs. 902

The architectural firm and the school district were committed to designing and constructing a 903 High Performance school that would provide the best environment to the students and staff and 904 reduce energy consumption. The building included many HP Design elements which impacted 905 energy use: T-5 indirect lighting throughout, daylighting in all classrooms, natural cooling and 906 ventilation capability, geothermal heating and cooling. Internal light shelves, and 907

classrooms have either a northern 908 nimize unwanted solar gains. 909

t deeper into the classrooms. Light 910 olor ceilings and walls are used to help reflect the light into the rooms. The classrooms have 911

tubular daylighting devices located near the interior walls to help provide daylight to the interior 912 of the rooms. 913

The geothermal system was based on a geological problem, a landslide area adjacent to the 914 school site, which was being dewatered through wells. The rate of flow was about 130 gallons a 915 minute. Storage tanks were installed and pipes installed and the water which was being pumped 916 directly to the Columbia River was now piped through ground source heat pumps to provide 917 either cooling or heating and then pumped to the river. The water is also used to irrigate the 918 fields. The school also uses natural ventilation when the weather conditions allow. The 919 windows in the classrooms can be opened to pull fresh air in, while passive ventilation stacks 920 pull the air out on the opposite side of the class rooms. Natural ventilation and cooling is being 921 controlled by weather conditions. Indicator lights in each room notify the staff when windows 922 should be opened. Using the chimney effect, a ventilation stack in each area draws in outside air 923 using with a wind turbine at the top of the stack. When conditions change mechanical 924 ventilation comes on the indicators in the rooms tell occupants when close the windows. 925

commissioning. The school has an east-west orientation so theor southern exposure to maximize daylighting potential and mi

Lightshelves are used on the windows to project the daylighc


926

927 t Side of School w th Window Screens 928

cing Front of the School 929 930

Eas i

And North Fa


Table of Energy Savings Measures:

931 932

Energy Savings Measures Description Tips Envelope Building Orientation East West Opaque Components Thermal Mass Design to Reduce Heat

gain by 82% Vertical Glazing Low E Lighting Controls Occupancy sensors and daylighting

controls

Daylighting Window design High vertical fenestration. Low-e with

Exterior and Interior Light Shelves/shades and exterior shades

HVAC Equipment Water Source Heat Pumps Boilers None Cooling Tower None Natural Ventilation Wind driven exhaust stacks Service Water Heating High Efficiency hot water heaters System Controls Measurement and Verification Commissioning Temperature Control Individual Room Controls Additional Savings Plug Loads No advanced energy savings Computers No advanced energy savings Kitchen Equipment No advanced energy savings Swimming Pools/Ice Rinks None Specialty Spaces (labs) Exterior/Field/Parking lot Lighting HID Renewable Energy None Energy Use Characteristics Simulated (kBtu/sq ft/year) Awaiting info Measured (Btu/sq ft/year) Years of Measured Data 933 934

Photos and Data have been provided by BOORA Architects, Oregon Energy Office and Larry Schoff. 935 936


Bolingbrook High School, Bolingbrook, IL 937 Bolingbrook High School in Bolingbrook, Illinois is located in a suburban setting in Climate 938 Zone 5. This 569,000 square foot building has a rated capacity of 3600 students. The 939 educational planning concept of school-within-a-school was used with two academic houses in 940 distinct wings with interior courtyards to maximize exterior views and daylight. 941

942 of School Loo Natural Field

943 xisting high schools and crowded and the other larger with 944 large number of stud A master plan 945

for the district was developed which inclu ns to the larger of 946 the two existing high schools and the renovation of the smaller high school to a middle school. 947

ool provided the needed long-term residential growth projected to 948 ilding was to be complet va using an 949

integrated services delivery model patterned after design-build delivery. The total project cost 950 illion or about $169/square foot with the construction cost of $156/square foot or 951 339 per student. This project w952

The building team made an explicit comm sign from the beginning 953 of the project and registered the project w ol-within-a-school 954 concept the school incorporated a Theatric gym and a field 955 house which is partially buried to reduce s tal features included the 956 use or inclusion of: 1) bio-swales to filter f; 2) a well 957

for athletic fields and ind automated digital control 958 for automatic control of HVAC ed le set 959

according to the projected use of the diffe y savings, fans do 960 heduled and room thermo ly programmed between 68 and 74 961 densate recovery system that 360,000 gallons of water 962

lects and reuses water from th rooftop chillers; 6) lights, equipped with override 963 ill automatically be turned on fore school starts and 964

will turn them off after school; and, 7) lig the main concourse are 965 aylight harvesting sensors966

View king East across a The district had two e one smaller space and requiring a ents to cross a major interstate daily.

ded this new high school, renovatio

The new high sch space for thecontinue. The bu ed within 29 months after bond appro l

was $96 mabout $22, as bid in 2002.

itment to high performance deith the USGBC. Besides the schoal Performance auditorium, a PE cale. Energy and environmenimpurities from surface water runofigenous plantings; 3) a firrigation system

system allowsully

systems turning on/off via a time schrent areas; 4) to optimize large energ

ital

u

not run unless sc 5) a con

stats are dig is projected to savedegrees;

annually col w

e switches, via a programmed schedule be

hts in the upper levels ofequipped with d .


967 Cafeteria Typical Classroom 968

Classroom Courtyard allowing access to Daylighting Main Corridor

Lighting / Daylighting in Media Center


Table of Energy Savings Measures:

Energy Savings Measures Description Tips Envelope Building Orientation North South Opaque Components CMU and Brick; wall insulation 2 inch

rigid in cavity with core insulation in CMU.

Vertical Glazing 1” Insulated Roofing System PVC membrane with white reflectance

Lighting Controls T-8 lamps with smart breakers.

Automatic turnoff based on schedule. Override capability in one hour increments. Metal halide with light sensors in hallways to auto turn off when natural light sufficient; in classrooms two switches to allow for 33, 67 and 100% lighting

Daylighting 90% of occupied spaces have daylighting; controls on main corridor with clerestory

Window design 1” insulated HVAC Equipment Boilers Constant primary pumping and

secondary VAV pumping

Cooling Tower No advanced savings Service Water Heating No advanced savings System Controls Measurement and Verification Full Commissioning included Temperature Control Individual classrooms Additional Savings Plug Loads No advanced savings Computers No advanced savings Kitchen Equipment No advanced savings Swimming Pools/Ice Rinks No advanced savings

Specialty Spaces (labs) No advanced savings

Exterior/Field/Parking lot Lighting Metal Halide “Cut-off” with 0 footcandles at lot line

Renewable Energy None Energy Use Characteristics Simulated Site Energy Use Intensity Awaiting data Measured Site Energy Use Intensity Years of Measured Data 3 Years


969 Aerial View of Campus and surrounding area 970

Data and photos provided by Wight & Company. 971

972

973 974 975

976


Chapter 5 How to Implement Recommendations 977 Recommendations are contained in the individual Tables in Chapter 3, Recommendations by 978 Climate. The following information is intended to provide guidance in good practice guidance 979 for implementing the recommendations as well as cautions to avoid known problems in energy 980 efficient construction. 981

Envelope 982 983

Good Design Practice 984 985 EN-1 Cool Roofs (Climate Zones: 1, 2, 3) 986

In order to be considered a cool roof a Solar Reflectance Index (SRI) of 78 or higher is 987 recommended. A high reflectance keeps much of the sun’s energy from being absorbed while a 988 high thermal emittance radiates away any solar energy that is absorbed, allowing the roof to cool 989 more rapidly. Cool roofs are typically white and have a smooth surface. Commercial roof 990 products that qualify as cool roofs fall into three categories: single-ply, liquid-applied and metal 991 panels. Examples are presented in Table 5-1. 992

993

Table 5-1 Examples of Cool Roofs 994

Category Product Reflectance Emissivity SRI

Single-ply White PVC (polyvinyl chloride) 0.86 0.86 107

Single-ply White CPE (chlorinated polyethylene)

Single-ply White CPSE (chlorosulfonated polyethylene, e.g. Hypalon)

0.85 0.87 106

Single-ply White TSO (thermoplastic polyolefin) 0.77 0.87 95

Liquid-applied White elastomeric, polyurethane, acrylic coating

0.71 0.86 86

Liquid-applied White paint (on metal or concrete) 0.71 0.85 86

Metal Panels Factory-coated white finish 0.90 0.87 113

995

The solar reflectance and thermal emmittance property values represent initial conditions 996 as determined by a laboratory accredited by the Cool Roof Rating Council. 997

998 A Solar Reflectance Index (SRI) can be determined by the following equations: 999

1000

SRI = 123.97 – 141.35(χ) + 9.655(χ2) 1001

1002

where 1003


1004

χ = 0.125205.9

603.0797.20+×

×−×ε

εα 1005

1006

and 1007

1008

α = Solar Absorptance = 1 – Solar Reflectance 1009

ε = Thermal Emissivity 1010

1011

which were derived from ASTM E1980 assuming a medium wind speed. 1012

1013

EN-2 Roofs, Insulation Entirely above Deck (Climate Zones: all) 1014 The insulation entirely above deck should be continuous insulation (c.i.) rigid boards 1015

because there are no framing members present that would introduce thermal bridges or short 1016 circuits to bypass the insulation. 1017

1018

Figure 5-1. (EN2) To be defined. 1019

1020

When two layers of continuous insulation are used in this construction, the board edges 1021 should be staggered to reduce the potential for convection losses or thermal bridging. If an 1022 inverted or protected membrane roof system is used, at least one layer of insulation is placed 1023 above the membrane while a maximum of one layer is placed beneath the membrane. 1024

1025

EN-3 Roofs, Attics and Other Roofs (Climate Zones: all) 1026 Attics and other roofs include roofs with insulation entirely below (inside of) the roof 1027

structure (i.e., attics and cathedral ceilings) and roofs with insulation both above and below the 1028 roof structure. Ventilated attic spaces need to (a) have the insulation installed at the ceiling line. 1029 Unventilated attic spaces may have the insulation installed at the roof line. When suspended 1030 ceilings with removable ceiling tiles are used, (b) the insulation needs to be installed at the roof 1031 line. For buildings with attic spaces, ventilation should be provided equal to 1 ft2 of open area 1032 per 100 ft2 of attic space. This will provide adequate ventilation as long as the openings are split 1033 between the bottom and top of the attic space. 1034

1035

Figure 5-2. (EN3) To be defined.. 1036

1037

EN-4 Roofs, Single Rafter (Climate Zones: all) 1038 Single rafter roofs have the roof above and ceiling below both attached to the same wood 1039

rafter, and the cavity insulation is located between the wood rafters. Continuous insulation, 1040 when recommended, is installed to the bottom of the rafters and above the ceiling material. 1041


Single rafters can be constructed using solid wood framing members or truss type framing 1042 members. The cavity insulation should be installed between the wood rafters and in intimate 1043 contact with the ceiling to avoid the potential thermal short-circuiting associated with open or 1044 exposed air spaces. 1045

1046


1048

EN-5 Walls, Mass (Climate Zones: all) 1049 Mass walls are defined as those with a heat capacity exceeding 7 Btu/ft2·°F. Insulation 1050

may be placed either on the inside or the outside of the masonry wall. When insulation is placed 1051 on the exterior of the wall, (a) rigid continuous insulation (c.i.) is recommended, see Figure 5-4. 1052 When insulation is placed (b) on the interior of the wall, a furring or framing system may be 1053 used, provided the total wall assembly has a U-factor that is less than or equal to the appropriate 1054 climate zone construction listed in Appendix A. 1055

1056

1057 Figure 5-4. (EN5) Walls, mass - any concrete or masonry wall with a heat capacity exceeding 7 1058 Btu/ft2·°F. 1059

The greatest advantages of mass can be obtained when insulation is placed on the exterior 1060 of the mass. In this case, the mass absorbs heat from the interior spaces that are later released in 1061 the evenings when the buildings are not occupied. The thermal mass of a building (typically 1062 contained in the building’s envelope) absorbs heat during the day and reduces the magnitude of 1063 indoor air temperature swings, reduces peak cooling loads and transfer a portion of the absorbed 1064 heat into the night hours. The cooling load can then be covered by passive (natural) cooling 1065 techniques when (if) the outdoor conditions are more favorable. An unoccupied building can 1066 also be pre-cooled during the night by natural or mechanical ventilation thus reducing the 1067

1068

1069 1070

ermal environment. This increases thermal comfort, particularly during mild seasons (spring 1071 and fall), during large air temperature changes (high solar gain), and in areas with large day-1072 night temperature swings. 1073

A designer should keep in mind that the occupant will be the final determinant factor on 1074 the extent of the utilizability of any building system, including thermal mass. Changing the use 1075 of internal spaces and surfaces can drastically reduce the effectiveness of thermal storage. The 1076 final use of the space must be considered when making the cooling load calculations and 1077 incorporating possible energy savings from thermal mass effects. 1078

1079

cooling energy use.

Thermal mass also has a positive effect on occupant thermal comfort. High mass rior air and wall temperature variations and sustain a stable overall buildings attenuate inte

th


EN-6 Walls, Steel Framed (Climate Zones: all) 1080 Cold-formed steel framing members are thermal bridges to the cavity insulation. Adding 1081

exterior foam sheathing as continuous insulation (c.i.) is the preferred method to upgrade the 1082 wall thermal performance because it will increase the overall wall thermal performance and 1083 tends to minimize the impact of the thermal bridging. 1084

Alternative combinations of cavity insulation and sheathing in thicker steel-framed walls 1085 can be used provided that the proposed total wall assembly has a U-factor that is less than or 1086 equal to the U-factor for the appropriate climate zone construction listed in Appendix A. Batt 1087 insulation when installed in cold-formed steel framed wall assemblies is to be ordered as “full 1088 width batts” and installation is normally by friction fit. 1089


1091

EN-7 Walls, Wood Frame and Other (Climate Zones: all) 1092 Cavity insulation is used within the wood-framed wall, while rigid continuous insulation 1093

(c.i.) is placed on the exterior side of the framing. Care must be done to have a vapor barrier on 1094 the warm side of the wall and to utilize a vapor barrier faced batt insulation product to avoid 1095 insulation sagging away from the vapor barrier. 1096

Alternative combinations of cavity insulations and sheathings in thicker walls can be used 1097 provided the total wall assembly has a U-factor that is less than or equal to the appropriate 1098 climate zone construction listed in Appendix A. 1099

1100


1102

EN-8 Below-Grade Walls (Climate Zones: all) 1103 Insulation, when recommended, may be placed either on the inside or the outside of the 1104

below-grade wall, see Figure 5-7. If placed on the exterior of the wall, (a) rigid continuous 1105 insulation (c.i.) is recommended. If placed on the interior, (b) a furring or (c) framing system is 1106 recommended provided the total wall assembly has a C-factor that is less than or equal to the 1107 appropriate climate zone construction listed in Appendix A. 1108

1109 Figure 5-7. (EN8) Below grade walls - outer surface of the wall is in contact with the earth, and 1110 the inside surface is adjacent to conditioned or semi-heated space. 1111

1112


EN-9 Floors, Mass (Climate Zones: all) 1113 Insulation should be continuous and either integral to or above the slab. It should be 1114

purchased by the conductive R-value. This can be achieved by (a) placing high-density extruded 1115 polystyrene as continuous insulation (c.i.) above the slab with either plywood or a thin layer of 1116 concrete on top. Placing insulation below the deck is not recommended, due to losses through 1117 any concrete support columns or through the slab perimeter. 1118

Exception: Buildings or zones within buildings that have durable floors for heavy 1119 equipment could (b) place insulation below the deck. 1120

When heated slabs are placed below grade, below-grade walls should meet the insulation 1121 recommendations for perimeter insulation according to the heated slab-on-grade construction. 1122

1123


1125

EN-10 Floors, Steel Joist or Wood Frame (Climate Zones: all) 1126 Insulation should be installed parallel to the framing members and in intimate contact 1127

with the flooring system supported by the framing member in order to avoid the potential 1128 thermal short circuiting associated with open or exposed air spaces. 1129

Nonrigid insulation should be supported from below no less frequently than 24 in. on 1130 center. 1131

1132


1134

EN-11 Slab-on-Grade Floors, Unheated (Climate Zones: 5, 6, 7, 8) 1135 Continuous rigid insulation should be used around the perimeter of the slab and should 1136

reach the depth listed in the recommendation or to the bottom of the footing, whichever is less. 1137 In climate zones 5 - 8 and in cases where the frost line is deeper than the footing, continuous 1138 insulation should be placed beneath the slab as well. 1139

1140


1142

EN-12 Slab-on-Grade Floors, Heated (Climate Zones: all) 1143 When slabs are heated, see Figure 5-11, continuous rigid insulation should be used 1144

around the perimeter of the slab and should reach to the depth listed in the recommendation or to 1145 the bottom of the footing, whichever is less. Additionally, in climate zones 5 - 8, continuous 1146 insulation should be placed below the slab as well. Note that it is important to use the 1147 conductive R-value for the insulation as radiative heat transfer is small in this application. 1148

1149

Note: In areas where termites are a concern and rigid insulation is not recommended for use 1150 under the slab, a different heating system should be used. 1151

machinery or


1152

1153 Figure 5-11. (EN12) Slab-on-grade floors, heated - heating elements either within (as shown) or 1154 below the slab. 1155

1156

EN-13 Doors - Opaque, Swinging (Climate Zones: all) 1157 A U-factor of 0.37 corresponds to an insulated double-panel metal door. A U-factor of 1158

0.61 corresponds to a double-panel metal door. If at all possible, single swinging doors should 1159 be used. Double swinging doors are difficult to seal at the center of the doors unless there is a 1160 center post. Double swinging doors without a center post should be minimized and limited to 1161 areas where width is important. Vestibules can be added to further improve the energy 1162 efficiency. 1163

1164


1166

EN-14 Doors - Opaque, Roll-up or Sliding (Climate Zones: all) 1167 Roll-up or sliding doors are recommended to have R-4.75 rigid insulation or meet the 1168

recommended U-factor. When meeting the recommended U-factor, the thermal bridging at the 1169 door and section edges is to be included in the analysis. Roll-up doors that have solar exposure 1170 should be painted with a reflective paint (or high emissivity) and/or should be shaded. Metal 1171 doors are a problem in that they typically have poor emissivity and collect heat which is 1172 transmitted through even the best insulated door causing cooling loads and thermal comfort 1173 issues in the space. 1174

1175

If at all possible use insulated panel doors over roll-up doors as the insulation values can 1176 approach R-10 and the provide a tighter seal to minimize infiltration. 1177

1178

Options 1179 1180

EN-15 Alternative Constructions (Climate Zones: all) 1181 The climate zone recommendations provide only one solution for upgrading the thermal 1182

performance of the envelope. Other constructions can be equally effective, but they are not 1183


shown in this document. Any alternative construction that is less than or equal to the U-factor, C-1184 factor, or F-factor for the appropriate climate zone construction is equally acceptable. A table of 1185 U-factors, C-factors, and F-factors that corresponds to all of the recommendations is presented in 1186 Appendix A. 1187

Procedures to calculate U-factors and C-factors are presented in the ASHRAE 1188 Handbook—Fundamentals, and expanded U-factor, C-factor, and F-factor tables are presented in 1189 Standard 90.1, Appendix A. 1190

1191

Cautions 1192 The design of building envelopes for durability, indoor environmental quality, and energy 1193

conservation should not create conditions of accelerated deterioration, reduced thermal 1194 performance, or problems associated with moisture and air infiltration. The following cautions 1195 should be incorporated into the design and construction of the building. 1196

EN-16 Heel Heights (Climate Zones: all) 1197 When insulation levels are increased in attic spaces, the heel height should be raised to 1198

avoid or at least minimize the eave compression. 1199

1200

EN-17 Slab Edge Insulation (Climate Zones: all) 1201 Use of slab edge insulation improves thermal performance, but problems can occur in 1202

regions of the country that have termites. 1203

EN-18 Air Infiltration Control (Climate Zones: all) 1204 • The building envelope should be designed and constructed with a continuous air barrier system 1205 to control air leakage into or out of the conditioned space. An air barrier system should also be 1206 provided for interior separations between conditioned space and space designed to maintain 1207 temperature or humidity levels that differ from those in the conditioned space by more than 50% 1208 of the difference between the conditioned space and design ambient conditions. The air barrier 1209 system should have the following characteristics: 1210

• It should be continuous, with all joints made airtight. 1211

• Air barrier materials used in frame walls should have an air permeability not to exceed 0.004 1212 cfm/ft2 under a pressure differential of 0.3 in. water (1.57 lb/ft2) when tested in accordance with 1213 ASTM E 2178. 1214

• The system is capable of withstanding positive and negative combined design wind, fan, and 1215 stack pressures on the envelope without damage or displacement and should transfer the load to 1216 the structure. It should not displace adjacent materials under full load. 1217

• It is durable or maintainable. 1218

• The air barrier material of an envelope assembly should be joined in an airtight and flexible 1219 manner to the air barrier material of adjacent assemblies, allowing for the relative movement of 1220 these assemblies and components due to thermal and moisture variations, creep, and structural 1221 deflection. 1222

1223

• Connections should be made between: 1224


(a) Foundation and walls. 1225

(b) Walls and windows or doors. 1226

(c) Different wall systems. 1227

(d) Wall and roof. 1228

(e) Wall and roof over unconditioned space. 1229

(f) Walls, floor, and roof across construction, control, and expansion joints. 1230

(g) Walls, floors, and roof to utility, pipe, and duct penetrations. 1231

1232

All penetrations of the air barrier system and paths of air infiltration/exfiltration should 1233 be made airtight. 1234

Vertical Glazing 1235

Good Design Practice 1236

EN-19 Vertical Fenestration Descriptions (Climate Zones: all) 1237 The recommendations for vertical windows are listed in Section 3 by climate zone. Table 5-2 1238 below shows the type of window construction that generally corresponds to the U-factor 1239 specifications in the Section 3 Recommendation Tables. 1240

1241

Table 5-2 Vertical Fenestration Descriptions 1242

U-factor SHGC VLT Description

0.56 0.25 0.37 Metal frame with a Thermal Break

Clear Glass with Medium Performance Reflective Coating

Insulated Spacers between Panes

Low-e Coated Glass

0.44 0.46 0.62 Metal Frame with a Thermal Break

Clear Glass


Low-e Coated Glass

0.38 0.41 0.60 Vinyl Frame

Clear Glass


Low-e Coated Glass

1243

To be useful and consistent, the U-factors for windows should be measured over the entire 1244 window assembly, not just the center of glass. Look for a label that denotes the window rating is 1245 certified by the National Fenestration Rating Council (NFRC). The selection of high-1246


performance window products should be considered separately for each orientation of the 1247 building and for daylighting and viewing functions. 1248

EN-20 Fenestration to Gross Wall Area Ratio (FWR) (Climate Zones: all) 1249 The fenestration to gross wall area ratio (FWR) is the percentage resulting from dividing the total 1250 vertical fenestration area by the total exterior wall area. The FWR includes both the view 1251 fenestration below 7’ and the daylighting fenestration above 7’. The FWR for all surfaces of the 1252 school should not exceed 35%. A reduction in the view fenestration will also save energy, 1253 especially if glazing is significantly reduced on the east and west facades. The smallest glazed 1254 area should be designed that is still consistent with needs for view, daylighting, and passive solar 1255 strategies. 1256

Window Design Guidelines for Thermal Conditions 1257 Uncontrolled solar heat gain is a major cause of energy consumption for cooling in warmer 1258 climates and thermal discomfort for occupants. Appropriate configuration of windows according 1259 to the orientation of the wall on which they are placed can significantly reduce these problems. 1260

EN-21 Unwanted solar heat gain is most effectively controlled on the outside of the 1261 building (Climate Zones: all) 1262 Significantly greater energy savings are realized when 1263 sun penetration is blocked before entering the windows. 1264 Horizontal overhangs located at the top of the windows 1265 are most effective for south facing facades, and must 1266 continue beyond the width of the windows to adequately 1267 shade them. See Figure 5-14. Vertical fins can be 1268 problematic in schools from the perspective of 1269 vandalism). Consider louvered or perforated sun control 1270 devices, especially in primarily overcast and colder 1271 climates, to prevent a totally dark appearance in those 1272 environments. 1273

EN-22 Operable versus Fixed Windows (Climate 1274 Zones: all) 1275 Operable windows offer the advantage of personal 1276 comfort control and beneficial connections to the 1277 environment. However, individual operation of the 1278 windows not in coordination with the HVAC system 1279 settings and requirements can have extreme impacts on 1280 the energy use of a building’s system. Advanced energy buildings with operable windows 1281 should strive for a high level of integration between envelope and HVAC system design. First, 1282 the envelope should be designed to take advantage of natural ventilation with well placed 1283 operable openings. Second, the mechanical system should employ interlocks on operable 1284 windows to insure that the HVAC system responds by shutting down in the affected zone if the 1285 window is opened. It is important to design the window interlock zones to correspond as closely 1286 as possible to the HVAC zone affected by the open window. See HV-31 for more information. 1287

Figure 5-14


Warm Climates:

EN-23 Building Form and Window Orientation (Climate Zones: 1,2,3,4) In warm climates, north and south view glass can be more easily shielded and can result in less solar heat gain and less glare than do east and west facing glass. During site selection, preference should be given to sites that permit elongating the building in the east-west direction and that permit orienting more windows to the north and south. See Figure 5-15. A good design strategy avoids areas of glass that do not contribute to the view from the building or to the daylighting of the space. If possible, configure the building to maximize north facing walls and glass by elongating the floor plan. Since sun control devices are less effective on the East and West facades, the solar penetration through the East and West facing

glazing should be minimized. This can be done by reducing the area of glazing or, if the glass is 1306 needed for view or egress, by reducing the SHGC. Thus, the area of glazing on the East and 1307 West facades, times their respective SHGCs, must be less than the area of glazing on the North 1308 and South facades times their respective SHGCs. If each façade has a different area or SHGC, 1309 the formula becomes: ((W window area * W SHGC) + (E window area * E SHGC)) < (less than) 1310 ((N window area * N SHGC) + (S window area * S SHGC)). For buildings where a 1311 predominantly East-West exposure is unavoidable, or if the application of this equations would 1312 result in SHGCs of less than 0.25, then more aggressive energy conservation measures may be 1313 required in other building components to achieve an overall 30% energy savings. 1314 1315

EN-24 Glazing (Climate Zones: 1,2,3,4) 1316 For north and south facing windows, select windows with a low solar heat gain coefficient and 1317 an appropriate visible light transmission (VLT), see EN-19. Certain window coatings, called 1318 selective low-e, transmit the visible portions of the solar spectrum selectively, rejecting the non-1319 visible infra-red sections. These glass and coating selections can provide a balance between 1320 visible light transmission and solar heat gain. Window manufacturers market special "solar low-1321 e" windows for warm climates. For buildings in warm climates that do not utilize a daylight 1322 design, north and south window glazing should be selected with a solar heat gain coefficient 1323 (SHGC) of no more than 0.35. East and west facing windows in warm climates should be 1324 selected for an SHGC of no more than 0.25. All values are for the entire fenestration assembly, 1325 in compliance with NFRC procedures, and are not simply center-of-glass values. For warm 1326 climates, a low SHGC is much more important for low building energy consumption than the 1327 window assembly U-factor. Windows with low SHGC values will tend to have a low center of 1328 glass U-factor, however, because they are designed to reduce the conduction of the solar heat 1329 gain absorbed on the outer light of glass through to the inside of the window. 1330

EN-25 Obstructions and Planting (Climate Zones: all) 1331 Adjacent taller buildings, and trees, shrubs, or other plantings are effective to shade glass on 1332 south, east and west facades. For south facing windows, remember that the sun is higher in the 1333

1288

1289

1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 Figure 5-15


sky during the summer, so that shading plants should be located high above the windows to 1334 effectively shade the glass. The glazing of fully shaded windows can be selected with higher 1335 SHGC ratings without increasing energy consumption. The solar reflections from adjacent 1336 building with reflective surfaces (metal, windows or especially reflective curtain walls) should 1337 be considered in the design. Such reflections may modify shading strategies, especially on the 1338 north façade 1339

Cold Climates: 1340

EN-26 Window Orientation (Climate Zones: 5, 6, 7,8) 1341 Only the south glass receives much sunlight during the cold winter months. If possible, 1342 maximize south facing windows by elongating the floor plan in the east-west direction and 1343 relocate windows to the south face. By facing the glazing south and placing it vertical, it is easy 1344 to implement overhangs and simple sun control devices that allow for passive heating when 1345 desired but prevent unwanted glare and solar overheating in the warmer months. Glass facing 1346 east and west should be significantly limited. Areas of glazing facing north should be optimized 1347 for daylighting and view. During site selection, preference should be given to sites that permit 1348 elongating the building in the east-west direction and that permit orienting more windows to the 1349 south. See Figure 5-15. 1350

EN-27 Passive Solar (Climate Zones: 5, 6, 7,8) 1351 Passive solar energy saving strategies should be limited to non-classrooms or office spaces, such 1352 as lobbies and circulation, unless those strategies are designed so that the occupants are not 1353 effected by direct beam radiation. The solar radiation must be diffused as it enters into the 1354 classrooms. Consider heat absorbing blinds, blinds in the fenestration, light shelves, or diffusing 1355 films. In spaces where glare is not an issue, the usefulness of the solar heat gain collected by 1356 these windows can be increased by using hard massive floor surfaces, such as tile or concrete in 1357 the locations where the transmitted sunlight will fall. These floor surfaces absorb the transmitted 1358 solar heat gain and release it slowly over time, to provide a more gradual heating of the structure. 1359 Consider higher SHGC glazing (clear glass) with optimally designed exterior overhangs. 1360

EN-28 Glazing (Climate Zones: 5, 6, 7,8) 1361 Higher SHGC are allowed in colder regions, but continuous horizontal overhangs are still 1362 necessary to block the high summer sun angles. 1363

1364

Lighting and Daylighting 1365 Electric lighting is one of the largest energy users in schools. Depending on climate, lighting 1366 energy use can be as high as about 40% of the total energy use of a basic, energy-code compliant 1367 school. Because lighting-related improvements can be inexpensive and offer rapid payback, they 1368 are at the top of the list of recommendations towards meeting an overall target of 30% better 1369 efficiency or better. 1370

There are two distinctly different approaches to reducing electric lighting power – either can be 1371 used to meet the recommendations in Chapter 3: 1372

• Designing a daylit school. Vertical fenestration and skylights can provide appropriate 1373 interior illumination without excessive solar heat gain. Electric lighting systems can then 1374 be extinguished or dimmed for most school hours, saving significant energy and 1375 maintenance costs. The key to daylighting is integrated design in which HVAC and 1376


electric lighting controls are optimized to take full advantage of and “harvest” energy 1377 savings, and added first costs of fenestration are offset by reduced costs in HVAC. 1378 Because of daylighting’s additional non-energy benefits, a design employing daylighting 1379 should be pursued whenever possible. See the How-To Implement the daylighting 1380 recommendations in DL-1 – DL-35. 1381

• Designing electric lighting using efficient and state of the art products and techniques. 1382 Unfortunately, proper daylighting design requires an integrated approach and appropriate 1383 design skills. If these are possible, predictable and persisting lighting energy savings of 1384 up to 43% can be achieved using appropriate lighting design. However, daylighting 1385 solutions may not always be possible in some schools due to site constraints or program 1386 requirements. Therefore, a non-daylit path is provided to meet the recommendations in 1387 Chapter 3. Because lighting energy savings also produce cooling savings, HVAC energy 1388 savings of 10-15% are also possible in cooling climates. Moreover, while the cost of 1389 high performance lighting may be about the same or more than a basic solution, the cost 1390 of HVAC capacity can also be reduced. See How-To Recommendations in EL-1 – EL-8. 1391

1392

General Lighting 1393

EL-1 Linear Fluorescent Lamps and Ballasts (Climate Zones: all) 1394 To achieve the LPD recommendations in Chapter 3, high-performance T-8 lamps and high-1395 performance electronic ballasts are used for general lighting. The use of standard T-8 and 1396 energy-saving T-8 lamps may also be considered but may result in lower ambient light levels or 1397 an increased number of fixtures or lamps to achieve recommended light levels. 1398

High-performance T-8 lamps are defined, for the purpose of this Guide, as having a lamp 1399 efficacy of 95+ nominal lumens per watt, based on mean lumens divided by the cataloged lamp 1400 input watts. Mean lumens are published in the lamp catalogs as the degraded lumen output 1401 occurring at 40% of the lamp’s rated life. High-performance T-8s also are defined as having a 1402 CRI of 81 or higher and 94% lumen maintenance. The higher performance is achieved either 1403 by increasing the output (3100 lumens) while keeping the same 32 W input as standard T-8s or 1404 by reducing the wattage while keeping the light output similar to standard T-8s (e.g., 2750 1405 lumens for 28 W or 2850 lumens for 30 W). 1406

High-performance electronic ballasts are defined, for the purpose of this Guide, as two-lamp 1407 ballasts using 55 W or less with a ballast factor (BF) of 0.87 or greater. One-lamp, three-lamp 1408 and four-lamp ballasts may be used but should have the same or better efficiency as the two-1409 lamp ballast. Dimming ballasts do not need to meet this requirement. The higher output 3100 1410 lumen lamps are visibly brighter than standard T-8s. Using ballasts with a BF of 0.77 may 1411 provide more comfortable lamp brightness, in direct luminaires where the lamp is visible, 1412 without sacrificing efficiency. 1413

Program start ballasts are recommended on frequently switched lamps (switched on and off 1414 more than five times a day) because they greatly extend lamp life over frequently switched 1415 instant start ballasts. 1416

Instant start T-8 ballasts typically provide greater energy savings and are the least costly option; 1417 also, the parallel operation allows one lamp to operate even if the other burns out. However, 1418 instant start ballasts may reduce lamp life, especially when controlled by occupancy sensors or 1419 daylight switching systems. 1420

T-5 ballasts should always be program start. 1421


EL-2 Fluorescent T-5 Sources (Climate Zones: all) 1422 To achieve the LPD recommendations in Chapter 3 for the non-daylit option, T-5HO and T-5 1423 lamps may be part of the solution. They have initial lumens per watt that compare favorably to 1424 the high-performance T-8s. In addition to energy, T-5s use fewer natural resources (glass, metal, 1425 phosphors) than comparable lumen output T-8 systems. However, when evaluating the lamp and 1426 ballast as a system (at the mean lumens of the lamps), high-performance T-8 systems perform 1427 better than T-5HO systems. In addition, T-5s have higher surface brightness and should not be 1428 used in open-bottom fixtures. It may be possible to achieve the base LPD while maintaining the 1429 desired light levels using T-5 fixtures as the primary light source if careful selection of the 1430 fixture reduces direct glare from the lamp. 1431

EL-3 Compact Fluorescent (Climate Zones: all) 1432 To achieve the LPD recommendations in Chapter 3, compact fluorescent lamps may be used for 1433 general ambient lighting and wall-washing. Compact fluorescent lamps are defined, for the 1434 purpose of this Guide, as having a lamp efficacy of 55+ nominal lumens per watt, based on mean 1435 lumens divided by the cataloged lamp input watts, and a CRI of 82 or greater. Use electronic 1436 ballasts on all compact fluorescent lighting. 1437

EL-4 Ceramic Metal Halide (Climate Zones: all) 1438 To achieve the LPD recommendations in Chapter 3, ceramic metal halide (CMH) lamps may be 1439 used for general ambient, accent lighting, and wall-washing. CMH lamps are defined, for the 1440 purpose of this Guide, as having a lamp efficacy of 50+ nominal mean lumens per watt and a 1441 CRI of 81 or greater. Use electronic ballasts on all CMH lighting. 1442

EL-5 Occupancy Sensors (Climate Zones: all) 1443 Use occupancy sensors in all classrooms, corridors, mechanical rooms, bathrooms, and offices. 1444 The greatest energy savings are achieved with manual on/automatic off occupancy sensors if 1445 daylight is present. This avoids unnecessary operation when electric lights are not needed and 1446 greatly reduces the frequency of switching. In non-daylit areas, ceiling-mounted occupancy 1447 sensors are preferred. In every application it should not be possible for the occupant to override 1448 the automatic OFF setting, even if set for manual ON. Unless otherwise recommended, factory-set 1449 occupancy sensors should be set for medium to high sensitivity and a 15-minute time delay (the 1450 optimum time to achieve energy savings without excessive loss of lamp life). Review 1451 manufacturer’s data for proper placement and coverage. 1452

The two primary types of occupancy sensors are infrared and ultrasonic. Infrared sensors can 1453 only see in a line-of-sight and should not be used in rooms where the user cannot see the sensor 1454 (e.g., storage areas with multiple aisles, restrooms with stalls). Ultrasonic sensors can be 1455 disrupted by high airflow and should not be used near air duct outlets. 1456

EL-6 Exit Signs (Climate Zones: all) 1457 Use LED exit signs or other sources that consume no more than 5 W per face. The selected exit 1458 sign and source should provide the proper luminance to meet all building and fire code 1459 requirements. 1460

EL-7 Circuiting and Switching (Climate Zones: all) 1461 Provide for multilevel switching in classrooms, with placement of switches near the door and 1462 near the teaching stations. See CHPS Guideline LG12: Lighting Controls for Classrooms. 1463 http://www.chps.net/manual/documents/BPM_2006_Edition/CHPS_II_2006_Lighting_and_Day1464 lighting.pdf 1465


EL-8 Electrical Lighting Design for Schools (Climate Zones: 1-4) 1466 The 0.9 W/ft2 recommendation for lighting power (shown in the Recommendation Tables in 1467 Chapter 3 for the non-daylit options in Climate Zones 1-4) represents an average LPD for the 1468 entire building. Individual spaces may have higher power densities if they are offset by lower 1469 power densities in other areas. The lighting power for the daylit options is 1.3 W/ft2. This 1470 lighting power is recommended for the daylit options because the lighting savings are a result of 1471 the lights dimming or turning off from the daylight- not an aggressive lighting power reduction. 1472 The lighting savings for the non-daylit option are a result of higher performance electrical 1473 lighting system. 1474

The CHPS Lighting and Daylighting Design Guidelines provide the following examples for 1475 meeting the 0.9 W/ft2 lighting power recommendations: 1476

• CHPS Guideline LG9: Classroom Lighting-Conventional Teaching 1477

• CHPS Guideline LG13: Gym Lighting. 1478

• CHPS Guideline LG14: Corridor Lighting. 1479

• CHPS Guideline LG16: Lighting for a Library or Media Center. 1480

• CHPS Guideline LG17: Lighting for Offices and Teacher Support Rooms. 1481

Each of these lighting guidelines can be reviewed at: 1482

http://www.chps.net/manual/documents/BPM_2006_Edition/CHPS_II_2006_Lighting_and_Day1483 lighting.pdf1484

1485

Daylighting 1486

DL-1 General Principles (Climate Zones: all) 1487 Daylighting is essential for a high performance school. Daylighting is when sunlight is used to 1488 offset electrical lighting loads. When properly designed, daylighting saves more in lighting 1489 loads and results in reduced cooling loads. 1490

In addition to energy benefits, a number of studies have shown that daylight can also help 1491 improve learning. One study shows that increases in test scores for elementary school students 1492 in classrooms with daylight and views are significantly higher than those without daylight2. 1493 Some of the gain in productivity may be due to the ability of daylight to reinforce our circadian 1494 rhythms, in addition to enabling students and teachers to perform visual tasks more efficiently. 1495 From a student and teacher productivity standpoint, classrooms are the most beneficial spaces to 1496 daylight; particularly special need classrooms. 1497

It is important that daylighting provide adequate and quality lighting. For daylighting to save 1498 energy, it must be “superior” to the electrical lighting. If not, the habit of walking into a space 1499 and turning on the lights will never be broken. Develop a daylighting strategy which will 1500 provide superior lighting for at least 50% of the hours of school operation. From an energy 1501 perspective, a daylighting strategy that is not quite good enough may not result in energy savings 1502 because the electric lights will not be turned off. 1503

If designed correctly, a daylighting strategy can reduce: 1504

2 http://www.h-m-g.com/projects/daylighting/projects-PIER.htm


• electricity for lighting and peak electrical demand; 1505

• cooling energy and peak cooling loads; and 1506

• maintenance costs associated with lamp replacement; 1507

Cooling loads can be reduced by providing just the right amount of daylighting in your school. 1508 Because the lights are out, internal gains are reduced. The lumens per watt (efficacy) of 1509 daylighting is higher than that of electric lighting sources. In other words, to meet the same 1510 lighting need, daylighting produces less heat. However, to achieve this reduced cooling it is 1511 essential that: 1512

• No more solar radiation is allowed to enter the building than is required to meet the 1513 lighting design criteria; 1514

• Overhangs and other shading devices are properly sized to control solar radiation; and 1515

• The electric lights, through the use of photosensors, are automatically dimmed or turned 1516 off. 1517

DL-2 Space Types (Climate Zones: all) 1518 Daylighting the classroom is most critical, since that is where the teachers and the students spend 1519 most of their time. In addition, the potential for savings is the greatest in the classrooms. 1520 Guidelines are also provided for the gymnasium/ multipurpose room because this space is 1521 typically used for more hours. While specific guidelines are not provided, daylighting should 1522 also be considered for the: 1523

• cafeteria, 1524

• media center, 1525

• administrative areas, and 1526

• corridors. 1527

DL-3 How to Select Daylighting Strategies (Climate Zones: all) 1528 For this Advanced Energy Design Guide, four daylighting strategies are presented: three for 1529 classrooms and one for gymnasiums. However, for each strategy, there are several options and 1530 variations depending on climate and orientation. These daylighting strategies are designed to 1531 provide all of the needed illuminance to the classrooms and gym over the majority of occupied 1532 daytime hours. 1533

These strategies are based on all classroom spaces being oriented either north or south. While 1534 daylighting can be achieved for other orientations, the recommendations in this document do not 1535 apply. These four patterns are summarized below, and more specific information is provided in 1536 DL-20 through DL-37. The table below summarizes the application criteria for each daylighting 1537 strategy. 1538

• Classrooms with sidelighting only. There are two variations of this for north facing and south 1539 facing classrooms. South facing classrooms are assumed to have overhangs and lightshelves 1540 to bounce the daylighting deeper into the space. 1541

• Classrooms with toplighting only. Only one option is provided for toplighting, which is a 1542 south facing roof monitor positioned in the center of the space and coupled with light baffles 1543 to bounce and filter light. 1544


• Classrooms with a combination of sidelighting and toplighting. This daylighting pattern 1545 combines the south or north facing classrooms described in the first bullet with top lighting at 1546 the back walls of the classrooms. The top lighting may be provided by either skylights or 1547 roof monitors depending on climate and other design constraints. 1548

• Gyms with toplighting. There are two variations of this daylighting pattern: roof monitors 1549 and skylights. 1550

Table—Application for Daylighting Strategies1551

Sidelit Classrooms Insert mini sketch

Toplit Classrooms Insert mini sketch

Sidelit and Toplit Classrooms

Insert mini sketch

Toplit Gym Insert mini sketch

Uniform Light Distribution Low Glare Top Floor/Single Story Middle/Ground Floors Reduced Energy Costs Low First Cost Cost Effectiveness Low Maintenance

Extremely good application Good application Poor application Extremely poor application / Mixed benefits 1552 1553

DL-4 Recommended Daylighting Fenestration to Floor Area Ratios (Climate Zones: all) 1554 For view and a positive connection to the out-of-doors, provide view windows below the 7’-0” 1555 height. East and west glass should be minimized and shading should be provided on the south 1556 side. North view glass need not be shaded. See EN-21 for more information. Glazing above 7 1557 feet is designed to provide daylighting, and should be sized according to the daylighting 1558 fenestration to floor area ratios (FFR) in the Table below. These basic rules-of-thumb that will 1559 help in determining the right amount of daylighting fenestration for particular systems. These 1560 numbers can be fine-tuned using daylighting analysis particular to the climate and the actual 1561 space configuration and use. These rules-of-thumb assume a VLT of the vertical daylighting 1562 fenestration of 65%-75%. For the horizontal daylighting fenestration (skylights), a 60% VLT is 1563 assumed. Further details on each daylighting strategy are provided in DL-20 through DL-37. 1564


Table- Daylighting Fenestration to Floor Area Ratios 1565

Daylighting Strategy Classroom Gymnasium/Multipurpose Room

South-facing roof monitor 8% to 11% 5% to 8%

North-facing roof monitor 12% to 15% 7% to 10%

South lightshelf 8% to 11%

South lightshelf w/blinds between glazing 15% to 20%

High, North glazing 15% to 20%

Skylights 4% to 5%

Tubular Daylighting Devices 2% to 4%

1566

DL-5 Separate View Windows from Daylighting Strategy (Climate Zones: all) 1567 In designing daylighting systems, it is important to separate the view glass from the daylighting 1568 glass. To maximize the energy efficiency, the daylighting glazing is sized and placed to provide 1569 good quality lighting to the space, independent of the view glass. Additional glazing can be 1570 added, but only for view glass. The larger the view glass, the worse the energy performance of 1571 the building. 1572

Windows both for view and for daylighting should only be located on the north and south 1573 facades. Glass on the east and west should be minimized as it causes excessive cooling loads 1574 and is not effective for heating because of the sun angles. 1575

Visual comfort is strongly affected by the window location, shading, and glazing materials. 1576 Well-designed windows can be a visual delight. But poorly designed windows can create a 1577 major source of glare. 1578

In schools, wall space is precious. As result, view glass windows often serve as display areas. 1579 Additionally, these windows are almost always accompanied by blinds that can readily be closed 1580 by the teachers and students. While view windows are recommended to provide a connection 1581 with the out-of-doors, they should not be considered as a contributor to daylighting. Even if they 1582 are not covered by artwork or blinds, they have limited benefit, lighting only the spaces very 1583 close to the window. Daylighting fenestration should only include that which is located above 1584 door height, about 7 ft. It is best to build the daylighting design around roof monitors; high, 1585 south-side light shelf apertures; or high, north glass transom windows. 1586

1587

DL-6 Lighting Design Criteria (Climate Zones: all) 1588 Design the daylighting system to provide enough, but not too much lighting. Classroom 1589 daylighting systems should be designed to meet the following criteria.3 1590

• 45 to 50 footcandles of average illumination for general instruction, 1591

• 30 footcandles on the teaching surface (non-A/V mode) with a uniformity not exceeded 8:1. 1592

3 See the Overview section of the Lighting and Daylighting chapter of the CHPS Best Practices Manual, 2006 Edition, pages 196-203, for more detail. See also the IESNA Handbook, ninth edition.


• 20 to 25 footcandles of average illumination for A/V mode, 1593

• Uniformity not to exceed 8:1, and 1594

• Glare not to exceed 20:1. 1595

The same criteria for lighting quality and quantity applies for both electric lighting and 1596 daylighting. When the criteria cannot be met with daylighting, electric lighting will meet the 1597 load. The objective is to maximize the daylighting and to minimize the eclectic lighting. To 1598 maximize the daylighting, without oversizing, can require in-depth analysis. 1599

For sunny climates, designs can be evaluated on a sunny day near the summer solstice. For more 1600 cloudy climates, a typical cloudy day should be used to evaluate the system—typically, the 1601 glazing to floor ratio percentage will increase for cloudy climates. Just because a school is in a 1602 cloudy climate, don’t think that daylighting will not work. Cloudy climates can produce diffuse 1603 skies, which create good daylighting conditions while minimizing glare and heat gain. 1604

1605

DL-7 Consider Daylight Early in the Design Process (Climate Zones: all) 1606 The most economic and effective daylighting strategies are ones that are very well integrated into 1607 the design from a structural, mechanical, electrical, and architectural standpoint. Daylighting is 1608 not as simple as it may appear. To do it well, the many different inter-related aspects of the 1609 school’s architecture, landscape, and engineering must be considered. Properly integrated, 1610 mechanical cooling equipment can be reduced because overall cooling loads are reduced. 1611 Design cooling loads should be calculated with the lights off allowing for the diffuse radiation 1612 that enters the space. This will allow for proper trade-offs between the daylighting and the sizing 1613 of the cooling system. 1614

If properly integrated, common architectural components may serve dual functions, reducing 1615 first cost. An example is that white single-ply roofing can serve both as a waterproofing 1616 membrane and at the same time it can increase radiation into a roof mounted daylighting 1617 aperture. Only a comprehensive, well thought out approach will provide a low cost system that 1618 achieves the desired benefits. 1619

The opposite is true without integrated design. If the daylighting system is designed and bid as 1620 an alternate, it is unlikely that the daylighting strategy will be nearly as cost effective or resource 1621 smart. The problem arises if the designers think that the daylighting components will have a 1622 good chance of being eliminated. Once the designer has this mindset, it is very unlikely that they 1623 will risk designing a smaller mechanical cooling system, thinking that they may have to redo the 1624 design at their cost. 1625

The best way to guarantee a low cost daylighting strategy is to fight against this instinct and 1626 integrate daylighting early in the schematic design phase. With good schematic design cost 1627 estimates that reflect the added daylighting components as well as the reduced cooling 1628 equipment and multi-use of building components, the designer will soon see that the “net” 1629 daylighting costs are very reasonable. 1630

DL-8 Use Daylighting Analysis Tools to Optimize Design (Climate Zones: all) 1631 Quality daylighting design requires that the specific conditions of each case be analyzed. It is 1632 recommended that a point-by-point model be used to analyze typical classroom daylighting 1633 patterns to assure that the design criteria are met. See CHPS Volume II, pages 205, 208 for a 1634 detailed description of available tools. At a minimum, daylighting should be evaluated for 1635 multiple design conditions, including sunny and cloudy conditions, the summer and winter 1636


solstice and the equinox, and three times during the day: 9:00 AM, noon and 3:00 PM. The 1637 analysis tool should have the capability of predicting illumination and surface brightness for a 1638 grid of points within the space and, be able to calculate performance during all hours of 1639 operation. 1640

Annual savings will have to be calculated with an annual whole building energy simulation tool 1641 with input from the daylighting analysis tool. The daylighting analysis tool will not help with 1642 heating and cooling loads or other energy uses. It only predicts illumination levels and perhaps 1643 electric lighting use. 1644

DL-9 Building Orientation (Climate Zones: all) 1645 Cost-effective daylighting starts with good orientation. For classrooms and most other spaces, 1646 the vertical facades that provide daylighting should be oriented within 15 degrees of either north 1647 or south. Sidelit daylighting solutions can be developed for other orientations, but they are 1648 beyond the recommendations provided in this document and typically are not as effective. 1649 Orientation is less important if toplighting is used as the primary daylighting pattern since roof 1650 monitors can be rotated on the roof. However, even with roof monitors, the main axis of the 1651 building should still be within 15 degrees of north/south or east/west. East and west glass is 1652 problematic from a solar heat gain perspective, and provides non-uniform daylighting. 1653

In integrating the building into the overall site, make sure that the daylighting apertures are not 1654 shaded by adjacent buildings, or trees, or elements of the school building itself (self shading). 1655

DL-10 Ceiling Height (Climate Zones: all) 1656 For all daylit classrooms, a minimum of 10 ft ceiling height is recommended, however when 1657 daylighting must be provided entirely from sidelighting, a greater ceiling height is recommended 1658 at the perimeter wall and it is desirable that the ceiling be sloped when this is possible. See DL-1659 26 for additional information. 1660

DL-11 Outdoor Surface Reflectance (Climate Zones: all) 1661 Consider the reflectance of the roofs, sidewalks and other surfaces in front of the glazing areas. 1662 The use of lighter roofing colors can increase daylighting concentration and in some cases reduce 1663 the glass area needed for roof monitors or clerestories. However, a light colored walkway in 1664 front of view windows should be considered carefully. While a light colored surface may 1665 improve daylighting, depending on the design of the façade, it may also cause unwanted 1666 reflections and/or glare. 1667

DL-12 Eliminate Direct Beam Radiation (Climate Zones: all) 1668

An essential component of any good daylit school design is the elimination of uncontrolled, 1669 direct beam radiation onto the work plane. This is critical for all classrooms, libraries or media 1670 centers, and administrative spaces, but less critical for some gymnasiums, multipurpose spaces 1671 and corridors. Use strategies that bounce, redirect, and/or filter sunlight so that direct radiation 1672 does not directly enter space. A good test is to evaluate sun angles at 9 AM, noon, and 3 PM on 1673 the equinox and at the summer solstice and make sure that there is no direct solar radiation on the 1674 work plane4 inside a band of 4 ft from the edges of the walls. If this criterion is met, then interior 1675 shades will be used unnecessary, except for possibly darkening the space for A/V purposes. 1676 With advances in A/V technology, including flat screens and LCD projectors, room darkening is 1677 not as important as it was in the past. 1678

4 Typically, a surface 30” above the floor. Maybe less for lower elementary grades.


The purpose of shading is to prevent direct solar penetration into the space, which can be a 1679 source of glare and excess heat gain. There are various types of shading strategies. They should 1680 be implemented in the order that they are listed below: 1681

• External shading: methods which prevent direct sun from reaching the glazing. These 1682 include major building and architectural elements, such as overhangs, soffits, trellises, 1683 awnings and light shelves. This method is the most effective, as it prevents both excess solar 1684 heat gain and glare. 1685

• Shading integral with the glazing: methods in which the glazing itself rejects unwanted solar 1686 gain, including characteristics of glazing including coloration (absorption), reflectivity, and 1687 selective transmission; opaque elements integral to the glazing itself, such as ceramic frit 1688 patterns or integrated photovoltaics; or the use of baffles or blinds between glazing panels. 1689

• Internal shading: methods for rejecting solar gain that has already entered the space, 1690 including baffles, louvers rolling shades, blinds, and internal overhangs. Note that internal 1691 shading can be vertically mounted for a window or mounted in other planes, such as skylight 1692 wells. 1693

The success of daylit schools depends on how occupants interact with the daylighting system. 1694 This is particularly true for blinds or shades which are available for adjustment by occupants. 1695 Occupants are motivated to close the blinds but not toe reopen them. Occupants adjust blinds on 1696 a long term basis. If blinds are left closed, the daylighting potential will not be realized. If 1697 temporarily darkening of a specific space it is not required functionally, don’t install shades or 1698 blinds on the daylighting glass. The implementation of unnecessary blinds will result in reduced 1699 performance, increased first costs, and greater long-term maintenance expenses. 1700

DL-13 Daylighting Control for A/V Activities (Climate Zones: all) 1701 If a classroom requires darkening for A/V or other functions, consider motorized roller shades or 1702 motorized vertical blinds for apertures that are out of reach. It may seem like this will result in 1703 higher maintenance costs, but such controls can have the opposite effect. The mechanical stress 1704 placed on manual operators by the students and teachers (do to uneven cranking) limits the 1705 effective life of these devices to under ten years. The inconvenience associated with the process 1706 also results in a number of these shades being left closed. Motorized shades, while they cost 1707 more upfront, will provide operators with greater ease of operation and result in a better 1708 performing daylighting design. Some motorized devices can also be programmed to reset in the 1709 open position at the beginning of each day. 1710

Some teachers still use overhead projectors, but most use TV monitors or LCD projectors. All of 1711 these teaching tools require that the light level at the specific location of the screen be kept below 1712 seven footcandles. 1713

As an option to shading the daylighting apertures, consider the option of locating the screen or 1714 monitor in a portion of the room that has less daylight. However, the TV monitor should be 1715 placed in a location that does not produce glare on the screen. This is typically easy to 1716 accomplish by locating the TV monitor high, in a corner of the space and not adjacent to or 1717 facing a window. 1718

White boards need sufficient light (about 30 footcandles) with a uniformity not exceeded 8:1. 1719 White boards have a specular surface and should be carefully located so that there is no 1720 reflecting glare from either daylighting apertures or lighting fixture. Since the whiteboard is 1721 typically in the same location as the overhead projection screen, separate control of the teaching 1722 surface light is essential. To address both of these needs, the designer needs to intentionally 1723


darken the area of the teaching wall that has the screen and then use electric lighting to enhance 1724 the wall when the white board is used. 1725

DL-14 Interior Finishes (Climate Zones: all) 1726 Select light colors for interior walls and ceilings to increase light reflectance and reduce lighting 1727 and daylighting requirements. Minimum surfaces reflectances are shown in the table below. 1728 The color of the ceiling, walls, floor, and furniture have a major impact on the effectiveness of 1729 the daylighting strategy. When considering finish surfaces, install light colors (white is best) to 1730 insure that the daylight is reflected throughout the space. 1731

Consider a ceiling tile or surface that has a high reflectivity. Make sure that fissures within 1732 acoustical tiles and how this will impact the amount absorbed. Don’t assume that the color of a 1733 tile alone dictates its reflectance. When selecting a tile, specify a minimum reflectivity. Most 1734 manufactures will list the reflectance as if it were the paint color reflectance. The Cx provider 1735 should verify the reflectance. 1736

Table. Minimum Reflectance 1737 Location Minimum Reflectivity

Walls above 7’ 80%

Ceiling 80%

Light wells 80%

Floors 30%

Furniture 50%

Walls below 7’ 50%

1738

DL-15 Calibration and Commissioning (Climate Zones: all) 1739 Even a few days of occupancy with poorly calibrated controls can lead to permanent overriding 1740 of the system and loss of savings. All lighting controls must be calibrated and commissioned 1741 after the finishes are completed and the furnishing are in place. Most photosensors require 1742 daytime and nighttime calibration sessions. The photosensor manufacturer and the QA provider 1743 should be involved in the calibration. Document the calibration and Cx settings and plan for 1744 future recalibration as part of the school maintenance program. 1745

DL-16 Dimming Controls (Climate Zones: all) 1746 For the classroom and gym daylit options, daylighting controls are recommended in all 1747 classrooms spaces and gyms/multipurpose spaces. For the non-daylit option, daylighting 1748 controls are still recommended for all zones within 15’ of a sidelit edge or within 10’ of a toplit 1749 edge. 1750

In all regularly occupied daylit spaces such as classrooms, gyms, and offices, continuously dim 1751 rather than switch electric lights in response to daylight, to minimize occupant distraction. 1752 Specify dimming ballasts that dim down to at least 20% of full output, with the ability to turn off 1753 when daylit provides sufficient illuminance. Provide a means and convenient location to 1754 override daylighting controls in spaces that are intentionally darkened to use overhead projectors 1755 or slides. The daylighting control system and /or photosensor should include a 5-minute time 1756 delay or other means to avoid cycling caused by rapidly changing sky conditions, and a one 1757 minute fade rate to change the light levels by dimming. Automatic multi-level daylight 1758


switching may be used in non-regularly occupied environments like hallways, storage, 1759 restrooms, lounges, lobbies, etc. 1760

DL-17 Photosensor Placement (Climate Zones: all) 1761 Correct photosensor placement is essential: Consult daylighting references or work with 1762 photosensor manufacturer for proper location. Mount the photosensors in a location that closely 1763 simulates the light level (or can be set by being proportional to the light level) at the work plane. 1764 Depending upon the daylighting strategy employed, photo sensor controls should be used to dim 1765 particular logical groupings of lights. Implement a lighting fixture layout and control wiring 1766 plan that complements the daylighting strategy. In sidelit classrooms, locate luminaires in rows 1767 parallel to the window wall, and wire each row separately. Because of the strong difference in 1768 light that will occur close to the window and back further from the window, having this 1769 individual control by bank will help balance out the space . In a space that has a roof monitor, 1770 install a photosensor that controls all the perimeter lights and a second that controls all the lights 1771 within the monitor well. In gymnasiums, ganged fluorescent fixtures coupled with dimmable 1772 ballasts are a great way of eliminating the problems typically associated with using metal halide 1773 fixtures (long-restrike time). 1774

DL-18 Photosensor specifications (Climate Zones: all) 1775 Photosensors used for classrooms should be specified for the appropriate illuminance range 1776 (indoor or outdoor) and must achieve a slow, smooth linear dimming response from the dimming 1777 ballasts. A closed loop system is one in which the interior photocell responds to the combination 1778 of daylight and electric light in the daylit area. The best location for the photocell is above an 1779 unobstructed location such as the middle of the classroom. If using a lighting system that 1780 provides an indirect component, mount the photosensor at the same height as the luminaire or in 1781 a location that is not impacted by the uplight from the luminaire. 1782

An open loop system is one in which the photocell responds only to daylight levels but is still 1783 calibrated to the desired light level received on the work surface. The best location for the photo 1784 sensor is inside the skylight/roof monitor well. 1785

DL-19 Select compatible light fixtures (Climate Zones: all) 1786 First consider the use of indirect lighting fixtures that more closely represents the same effect as 1787 daylighting (the light is not as much coming from a single source but is, do to the multiple 1788 reflections) more uniform and has less glare. 1789

In addition, insist on compatibility between ballast, lamps, and controls. Ensure that the lamps 1790 can be deep dimmed without sacrificing lamp life. 1791

Classroom Sidelighting 1792

The sidelighting patterns shown in Figure 1 are appropriate for either south facing or north 1793 facing classrooms, within 15 degrees of true. Sidelighting strategies can be used in classrooms 1794 on any floor of the school- they are not limited to the top floor. DL-20 through DL-27 provides 1795

1796 further information on sidelighting strategies.


1797 Figure 1 – Classroom Sidelighting 1798

1799 DL-20 South Facing Classrooms- Configuration of Apertures (Climate Zones: all) 1800 The choice of fenestration and the placement of the apertures are critical. If uncontrolled, direct 1801 beam radiation enters the classroom window, it can create glare and the teacher will simply close 1802 the blinds and negate your daylighting strategy all together. 1803

A light shelf is recommended for south facing daylight walls. The windows above the light shelf 1804 should be as continuous as possible, with the height of the daylighting window typically 4 feet to 1805 5 feet high. The window should be positioned as close to the ceiling as possible, within structural 1806 constraints. 1807

An overhang should be positioned over the daylighting aperture and sized with the light shelf to 1808 prevent direct sun from entering the space. Set the cutoff angle of the light shelf or louvers (see 1809 the figure below) to eliminate direct sun penetration during normal school hours. If there are 1810 operable shades on the upper glazing that are seasonally adjusted, the cut off angle may be 1811 increased by 20°. 1812

1813 Figure 2 – 1814

An option to the light shelf would be to add mini blinds between the panes of glass and, in cold 1815 climates, add a third pane. In this case, the interior portion of the light shelf may be eliminated, 1816 but the outer portion is still needed to shade the vision glass. 1817


1818

1819 Figure 3 – Light Shelf Details 1820

1821

For north facing classrooms, a light shelf is not needed because its benefits are related to the 1822 reflection of direct solar and north facades do not experience much direct solar gain. 1823

DL-21 South Facing Classrooms - Glazing Area and Fenestration Type (Climate Zones: all) 1824 The area of the daylighting aperture should be in the range of 80 ft² to 110 ft² for a typical 1,000 1825 ft² classroom. This recommendation is based on glazing with a light transmission of 65% to 1826 75%. Glazing with a lower light transmission may be used, but the aperture should be increased 1827 to maintain the same visible aperture. Where windows are used specifically for daylighting, 1828 consider the use of uncoated clear glass or low-e coated clear glass with a high VLT. A larger 1829 daylighting aperture with a lower VLT has the advantage of providing the same amount of 1830 daylight but with less glare and contrast. The disadvantage is typically the costs associated with 1831 all the components of the daylighting system are higher. 1832

The view windows below 7 feet do not require high light transmission glazing and values 1833 between 0.35 and 0.50 are good. Higher VLTs are preferred in predominantly overcast climates. 1834 VLTs below 0.35 may appear noticeably tinted and dim to occupants, and may degrade luminous 1835 quality and views. However, lower VLTs should be used for higher fenestration to wall ratios 1836 (FWR). Lower VLTs may also be appropriate for other conditions of low sun angles or light 1837 colored ground cover. 1838

Thermal comfort can also be compromised by poor fenestration choice, especially for the view 1839 glazing, which is in closer proximity to occupants. Poorly insulated windows add to a winter 1840 chill or summer sweat, while windows with low U-values keep glass surface temperatures closer 1841


to the interior air temperature, improving thermal comfort. In addition, east-west windows and 1842 un-shaded south windows (if they can’t be avoided) can cause excessive cooling loads. 1843

In all cases, windows should be made of high-quality construction, incorporate thermal breaks, 1844 and include the appropriate glazing for the particular application. 1845

Carefully consider the visible light, solar transmission, and insulation qualities of the particular 1846 daylighting glazing system under consideration, with particular emphasis on how much 1847 additional glazing will be needed to achieve the same visible light transmission. If the design is 1848 to effectively address energy at the same time creating a good daylighting strategy, it will be 1849 important to minimize the size and maximize transmission of daylighting apertures. 1850

The desirable color qualities of daylighting are best transmitted by neutrally-colored tints that 1851 alter the color spectrum to the smallest extent. In particular, avoid dark green and bronze colored 1852 glazing. To the greatest extent possible, avoid the use of reflective glass or low-e coatings with a 1853 highly reflective component, even for view glass. These reduce the quality of the view and the 1854

DL-22 South Facing Classrooms - Make Light Shelf Durable and Reflective (Climate 1855 Zones: all) 1856 Select durable materials for both interior and exterior lightshelves and, if reachable, design them 1857 to be capable of carrying the weight of a person. Aluminum exterior lightshelves are a good 1858 compromise between good reflectance and little or no maintenance, and cost. Incorporate white 1859 painted gypsum board on top of interior lightshelves. However, aluminized, acrylic sheets 1860 applied to the top of the interior shelf allows light to bounce further back into spaces and can 1861 improve performance in deeper rooms without top lighting. 1862

DL-23 South Facing Classrooms - Horizontal Blinds between Glazing (Climate Zones: all) 1863 As an alternative to an interior light shelves, consider horizontal blinds located between glazing. 1864 For the horizontal blinds to be effective they should be highly reflective and have either flat or 1865 curved blades. If curved, they should be turned opposite how they are normally installed, curved 1866 upward. Because of potential dirt build-up and maintenance, they should be placed between 1867 panes of glazing. 1868

If this option is used, consider the transmission of the blinds and increase the glazing area 1869 accordingly. 1870

Most of the shades that are available today are operable and have the opportunity to be closed if 1871 desired. However, if the space does not need to be temporarily darkened, the angle of the 1872 internal blinds should be fixed, angled up to the ceiling by the recommended cutoff angle for 1873 light shelves. By fixing the angle and not allowing the occupants to operate the blinds, there will 1874 less opportunity to override the daylighting benefits. If the internal blinds do need to be operated 1875 for darkening purposes, it is desirable to have two fixed positions: the one described above and a 1876 second “closed” position. 1877

DL-24 North Facing Classroom - Configuration of Apertures (Climate Zones: all) 1878 The window should extend to the ceiling or as close as possible. Window area below door height 1879 of about 7 ft should be considered as view glazing and not considered as a contributor to 1880 daylight. The daylighting glazing should be as continuous as possible along the façade. If it is not 1881 possible to provide continuous fenestration because of structural or other reasons, the windows 1882 should be placed in the corners of the space with the opaque wall for shear or structure located in 1883 the center of the wall. This will light the walls perpendicular to the daylighting wall and provide 1884 better uniformity and surface brightness. 1885


From a daylighting perspective, high, north glazing can provide a good daylighting option for a 1886 distance equal to 1.5 to 2.0 times the height of the window head. Like north-facing roof 1887 monitors, to achieve the same annual contribution, it takes more glazing than would a south 1888 lightshelf, hence the energy performance is not quite as good. The most significant advantage is 1889 that controlling direct beam radiation is not usually a problem. 1890

Often, when implementing a daylighting strategy in classrooms that face both north and south, 1891 you are faced with a challenge of establishing a common ceiling height. On the south side, you 1892 can use lightshelves that generally require less glazing than high, north transom apertures, unless 1893 you use blinds-between-the-glass or a south facing fenestration with a lower VLT, in which case 1894 the height of the south aperture will pretty closely match the height of north transom glazing. To 1895 maintain a common ceiling height, you may choose to consider some of the lower view glass on 1896 the north as an integral part of your daylighting strategy. Because of the fact that blinds would 1897 typically not be needed on the north to block direct beam radiation, it is logical to include some 1898 lower view glass. The big drawback is that the window area could still be used as a display 1899 board, in turn blocking the light. 1900

DL-25 North Facing Classroom - Glazing Area and Fenestration Type (Climate Zones: all) 1901 For glazing with a visible transmission of 65% to 75%, an area of 150 ft2 to 200 ft2 is 1902 recommended for a typical 1,000 ft2 classroom. If glazing with a lower VLT is used, then the 1903 area should be increased accordingly. Because of the lack of direct beam radiation on the north, 1904 lightshelves do not provide any benefit and should not be used. Assuming that lower north side 1905 view glass is considered in your daylighting strategy, it would be advisable, because of comfort, 1906 to utilize low-E glass in this case, sacrificing the 10% to 20% reduction in visible light benefit. 1907

DL-26 South and North Facing Classrooms - Sloped Ceilings (Climate Zones: all) 1908 When daylight can only be provided from the side, it is recommended that the ceiling be sloped 1909 to the back wall. A sloped ceiling can achieve a higher window head which will result in greater 1910 daylighting penetration into the space. The sloped ceiling will also provide a brighter ceiling. 1911

By sloping the ceiling from the outside wall to the back of the space it is often possible to 1912 encroach into the ceiling cavity space just at the window area, not increase floor-to-floor 1913 dimensions, and still have enough space for ductwork. 1914

mirrored effect is unpleasant to occupants after dark. 1915

DL-27 South and North Facing Classrooms - Recognize the Limits of Side Daylighting 1916 (Climate Zones: all) 1917 Sidelighting is an effective strategy for daylighting spaces in rooms with tall ceilings. For rooms 1918 with low ceilings, effective daylight can only be provided for spaces within 15 to 20 feet from 1919 the window. To daylight the whole classroom, consider wall washing skylights or roof monitors 1920 to supplement the sidelight. 1921

Classroom Toplighting 1922 One daylighting pattern is provided in this guide for toplighting. Other options exist that may be 1923 explored for specific school applications, however, they are beyond the scope of this document. 1924

Roof monitors, incorporating vertical south glazing and properly sized overhangs and interior 1925 baffles, have the following advantages. They: 1926

• create a very uniform lighting throughout the space; 1927

• can be used to daylight spaces far from the perimeter of the building; 1928


• create passive heating benefits, allowing more radiation to enter the space in the colder 1929 months; 1930

• create a more diffuse, filtered lighting strategy; and 1931

• reduce glare and contrast. 1932

The limitation of roof monitors is that they can only be employed in single story designs or to the 1933 top floors of multi-story designs. 1934

South Facing Roof Monitors

Overhand for Shade in Summer

White Reflective Surfaces (80%+)

Translucent White Fabric Baffles Placed to Block all Direct Beam Radiation

(fire-retardant, UV-resistant)

High VLT Glazing (70% +)

Use Light Colored Roof

In Front of Monitor

Allow Heat to Stratify. Do Not Locate Supply or Return In Monitor

White Reflective Walls Above 7' (80%+)South North

1935 Figure 4 – Classroom Toplighting 1936

1937

DL-28 Sizing the Roof Monitors (Climate Zones: all) 1938 For a 1000 ft2 classroom, the well opening of the roof monitors should be approximately 20 ft by 1939 20 ft. For sizing the south facing glazing in the monitor, the key is to size it to provide the 1940 desired level of daylighting illumination at the summer solstice on a clear day. Size the glazing 1941 and the overhangs so that just the right amount of daylighting is brought into the school during 1942 your summer peak cooling condition. With south-facing glazing, this strategy will result in more 1943 and more daylight to enter the space during other parts of the year, when the sun has a lower 1944 altitude – just what is needed. The glazing area, if south-facing, is typically 25% less than if 1945 north-facing in order to provide the same daylighting. A fully daylit 1,000 ft2 classroom should 1946 have an 8% to 11% monitor fenestration to floor area ratio (FFR), with 65-75% VLT for the 1947 daylighting fenestration. Glazing with a lower light transmission may be used, but the aperture 1948 should be increased to maintain the same effective visible aperture area (fenestration area x 1949 VLT). Where windows are used specifically for daylighting, consider the use of uncoated clear 1950 glass or low-e coated clear glass with a high VLT. A larger daylighting aperture with a lower 1951 VLT has the advantage of providing the same amount of daylight but with less glare and 1952 contrast. The disadvantage is typically the costs associated with all the components of the 1953 daylighting system are higher. 1954

DL-29 Overhang for Roof Monitor (Climate Zones: all) 1955

Assuming the school is in a location that has winter heating requirement, think about placing the 1956 overhang much as would be if designing a passive solar building. Start out by placing the outer 1957 point of the overhang on an angle about 45 degrees from horizontal, above the head of the 1958 window. This will allow most of the solar gain to enter during the winter, even at noon when the 1959 altitude is low. 1960

By moving the overhang in and out, and simulating these different conditions during peak 1961 cooling times (as well as annual simulations), the designer will be able to determine the correct, 1962 optimum location. The overhang should not allow anymore radiation entering the space during 1963 peak cooling times than is necessary to deliver the footcandles necessary. If during peak cooling 1964


time the space has higher footcandle levels than is necessary, this will increase you cooling 1965 loads. 1966

Design the south-facing monitor to capture passive heating in the winter months. This will help 1967 in offsetting the heat not being provided when electric lights are off. Do not over-extend the 1968 overhang. It will hurt the daylighting contribution as well as the passive heating benefit. 1969

DL-30 Use Light Colored Roofing in Front of Monitors (Climate Zones: all) 1970 Specify a light-colored roofing material to reflect additional light into the glazing. A white 1971 single-ply roofing material (aged reflectance of 69%) typically provides the best long-term 1972 reflectance. This compares to black EPDM of 6%, a gray SPDM of 23%, or a light colored rock 1973 ballast of 25%. 1974

When white single-ply roofing (see above) is placed directly in front of the south-facing roof 1975 monitors, the glazing area in the monitors is able to be reduced by up to 20% because of the 1976 additional reflected radiation entering the monitor. 1977

The white color also provides an overall benefit by reflecting solar radiation that would 1978 otherwise be absorbed and re-radiated downward into the conditioned space. Energy savings also 1979 result as a benefit of a lowered cooling load. 1980

DL-31 Use Baffles to Block Direct Beam Radiation and Diffuse Light (Climate Zones: all) 1981 In the roof monitor, light well assemblies, white baffles should hang parallel to the glass and be 1982 spaced to ensure that no direct beam enters the space. The spacing and depth of the baffles 1983 should be determined so that when standing inside the room, looking out, the occupants can not 1984 see the sky. This will ensure that no direct beam light can strike the work plane. Baffles should 1985 have the following characteristics: 1986

• The baffles should be fire-retardant and UV resistant. 1987

• Light-colored translucent baffles not only reflect the sunlight into the space, but also help 1988 eliminate contrast from one side of the baffle to the other. 1989

DL-32 Minimize Contrast at Well-Ceiling Intersection (Climate Zones: all) 1990 At the bottom of the light well, contrast is significantly reduced if there is a transition between 1991 the vertical plane and the horizontal. A 45 degree, angled plane is good but a curved transition is 1992 even better. To achieve this curved effect, many designers are now using fiber-reinforced plaster 1993 curved sections that blend nicely with sheetrock. 1994

DL-33 Address the Monitor Design (Climate Zones: all) 1995 To help reduce conductive gains and losses, the walls and ceiling of the roof monitor should be 1996 well insulated and incorporate appropriate infiltration and moisture barriers. 1997

Make sure that the colors used within the monitor well are very light. White is best. Any use of 1998 darker colors will result in a considerable loss in efficiency. 1999

Also consider acoustic issues. If acoustical ceiling material is used, make sure that the 2000 reflectance as well as the acoustical properties are high. Often manufacturers, in presenting the 2001 reflectance of an acoustical tile will specify the paint color. Remember to account for the 2002 reduced reflectance due to the fissures in the tile. 2003


DL-34 Let the heat stratify (Climate Zones: all) 2004 One of the keys to achieving the desired cooling reductions is to rely on the stratification of heat 2005 within the monitor itself. Do not attempt to remove this heat by placing supply and return grilles 2006 in this area, but instead allow the heat to stratify. This benefit is often overlooked in designing 2007 daylit spaces and comparing one strategy to another. 2008

DL-35 Minimize the depth of the ceiling cavity (Climate Zones: all) 2009 The depth of the well is very important. The deeper the well, the harder it is for the radiation to 2010 reflect down into the space. For example, with a seven foot deep, square sky well that has a 70% 2011 reflectance, the loss in effectiveness due to the well will be 50%. 2012

Classroom Sidelighting plus Toplighting 2013 This daylighting pattern is appropriate for one story buildings or for top floor of multi-story 2014 schools. It combines the sidelighting recommendations of the previous pattern with small interior 2015 skylights or roof monitors to balance daylighting across the space. See DL-20 through DL-27 2016 for recommendations for implementing this type of daylighting strategy. 2017

2018

2019

2020 Figure 5 – Sidelit Enhanced with Toplit Skylights or Roof Monitors 2021

2022 Gym Toplighting 2023 For spaces with high ceilings such as gyms, or for larger spaces such as multipurpose rooms, 2024 cafeterias and commons, a basic daylighting design using toplighting is recommended. 2025 Toplighting has the distinct advantage of providing useful daylight under most conditions, and 2026 allows for just about any orientation of the space. 2027


DL-36 Gym Toplighting Sizing 2028 For those performing daylighting calculations using a lighting program, the optimum daylighting 2029 performance will generally be achieved when the maximum average light level reached under 2030 any condition is no more than about 200 footcandles, and there is never any direct sun 2031 penetration producing individual single point light levels higher than 400 footcandles. This will 2032 produce useful daylight ranging from about 20 footcandles to 200 footcandles, average, from 2033 9AM until 3PM in most climate zones . 2034

DL-37 Gym Toplighting - Glazing Area(Climate Zones: all) 2035 For basic daylighting with good results, there are two recommended approaches. 2036

• Employ a grid of skylights in overcast and cool climates. A horizontal daylighting 2037 fenestration-to-floor ratio (FFR) of about 4-5% is suggested using diffusing or prismatic 2038 skylights with VLT of at least 60%. If possible, skylights should be splayed to reduce 2039 glare. Many smaller skylights are better than a few larger ones; as a rule of thumb, the 2040 maximum dimension of a skylight should be about ¼ the skylight’s height above the 2041 floor. Use Skycalc to determine the optimum size of the skylights. 2042

• Employ a south or north facing roof monitor with clerestory. A north facing clerestory is 2043 relatively simple in all climates, but requires a fairly large glazed area (7%-10%of the 2044 floor area) to produce enough daylight. A south facing clerestory can be smaller (5% to 2045 8% of the floor area) but it must be carefully designed with an overhang to shade direct 2046 summer sunlight and interior baffles to diffuse direct sunlight and prevent glare. Note that 2047 high wall north or south clerestories are not recommended as glare can easily be 2048 produced that affects sports performance. 2049


2050

2051 Figure 6 – A typical 7600 ft2 Gymnasium Floor Plan with 4 Roof Monitors 2052

2053

References 2054 CHPS, 2006. Collaborative for High Performance Schools Best Practices Manual Criteria. 2055 http://www.chps.net/manual/documents/BPM_2006_Edition/CHPS_III_2006.pdf 2056

EPRI Daylight Design: Smart & Simple 1997, available from IESNA at IESNA.org 2057


LBL Daylight and Windows. LBL Tips for Daylighting with Windows available from Lawrence 2058 Berkeley National Laboratories at 2059 http://windows.lbl.gov/daylighting/designguide/designguide.html 2060

Daylighting Design by Benjamin Evans, in time Saver Standards for Architectural Design Data, 2061 McGraw-Hill., 1997 2062

IESNA. 1997. EPRI Daylighting Design: Smart and Simple. New York: Illuminating 2063 Engineering Society of North America. 2064

IESNA. 1996. EPRI Lighting Controls—Patterns for Design. New York: Illuminating 2065 Engineering Society of North America. 2066

NBI. 2003. Advanced Lighting Guidelines. White Salmon, WA: New Buildings Institute. 2067 www.newbuildings.org/lighting.htm. 2068

USGBC. 2005. LEED NC Indoor Environment Quality Credit 6.1 “Controllability of Systems: 2069 Lighting.” Washington, DC: U.S. Green Building Council. 2070

2071

Exterior Lighting 2072 The following recommendations are not included in the Recommendation Tables in Chapter 3 2073 because parking lots and grounds are often beyond the control of the individual school. If 2074 designing for parking lots and grounds, follow recommendations EX1 through EX4. 2075

2076

EX-1 Exterior Lighting Power (Climate Zones: all) 2077 Limit exterior lighting power to 0.15 W/ft2 for parking lot and grounds lighting. Calculate only 2078 for paved areas, excluding grounds that do not require lighting. 2079

Limit exterior decorative façade lighting to 0.2 W/ft2 of illuminated surface. This does not 2080 include lighting of walkways or entry areas of the building that may also light the building itself. 2081 Façade lighting can improve feelings of safety and security. Limit the lighting equipment 2082 mounting locations to the building and do not install floodlights onto nearby parking lot lighting 2083 standards. Use downward-facing lighting to comply with light trespass and light pollution 2084 concerns. 2085

2086

EX-2 Sources (Climate Zones: all) 2087 All general lighting luminaires should utilize pulse-start metal halide, fluorescent, induction, or 2088 compact fluorescent amalgam lamps with electronic ballasts. 2089

Standard high-pressure sodium lamps are not recommended due to their reduced visibility and 2090 poor color-rendering characteristics. 2091

Incandescent lamps are not recommended. 2092

For colder climates, fluorescent and compact fluorescent lamp (CFL) luminaires must be 2093 specified with cold-temperature ballasts. Use CFL amalgam lamps. 2094


2095

EX-3 Parking Lighting (Climate Zones: all) 2096 Parking lot lighting locations should be coordinated with landscape plantings so that tree growth 2097 does not block effective lighting from pole-mounted luminaires. 2098

Parking lot lighting should not be significantly brighter than lighting of the adjacent street. 2099 Follow IESNA RP-33-1999 recommendations for uniformity and illuminance recommendations. 2100

For parking lot and grounds lighting, do not increase luminaire wattage in order to use fewer 2101 lights and poles. Increased contrast makes it harder to see at night beyond the immediate fixture 2102 location. Flood lights and non-cutoff wall-packs should not be used, as they cause hazardous 2103 glare and unwanted light encroachment on neighboring properties. Limit lighting in parking and 2104 drive areas to not more than 360-watt pulse-start metal halide lamps at a maximum 25 ft 2105 mounting height in urban and suburban areas. Use cutoff luminaries that provide all light below 2106 the horizontal plane and help eliminate light trespass. 2107

2108

EX-4 Controls (Climate Zones: all) 2109 Use an astronomical time switch for all exterior lighting. Astronomical time switches are capable 2110 of retaining programming and the time setting during loss of power for a period of at least 10 2111 hours. If a building energy management system is being used to control and monitor mechanical 2112 and electrical energy use, it can also be used to schedule and manage outdoor lighting energy 2113 use. Turn off exterior lighting not designated for security purposes when the building is 2114 unoccupied. 2115

2116

References 2117 IESNA. 1998. IESNA RP-20-1998, Recommended Practices and Design Guidelines. New York: 2118 Illuminating Engineering Society of North America. 2119

IESNA. 1999. IESNA RP-33-99, Recommended Practices and Design Guidelines. New York: 2120 Illuminating Engineering Society of North America. 2121

IESNA. 1994. IESNA DG-5-94, Recommended Practices and Design Guidelines. New York: 2122 Illuminating Engineering Society of North America. 2123

IESNA. 2003. IESNA G-1-03, Recommended Practices and Design Guidelines. New York: 2124 Illuminating Engineering Society of North America. 2125

LRC. 1996. Outdoor Lighting Pattern Book. Troy, NY: Lighting Research Center. 2126

2127

HVAC 2128 While it is understood that there are many types of HVAC systems that could be used in K-2129

12 schools, this Guide assumes that one of the following five system types is to be used: 2130 2131

• HV1: Single-zone, packaged units (or split DX systems) with indirect gas-fired heaters, 2132 electric resistance heat, or heat pump 2133

• HV2: Water-source (or ground-source) heat pumps with a dedicated outdoor-air ventilation 2134 system 2135


• HV3: Fan-coils with a water chiller and a hot water boiler or electric resistance heat and a 2136 dedicated outdoor-air ventilation system 2137

• HV4: Multiple-zone, packaged VAV rooftop units with a hot water coil, indirect gas furnace, 2138 or electric resistance for preheat and a hot water coil or electric resistance for reheat in the 2139 VAV terminals. 2140

• HV5: Multiple-zone, VAV air handlers with a water chiller and a hot water coil, indirect gas 2141 furnace, or electric resistance for preheat and a hot water coil or electric resistance for reheat 2142 in the VAV terminals. 2143

2144 This Guide does not cover purchased chilled water for cooling, or solar, steam, or purchased 2145

steam for heating. These and other systems are alternative means that may be used to achieve the 2146 energy savings target of this Guide. 2147

2148

Good Design Practices 2149

HV1. Single-zone, packaged units (or split DX systems) (Climate Zones: all) 2150 In this system, a separate packaged DX unit (or split DX system) is used for each thermal 2151

zone. This type of equipment is available in pre-established increments of capacity. The 2152 components are factory-designed and -assembled and include outdoor- and return-air dampers, 2153 fans, filters, heating source, cooling coil, compressor, controls, and an air-cooled condenser. The 2154 heating source is provided by either an indirect-fired gas burner, electric resistance heat, or by 2155 reversing the refrigeration circuit to operate the unit as a heat pump. Gas heaters are part of the 2156 factory-assembled unit. Electric resistance heaters can be part of the factory-assembled unit or 2157 can be installed in the duct system. Heat pump units may also use an auxiliary heat source 2158 (typically electric resistance heat) during the defrost cycle. 2159

The components can be assembled as a single package (such as a rooftop unit) or a split 2160 system that separates the evaporator and condenser/compressor sections. Single packaged units 2161 are typically mounted on the roof or at grade level outdoors. Split systems generally have the 2162 indoor unit (including fan, filters and coils) located indoors or in an unconditioned space and the 2163 condensing unit located outdoors on the roof or at grade level. On smaller systems, the fan is 2164 commonly incorporated in an indoor furnace section. The indoor unit may also be located 2165 outdoors; if so, it should be mounted on the roof to avoid installing ductwork outside the 2166 building envelope. The equipment should be located to meet the acoustical goals of the space, 2167 while minimizing fan power, ducting, and wiring. 2168

Performance characteristics vary among manufacturers, and the selected equipment should 2169 match the calculated heating and cooling loads (sensible and latent), also taking into account the 2170 importance of providing adequate dehumidification under part-load conditions (see HV7). The 2171 equipment should be listed as being in conformance with electrical and safety standards with its 2172 performance ratings certified by a nationally recognized certification program. 2173

The cooling equipment, heating equipment, and fans should meet or exceed the efficiency 2174 levels listed in the climate-specific tables in Chapter 3. The cooling equipment should also meet 2175 or exceed the part-load efficiency level, where shown. 2176 2177 HV2. Water-source (or ground-source) heat pumps (Climate Zones: all) 2178

In this system, a separate water-source heat pump (WSHP) is used for each thermal zone. 2179 This type of equipment is available in pre-established increments of capacity. The components 2180 are factory-designed and -assembled and include a filter, fan, refrigerant-to-air heat exchanger, 2181


compressor, refrigerant-to-water heat exchanger, and controls. The refrigeration cycle is 2182 reversible, allowing the same components to provide cooling or heating. 2183

Individual water-source heat pumps are typically mounted in the ceiling plenum over the 2184 corridor (or some other non-critical space) or in a closet next to the occupied space. The 2185 equipment should be located to meet the acoustical goals of the space, while minimizing fan 2186 power, ducting, and wiring. 2187

In a traditional WSHP system, all the heat pumps are connected to a common water loop. A 2188 cooling tower and a hot-water boiler are also installed in this loop to maintain the temperature of 2189 the water within a desired range. 2190

A variation of this system takes advantage of the relatively-constant temperature of the earth, 2191 and uses the ground instead of the cooling tower and boiler. Ground-source heat-pump systems 2192 (see AS-3) do not actually get rid of heat, they store it in the ground for use at a different time. 2193 During the summer, the heat pumps extract heat from the building and transfer it to the ground. 2194 When the building requires heating, this stored heat can be recaptured from the ground. In a 2195 perfectly balanced system, the amount of heat stored over a given period of time would equal the 2196 amount of heat retrieved. This offers the potential to reduce (or eliminate) the energy used by a 2197 cooling tower and/or boiler, but installation costs may be higher due to the geothermal heat 2198 exchanger. 2199

Outdoor air is conditioned and delivered by a separate, dedicated ventilation system. This 2200 may involve either ducting the outdoor air directly to each heat pump, delivering it in close 2201 proximity to the heat pump intakes, or ducting it directly to the occupied spaces. Depending on 2202 the climate, the dedicated outdoor-air unit may include components to cool, heat, dehumidify, or 2203 humidify the outdoor air (see HV11). 2204

The cooling equipment, heating equipment, and fans should meet or exceed the efficiency 2205 levels listed in the climate-specific tables in Chapter 3. The cooling equipment should also meet 2206 or exceed the part-load efficiency level, where shown. 2207

2208 HV3. Fan-coils (Climate Zones: all) 2209

In this system, a separate fan-coil unit is used for each thermal zone. The components are 2210 factory-designed and -assembled and include filters, a fan, heating and cooling coils, controls, 2211 and possibly outdoor- and return-air dampers. 2212

Fan-coils are typically installed within each conditioned space, in the ceiling plenum above 2213 the corridor (or some other non-critical space), or in a closet adjacent to the space. However, the 2214 equipment should be located to meet the acoustical goals of the space, while minimizing fan 2215 power, ducting, and wiring. 2216

All the fan-coils are connected to a common water distribution system. Cooling is provided 2217 by centralized water chiller. Heating is provided by either a centralized boiler or by electric 2218 resistance heat located inside each fan-coil. 2219

Outdoor air is conditioned and delivered by a separate, dedicated ventilation system. This 2220 may involve either ducting the outdoor air directly to each fan-coil or ducting it directly to the 2221 occupied spaces. Depending on the climate, the dedicated outdoor-air unit may include 2222 components to cool, heat, dehumidify, or humidify the outdoor air (see HV11). 2223


2227


HV4. Multiple-zone, packaged VAV rooftop units (Climate Zones: all) 2228 In this system, a packaged rooftop unit serves several individually-controlled zones. Each 2229

thermal zone has a VAV terminal unit that is controlled to maintain temperature in that zone. 2230 The components of the rooftop unit are factory-designed and -assembled and include outdoor- 2231 and return-air dampers, filters, fans, cooling coils, heating source, compressors, condenser, and 2232 controls. The components of the VAV terminal units are factory-designed and -assembled and 2233 include an airflow-modulation device, controls, and possibly a heating coil, fan, or filter. 2234

VAV terminal units are typically installed in the ceiling plenum above the occupied space or 2235 adjacent corridor. The equipment should be located to meet the acoustical goals of the space, 2236 while minimizing fan power, ducting, and wiring. 2237

All the VAV terminal units are connected to a common air distribution system. Cooling is 2238 provided by the centralized rooftop unit. Heating is typically provided by either an indirect-fired 2239 gas burner or hot water coil inside the rooftop unit, individual heating coils (hot water or electric 2240 resistance) located inside the VAV terminal units, or perimeter radiant heat located within the 2241 occupied space. 2242


For VAV systems, the minimum supply airflow to a zone must comply with local code and 2246 the current version of ASHRAE Standard 90.1. 2247

2248 HV5. Multiple-zone, VAV air handlers (Climate Zones: all) 2249

In this system, a central air handler serves several individually-controlled zones. Each 2250 thermal zone has a VAV terminal unit that is controlled to maintain temperature in that zone. 2251 The components of the VAV air handler include outdoor- and return-air dampers, filters, fans, 2252 cooling coil, heating source, and controls. The components of the VAV terminal units are 2253 factory-designed and -assembled and include an airflow-modulation device, controls, and 2254 possibly a heating coil, fan, or filter. 2255

VAV terminal units are typically installed in the ceiling plenum above the occupied space or 2256 adjacent corridor. The equipment should be located to meet the acoustical goals of the space, 2257 while minimizing fan power, ducting, and wiring. 2258

All the VAV terminal units are connected to a common air distribution system. All the air 2259 handlers are connected to a common water distribution system. Cooling is provided by the 2260 centralized water chiller. Heating is typically provided by either an indirect-fired gas burner, hot 2261 water coil, or electric resistance heat located inside the VAV air handler, individual heating coils 2262 (hot water or electric resistance) located inside the VAV terminal units, or perimeter radiant heat 2263 located within the occupied space. 2264


For VAV systems, the minimum supply airflow to a zone must comply with local code and 2268 the current version of ASHRAE Standard 90.1. 2269

2270 HV6. Cooling and Heating Load Calculations (Climate Zones: all) 2271

Design cooling and heating loads must be calculated in accordance with generally-accepted 2272 engineering standards and handbooks, such as the ASHRAE Handbook—Fundamentals . Safety 2273 factors should be applied cautiously to prevent oversizing of equipment. Oversized cooling 2274


equipment has limited ability to reduce capacity at part-load conditions, thus causing short-2275 cycling of compressors which leads to limited ability of the system to dehumidify (see HV7). 2276

Cooling and heating loads of outdoor (ventilation) air must be included in the load 2277 calculations, as well as accurate lighting and plug loads. Separate load calculations must be 2278 performed on each thermal zone type, as well as on each occupancy/activity zone type. 2279

Accurate sizing of equipment leads to lower equipment costs, lower utility costs, better 2280 dehumidification performance, and more comfortable conditions. 2281 2282

HV7. Part-Load Dehumidification (Climate Zones: all) 2283 Most basic, constant-volume systems (small packaged rooftop units, DX split systems, fan-2284

coils, water-source heat pumps, etc.) supply a zone with a constant amount of air regardless of 2285 the cooling load. The system must deliver warmer air under part-load conditions to avoid 2286 overcooling the space. 2287

In a typical chilled-water application, a modulating valve reduces system capacity by 2288 throttling the water flow rate through the cooling coil. The warmer coil surface that results 2289 provides less sensible cooling (raising the supply-air dry-bulb temperature)—but it also removes 2290 less moisture from the passing air stream (raising the supply-air dew point). 2291

In a typical direct-expansion (DX) application, the compressor cycles off regularly to avoid 2292 overcooling. As the compressor operates for a smaller percentage of the hour, dehumidification 2293 capacity decreases significantly. The compressor doesn’t run long enough for the accumulated 2294 condensate to fall into the drain pan, and it stays off for longer periods of time, allowing the 2295 remaining moisture on the coil surface to re-evaporate while the fan continues to run. 2296

Briefly stated, a basic constant-volume system matches sensible capacity to the sensible load; 2297 dehumidification capacity is coincidental. As the load diminishes, the system delivers ever 2298 warmer supply air. Some dehumidification may occur… but only if the sensible load is high 2299 enough. As a result, the space relative humidity will tend to increase under part-load conditions. 2300 Therefore, select systems that minimize the number of hours that the space relative humidity 2301 remains above 60%. 2302

For single-zone, packaged units or split DX systems (see HV1): Packaged rooftop units 2303 (or split DX systems) could be equipped with hot gas reheat for direct control of space humidity. 2304 Alternatively, a dedicated outdoor-air system (see HV11) could be added and designed to 2305 dehumidify the outdoor air so that it is dry enough (low enough dew point) to offset the latent 2306 loads in the spaces. This helps avoid high indoor humidity levels without the need for additional 2307 dehumidification enhancements in the local DX units. 2308

For water-source (or ground-source) heat pumps (see HV2): The dedicated outdoor-air 2309 system (see HV11) should be designed to dehumidify the outdoor air so that it is dry enough 2310 (low enough dew point) to offset the latent loads in the spaces. This helps avoid high indoor 2311 humidity levels without the need for additional dehumidification enhancements in the WSHP 2312 units. Alternatively, some WSHPs could be equipped with hot gas reheat for direct control of 2313 space humidity. 2314

For fan-coil units (see HV3): The dedicated outdoor-air system (see HV11) should be 2315 designed to dehumidify the outdoor air so that it is dry enough (low enough dew point) to offset 2316 the latent loads in the spaces. This helps avoid high indoor humidity levels without the need for 2317 additional dehumidification enhancements in the fan-coil units. Alternatively, fan-coils could be 2318 equipped with multiple-speed fans for improved part-load dehumidification or a reheat coil for 2319 direct control of space humidity. 2320

For multiple-zone, packaged VAV rooftop units (see HV4): VAV systems typically 2321 dehumidify effectively over a wide range of indoor loads, as long as the VAV rooftop unit 2322


continues to provide cool, dry air at part-load conditions. One caveat: Use caution when resetting 2323 the supply-air-temperature (SAT) during the cooling season. Warmer supply air means less 2324 dehumidification at the coil and higher humidity in the space. If SAT reset is used, include one 2325 or more zone humidity sensors to disable reset if the relative humidity within the space exceeds 2326 60%. 2327

For multiple-zone, VAV air handlers (see HV5): VAV systems typically dehumidify 2328 effectively over a wide range of indoor loads, as long as the VAV rooftop unit continues to 2329 provide cool, dry air at part-load conditions. One caveat: Use caution when resetting the supply-2330 air temperature (SAT) or chilled-water (CHW) temperature during the cooling season. Warmer 2331 supply air (or water) means less dehumidification at the coil and higher humidity in the space. If 2332 SAT or CHW reset is used in a humid climate, include one or more zone humidity sensors to 2333 disable reset if the relative humidity within the space exceeds 60%. 2334

2335 HV8. Exhaust Air Energy Recovery (Climate Zones: all) 2336

Exhaust-air energy recovery can provide an energy-efficient means of reducing the latent and 2337 sensible outdoor air cooling loads during peak summer conditions. It can also reduce the outdoor 2338 air heating load in mixed and cold climates. Systems using energy recovery need to re-size the 2339 HVAC system (see ASHRAE Handbook – HVAC Systems and Equipment). 2340

Sensible-energy recovery devices transfer only sensible heat. Common examples include coil 2341 loops, fixed-plate heat exchangers, heat pipes, and sensible-energy rotary heat exchangers 2342 (sensible-energy wheels). Total-energy recovery systems not only transfer sensible heat, but 2343 moisture (or latent heat) as well—that is, energy stored in water vapor in the air stream. Common 2344 examples include total-energy rotary heat exchangers (also known as total-energy wheels or 2345 enthalpy wheels) and fixed-membrane heat exchangers (See Figure below). 2346

2347

2348 Figure: Examples of exhaust-air energy recovery devices. 2349

2350 An exhaust-air energy recovery device can be packaged in a separate energy recovery 2351

ventilator (ERV) that conditions the outdoor air before it enters the air-conditioning unit, or the 2352 device can be integral to the air-conditioning unit itself. 2353


For maximum benefit, the system should provide as close to balanced outdoor and exhaust 2354 airflows as is practical, taking into account the need for building pressurization and any exhaust 2355 that cannot be ducted back to the energy recovery device. 2356

Exhaust for ERVs may be taken from spaces requiring exhaust (using a central exhaust duct 2357 system for each unit) or directly from the return airstream (as with a unitary accessory or 2358 integrated unit). (See also HV13 – Exhaust Air Systems.) 2359

Where an airside economizer is used along with an ERV, add bypass dampers (or a separate 2360 outdoor-air path) to reduce the airside pressure drop during economizer mode. In addition, the 2361 energy recovery device should be turned off during economizer mode, to avoid adding heat to 2362 the outdoor airstream. Where energy recovery is used without an airside economizer, the energy 2363 recovery device should be controlled to prevent the transfer of unwanted heat to the outdoor 2364 airstream during mild outdoor conditions. 2365

In cold climates, follow the manufacturer’s recommendations for frost prevention. 2366 2367

HV9. Cooling and Heating Equipment Efficiencies (Climate Zones: all) 2368 The cooling and heating equipment should meet or exceed the efficiency levels listed in the 2369

climate-specific tables in Chapter 3. The cooling equipment should also meet or exceed the 2370 part-load efficiency level where shown. 2371

Heating equipment should meet or exceed the efficiency levels listed in the climate-specific 2372 tables in Chapter 3. 2373

There are many factors in making a decision whether to use gas or electricity, such as 2374 availability of service, operator familiarity, and so on. Efficiency recommendations for both 2375 types of equipment are provided to allow for choice by the user. 2376 2377

HV10. Ventilation Air (Climate Zones: all) 2378 The zone-level outdoor airflows, and the system-level intake airflow, should be determined 2379

based on the current version of ASHRAE Standard 62.1, but should not be less than the values 2380 required by local code unless approved by the authority having jurisdiction. The number of 2381 people used in computing the breathing zone ventilation rates should be based on either known 2382 occupancy, local code, or the default values listed in ASHRAE 62.1. 2383

Buildings with multiple-zone, recirculating ventilation systems (MZS) can be designed to 2384 account for recirculated outdoor air, as well as system population diversity (D), using the 2385 equations found in ASHRAE 62.1-2007 (Section 6.2.5). In effect, the MZS design approach 2386 allows ventilation air to be calculated on the basis of how many people are in the building 2387 (system population at design) rather than the sum of how many people are in each space (sum-2388 of-peak zone population at design). This can reduce the energy required to condition ventilation 2389 air in K-12 schools. Refer to the Standard 62.1 User’s Manual for specific guidance. 2390

For single-zone, packaged units or split DX systems (see HV1): Each air-conditioning or 2391 heat pump system should have an outdoor air connection through which outdoor air is introduced 2392 and mixes with the return air. The outdoor air can be mixed with the return air either in the 2393 ductwork prior to the air-conditioning or heat pump unit or at the unit’s mixing plenum. In either 2394 case, the damper and duct/plenum should be arranged to promote mixing and minimize 2395 stratification. Alternatively, a dedicated outdoor-air system (see HV11) could be used to deliver 2396 outdoor air directly to each zone or to each individual packaged unit (or indoor unit in a split DX 2397 system). 2398

For water-source (or ground-source) heat pumps (see HV2): The dedicated outdoor-air 2399 system (see HV11) should deliver the conditioned outdoor air directly to each zone, to the intake 2400


of each individual heat pump (where it mixes with return air, either in the ductwork prior to the 2401 heat pump or in a mixing plenum attached to the heat pump), or to the supply-side of each 2402 WSHP (where it mixes with supply air from the heat pump before being delivered to the zone). 2403

For fan-coil units (see HV3): The dedicated outdoor-air system (see HV11) should deliver 2404 the conditioned outdoor air directly to each zone, to the intake of each individual fan-coil (where 2405 it mixes with return air, either in the ductwork prior to the fan-coil or in a mixing plenum 2406 attached to the fan-coil), or to the supply-side of each fan-coil (where it mixes with supply air 2407 from the fan-coil before being delivered to the zone). 2408

For multiple-zone, packaged VAV rooftop units (see HV4): Each rooftop unit should have 2409 an outdoor air intake through which outdoor air is introduced and mixes with the return air, prior 2410 to being delivered to the zones. Alternatively, a dedicated outdoor-air system (see HV11) could 2411 be used to deliver outdoor air directly to each zone, to individual dual-duct VAV terminals that 2412 serve each zone, or to the outdoor-air intake of one or more packaged VAV rooftop units. 2413

For multiple-zone, VAV air handlers (see HV5): Each VAV air handler should have an 2414 outdoor air intake through which outdoor air is introduced and mixes with the return air, prior to 2415 being delivered to the zones. Alternatively, a dedicated outdoor-air system (see HV11) could be 2416 used to deliver outdoor air directly to each zone, to individual dual-duct VAV terminals that 2417 serve each zone, or to the outdoor-air intake of one or more VAV air handlers. 2418

2419 HV11. Dedicated Outdoor-Air Systems (Climate Zones: all) 2420

Dedicated outdoor air systems (DOAS) can reduce energy use by decoupling the 2421 dehumidification of outdoor ventilation air from sensible cooling and heating in the zone. The 2422 ventilation air is conditioned by a separate dedicated OA unit that is designed to dehumidify 2423 ventilation air, and deliver the air dry enough to offset space latent loads (Mumma & Shank 2424 2001). Terminal HVAC equipment, which is located in or near each space, heats or cools 2425 recirculated indoor air to maintain space temperature. Terminal equipment may include fan-coil 2426 units, water-source heat pumps, zone-level air handlers, radiant cooling panels, fan-powered 2427 VAV terminals, or a dual-fan, dual-duct arrangement. Dedicated OA systems can also be used in 2428 conjunction with multiple-zone recirculating systems, in which the ventilation system is sized 2429 based on ASHRAE Standard 62.1-2007 (Section 6.2.5). 2430

Consider delivering the conditioned outdoor air cold (not reheated to neutral) whenever 2431 possible, and use recovered energy to reheat only when needed. Providing cold (rather than 2432 neutral) air from the dedicated OA unit offsets a portion of the space sensible cooling loads, 2433 allowing the terminal HVAC equipment to be downsized and use less energy. In addition, 2434 implementing system-level control strategies and exhaust-air energy recovery (se HV8) can help 2435 minimize energy use. 2436

While there are many possible DOAS configurations, the figure below includes a few typical 2437 configurations. The salient energy-saving feature of dedicated OA systems is the separation of 2438 ventilation air conditioning from zone air conditioning. 2439

2440


2441 Figure: Examples of dedicated outdoor-air system configurations. 2442

2443

HV12. Economizer (Climate Zones: 3, 4, 5, 6, 7, 8) 2444 Economizers, when recommended, help save energy by providing free cooling when ambient 2445

conditions are suitable to meet all or part of the cooling load. In humid climates, consider using 2446 enthalpy-based controls (versus dry-bulb temperature controls) to help ensure that unwanted 2447 moisture is not introduced into the space. Economizers are not recommended in climate zone 1. 2448 There may be some applicability in dry climate areas in climate zone 2. 2449

Non-dedicated outdoor-air systems should be capable of modulating the outdoor air, return 2450 air, and relief air dampers to provide up to 100% of the design supply air quantity as outdoor air 2451 for cooling. (See HV11 for discussion of dedicated outdoor-air systems.) Systems should use a 2452 motorized outdoor air damper instead of a gravity damper to prevent outdoor air from entering 2453 during the unoccupied periods when the unit may recirculate air to maintain setback or setup 2454 temperatures. The motorized outdoor air damper for all climate zones should be closed during 2455 the entire unoccupied period, except when it may open in conjunction with an economizer cycle. 2456

Periodic maintenance is important with economizers, as dysfunctional economizers can cause 2457 substantial excess energy consumption due to malfunctioning dampers and/or sensors. See HV29 2458 for more information on maintenance of outdoor air dampers. 2459 2460


HV13. Demand-Controlled Ventilation (Climate Zones: all) 2461 Demand-controlled ventilation (DCV) can reduce the energy required to condition outdoor 2462

air for ventilation. However, to maintain acceptable indoor air quality (IAQ), the setpoints 2463 (limits) and control sequence must comply with ASHRAE 62.1. Refer to the Standard 62.1 2464 User’s Manual for specific guidance. 2465

DCV varies the amount of outdoor air in response to the need in a zone. The amount of 2466 outdoor air could be controlled by either 1) a time-of-day schedule in the building automation 2467 system, 2) an occupancy sensor that indicates when a zone is occupied versus unoccupied, or 3) a 2468 carbon dioxide (CO2) sensor, as a proxy for ventilation airflow per person, that measures the 2469 change in carbon dioxide levels in a zone relative to the levels in the outdoor air. A controller 2470 will operate the outdoor air, return air, and relief air dampers to maintain proper ventilation. 2471

DCV should be used in single-zone systems serving areas that are densely-occupied, with 2472 highly-variable occupancy patterns during the occupied periods—such as gymnasiums, 2473 auditoriums, multipurpose spaces, cafeterias, and possibly some classrooms. Multiple-zone, 2474 recirculating systems (such as VAV systems) require special attention to assure adequate outdoor 2475 air is supplied to all zones under varying loads. Employing DCV in a dedicated outdoor-air 2476 ventilation system requires to addition of an automatic damper and sensor for each DCV zone. 2477

CO2 sensors should be certified by the manufacturer to have an error of 75 ppm or less and 2478 be factory calibrated. Inaccurate CO2 sensors can cause excessive energy consumption or poor 2479 indoor air quality, so these sensors need to be calibrated as recommended by the manufacturer. 2480

Finally, when DCV is used, the system controls should also control building pressure. If the 2481 amount of air exhausted remains constant while the intake airflow decreases, the building may be 2482 under a negative pressure relative to outdoors. When air is exhausted directly from the zone (art 2483 or vocational classrooms, science laboratories, kitchens, locker rooms, or even a classroom with 2484 a restroom connected to it), the DCV control strategy must avoid reducing intake airflow below 2485 the amount required to replace the air being exhausted. 2486 2487

HV14. Exhaust Air Systems (Climate Zones: all) 2488 Zone exhaust airflows (for restrooms, janitorial closets, science laboratories, kitchen, art and 2489

vocational classrooms, locker rooms, etc.) should be determined based on the current version of 2490 ASHRAE Standard 62.1, but should not be less than the values required by local code unless 2491 approved by the authority having jurisdiction. 2492

Central exhaust systems for restrooms, janitorial closets, and locker rooms should be 2493 interlocked to operate with the air-conditioning system, except during unoccupied periods. These 2494 exhaust systems should have a motorized damper that opens and closes with the operation of the 2495 fan. The damper should be located as close as possible to the duct penetration of the building 2496 envelope to minimize conductive heat transfer through the duct wall and avoid having to insulate 2497 the duct. During unoccupied periods, the damper should remain closed and the exhaust fan 2498 turned off, even if the air-conditioning system is operating to maintain setback or setup 2499 temperatures. Consider designing exhaust ductwork to facilitate recovery of energy (see HV8) 2500 from Class 1 and Class 2 (e.g. restrooms) exhaust air, per the requirements of ASHRAE Standard 2501 62.1-2007. 2502

Kitchens will generally have separate exhaust and make-up air systems according the usage 2503 of the kitchen and to the equipment manufacturers’ suggestions. If showers are provided in 2504 locker rooms, exhaust must be increased during usage and will generally require separate air 2505 intake (intake hood or make-up air unit). Science laboratories should have exhaust systems if 2506 noxious chemicals or preservatives are used. Make-up air will be necessary to prevent room 2507 pressure from becoming negative with respect to the outside. 2508


2509

HV15. Ductwork Design and Construction (Climate Zones: all) 2510 Low-energy ductwork design involves short, direct. and low pressure drop runs. The number 2511

of fittings should be minimized and should be designed with the least amount of turbulence 2512 produced. (In general, the cost of a duct fitting is approximately the same as 12 ft. of straight 2513 duct, which is the same size as the upstream segment.) Unwanted noise in the ductwork is a 2514 direct result of air turbulence. Round duct is preferred over rectangular duct. However, due to 2515 possible space (height) restrictions, flat oval ductwork may be necessary to achieve the low 2516 turbulence qualities of round ductwork. 2517

Air should be ducted through low-pressure ductwork with a system pressure classification of 2518 less than 2 in. Rigid ductwork is necessary to maintain low pressure loss and reduce fan energy. 2519 Supply air should be ducted to diffusers in each individual space. 2520

In general, the following sizing criteria should be used for duct system components: 2521

1) Diffusers and registers, including balancing dampers, should be sized with a static 2522 pressure drop no greater than 0.08 in. H2O. 2523

2) Supply ductwork should be sized with a pressure drop no greater than 0.08 in. H2O per 2524 100 linear feet of duct run. Return ductwork should be sized with a pressure drop no 2525 greater than 0.04 in H2O and exhaust ductwork with a pressure drop no greater than 0.05 2526 in H2O. 2527

3) Flexible ductwork should be of the insulated type and should be: 2528

• limited to connections between duct branch and diffusers, 2529 • limited to connections between duct branch and variable air volume (VAV) terminal 2530

units, 2531 • limited to 5 ft (fully stretched length) or less, 2532 • installed without any kinks, 2533 • installed with a durable elbow support when used as an elbow, 2534 • installed with no more that 15% compression from fully stretched length, 2535

Hanging straps, if used, need to use a saddle to avoid crimping the inside cross-sectional 2536 area. For ducts with 12 in. or less diameter use a 3 in. saddle; for larger than 12 in. use a 5 2537 in. saddle. 2538

2539 Long-radius elbows and 45° lateral take-offs should be used wherever possible. The angle of 2540

a reduction transition should be no more that 45° (if one side used)or 22.5° (if two sides are 2541 used). The angle of expansion transitions should be no more than 15° (laminar air expands 2542 approximately 7°). 2543

Air should be returned or exhausted through appropriately-placed grilles. Good practice is to 2544 direct supply-air diffusers toward the exterior envelope and to located return-air grilles near the 2545 interior walls, close to the door. 2546

Returning air to a central location (as in a multiple-zone, recirculating system) is necessary to 2547 reap the benefits of reducing ventilation air due to system population diversity (see HV10). 2548 Fully-ducted return systems are expensive and must be connected to a single air handler (or the 2549 return ducts must be interconnected) in order to function as a multiple-zone, recirculating 2550 system. Open plenum return systems are less expensive, but the plenum must be carefully 2551 designed and constructed to prevent infiltration of humid air from outdoors (Harriman 2001). 2552


The ceiling plenum must also be well sealed to minimize air infiltration. Infiltration can be 2553 reduced by using a relief fan to maintain plenum pressure at about 0.05 in. H2O (see HV26), and 2554 lowering indoor humidity levels can reduce the risk of condensation (see HV7 and HV11). In 2555 addition, exhaust duct systems should be properly sealed to prevent infiltration. 2556

Caution: Using plenum return systems in school building that have sloped roofs and eaves in 2557 cold climates with snow requires special attention to insulation. Insulation between the plenum 2558 and the roof must be continuous and well sealed. Leakage of warm air from the plenum to the 2559 roof can melt snow and form ice dams on the eaves. This can result in seepage of water into the 2560 structure. 2561

Ductwork should not be installed outside the building envelope. Ductwork connected to 2562 rooftop units should enter or leave the unit through an insulated roof curb around the perimeter 2563 of the unit’s footprint. Flexible duct connectors should be used to prevent sound transmission 2564 and vibration. 2565

Duct board should be airtight (duct seal level B, from ASHRAE 90.1) and should be taped 2566 and sealed with products that maintain adhesion. Duct static pressures should be designed, and 2567 equipment and diffuser selections should be selected, not to exceed noise criteria for the space 2568 (see HV28 for additional information on noise control). 2569 2570

HV16. Duct Insulation (Climate Zones: all) 2571 All supply air ductwork should be insulated. All return air ductwork located above the ceiling 2572

and below the roof should be insulated. All outdoor air ductwork should be insulated. All 2573 exhaust and relief air ductwork between the motor-operated damper and penetration of the 2574 building exterior should be insulated. 2575

Duct liner should be non-fibrous and non-absorptive, as well as comply with NFPA 90A 2576 and 90B. 2577

Exception: In conditioned spaces without a finished ceiling, only the supply air main ducts 2578 and major branches should be insulated. Individual branches and run-outs to diffusers in the 2579 space being served do not need to be insulated, except where it may be necessary to prevent 2580 condensation. 2581 2582

HV17. Duct Sealing and Leakage Testing (Climate Zones: all) 2583 The ductwork should be sealed for Seal Class B from ASHRAE 90.1 and leak-tested at the 2584

rated pressure. The leakage should not exceed the allowable cfm/100 ft2 of duct area for the 2585 seal and leakage class of the system’s air quantity apportioned to each section tested. See 2586 HV21 for guidance on ensuring the air system performance. 2587 2588

HV18. Fan Motor Efficiencies (Climate Zones: all) 2589 Motors for fans 1 hp or greater should meet National Electrical Manufacturers Association 2590

(NEMA) premium efficiency motor guidelines when available. Fan systems should meet or 2591 exceed the efficiency levels listed in the climate-specific tables in Chapter 3. 2592 2593

HV19. Thermal Zoning (Climate Zones: all) 2594 K-12 school buildings should be divided into thermal zones based on building size, 2595

orientation, space layout and function, and after-hours usage requirements. 2596


Zoning can also be accomplished using multiple HVAC units or a central system that provides 2597 independent control for multiple zones. The temperature sensor for each zone should be installed in 2598 a location representative of that entire zone. 2599

When using a multiple-zone system (such as a VAV system) or a dedicated outdoor-air system, 2600 avoid using a single air handler (or rooftop unit) to serve zones that have significantly different 2601 occupancy patterns. Using multiple air handlers (or rooftop units) allows air handlers serving 2602 unused areas of the building to be shut off, even when another area of the building is still in use. 2603 An alternate approach is to use the building automation system to define separate operating 2604 schedules for these different areas of the building, thus shutting off airflow to the unused areas 2605 while continuing to provide comfort and ventilation to areas of the building that are still in use. 2606 2607

HV20. System-Level Control Strategies (Climate Zones: all) 2608 Control strategies can be designed to help reduce energy. Having a setback temperature for 2609

unoccupied periods during the heating season, or a setup temperature during the cooling season, 2610 can help to save energy by avoiding the need to operate heating, cooling, and ventilation 2611 equipment. Use of programmable thermostats allows each zone to vary the temperature setpoint 2612 based on time of day and day of the week. But they also allow occupants to override these 2613 setpoints or ignore the schedule altogether (by using the "hold" feature of the thermostat), thus 2614 thwarting any potential for energy savings. A more sustainable approach is to equip each zone 2615 with a zone temperature sensor and then use a system-level controller that coordinates the 2616 operation of all components of the system. This system-level controller contains time-of-day 2617 schedules that define when different areas of the building are expected to be unoccupied. 2618 During these times, the system is shut off and the temperature is allowed to drift away from the 2619 occupied setpoint. 2620

A pre-occupancy ventilation period can help purge the building of contaminants that build 2621 up overnight from the off-gassing of products and packaging materials. When it is cool at night, 2622 it can also help pre-cool the building. In hot, humid climates, however, care should be taken to 2623 avoid excessive indoor humidity levels during unoccupied periods. 2624

Optimal start uses a system-level controller to determine the length of time required to bring 2625 each zone from the current temperature to the occupied setpoint temperature. Then, the 2626 controller waits as long as possible before starting the system, so that the temperature in each 2627 zone reaches occupied setpoint just in time for occupancy. This strategy reduces the number of 2628 hours that the system needs to operate, and saves energy by avoiding the need to maintain the 2629 indoor temperature at occupied setpoint even though the building is unoccupied. 2630

Chilled water reset can reduce chiller energy use at part-load conditions. But, it should only 2631 be used in a constant-flow (not variable-flow) pumping system, and it should be disabled when 2632 it is humid outdoors or if space humidity levels rise about 60% RH. 2633

In a VAV system, supply-air-temperature (SAT) reset should be implemented so that it 2634 minimizes overall system energy use. This requires considering the trade-off between 2635 compressor, reheat, and fan energy, as well as the impact on space humidity levels. If SAT reset 2636 is used in a humid climate, include one or more zone humidity sensors to disable reset if the 2637 relative humidity within the space exceeds 60%. 2638

2639 HV21. Testing, Adjusting, and Balancing (Climate Zones: all) 2640

After the system has been installed, cleaned, and placed in operation, the system should be 2641 tested, adjusted, and balanced (TAB) in accordance with ASHRAE Standard 111 or 2642 SMACNA’s Testing, Adjusting and Balancing manual. 2643


This procedure will help to ensure that the correctly-sized diffusers, registers, and grilles 2644 have been installed, that each space receives the required airflow, and that the fans meet the 2645 intended performance. The TAB subcontractor should certify that the instruments used in the 2646 measurement have been calibrated within 12 months prior to use. A written report should be 2647 submitted for inclusion in the O&M manuals. 2648 2649

HV22. Commissioning (Climate Zones: all) 2650 After the system has been installed, cleaned, and placed in operation, the system should be 2651

commissioned to ensure that the equipment meets the intended performance and that the controls 2652 operate as intended. See Appendix C, Commissioning and Quality Assurance, for more 2653 information on commissioning. 2654 2655

HV23. Filters (Climate Zones: all) 2656 Particulate air filters are typically included as part of the factory-assembled HVAC equipment 2657

and should be at least MERV 8, based on ASHRAE Standard 52.2. Use a filter differential 2658 pressure gauge to monitor the pressure drop across the filters and send an alarm if the 2659 predetermined pressure drop is exceeded. Filters should be replaced when the pressure drop 2660 exceeds the filter manufacturer’s recommendations for replacement, or when visual inspection 2661 indicates the need for replacement. The gauge should be checked and the filter should be visually 2662 inspected at least once a year. 2663

Upon completion of construction, all filters should be replaced prior to building occupancy. 2664 2665

HV24. Chilled-Water System (Climate Zones: all) 2666 Chilled water systems can be an efficient way to move energy around the building, and with 2667

the load profile of many schools, they can be a great way to combine a thermal storage system as 2668 well (see AS-4). Chillers should be primary/secondary design, with constant flow through the 2669 chillers, and variable flow through the building. This reduces pipe size outside of the mechanical 2670 room, provides significant pump savings, and with constant flow through the chillers ensures 2671 minimum water flow through the chiller. Consider variable primary flow for water-cooled 2672 applications with significant water pressure drops (>100 ft of H2O), or large applications (>1000 2673 tons). 2674

Piping should be sized to not have a greater than 4 ft of H2O pressure drop per 100 ft of pipe. 2675 Sizing the pipe smaller would increase the pressure drop through the pipe, increase the velocity 2676 through the pipe and allow for more erosion to occur. Sizing the pipe larger results in added pump 2677 savings, but will increase the installed cost of the pipe. 2678

Variable frequency drives on chillers can be used in applications where condenser relief 2679 occurs. Air-cooled condensers are typically designed for 95°F ambient air condition, and water-2680 cooled condensers are typically designed for 85°F enter water temperature. If the chiller will run a 2681 significant number of hours below these conditions, a VFD on the chiller should be considered. 2682 Generally, climates that are hot and humid all the time are not good candidates for VFD 2683 applications. 2684

Chilled water temperatures will vary depending on whether or not thermal storage is used. If 2685 thermal storage is used, it is important to pick the chiller efficiency for the hardest load it will see, 2686 which is typically during charge mode. Increasing chilled water range from the typical 10°F ∆T 2687 (or 2.4 gpm/ton) will save significant pump energy, however, it will affect cooling coil 2688 performance. This can be overcome by decreasing the chilled-water temperature to increase coil 2689


performance. Chilled water setpoints should be chosen based on the pump work, fan work, and 2690 desired cooling coil leaving-air temperature. 2691

Condenser water systems on water-cooled chiller applications should be sized for the flow of 2692 the condenser. ARI rating conditions of 3 gpm/ton apply for many typical applications and should 2693 be used. However, when the condenser head pressure is greater than 100 ft of H2O, a lower flow 2694 rate will save energy and should be considered. 2695

Chemical-less water treatment systems should be considered for the cooling tower system to 2696 minimize maintenance requirements. 2697 2698

HV25. Hot-Water Heating Systems (Climate Zones: all) 2699 Condensing boilers can operate up to 97% efficiency and operate efficiently at part load. To 2700

achieve these high efficiency levels, condensing boilers require return water temperatures be 2701 maintained in a range between 70°F to 120ºF, where the boiler efficiency is between 97% and 2702 91%. This fits well with hydronic systems that are designed with ∆T’s greater than 20ºF (optimal 2703 ∆T is 30ºF to 40ºF). The higher ∆T’s allow smaller piping and less pumping energy. Because 2704 condensing boilers work efficiently at part load, variable frequency drives can be used on the 2705 pumps to further reduce energy consumption. 2706

Condensing boiler capacity can be modulated to avoid losses due to cycling at less than full 2707 load. This encourages the installation of a modular (or cascade) boiler system, thus allowing 2708 several small units be installed for the design load, but allowing the units to match the load for 2709 maximum efficiency of the system. 2710 2711

HV26. Relief versus Return Fans (Climate Zones: all) 2712 Relief (rather than return) fans should be used when necessary to maintain building 2713

pressurization during economizer operation. Relief fans reduce overall fan energy use in most 2714 cases, as long as return dampers are sized correctly. 2715

However, if return duct static pressure drop exceeds 0.5 in. H2O, and a high percentage of the 2716 air is being exhausted during most hours of operation, return fans may be needed. 2717

2718

Cautions 2719

HV27. Heating Sources (Climate Zones: all) 2720 Forced-air electric resistance and gas-fired heaters require a minimum airflow rate to operate 2721

safely. These systems, whether stand-alone or incorporated into an air-conditioning or heat pump 2722 unit, should include factory-installed controls to shut down the heater when there is inadequate 2723 airflow, that can result in high temperatures. 2724

Ducts and supply-air diffusers should be selected based on discharge air temperatures and 2725 airflow rates. 2726

2727 HV28. Noise Control (Climate Zones: all) 2728

Much of the education that takes place in K–12 classrooms hinges on oral communication. 2729 Less-than-optimal acoustical conditions in the classroom affect the academic performance of all 2730 students, but they pose a particular challenge for students learning in a non-native language, 2731 coping with learning disabilities, or hindered by impaired hearing. 2732

Avoid installation of the HVAC equipment directly above classrooms. Consider locations 2733 above less critical spaces (such as storage areas, restrooms, corridors, etc.) or in acoustically-2734


treated closets adjacent to the space. Acoustical requirements may necessitate attenuation of the 2735 noise associated with the supply and/or return air, or noise radiated from the HVAC equipment. 2736 Acoustical concerns may be particularly critical in short, direct runs of ductwork between the fan 2737 and supply or return outlet. 2738

Refer to ASHRAE’s Practical Guide to Noise and Vibration Control for HVAC Systems for 2739 specific guidance by system type. 2740

2741 HV29. Proper Maintenances (Climate Zones: all) 2742

Regularly scheduled maintenance is an important part of keeping the HVAC system in 2743 optimum working condition. Neglecting preventive maintenance practices can quickly negate 2744 any energy savings expected from the system design. 2745

Filters should be replaced when the pressure drop exceeds the filter manufacturer’s 2746 recommendations for replacement, or when visual inspection indicates the need for replacement. 2747 Dampers, valves, louvers, and sensors must all be periodically inspected and calibrated to assure 2748 proper operation. This is especially important for outdoor-air dampers and CO2 sensors, if used. 2749 Inaccurate CO2 sensors can cause excessive energy consumption or poor indoor air quality, so 2750 these sensors need to be calibrated as recommended by the manufacturer. 2751

A building automation system can be used to notify maintenance personnel when preventive 2752 maintenance procedures should be performed. This notification can be triggered by calendar 2753 dates, run-time hours, the number of times a piece of equipment has started, or sensors installed 2754 in the system (such as a pressure switch that indicates when an air filter is too dirty and needs to 2755 be replaced). 2756 HV30. Zone Temperature Control (Climate Zones: all) 2757

The number of spaces in a zone and the location of the temperature sensor will affect the 2758 control of temperature in the various spaces of a zone. Locating the thermostat in one room of a 2759 zone with multiple spaces provides feedback based only on the conditions in that room. Locating 2760 a single thermostat in a large open area may provide a better response to the conditions of the 2761 zone with multiple spaces. Selecting the room or space that will best represent the thermal 2762 characteristics of the space due to both external and internal loads will provide the greatest 2763 comfort level. 2764

To prevent misreading of the space temperature, zone thermostats should not be mounted on 2765 an exterior wall. Where this is unavoidable, use an insulated sub-base for the thermostat. 2766

2767 HV31. Operable Windows (Climate Zones: 2B, 3-8) 2768

Compared to buildings with fixed-position windows, buildings with properly-applied and -2769 utilized operable windows can provide advantages in schools, including: 1) energy conservation 2770 and 2) energy conservation education (see also EN23). Natural ventilation, natural cooling, and 2771 passive solar heating can have positive sustainability effects. However, improper design and/or 2772 operation can have negative effects. Mechanical systems should be shut off when windows are 2773 opened. Control of operable window systems can be done manually or by interlock. Manual 2774 control provides the opportunity of energy efficiency education in the classroom, however, 2775 automatic controls (such as interlocks) are likely to save more energy. 2776

A bottom window and a top window should be opened at the same time. This allows the 2777 stack effect to setup a convection current of airflow when the difference between the indoor and 2778 outdoor temperatures is 10°F or more. 2779

The following table recommends setpoints for using operable windows: 2780 2781 2782


Controller Type Recommended Climate Zones

Cooling Setpoint Heating Setpoint

Measuring dry-bulb temperature only

B and C zones Window open when space temperature > outdoor temperature Window closed when space temperature < outdoor temperature

Window open when space temperature < outdoor temperature Window closed when space temperature > outdoor temperature

Measuring temperature and humidity

A zones Window open when space temperature and humidity > outdoor temperature and humidity Window closed when space temperature and humidity < outdoor temperature and humidity

Window open when space temperature < outdoor temperature Window closed when space temperature > outdoor temperature

2783 Using operable windows, and without proper sensor calibration, can create moisture or 2784

comfort problems and may reduce energy savings. 2785 2786 2787

References 2788 ASHRAE Handbook—HVAC Applications. Atlanta: American Society of Heating, Refrigerating 2789

and Air-Conditioning Engineers, Inc. 2790 ASHRAE Handbook—Fundamentals. Atlanta: American Society of Heating, Refrigerating and 2791

Air-Conditioning Engineers, Inc. 2792 ASHRAE Handbook—HVAC Systems and Equipment. Atlanta: American Society of Heating, 2793

Refrigerating and Air-Conditioning Engineers, Inc. 2794 ASHRAE. 2007. ASHRAE Standard 52.2-2007 - Method of Testing General Ventilation Air-2795

Cleaning Devices for Removal Efficiency by Particle Size. Atlanta: American Society of 2796 Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2797

ASHRAE. 2007. ASHRAE Standard 62.1-2007 - Ventilation for Acceptable Indoor Air Quality. 2798 Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2799

ASHRAE. 2005. Standard 62.1 User’s Manual. Atlanta: American Society of Heating, 2800 Refrigerating and Air-Conditioning Engineers, Inc. 2801

ASHRAE. 2007. ASHRAE Standard 90.1-2007 – Energy Standard for Buildings Except Low-2802 Rise Residential Buildings. Atlanta: American Society of Heating, Refrigerating and Air-2803 Conditioning Engineers, Inc. 2804

ASHRAE. 1988. ASHRAE Standard 111-1988 - Practices for Measurement, Testing, Adjusting, 2805 and Balancing of Building, Heating, Ventilation, Air-Conditioning and Refrigeration 2806 Systems. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning 2807 Engineers, Inc. 2808


ASHRAE. 2006. ASHRAE GreenGuide: The Design, Construction, and Operation of 2809 Sustainable Buildings. Atlanta: American Society of Heating, Refrigerating and Air-2810 Conditioning Engineers, Inc. 2811

Harriman, L., G. Brundett, and R. Kittler. 2001. Humidity Control Design Guide for Commercial 2812 and Institutional Buildings. Atlanta: American Society of Heating, Refrigerating and Air-2813 Conditioning Engineers, Inc. 2814

Mumma, S. and K. Shank. 2001. “Selecting the Supply Air Conditions for a Dedicated Outdoor 2815 Air System Working in Parallel with Distributed Sensible Cooling Terminal Equipment.” 2816 AT-01-7-3. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning 2817 Engineers, Inc.National Electrical Manufacturers Association, www.nema.org, Standards and 2818 Publications section. 2819

Schaffer, Mark. 2005. Practical Guide to Noise and Vibration Control for HVAC Systems. 2820 Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2821

SMACNA. 2002. HVAC Systems–Testing, Adjusting and Balancing. Chantilly, VA: Sheet Metal 2822 and Air Conditioning Contractors’ National Association, Inc. 2823

Service Water Heating 2824

Good Design Practices 2825

WH1 Service Water Heating Types (Climate Zones: all) 2826 This Guide assumes that the service water heating (SWH) equipment uses the same type of 2827

fuel source as is used for the HVAC system. This Guide does not cover systems that use oil, hot 2828 water, steam, or purchased steam for generating SWH, nor does it address the use of solar or site-2829 recovered energy (including heat pump water heaters). These systems are alternative means that 2830 may be used to achieve 30% (or greater) energy savings over ASHRAE Standard 90.1-1999 and, 2831 where used, the basic principles of this Guide would apply. 2832

The SWH equipment included in this Guide are the gas-fired water heater and the electric 2833 water heater. Both natural gas and propane fuel sources are available options for gas-fired units. 2834

There are many factors in making a decision whether to use gas or electricity, such as 2835 availability of service, operator familiarity, and so on. Efficiency recommendations for both 2836 types of equipment are provided to allow for choice by the user. 2837

2838 WH2 System Description (Climate Zones: all) 2839 1) Gas-fired storage water heater. A water heater with a vertical or horizontal water storage tank. 2840

A thermostat controls the delivery of gas to the heater’s burner. The heater requires a vent to 2841 exhaust the products of combustion. 2842

2) Gas-fired instantaneous water heater. A water heater with minimal water storage capacity. 2843 The heater requires a vent to exhaust the products of combustion. An electronic ignition is 2844 recommended to avoid the energy losses from a standing pilot. 2845

3) Electric resistance storage water heater. Water heater consisting of a vertical or horizontal 2846 storage tank with one or more immersion heating elements. Thermostats controlling heating 2847 elements may be of the immersion or surface-mounted type. 2848

4) Electric resistance instantaneous water heater. Compact, under-cabinet, or wall-mounted 2849 types with insulated enclosure and minimal water storage capacity; a thermostat controls the 2850 heating element, which may be of the immersion or surface-mounted type. Instantaneous, point-2851 of-use water heaters should provide water at a constant temperature regardless of input water 2852 temperature. 2853

2854


WH3 Sizing (Climate Zones: all) 2855 The water heating system should be sized to meet the anticipated peak hot water load. The 2856

hot water demand will be calculated based upon the sum of the building fixture units according 2857 to local code. 2858

Local and state plumbing codes for water closets vary and range from 1 per 20-25 elementary 2859 female students to 1 per 30-45 secondary female students, and 1 per 30 elementary male students 2860 to 1 per 40-90 secondary male students. Lavatories in the restrooms are generally in the ratio of 1 2861 per 2 water closets installed in a general restroom. Note that in many elementary schools, wet 2862 areas are provided in K-2 classrooms with hot water for hand washing. Some state codes and 2863 educational specifications may require sinks with hot water in laboratories, workshops, 2864 vocational classrooms, and art rooms. 2865

Hot water temperature for restrooms and other academic areas of a school varies by local and 2866 state code, within the range of 100°F to 120°F. Hot water is also a requirement in the school 2867 kitchen with a delivered temperature between 120°F and 140°F. Booster heaters are used on the 2868 dishwashers bringing the temperature to required 160°F to 180°F for sanitation. 2869

Showers are normally specified in elementary health/nurse rooms. Showers are normally 2870 specified for physical education locker rooms in secondary schools. In larger secondary schools, 2871 team sport areas may require shower areas. The temperature of the hot water provided to the 2872 showers should range from 100°F to 110°F. 2873

In the design and evaluation of the most energy-efficient hot water system for a school, and 2874 the life cycle cost associated with it, consideration should be given to the installation of tank-less 2875 hot water heaters at most locations in the school. Only areas of the school where large volumes 2876 of hot water are required (such as the cafeteria, gymnasium, and culinary vocational classrooms) 2877 should large hot water heaters or smaller circulating hot water systems be installed. 2878

2879 WH4 Equipment Efficiency (Climate Zones: all) 2880

Efficiency levels are provided in the climate-specific tables in Chapter 3 for the four types of 2881 water heaters listed in WH2. 2882

The gas-fired storage water heater efficiency levels correspond to condensing storage water 2883 heaters. High-efficiency, condensing gas storage water heaters (energy factor > 0.90 or thermal 2884 efficiency > 0.90) are alternatives to the use of gas-fired instantaneous water heaters. 2885

For gas-fired instantaneous water heaters, the energy factor and thermal efficiency levels 2886 correspond to commonly available instantaneous water heaters. 2887

Electric storage water heater efficiency should be calculated as 0.99 – 0.0012 × water heater 2888 volume. 2889

Instantaneous electric water heaters are an acceptable alternative to high-efficiency storage 2890 water heaters. Electric instantaneous water heaters are more efficient than electric storage water 2891 heaters, and point-of-use versions will minimize piping losses. However, their impact on 2892 building peak electric demand can be significant and should be taken into account during design. 2893 Where unusually high hot water loads (e.g., showers or laundry facilities), are present during 2894 peak electrical use periods, electric storage water heaters are recommended over electric 2895 instantaneous for those end uses. 2896

2897 WH5 Location (Climate Zones: all) 2898

The water heater should be located close to the hot water fixtures to avoid the use of a hot 2899 water return loop or the use of heat tracing on the hot water supply piping. Where electric 2900 resistance heaters are used, point-of-use water heaters should be considered when there is a low 2901 number of fixtures or where they can eliminate the need for a recirculating loop. 2902


2903 WH6 Pipe Insulation (Climate Zones: all) 2904

All SWH piping should be installed in accordance with accepted industry standards. 2905 Insulation levels should be in accordance with the recommendation levels in the climate-specific 2906 tables in Chapter 3, and the insulation should be protected from damage. Include a vapor 2907 retardant on the outside of the insulation. 2908

2909

2910

References 2911 ASHRAE Handbook—HVAC Applications. Atlanta: American Society of Heating, Refrigerating 2912 and Air-Conditioning Engineers, Inc. 2913

Additional Savings 2914 AS-1 Electrical Distribution System (all Climate Zones) 2915 The size of an educational building is a contributing factor in the determination of the electrical 2916 voltage service brought into the building. Electrical service from the utility in smaller schools is 2917 usually 120/208 3 phase voltage and in larger schools 277/480 voltage 3 phase. When the 2918 277/480 volt service is provided, then 120/208 volt dry step down transformers are placed in key 2919 locations in the building to provide the power to the electrical outlets throughout the school. 2920 Electrical distribution systems in today’s schools contribute to the energy inefficiency and the 2921 following good practices will assist with improving the energy efficiency of the electrical 2922 distribution system. 2923

Electrical Service Voltage – School facilities with an area of less than 40,000 square feet should 2924 design the incoming electrical service from the utility for 120/208 volts. Schools facilities larger 2925 than 40,000 square feet should have the incoming electrical service designed from the utility at 2926 277/480 volts. This design will require the placement of internal step down dry transformers 2927 277/480 V to 120/208 V to provide the needed power for the plug load. 2928

Energy Efficient Transformers – U.S. Department in Energy has recognized current step down 2929 transformers contribute to energy waste throughout the country. The CSL-3 standard has been 2930 established for improving the energy efficiency of distribution transformers when used. This 2931 standard recognizes the low loading which exists especially in schools and the no-load losses 2932 existing with current transformer design. This standard CSL-3 design eliminates any impact for 2933 normal harmonics created by the loads within the school. Concentrating all larger computer 2934 loads on one transformer can be handled by a variation in the CSL-3 design and still keep the 2935 efficiencies and no-load losses required. The standard includes specifics as to the no-load losses 2936 for specific sized transformers and specific percent efficiencies at given loadings. For example a 2937 CSL-3 75 KVA 277/480 to 120/208 volt transformer maximum no load losses is 170 watts/hour 2938 versus the current industry average of over 850 watts/hour. This same transformer will meet or 2939 exceed 98.4 % efficiency at 1/6 loading. The efficiency of the standard transformers currently 2940 specified at 1/6 loading is in the 80-85% range. See Appendix D for more specifics. This is an 2941 unregulated load at this time. At current use of distribution transformers in schools and average 2942 electrical energy cost in the nation the following illustrates the potential energy savings when 2943 specifying and installing energy efficient transformers: Typical 73,000 SF Elementary School -- 2944 $9000/year and over a $400,000 during a 50 year life of the building; Typical Middle School -- 2945 $13000/year and over $600.000 over the life of the building; and for a typical High School -- 2946


$20,000/year or over $1 million over the life of the building. The 50 year life figures do not 2947 include any rate increase during the period. 2948

Current Codes and Testing– The NEC contributes to the energy inefficiency of the electrical 2949 distribution system by requiring enough power for all the electrical outlets installed as if those 2950 electrical outlets were being used by linear loads (incandescent lamps, electric heaters, overhead 2951 projectors, etc.). This assumes all outlets will be used at the same time and the maximum for the 2952 circuit. In today’s schools most the loads, more than 75%, in offices and classrooms are non-2953 linear loads (Computers, printers, copiers, smart boards, LCD projectors, microwaves, etc.). 2954 Testing of existing electrical distribution systems (step down transformers) in schools indicate 2955 the loading is between 5 to 20% of it capacity. Downsizing of transformer design from 33% to 2956 50% would not only reduce energy waste but would reduce the limited resources used in 2957 manufacturer – copper, steel, etc. In the design of new schools, recommend testing of the 2958 distribution transformers in a similar size school be accomplished at the same time testing is 2959 being accomplished before design begins. This will provide you the needed data for code 2960 officials to review and conclude the downsizing of the transformers which are included in the 2961 project is needed and appropriate. 2962

Specification of Energy Efficient Transformers -- Energy Efficient transformers should be 2963 specified using the CSL-3 Standard of DOE as the basis. Specifications must include maximum 2964 no-load losses for specified transformers sizes and percent efficiency at 16.7% loading. Included 2965 in the specifications must be the statement that test data for the transformers being provided must 2966 accompany the bid submission. Normally electrical distribution equipment is provided by one 2967 supplier. This means the cost of the transformer is “buried” in the electrical distribution 2968 equipment price. Recommend the following be included in the bid specifications “The bid price 2969 for the dry distribution transformers specified (277/480 to120/208Volt) must be identified 2970 separately (priced) within the electrical bid and can not be included in the bid pricing for other 2971 electrical distribution equipment that falls under Section 16 of the Standard AIA Specification 2972 Structure. If specified transformers are not separately identified in the bid pricing then the entire 2973 bid will be disqualified”. 2974

AS-2 Plug and Phantom Loads (all climate Zones) 2975 Plug Loads -- Plug loads are devices or appliances that plug into a school’s electrical system. A 2976 school typically has a 120/208 volt electrical system and includes many different “loads.” A 2977 load is anything that draws power from the system and requires electricity to do work. Plug 2978 loads found in schools include the following: Computers, DVD players, VCRs, Overhead and 2979 LCD projectors, Boom Boxes, CD Players, Printers, Scanners, Copiers, Fax Machines, Radios, 2980 Microwaves, coffee pots, popcorn poppers, fish tanks, desk top lights, stoves, refrigerators of all 2981 sizes, vending machines, smart boards, vocational equipment and tools, soda machines, drinking 2982 fountains, and many other devices for educational purposes and for comfort of the individual. 2983

Phantom Loads – A VCR placed into a classroom has been flashing “12:00 am” since it was 2984 installed four years ago. The only time it has not been flashing is when a power outage occurred 2985 last winter. This is a prime example of an electronic device in today’s classrooms which 2986 consume energy when the switch indicates it is off. This consumption of electrical energy is 2987 classified as a “Phantom Load”. Phantom Loads are also known as “Standby Power” or 2988 “Leaking Electricity”. Phantom loads usually exist with any electronic or electrical device or 2989 appliance many of which are found in schools. Equipment with electronic clocks or timers, with 2990 remote controls, portable equipment and office equipment with wall cubes (a small box that 2991 plugs into an AC outlet to charge cell phones for provide power to computers) all of these have 2992 Phantom loads. Phantom loads can consume up to 5% of your electrical plug load. 2993


Control on Plug Loads -- Plug Loads contribute up to 25% of the electrical load in a school. This 2994 determination has resulted from plug load surveys in schools conducted over the past several 2995 years. Plug loads can contribute between 0.6 and 1.0 watts / SF in energy use annually. A large 2996 part of this electrical load results from electrical equipment and appliances left on after use and 2997 also contain a “phantom” load when not in use. To reduce this load potential consideration 2998 should be given to controlling the top outlet of each duplex outlet with the occupancy sensor 2999 used to control the lighting the room. This is in addition to the need for a personal appliance 3000 policy by the school district and constant energy awareness training on use of equipment and 3001 appliances in a school. The inclusion of this feature in future designs would reduced the plug 3002 load density from the current 0.6 to 1.0 watt to 0.4 to 0.6 watts per hour per square foot annually. 3003 For a 100,000 square foot school this would mean a reduction of between 20 to 40 KW per hour. 3004

3005

Side Bar Technology Case Study: 3006 ENERGY STAR Power Management features — standard in Windows and Macintosh 3007 operating systems — place inactive monitors and computers (CPU, hard drive, etc.) into a 3008 low-power sleep mode. A simple touch of the mouse or keyboard “wakes” the computer 3009 and monitor in seconds. 3010

Monitor power management (MPM) can save $10 to $30 per monitor annually by 3011 placing your inactive monitors into a low-power sleep mode. 3012

Computer power management (CPM) places inactive computers (CPU, hard drive, 3013 etc.) into a low-power sleep mode, which can save $15 to $45 per desktop computer 3014 annually. 3015

http://www.energystar.gov/index.cfm?c=power_mgt.pr_power_management3016

Read about how North Thurston Public Schools is saving $45,000 annually by activating 3017 computer and monitor sleep settings 3018

3019

Control of Phantom Loads -- The best direct means of controlling phantom loads is to unplug the item 3020 if possible when not in use like a TV and other similar items. In lieu of directly unplugging the item 3021 all these items needed to be plugged into a power strip and the power strip switched off when leaving 3022 the classroom each day, over the weekend, holidays and vacations periods. 3023 3024 Energy Star Appliances/equipment – A School Board policy should be approved which states 3025 that all electrical equipment and appliances placed in a school will have the Energy Star Label if 3026 Energy Star has rated the equipment or appliance. See Appendix D for those items having 3027 energy star ratings. The recommendations presented in Table 5-2 for purchase and operation of 3028 plug load equipment are an integral part of this Guide, but the energy savings from the plug load 3029 recommendations are expected to be in addition to the target 30% savings. 3030


3031

Table 5-2. Recommendations for Efficient Plug Load Equipment

Equipment/Appliance Type Purchase Recommendation Operating Recommendation

Desktop computer ENERGY STAR® only Implement sleep mode software

TV/VCR Purchase with flat-screens with sleep modes

Many of these items are only used during peak times and should be unplugged with occupancy sensors

Laptop computer—use where practical instead of desktops to minimize energy use

ENERGY STAR® only Implement sleep mode software

Computer monitors ENERGY STAR® flat-screen monitors only

Implement sleep mode software

Printer ENERGY STAR® only Implement sleep mode software

Copy machine ENERGY STAR® only Implement sleep mode software

Fax machine ENERGY STAR® only Implement sleep mode software

Water cooler ENERGY STAR® only N/A

Refrigerator ENERGY STAR® only N/A

Vending machines ENERGY STAR® only Delamp display lighting

TV/VCR ENERGY STAR® only

3032

AS-3 Ground-Source Heat Pumps (Climate Zones: all) 3033 A variation of the water-source heat pump system (see HV2) takes advantage of the relatively-3034 constant temperature of the earth, and uses the ground instead of the cooling tower and boiler. 3035 Ground-source heat-pump (GSHP) systems do not actually get rid of heat, they store it in the 3036 ground for use at a different time. During the summer, the heat pumps extract heat from the 3037 building and transfer it to the ground. When the building requires heating, this stored heat can be 3038 recaptured from the ground. In a perfectly balanced system, the amount of heat stored over a 3039 given period of time would equal the amount of heat retrieved. 3040

Ground-source heat pump systems offer the potential for saving energy because they can reduce 3041 (or eliminate) the energy needed to operate a cooling tower and/or boiler. Eliminating the 3042 cooling tower also has architectural and maintenance advantages, and eliminating the boiler frees 3043 up floor space in the building. 3044


While eliminating both the cooling tower and boiler likely results in the greatest overall energy 3045 savings, for most applications it requires the largest (and more expensive) geothermal heat 3046 exchanger to account for the imbalance between heat stored and heat extracted. 3047

For example, in a cooling-dominated climate, a large amount of heat must be rejected to the 3048 ground during the cooling season, but a much smaller amount of heat is extracted from the 3049 ground during the heating season. This imbalance can cause the temperature of the ground 3050 surrounding the geothermal heat exchanger to increase over time. 3051

Conversely, in a heating-dominated climate, a relatively small amount of heat is rejected to the 3052 ground during the cooling season, but a much larger amount of heat must be extracted back out 3053 of the ground during the heating season. In this case, the temperature of the ground can decrease 3054 over time. In either case, future operation of the heat pumps is compromised by this change in 3055 ground temperature. 3056

In many areas of the country, this imbalance requires the geothermal heat exchanger to be larger 3057 to prevent the ground temperature from changing over time. The first cost to install such a large 3058 heat exchanger often dissuades people from considering this approach. Using a "hybrid" 3059 approach, however, can often make GSHP systems more economical, opening up the possibility 3060 to reap the potential energy savings. 3061

This "hybrid" approach involves adding a small cooling tower to the loop for a system that is 3062 installed in a cooling-dominated climate, or adding a small boiler to a system in a heating-3063 dominated climate. In either case, the geothermal heat exchanger is sized based on the smaller of 3064 the two loads: for the total heat absorbed in a cooling-dominated climate or the total heat rejected 3065 in a heating-dominated climate. Then, a small cooling tower (or boiler) is added to reject (or add) 3066 the remaining heat. 3067

This approach reduces the required size of the geothermal heat exchanger by avoiding the 3068 imbalance described previously. While the overall energy savings may not be as great as in a 3069 system with a larger heat exchanger, this approach often results in a more acceptable return on 3070 investment. 3071

3072

AS-4 Thermal Storage (Climate Zones: all) 3073

Adding thermal storage to an HVAC system can reduce the utility costs associated with cooling 3074 by shifting operation of the chiller from times of high-cost electricity (daytime) to times of low-3075 cost electricity (nighttime). This avoids, or reduces, the electricity required to operate the chiller 3076 during the daytime hours. Operation of the chiller is shifted to the off-peak period, during which 3077 the cost of electricity is lower and the demand charge is lower or non-existent. The chiller is used 3078 during that period to cool or freeze water inside storage tanks, storing the thermal energy until 3079 the on-peak period. 3080

During the nighttime hours, both the outdoor dry-bulb and wet-bulb temperatures are typically 3081 several degrees lower than during the day. This lowers the condensing pressure, allowing the 3082 chiller to regain some of the capacity and efficiency it lost by producing colder fluid 3083 temperatures to recharge the storage tanks. 3084

Another potential benefit of thermal storage is a reduction in the size and capacity of the 3085 chiller(s). When thermal storage is used to satisfy all or part of the design cooling load, the 3086 chiller may be able to be downsized as long as the downsized chiller has sufficient time to 3087 recharge the storage tanks. 3088


3089

AS-5 Thermal Displacement Ventilation (Climate Zones: all) 3090 Thermal displacement ventilation (TDV) systems are different from conventional, overhead air 3091 delivery systems. TDV systems delivered air near the floor, at a low velocity, and at a 3092 temperature of about 65ºF (compared to around 55ºF with overhead air delivery). The goal of 3093 TDV systems is not to cool the space, but to cool the occupants. Cool air flows along the floor 3094 until it finds warm bodies. As the air is warmed, it rises around occupants, bathing them in cool 3095 fresh air. 3096

Air quality improves because contaminants from occupants and other sources tend to rise out of 3097 the breathing zone rather than being mixed in the space. Similarly, cooling loads decrease 3098 because much of the heat generated by occupants, lights, and computer equipment rises directly 3099 out of the occupied zone and is exhausted from the space. (This is especially true in classrooms 3100 designed for 100% outdoor air.) 3101

TDV is most appropriate for spaces with a ceiling height greater than 10 ft to permit temperature 3102 stratification. However, heating performance may be worse than systems that deliver air at 3103 greater velocities, since mixing (not stratification) is desirable for heating. In non-arid climates, 3104 the supply air must be sufficiently dehumidified before it is reheated, or mixed with warm return 3105 air, to achieve the desired 65ºF supply-air temperature. 3106

3107

AS-6 Photovoltaic Systems 3108 Photovoltaic Systems (PV) have become an increasingly popular option for energy production 3109 and for a teaching opportunity in schools. Currently, most of the PV systems that are being used 3110 in schools are relatively small in comparison to the total energy usage of the school, this mainly 3111 due to the initial cost of the PV system. Most PV systems in K-12 schools range from a 1kW to 3112 50kW system. An example of a school using a larger system is Williamstown Elementary 3113 School in Williamstown, Massachusetts. Williamstown Elementary has a 24kW roof mounted 3114 PV system. The system at Williamstown is estimated to produce roughly 30,000 kWh of 3115 electricity per year, which equates to about 5%-10% of the schools annual consumption. The 3116 actual energy production can be monitored at the following website: 3117 http://soltrex.masstech.org/systems.cfm?systemid=S00000000228&sortby=site&ascdesc=asc&startrow=43118 1&watchid=SW0000000041. 3119 3120 PIC 3121 24kW PV system at Williamstown Elementary, Williamstown, MA 3122 3123 Another example of a school using a large PV system to generate a significant energy savings is 3124 the Head-Royce School in Oakland, California. The school installed a 53kW PV system on the 3125 roof of the gymnasium. The system leads to a 25% savings in the electricity bill for the middle 3126 school and gymnasium. 3127

3128 PIC 3129 53kW PV system at Head-Royce School, Oakland, CA 3130 3131


The smaller PV systems are typically used for more of a teaching device. Smaller systems are 3132 usually installed in plain view in order to make them visible to the students, teachers and the 3133 community surrounding the school. It is an attempt to inform the public of the importance of 3134 renewable energy sources and the technology involved. Small systems can be mounted in such a 3135 way that they have an addition purpose. Fossil Ridge High School in Fort Collins is an example 3136 of a school that uses a smaller PV system. The 5.2kW PV system at Fossil Ridge is mounted 3137 outside of the south entrance on frames in front of the windows. The PV panels act as overhangs 3138 for the windows. Another example of a school using a small PV system is Zeeland West High 3139 School in Zeeland Michigan. The system is a 1kW system that is mounted on poles on the 3140 ground. This aids in using the PV system as a teaching device. 3141

3142 3143 3144 PIC PIC 3145 5.2kW PV System at Fossil Ridge 1kW PV System at Zeeland 3146 High School, Fort Collins, CO West High School, Zeeland, MI 3147 3148 There are many unique funding opportunities for PV systems in schools. In additional to the 3149 many rebate programs offered by state and local utility companies, there are often significant 3150 incentives, loans, grants, and buyback programs for PV systems for K-12 schools. The following 3151 link gives a break down of some of the incentives and rebates that are available to schools in 3152 most of the states in the United States, http://www.dsireusa.org/Index.cfm?EE=0&RE=1. Some 3153 state and local utility companies offer rebates that range from $2.00 per watt to $6.00 per watt 3154 for PV systems for schools. . 3155

AS-7 Energy Efficient Schools as a Teaching Tool 3156 Schools incorporating energy-efficiency and renewable energy technologies make a strong 3157 statement about the importance of protecting the environment. They also provide hands-on 3158 opportunities for students and visitors to learn about these technologies and the importance of 3159 energy conservation. The efforts to make a school building energy efficient have become more 3160 and more evident and are no longer being hidden within the walls and mechanical rooms. 3161 Energy efficient techniques used in the school buildings are being used as teaching aides in the 3162 schools, and teachers have introduced curriculum that focuses on energy usage and 3163 environmental issues. 3164

A common area of interest in the newly designed schools and curriculums is photovoltaic 3165 systems. Elmira High School in Elmira, Oregon is a good example of how a school uses PV in 3166 their teaching curriculum. Elmira is one of fifteen schools in Oregon that is participating in a 3167 pilot PV program started by the Bonneville Power Administration (BPA) and Western SUN 3168 (WSUN). Elmira has a 0.6kW PV system that is used as a teaching aide. The University of 3169 Oregon has put together a series of lesson plans for the schools that are participating in the 3170 program. The first of the three lessons plans introduces the students to the basic physics and 3171 chemistry that occurs in a solar cell 3172 (http://solardata.uoregon.edu/download/Lessons/PVLessonPlan1SolarCells.pdf.) In the second 3173 lesson plan, the students are shown the components of a solar electric system and the concept of 3174 a PV IV curve 3175 (http://solardata.uoregon.edu/download/Lessons/PVLessonPlan2SolarElectricArrays.pdf.) In the 3176 final lesson plan, students are taught about some of the variables that influence the effectiveness 3177 of the PV arrays in generating electricity 3178


(http://solardata.uoregon.edu/download/Lessons/PVLessonPlan3PVArrayGeneratingElectricity.p3179 df.) Elmira, as well as the other fourteen schools, can gather real time information on the PV 3180 arrays at the following link http://www.bpa.gov/Energy/n/tech/EEMeteringData/SolarSchools/. 3181

3182 Many of the schools that have installed PV’s have instituted programs for the students that allow 3183 them to monitor the real time PV system performance. The monitoring programs are typically 3184 available through kiosks in the school or via the internet. Some examples of the monitoring 3185 systems are available at the following links: 3186

http://www.matchschool.org/solar/rtd.html3187

http://soltrex.masstech.org/systems.cfm?systemid=S00000000228&sortby=site&ascdesc=asc&st3188 artrow=41&watchid=SW00000000413189

http://66.189.87.227/tfhs01/tfhsweb/rtd.html3190

http://www.sunviewer.net/portals/MSGS/3191

http://www.energywhiz.com/index.htm3192

http://desertedge.greentouchscreen.com/3193

http://northcharleston.greentouchscreen.com/3194

3195 Twenhofel Middle School in Independence, Kentucky is an excellent example of a school using 3196 the green building techniques as a teaching aide. The students are able to monitor most of the 3197 systems that are used in the school through the online monitoring program at the following site 3198 http://www.twhvac.kenton.kyschools.us/. The website allows the students to monitor the 3199 electrical energy, PV system, daylighting system, geothermal heating and cooling system and the 3200 rainwater harvesting system. The program makes students aware of their daily energy usages, 3201 and an opportunity for a hands-on learning experience with renewable energy. In the science 3202 classes, the students use the monitoring program to track the effects on daylighting from the sun. 3203 This teaches the students the patterns of the sun and earth throughout the course of a year. At 3204 Twenhofel, students are encouraged to conserve energy. The school has a monthly contest 3205 between the 6th, 7th and 8th grade students to see which grade can conserve the most energy over 3206 the course of a month. The students track their progress in the monthly contest every morning 3207 via a television mounted in the lobby. 3208

PIC 3209 Clerestory windows and 24kW PV system used at Twenhofel Middle School, Independence, KY 3210

3211 Schools are including more than just PV systems. Some schools have left HVAC equipment and 3212 plumbing exposed to allow the students to see the systems. The exposed systems are used to 3213 teach students. Zach Elementary School in Fort Collins is an example of a school that has left 3214 building systems exposed to teach students. Some of the piping in the school is left exposed. At 3215 Zach Elementary, 100% of the electricity used in the school is purchased from wind power. 3216 Inside the school, there is miniature wind turbines mounted to the walls. The turbines are used to 3217 increase the awareness of the growing wind energy presence in Fort Collins. There are also 3218 places in the school where the walls have cutouts that allow the students to see inside the walls. 3219 The cutouts allow the students to learn about the techniques used in the construction of the 3220 building that make it energy efficient. 3221


3222

3223 sulation, and example wind turbines, 3224

udre School District, Fort Collins, CO 3225 Exposed piping, and in

Zach Elementary, Po


Appendix A Envelope Thermal Performance Factors 3226 The climate zone tables present the opaque envelope recommendations in a standard format. 3227 This is a simple approach, but it limits the construction options. In order to allow for alternative 3228 constructions, the recommendations can also be represented by thermal performance factors such 3229 as U-factors for above-grade components, C-factors for below-grade walls, or F-factors for slabs-3230 on-grade; see Table A-1. Any alternative construction that is less than or equal to these thermal 3231 performance factors will be acceptable alternatives to the recommendations. 3232

Table A-1 Envelope Thermal Performance Factors 3233 Item Description Unit #1 #2 #3 #4 #5 #6

Insulation entirely above deck R 15 20 30

U 0.063 0.048 0.032

Metal Building R 19 13+13 13+19

U 0.065 0.055 0.049

Attic and Other R 30 38 49

U 0.034 0.027 0.017

Single Rafter R 30 38 38+5 38+10

Roof

U 0.036 0.028 0.024 0.022

Mass R 5.7 7.6 9.5 11.4 15.2

U 0.151 0.123 0.104 0.090 0.071

Metal Building R 13 13+13 13+16

U 0.113 0.057 0.055

Steel Framed R 13 13+3.8 13+7.5 13+22

U 0.124 0.084 0.064 0.040

Wood framed and Other R 13 13+3.8 13+7.5 13+10

Walls,

Above

Grade

U 0.089 0.064 0.051 0.045

Below-Grade Walls R 7.5 15 Below Grade C 0.119 0.063

Mass R 4.2 6.3 8.3 10.4 12.5 16.7

U 0.137 0.107 0.087 0.074 0.064 0.051

Steel Joist R 19 30 38

U 0.052 0.038 0.032

Wood Framed and Other R 19 30

Floors

U 0.051 0.033

Unheated R-in. 10-24 15-24 20-24

F 0.540 0.520 0.51

Heated R-in. 7.5-12 7.5-24 10-36 15 Full 20 Full

Slabs

F 0.60 0.56 0.51 0.30 0.261


Appendix B Additional Resources 3234 (to be determined. Intent of the section is to provide additional reading.) 3235

3236


Appendix C Commissioning and Quality Assurance 3237 Quality and performance are never an accident. It is always the result of high intention, sincere 3238 effort, intelligent direction, and skilled execution. A high quality building that functions in 3239 accordance with its design intent, and thus meets the performance goals established for it, 3240 requires that quality assurance be an integral part of the design and construction process. This 3241 process is typically referred to as commissioning. 3242

Commissioning requires a dedicated person, with no other project responsibilities, who can 3243 execute a systematic process that verifies that the installed systems and assemblies perform as 3244 required. An independent party is needed to ensure that the strategy sets and recommendations 3245 contained in this guide meet the owners stated requirements. That independent party may be 3246 from within your organization, a 3rd party commissioning professional or a capable member of 3247 the installing contractor, architect or engineer of record. 3248

While the commissioning process is applicable to all buildings, large and complex buildings 3249 require a correspondingly greater level of effort than is required for small, simple buildings. The 3250 commissioning process is critical to school buildings in order to achieve and maintain goals such 3251 as improvements in test scores, more resources in the classrooms, less operational costs, etc. The 3252 following recommended commissioning practices will help to meet these objectives. 3253


3254

Table C-1 Commissioning Activities and Responsibilities 3255 Item Activity Responsibility

1. Create Owner’s Project Requirements Owner/consultant

2. Create Project Specific Commissioning Plan (use this model, modify where necessary)

Owner/consultant

3. Create the Basis of Design Architect/Engineer

4. Review Owner’s Project Requirements and Basis of Design Commissioning agent

5. Review Schematic and Design Development Documents. Commissioning agent

6. Review Construction Documents prior to completion. Commissioning agent

7. Incorporate commissioning requirements into construction documents. Arch/Eng

8. Review submittals for commissioned systems. A/E; Commissioning agent

9. Develop project-specific construction checklists. Commissioning agent

10. Implement construction checklists Contractors

11. Create and maintain commissioning issues log Commissioning agent

12. Perform targeted inspections during rough-in phase. Commissioning agent /AE/ M&O

13. Witness pipe flushing and testing, duct testing Commissioning agent

14. Field-verify Contractors’ completed construction checklists. Commissioning agent /M&O

15. Support Commissioning Team during performance testing and demonstrations

Contractors

16. Validate Test and Balance report. Commissioning agent

17. Conduct periodic commissioning meetings. Commissioning agent

18. Develop functional performance test procedures. Commissioning agent

19. Assist in contractor troubleshooting. Commissioning agent

20. Identify air quality issues. Commissioning agent

21. Direct and witness functional performance testing. Commissioning agent /M&O

22. Issue final commissioning report. Commissioning agent

23. Develop systems manuals from M&O manuals including re-commissioning procedures.

Commissioning agent

24. PM Coordinate and document Owner training performed by contractors. PM

25. Confirm training performed by Contractors is per contract and adequate. Commissioning agent /M&O

26. Recommend final system acceptance. Commissioning agent /AE/ M&O

27. Perform post-occupancy review 2 months after occupancy. Commissioning agent /PM/FP/ M&O

28. Perform post-occupancy review and warranty inspections 10 months after occupancy per contract documents

Commissioning agent /PM/FP/ M&O/Architect

29. Create lesson-learned document for distribution to all WCPSS project managers/planners.

Commissioning agent


Appendix D Energy Efficient Equipment 3256

Energy Star Appliances 3257

The following equipment and appliances within the scope of the applicable Energy Star program 3258 shall have the Energy Star label:3259

(a) appliances 3260 1. battery chargers 3261 2. clothes washers 3262 3. dehumidifiers 3263 4. dishwashers 3264 5. refrigerators and freezers 3265 6. room air conditioners (see also the energy efficiency requirements) 3266 7. room air cleaners 3267 1. water coolers 3268

(b) heating and cooling 3269 1. air-source heat pumps (see also the energy efficiency requirements) 3270 2. boilers (see also the energy efficiency requirements) 3271 3. central air conditioners (see also the energy efficiency requirements) 3272 4. ceiling fans 3273 5. dehumidifiers 3274 6. furnaces (see also the energy efficiency requirements) 3275 7. geothermal heat pumps (see also the energy efficiency requirements) 3276 8. light commercial 3277 9. programmable thermostats 3278 10. room air conditioners (see also the energy efficiency requirements) 3279 11. ventilating fans 3280

(c) electronics 3281 1. cordless phones 3282 2. combination units (TV/VCR/DVD) 3283 3. DVD products 3284 4. audio 3285 5. televisions 3286 6. VCRs 3287

(d) office equipment 3288 1. computers 3289 2. copiers 3290 3. fax machines 3291 4. laptops 3292 5. mailing machines 3293 6. monitors 3294 7. multifunction devices 3295 8. printers 3296


9. scanners 3297 (e) lighting 3298

1. compact fluorescent light bulbs (CFLs) 3299 2. ceiling fans 3300

(f) commercial food service 3301 1. commercial fryers 3302 2. commercial hot food holding cabinets 3303 3. commercial solid door refrigerators and freezers 3304 4. commercial steam cookers 3305

(g) other products 3306 1. traffic signals 3307 2. transformers 3308 3. vending machines 3309

3310

Energy Efficient Transformers 3311

Energy efficient distribution transformers should be provided in construction/repair projects 3312 whether for new, renovation or replacement projects. Minimum transformer specifications as of 3313 January 1, 2007 are classified by the U.S. Department of Energy (U.S. DOE) as TP-1 and are the 3314 lowest efficiency available. Energy efficient transformers that are 30% more efficient than the 3315 minimum TP-1 are classified by the U.S. DOE as CSL-3. The following are key performance 3316 specifications by which an energy efficient transformer should be evaluated for any project in 3317 which they are specified. 3318

3319

SECTION 16461 – DRY TYPE TRANSFORMERS WITH U.S. DEPARTMENT 3320 OF ENERGY CSL 3 EFFICIENCY 3321

PART 1 GENERAL 3322 1.1 WORK INCLUDED 3323

A. Copper-wound transformer meeting US Department of Energy proposed Candidate 3324 Standard Level (CSL) 3 efficiency, extremely low no load losses, with integrated 3325 sustained total electrical protection. 3326

B. Load Mix: Transformer shall be UL listed to feed a mix of equipment load profiles 3327 such as computers without de-rating or significant degradation of efficiency. 3328

1.2 REFERENCES 3329

A. FEDERAL REGISTER – US Department of Energy, Office of Energy Efficiency 3330 and Renewable Energy. 10 CFR Part 430, July 29, 2004. Energy Conservation 3331 Program for Commercial and Industrial Equipment: Energy Conservation Standards 3332 for Distribution Transformers; Proposed Rule 3333

B. ANSI/NEMA ST 20 - Dry Type Transformers for General Applications. 3334

C. ANSI/NEMA TP-1 – Guide for Determining Energy Efficiency for Distribution 3335 Transformers 3336 a. For Reference only. US DOE does not consider NEMA TP-1 efficiency levels 3337

to reflect low life cycle cost. Transformers in this specification are substantially 3338 more efficient than NEMA TP-1 levels, meeting US Department of Energy 3339


proposed Candidate Standard Level (CSL) 3 efficiency. 3340

D. ANSI/NEMA TP-2 – Standard Test Method for Measuring Energy Consumption of 3341 Distribution Transformers 3342

E. Metering Standards: 3343

a. Computational algorithms per IEEE Std 1459-2000 3344

b. UL 916, UL 61010C-1 CAT III 3345

F. IEEE C57.110-1998 – IEEE Recommended Practice for establishing transformer 3346 capability when feeding non-sinusoidal load currents 3347

G. IEEE-1100 – Recommended Practice for Powering and Grounding Sensitive 3348 Electronic Equipment 3349

a. IEEE Standard 1100 documents how typical transformers feeding electronic 3350 equipment produce substantially higher losses under electronic equipment load 3351 compared to under linear load, requiring derating. 3352

H. ISO 9000 – International Standards Organization - Quality Management System 3353

I. ISO 14000 – International Standards Organization - Environmental Management 3354 System 3355

1.3 SUBMITTALS 3356

A. Submit product data including the following: 3357 a. Copy of ISO 14001 Certification of manufacturing operation. 3358 b. Copy of ISO 9001 Certification of manufacturing operation. 3359 c. Insulation system impregnate data sheet as published by supplier. 3360 d. Construction Details including enclosure dimensions, kVA rating, primary & 3361

secondary nominal voltages, voltage taps, BIL, unit weight 3362 e. Basic Performance characteristics including insulation class, temperature rise, 3363

core and coil materials, impedances & audible noise level, unit weight 3364 f. Inrush Current (typical 3 cycle recovery) 3365 g. Short Circuit Current data: Primary (Sym. O/P S/C) & Secondary (L-N/G S/C) 3366 h. Efficiency Data 3367

i. No load and full load losses per NEMA ST20 3368 ii. Linear load Efficiency data @ 1/6 load 3369

iii. Linear load efficiency data @ 1/4, 1/2, 3/4 & full load 3370 iv. Linear Load Efficiency @ 35% loading tested per NEMA TP-2. 3371 v. Efficiency under K7 load profile at 15%, 25%, 50%, 75%, 100% of 3372

nameplate rating. 3373 i. Copy of Factory ISO 9001 documentation describing nonlinear load test 3374

program 3375 i. Meter and CT details including model, accuracy, serial numbers and 3376

calibration information. 3377 j. Copy of Linear & Nonlinear load test report for a representative 75kVA 3378

transformer 3379 k. 25 year Product Warranty Certificate 3380 l. Packaging method for shipment (meeting specification requirements) including 3381

representative picture 3382


m. UL and other applicable agency certifications 3383

B. Description of manufacturer’s factory nonlinear load test program. 3384 a. In light of the significant degradation of transformer performance when feeding 3385

nonlinear load compared to linear load, it is mandatory that the manufacturer 3386 test the transformers under nonlinear load representative of real world load mix. 3387 Transformers that have not been subject to testing under nonlinear load will not 3388 be considered for this project due to the uncertainty related to their real world 3389 performance. 3390

b. Given the lack of a standard for testing transformers under nonlinear load, the 3391 manufacturer must have a nonlinear Load Test Program operating in the 3392 production environment that is audited and documented per quality standard 3393 ISO 9001. 3394

c. The nonlinear load bank shall consist of a phase-neutral loading with a k7 3395 profile, representative of a mix of typical commercial equipment. 3396

d. Meters and CTs shall both be revenue class accurate. CTs shall be operated 3397 within their approved accuracy loading range. Dual meters shall 3398 gather simultaneous primary and secondary energy and harmonic data. Meter 3399 and CT details including model, accuracy, serial numbers and calibration 3400 information. 3401

e. Efficiency: Measurements shall be taken at multiple load levels and plotted to 3402 show compliance with specification and correlation to the designed efficiency 3403 curve. 3404

f. Efficiency shall be determined purely by measurements using method and 3405 instrumentation per NEMA TP-2 Standard. Other methods are not acceptable. 3406

g. Harmonic data including current and Voltage THD at the different load levels 3407 shall be included with the test report. 3408

1.4 PRODUCT LIFE CYCLE STEWARDSHIP 3409

A. Transformer manufacturer shall take back the transformer for component 3410 reuse/recycling at the end of its life. 3411

1.5 DELIVERY, STORAGE AND HANDLING 3412

A. Store and protect products 3413

B. Store in a warm, dry location with uniform temperature. Cover ventilation openings 3414 to keep out dust, water and other foreign material. 3415

1.6 WARRANTY 3416

A. Transformer shall carry a 25-year pro-rated warranty, which shall be standard for the 3417 product line. 3418

1.7 COMMERCIAL PRODUCT 3419

A. Transformer shall be a standard item in the manufacturer’s catalog. 3420

1.8 FACTORY PRODUCT PERFORMANCE VALIDATION 3421

A. At time of order, the customer may request that the project engineer or other 3422 designated customer representative witness the performance testing of one or more 3423 of the transformers on the project at the manufacturer’s facility, along with a 3424 demonstration of integrated metering option if specified. 3425

1.9 ON-SITE PERFORMANCE VALIDATION 3426


A. To insure that the products shipped to the job site meet this specification, provide on-3427 site revenue class accurate efficiency and harmonic measurements of transformers 3428 once installed and operating at customer’s site. Data shall be collected from primary 3429 and secondary sides of the transformer simultaneously on a synchronized cycle by 3430 cycle basis. The use of two discrete meters that are not synchronized is not 3431 acceptable. Sampling shall be of 10% of transformers on the project once installed 3432 and operating, as selected by customer. 3433

B. Demonstrate use of the transformer’s integrated efficiency and power quality meter 3434 where specified. 3435

1.10 INTERNATIONAL STANDARDS ORGANIZATION REGISTRATION OF 3436 MANUFACTURING PLANT 3437

A. Registration to current ISO standard is required. 3438

B. Independent annual audits are conducted. 3439

C. Product shall be manufactured in registered facility 3440

D. ISO 9001:2000 Registered – Quality Management System 3441

E. ISO 14001:2004 Registered – Environmental Management System 3442 a. Transformer manufacturing results in potentially significant emissions of 3443

volatile compounds and other waste. ISO 14001 registration means: 3444 i. That a facility has had an independent environmental impact assessment of 3445

raw material sourcing and all manufacturing processes, 3446 ii. Has implemented an independent annually audited program that 3447

minimizes environmental impact during manufacturing process and 3448 includes a strictly monitored continuous improvement program. 3449

PART 2 SPECIFICATIONS 3450 2.1 TRANSFORMER SPECIFICATION 3451

A. Compatibility: This product must facilitate the ability of the electrical system to 3452 supply a sinusoidal voltage in order to improve the long-term compatibility of the 3453 electrical system with all types of linear and nonlinear connected loads today and in 3454 the future. All national and international standards on harmonics and power quality 3455 set limits on levels of voltage distortion to maintain compatibility. 3456

B. Copper-wound, 3-phase, common core, ventilated, dry-type, isolation transformer 3457 built to NEMA ST20 and relevant NEMA, UL and IEEE standards; 200% rated 3458 neutral; 60Hz rated; Transformers 750 kVA and less, 600 volt primary and less, shall 3459 be U.L. and CSA Listed and bear the label. All terminals, including those for 3460 changing taps, must be readily accessible by removing a front cover plate. Windings 3461 shall be continuous with terminations brazed or welded. 10kV BIL. 3462

C. Insulation System: 3463 a. Shall be NOMEX-based with an Epoxy Co-polymer impregnant for lowest 3464

environmental impact, long term reliability and long life expectancy 3465 b. Class: 220 degrees C 3466 c. Impregnant Properties for low emissions during manufacturing, highest 3467

reliability and life expectancy 3468 d. Epoxy co-polymer 3469 e. VOC: less than 1.65 lbs/gal (low emissions during manufacturing) 3470


f. Water absorption (24hrs @25C): less than 0.05% (superior insulation, longer 3471 life) 3472

g. Chemical Resistance: Must have documented excellent performance rating by 3473 supplier 3474

h. Dielectric Strength: minimum of 3200 volts/mil dry (for superior stress, 3475 overvoltage tolerance) 3476

i. Dissipation Factor: max. 0.02 @25C to reduce aging of insulation, extending 3477 useful life 3478

D. Operating Temperature Rise: 130 degree C in a 40 degree C maximum ambient 3479

E. Noise levels: 3480 a. Per NEMA ST-20 3481 b. Production Test every unit. Data to be available upon request. 3482

F. UL Listed & Labeled K-Rating: K-7 or higher 3483

G. Maximum No Load Losses 3484

c. Transformers are energized 24 hours a day for their entire life, potentially 40 3485 years or more. These losses are incurred whether the transformer is loaded or 3486 not, and cost the user many times the purchase price of the transformer even at 3487 current energy rates. 3488

d. No load losses shall not exceed: 15kVA: 50W, 30kVA: 90W, 45kVA: 120W, 3489 75kVA: 170W, 112.5kVA: 250W, 150kVA: 310W, 225kVA: 430W, 300kVA: 3490 530W, 500kVA: 800W 3491

H. Efficiency at 15% loading 3492 e. Data shows that transformers are typically very lightly loaded for extended 3493

periods of time, therefore to minimize operating cost under real world loading 3494 conditions, efficiency at 1/6 loading shall be maximized. 3495

f. Efficiency at 1/6 load shall meet or exceed: 15kVA: 97.3%, 30kVA: 97.6%, 3496 45kVA: 97.9%, 75kVA: 98.2%, 112.5kVA: 98.4%, 150kVA: 98.5%, 3497 225kVA: 98.6%, 300kVA: 98.7%, 500kVA: 98.8%, 750kVA: 98.9% 3498

I. DOE 10 CFR Part 430 CSL 3 Efficiency requirement, tested per NEMA TP-2: 3499 g. Shall meet or exceed: 15kVA: 97.6%, 30kVA: 98.1%, 45kVA: 98.3%, 3500

75kVA: 98.6%, 112.5kVA: 98.8%, 150kVA: 98.9%, 225kVA: 98.9%, 3501 300kVA: 99.0%, 500kVA: 99.1%, 750kVA: 99.2% 3502

J. Efficiency under k-7 nonlinear load at 50% of nameplate rating: 3503 h. 15kVA: 97.3%, 30kVA: 97.7%, 45kVA: 97.9%, 75kVA: 98.4%, 112.5kVA: 3504

98.7%, 150kVA: 98.8%, 225kVA: 98.8%, 300kVA: 98.8%, 500kVA: 98.9%, 3505 750kVA: 98.9% 3506

K. Voltage Taps: For transformers 30kVA-300kVA, provide two 2-1/2% full capacity 3507 taps above and below nominal primary voltage. For transformers 15kVA and smaller 3508 as well as 500kVA and larger provide one 5% full capacity tap above and below 3509 nominal primary voltage. 3510

L. Impedance: Between 3.5% and 5.8% unless otherwise noted. 3511

M. Enclosure type: NEMA 2, drip-proof [optional NEMA 3R] 3512

N. Integrated Sustained Total Electrical Protection: 3513


i. UL 2P

ndP edition listed for fuseless connection. 3514

j. Single distribution class metal oxide varistor per phase. 3515 k. 100,000 Amp rated 3516 l. Temporary overvoltage withstand: at least 50,000 cycles @ 173% of nominal 3517

voltage, 150 cycles at 200% of nominal voltage 3518 m. End of life condition shall not degrade indoor air quality, or safety hazard. 3519 n. Surge pulses shall be time stamped by the efficiency and power meter (when 3520

provided) 3521

PART 3 EXECUTION 3522 3.1 INSTALLATION 3523

A. Follow all national, state and local codes with respect to transformer installation. 3524

B. Where sound level may be of concern, utilize the services of a recognized and 3525 established Acoustical Consultant to provide the proper installation environment to 3526 minimize noise and vibration. 3527

C. Check for damage and loose connections. 3528

D. Set the transformer plumb and level. 3529

E. Mount transformer on vibration isolation pads suitable for isolating the transformer. 3530

F. Provide Seismic restraints where required. 3531

G. Coordinate all work in this Section with that in other sections. 3532

H. Verify all dimensions in the field. 3533

I. Upon completion of the installation, an infrared scan shall be provided for all bolted 3534 connections. Correct any deficiencies. 3535

J. Adjust transformer secondary voltages to provide the required voltage at the loads. 3536

K. PERFORMANCE VALIDATION: To insure that the products shipped to the job site 3537 meet this specification, provide on-site revenue class accurate efficiency and 3538 harmonic measurements of transformers once installed and operating at customer’s 3539 site. Data shall be collected from primary and secondary sides of the transformer 3540 simultaneously on a synchronized cycle by cycle basis. The use of two discrete 3541 meters that are not synchronized is not acceptable. Sampling shall be of 10% of 3542 transformers on the project once installed and operating, as selected by customer. 3543 Submit a detailed report to the project engineer. 3544

L. Where provided, connect the transformer’s integrated efficiency and power quality 3545 meter to customer’s building management system, network, or other system as 3546 specified. 3547

M. Identify non-compliant products to the engineer and replace at no cost to the 3548 customer. 3549

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