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Controller Sequences and Programming | Return Air Systems

MARCH 2015

J O U R N A LTHE MAGAZINE OF HVAC&R TECHNOLOGY AND APPLICATIONS ASHRAE.ORG

AA S S S S H H H H R R R R A A A A E E E E®

www.info.hotims.com/54426-14

M A R C H 2 0 1 5 a s h r a e . o r g A S H R A E J O U R N A L 3

FEATURES

STANDING COLUMNS

ASHRAE® Journal (ISSN 0001-2491) MISSION STATEMENT | ASHRAE Journal reviews current HVAC&R technology of broad interest through publication of application-oriented articles. ASHRAE Journal’s editorial content ranges from back-to-basics features to reviews of emerging technologies, covering the entire spectrum of professional interest from design and construction practices to commissioning and the service life of HVAC&R environmental systems. PUBLISHED MONTHLY | Copyright 2015 by ASHRAE, 1791 Tullie Circle N.E., Atlanta, GA 30329. Periodicals postage paid at Atlanta, Georgia, and additional mailing offices. LETTERS/MANUSCRIPTS | Letters to the editor and manuscripts for publication should be sent to: Fred Turner, Editor, ASHRAE Journal, [email protected]. SUBSCRIPTIONS | $8 per single copy (includes postage and handling on mail orders). Subscriptions for members $6 per year, included with annual dues, not deductible. Nonmember $79 (includes postage in USA); $79 (includes postage for Canadian); $149 international (includes air mail). Expiration dates vary for both member and nonmember sub scriptions. Payment (U.S. funds) required with all orders. CHANGE OF ADDRESS | Requests must be received at subscription office eight weeks before effective date. Send both old and new addresses for the change. ASHRAE members may submit address changes at www.ashrae.org/address. POSTMASTER | Send form 3579 to: ASHRAE Journal, 1791 Tullie Circle N.E., Atlanta, GA 30329. Canadian Agreement Number 40037127.

ONLINE at ASHRAE.org | Feature articles are available online. Members can access articles at no cost. Nonmembers may purchase articles at www.ashrae.org/bookstore. MICROFILM | This publication is microfilmed by National Archive Publishing Company. For information on cost and issues available, contact NAPC at 800-420-NAPC or www.napubco.com. PUBLICATION DISCLAIMER | ASHRAE has compiled this publication with care, but ASHRAE has not investigated and ASHRAE expressly disclaims any duty to investigate any product, service, process, procedure, design or the like which may be described herein. The appearance of any technical data, editorial material or advertisement in this publication does not constitute endorsement, warranty or guarantee by ASHRAE of any product, service, process, procedure, design or the like. ASHRAE does not warrant that the information in this publication is free of errors and ASHRAE does not necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication and its supplement is assumed by the user.

62

DEPARTMENTS 4 Commentary

6 Industry News

14 Meetings and Shows

88 Products

94 Classified Advertising

96 Advertisers Index

44 ENGINEER’S NOTEBOOK Return Air Systems By Steven T. Taylor, P.E.

48 BUILDING SCIENCES Forty Years of Air Barriers By Joseph W. Lstiburek, Ph.D., P.Eng.

72 DATA CENTERS Are Data Centers Drying Up? By Donald L. Beaty, P.E.; David Quirk, P.E.

26 Energy-Efficient Makeup Air Units By Hugh Crowther, P.Eng.

34 Part Two Radiant Heating and Cooling Systems

By Kwang Woo Kim, Arch.D.; Bjarne W. Olesen, Ph.D.

58 Control Sequences & Controller Programming

By Mark Hydeman, P.E.; Steven T. Taylor, P.E.; Brent Eubanks, P.E.

CONTENTS VOL. 57, NO. 3, MARCH 2015

2015 ASHRAE TECHNOLOGY AWARDS

16 2015 ASHRAE Technology Awards

64 Data Center Economizer Efficiency By Brett Griffin, P.E

78 Energy Efficient Ice Rink By Art Sutherland

7864

48

A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 54

ASHRAE Journal reviews current HVAC&R technology of broad interest through publication of applica-tions-oriented articles. Content ranges from back-to-basics features to reviews of emerging technologies.

COMMENTARY1791 Tullie Circle NEAtlanta, GA 30329-2305Phone: 404-636-8400Fax: 404-321-5478 | www.ashrae.org

PUBLISHER W. Stephen Comstock

EDITORIAL Managing Editor Sarah Foster [email protected]

Associate Editor Rebecca Matyasovski [email protected]

Associate Editor Christopher Weems [email protected]

Associate Editor Jeri Alger [email protected]

Assistant Editor Tani Palefski [email protected]

PUBLISHING SERVICESPublishing Services Manager David Soltis

Production Jayne Jackson Tracy Becker

ADVERTISINGAssociate Publisher, ASHRAE Media Advertising Greg Martin [email protected]

Advertising Production Coordinator Vanessa Johnson [email protected]

CIRCULATIONCirculation Specialist David Soltis [email protected]

ASHRAE OFFICERSPresident Thomas H. Phoenix, P.E.

President-Elect T. David Underwood, P.Eng.

Treasurer Timothy G. Wentz, P.E.

Vice Presidents Darryl K. Boyce, P.Eng.Charles E. Gulledge IIIBjarne W. Olesen, Ph.D.James K. Vallort

Secretary & Executive Vice President Jeff H. Littleton

POLICY GROUP2014 – 15 Chair Publications Committee Michael R. Brambley, Ph.D.

Washington Office [email protected]

Innovative SolutionsIt is a cliché to say that the only con-

stant is change, but “change” is an apt

descriptor of the state of affairs in the

field of building technology and con-

trolled environments. “Evolutionary”

and “dynamic” also work. This issue of

ASHRAE Journal offers ample evidence.

Take the ASHRAE cosponsored AHR

Expo. This issue has a full recap. The

2015 show that took place in January at

Chicago’s McCormick Place claimed the

title for the best-attended AHR Expo

ever with nearly 62,000 total attendees

from 35 countries and more than 11

acres of exhibits. At the ASHRAE con-

ference at the Palmer House downtown,

where ASHRAE standards writing and

technical committees met and engi-

neers from around the world presented

papers and engaged in topical discus-

sions, registration topped 3,000.

WHY THE interest? There have never

been more technology solutions to

choose from, enabling engineers to

improve building and system perfor-

mance. But you need to know what

options there are and under what cir-

cumstances they can best be applied.

That is how the Journal can help.

ASHRAE Journal offers examples of suc-

cessful choices in this issue’s recap of

the 2015 ASHRAE Technology Awards.

Nineteen projects have been singled out

for successful application of innovative

design that incorporate ASHRAE stan-

dards for effective energy management,

indoor air quality, and comfort.

A major criterion of the awards is energy

efficiency. Entries must comply with the

latest ASHRAE Standard 90.1 for new con-

struction and Standard 100 for exist-

ing buildings. Inclusion of one year’s

energy consumption data is strongly

encouraged. If not available, the results of

a nationally recognized computer model-

ing program employed to demonstrate

one year’s energy use is required.

Indoor air quality is another criterion.

Judges look for operating procedures,

source control of contaminants, sys-

tem commissioning and evidence that

design objectives have been achieved.

And they expect detailed descriptions

of compliance with ASHRAE Standard

55 and Standard 62.

ONE ELEMENT all the winning proj-

ects have in common is innovation.

Innovative elements of project designs

must be clearly described—especially

innovative application of technologies,

both old and new, to a particular situa-

tion. New technology or innovation itself

is not sufficient unless the needs of the

facility are truly met. The uniqueness of

the application is the basis of judgment.

There is much to learn through this

issue of ASHRAE Journal. Consider the

report on new products displayed at

AHR Expo and the recap of the ASHRAE

Technology Awards as your roadmap to

the change, evolution and dynamism

that is taking place in the industry today.

W. Stephen Comstock, Publisher


SHOW COVERAGE

FAST FACTSTotal Attendance ................61,674 (registered)**

Visitors ......................................................... 42,344*

Exhibiting Companies ................................2,118**

Percent Increase in Visitor Attendance Over 2012 Chicago Show ...........................................7%

Net Exhibit Space .................................. 486,600**

International Exhibitors ................................593**

Countries Represented ..................................... 35

Educational Sessions .......................................... 52

New Product Presentations ............................... 65

* Chicago record; ** All-time record

Record Breaker in ChicagoSold-Out ExpoSets SeveralAll-Time RecordsCHICAGO—The 2015 AHR Exposhattered several records and claimed the title for the bestattended event ever held in Chicago.

“Chicago is the site of some of our largest Shows and weare thrilled that we set so many new records this year,”said Clay Stevens, president of International ExpositionCompany. “These impressive results also show how vitalAHR Expo is to the industry.

“We’ve had tremendoussupport from the 41 sponsors and endorsing associationsthat participate, as well as from our exhibitors who relyon the Show to introduce new products and meet cus-tomers and prospects from around the world.”

This year’s Show was sold out for some time. It’s

the largest AHR Expo ever with more than 11 acres ofexhibit space.

Stevens attributes this partly

to the economy.“The exhibitor survey that

we did shows that there is even more optimism in theindustry than at last year’s show.”

Nearly 62,000 attended the show, which is an all-timerecord.

Show visitors seemedto agree that the econ-omy is picking up. Russ

Defuria, president of O’Brien Heating and AirConditioning in Drexel Hill, Pa., was attending the

Show for the first time. His company has 12 employeesand did about $2 million in business last year.

Defuria said there is pent-up demand in the residentialHVAC market.

“Last year was our best yearby far. People are loosening up with spending money.”

Bruce Cramer, vice president of Total Building

Environments South inTarpon Springs, Fla., attended his first Show 30 years ago,but had not attended in the past seven years. His energyservices company does energy savings projects for largebuildings. “With the down economy, not many busi-nesses were doing energy sav-ings projects. We had manylean years and were strug-gling to stay alive. Now theeconomy is picking up and it’s starting to get better.”

The next Show is in Orlando, Jan. 25–27, 2016.

Product of the Year CHICAGO—Danfoss’ Turbocor VTT (Variable Twin Turbo) Series Com-pressor is the winner of the 2015 AHR Expo Product of the Year.

The compressor was chosen from the products that won Innovation Awards in 10 industry-related cat-egories. The compressor features the company’s IntraFlow technology to provide high full- and part-load ef-ficiency.

Nearly 62,000 viewed displays of 2,100-plus exhibitors in more than 11 acres of exhibit space.

(L-R) Ken Anderson, Tim Rickards, Patrick Scantlebury, and Sean Giberson hear about Taco’s ECM high efficiency circulators from Steve Thompson.

M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 7

INDUSTRY NEWS

CHICAGO—Ten trends emerged from an online survey of AHR Expo exhibitors and attendees done by ASHRAE Journal. As in 2014, energy efficiency was the top trend from the more than 700 responses.EXHIBITORS1. Energy Efficiency “Energy con-servation, lower power consump-tion of pumps, recirculation.”2. New Technologies “Big trend is visualization of big data.”3. Costs/the Economy “End users looking for very low cost.”4. Sustainability “Green products.”5. Government “We need to get the government and EPA and all

regulatory agencies out of the industry and it will start to grow.”6. Training/Staffing “Lack of quali-fied/competent mechanical design engineers.”7. Environment “Environmental friendly refrigerants and equipment.”8. Fuel “Continuing dominance of natural gas in the heating marketplace.”9. Competition “More manufactur-ers are also starting to buy distri-bution chains to have direct access to the contractor channel.”10. O&M “Lack of owner awareness of overall system life costs with short-life, low-cost products installed.”

TOP TRENDS FOR 2015

ATTENDEES1. Energy Efficiency “I would expect energy efficiency to be a major driver for most markets with rising energy costs.”2. Costs/the Economy “Rising costs for mandated equipment.”3. New Technologies “DOAS units connected directly to terminal units, eliminating large AHUs and large insulated ductwork.”4. Training/Staffing “How do we hire, train, grow, develop, replace, the sales, operations and technical personnel who are retiring?”5. O&M “Contractor’s ability to

effectively start up and maintain newly released high-efficiency products.”6. Government “Regional stan-dards and how it will affect system sales.”7. Refrigerants “Concerns about the transition from R-404A to something else.”8. Competition “Every Tom, Dick and Harry trying to do HVAC.” 9. Environment “Energy saving and environment-friendly products.”10. Sustainability “Minimized energy consumption using heat recovery, net zero. Carbon reduction.”

Rami Al Soleiman (center) shows Matt Kadelback (left) and Daniel Hicks (right) images of the Petra Engineering Industries headquarters and facilities.

The 2015 AHR Expo shattered all-time records as well as records for the Chicago show. AHR Expo is in Chicago every third year and is typically the largest of the Shows.

What’s New at AHRCHICAGO—Here’s a sampling ofnew products shown at the AHR Expo and organized bycategory.

Air DistributionThe DT-ERV from Advantix

Systems is a packaged DOAS that combines liquid desic-cant technology with exhaust air energy recovery. Theunit maximizes ventilation air while reducing energyconsumption which encour-ages optimal air quality and areduced carbon footprint.

ALUAFS.70 UL non-insu-lated aluminum flexible air ducts from AFS are producedfor low and medium pressure heating, cooling, ventilation,exhaust and air condition-ing systems. Made frommulti-layer aluminum and polyester, the ducts have highelasticity and flexibility.

Air King’s Deluxe Quiet

series of range hoods aresuitable for continuous whole house, standard-com-pliant ventilation.

Used with Axial andCentrifugal fans, the new FlowGrid air-inlet grill fromebm-papst reduces ambient noise generated by high-performance technology. The diffuser lessens disturbancesin the fan inflow, minimizes disturbing low frequencytones caused by sound pres-sure in cooling, ventila-tion and air-conditioning systems.

Haier Flexfit ductless systems provide a solutionto mix and match different indoor units to the same out-door unit. This method helps distributors and contractorsreduce the time and cost of inventory management.

The Wireless Zone Control Damper from ALAN

Manufacturing Inc. is controlled by a handheld wireless remote control instead of a thermostat and is capable of controlling up to 32 different dampers in 5% increments.

The TSI-Alnor® EBT731

capture hood from TSI isa modular air balancing instrument designed to meetHVAC TAB and commission-ing requirements.

The all plastic Stratus dif-fuser from American Louveris indistinguishable from


SHOW COVERAGE

(L-R) Kouichi Minamigaito, Keiji Okuyama, and Shingo Mori admire a couple of sheet metal flanges by Mestek Machinery.

Albert Verkuylen gets a close look at the EC medium pres-sure axial fan from ebm-papst.

metal when installed. The diffuser issuitable for commercial and light com-mercial spaces and can be substituted inmost environments where metal units are currently used.

Selkirk’s multi-use models PS and IPS modular, prefabricated double wallventing/chimney/duct systems are com-monly used on appliances such as boil-ers, generators, turbines, kitchen hood grease duct, and coffee roasters.

The LG Art Cool Gallery Multi F indoor units areavailable in 9,000 and 12,000 Btu/h and are outfitted witha frame that allows the cus-tomer to modify and per-sonalize the unit with their own artwork or photography.Features include an inverter variable speed fan, self-cleaning coils, auto opera-tion, and auto restart opera-tion. Cooling is provided via R410A refrigerant and the Chaos Windmode electronically controls fan speeds to create a more natural flow of air whilethe Jet Cool mode operates at high fan speeds for 30 minutes to quickly cool aroom.

Building AutomationControl Solutions’ Babel Buster®

BB2-2010 is a bindable LonWorks® node that functions as a Modbus RTU RS-485master/slave. A large number of data objects provides flexibility in mappingModbus registers to scalar or structured LonWorks net-work variables.

SimplyVAV from KMC Controls is anative BACnet digital VAV controller/ actuator which can perform standaloneor networked VAV control without other software. The unit can be configured viaits companion sensor.

Schneider Electric offers BuildingInsights, a cloud-based system that pro-vides enterprise small buildings real-time visibility and control of all heating, ventilation and air conditioning (HVAC),

lighting and metering devices from anywhere atany time. The system offers facility managers two levelsof control: site-level and cloud-level for both wiredand wireless device control and a custom dashboardview on the cloud-level.

Petra’s air-handling unitcontrol offers a full range of system components frommaster controller and fre-

quency converter to temperature andpressure sensors. Together, the com-ponents can control fans, heating coils,cooling systems and drives for rotary heat exchangers.

Boilers/Water HeatingThe Unilux E-88 series boilers com-

bine the design and construction of pre-vious models with the ability to access the pressure vessel and fireside of theboiler. All units can either be factory assembled or field erected for replace-ment projects.

Marathon International offers the

Baxi Luna Duo-Tec 40 GA combinationcondensing boiler with gas-adaptive technology. The boiler features auto-matic de-aeration, continuous self-calibration, 7:1 modulation range, a two-stage pump, and multiple built-in safety components.

The HeatSponge Sidekick from Boilerroom Equipment retrofits con-ventional hydronic boilers to condens-ing and provides full condensing ofsteam boiler exhaust when a sufficient cold water heat sink exists.

Chillers/Cooling Towers/Chilled WaterSystems

Motivair’s Centricor water chiller, features Turbocor centrifugal compres-sors with magnetic bearings. Features optional free cooling for winter savingsand adiabatic cooling for peak ambient shaving. The PLC controls with remotecommunication and monitoring pro-vide peak performance and security.

The “Service-in-place” water cooled chillers from Tandem Chillers offersimultaneous heating/cooling without reversing the chiller making it easy to domaintenance and service. It is done in place with the rest of the equipment stilloperating.

EcoMESH Adiabatic Systems offersa mesh and water spray system that improves the performance of aircooled chillers, dry coolers and refrig-eration plants while reducing energyconsumption.

Combined Heating, Cooling/ChilledBeams

The Coolerado ERV offers newfunctionality over traditional ERVs. It extends Heat and Mass Exchanger(HMX) performance to all climates to provide cooling, de-humidification,heating and building pressurization.

REK+ from RECUTECH is an alu-minum counterflow air to air heat exchanger with optimized pressure loss,guaranteed maximum tightness and up to 95% efficiency.

The Alfa Laval AC1000 is a true dual circuit brazed plate heat exchanger.Designed for air conditioning, refrig-eration and heat pump applicationsincluding evaporation and condensa-tion, the AC1000 allows the customer

A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 51 0

SHOW COVERAGE


to increase capacity up to 1200kW (341tons), while lowering system cost and boosting efficiency.

Thermalex specializes in manufac-turing difficult heat exchanger shapesused in automotive, commercial/resi-dential, electronic and aerospace heattransfer systems. The aluminum extru-sion products are available in a range

of alloys and coatings.MovinCool’s Climate Pro 18 portable

heat pump provides cooling (14,600Btu/h) and heating (13,700 Btu/h) capac-ity at 115V, 20 amps power. It is self-contained and features an LCD display with on-screen diagnostics as well asautomatic operation during after-hours.

The Hi-Velocity System from Energy

Savings Products is a small duct centralheating and air conditioning system, suitable for new construction, retrofits,historic remodels, recreational proper-ties, and commercial applications.

REHAU offers its radiant heating and cooling system featuring a network ofRAUPEX® O2 Barrier crosslinked poly-ethylene (PEXa) pipes. Used in combi-nation with a downsized air-handling system, the hydronic radiant heatingand cooling system can condition a space efficiently.

The DVM S WATER 20 HP air con-ditioning system from Quietside/Samsung HVAC features a dual inverter compressor with a high efficiency vaporinjection system to ensures rapid cool-ing and heating with minimum energyconsumption. A plate heat exchanger also improves the heat exchange effi-ciency and ensures stable cooling and heating performances.

CoolingEmbraco launches two R-290 com-

pressors for commercial coolers: theFullmotion with variable speed tech-nology and a High Efficiency “On-Off”version. These compressors will support manufacturers’ compliance with EPAand DOE 2017 guidelines.

SSE from Onda is a high efficiency lineof straight tubes dry-expansion evapo-rators. The new design is optimized forR-134a, featuring countercurrent flow, innovative straight tubes pattern andbaffles distribution.

The CCD Cooling Door fromClimaveneta functions as a stand-alone cooling unit for the exhaust air of thesingle rack in small data centers and as a system for managing hot spots in largedata centers, integrating hot and cold aisles or aisle containment structures.

HeatingThe Toyotomi heat convector model

hc-20 features an internal thermostatcontrol that allows the unit to commu-nicate to a zone valve or boiler control-ler. The variable fan speed maximizes operating efficiency.

Baseboarders from Buss General Partner Co. are slip-on baseboardheater covers. The product instantly transforms old functional baseboard

PEACE OF MIND COMES FROM MAKING THE RIGHT CHOICE.

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PROVIDING PEACE OF MIND FOR 75 YEARS.

Contact us to learn more I www.foamglas.com I 1-724-327-6100 I 800-545-5001Protecting Companies and Their People WorldwideTM


SHOW COVERAGE

heaters into modern archi-tectural highlights and fits all makes and models ofhydronic baseboard heaters from the past six decades.

Fujitsu General America, Inc. introduces theAirstageVR-II VRF heat recovery system that allowsfor simultaneous heat-ing and cooling operation.Energy efficiency doubles when the system provides

50% cooling and 50% heatingsimultaneously.

SunTherm’s ModularHydronic Furnaces, series model MMVE, offers 4-waymultiposition application and provides cooling airflow.All models offer variable speed, high efficiency, ECMmotors and can include optional factory-installed cir-culating pumps.

The InSpire wall panel fromATAS International is a solar air heating and drying systemthat is mounted on a build-ing’s outer wall. Solar-heatedair at the surface of the panel is drawn through perfora-tions where it rises between the two walls and enters thebuilding’s central ventilation system or supply fan.

Humidification/Dehumidification

DriSteem offers a line of

water pre-treatment andreverse-osmosis systems. These systems delivermineral-free water for a wide variety of applica-tions and processes beyond humidification. The systemscan integrate with building automation systems using acontroller.

Indoor Air QualityThe Bi-Polar 2400 from

Air Oasis is a filterless cold plasma air purifier the sizeof a smart phone. The unit installs in almost any system,ducted or not and is water resistant.

The Wi-Fi enabled FILTERSCAN Air FilterMonitor and Notification System from CleanAlertsends notifications via local, text and e-mail alerts when afilter needs servicing by mea-suring differential pressure

changes in a HVAC system.C Cloud Filter’s V-Bank

filters are designed for usein commercial, industrial, manufacturing and medicalfacilities. Filters are available from MERV 13-16 and featurelow air pressure drop and long filter life.

The GeneralAire PCO2450 VectorFlo photocatalytic

Becky Trujillo, Trane Commercial, shows Clive Broadbent the Sintesis air-cooled liquid chiller.

Haixia Li poses with a brass and steel brazed statue of Joe Harris, founder of Harris Products Group.


M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J O U R N A L 1 3

SHOW COVERAGE

See Products, Page 90


oxidation air purifier fea-tures a patented semicon-ductor designed to deliver ahigh-performance kill rate. It reduces germs, bacteria, andviruses in your home.

LightingThe SwitchSense™ bat-

tery backup LED driver from Wireless Environmentworks in conjunction with an AC LED driver to add abattery backup to new or existing LED luminairesor lamps. The patented technology eliminates theneed to wire an unswitched connection to the control-ling switch. The embedded switch sensing capabilityallows a luminaire or lamp to be installed as a retrofit,making use of existing wir-ing to add power outage

lighting functionality to theluminaire.

Philips offers the LUXEON3535 HV mid-power surface-mount-device (SMD) LEDthat comes in both 24V and 48V configurations. The highvoltage and lower current lead to an efficient driverand allows for a reduction in LED count with better lightextraction. The LEDs are available in a color tempera-ture range of 2700–5000K.

Motors, Drives, CompressorsDomel’s EC motors use

ferrite magnets and feature low noise, low weight, and acompact design. The motor design protects it from dustand allows it to operate in a wide range of temperatures.

Browning introduces an expanded range of sizes for

its self-tensioning Tenso-setmotor base. The expanded product range for the energy-saving Tenso-set base will include up to NEMA 447 andequivalent IEC motor frame sizes.

Designed for the HVAC industry, TriangleManufacturing’s direct drive motor mounts feature noisesuppression, knock down shipping and customizability.The motors’ arms and bands are shipped unassembledand can reduce needed ware-house space and shippingcosts.

The CSVW2 compact screwcompressors from BITZER are for use in water cooledchillers for systems with low saturation dischargetemperatures and which are equipped with new

permanent magnet motors.These motors are more efficient than conventionalmotor technologies at lower speeds and loading ranges.

PlumbingAquatechnik Group

manufactures white pipesand fittings of PP-R 80 SUPER for polyfusion weld-ing. They are suitable for all plant-engineering systems,particularly for the transport of potable and non-potable,warm and cold fluids, with a working temperature up to200°F (93°C).

Niccons Italy offers line-setprotection, made of rigid PVC without lead, for air-condi-tioning installations. Available in several measurements,the system allows a total and



MEETINGS AND SHOWS FULL CALENDAR: WWW.ASHRAE.ORG/CALENDAR

CALLS FOR PAPERSASHRAE JOURNAL ASHRAE Journal publishes applications-oriented articles that are 3,000 or fewer words. Graphics are encouraged. All ar-ticles are subject to editorial and peer reviews and cannot have been pub-lished previously. Authors should sub-mit abstracts before sending articles to [email protected].

SCIENCE AND TECHNOLOGY FOR THE BUILT ENVIRONMENTASHRAE’s Science and Technology for the Built Environment (previously known as HVAC&R Research Journal) seeks papers on origi-nal, completed research not previously published. Papers must discuss how the re-search contributes to technology. Papers should be about 6,000 words. Abstracts and papers should be submitted on Manuscript Central at www.ashrae.org. For more infor-mation, contact Reinhard Radermacher, Ph.D., Editor, at [email protected].

ASHRAE CONFERENCE PAPERS ASHRAE seeks papers for presentation at Society Conferences. For the 2016 Winter Conference in Orlando, Fla., conference paper abstracts are due March 23, 2015. For more information, contact 678-539-1137 or [email protected].

MARCHHVACR & Mechanical Conference for Educa-tion Professionals, March 9 – 11, Baltimore. En-dorsed by ASHRAE. Contact Warren Lupson at 703-600-0308, [email protected], or www.instructorworkshop.org.

IAQA Annual Meeting and Indoor Environment and Energy Expo, March 16 – 18, Grapevine, Texas. Contact the Indoor Air Quality Association at 844-802-4103, [email protected], or www.iaqa.org.

AEI Conference, March 24 – 27, Milwaukee. Con-tact Elaine V. Watson, American Society of Civil En-gineers, at [email protected] or www.asce.org/aeiconference2015.

APRILNEBB Annual Conference, April 16 – 18, Honolulu. Contact the National Environmental Balancing Bureau at 301-977-3698 or www.nebb.org/events.

MAYLightfair International, May 3 – 7, New York. Con-tact organizers at 404-220-2220, [email protected], or www.lightfair.com.

EE Global 2015, May 12 – 13, Washington D.C. Con-tact Becca Rohrer, Events Associate as Alliance to Save Energy at 202-0530-2206, [email protected], or www.eeglobalforum.org.

AIA Convention 2015, May 14 – 16, Atlanta. Con-tact the American Institute of Architects at 800-242-3837, [email protected], or www.aia.org/convention.

AIHce 2015, May 30 – June 4, Salt Lake City. Contact Lindsay Padilla at the American Industrial Hygiene Association at 703-846-0754, [email protected], or www.aihce2015.org.

JUNEASHRAE Annual Conference, June 27 – July 1, Atlanta. Contact ASHRAE at 800-527-4723 or [email protected].

Every Building Conference and Expo, June 28 – 30, Los Angeles. Contact the Building Owners and Managers Association at 202-326-6331, [email protected], or www.bomaconvention.org.

JULY Solar 2015, July 28 – 30, State College, Pa. Contact 303-443-3130, [email protected], or http://solar2015.ases.org.

AUGUST NAFA Annual Convention, Aug. 27 – 29. Key West, Fla. Contact the National Air Filtration Associa-tion at 757-313-7400, [email protected], or www.nafahq.org.

SEPTEMBERSMACNA Annual Convention, Sept. 27 – 30, Colo-rado Springs, Colorado. Contact the Sheet Metal and Air Conditioning Contractors’ Association at 703-803-2980, [email protected], or www.smacna.org.

RETA Conference, Sept. 29 – Oct. 2, Milwaukee. Contact the Refrigeration Engineers and Techni-cians Association at 831-455-8783, [email protected], or www.reta.com.

World Energy Engineering Congress, Sept. 30 – Oct. 2, Orlando, Fla. Contact the Association of

Energy Engineers at 770-447-5083, [email protected], or www.energycongress.com.

OCTOBERIFMA’s World Workplace, Oct. 7 – 9, Denver. Con-tact the International Facility Management Asso-ciation at 713-623-4362, [email protected], or www.ifma.org.

AHR Expo-Mexico, Oct. 20 – 22, Guadalajara, Mex-ico. Contact the International Exposition Compa-ny at 203-221-9232, [email protected], or www.ahrexpomexico.com.

CTBUH 2015, Oct. 26 – 30, New York. Contact the Council on Tall Buildings and Urban Habitat at 312-567-3487, [email protected], or www.ctbuh2015.com.

NOVEMBERGreenbuild International Conference & Expo, Nov. 18 – 20, Washington, D.C. Contact organizers at 866.815.9824, [email protected], or www.greenbuildexpo.com.

2016JULY2016 Purdue Compressor/Refrigeration and Air Conditioning and High Performance Buildings Conferences and Short Courses, July 11 – 14, West Lafayette, Ind. Contact Kim Stockment, Conference Coordinator at 765-494-6078, [email protected], or http://tinyurl.com/Purdue2016.

OCTOBERASPE Convention and Exposition, Oct. 27 – Nov. 4, Phoenix. Contact the American Society of Plumb-ing Engineers at 847-296-0002, [email protected], or www.aspe.org.

OUTSIDE NORTH AMERICAMARCHISH 2015, March 10 – 14, Frankfurt, Germany. Contact 49 69 75 75 0 or www.ish.messefrankfurt.com.

APRILChina Refrigeration, April 8 – 10, Shanghai. Con-tact organizers at [email protected] or www.cr-expo.com.

International Conference on Fan Noise, Tech-nology and Numerical Methods (FAN 2015), April 15 – 17, Lyon, France. Contact www.fan2015.org.

CIAR 2015, April 28 – 30, Madrid. Contact [email protected] or www.ciar2015.org.

MAYMostra Convegno Expocomfort Saudi, May 4 – 6, Riyadh, Saudi Arabia. Contact Reed Exhibitions at 39 02 4351701, fax 39 02 3314348, [email protected] or www.mcexpocomfort.it.

Advanced HVAC and Natural Gas Technolo-gies 2015, May 6 – 9, Riga, Latvia. Endorsed by ASHRAE. Contact Agnese Lickrastina, Riga Techni-cal University at [email protected] or www.hvacriga2015.eu.

2015 International Conference on Energy and En-vironment in Ships, May 22 – 24, Athens, Greece. Contact ASHRAE at 800-527-4723, [email protected], or www.ashrae.org/Ships2015.

JULYISHVAC-COBEE 2015, July 12 – 15, Tianjin, China. Endorsed by ASHRAE. Contact organizers at [email protected] or http://www.cobee.org.

AUGUSTBangkok RHVAC, Aug. 14 – 16, Bangkok. Contact the Office of Agriculture and Industrial Business Devel-opment at 66 (0) 2507 8374-8, [email protected], or www.bangkok-rhvac.com.

IIR International Congress of Refrigeration, Aug. 16 – 22, Yokohama, Japan. Endorsed by ASHRAE. Contact 81 3 3219 3541, [email protected], or www.icr2015.org.

SEPTEMBERMostra Convegno Expocomfort Asia, Sept. 2 – 4, Singapore. Contact Reed Expositions Singapore at 65 6780 4671, fax 65 6588 3832, [email protected] or www.mcexpocomfort-asia.com.

OCTOBER8th International Cold Climate HVAC Confer-ence, Oct. 20 – 23, Dalian, China. Endorsed by ASHRAE. Contact organizers at 86 411 84709612, [email protected], or www.coldclimate2015.org.

11th International Conference on Industrial Ventilation, Oct. 26 – 28, Shanghai. Endorsed by ASHRAE. Contact 86 21 65984243, [email protected], or www.ventilation2015.org.

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TechnologyAwards

ASHRAE Technology Awards recognize outstanding achievements by members who

have successfully applied innovative building design in the areas of occupant comfort,

indoor air quality and energy conservation. Their designs incorporate ASHRAE standards

for effective energy management and IAQ. Performance is proven through one year’s

actual, verifiable operating data.

This year’s awards recognize buildings designed for a range of occupant types and uses

including penguins, patients, skaters, students, government employees and water testers.

The following describes projects from the 2015 ASHRAE Technology Awards winners and

honorable mentions. Articles about these projects will be published in future issues of

ASHRAE Journal and High Performing Buildings magazine.

2015 ASHRAE


2015 ASHRAE TECHNOLOGY AWARD CASE STUDIES

FIRST PLACEBENJAMIN FRANK GOZART, ASSOCIATE MEMBER ASHRAEFEDERAL CENTER SOUTH – BUILDING 12021, SEATTLE

Federal Center South used an

integrated design approach that

focused on energy conservation

measures vs. expensive on-site

energy generation strategies.

Several innovative technologies

include: passive chilled sails; ther-

mal storage using phase change

material; a 100% outside air venti-

lation system with heat recovery of

exhaust serving a raised floor ven-

tilation air distribution system;

and heat recovery chillers tied to

a high efficiency low temperature

heating/high temperature cooling

hydronic system.

FIRST PLACEROGER (JUI-CHEN) CHANG, P.E., BEMP, MEMBER ASHRAEWAYNE N. ASPINALL FEDERAL BUILDING AND U.S. COURTHOUSE

FIRST PLACEBRIAN A. HAUGK, P.E., MEMBER ASHRAEVALLEY VIEW MIDDLE SCHOOL

The project converted a 1918

landmark into one of the most

energy efficient, sustainable

historic buildings in the coun-

try. To meet aggressive perfor-

mance goals, including energy

independence and energy effi-

ciency, the design included: a

roof canopy-mounted 123 kW

PV array; addition of spray foam

and rigid insulation to building

shell; storm windows with solar

control film to reduce demand

on HVAC; and VRF heating and

cooling systems tied to a 32-well

geoexchange loop.

A water-to-water heat pump

(WWHP) allowed the design team

to use displacement ventilation,

which requires very tight dis-

charge air temperature control,

to maintain occupant comfort

only achievable with a WWHP

system. This project was one of

the first to use this technology in

the region and fully integrates

the factory controls with the EMS

system.

PHOTO: KEVIN G. REEVES, PHOTOGRAPHER, COURTESY OF WESTLAKE REED LESKOSKY

PHOTO: BEN BENSCHNEIDER


FIRST PLACEMATTHEW WILLIAM LONGSINE, P.E., ASSOCIATE MEMBER ASHRAETACOMA CENTER FOR URBAN WATERS, ZEELAND, MICH.

The 51,000 square foot lab

facility functions as a shared

research facility for the City

of Tacoma, the University of

Washington and Puget Sound

Partnership. It focuses on receiv-

ing and analyzing water samples

from the waterways of Tacoma

and surrounding areas.

Design features include heat

recovery, energy efficient light-

ing, daylighting, natural ventila-

tion, radiant floors, low-e glass

and exterior operable shading,

VAV low flow fume hoods, and

rainwater harvesting.

FIRST PLACEKATERI HÉON,ING., ASSOCIATE MEMBER ASHRAECENTRE CIVIQUE DE DOLLARD-DES-ORMEAUX

An energy-efficiency program

was developed to increase the

performance of the refrigeration

system for three indoor rinks

and then to recover the energy

rejected from the center com-

pressors to heat the building.

The design team chose a system

that featured a direct carbon

dioxide heating and regenera-

tion of a dehumidifier desiccant

wheel, which is the first time this

system has been used in a rink in

North America. The system also

is the first to use carbon dioxide

in a multi-rink complex.

FIRST PLACEMARK STAVIG, MEMBER ASHRAEPEACE ISLAND MEDICAL CENTER

Island resources are limited,

which made sustainable choices

vital and simple design neces-

sary. The mechanical system was

designed to use only electric-

ity, the only available energy

source on the island. The project

employs numerous energy effi-

ciency measures and achieves an

average EUI of 87.7 kBtu/square

foot per year.

A conscious effort was made to

reduce cooling demand resulting

from building envelope and plug

loads.

PHOTO: BEN BENSCHNEIDER

1 8 A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 5





FIRST PLACEWILLIAM C. WEINAUG JR., P.E., MEMBER ASHRAEANTARCTICA: EMPIRE OF THE PENGUIN

When creating a 32°F space

in hot and humid Orlando, the

efficiency of the systems and

envelope is crucial. The facility

is designed to minimize energy

use while providing a habitat for

penguins to thrive.

In regard to thermal comfort,

the criteria were driven by birds’

comfort instead of humans.

Human comfort was measured

by how well odors were con-

trolled. Designers also had to

protect the birds from mold and

fungi not common to their native

environment.

FIRST PLACEARTHUR GILBERT SUTHERLAND, MEMBER ASHRAEWESTHILLS RECREATION CENTER

The mechanical system for the

three ice surfaces are integrated

into the building HVAC system

to the extent that no fossil fuels

are used for the facility other

than in the kitchen. The outdoor

rink offers an interesting energy

balance opportunity in winter

by providing additional rejected

energy during the heating sea-

son. Even with the extensive

use of energy, only 40% of waste

energy is required within the

complex. The remaining 60%

is pumped to a nearby housing

development.

FIRST PLACEJASON TROY LAROSH, P.E., MEMBER ASHRAEJANESVILLE ICE ARENA ADDITION AND RENOVATION

The project included renova-

tion of the existing 26,000 square

foot arena with the addition of

2,000 square feet that included

new locker rooms, an ice resur-

facing melt pit and resurfacing

equipment storage area.

The original ice refrigeration

system, installed in 1964, was a

direct refrigeration system that

used R-22 refrigerant circulated

in piping embedded in the floor.

The new system incorporates a

pond loop geothermal system

to handle the high refrigeration

needs of the arena.






SECOND PLACEPERRY HAUSMAN, MEMBER ASHRAE, CORPORATION HALLFor this mixed use building, sustainable features include a green roof, lowflow plumbing fixtures, high-efficiency mechanical units, low consumption LED lighting, lighttubes, solar thermal energy, geo-thermal silent heat through the radiant floor and a non-idling demand response snowmelt system.

STANLEY KATZ, ASSOCIATE MEMBER ASHRAE, COMPLEX SOUTHWEST ONEThe addition of a new radiology clinic at a residential complex challenged the design team to reduce the impact of the clinic on the residential complex dur-ing and post construction. The design team used heat recovery and a new chiller without a cooling tower.

ERIC WILLIAM SHAW, MEMBER ASHRAE, UPPER THAMES RIVER CONSERVATION AUTHORITYThe design of this administrative building combines innovative technologies and good practice, achiev-ing a 71% reduction in energy use over the regu-lated requirements for energy efficient buildings (MNECB). Compared to ASHRAE/IES Standard 90.1-2007, the estimated energy savings was 56%.

Corporation Hall

ComplexSouthwest One

AARON ROBERT SMITH, P.ENG., MEMBER ASHRAE, 100 VENTURE RUN100 Venture Run is a three-story office building in Nova Scotia that achieved LEED Canada Gold Core and Shell 2009; the first LEED Gold Core and Shell project in the province. This building is to be used as a template for future buildings at the site so building performance was analyzed early in the design process and a rigorous commissioning and measurement and verification process took place.

HONORABLE MENTION

JACQUES LAGACÉ, ING, MEMBER ASHRAE, COMMISSION DE LA CONSTRUCTIONDU QUEBECThis office building design began with a thoroughanalysis of the data center to capitalize on its opera-tion and needs so as to effectively adapt the buildingservices to them. The design reclaimed energy pro-duced by the data center and used it efficiently.

DONALD J. MCLAUCHLAN, P.E., MEMBER ASHRAE, SUN LIFE ASSURANCE COM-PANY 29 NORTH WACKER RENOVATION PROJECTAn ASHRAE Level II audit identified 10 energy con-servation measures for this existing building such asa steam-to-water conversion, a chilled water plantoverhaul, redesign of the perimeter HVAC system toincorporate active chilled beams, a new interior VAVsystem and refurbishment of AHUs.

JEAN-PHILIPPE MORIN, ASSOCIATE MEMBER ASHRAE, CSSS POINTE-DE-L’ILEAn ASHRAE Level III audit identified energy-effi-ciency measures for this existing building such as air-to-air heat-recovery systems; geothermal heating sys-tem; condensing boilers retrofit; kitchen hood systemvariable flow conversion; and condensing hot-waterheaters retrofit.

BRETT MASON GRIFFIN, MEMBER ASHRAE, DIGITAL REALTY DATA CAMPUSThe heart of the mechanical system for this data cam-pus is the chiller plant. Due to aggressive speed tomarket and flexibility requirements, the chiller plantwas designed to be modular and scalable to allow forthe plant to be stick built onsite or pre-built offsite.

CHARLES E. GULLEDGE, III, MEMBER ASHRAE, CATERPILLAR ASSEMBLY PLANTThe Caterpillar Assembly Plant is a new, state-of-the-art, heavy manufacturing facility in Georgia. The proj-ect was completed via a design-build delivery modelon a greenfield site.

TERRY G. AUTRY, P.E., MEMBER ASHRAE, NCAR-WYOMING SUPERCOMPUTING CENTERTo achieve high levels of cooling system efficiency,RMH engineers harnessed the cool, dry climate ofCheyenne by using evaporative cooling towers to effi-ciently deliver 65ºF chilled water directly to NCAR’sliquid-cooled supercomputers for 98.6% of the year.That same 65ºF chilled water is moved into fan wallcooling coils for the air-cooled computers.


TECHNICAL FEATURE

Hugh Crowther, P. Eng., is a consultant to Price Industries. He is past chair of ASHRAE Standards Committee.

BY HUGH CROWTHER, P.ENG., MEMBER ASHRAE

Energy-EfficientMakeup Air Units Air Units AirUnless you live in paradise, delivering makeup delivering makeup delivering air to most buildings is expensive.Table 1 shows the amount of work of work of it takes to heat and cool air (based on Chicagoconditions) for a standard rooftop unit (a unit that recirculates air with typical airconditioning loads)conditioning loads)conditioning and a makeup air (MUA) unit. Note the standard unit conditionsrepresent 400 cfm/ton (53.68 L/[s·kW]) with 80°F dry bulb/67°F dry bulb/67°F dry wet bulb (26.7°C drybulb/19.4°C wet bulb) return air conditions. It can be seen that a MUA unit MUA unit MUA requiresmore than twice the cooling and cooling and cooling five times the heating work heating work heating as a standard unit.

For many HVAC solutions a dedicated outdoor air

system (DOAS) is required such as variable refriger-

ant flow systems (VRF), ground source heat pumps

(GSHP), and chilled beams (Figure 1). Many process

applications (labs, industrial processes, garages, etc.)

also require makeup air (MUA) systems. All these

applications require some form of make up air unit

that can move and filter outdoor air as well as heat

and cool (depending on location and application).

Since these units consume significant energy in most

applications, a discussion on how to improve their

efficiency is warranted.

A basic MUA unit has to meet certain minimum per-

formance requirements:

• 80% efficient (indirect fired) gas heat1 (assuming a

gas heat unit);

• 10 EER (Energy Efficiency Ratio)2 if DX cooling is

required;

• Fan performance is generally marginalized but is

accounted in the unit EER requirement (assuming there

is cooling); and

• Basic wall construction called out in the product

specification. A basic unit is typically single wall, 0.5 to 1

in. (13 to 25 mm) fiberglass insulation.

To move beyond a basic unit, four areas of improve-

ment will be considered: gas heat, DX cooling, fan per-

formance, and casing performance (Figure 2). The energy

usage calculations are based on a 10,000 cfm (4700 L/s)

MUA unit in Chicago. The cost3 of gas is $0.79/therm

and electricity is $0.10 kWh. The carbon dioxide (CO2)

equivalent conversion4 for natural gas is 0.510 CO2e

lb/kWh (0.232 kg/kWh) and for electricity is 1.670 CO2e


TECHNICAL FEATURE

lb/kWh (0.758 kg/kWh). Calculations are based on 24/7

operation.

Improving Gas HeatingTo improve gas heating the efficiency needs to be

increased. Gas heat efficiency is heat added to the air-

stream/heat released in the combustion of the fuel. By

code, MUA units need to have 80% minimum efficiency.

Technology is now available to raise the heating effi-

ciency of MUA units to 90% or greater (Photo 1). However,

this results in acidic condensation of water vapor in the

combustion gas. As well, the increased heat exchanger

surface area increases the air pressure drop by approxi-

mately 0.10 in. w.c. (25 Pa), which will increase fan work.

Condensing boilers have been gaining acceptance for

some time now but they are located in a boiler room

with a floor drain. A condensing gas furnace in a roof

mounted MUA unit requires careful planning both by

the design engineer and the installing contractor, par-

ticularly if the ambient falls below freezing. It is recom-

mended that the condensate be routed down through

the roof curb to a drain within the building. If the con-

densate must be exposed to freezing conditions, heating

tracing should be applied. Local codes may also require

pH neutralizing kits.

Table 2 compares the natural gas savings between an

80% efficient and 90% efficient furnace. The savings in

natural gas and operating cost are around 11%. In this

application it is about a two-year payback.

Improving DX CoolingMinimum efficiencies for package rooftop units

in a recirculation application are provided in

ASHRAE Standard 90.1. The efficiencies are based

on AHRI Standard 340/360 that assumes 80°F/67°F

(26.7°C/19.4°C) dry bulb/wet bulb entering air condi-

tions. Since a MUA unit sees more demanding loads,

the efficiencies listed are not generally obtained. Since

the airflow rate per unit of cooling is typically half in

a MUA unit (i.e., 200 cfm/ton [26.84 L/s·kW]) versus a

recirculating unit (i.e., 400 cfm/ton [53.68 L/s·kW]), it

is often not possible to operate a MUA unit at the condi-

tions stated in AHRI Standard 340/360. The end result is

that cooling efficiency targets for MUA units are not well

established and are left up to the designer.

TABLE 1 MUA energy requirements.

DESIGN CONDITIONS

DRY BULB/WET BULB °F Δ ENTHALPY

(BTU/H · CFM)COOLING WORK

(W/CFM)HEATING WORK (BTU/H · CFM)

STANDARD UN IT

80/67 to 57.6/57 30 3.0

54.1 to 70 (20% OA) 16 19

MUA UN IT90/75 to 55/54.5 70 7.0

–1.5 to 70 78 97

FIGURE 1 Typical make-up air system.

PHOTO 1 Ninety percent gas furnace.

FIGURE 2 High performance MUA unit.

Gas HeatFans

Cabinetry

DX Cooling


Energy efficiency ratio (EER) is the total cooling

capacity (Btu/h)/electrical power for supply air fans,

condenser fans, and compressors (W). Since supply fan

work will be discussed separately, let’s assume an EER of

10 for just the compressors and condenser fans at MUA

conditions for a basic unit and an EER of 11 for a high

efficiency unit. As well, it is assumed that dehumidifica-

tion is required and thus the air will be cooled to 55°F

(12.8°C). (where neutral air temperatures are required,

DX cooled makeup air units often include hot gas reheat,

which uses waste heat to warm the air).

Table 3 shows the savings are around 9% with a four-

year payback. Location has a lot to do with the payback.

Moving the location from Chicago to Miami would

greatly improve the payback for the improved cooling

efficiency.

Supply Fan SavingsIndirect fired MUA units must have the fans in a

blow-through position relative to the furnaces. This is

a safety issue. The most cost-effective fans are forward-

curved scrolled fans, but they discharge into an open

plenum, which is not an ideal application. There is little

static pressure regain without discharge ductwork. For

scrolled fans, this loss is usually accounted for by adjust-

ing the total static pressure (TSP) for the system loss

or by using fan curves that are based on actual testing

with a scrolled fan in a blow-through arrangement. In

this case, the TSP was increased by 0.2 in. w.c. (50 Pa)

to account for the system effect and will impact the fan

efficiency.

Optional fan arrangements include airfoil scrolled

fans, and belt and direct drive plenum fans. Belt drive

units have a drive loss around 2% while direct drive fans

will require a VFD that will introduce a drive loss around

2%. From an energy point of view for constant volume

applications, direct (VFD) and belt drive losses are about

equal.

Table 4 summarizes the impact of different fan choices

using 3 in. w.c. (750 Pa) total static pressure for a 10,000

cfm (4700 L/s) unit operating 24/7.

The energy savings from worst to best is 28% and has

a less than two-year payback. The direct drive plenum

fans also offer reduced maintenance (no belts) and the

ability to vary the supply airflow for further energy sav-

ings (depending on the building application).

Casing SavingsCasing energy losses take two forms; thermal losses

through the cabinet wall and exfiltration (air leakage on

the positive pressure side of the fan). Exfiltration adds

a secondary loss in that the supply fan airflow rate will

likely be increased (through the testing and balancing

process) to deliver the correct airflow to the point of use

thus increasing the fan work and likely the heating and

cooling work.

TABLE 3 DX cooling savings.

TEMPERATURE RANGE

(°F)

NUMBER OF OCCURRENCES

(HR)

COOLING LOAD

(BTU/H)

10 EER 11 EER

ELECTRICITY USAGE

(W)

COST($)

ELECTRICITY USAGE

(W)

COST($)

90 to 100 48 1,288,800 128,880 330 117,164 299

80 to 90 466 996,300 99,630 2,207 90,572 2,007

70 to 80 1,234 661,050 66,105 4,050 60,095 3,682

60 to 70 1,480 248,400 24,840 1,659 22,582 1,508

Totals 3,228 8,247 7,497

TABLE 4 Fan savings.

FAN TYPEAIRFLOW

(CFM)FAN WORK

(W)ANNUAL WORK

(KWH)ANNUAL COST

($)

Twin FC Scrolled Fans 10,000 6,833 59,860 5,986

Twin AF Scrolled Fans 10,000 5,655 49,535 4,953

Belt Drive Plenum Fan 10,000 5,252 46,006 4,601

Direct Drive Plenum Fan 10,000 4,939 43,261 4,326

TABLE 2 Gas heat savings.

TEMPERATURE RANGE

(°F)

NUMBER OF OCCURRENCES

(HR)

HEAT LOAD (BTU/H)

80% EFFIC I ENCY 90% EFFIC I ENCY

GAS USAGE(CFH)

COST ($)

GAS USAGE(CFH)

COST($)

65 to 75 1,252 108,500 132 638 117 567

55 to 65 1,472 325,500 397 2,230 353 1,982

45 to 55 1,204 542,500 662 3,147 588 2,797

35 to 45 1,380 759,500 926 5,172 823 4,597

25 to 35 1,396 976,500 1,191 6,506 1059 5,783

15 to 25 648 1,193,500 1,456 3,731 1293 3,316

5 to 15 202 1,410,500 1,720 1,359 1529 1,208

–5 to 5 88 1,627,500 1,984 683 1765 607

–15 to (–5) 28 895,125 1,092 241 970 215

Totals 7,642 23,706 21,072

TECHNICAL FEATURE


assumed to be 4% while for the high performance cabi-

net the leakage rate is assumed to be 1%.5

Table 5 shows that a high performance cabinet can offer

a 77% savings and that cabinet leakage is three to five

times more important than thermal loss. The savings are

comparable to DX cooling improvement for this climate.

Summary and ConclusionsTable 6 summarizes the savings that are possible by

using equipment that performs beyond the minimum

requirements. The energy savings for all improve-

ments are 14%, and the cost savings are around $6,000/

yr. This works out to around $0.60/supply air cfm per

year ($0.29/supply air L/s per year). Assuming a 20%

premium for the high-performance unit, the payback is

around two years. Smaller units will have a higher pre-

mium and hence a longer payback. Since a MUA unit is a

high energy consuming device, investing in greater than

minimum efficiency performance is generally a good

design goal and offers a better return on investment

than upgrading other components in the HVAC system.

Table 6 also shows the CO2 equivalent savings based on

factors from ASHRAE Standard 189.1. The CO2 reduction

is almost 110,000 lbs/yr.

Not all the reviewed improvements are equal in sav-

ings and some are location dependent. Fan improve-

ment savings are universal in terms of location. Any

improvement to the fan system will deliver good

results as long as the unit is running. Cabinet perfor-

mance is also fairly universal. The bulk of the energy

penalty comes from leakage so the weather conditions

at point of use are less of an influence. Cold weather

climates benefit more from better thermal perfor-

mance than hot climates (the temperature differences

are larger).

Cooling and heating savings are heavily dependent on

location. Miami will enjoy a fast payback on improved

cooling efficiency while Winnipeg will see the same for

the high-performance furnace. In this example, the

improved cooling in Chicago has the longest payback

due to the low BIN hours of operation. In Miami, cooling

would be one of the most important improvements. The

designer should take this into account when specify-

ing equipment. A quick review of the BIN hours for the

TABLE 5 Casing savings.

BASIC CAB INET H IGH PERFORMANCE CAB INET

CAB INET HEAT LOSS INFI LTRATION CAB INET HEAT LOSS INFI LTRATION

TEMPERATURE RANGE DB

(°F)

NUMBER OF OCCURANCES

(HR)

LOAD (BTU/H)

COST ($)

HEAT LOAD (BTU/H)

COST ($)

HEAT LOAD (BTU/H)

COST ($)

HEAT LOAD (BTU/H)

COST($)

90 to 100 48 6192 1 32,832 9 953 0 8,208 2

80 to 90 466 3,096 6 21,132 45 477 1 5,283 11

70 to 80 1234 629 4 7,722 47 97 1 1,931 12

60 to 70 1480 1,935 14 8,680 65 298 2 2,170 16

50 to 60 1187 3,870 22 17,360 99 595 3 4,340 25

40 to 50 1058 5,805 29 26,040 131 893 5 6,510 33

30 to 40 1739 7,740 65 34,720 290 1,191 10 8,680 72

20 to 30 896 9,675 41 43,400 185 1,488 6 10,850 46

10 to 20 461 11,610 25 52,080 113 1,786 4 13,020 28

0 to 10 132 13,545 9 60,760 38 2,084 1 15,190 10

–10 to 0 59 15,480 4 69,440 20 2,382 1 17,360 5

Totals 8760 221 1,041 34 260

A basic unit casing in a MUA

unit is typically single-wall steel

with 0.5 in. to 1 in. (12 to 25 mm)

fiberglass insulation glued to it.

The R value will be around 2. A

high performance casing will be

2 in. (51 mm) injected foam con-

struction with an R value around

R-13. The supply air pressure will

cause deflection in the cabinet

walls. Deflection creates open-

ings that lead to air infiltra-

tion or exfiltration. Single-wall

construction units can have

significant deflection and thus

leakage.* Injected foam cabinets

are very rigid and can have a

deflection of less than L/240. For

a basic cabinet the leakage rate is

TABLE 6 Savings summary.

SAV INGS ITEM

BASIC (KWH)

H IGH PERFORMANCE

(KWH)DI FFERENCE

(KWH) PERCENT $/YR CO2

GAS 901,508 801,341 100,167 11 2,634 51,085

DX COOLING 82,470 74,973 7,497 9 750 12,520

FANS 59,860 43,261 16,599 28 1,660 27,720

CASING 45,370 10,562 34,808 77 968 18,420

TOTAL 1,089,208 930,137 159,071 6,012 109,745

* It is possible to build a single-wall casing with fiberglass insulation that has a deflection of L/240 or less. Many high-end custom AHU manufacturers do this. It is less common in packaged rooftop units.

TECHNICAL FEATURE



project location should point out where to recommend

increased product performance.

Operating hours will also impact savings. For this anal-

ysis, the assumption was 24/7 operation. In many appli-

cations, the MUA unit may only see 30% to 50% operating

hours, which will cut the annual savings and prolong the

payback period.

There are other things that can be done to reduce

energy usage including:

• Reducing operating time (don’t run it unless you

have to).

• Considering demand control ventilation or some

other means of reducing the supply airflow when pos-

sible. This improves the value of the direct drive plenum

fans with VFDs.

• Use low leakage outdoor air dampers to reduce

infiltration when the unit is off. In very cold climates

consider insulated low leak dampers.

• Consider face and bypass DX coil arrangements to re-

duce the condensing unit size (this requires expanding the

RH comfort criteria). This will cut the cooling load in half

reducing the first cost and operating cost. It will also avoid

the need for any reheat; however, dehumidification will be

reduced. In many applications this may be acceptable.

• Evaporative cooling (depending on location).

• Single air path (reheat) or dual air path energy

recovery. A dual air path energy recovery unit can offer

substantial savings however at a higher first cost for

both the unit and the return air ducting work. ASHRAE

Standard 90.1 has requirements for exhaust air energy

recovery depending on location and application. The

proposed energy savings outlined in this article would

also apply to an energy recovery MUA unit.

References1. ANSI Z83.8/CSA 2.6 -2013, Standard for Gas Unit Heaters, Gas Pack-

aged Heaters, Gas Utility Heaters and Gas-Fired Duct Furnaces.2. ANSI/ASHRAE/IES Standard 90.1 -2013, Energy Standard For

Buildings Except Low-Rise Residential Buildings.3. Natural Gas and Electricity rates are based 2013 U.S. Energy

Information Administration.4. ANSI/ASHRAE/USGBC/IES Standard 189.1 -2009, Standard for

the Design of High Performance Green Buildings. Table 7.5.3. 5. Crowther, H. 2014. “Air Leakage in Air Handling Units.” Price

Industries White Paper.

TECHNICAL FEATURE


TECHNICAL FEATURE | Fundamentals at Work

Kwang Woo Kim, Arch.D., is a professor of architecture at Seoul National University, Seoul, South Korea, and president of Architectural Institute of Korea. Bjarne W. Olesen, Ph.D., is director, professor, International Centre for Indoor Environment and Energy, Technical University of Denmark in Lyngby, Denmark, and vice president of ASHRAE.

The control of radiant heating and cooling system can

be classified as central control, zone control and individ-

ual room control. Figure 1 is a diagram on the principles

of control.

The central control controls the supply water tempera-

ture for the radiant system based on the outside tem-

perature. The room control then controls the water flow

rate or water temperature for each room according to

the room setpoint temperature.

Instead of controlling the supply water tempera-

ture, it is recommended to control the average water

temperature (mean value of supply and return water

temperature) according to outside and/or indoor tem-

peratures. During the heating period, as the internal

load increases, the heat output from the radiant system

will decrease and the return temperature will rise. If the

control system controls the average water temperature,

Control of the of the of heating and heating and heating cooling system cooling system cooling needs to be able to maintain the indoortemperatures within the comfort range under the varying internal varying internal varying loads and exter-nal climates. To maintain a stable thermal environment, the control system needsto maintain the balance between the heat gain/loss of the of the of building and building and building the suppliedenergy fromenergy fromenergy the system. Several studies in the literature deal with control.1–4

the supply water temperature will automatically

decrease due to the increased return water temperature.

This will result in a faster and more accurate control

of the thermal output to the space and will give better

energy performance than controlling the supply water

temperature.

Radiant surface cooling systems need controls to avoid

condensation. This can be done by a central control of

the supply water temperature limiting the minimum

water temperature based on the zone with the highest

dew-point temperature. If the supply water tempera-

ture is limited, the temperature of the rest of system

will be higher than the dew point, and there is no risk

of condensation on the pipes, and on the surface of the

radiant system. Limiting the supply water temperature

will lower the cooling power of a radiant system at high

indoor humidity levels. Dehumidifying the ventilation

BY KWANG WOO KIM, ARCH.D., MEMBER ASHRAE; BJARNE W. OLESEN, PH.D., FELLOW ASHRAE

Radiant Heating and Heating and HeatingCooling SystemsCooling SystemsCooling

Part TwoPart TwoPart


TECHNICAL FEATURE

air will result in lower dew-point temperature and will

allow higher cooling capacity of a radiant system.

Larger buildings should be divided in several different

thermal zones to optimize energy and control perfor-

mance. Each zone can be controlled with reference to

a temperature sensor in a representative space of the

zone.

For the improved comfort and further energy savings,

use an individual room temperature control. Each valve

on the manifold is controlled by each room thermo-

stat. An apartment or one-family house normally was

regarded as one zone, but installing thermostats for each

room is becoming popular. For better thermal comfort,

it is preferable to control the room temperature as a

function of the operative temperature.6

The heat capacity of surfaces with embedded pipes

plays a significant role for the thermodynamic proper-

ties of the heating system and, hence, for the control

strategy. An obvious consequence of the response time

of a conventional floor structures is that the instant

control of the heating power is not necessary. The tem-

perature of heat transfer medium, the time response

and the thermal capacity of systems depends on the

thickness of the surface layer where the pipes are

embedded.

For a low-temperature heating and high-temper-

ature cooling system, a significant effect is the “self-

regulating” control. This “self-regulating” depends

partly on the temperature difference between room

and heated/cooled surface, and partly on the differ-

ence between room and the average water tempera-

ture in the embedded pipes. This impact is bigger

for systems with surface temperatures close to room

temperature because the small temperature change

represents a higher percentage compared to the same

temperature change at a high temperature differ-

ence. The self-regulating effect supports the control

equipment in maintaining a stable thermal environ-

ment, and providing comfort to the persons in the

room.

For TABS, the concrete slab can be controlled at a

near constant core (water) temperature year-round.

Therefore, zone control (south-north), rather than indi-

vidual room control is more appropriate, because zone

level supply water temperature, average water tempera-

ture or flow rate control would be possible. Relatively

small temperature differences between the heated or

cooled surface and the space would result in a signifi-

cant degree of self-control.

As a TABS is not removing the room load imme-

diately, the control cannot keep a constant room

temperature during the day. Instead, a small room

temperature drift will result. An example from a

simulation is shown in Figure 2. The figure is compa-

rable with Figure 8 of Part 1 showing the energy flows.

Water of 20°C (68°F) is circulating in the concrete

slab from 6 p.m. to 8 a.m. the next morning. It can be

seen that the room is kept within the comfort range

of –0.5<PMV<+0.5. The operative temperature runs

between the line for air temperature and mean radi-

ant temperature and is within the comfort range of

23°C to 26°C (73.4°F to 78.8°F). This is an example on

how a dynamic building simulation may be used to

verify that by the used water temperatures or given

B = Boiler OTS = Outside Temperature SensorC = Chiller P = PumpCU = Control Unit RS = Room SensorPTS = Panel Temperature Sensor RTS = Return Medium Temperature SensorL = Limiter SOV = Shut Off ValveM = Manifold STS = Supply Medium Temperature SensorMC = Main Controller THS = Temperature-Humidity SensorMV = Mixing Valve

Figure

FigureRS

CU

M

PTS THS

B

RTS L STS

MC

C

MV

SOV

SOV

P OTS

FIGURE 1 Principal diagram of an embedded radiant heating and cooling system exemplified by a radiant floor system.5


chiller capacity the room will be

kept within the comfort range.

The objectives for the most eco-

nomic operation and operation

strategies of the building system

are the minimum total energy

costs and the minimum peak

electricity demand. As the radiant

system only can take care of sen-

sible heat load, the system needs to

be operated in combination with

air systems for ventilation, dehu-

midification and additional ther-

mal requirements. Therefore, the

system designer should consider TABS, the temperature variation of the water is very

small and the lifetime of the pipes are more than 100

years.

All couplings within the embedded construction

should be exactly located and designated on the record

drawing. The bending radius shall not be less than the

minimum bending radius defined in the relevant prod-

uct standards.

The thickness of the screed layer should be cal-

culated according to carrying capacity specified in

national codes. The screed thickness above pipes

must be at least 30 mm (1.2 in.). The temperature of

the liquid screed and the room should not be lower

than 5°C (41°F) for at least three days. Hardening

screed should be protected from draft, fast drying and

harmful effects.

Initial heating should be carried out in accordance

with the manufacturer’s instructions, but should be

maintained for at least seven days for systems with

anhydrite screeds. This operation commences at a sup-

ply temperature of between 20°C and 25°C (68°F and

77°F), which should be maintained for at least three

days. Subsequently, the maximum design temperature

should be imposed. The process of heating up must be

documented.

The thickness of the concrete for TABS should be cal-

culated according to load-bearing capacity specified

in national codes, and the position of pipes should be

considered in the gravity load calculation of the slab.

Pipes are commonly installed in the center of the con-

crete slab between the reinforcements. If the system is

constructed on site, the pipes are supplied in modules,

more energy-efficient HVAC systems and use of

renewable energy sources.

Another possible strategy is to reduce “room side”

energy demand. The room temperature control strategy

allowing a little fluctuation may bring significant energy

savings in comparison with keeping constant room tem-

peratures. Temperature fluctuations of up to 3 to 4K (5°F

to 7°F) per hour will not cause any additional comfort

problems as long as the room temperature is within the

specified comfort zone.

Installation For the installation of systems embedded in floor,

wall or ceiling, the manufacturer’s instructions must

be followed. To limit the heat flow toward the outside

(not exceed 10% of total heat flow) or to adjacent spaces,

a minimum thermal resistance of the insulating layer

shall be specified in the design. The effective thickness

of the insulating layer depends on the construction of

the radiant system. The thermal conditions under the

floor structure should be considered for an embedded

floor heating system insulation.

The dimensions of pipes must comply with the

requirements of the Standards. Minimal pipe thick-

ness should comply with the requirements for service

conditions, operation pressure (higher than 4 bar

[1,600 in. w.g.]) and durability (more than 50 years).

The use of plastic pipes with an oxygen-barrier layer is

recommended to reduce corrosion problems. However,

the risk for oxygen penetration is highest at very high

water temperatures, which you do not find in modern

buildings. For pipes embedded in concrete such as

FIGURE 2 Example of the temperature changes during a day in a space with TABS.

T Floor T mr T air

PMV

T ceiling

T water return

°F °C86.0 30

84.2 29

82.4 28

80.6 27

78.8 26

77.0 25

75.2 24

73.4 23

71.6 22

69.8 21

68.0 20

1

0.5

0

–0.5

–1

Pred

icted

Mea

n Vo

te

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0





which include a pipe coil attached

to the metal grid and equipped with

fittings.

Prior to embedding in screed or

concrete, the pipe circuits should

be checked for leaks by means of a

water pressure test. The test pres-

sure should be twice the working

pressure with a minimum of 6 bar

(2,400 in. w.g.). Where danger of

freezing water occurs during winter

installation, air can be used instead.

During the laying of the screed, this

pressure should be applied to the

pipes.

For TABS, the pipes are installed

during the main construction of

the building. This requires that the

decision on which heating-cooling

system to use must be made at an

early stage. It is also important that

the installation of the pipes do not

prolong the building construction

and costs. Therefore it is today pos-

sible to use prefabricated concrete

slabs with pipes embedded from the

producer’s side. For in-situ casting

of the concrete, it is recommended

to supply the pipes premounted on

mesh-like modules.

Applications Embedded surface systems are

used for heating and cooling in vari-

ous types of buildings. Principally,

ceiling systems are used as supple-

mentary air-conditioning systems

in non-residential office buildings.

The system can work with a quite

high cooling capacity of 50 to 100

W/m2 (16 to 32 Btu/h·ft²) limited by

the risk of condensation. Ceiling

heating is limited by standard

requirements for radiant asymme-

try to a capacity of 40 to 50 W/m2 (13

to 16 Btu/h·ft²) depending on ceil-

ing height. Floor and wall heating



systems are popular for residential

buildings, mostly in single family

houses and apartments because of

extra space created by embedding

the pipes in structure. The system

is suitable for spaces with heat-

ing loads of 10 to 100 W/m² (3 to 32

Btu/h·ft²) and cooling loads of 10

to 40 W/m² (3 to 13 Btu/h·ft²). The

warm surface is comfortable for

children playing on the floor. The

absence of radiators avoids injury in

rooms occupied by the elderly and

children.

Wall systems may limit furnish-

ing possibilities and the mounting

of wall pictures. Floor cooling sys-

tems in spaces that are influenced

by direct sunlight may rarely reach

a short-time cooling capacity of

more than 100 W/m² (32 Btu/h·ft²) if

unshaded and directly exposed.

Floor heating of high spaces

(large industrial building,

churches, etc.) ensures uniform

thermal conditioning and tem-

perature profiles in the occupied

space. The accumulated heat in

the floor of an aircraft hangar can

warm it up again in a half hour

after the aircraft moves out and

the doors closed. The system with

a heat conductive device or with

micro pipes requires a thin floor

construction, and can be used for

the renovation of buildings, as well

as for lightweight structure (e.g.,

wooden) buildings. In lightweight

building structures with a lack

of thermal mass, the installation

of TABS with PCM can be a solu-

tion. A PCM panel of 50 mm (2 in.)

thickness is able to store the same

amount of energy as a 250 mm

(10 in.) thick concrete slab. TABS

are usually installed into the ceil-

ing concrete slabs of multi-story

non-residential buildings. There

are also known application for

hospitals, museums, show rooms,

schools and libraries. TABS is suit-

able for buildings with cooling

loads up to 40 to 60 W/m² (13 to 19

Btu/h·ft²). In buildings with loads

over 60W/m² (19 Btu/h·ft²) the

installation of a complementary

convective system for cooling is

recommended in case of fast load

changes.

TABS is not fully suitable for instal-

lation as the only thermal condi-

tioning system in family houses,

as the user may want to reduce the

temperature level in sleeping rooms

during the daytime, when the room

is unoccupied. In that case an addi-

tional system for individual control

is required.

Examples of ApplicationsExamples of buildings in Canada

with embedded radiant heating and

cooling systems include:

• ICT Building at the University of

Calgary

• Gleneagles Community Centre,

West Vancouver, BC

• Kortwright Conservation Cen-

tre (Earth Rangers)

• Simon Fraser University Resi-

dences

• MacLeod II ECE Building (Fred

Kaiser Building) at the University of

British Columbia

• Manitoba Hydro Headquarters,

Winnipeg Manitoba

• Vancouver General Hospital

Cancer Research Centre

• Irving K. Barber Learning Cen-

tre, UBC

• City of North Vancouver Main

Library

Examples of buildings with a com-

bination of TABS and ground source


1

1 = Active Slab With Pipes 2 = Fresh Air Supply with Local Heating-Up3 = Air Exhaust and Cable Channel Above 4 = Lighting5 = Sun Screening/Shading 6 = Photovoltaic

FIGURE 4 Heat exchange and airflow pattern during cooling operation.7

6

6

6

5

5

2

2

4

4

1 3

31

mm

FIGURE 3 Typical temperature distribution in the floor/ceiling during cooling mode. 1 = linoleum, screed, wood plates, trapped air layer, concrete slab.

515

40

180

20

300

14023.2°C (73.8°F)

26°C (78.8°F)

18.3°C (64.9°F)

20.1°C (68.2°F)

20.9°C (69.6°F)21.3°C (70.3°F)

24.5°C (76.1°F)

heat pumps have been collected in an European project

(GEOTABS, http://www.geotabs.eu/Database).

Office Building in GermanyA 6,500 m² (70,000 ft²) and five-story annex build-

ing of an office in Stuttgart, Germany is installed

with thermally active building system (TABS) and a

mechanical ventilation system. The construction of the

slab is shown in Figure 3. The heat carrier circulates in

meandering pipe circuits (VPE pipes, 20 mm [0.8 in.]

diameter) embedded into the load-bearing 300 mm (12

in.) concrete ceiling. Piping material (VPE instead of

common PE-X) was chosen in accordance with higher

load strain of the slab due to the 15 m (49 ft) distance

between the columns. Total length of piping is about

49,000 m (160,000 ft) at 9,750 m² (105,000 ft²) of active

ceiling area.

The trapped air layer of 180 mm (7 in.) significantly

influences the heat conduction in the slab upwards

and the radiated heat released from the floor surface

(Figure 3). The air gap space is used for installation of IT

and electricity cables, water distribution and air duct

system.

Figure 4 shows the summer conditions of heat

exchange and room airflows. TABS is associated with

the air-conditioning system using 100% fresh air sup-

plied by plinth units (close to the façade), and floor

inlet units (building core area). The system controls the

individual room humidity and covers a percentage of

the peak loads (cooling ~10%, heating ~18%). The fresh

air inlet units provide 80 to 100 m3/h per person (47 to

59 cfm/person) corresponding to about 45 m³/h (26.5

cfm) and 1.57 ach. The air velocity is less than 0.11 m/s

(21.7 fpm) in 0.6 m (2 ft) distance from the inlet units

and the relative humidity varies between 45−60% (for

closed windows).

The mean water temperature in the activated slabs

is controlled according to outdoor temperature year

round. The actual supply water temperature varies

between 19°C to 23°C (66.2°F to 73.4°F). Using this

strategy, in conjunction with the ventilation system,

the room temperatures are maintained between 22°C

to 26°C (71.6°F to 78.8°F) in summer and 21°C to 24°C

(69.8°F to 75.2°F) in winter.

As the heat carrier in summer circulates only dur-

ing the night, power demand is greater during the

night time and takes advantage of the cheaper elec-

tricity night tariff. The field measurements result

showed operative temperature during working hours

were kept between 22°C to 25°C (71.6°F and 77°F) in

summer and 21°C to 23°C (69.8°F to 73.4°F) in winter

(Figure 5).8

TECHNICAL FEATURE


High-Rise Apartment Building in Korea In Korea, 100% of residential buildings are

heated with radiant floor heating systems.

Even the 300 m (984 ft) high, 80 story high-

rise residential apartment building “We’ve

the Zenith” (Figure 6), is heated with a radiant

floor heating system. Hot water is gener-

ated by boilers in rooftop mechanical room,

and serves seven vertical heating zones with

proper hot water temperature for radiant

floor heating after heat exchange.

University Building in KoreaEwha Womans University Campus Center

(ECC) in Seoul, Korea, is a good example of

non-residential building application (Figure

7). It is a university complex including lec-

ture rooms, offices and public spaces. ECC

is designed by Dominique Perrault and local

Baum Architects.

Accumulated energy in massive ceilings

is used by means of concrete core activa-

tion to reduce energy demand for thermal

well-being. The cooling with the concrete

core activation is done by chilled water tem-

peratures of 17°C (62.6°F) supply and 20°C

(68°F) return, and heating by hot water tem-

peratures of 29°C (84.2°F) supply and 26°C

(78.8°F) return.

The first step of the cooling is done by

the remaining cool energy of the return-

ing water to absorption chiller. The second

step is to use stored energy of the ground-

water storage tanks. The third step is to use

earth energy through the pipes under the

basement floor. The cooling energy for the

concrete core activation is supplied con-

tinuously over 24 hours, therefore, there is

no peak load and the sizes of all necessary

equipment could be reduced to a minimum.

Airport in BangkokThe international airport Bangkok, which

opened in September 2006, is thermally con-

ditioned by a floor surface cooling system in

combination with a displacement ventilation

system (Figure 8). Its 150 000 m² (1.6 milion

FIGURE 5 Sample of operative temperatures measured during a work week in an office building equipped with TABS. A = 4th floor east; B = 4th floor south; C = 5th floor east; D = 5th floor west; E = outside temperature.8

0 12 24 12 24 12 24 12 24 12 24

75.2

73.4

71.6

69.8

68.0

66.2

24

23

22

21

20

19

°F°C Heating Season (Winter)

Cooling Season (Summer)95.0

91.4

80.6

73.4

66.2

59.0

35

33

27

23

19

15

°F°C

0 12 24 12 24 12 24 12 24 12 24

A B C D E

FIGURE 6 High-rise apartment building, ‘We’ve the Zenith,’ with radiant floor heating system (Busan, South Korea). Left: Exterior view; Right: Mechanical system diagram of radiant system.

Compact HeatExchanger

B1 Floor Mechanical Room

HWS: 115°C (239°F)

HWR: 75°C (167°F)

HX HX

HX HX

HX HX

HX

HX

HX

HWS: 80°C (176°F)

HWR: 65°C (149°F)

HWS: 65°C (149°F)

HWR: 40°C (104°F)

31st FloorMechanical Room

59th Floor Mechanical Room

HWS: 65°C (149°F)

HWR: 40°C (104°F)

HWS: 65°C (149°F)

HWR: 40°C (104°F)

Rooftop Mechanical Room


C E I L I N G G R I D S Y S T E M

The Atlas Operating Room Ceiling System (AORCS) makes it quicker and easier to build critical environment spaces with future flexibility in mind. Each system is custom engineered to meet the requirements of codes and guidelines, such as ASHRAE Standard 170 and the Facility Guidelines Institute (FGI) ‘Guidelines for Design and construction of Hospitals and Outpatient Facilities.’ Used to support diffusers, blank-off panels, and light fixtures, the Atlas Ceiling System also creates a barrier between the space and ceiling ple-num to prevent transmission of contaminants.

For more information on the Atlas Operating Ceiling Grid System, visit https://www.titus-hvac.com/Products/Diffusers/AORCS.

AORCS

Integrated ceiling system offers simple, effective, and flexible solutions for hospitals and cleanrooms

Custom Engineered Solutions

Heavy-duty extruded aluminum construction

Antimicrobial powder-coat finish and gasket

Pre-cut at factory for rapid assembly in the field with “quick snap” connectors

“Quick snap” connectors allow for easy reconfiguration in the field

Factory supplied blank-off panels to match air distribution

Redefine your comfort zone. ™ | www.titus-hvac.comwww.info.hotims.com/54426-58


To provide both cool-

ing and ventilation, two

separate systems are com-

bined. The under-floor

cooling system directly

absorbs the solar gains

whilst maintaining a com-

fortable floor surface tem-

perature (minimum 21°C

[70oF]). The displacement

ventilation system with

a variable flow volume

provides dehumidified

fresh and re-circulated

air at floor level via an

approximately 2 m (6ft, 8

in.) high air diffuser. Due

to the warm climate the

temperature in winter

may achieve in average of

control performance of hydronic radiant heating systems based on the emulation using hardware-in-the-loop simulation”, Building and Environment 46(10).

3. Kang, D.H., et al. 2010. “Effect of MRT variation on the energy consumption in a PMV-controlled office.” Building and Environment 45:1914-1922. 2010.9.

4. Rhee, K.N., Ryu, S.R., Yeo, M.S., Kim, K.W. 2010. “Simulation study on hydronic balancing to improve individual room control for radiant floor heating system.” Building Services Engineering Research and Technology 31(1):57–73.

5. ISO 11855-6: 2012. Building environment design - Design, dimension-ing, installation and control of the embedded radiant heating and cooling systems – Part 6: Control.

6. Olesen, B.W. 1997. “Possibilities and limitations of radiant floor cooling.” ASHRAE Transactions 103(1):42–48.

7. Wiercioch, H. 2001. Betriebserfahrung mit Betonkernaktivier-ung, BV M+W Zander Stuttgart, In proc: 23.Velta kongress 2001, Wirsbo-Velta, Nordestedt, Germany.

8. De Carli, M., Olesen, B.W. 2001. “Field measurement of thermal comfort conditions in building with radiant surface cooling sys-tem.” Clima 2000.

FIGURE 7 ECC with TABS and radiant ceiling panel (Seoul, South Korea). Left: Exterior view of ECC; Right: Radiant ceiling panels.

FIGURE 8 Bangkok Airport (Bangkok, Thailand). Top Left: Concourse building shell; Top Right: Interior membrane; Bottom Left: Installation of floor cooling: Bottom Right: Boundary conditions and simulated temperatures in the concourse, 20°C (68°F) Blue; 30°C (86°F) Deep Green; 40°C (104°F) Red.1

ft²) of cooled floor area, comparable

to 20 football fields, is recognized as

the world’s largest application. With

the length of 440 m (1,440 ft) and a

width of 110 m (360 ft) and an area of

almost 500 000 m² (5.2 million ft²)

the terminal became the largest com-

bined building complex of its kind in

the world. The H-shaped concourses

have a total length of 3.5 km (2.2

miles).

21°C (70°F) during the night (summer 25°C [77°F]) and

31°C (88°F) during the day (summer 34°C [93°F]). The

solar radiation usually incidents perpendicularly to the

earth’s surface and reaches the level up to 1,000 W/m²

(300 Btu/ h·ft²). Due to the narrow range of the operative

temperature at 24°C (75°F) and a relative humidity of

between 50 and 60% during the 24 opening period the

airport requires constant cooling and dehumidification.

AcknowledgmentsThis article was supported by VELUX guest professorship, and a grant from the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2014-050381).

References1. Olesen, B.W. 2001. “Control of floor heating and cooling sys-

tems.” Clima 2000/Napoli 2001 World Congress.2. Rhee, K.N., Yeo, Myoung S., Kim, K.W. 2011. “Evaluation of the



COLUMN ENGINEER’S NOTEBOOK

Steven T. Taylor

Return AirReturn AirReturn Systems Air Systems Air

Steven T. Taylor, P.E., is a principal of Taylor Engineering in Alameda, Calif. He is a mem-ber of SSPC 90.1 and chair of TC 4.3, Ventilation Requirements and Infiltration.

BY STEVEN T. TAYLOR, P.E., FELLOW ASHRAE

or relief fans in lieu of less efficient return fans, which

are generally required when return air is fully ducted.1,2

• Little or no balancing costs for the return air system

and, for VAV systems, balance is better maintained as

supply airflow rate varies as loads vary. Ducted return

systems can only be balanced at one condition, generally

at design airflow rates, and are inherently unbalanced

at other conditions, possibly leading to overly positive or

negative space pressurization.

• Reduced noise transfer between rooms. Sheet metal

ducts, if unlined, are very adept at channeling crosstalk

from room to room,* much more so than a large ceiling

plenum where noise can dissipate.

Disadvantages of Architectural Return Air PlenumsOn the other hand, using architectural plenums has

some potential disadvantages:

• There is the possibility of indoor air quality prob-

lems in humid climates if the architectural plenum is

negatively pressurized to the outdoors.3 Humid out-

door air can be drawn into the architectural plenum

and cooled below the dew point, causing condensation

and subsequent mold and mildew problems within the

structure. This potential problem can be avoided by sim-

ply not allowing the architectural plenums to become

negatively pressurized relative to outdoors. For example,

a return air plenum can be easily designed and con-

trolled to be positively pressured. First, the building can

be controlled to be pressurized to about 0.05 in. w.c.

(12.5 Pa),4 and ceiling return air grilles can be selected

to have a pressure drop of only about 0.02 in. w.c. (5 Pa).

The ceiling plenum will thus be positive 0.03 in.w.c. (7.5

Most HVAC systems at least partially recirculate partially recirculate partially air to increase cooling or cooling or cooling heatingcapacity tocapacity tocapacity conditioned spaces while avoiding the avoiding the avoiding energy and energy and energy first cost impact ofconditioning outdoorconditioning outdoorconditioning air. These systems generally take generally take generally one of the of the of following forms: following forms: following

• Return air is conveyed entirely in ductwork from

the conditioned space back to the air-handling unit;

• Return air is conveyed entirely using architectural

plenums such as ceiling cavities, drywall shafts, and

mechanical rooms; or

• A combination of ductwork and architectural ple-

nums.

Using architectural plenums is prohibited in some

applications. For instance, most model mechanical

codes do not allow conveying air in plenums exposed

to materials that do not meet certain flame spread and

smoke generation limits, such as wood beams or trusses.

Most health-care codes also prohibit the use of archi-

tectural plenums for critical medical spaces because of

concern about asepsis. But for most commercial and

residential applications, architectural plenums can be

used.

Benefits of Architectural Return Air PlenumsThe benefits of using architectural plenums vs. duct-

work include:

• Reduced HVAC system costs of about $3 to $5 per

square foot ($32 to $54 per square meter), about 10% to

20% of the total HVAC system cost.

• Reduced costs to other trades to accommodate the

congestion caused by the added return air ductwork,

such as raising the floor-to-floor height or adding ad-

ditional offsets in plumbing and sprinkler piping.

• Reduced fan energy costs of about 20% to 30% due

to the much lower pressure drop of the plenum return

system.

• Reduced fan energy in systems with outdoor air

economizers due to the ability to use non-powered relief *The author experienced this firsthand with a home that was custom built for the previous owner who required that the furnace be fully ducted to each room with unlined sheet metal ducts. My teenage children entertained themselves for hours spying on each other by listening through the return air grilles. The first modification my wife and I made to the house was to blank off the return air grille to our bedroom…



Pa) relative to the outdoors (Figure 1; note that all pres-

sures shown are relative to outdoors). Of course, wind

pressure and stack effect can overwhelm these small-

positive pressures, but that is true of both plenum and

ducted return air systems.

• Figure 1 shows that while the ceiling return air

plenum is positive to the outdoors, the shaft is not. It is

generally not practical for the shaft to be designed to be

positive to the outdoors without overpressurizing the

space. In humid climates, it is critical that the architec-

tural return shaft be completely disconnected from the

exterior walls; if the structure is built so this negative

pressure is seen at the exterior wall, moisture and

mold problems can result. This disconnect is generally

not an issue for steel and concrete structures, but may

be for wood construction typical of residential build-

ings. In the latter case, ducting the return air riser

(Figure 2a) is a good idea versus unducted (Figure 2b). It

may also be required by code if the return air system

is being used for smoke exhaust such as in a high-rise

building. But many engineers duct the return air riser

even when leakage into the riser is simply return air

from the conditioned space, not from the outdoors.

Shaft leakage does not matter in this case – the air

leaked into the shaft is the same air that is drawn into

the return air duct. Ducting the riser in this case adds

to first costs, energy costs, and space requirements

and can cause imbalances in airflow between floors as

supply air and return air rates vary in VAV systems. If

the shaft is unducted and sized for low velocity (less

than 1000 fpm [5 m/s] through the free area at the top

of the shaft), airflow pressure drop from top to bottom

is small, making the shaft nearly self-balancing. Again,

stack effect may also cause imbalances, but that is true

both ducted and unducted risers.

• Some indoor air quality specialists point out that

even dry architectural plenums can be potential sources

of indoor air quality pollutants such as particles. A ceil-

ing return air plenum that has been used for a few years

could have substantial dust accumulation on plenum

surfaces. But return air ducts could have a similar or

even thicker layer of dust. The dust “challenge” for both

are particles drawn from the conditioned space and the

source strength of these particles is the same whether

the return air is ducted or an architectural plenum.

In both cases, the air will be filtered at the air handler

before the recirculated air is supplied to the space, so in

both cases, this is generally a non-issue from an indoor

air quality perspective. Particle challenges from outdoor

ventilation air are usually much greater.

• It is common for full height (slab-to-slab) walls to

be provided as acoustical barriers for noise sensitive

spaces, such as conference rooms. An acoustic return air

transfer “boot” must be provided at these spaces to allow

return air to transfer from them to the ceiling plenum

or to the adjacent space. Figure 3 shows an inexpensive

sound boot: it is composed of a standard 5 ft (1.5 m) duct

section that can be produced from a typical “coil line”

duct making machine, which reduces its cost relative to

a hand fabricated zee-shaped duct or elbow although

acoustic performance of the latter may be better. Rules

of thumb for sizing various return air transfer assem-

blies are shown in Table 1.

• Maintaining a low pressure drop return air path from

conditioned spaces to the air handler can be a challenge

using architectural plenums when spaces are divided by

FIGURE 1 Typical pressures: Plenum return.

–0.02 R.A. Ceiling Plenum +0.03 in.–0.05

R.A. S

haft

+0.05

FIGURE 2 Return air risers.

Ducted UnductedA. B.

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many floor-to-floor partitions, such as acoustical parti-

tions, tenant separation walls, and rated corridor walls.

Where there are multiple partitions between the air

handler or return air shaft and the most remote rooms,

return air transfer openings and sound boots must be sized

for even lower velocities and get progressively larger (Figure

4) to ensure that the overall pressure drop remains low to

FIGURE 3 Inexpensive return air sound boot. TABLE 1 Rule-of-thumb design velocities for transfer assemblies.

NO.INLET

LOCATIONDISCHARGE

LOCATIONAPPLICATION

DUCT S IZ ING RULE OF THUMB

FPM

1 Return Air Plenum

Return Air Plenum

Lined 5 ft Boot (Figure 3) 800

2 Return Air Plenum

Return Air Plenum Flex Duct Both Sides 750

3 Return Air Plenum

Return Air Plenum

Single Elbow (No Turning Vanes) 700

4 Return Air Plenum

Return Air Plenum

Double Elbow Both Sides (No Turning Vanes) 575

5 Ceiling Grille Return Air Plenum

Flex Duct to Perforated Face Grille 500

6 Ceiling Grille Ceiling Grille Flex Duct to Perforated Face Grilles 350

7 Return Air Plenum Ceiling Grille Toilet Makeup.

Flex Duct to Perforated Face 325

The velocities are intended to result in a 0.08 in.w.c. (20 Pa) pressure drop across the transfer as-sembly including pressure drop of entrance, exit, duct, and grilles. Return air plenum is assumed to be 0.02 in. w.c. (5 Pa) relative to the space for Application 5 and 0.05 in. w.c. (12 Pa) for Application 7. Note that these are for a single return air transfer – for multiple boots in series (e.g., cascading from one room to another before it gets to the shaft), velocities must be even lower so the total pressure drop does not exceed 0.08 in. from furthest room to shaft or fan room to ensure exterior plenum walls are positively pressurized relative to the outdoors.

WallWall

Lined Transfer Boot



avoid negative plenum pressures relative to the outdoors

around the building perimeter. There are applications

where this necessitates such large return air boots that

ducting the return air may be the right choice. But this is

seldom or never true when the ceiling is not divided by full

height walls. Many engineers partially duct return air into

ceiling plenums to “within no more than 30 ft” (or other

rule-of-thumb) of return air grilles believing that this

improves return air performance. In the author’s opinion,

there is no value to these duct extensions and they add to

first costs and energy costs. If there is room in the ceiling

for the return air duct, there is even more room in the

return air plenum without the duct, so velocity and pres-

sure drop will be lower if the duct is eliminated.

Diagnosing Return Air ProblemsA common misdiagnosis is that a room is undercooled

“because it has no return air path—the air is trapped.”

However, this is almost never the case with ducted sup-

ply air systems such as VAV systems. This is because

the walls and ceiling enclosing a typical room are not

so airtight that they can cause enough backpressure to

prevent air from the supply air fan from being supplied

to the room.† If supply airflow to a room is verified by

a flow hood, VAV box airflow sensor, or other airflow

measuring device, the room is being conditioned even if

there is no obvious return air path; air is simply leaving

the room through leaks in walls, ceilings, doors, etc. To

verify this, simply compare the measured supply airflow

rate with the doors to the room open and then closed.

So a constricted return air path will seldom cause tem-

perature control problems. But they can create differen-

tial pressure problems resulting in doors being pushed

closed or open and audible airflow noise at leakage

points such as around doors.

If the air handler has an airside economizer, these

same symptoms can also be caused by an ineffective

relief air path, such as an undersized non-powered

relief (barometric) damper or undersized relief fan

(powered exhaust). To determine which path, return or

relief, is the cause, perform this simple test:

1. Configure the economizer dampers for zero outdoor

air, zero exhaust air, and 100% return air.

2. If the system has a relief fan, turn it off. If it has a

return fan that is controlled by airflow tracking,4 control

† This rule is generally not true of low pressure unducted systems such as underfloor air distribution (UFAD) systems. The floor pressure is generally very low, less than 0.1 in. w.c. (25 Pa), so backpressure caused by a restricted return air path from a room can restrict supply airflow and thus cause temperature control problems.

the fan with zero offset. If the return fan has direct

building pressure control, disable this control so the

relief damper is closed.

3. Open VAV boxes as required to simulate full design

conditions.

4. Run the supply air fan under normal control.

If the building or room pressures are excessive during

this test, the return air path is constricted. If not, the

relief system is the source of the problem. This could be

verified by configuring the system in 100% outdoor air,

100% exhaust mode.

Once the constricted path is identified, the pinch point

or points can be identified by measuring static pressure

along the path looking for excessive pressure drops.

Conclusions and RecommendationsThe benefits of using architectural plenums for return

air are substantial, including much lower first costs and

lower energy costs. In most cases, the design is also easy:

just ensure that each space has a low pressure return air

path back to the air handler. But where there are many

full height walls and other constrictions, care must be

taken to ensure that the low velocity return air path is

maintained by properly sizing transfer ducts and sound

boots.

References1. Taylor, S. 2000. “Comparing economizer relief systems.”

ASHRAE Journal (9).2. Kettler, J. 2004. “Return fans or relief fans.” ASHRAE Journal (4). 3. Lstiburek, J. 2009. “Fundamental changes in the last 50 years.”

ASHRAE Journal (7).4. Taylor, S. 2014. “Controlling return air fans in VAV systems.”

ASHRAE Journal (10).

FIGURE 4 Return air boots in series.

–0.03 in. +0.03 in.–0.02 –0.05

R.A. S

haft

+0.05

+0.00 in.



COLUMN BUILDING SCIENCES

Joseph W. Lstiburek

BY JOSEPH W. LSTIBUREK, PH.D., P.ENG., FELLOW ASHRAE

Things have evolved considerably evolved considerably evolved since considerably since considerablythe Eisenhower and Eisenhower and Eisenhower Diefenbaker and Diefenbaker and years. Diefenbaker years. DiefenbakerHutcheon† taught us about airflow that airflow that airflowdecade but it took more took more took than a half century half century halfto get it right. We needed air needed air needed control. air control. air Weneeded anneeded anneeded air an air an control air control air layer control layer control – layer – layer an – an – air an air an barrier. air barrier. airWe started off started off started with off with off locating with locating with it locating it locating on it on it the on the on insideand finallyand finallyand ended finally ended finally up ended up ended with it with it with on it on it the on the on outside.‡

We started by started by started combining by combining by it combining it combining with it with it a with a with vapor a vapor abarrier onbarrier onbarrier the on the on inside then we then we then finished by finished by finishedcombining itcombining itcombining with it with it a with a with weather a weather a resistive weather resistive weather barrier(WRB) and continuous and continuous and insulation on insulation on insulation the on the onoutside (Figures (Figures ( 1Figures 1Figures through 5)through 5)through .

Throughout the postwar years practitioners were

taught, incorrectly, that vapor barriers were necessary in

cold climates to protect wall assemblies from moisture

damage and that it was necessary to install these vapor

barriers on the interior of cavity insulation. The industry

saw the introduction of kraft facings and foil facings on

batt insulations as a result. These vapor barriers were by

their very nature discontinuous and they proved inef-

fective in protecting wall assemblies from vapor. Vapor

is principally transported by airflow not by vapor diffu-

sion. We needed air barriers not vapor barriers to con-

trol vapor flow. It took decades for that distinction to be

appreciated.§

Evolution of the Residential Air Barrier

Forty YearsForty YearsForty ofAir BarriersAir BarriersAir *

* This is a play on the title of Professor Hutcheon’s classic paper “Forty Years of Vapor Barriers.” Read down a couple of footnotes and enjoy….† Hutcheon, N.B.; “Fundamental Consideration in the Design of Exterior Walls for Building.” NRC Paper No. 3087, DBR No. 37. Division of Building Research, National Research Council of Canada, Ottawa, 1953.‡ At the turn of the 20th Century it became common to install a layer of rosin paper over wood board sheathing and under clapboard siding (see “The Evolution of Walls,” ASHRAE Journal, June 2009) to reduce drafts. This rosin paper was an early “air barrier.” Having pointed this out, I am going to conveniently ignore this fact because it messes with my narrative.§ “It was 30 years from the time of Rowley’s paper before it was clearly established and widely accepted that the leakage of air from inside a building through constructions, and not vapor diffusion alone, was often the principal means by which water vapor moved to cold surfaces. The concept of vapor diffusion was not wrong, but it was not the only way. It is incredible, in retrospect, that it should have taken so long to reach this conclusion….” N. B. Hutcheon, from “Forty Years of Vapor Barriers,” Canadian Consulting Engineer, special publication on Moisture Control, Ottawa, 1978.

PHOTO 1 Plastic Vapor Barrier. Not a “production friendly” method of achieving airtightness and it was not “robust” in terms of surviving the construction process and in providing performance over the service life of the building. It was also cli-mate sensitive. It made no sense for assemblies that saw air conditioning. It was a vapor barrier on the wrong side of such assemblies.

The first attempt at addressing the issue was to take

a vapor barrier material and turn it into an air bar-

rier. The result was coined an “air-vapor barrier.” Sheet

polyethylene was already being installed on the interior

of insulated wall assemblies as a vapor barrier (Photo

1). It was given a second function—that of air control.

Easy to do conceptually—very difficult to do in practice.

With painstaking effort and attention to detail, extraor-

dinary levels of airtightness were achieved using this

approach—less than 1 ach at 50 Pa. Canada’s R-2000

program was based on this approach. The sealant used

was “acoustical sealant” as it would remain flexible over

the service life of the building. It soon got the moniker

of “black death” as it got on to everything including the

installer. It became clear that the approach was not a

“production friendly” method of achieving airtightness

and it was not “robust” in terms of surviving the con-

struction process and in providing performance over the

service life of the building. It was also climate sensitive.

It made no sense for assemblies that saw air condition-

ing—it was a vapor barrier on the wrong side of an air-

conditioned wall (Figure 1).



Joseph W. Lstiburek, Ph.D., P.Eng., is a principal of Building Science Corporation in Westford, Mass. Visit www.buildingscience.com.

The next step in the evolution of the air barrier was the

“airtight drywall approach” (Figure 2)—where the interior

gypsum board lining became the air barrier (Photo 2). Sheet

polyethylene was no longer necessary. The approach was

more robust than polyethylene air-vapor barriers and since

gypsum board was not a vapor barrier the approach could

be used in any climate. However, to get to similar extraordi-

nary levels of airtightness as those being achieved with the

poly approach in the R-2000 program, painstaking effort

was still required. Most production builders concluded

such levels of airtightness were not worth the effort.

The focus shifted to targeting only the interior big

holes using sealed rigid draft-stopping. Bathtubs and

FIGURE 1 Polyethylene Air-Vapor Barrier. The period of “black death” where acoustical sealant that was black in color was used to seal overlapping sheets of 6 mil polyethylene to create a continuous air barrier. Note that where the mem-brane sheet wrapped the exterior rim joist it needed to be vapor open. Vapor open “housewraps” or plastic building papers were used in these locations.

FIGURE 2 The “Airtight Drywall Approach.”The interior gypsum board lining became the air barrier. The approach was more robust than polyethylene air-vapor barriers and since gypsum board was not a vapor barrier the approach could be used in any climate. However to get to similar extraordinary levels of airtightness painstaking effort was still required. PHOTO 2 Interior Gypsum Board as the Air Barrier. Note the sealant at the bottom plates and around window openings.


PHOTO 3 (LEFT) Bathtub on Exterior Wall. Targeting the big holes with rigid draft-stopping. Of course, an even better approach is not have a bathtub on an exterior wall. PHOTO 4 (R IGHT) One-Piece Tub Shower Enclosures. A really, really big hole on an exterior wall sealed by a very happy builder. Note the sealant around the perimeter of the rigid draft-stopping, sealing the draft-stopping to the framing.

FIGURE 3 Air Infiltration Barrier. Plastic housewraps were developed and had two functions: rainwater control and air control. PHOTO 5 Air Infiltration Barrier. Classic housewrap rainwater control layer and air control layer. Note the beautiful job of flashing integration with the housewrap. The outside is the right place for air control.

shower enclosures on exterior walls, fireplace assemblies

on exterior walls, soffits deadending in exterior walls,

dropped ceilings at enclosure perimeters, garage-to-house

connections and cantilevers (Photos 3 and 4). A “lite” version

“airtight drywall approach.” It became relatively easy for

production home builders to get below 3 ach at 50 Pa and

the approach morphed into the EPA Energy Star “thermal

bypass checklist” and eventually found its way into the

model codes.#

But getting to 1 ach at 50 Pa if you were a production

builder needed rethinking the problem. There were too

many problems with locating the air barrier on the interior.

Penetrations from electrical boxes, plumbing, intersecting

interior walls and intermediate floor framing made very

high levels of airtightness impossible for production home

builders with interior air barriers. The focus shifted to the

outside.

Why not turn the exterior building paper into the air

barrier? Tar paper was already being used for rainwater

control purposes. Why not turn it into an air barrier? Good

idea in principle, but tar paper was not the product up to

the task. You could not tape tar paper and it only came in nar-

row rolls.II Plastic housewraps were developed and the exterior

“air infiltration barrier”** was introduced (Figure 3 and Photo 5).

It was an amazing transformation in retrospect. Tar paper

was introduced first to control air and then it took on a rain

control function. Its original air control function was for-

gotten when sheet goods such as plywood and OSB replaced

exterior (and very air leaky) board sheathing. Now the air

control function was back. But to a production builder, the

water control function was still more important. And for

good reason. Builders do not get calls in the middle of the

night saying their buildings are leaking air, but they do get

those calls when they are leaking rainwater.

# The 2012 IECC requires that homes in cold climates are constructed such that they are less than 3 ach at 50 Pa and the “thermal bypass checklist” is prescriptively listed as a code requirement. II And you couldn’t print advertising and logos on it to turn your building into a billboard.** Tar paper was originally introduced 100 years earlier to keep drafts out of exterior walls; hence the initial focus on “air infiltration” rather than airflow from both the interior and exterior.


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PHOTO 6 (LEFT) Robust Rainwater Control. Many elegant and clever accessories were introduced to deal with rainwater control particularly at window-to-wall interfaces. This is a formable and flexible membrane “pan flashing” system. PHOTO 7 (RIGHT) More Robust Rainwater Control. Beautiful “under window gutter,” pan flashing, sealed to the interior of the window unit for air barrier continuity.

PHOTO 8 Fully Adhered Membrane. Ultra-high levels of airtight-ness with ultra-high levels of cost. Not the easiest stuff to install either. I should know, this is my place.

PHOTO 9 (LEFT) Fluid-Applied Air Barrier. The coatings needed to be able to span joints, and they needed to be vapor permeable. And their most important function, rainwater control, could not be compro-mised. PHOTO 10 (RIGHT) Water Control/Air Control Continuity. The fluid-applied coating must connect to the air control layer of the roof assembly and to the air control layer of the foundation assembly.

PHOTO 11 (LEFT6) Window Opening. Origami is not a necessary skill with fluid-applied flashing systems. PHOTO 12 (RIGHT) Another Window Opening. Some systems require fabric reinforce-ment at critical interfaces.

The “new” air infiltration barriers needed

to be robust rainwater control layers. Many

elegant and clever accessories were intro-

duced to deal with rainwater control partic-

ularly at window-to-wall interfaces (Photos 6

and 7).

But very high levels of airtightness were

still elusive to production builders using

exterior housewraps. They were difficult

to work with—flexible films on the exterior

proved to have similar issues to the experi-

ence with flexible films on the interior.

How about fully adhered membranes?

Yup, they worked big time (Photo 8). Ultra

high levels of airtightness were achiev-

able—but at ultra high levels of cost. This

was a great commercial building enclo-

sure technology that failed to get traction

residentially mostly due to cost. They were

not easiest thing to install either. There

were also physics related issues. Until

very recently no vapor open fully adhered

membranes were available, which meant

that insulation needed to be installed outboard of the

membranes to control the temperature of the condens-

ing surface during heating—the condensing surface

being the interior of the exterior sheathing—typically

plywood or OSB.

On the commercial side fluid-applied air barriers

began to make inroads due to their competitive cost

and relative ease of installation. It was only a matter of

time before they appeared residentially (Photos 9 and

10). Overcoming the technical challenges has not proven

to be easy. The coatings needed to be able to span joints

and they needed to be vapor permeable. And their most

important function, rainwater control could not be com-

promised. After a decade of experience—principally on

the commercial side—we are seeing products that are

working. Origami is no longer a required skill to flash a

window opening (Photos 11 and 12).††

†† Why not just get rid of the damn window? It is a big thermal hole in the wall. It leaks rainwater. Itleaks air. It is expensive. My life as an engineer would be so much simpler. This, of course, is why wedo not let engineers design buildings that people actually live in and work in. We need architects.


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FIGURE 4 (LEFT) Exterior Sheathing Air Barrier. Turning the sheathing itself into both the water control layer and air control layer. PHOTO 13 (TOP) Sheathing Water and Air Control Layer. The sheathing in this system is pre-coated with a water control layer. Tape is used to provide water control and air control layer continuity. FIGURE 5 (RIGHT) Insulating Sheathing Air Barrier. Adding the function of thermal control to the sheathing in addition to water control and air control. PHOTO 14 (BOTTOM) Insulating Sheathing Water and Air Control Layer. The insulating sheathing provides three functions in this approach: water control, air control and thermal control.


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What about turning the sheath-

ing itself into both the water con-

trol layer and air control layer?

Yes, see Figure 4 and Photo 13. You

could even have the sheathing be

the thermal control layer (Figure 5

and Photo 14).

You still need to deal with the

joints of course. Tapes are cur-

rently the technology of choice,

but I see that changing. I see fluid-

applied joint systems replacing

tapes—due to speed, cost, surface

adhesion advantages and appli-

cation temperature advantages

(Photo 15).

So where are we after 40 years?

We went from the interior to the

exterior with air barriers. And we

went from combining the vapor

barrier with the air barrier on

the inside to combining the water

control layer with the air barrier

on the outside. We went from films

on the inside to sheet goods on the

inside. Then we went from films

on the outside to sheet goods on

the outside. We went from caulk-

ing and the black death on the

inside to tapes and fluid-applied

joint systems on the outside. We

are not done of course. But we are

well on the way. It is only a matter

of time that production builders

move the airtightness bar from 3

ach at 50 Pa to 1 ach at 50 Pa.

BibliographyHutcheon, N.B. 1953. “Fundamental

Consideration in the Design of Exterior Walls for Building.” NRC Paper No. 3087, DBR No. 37. Division of Building Research, National Research Council of Canada.

PHOTO 15 Fluid-Applied Joint System. Replacing tapes with fluid-applied joint systems is now possible.

Hutcheon, N.B. 1978. “Forty Years of VaporBarriers.” Canadian Consulting Engineer, special publication on Moisture Control.

Rowley, F.B., “A Theory Covering the Transfer of Vapor Through Materials.” ASHVE Transactions 45:545, 1939.



TECHNICAL FEATURE

Mark Hydeman, P.E., is a principal of Taylor Engineering, LLC. He was the principal investigator of RP-1455 and is the chair of GPC-36. Steven T. Taylor, P.E., is a principal of Taylor Engineering LLC. He is the research chair for TC 1.4. Brent Eubanks, P.E., is a mechanical engineer at Taylor Engineering, LLC. He was a key member of the RP-1455 team and is a corresponding member of GPC-36.

Control Sequences &Controller ProgrammingController ProgrammingControllerBY MARK HYDEMAN, P.E., FELLOW MEMBER ASHRAE; STEVEN T. TAYLOR, P.E., FELLOW MEMBER ASHRAE; AND BRENT EUBANKS, P.E., ASSOCIATE MEMBER ASHRAE

Since the inception of direct of direct of digital control (DDC) systems, control system manu-facturers and their customers had to choose between two fundamentally different fundamentally different fundamentallyapproaches to control system programming:

• Configurable controllers, where control logic is

largely preprogrammed, allowing only a few configura-

tion points and setpoints to be adjusted by the user; and

• Fully programmable controllers, where users can pro-

gram whatever sequences they want into the controller.

Configurable controllers have several advantages:

the control logic and programming are pretested and

debugged, reducing installation and commissioning

time. These controllers are almost plug-and-play, with

only minor configuration work required. But configu-

rable controls developed the reputation of having overly

simplistic control logic that sometimes did not meet the

requirements of energy and indoor air quality standards.

Unfortunately, using fully programmable controllers

presents its own challenges. Even though many HVAC

applications are very similar, if not identical, there are

no industry standards for control sequences. This results

in the following problems and inefficiencies:

• Almost every application is treated uniquely, often

with custom logic that must be prepared and debugged

over and over again. The result is a waste of resources

and, because of the limited time devoted to system pro-

gramming and commissioning, systems that are never

fully debugged and free of operational problems.

• Control sequences are often poorly written or

incomplete. Writing precise, concise, and bug-free

sequences is difficult given the complexities of modern

HVAC systems and few engineers do it well. Installing

contractors are often left to complete or correct poorly

written sequences often without a complete under-

standing of the design intent.

• Control sequences mandated by energy efficiency

standards such as ASHRAE/IES Standard 90.1-2013,

Energy Standard for New Buildings Except Low-Rise Residen-

tial Buildings. and indoor air quality standards such as

ASHRAE Standard 62.1-2013, Ventilation for Acceptable

Indoor Air Quality. are not always implemented cor-

rectly due to lack of familiarity by design engineers

and DDC system programmers.

RP-1455 and Guideline 36


TECHNICAL FEATURE

• The commercial control system market is extremely

competitive, often resulting in insufficient time devoted

to system programming and commissioning, in part

because the custom nature of the programming for each

project is so time intensive.

• DDC systems are very powerful, yet their power

is not fully used by most engineers. For instance, few

systems are programmed with real-time diagnostic

algorithms to detect faults, yet almost all systems have

the hardware and software capability to do so. These

diagnostics could be used to detect system faults that

result in energy waste or failure to maintain process or

comfort conditions.

• Specified alarm logic varies from generating too few

alarms, allowing faults to occur without the knowledge

of building operators, to generating too many alarms

that quickly become ignored by building operators.

Hierarchical fault detection can be used to prevent nui-

sance alarms as described below.

Ideally, standardized high performance, optimized

sequences should be developed that can be prepro-

grammed into controllers, providing the benefits of con-

figurable controllers while not sacrificing performance.

Research Project 1455In 2008, Research Project 1455-RP1 was initiated to

develop “best of class” HVAC system control sequences.

This first phase included developing optimized control

sequences for air distribution and terminal subsystems

including single zone VAV AHUs, multiple-zone VAV

AHUs, and a variety of VAV terminal units, including sin-

gle-duct, dual-duct, and fan-powered. These sequences

were derived from controls specifications submitted by

research partners including engineering consultants,

government institutions, and academic researchers. As

such, they embody dozens of person-years of design and

commissioning experience. A second-phase research

project (discussed further below) is being developed to

address heating and cooling plants and hydronic distri-

bution systems.

These standardized advanced control sequences for

common HVAC applications will provide the following

benefits:

• Reduce engineering time for design engineers.

Rather than develop sequences themselves, they can

adapt standard sequences that have been proven to

perform.

• Reduce programming and commissioning time for

contractors.

• Reduce energy consumption by making systems less

dependent on proper implementation and commission-

ing of control sequences.

• Reduce energy consumption by ensuring that

proven, cost effective strategies, including those re-

quired by ASHRAE standards and building codes, are

fully implemented.

• Improve indoor air quality by insuring control

sequences are in compliance with IAQ standards and

codes such as Standard 62.1.

• Reduce energy consumption and reduce system

downtime by including diagnostic software to detect and

diagnose air handler faults and make operators aware of

them before they cause performance problems.

In addition to the written sequences, the RP-1455

deliverables include companion control schematics and

points lists for each of the systems. There are application

notes in the sequences that clarify the logic behind or

application of the written sequences.

As part of RP-1455, functional logic diagrams of the

sequences were created and they were programmed

into one manufacturer’s controllers and bench tested.

This both verified that the written sequences could be

programmed and that these sequences could be imple-

mented in commonly available commercial HVAC con-

troller hardware. A future research project (discussed

further below) will test the sequences in a real facility.

However, RP-1455 is based on control sequences that

have been proven in the field, so this process is expected

to help fine-tune the logic rather than lead to major

revisions. This project will also develop functional

performance tests to allow manufacturers to test their

implementation of the sequences to ensure they were

correctly programmed.

Guideline 36At the conclusion of RP-1455, ASHRAE Guideline 36,

“High Performance Sequences of Operation for HVAC

Systems” was created to publish and maintain these best

of class sequences and future best of class sequences

for other systems. The guideline committee will keep

the sequences up to date by evaluating and processing

recommendations for changes from users to improve

performance or fix bugs. The sequences will ultimately

be expanded to include sequences for heating and



cooling plant and hydronic systems,

dedicated outdoor air systems,

radiant heating and cooling sys-

tems, etc., whether developed from

research projects or recommended

by engineers, manufacturers, and

contractors. The committee will also

maintain functional performance

tests used by DDC manufacturers

and commissioning agents to verify

that sequences have been properly

programmed.

The latest version of Guideline 36,

as well as news, updates and sup-

porting material can be found at

the Guideline Project Committee

36 public website (http://gpc36.

savemyenergy.com/).Information on

how to join the committee is avail-

able for those who wish to become

formally involved in the process of

developing this Guideline.

Once the Guideline is published,

it is expected that design engineers

will be able to use them as the basis

of control for standard system con-

figurations. For standard systems, it

might be possible to simply include

in their specifications a table of

ASHRAE Guideline 36 sequences

with check boxes for the paragraph

numbers that are applicable to their

project. Having a standardized basis

for the sequences will reduce the

burden in writing control sequences

and improve the operation of those

sequences in the field. Controls

manufacturers are expected to pre-

program the sequences into their

controllers and verify the program-

ming is correct with factory per-

formed functional tests. Then con-

trol contractors can simply use the

programming directly with minimal

configuration. Commissioning work

could then consist simply of verify-

ing that configuration and setpoints

are correct; field functional testing

of programming using standardized

functional performance tests should

be less burdensome.

Status and Future WorkGuideline 36 will be issued

for an advisory public review

soon and is available for down-

load from the GPC-36 public

site. It will include the RP-1455

sequences as issued in the proj-

ect’s final report with slight modi-

fications (primarily clarifications

of language, plus a couple of

improvements to logic). The com-

ments received from this review

will be used to create a publica-

tion public review expected to be

issued late 2015 or early 2016.

The Guideline committee will also

adapt the work of future ASHRAE

research projects into the Guideline

as the work is completed. The fol-

lowing are active ASHRAE proj-

ects expected to be adapted into

Guideline 36 sequences in future

addenda:

• 1587-RP: “Control Loop Per-

formance Assessment.” Creates a

metric for determining if control

loops are tuned, designed to be

programmed into controllers for

real-time assessment of loops.

• 1746-TRP: “Validation of RP-

1455 Advanced Control Sequences

for HVAC Systems – Air Distribu-

tion and Terminal Systems.” Tests

RP-1455 sequences in real building

environment using formal function-

al tests to test stability and perfor-

mance.

• 1747-TRP: “Implementation of

RP-1547 CO2-based Demand Con-

trolled Ventilation for Multiple Zone

HVAC Systems in Direct Digital Sys-

tems.” Creates workable sequences



from the RP-1547 results, which is

a theoretical approach to Standard

62.1-based CO2 demand controlled

ventilation.

• 1711-WS: “Advanced Sequences

of Operation for HVAC Systems –

Phase II Central Plants and Hydronic

Systems.” The second phase of RP-

1455 that includes chilled water and

hot water plants and distribution

systems.

ConclusionsIt is expected that most DDC

system manufacturers will pre-

program the ASHRAE Guideline 36

sequences into their systems so that

they can be used directly or easily

adapted for most any HVAC system

application. Therefore, the plug-

and-play benefits of configurable

controllers are realized without

sacrificing energy performance and

occupant comfort.

Guideline 36 is expected to be

published in 2015 or early 2016.

But that should not prevent the

RP-1455 sequences from being

used right now. They are currently

available by downloading the

RP-1455 reports from the ASHRAE

website, or by downloading the

review draft of Guideline 36 at

http://gpc36.savemyenergy.com/.

Engineers can duplicate some or

all of the sequences in their con-

trol specifications. Manufacturers

should also start programming

the sequences into their systems

right now in anticipation of their

being specified by engineers and

to gain an advantage over their

competitors.

References1. Hydeman et al, Final Report ASHRAE

RP-1455 Advanced Control Sequences for HVAC Systems, Phase I, Jan. 14, 2014.


BUILDING AT A GLANCE

Brett Griffin, P.E., is vice president at Environmental Systems Design, Chicago.

BY BRETT GRIFFIN, P.E., MEMBER ASHRAE

The heart of the mechanical sys-tem for this data campus is thechiller plant. Due to aggressivespeed to market and flexibilityrequirements, the chiller plantwas designed to be modular andscalable to allow for the plant tobe stick built onsite or pre-builtoffsite.

Data CenterEconomizer Efficiency

HONORABLE MENTIONINDUSTRIAL FACILITIES OR PROCESSES, NEW


Digital Chicago Datacampus

Location: Franklin Park, Ill.

Owner: Digital Realty

Principal Use: Data Center

Includes: 80,000 ft2 data center white space (across seven suites); 16,000 ft2 office space; 64,000 ft2 electrical support space; 5,000 ft2 chiller plant

Gross Square Footage: 570,000 across three buildings

Conditioned Space Square Footage: 165,000 to date

Substantial Completion/Occupancy: Multiple phases. Phase 1 completed May 2013. Phase 2 completed January 2015.

Data center design has always been associated withwords like availability, reliability, and precision cool-ing. Although availability and availability and availability reliability remain reliability remain reliability critical,energy efficiency,energy efficiency,energy flexibility, scalability, speed to market,and cost effectiveness are driving modern driving modern driving data centerdesign. The Digital Chicago Datacampus took advantage took advantage tookof efficiencyof efficiencyof improvements efficiency improvements efficiency made possible by improved by improved byserver equipment thermal tolerances, which open upthe opportunity to opportunity to opportunity condition a data center space withoutmechanical cooling for cooling for cooling significant portions of the of the of year ina wide range of climates. of climates. of The campus also integrates theefficiency improvementsefficiency improvementsefficiency with the concepts of modular- of modular- ofity, repeatability, and speed to market. The result is afinal product that was not only reliable only reliable only and energy effi- energy effi- energycient, but also relatively simple relatively simple relatively to build, operate, main-tain, and expand.


ABOVE Phase 1 secured customer entrance.

LEFT Arial view of entire Datacampus site.

2015 ASHRAE TECHNOLOGY TECHNOLOGY AWARD CASE STUDIES

This facility is designed for multi-tenant data center

use with a master plan involving multiple buildings and

phases of construction on a single site. Phase 1A and

1B have been occupied for over a year and consisted of

redeveloping a 110,000 ft2 (10 220 m2) building into data

center space, electrical infrastructure, and flex office

space, as well as a new 5,000 ft2 (470 m2) water-cooled

chiller plant building that was pre-assembled off site.

Phase 2 was recently completed and consisted of two

15,000 ft2 (1 400 m2) data center suites with associ-

ated electrical support infrastructure located within

an adjacent 292,000 ft2 (21 130 m2)building. Each

phase is designed to be stand-alone, but also cross-

tied through the chilled water system for increased

flexibility and redundancy.

The master plan includes a new chilled water plant

for each phase of construction. However, the chilled

water distribution supporting Phase 1 was cross-tied to

support Phase 2 due to available capacity of the Phase 1

plant. Future phases will also take advantage of remain-

ing on-site chilled water capacity until the load requires

a new parallel chilled water plant to be installed.

The distribution piping is arranged in a 2N looped con-

figuration with connection points and isolation valves in

place to allow new chilled water plants to be installed and

fully commissioned without affecting the live loads of the

existing data centers. The site is ultimately designed to

accommodate over 577,000 gross square feet (52 950 m2)

of space, including 270,000 ft2 (25 085 m2) of white space

supporting 31.9 MW of data center IT load.

Mechanical Design OverviewThe mechanical system is designed to be concurrently

maintainable, modular, and scalable. Compared to

other similar size and type of systems it is also cost effec-

tive, energy efficient, and simple to operate.

The heart of the mechanical system is the chilled water

plant. It consists of water-cooled centrifugal chillers with

open loop cooling towers for heat rejection and plate and

frame heat exchangers for series (integrated) waterside

economization. The distribution design uses primary-sec-

ondary chilled water pumping and thermal and condenser

water storage for thermal ride-through and back-up.

All of the equipment and associated piping is concur-

rently maintainable and installed in a modular and

redundant manner such that each “line-up” of capacity

equipment (chiller, cooling tower, heat exchanger, con-

denser water pump, and primary chilled water pump) is

repeatable and can be installed in 12 ft (3.7 m2) wide by

40 ft (12.2 m2) long shipping containers, or field erected

on site, depending on schedule and site constraints.

The modular design is extremely important for this

project because of the sheer size of the site and magnitude

TABLE 1 Breakdown of mechanical system energy use in each mode of operation. In this application, the only variable affecting cooling load is the process load and the only variable affecting efficiency, other than percent load, is ambient wet-bulb. Excel was used for energy modeling.

KW/TON

FULL MECH. COOLING

PARTIAL ECONOMIZER

FULL ECONOMIZER

CT 0.037 0.037 0.019

CWP 0.061 0.070 0.061

CH 0.438 0.243 0.000

PCHWP 0.020 0.020 0.000

SCHWP 0.029 0.038 0.038

CRAH Units 0.127 0.127 0.127

Makeup Air Unit 0.073 0.004 0.073

Total Cooling System 0.784 0.539 0.318

% Hours Annually 7% 32% 61%

Annualized kW/ton 0.055 0.17 0.19


of the master planned infrastructure. It allows for scal-

ability and flexibility to fully use the site over time, giv-

ing ownership the opportunity to defer capital cost of

equipment and further improve speed to market for each

deliverable. This delivery model allows the owner to offer

a superior product at a cost-competitive rate.

The modular concept started with Phase 1 of this project.

The chilled water plant was manufactured off-site with

two chillers, pumps, cooling towers, and heat exchang-

ers initially (Phase 1A). The remaining equipment for

the Phase 1 plant was installed and commissioned later

when new leases were signed (Phase 1B). This concept was

taken advantage of again when the leasable white space

expanded into Phase 2 of the site.

Even though the design included a

new chilled water plant and new 2N

chilled water piping loop dedicated

to the Phase 2 spaces, sufficient avail-

able capacity remained on the Phase

1 chilled water plant, so the Phase 2

plant was deferred.

The total capacity of each chilled water plant is 2,400

tons at (N+1) redundancy and is dedicated to only the

critical cooling loads (data center and UPS rooms). The

site is designed for up to five identical 2,400 ton chilled

water plants. With over a year of operation under its

belt, the entire mechanical system operates on an aver-

age of 0.415 kW/ton annually with a mechanical partial

power utilization effectiveness (PUE) of 1.135 (Table 2).

This is in large part due to the extraordinarily high

number of economizer hours it has offered.

Energy Efficiency & Environmental ImpactThe term “economizer” refers to the mode of cool-

ing where there are no compressors operating (full

economizer) or when at least a portion of the cooling is

achieved without compressors (partial economizer). For

a waterside economizer, this means directly transferring

heat from a relatively warm fluid (chilled water return-

ing from the heat load) to a relatively cold fluid (con-

denser water leaving the cooling towers) and rejecting

this heat to the outdoors.

To optimize this mode of operation, three design fea-

tures were considered (listed in order of importance):

elevating the “warm” fluid temperatures (chilled water

supply and return), reducing the “cold” fluid tempera-

ture (condenser water supply), and minimizing the heat

transfer losses through cooling towers, heat exchangers,

and cooling coils.

What determines the setpoint of the chilled water sup-

ply temperature is the maximum allowable air tempera-

ture entering the servers (cold aisle temperature). This

design value was guided by the published guidelines

in the ASHRAE Datacom Series of books and was set at

70°F (21°C) dry-bulb with a minimum dew point of 40°F

(4.5°C). This allowed the chilled water system to supply

between 60°F (15.5°C) and 63°F (17°C) chilled water. With

a tight approach temperature across the heat exchangers

and oversized cooling towers, the plant is allowed to oper-

ate in full economizer mode whenever the ambient wet-

bulb temperature is below 52°F (11°C)

(61% of time).

The integrated economizer was fur-

ther optimized by carefully selecting

the right cooling coils, control valves,

and secondary chilled water pumps

to allow for a constant 17°F chilled

water DT at all loads, resulting in a chilled water return

temperature of 77°F (25°C). This allows the plant to

operate in partial economizer mode with ambient con-

ditions at or below 68°F (20°C) wet bulb (93% of time).

Full mechanical cooling is required only 7% of the time.

See Figure 1.

This system is designed to operate in economizer

mode at all load conditions. This is especially important

because most data centers operate at part load for the

majority of their life time, but are usually only optimized

for their peak load performance. Currently, over 5,000

tons of chilled water CRAH unit capacity are online,

operating under automatic temperature control (N+2

in every suite and UPS rooms), with only a combined

chilled water load of less than 750 tons (15% load to coil

capacity ratio). By contrast, at this low load, most sys-

tems would supply much more chilled water flow than

required, resulting in more pumping horsepower than

necessary and a very low chilled water return tempera-

ture (low DT syndrome), virtually eliminating any ben-

efit of partial economizer operation.

After 17 months of operation (across two full sum-

mers) and a constant load of less than the capacity of one

chiller, the chillers only have a total of 4,419 runtime

hours combined (from BAS trending). This is only 35%

of the total hours across this span and also includes all

the hours of start-up and commissioning, validating and

TABLE 2 Annual partial PUE. Partial PUE is IT load plus mechanical load, divided by IT load.

ENERGY USAGE ANNUAL VALUE

IT Load (kWh) 64,561,200

Mechanical Loads (kWh) 8,724,960

Partial PUE 1.135



FIGURE 3 Simplified chilled water flow diagram—full mechanical cooling mode.

Open (Typ.)

90°F CT-2

CH-1

On (Typ.)

77.5°F

0

Off

CHWR=77.5°F

OpenP-4

P-3

CWS ≥ 75°F

Open

77.5°F

CH-2

60°F 60°F

condenser water supply temperature is greater than the

chilled water return temperature by an offset of 2.5°F

(1.38°C) (7% of year). See Figure 3.

2. The plant operates in partial economizer mode when

the condenser water supply temperature is between the

chilled water supply temperature setpoint of 60°F (15.5°C)

and 3°F (1.4°C) below the chilled water return tempera-

ture of 77°F (25°C)(32% of year). (Only two valves change

exceeding the design calculations of operating at least

61% of time on full economizer, even at minimum load.

In addition, because all of the CRAH units are able

to operate together in parallel with such low loads, the

fans are all operating at their minimum speeds at a frac-

tion of the energy of the same fans at full speed. Figure

2 highlights some of the design fea-

tures that allow this system to oper-

ate so efficiently and take advantage

of these economizer hours at all load

conditions.

Operation and MaintenanceThe chiller plant control system

is simple and reliable. All of the

equipment and piping is concur-

rently maintainable. The control

of the central chilled water plant

is achieved through three simple

sequences. (The only variable affect-

ing operational modes is system

water temperature, not flow or load

or ambient conditions.)

1. The plant operates in 100%

mechanical cooling mode when the

CT-1

P-1

HX-1

FIGURE 2 Simplified schematic heat rejection flow diagram.

95°F1

IT Equipment

26

65°F

CRAH Unit 60°FSCHWP

CWP

77.5°F3

5

CT58°F

HX CH4

7

PCHWP

95°F1

IT Equipment

26

65°F

CRAH Unit 60°FSCHWP

CWP

77.5°F3

5

CT58°F

HX CH4

7

PCHWP

1

23

4

5

67

Space return air temperature elevated to 95°F DB. CRAH unit fans are controlled to modulate to maintain this temperature at all loads.

CRAH unit cooling coils are selected at high chilled water DT and low approach temperature to ADP (5°F).

CRAH units are equipped with pressure independent control valves to maintain design chilled water DT (17°F) and highest return chilled water temperature at all loads (77°F).

HX located in hot secondary chilled water return and immediately downstream of cooling towers to exchange heat between the hottest indoor fluid and the coldest outdoor fluid. HX sized for low approach (2.5°F) with design flow, lower at reduced flow.

Sized for low approach (5°F at design WB). CT piped in header and designed to allow partial flow rate to allow operators to run in running redundancy mode to save tower fan energy. Energy model does not assume running redundancy, however, CT leaving condenser water setpoint is 58°F year-round for simple control and optimum economizer hours. When ambient WB is above 52°F the fans will naturally run at 100% fan speed to make the coldest water possible. When below 52°F the fans will slow down to maintain temperature.

CRAH units operate in running redundancy for simple controls and fan energy savings.

HX located on secondary loop so PCHWPs can turn off during full economizer.

¯

¯¯

¯

¯

¯¯

FIGURE 1 Bin hours for Chicago’s O’Hare airport (top) and data center chiller plant modes of operation (bottom).

0

0

00

0 0 0

72

9

89 164 1443

22555

744672

725648

394

341

539

192

579

585

617

519

665744

15100

800

700

600

500

400

300

200

100

0 Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sept. Oct. Nov. Dec.

Bin

Hour

s

19

CWP OPERATING MODE ANNUAL HOURS % OF HOURS

Mechanical Cooling 654 7%

Partial Economizer 2,787 32%Full Economizer 5,319 61%

0 0 09

100% Mechanical Cooling Partial Economizer 100% Economizer



position based on two temperature

measurements, independent of load

and flow.) See Figure 4.

3. The plant operates in 100%

economizer mode when the con-

denser water supply temperature is

at or below the chilled water sup-

ply temperature setpoint of 60°F

(15.5°C) (61% of year). (Only two

valves change position based on one

temperature measurement and one

setpoint, again independent of load

and flow.) See Figure 5.

As stated previously, the secondary

chilled water return temperature

remains constant at all ambient and

load conditions. The cooling tower

fans operate with a single condenser

water supply temperature setpoint

year-round, meaning that above

52°F (11°C) ambient wet-bulb the

fans operate at 100% speed, and they

modulate when the ambient wet-

bulb is below (52°F °C) (61% of year).

The condenser water pumps and pri-

mary chilled water pumps operate at

constant speed when enabled, and

the secondary chilled water pumps

modulate to maintain constant

chilled water system differential

pressure.

Lastly, the ventilation system pro-

viding code minimum ventilation,

pressurization, and makeup air

for the battery exhaust is handled

through small dedicated makeup air

units (MAUs) with packaged controls.

FIGURE 4 Simplified chilled water flow diagram—partial economizer cooling mode.

Cost EffectivenessThis system is unique to the owner because it uses a

central cooling plant for multiple data center suites.

Until now, central plants were considered cost and

schedule prohibitive as they required too much up-front

capital and longer construction schedules than systems

that use mostly manufactured unitary products such as

air-cooled chillers, DX split systems, and rooftop units.

Finally, during the design phase, the project team

worked with the local utility company through their

local utility rebate program. The requirements of the

program are to compare the installed mechanical cool-

ing system to a baseline mechanical cooling system

established by the utility company and verify the sav-

ings through a strict Measurement and Verification

plan, also established by the utility company. At $0.07/

kWh, the overall savings would be approximately

$325,000 per year for Phase 1 alone.

Open (Typ.)

CT-2

CH-1

60°F < CHWR <77°F (Typ.)

P-2

CHWR=77.5°F

ClosedP-4

P-3

60°F ≤ CWS < 75°F

CH-2

60°F 60°F

CT-1

P-1

HX-1

Closed

FIGURE 5 Simplified chilled water flow diagram—full economizer cooling mode.

Closed/Bypass(Typ.)

CT-2

CH-1

P-2

CHWR=77.5°F

ClosedP-4

P-3

CWS < 60°F

CH-2

CT-1

P-1

HX-1

Closed

Off(Typ.)

CHWS=60°F


Solving Low Delta T

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COLUMN DATA CENTERS

Donald L. Beaty

Donald L. Beaty, P.E., is president and David Quirk, P.E., is vice president of DLB AssociatesConsulting Engineers, in Eatontown, N.J. Beaty is publications chair and Quirk is the chair of ASHRAE TC 9.9.

BY DONALD L. BEATY, P.E., FELLOW ASHRAE; DAVID QUIRK, P.E., MEMBER ASHRAE

Are Data Centers Data Centers Data Drying Up? Drying Up? DryingValuable new data new data new on the relationship between humidity and humidity and humidity electrostatic discharge(ESD) in a data center environment has recently been recently been recently published through ASHRAEResearch Project RP-1499. The relationship between ESD and humidity has humidity has humidity long been long been longanecdotally known,anecdotally known,anecdotally but insufficiently quantified. insufficiently quantified. insufficiently

Everyone has had the experience of walking on a car-

pet and touching a metal surface soon afterwards – the

result is an electrostatic shock.

The voltage of the shock ranges from a couple hun-

dred volts to many thousand volts, and if the item being

touched is sensitive electronics, there is a potential to

damage that equipment. Likewise, these shocks tend to

have much greater frequency (and magnitude) in the

winter when the humidity is lower than in the summer

when the humidity is higher.

Historical Trends in Data Center Humidification IT equipment manufacturers have long known that

electrostatic discharges occur at low relative humidity

levels, and that these discharges can cause IT equipment

failures. Legacy data centers were designed with a nar-

row relative humidity deadband: 45-55% RH.

When ASHRAE TC 9.9 first published Thermal

Guidelines for Data Processing Environments in 2004, the

recommended RH was a little more relaxed to the

range of 40% to 55% RH, but introduced an Allowable

Range that was set at a much broader 20% to 80%.

In the second edition of Thermal Guidelines (2008), the

recommended humidity level was further relaxed to

5.5°C (42°F) dew point on the low side, and the lower of

60% RH and 15°C (59°F) dew point on the high side. Figure

1 plots the 2004 and 2008 recommended envelopes on a

psychrometric chart. The allowable range stayed the same

between the first and second editions, at 20% to 80% RH

and is plotted on a psychrometric chart in Figure 2.

In the latest (third) edition of the Thermal Guidelines,

published in 2012, the recommended range has stayed

the same, but two additional allowable ranges have been

added: A3 and A4 (Figure 3). Both of these ranges allow

for as little as 8% RH on the low side.

Justification for Additional ResearchHumidification can have a significant impact on

energy consumption that extends beyond the simple

consumption of the humidification conditioning equip-

ment itself. For instance, a high minimum humidity

requirement in conjunction with an air-side economizer

could result in blocking out a significant number of

economizer hours and associated energy savings. Due

to the significant impact of high minimum-humidity

threshold requirements on energy consumption of data

centers, ASHRAE TC 9.9 applied and received approval

from ASHRAE for a research project to better under-

stand the correlation between humidity levels and ESD.

The Research ProjectWhile it may seem like a fairly straightforward

research project, the actual implementation of a study

to correlate ESD with humidity is complex. Part of

the setup for the research involved obtaining a better

understanding of exactly what mechanisms occur to

create these discharges.

For instance, a person walking will definitely build up

a charge (and the charging process was also studied in

this report), but how will this be discharged? Will the

person discharge by touching a piece of IT equipment

with their hand, or will contact be made by first touch-

ing the equipment with something metallic, such as a

flash drive? The magnitude and duration of these dis-

charges will be different, and both instances were tested

as part of the research.

The type of shoe worn by the occupant matters as does

the type of flooring. At the least granular level, one can

New Research on Humidity and its Impact on Electrostatic Discharge


COLUMN DATA CENTERS

classify shoes as ESD dissipative or non-ESD dissipative,

and the floor as ESD dissipative or non-ESD dissipative.

This study went into far more detail. For instance, 11

different shoe types were investigated and a total of 13

types of floors were also investigated (see Table 1 for the

full list).

Finally, a total of four relative humidity levels were

examined: 60%, 35%, 15%, and (as an added require-

ment) 8%. While 8% RH may seem excessively low, as

mentioned earlier, two new environmental classes

of IT equipment (A3 and A4) were added as Thermal

Guidelines environmental classes in the middle of this

research project, and TC 9.9 was able to obtain ASHRAE

approval for the scope of the research to be extended

from 15% RH down to 8% RH.

ESD in Real Life vs. Research SimulationIn real life, ESD can cause:

• Self-correcting errors (such as a lost package in LAN

traffic);

• An upset that may need user intervention; or

• Actual physical damage to IT equipment.

under environmental condition B.” If one has empirical

data on the ESD failure rate at one relative humidity, the

results of the study allow one to estimate the change in

For research purposes,

measurements of these

failure modes were not spe-

cifically documented, as the

robustness of specific mod-

els of equipment varies so

widely. Rather, voltages and

durations were measured,

and these were compared

to the industry standard

voltages (4kV and 8kV)

defined in the International

Electrotechnical

Commission document IEC

61000-4-2.

Rather than absolute values,

the report generally provides

data in terms of relative prob-

abilities of harmful events.

This strategy is similar to the

x-factor that is defined in

Thermal Guidelines.

The value of the x-factor is a ratio, defined as the

“Number of equipment failures under environmental

condition A divided by Number of equipment failures

FIGURE 2 2004 and 2008 allowable ranges.

Relative Humidity90% 80% 70% 60% 50% 40% 30%

80

75

70

65

60

55

50

45403530 20 100

Dew-

Point

Tem

pera

ture

°F

Wet-Bu

lb Tem

peratu

re °F

80

75

70

65

60

55

50

4540

35

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120

Dry-Bulb Temperature °F

Recommended

20%

10%

SOUR

CE: A

SHRA

E. M

ODIF

IED

BY D

LB

ASHRAE 2004/2008 – Class 2 Allowable

ASHRAE 2004/2008 – Class 1 Allowable

SOUR

CE: A

SHRA

E. M

ODIF

IED

BY D

LB

80 90% 80%

70%

60%

55%

50%

40%

30%

20%

10%

Wet-Bu

lb Tem

peratu

re °F

75

70

65

60

50

55

45 50 55 60 65 70 75 80 85Dry-Bulb Temperature °F

2004

200880%

60%

40%20%

FIGURE 1 2004 and 2008 recommended ranges.


a “well-defined pattern” (WDP) as

shown in Figure 4, and a “random

walking experiment” (Random).

People, however, are not the only

generators of electrostatic charge in

data centers. Equipment carts are

one additional source of charge, and

cabling is another.

ResultsThe results of the study fall into sev-

eral categories; this brief article cannot

do justice to the results, but the follow-

ing can be considered a summary.

For evaluating the combined

impact of flooring and footwear in

a data center, the six categories of

data centers examined are shown in

Table 2.

One takeaway from this data is that

the probability of the 4000 Volt and

8000 Volt discharges vary by up to

18 orders of magnitude based on the

type of floors and footwear. These

construction and operations variables

can decrease ESD impact without any

impact on energy consumption.

It should be noted that the

experimental results listed in Table

2 involved walking. Additional

experiments, involving standing

up from an office chair, and taking

off a sweater, were able to generate

higher voltages in humans.

ConclusionsThe research provided sev-

eral conclusions, including the

following:

• Reducing the relative humidity

in a space will increase the voltages

of ESD.

• Reducing the absolute humid-

ity (dew-point temperature) does

not always lead to an increase in

voltages, but the threshold at which

a reversal may occur is low - in the

range of -10°C to 0°C (14°F to 32°F).

• The chair and sweater events

caused very high voltages.

TABLE 1 Floor and shoe test conditions. ©IBM

LOW RH EFFECTS ON DATA CENTER OPERATION

TEST CONDITIONS

FLOOR SHOES

3M 4530 Asia 3M China Slip On

3M 6432 Cond 3M Full Sole

3M 8413 Running Shoe

3M Green Diss DESCO 2 Meg Sole

3M Low Diss DESCO Heel

3M Thin VPI DESCO Full Sole 2 Meg

Epoxy 1A Hush Puppy

Flexco Rubber Red Wing

HPLF Stata Rest

HPLN Sperry

Korean Vinyl Heel Strap

Standard Tile

Wax

FIGURE 3 2012 allowable ranges.

Relative Humidity90% 80% 70% 60% 50% 40% 30%

80

75

70

65

60

55

50

45403530 20 100

Dew-

Point

Tem

pera

ture

°F

Wet-Bu

lb Tem

peratu

re °F

80

75

70

65

60

55

50

4540

35

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120

Dry-Bulb Temperature °F

Recommended

A1

A2

A3 A4

20%

10%

SOUR

CE: A

SHRA

E. M

ODIF

IED

BY D

LB

ESD failure rate at another rel-

ative humidity level, all other

factors being equal.

Generating the ChargeBefore a potentially damag-

ing discharge can occur, an

electrostatic discharge first

has to build up. A signifi-

cant portion of the research

was aimed at understanding

these phenomena, since a

significant discharge cannot

be discharged if a charge has

not built up in the first place.

The testing procedures were

generally in compliance with

IEC 61000-4-2, as mentioned

earlier.

For human charging experi-

ments, another standard,

ANSI/ESD STM97.2, defines

• A factor called Relative Humid-

ity Voltage (RHV) can be used to

express the increase in the average

voltages if the humidity is de-

COLUMN DATA CENTERS

www.info.hotims.com/54426-39www.info.hotims.com/54426-34


creased. For a decrease in relative humidity from 45%

to 8%, the RHV is approximately 3. For a decrease in

relative humidity from 25% to 8%, the RHV is approxi-

mately 1.5.

The RHV would need to be considered in combination

with the relative scale of voltages commonly occurring

in a given environment (based on the combinations of

flooring, shoes, etc.) and the frequency that ESD events

occur based on data center specific operations in order

to determine the complete picture of ESD risks to elec-

tronic equipment failures.

RecommendationsThe study provides general recommendations in a

number of areas. These can probably best be categorized

into the areas of relative humidity levels, flooring and

footwear, grounding, chair and carts, grounding proce-

dures, and cabling.

• For relative humidity levels, the results clearly show

that the lower RH levels create higher discharge voltages

and a higher frequency and potential for development

of higher voltages. In most cases, however, these voltages

are less than the threshold voltages that IT equipment is

FIGURE 4 Well-defined pattern.

Groundable Point A

Right FootStart/End

4

3

21

5

Left FootStart/End 6

Groundable Point B

COLUMN DATA CENTERS



designed to withstand, especially if ESD precautions are

taken.

• Using ESD-mitigating flooring and footwear, the

risk of ESD upset and damage can be reduced to an

insignificant level, even if the humidity is allowed

to drop to low values, such as 8%. Unfortunately,

controlling the footwear in most data centers is very

impractical.

• All office chairs and carts selected for use in data

centers should have ESD-mitigating properties.

TABLE 2 Summary data in probability for voltages greater than a threshold value (based on fitted lines).

TYPE OF DATA CENTER 500 VOLT D ISCHARGE PROBAB ILITY 4,000 VOLT D ISCHARGE PROBAB ILITY 8,000 VOLT D ISCHARGE PROBAB ILITY

15% RH & 59°F 50% RH & 80°F 15% RH & 59°F 50% RH & 80°F 15% RH & 59°F 50% RH & 80°F

No Static Control 18% 0.2% 0.5% 3.7 × 10–6 % 0.1% 3.2 × 10–8 %

Dissipative Floors, Dissipative Footwear 16% 19% 0.016% 1.0 × 10–4 % 5.5 × 10–5 %, 2.2 × 10–7 %

Dissipative Floors, Uncontrolled Footwear 34% 5.65% 0.9% 0.001% 0.09% 2.3 × 10–5 %

Conductive Floors, Dissipative Footwear 0.003% 1.6 × 10–7 % 1.8 × 10–7 % 1.8 × 10–11 % 7.4 × 10–9 % 8.9 × 10–13 %

Conductive Floors, Uncontrolled Footwear 8% 0.1% 0.004% 4.7 × 10–10 % 4.1 × 10–5 % 7.5 × 10–13 %

Conductive Rubber Floors, Uncontrolled Footwear 0.1% 9.6 × 10–13 % 8.6 × 10–7 % 1.4 × 10–20 % 1.6 × 10–8 % 3.5 × 10–23 %

• Also grounding straps should be used when before

making contact to any of the sensitive electronics.

• A standard set of ESD-mitigation procedures listed

here will ensure a very low ESD incident rate at all hu-

midity levels tested.

• For the new ASHRAE A3 and A4 environmental

classes, the authors conclude that there is a greater

chance for ESD events, but indicate that this can be

mitigated with proper data center design and good ESD

prevention with operating procedures. In general, the

COLUMN DATA CENTERS



damaging ESD events, however, is

quite interdependent with other

variables in the data center, such

as floor conductance and operating

procedures.

There are many industry “best

practices” and risk mitigation meth-

ods that could be used to avoid dam-

aging ESD on sensitive electronics.

Oftentimes, these mitigation meth-

ods can be hard to implement and

enforce, but especially in light of the

data collected in this project, they

are proven means to reducing the

risks associated with ESD.

The new ESD research has helped

to quantify the ESD risks associated

with lower level humidity levels in

the data center, and has concur-

rently shown other approaches to

mitigating damage to IT equipment

from ESD events. This research pro-

vides guidance for the operation of

data centers in the new ASHRAE A3

and A4 environmental conditions.

It also provides an excellent set of

technical data that could form the

basis for adjustments to ASHRAE’s

recommended and allowable envi-

ronmental ranges for IT equipment

in the future.

For More InformationFor those interested in the details

of this study, the RP-1499 research

project has spawned a wealth of

Technical Papers, as well as a final

report. An initial paper (DE-13-031)

was published in 2013. The recent

2015 Winter Conference in Chicago

increased risk in migrating from 25% RH to 8% RH is

about a 50% increase in the incidence of ESD risk.

Closing CommentsLower relative humidity generally increases both

the frequency and magnitude of ESD discharges.

Whether these increases actually increase the risk

included three more papers, CH-15-005, CH-15-006,

and CH-15-007. These papers can be obtained from the

ASHRAE Bookstore.

References1. IEC 6100-4-2 Electromagnetic Compatibility (EMC) – Part 4-2:

Testing and measurement techniques – Electrostatic discharge im-munity test.

COLUMN DATA CENTERS

A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 8 A S H R A E J O U R N A L a sh r a e . o r g M A R C H 2 0 1 57 8

BUILDING AT A GLANCE

Art Sutherland is president of Accent Refrigeration Systems in Victoria, BC, Canada.

Energy EfficientIce Rink

FIRST PLACEPUBLIC ASSEMBLY, NEW

The Westhills Recreation

Centre’s outdoor rink offers

an interesting energy bal-

ance opportunity in winter by

providing additional rejected

energy during the heating sea-

son. Even with the extensive

use of energy, 60% of waste heat

is pumped to a nearby housing

development.


BY ART SUTHERLAND, MEMBER ASHRAE

Westhills Recreation Centre

Location: Langford, BC, Canada

Owner: City of Langford, BC, Canada

Principal Use: Recreation center

Includes: Ice skating, bowling, restaurant, commercial offices

Employees/Occupants: 50 employees and 1,200 maximum occupancy in all areas

Gross Square Footage: 75,000

Conditioned Space Square Footage: 75,000

Substantial Completion/Occupancy: September 2012

Occupancy: 100%

An extensive study conducted study conducted study by Natural by Natural by ResourcesCanada determined that a typical 40,000 ft2 (3716 m2) icerink in Canada will consume an average of 1.5 of 1.5 of million kWhof equivalentof equivalentof energy per energy per energy year. The Westhills RecreationCentre in Langford, British Columbia, is nearly twice nearly twice nearly asbig usesbig usesbig only 768,000 only 768,000 only kWh. And, the refrigeration systemfor the ice surfaces produces so much waste heat thatexcess is shared with a nearby housing nearby housing nearby development. housing development. housing

The 75,000 ft2 (6967 m2) facility consists of an of an of NHL sizeindoor ice rink, an outdoor ice rink and a skating trail skating trail skating join-ing theing theing two rinks together. The facility also facility also facility houses a 20lane bowling alley, bowling alley, bowling restaurant/lounge, party rooms party rooms party and10,000 ft2 (929 m2) of leased of leased of office space with multiplesport-related tenants. The total cost of construction of construction of was$13.5 million, with a $9 million grant from the BuildingCanada Fund.


ABOVE Westhills Recreation Centre’s NHL size indoor ice rink.

LEFT VFD-driven high efficient ammonia compressors provide refrigeration for the ice rinks in winter and building air conditioning in summer.

2015 ASHRAE TECHNOLOGY TECHNOLOGY AWARD CASE STUDIES

The outdoor ice rink was designed with embedded

refrigeration piping for winter ice and water fixtures to

convert it into a children’s splash park in summer, making

use of the same footprint for both summer and winter.

Eliminating Fossil FuelsThe city of Langford, located on Vancouver Island, has

among the highest natural gas prices in North America.

The project objective was to eliminate natural gas con-

sumption for all heating, hot water and dehumidifica-

tion loads while minimizing electrical consumption

year-round. In fact, the building does not use fossil

fuels at all except in the kitchen, which does use natu-

ral gas. And, it was determined during the preliminary

design phase that the quantity of heat rejected from the

refrigeration to service the three ice surfaces would be

more than enough to satisfy all of the heating loads with

extra heat that could be shared with a nearby housing

community.

The challenge was to ensure that there was heat avail-

able between compressor run cycles and during the

colder periods of the year when the refrigeration was

running less. The outdoor ice rink offered an interesting

energy balance opportunity in Langford’s mild winter by

providing additional waste heat during the peak heating

season, just when it was needed most.

To ensure that there would be no periods between

refrigeration run cycles without heat being available, two

approaches where taken. The refrigeration compressors

and brine pumps were equipped with variable speed

drives. The variable speed drives, controlled by the com-

puter control system, were programmed to operate the

compressors at their lowest permissible speed while pre-

cisely maintaining the temperature setpoint.

This strategy provided a number of benefits. The com-

pressors always operated at their maximum coefficient of

performance (COP) due to the higher saturated suction

temperatures and lower saturated condensing tempera-

tures while running at low speeds. The centrifugal brine

pumps were also modulating their speed and taking

advantage of the Pump Affinity Law, resulting in reduced

electrical consumption. The main objective of perpetuat-

ing the heating cycle was also met as the compressor run

cycles were much longer throughout the day.

A system also had to be designed that would have heat

available during colder periods and when the night set

back control strategy would shut the compressors off. To

achieve this, we required some form of thermal storage.

A cost effective solution was to use the ice rink sub-floor

heating system for thermal storage.

Traditionally, ice rink sub-floor heating systems would

operate at 40°F (4.5°C) to prevent frost heaves caused by

long-term refrigeration operation. To minimize any

impact to the ice surface as a result of higher sub-floor

temperatures, we installed 6 in. (150 mm) of R-5 insula-

tion board between the ice pad and the heating floor,

and around the outside walls. This enabled the tempera-

ture of the sub-floor to be increased to 75°F (24°C). This

“geothermal system on steroids” was cost effective to con-

struct because the civil work, piping mains, pumps and

half the insulation would have been required anyway for a

traditional sub-floor heating system.

During the winter, 100% of the refrigeration waste

heat is harvested with an energy recovery condenser,

which is able to provide 82°F (28°C) glycol temperature

while maintaining 85°F (30°C) condensing tempera-

ture. The warm 82°F (28°C) glycol from the energy

recovery condenser directly provides radiant heating

throughout 19,000 ft2 (1765 m2) of public space.

The concrete floors are maintained at 72°F to 74°F

(22°C to 24°C), which provides an excellent level of

comfort. In mid-winter, an energy recovery heat pump



the energy recovery loop as the heat source. During the

winter, the hot water is produced at a COP of 4.28 (4.02

adjusted for pump horsepower).

The ice rink desiccant dehumidifier was custom

designed for this facility (Figure 1). It uses a low tem-

perature desiccant rotor that can be regenerated at

125°F (52°C), versus the traditional gas-fired rotors

that require 275°F (135°C). The system uses two coils in

will boost the glycol temperature from 95°F

(35°C) to 105°F (40°C), as required, to main-

tain comfort in all areas.

There are 15 HVAC units and two HRVs

interspersed throughout the complex. All of

the air handlers have large close-approach

coils designed to provide heating with 95°F

(35°C) glycol and cooling with 50°F (10°C)

glycol. In very cold months, the heating glycol

temperatures will automatically reset to pro-

vide sufficient heat.

With the combination of long compressor

run times and thermal storage, the building

heat pumps have an uninterrupted energy

source of 75°F (24°C) and supply 95°F (35°C)

FIGURE 1 Energy recovery dehumidifier with cooling coil that services the ice rink.

heating glycol, while operating with an exceptional COP

of 7.97 (7.49 adjusted for pump horsepower).

Domestic hot water for the facility is provided through

two stages. The first stage is free heat from the ammo-

nia desuperheating system and ranges from 100°F to

120°F (38°C to 49°C). The water is then brought up to

140°F (60°C) using a hot water heat pump that also uses

Low Grade Heat 70° to 80°F

Free HeatPump

React In

Dry Air To Rink

Cooling Pump

Chiller Return

Humid Air From Rink

React Out React Pump

Post Heat Pump

Medium Grade Heat 125°F

T

T

T

T

T T

T

T




series to regenerate the desiccant wheel. The first coil is

circuited for the 82°F (28°C) glycol that is directly har-

vested from the ammonia condenser and can temper

the air up to 70°F (21°C). The second coil obtains its heat

from an energy recovery heat pump, which also harvests

heat from the ammonia system and produces 130°F

(54°C) glycol to provide the finished temperature to

regenerate the desiccant wheel.

On a typical 40°F (4°C) winter day the result of this

two-step temperature lift is that the first 35% of the tem-

perature lift is done using free heat and the second 65%

by using a heat pump with a COP of 4.99 (4.68 adjusted

for pump horsepower). The low temperature regenera-

tion results in an air temperature entering the rink in

the 85°F (29°C) range rather than the 115°F (29°C) range,

which is typical of the gas-fired units.

A post-heating coil is installed that uses energy from

the heat pumps to provide comfort heating above the ice

rink bleachers, if required.

As a result of these initiatives, no fossil fuels are used

in the facility other than the use of natural gas in the

kitchen since the complex was commissioned in 2012.

Improving Electrical Energy EfficiencyAnother challenge was keeping electrical consumption

(electricity is provided by hydroelectricity) in check

while using heat pumps in lieu of natural gas. The

primary refrigerant is ammonia, which is inherently

efficient. We used a new model of ultra-high efficient

VFD-driven compressors that handle both the ice rink

duty in winter and the air-conditioning duty in sum-

mer. The compressors have a cooling COP of 4.62 dur-

ing the ice season and a summertime air conditioning

COP of 15.1. The VFD uneven parallel compressors have

a range of 30 to 60 tons (106 to 211 kW) for the small

compressor and 60 to 90 tons (211 to 317 kW) for the

large compressor, allowing them to exactly track the

refrigeration load year-round. With 100% of the energy

being recovered, the compressors have a combined

heat/cool COP of 10.2 in winter. All of the loads in the

complex including fans, pumps and compressors have

a VFD controlled by the building automation system to

minimize energy consumption.

During the summer, the hot water heat pumps extract

heat from the 19,000 ft2 (1765 m2) of radiant floors,




taking advantage of both sides of the heat pump cycle,

which boosts the total heat pump COP to 7.6.

The ice rink will remove 8,000 pounds of snow per

day during normal ice maintenance. When melted in

the snow melt pit, this snow will provide 1,152,000 Btus

(96 ton-hours) of useful cooling that helps shave the

peak off the air conditioning requirement. A submersed

enhanced surface coil is used to extract the energy dur-

ing peak air conditioning hours. The coil has the ability

to deliver 325,000 Btu/h (95 258 kW) of glycol at 45°F

(7°C). This heat transfer can be sustained for three to

four hours per day, depending on how much snow is in

the pit.

Figure 2 shows where the harvested heat was used

within the Westhills ice rink during a single 24 hour

period in October 2012. The facility heating require-

ment was fairly low and the ice rink dehumidification

was fairly high. The outdoor rink was not in operation

so we were not at full waste energy production. The

percentages were calculated from the run times on the

three building heat pumps and run times on the various

distribution pumps, along with the average supply and

return temperatures. This was just a snapshot in time

so the dynamic heating requirements for each load will

change day to day with the various user groups, outdoor

ambient temperature and humidity.

Community Energy SharingEven with the extensive use of energy, only 40% of the

waste energy is required within the complex. Therefore,

FIGURE 2 Ice rink energy use on a typical fall day.

Snow MeltUnderfloor HeatZamboni Hot Water

Building Hot WaterRadiant HeatHVAC Heating

DehumidificationFresh Air VentilationHeat Sent to Housing

56%

3%

13%

6% 3%

5%4%

6%

4%




once the on-site geothermal field is satisfied and all of

the zones are within their programed range, the remain-

ing 60% of the heat is transferred via a VFD-driven

pump to a growing housing development 400 yd (366 m)

away as an energy source for the household heat pumps.

The VFD is temperature controlled and programmed

to maintain the ice rink energy loop at 80°F (27°C). A

brazed plate heat exchanger provides a fluid separation

between the housing development energy loop and the

ice rink energy loop. There are just under 500 homes in

the housing development, so the waste energy is only

able to provide a portion of the required heating energy

in winter. This results in absolutely every bit of waste

energy being used from the two ice surfaces and skat-

ing path during the winter. This scenario is much easier

to control in comparison to a situation where there

is too much heat that must be diverted to an outdoor

TABLE 2 Payback for the energy efficiency features, including energy sharing.

Annual Reduction in Natural Gas Consumption $46,928.96

BC Hydro’s Calculated 259,751 kWh Annual Savings with VFDs $15,585.00

Refrigeration and Air Conditioning Energy Efficiency Improvements $5,718.00

Total On-Site Energy Savings $68,231.96

Off-Site Energy Value Sent to Housing Development $41,470.00

Total Energy Savings $109,701.96

Net Cost Over Conventional System $308,988.00

Payback on Energy Efficiency Components 2.81 Years

TABLE 1 Electrical consumption for the Westhills Recreation Complex.

MONTH KILOWATT HOURS B I LLED COST

January 2014 111,070 $7,478.26

February 2014 104,304 $7,084.41

March 2014 91,074 $6,060.16

April 2014 94,609 $5,563.04

May 2014 75,168 $6,095.84

June 2014 62,157 $4,087.19

July 2014 56,600 $3,827.70

7 Month Total 594,982 $40,196.60

Actual Meter Reading Credit 146,850 $10,272.17

Actual Energy Consumed 448,132 $29,924.00

Monthly Average 64,016 $4,274.92

Extrapolated to 1 year 768,192 Annually $51,294.04




condenser. The average value of the approximately

830,000 kWh of energy sent to the housing development

if it were natural gas would be $41,470.

The balance of heat in the housing development is

supplied by two 180 ton (633 kW) VFD-driven ammo-

nia heat pumps that use a geothermal field below a

soccer field as the energy source.

The ammonia heat pumps are only required in the

winter and operate at COPs ranging from 8 to 15. The

heat pumps maintain the housing energy loop at a con-

stant 60°F (16°C), which results in favorable COPs for the

household heat pumps.

Water and Sewage ReductionDuring the 8 months of the year

that all of the energy is being used,

the evaporative condenser is not

used, which results in an annual

water reduction of approximately

750,000 gallons (2.8 L) per year.

Electricity UseTable 1 summarizes BC Hydro’s elec-

trical consumption for the Westhills

Recreation Complex, including the

refrigeration and air conditioning

plant and all of the heat pumps, air

handlers, energy distribution pumps

and lighting. The ice rink refrigera-

tion system provides all heating and

cooling, dehumidification and hot

water for the entire 75,000 ft2 (6967

m2) complex, including the ice rink,

the 15,000 ft2 (1394 m2) of rented

office space and shop area, the res-

taurant and the bowling alley.

Almost every ice rink in North

America would have two energy

sources being consumed simultane-

ously, including electrical for the ice

plant, lighting, HVAC, etc., and fossil

fuels for hot water, dehumidification,

building heating, etc.

The electrical consumption for the

Westhills ice rink is much lower than

a typical single 40,000 ft2 (3716 m2)

ice rink, and this modest amount

of energy is serving an indoor and

outdoor rink with a skating trail, in

addition to providing all of the heat-

ing, air conditioning, hot water and

dehumidification requirement for a

75,000 ft2 facility (6967 m2).




PRODUCTS

PRODUCT SHOWPLACETo receive FREE info on the

products in this section, visit

the Web address listed below

each item or go to

www.ashrae.org/freeinfo.

A Control Valves With ThermostatSpartan Peripheral Devices, Vaudreuil, QC,

Canada, offers a line of control valve pack-

ages with the company’s TE150 dual-output

modulating proportional plus integral (P+I)

room thermostat. The direct- or reverse-

acting devices feature internal or external

sensors and auto changeover input.


Water HeatersMagnaTherm boiler/volume water heaters

from LAARS, Rochester, N.H., provide 95%

thermal efficiency and 5:1 turndown. The

boiler features the company’s VARI-PRIME

pump control, which seamlessly matches

boiler firing rate to pump flow.


B Commercial Fume HoodThe new Model GRRS Fire-Ready Hood

from Greenheck, Schofield, Wis., functions

as a standard ventilation range hood with

the added capacity to suppress stove-top

fires. This helps to protect residential-style

appliances used in commercial settings.


Unit HeatersTrane, Davidson, N.C., has upgraded and ex-

panded the Expanse line of gas unit heaters.

The heaters feature a tubular heat exchang-

er, designed to be more reliable and effi-

cient than the conventional clamshell style.


BAS Control SystemThe ECLYPSE Connected System Controller

from Distech Controls, Brossard, QC,

Canada, is a modular and scalable platform

providing BACnet/IP, wired and wireless

IP connectivity. The system consists of a

control automation and connectivity server,

power supplies, and I/O modules.


A

Control Valves With ThermostatBy Spartan Peripheral Devices

B

Commercial Fume HoodBy Greenheck

Energy Management SystemThe Specified Comfort Energy Management System from Specified Controls, Indianapolis, is an integrated energy management system that enables multiple thermostats, lighting and load sensors, meters, fans and outlets to be wirelessly networked. www.info.hotims.com/54426-156


compact pipe covering fora safe and quick assembly for housing gas pipes, watercondensation discharge hoses and power lines.

Uponor’s PEX-a Pipe Support provides continu-ous support of PEX pipe for suspended piping applica-tions, enabling hanger spac-ing similar to copper or steelpipe. The 9-ft (2.7 m) support channels are available in arange of sizes and come with nylon-coated, stainless-steelstrapping to secure the pipe to the support.

SharkBite’s 2XL fittings are suitable for plumbing andhydronic heating applica-tions. These fittings combinecopper, CPVC, and PEX pipe in any combination withoutany tools, soldering, clamps, unions or glue. A range oftees, elbows and couplings are available.

PumpsKadant Johnson’s Liqui-

Mover condensate pump isan efficient way to pump or lift liquids and is availablewith either a float or float-free level control.

The Wilo Helix Excel is a vertical multistage pumpused in pressure boosting applications. Designed as apump-system, the hydrau-lics, mechanicals, controls

and electrical were designed and developed to fit together,eliminating any losses from using off-the-shelfcomponents.

Refrigeration/Process CoolingRefrigerant Solutions

Limited announced RS-70, a new GWP drop-in replace-ment refrigerant for R-22, designed to have the lowestpossible GWP with similar cooling capacity and coef-ficient of performance (COP) as R-22.

DunAn Microstaq, Inc.’s silQfloTM Silicon Servo Valveis a MEMS technology based microvalve suited for microand macro cooling applica-tions. It is an electronicallycontrolled proportional expansion device for lowcapacity cooling applications. For high capacity coolingapplications, it is a pilot valve.

Sensors, InstrumentsHoffman Controls offers

ECM Controllers in three models for controllingup to 16 ECM condenser fan motors from a singlecontroller.

Superior Signal Companyannounces the third Generation AccuTrak VPEleak detector. Featuring new internal circuitry and greatersensitivity, the detector is suitable for steam traps,

Left photo: A lively brazing demonstration taking place at the TurboTorch booth,. Right photo: (L-R) Kazuyuki Tamura, Tophio Sawada, and Takeshi Kobato examine the Z-Vent positive pressure approved piping from Z-Flex.

valve, and bearing wear applications.

The MaxiBlue reservoir sensor from Blue DiamondPumps offers an alterna-tive to stuck or sunken floatswitches that only run when condensate is produced. Itis suitable for environments that are both demandingand expensive to access for maintenance.

QTI Sensing Solutions developed the QTSSP andQTIP68 temperature sensor lines to avoid sensor failureduring the freeze/thaw cycles in refrigeration equipment.These waterproof sensors provide the reliability neededto overcome the temperature swings and moisture thatthermal cycles create.

The ThermoPro SeriesTP10 from Spire Metering Technology uses ultrasonictechnology to accurately measure temperature andflow. The clamp-on trans-ducers make installationsimple with no risk of leaking or contamination.

The Delta Controls eZNS-T100 network sensor com-bines temperature with humidity, CO2 and motionoptions into a single pack-age. The sensor features alow profile design, NFC com-munications, and LCD andcapacitive touch buttons.

The Sensaphone Sentinel

is a 12-channel remote moni-tor available with an optionalcellular modem for operation in locations where telephoneor internet service is unob-tainable. The unit allowsusers to monitor conditions such as temperature, humid-ity and water detection and receive alarms via phone,text and e-mail.

SniffIT X3® from Nolek isa handheld battery powered refrigerant leak detector. Thesmallest detectable levels of refrigerants with this detec-tor is 0.017 oz/year.

The HMS-1655 fume hoodmonitor from Triatek fea-tures a touchscreen with boldgraphics and menus. The home screen displays sashheight, face velocity, hood status, flow, temperature,time, and date. The product uses a closed-loop system tobetter regulate air entering and exiting the fume hood,and communicates with a face velocity flow sensor andsash position sensor to pro-duce truer fume hood read-ings with a higher degree of reliability.

Software, Mobile AppsFieldpiece Instruments

launches a new app, JobLink™, for wireless real- time measurements on iOSdevices. The app allows techs to view live measurements,

Products, From Page 13


SHOW COVERAGE

get insightful diagnostics, create professional lookingreports, and email findings to the office and customer.

Aquanomix introduces its new Symphony™ intel-ligent water quality and effi-ciency software system thatbridges currently separate building management dataof cooling tower water qual-ity and energy efficiency.The aggregated data of key performance indicators iscalculated into a single num-ber representing the overallefficiency of a cooling system called the Nexus Number™.

LUDECA’s tab@lign is a tab-let-based solution for pump-motor alignment which combines the PRÜFTECHNIKlaser measurement technol-ogy with tablet and smart-phone devices.

The Enceptia FabricationValue Pack is a set of add-on utilities to boost productivityand out-of-the-box capabili-ties with Autodesk fabrica-tion software. The Imperial Configuration Pack includespre-configured settings, templates and reports. ThePipe Rack Calculator aids pipe-hanger design and FabSync makes changing local and network settings easy.

Tune-Rite™ from Bacharach is an on-demandHVAC software program that helps contractors makemore thorough and efficient

for bonding a wide variety of insulation to galvanizedmetal substrates. It has the added benefit of having agreen label—requiring no explosion proof rooms—witha special non-flammable propellant, combined withextremely low VOC.

The Acrefine API-M typemodular rubber pad is designed to minimize vibra-tion and noise transmission from HVAC equipment tostructures. The pads can be cut to custom sizes eas-ily with a box knife and the through-bolt hole in eachmodule allows for easy installation. Applicationsinclude floor mounted mechanical equipment thatgenerate high frequency vibration like pumps, chill-ers, compressors, centrifugal fans, blower-coil units, ventsets, and low pressure pack-aged air-handling units.

service calls. It watches the analysis in real-time to deter-mine if the heating system being evaluated is operating in acceptable parameters and provides customized on-screen recommendations for tuning the system for opti-mum performance.

Firestone Building Products Company offers the “Build My Wall” app for metal and cavity wall sys-tems. The app is a searchable database of compatible wall panels and systems where users can view 3D renderings and obtain technical, instal-lation and fastening details.

Tools and AccessoriesMilwaukee Tool’s Black

Iron Press Jaws and Rings were designed for use on Viega MegaPress fittings. They provide a faster alter-native to threading and roll grooving to connect Schedule 5-40 Black Iron Pipe.

Klein’s Switch Drive Handle System allows users to alternate between a power tool and hand tool, mini-mizing the number of tools and saving space. The quick release mechanism secures any driver with a 0.25 in. (6.35 mm) hex shaft to con-vert an impact rated acces-sory to a powerful hand tool.

Carlisle HVAC Products offers the Non-Flam Travel-Tack, an aerosol adhesive

Valves, ActuatorsBray Commercial Division

launches the AutoTouchTerminal (ATT) line of pres-sure independent controlvalves. These valves fea-ture three point floatingand modulating actuators with and without failsafeprotection.

NitroVue Flow Indicatorfrom Uniweld Products features an easy to read flowindicator label and an adjust-able valve gives control overthe low flow of nitrogen gas during the brazing of coppertubing in AC and refrigera-tion systems.

HCi offers the TerminatorPICV (PressureIndependent Control Valve) for HVAC temperature con-trol. It is a combination, field adjustable, automatic balancevalve, and a full authority, equal percentage, tempera-ture control valve.

Left photo: Steven Cho (right) of EasyFlex looks on as Henry Gross (left) inspects some flexible pipe. Right photo: Product engineer Lennart Stahl (left forground) discusses thefeatures of Daikin’s VRF units with Paul Tseng.

Helge Jorgenson (left) and Ejner Kobbero (right) admire a 100-ton centrifugal chiller by Smardt Chiller Group.

A S H R A E J o u R n A l a sh r a e . o r g M A R C H 2 0 1 59 4

CLASSIFIEDS

BUSINESS OPPORTUNITIES

ADIABATIC AIR INLET COOLING

EcoMESH Adiabatic Systems Ltd.

www.ecomesh.eu

EcoMESH Benefits

ADIABATIC AIR INLET COOLING


www.ecomesh.eu

EcoMESH Benefits

ADIBATIC AIR INLET COOLING


www.ecomesh.eu

EcoMESH Benefits


www.ecomesh.euEcoMESH Adiabatic Systems Ltd.

www.ecomesh.euEcoMESH Adiabatic Systems Ltd.

www.ecomesh.eu

(1) (2) (3)

(4) (5) (6)

•Increased Capacity•Self Cleaning Filter•Shading Benefit

•No Water Treatment•Longer Compressor Life

•Increased Capacity•Self Cleaning Filter•Shading Benefit


•Reduced Running Cost•Reduced Maintenance

•Easy Retrofit•Improved Reliability•Increased Capacity•Self Cleaning Filter•Shading Benefit


Before After

•Reduced Running Cost•Reduced Maintenance

•Easy Retrofit•Improved Reliability•Increased Capacity•Self Cleaning Filter•Shading Benefit


EcoMESH Benefits

Before After

StandardInstallation

EcoMESHAddition

WaterSpray

CoolerAir Intake

•Reduced Running Cost

•Reduced Maintenance

•Easy Retrofit

•Improved Reliability

•Increased Capacity

•Self Cleaning Filter

•Shading Benefit

•No Water Treatment

•Longer Compressor Life

•Self Cleaning Filter

•Shading Benefit

•No Water Treatment

•Longer Compressor Life

Improving the performance of Air Cooled Chillers, Dry Coolers and Condensersand Refrigeration Plants. EcoMESH is a unique mesh and water spray systemthat improves performance, reduces energy consumption, eliminates highambient problems, is virtually maintenance free and can payback in one coolingseason.

Improving the performance of Air Cooled Chillers, Dry Coolers and Condensersand Refrigeration Plants. EcoMESH is a unique mesh and water spray systemthat improves performance, reduces energy consumption, eliminates highambient problems, is virtually maintenance free and can payback in one coolingseason.

Improving the performance of Air Cooled Chillers, Dry Coolers andCondensers and Refrigeration Plants. EcoMESH is a unique mesh andwater spray system that improves performance, reduces energyconsumption, eliminates high ambient problems, is virtually maintenancefree and can payback in one cooling season.

FREE COOLING BENEFITSFREE COOLING BENEFITS

PASSIVE COOLINGPASSIVE COOLING

PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net

FREE COOLING BENEFITSFREE COOLING BENEFITS

THERMAL ENERGY STORAGETHERMAL ENERGY STORAGE

..PCM ProductsPCM Productswww.pcmproducts.netwww.pcmproducts.net

BENEFITSBENEFITS


THERMAL ENERGY STORAGETHERMAL ENERGY STORAGEPhase Change Materials between 8ºC(47ºF) and 89ºC(192ºF)release thermal energy during the phase change which releaseslarge amounts of energy) in the form

of latent heat. It bridges the gap between

energy availability and energy use and

load shifting

capability.

• EASY RETROFIT•LOW RUNNING COST• REDUCED MACHINERY• INCREASED CAPACITY

•GREEN SOLUTION• REDUCED MAINTENANCE• FLEXIBLE SYSTEM•STAND-BY CAPACITY

• No Running Cost

• Maintenance Free

• Cost Effective

• Easy Retrofit

• No Moving Parts

• Green Solution

+8ºC(47ºF)

+27ºC(80ºF)

• 15~25% Power Saving


• Quick Payback

• Easy Retrofit

• Running Cost Saving

• Stand-by / Back-up

Thermal Energy Storage (TES) is the temporary storage of coldenergy for later use. It bridges the gap between energy availabilityand energy use.

EutecticTES within thecold store can beCharged using theexcess capacity duringoff-peak periods / over-night ambientconditions to shift the peak loads.

Eutectic TES is astatic system offering a full

stand-by capability in case of anymechanical failures and a

maintenance free back-up facility.

Thermal Energy Storage (TES) is the temporary storage ofthermal energy for later use, bridging the gap betweenenergy availability andenergy use.

Using conventionalsolar collectors one canprovide an under floorlow grade heating

utilising +27ºC (81ºF)Phase Change Material(PCM) containers andeliminate the for anyother heating source.PCM energy storageoffer energy / fuel freeheating solution.

PCMModules

Over-night cool energy is stored in the form of +20ºC (68ºF)Phase Change Material (PCM) containers and later the storedenergy is utilised to absorb the internal and solar heat gainsduring day-time for an energy free passive cooling / load shiftingsystem.

TubeICE

+20~24ºC(68~75ºF)

• No Running Cost


• Cost Effective

• Easy Retrofit

• No Moving Parts

• Green Solution

(1) (2) (3)

(4) (5) (6)

Phase Change Materials between +8~20ºC(47~68ºF)can be simply charged using a free cooler over-night without theuse of a chiller and later the stored FREE energy can be used tohandle the day-time sensible

building loads.

•REDUCED MAINTENANCE

• FLEXIBLE SYSTEM

•STAND-BY CAPACITY

• LOWER INSTALLATION COST

• SIGNIFICANT ENERY SAVING

• GREEN SOLUTION

+13ºC(55ºF)

Over-night cool energy is stored in the form of +27ºC (80ºF)Phase Change Material (PCM) containers and later the storedenergy is utilised to absorb the internal and solar heat gainsduring day-time for an energy free passive cooling system.

•Easy Retrofit

•Heating even after sunset

•Uniform heating over 24h

•Flexible solution

•Simple control

•Cost effective solution

•Energy free solution

•Running cost savings



FREE COOLING BENEFITSFREE COOLING BENEFITSFREE SOLAR HEATINGFREE SOLAR HEATING

..



ENERGY STORAGE BENEFITSENERGY STORAGE BENEFITS

COLD STORAGE LOAD SHIFTINGCOLD STORAGE LOAD SHIFTING

www.pcmproducts.netwww.pcmproducts.net

Cells

FOR RENT

HVAC ENGINEERSAll levels. JR Walters Resources, Inc., specializing in the placement of technical professionals in the E & A field. Openings nationwide. Address: P. O. Box 617, St. Joseph, MI 49085-0617. Phone 269-925-3940. E-mail: [email protected]. Visit our web site at www.jrwalters.com.

OPENINGS

Classified line advertisementsare inserted in 7-point type at the

rate of $12.00 per line or frac-

tion thereof, includes heading and

address. Six words to the line average.

Maximum insertion 15 lines. Prices

are net. Available Engineer insertions

up to 60 words for members are $6.00

per line.

Classified Column Inch Border Advertisements are inserted in 8-point bold heading

and address type of 7-point body

type at the rate of $115.00 per

column inch or fraction thereof,

includes heading and address. Maxi-

mum length 5 inches. Maximum width

2-1/8”. Prices are net. Available

Engineer insertions for members

are $55.00 per column inch.

Classif ieds are accepted in the

categories of Job Opportunities,

Rentals, Business Opportunities, and

Software.

Closing date:Copy must be received by the clas-

sified department by the 3rd of the

month preceding date of issue.

Address: Send request for further

information to:

ASHRAE JOURNAL

Vanessa Johnson

1791 Tullie Circle NE

Atlanta, GA 30329

Phone 678-539-1166

Fax 678-539-2166

E-mail: [email protected]

RATE SCHEDULE:

To place an ad contact: Vanessa Johnson Advertising Production & Operations Coordinator

1791 Tullie Circle NE | Atlanta, GA 30329Phone: 678-539-1166 | Fax: 678-539-2166 Email: [email protected]

ASHRAE Journal Classified Ads

The Foremost Medium for Reaching Engineering Professionals

Classified ads are

ALWAYS productive.

M A R C H 2 0 1 5 a sh r a e . o r g A S H R A E J o u R n A l 9 5

SOFTWARE

www.bcatech.comwww.bcatech.com 407407--659659--06530653

For All HVAC Products Selection Pricing / Configuration Submittals Parts Customer Support

More...

Everything Your Reps Need… ...to increase sales

[email protected], www.4mbim.com, www.4msa.com

mep

The power of BIM for MEP design•Calculations directly from the BIM model•Automatic generation of all the case study results •Automatic generation of the final set of drawings (plan views, vertical diagrams, axonometric diagrams, Piping/Ducting Networks in 2D and 3D and others) •Complete documen-tation of results (detailed calculation sheets, Technical Reports, Bill of Materials and many more) •IFC import/export to ensure collabora-tion with other BIM applications.

FineHVAC - HVAC Design HVAC Loads (Ashrae 2013), Chilled and Hot Water piping, Airduct Sizing, Psychrometric Analysis (includes also design for Merchant and Naval Surface Ships - Ashrae ch. 13.1 & 13.3).

FineFIRE - Fire Fighting Design NFPA 13 fully calculated systems for tree, gridded or looped systems (includes also EN 12845, BS 9251, FM, CEA 4001 & AS 2118 regulations)

FineSANI - Plumbing Design Water supply and Sewerage design

FineELEC - Electrical Design

FineGAS - Gas Network Design

FineLIFT - Elevator Design

ASHRAE Journal Classified AdsThe Foremost Medium for Reaching Engineering Professionals

To place an ad contact: Vanessa Johnson

Advertising Production & Operations Coordinator

1791 Tullie Circle NEAtlanta, GA 30329

Phone: 678-539-1166Fax: 678-539-2166

Email: [email protected]


ADVERTISING SALESASHRAE JOURNAL

1791 Tullie Circle NE | Atlanta, GA 30329 (404) 636-8400 | Fax: (678) 539-2174

www.ashrae.orgGreg Martin | [email protected]

Associate Publisher, ASHRAE Media Advertising Vanessa Johnson | [email protected]

Advertising Production Coordinator

NORTHEASTNelson & Miller Associates – Denis O’Malley; Jack O’Malley5 Hillandale Ave., Suite 101Stamford, CT 06902(203) 356-9694 | Fax (203) [email protected]

SOUTHEASTMillennium Media, Inc. – 590 Hickory Flat RoadAlpharetta, GA 30004Doug Fix (770) 740-2078 | Fax (678) 405-3327Lori Gernand (281) 855-0470 | Fax (281) [email protected]; [email protected]

EASTERN CANADANelson & Miller Associates – Denis O’Malley; Jack O’Malley5 Hillandale Ave., Suite 101Stamford, CT 06902(203) 356-9694 | Fax (203) [email protected]

OHIO VALLEYLaRich & Associates – Tom Lasch512 East Washington St.Chagrin Falls, OH [email protected](440) 247-1060 | Fax (440) 247-1068

MIDWESTKingwill Company – Baird Kingwill; Jim Kingwill664 Milwaukee Avenue, Suite 201Prospect Heights, IL 60070(847) 537-9196 | Fax (847) [email protected]; [email protected]

SOUTHWESTLindenberger & Associates, Inc. – Gary Lindenberger; Lori Gernand7007 Winding Walk Drive, Suite 100 Houston, TX 77095(281) 855-0470 | Fax (281) [email protected]; [email protected]

WESTLaRich & Associates – Nick LaRich, Tom Lasch512 East Washington St.Chagrin Falls, OH [email protected]@larichadv.com(440) 247-1060 | Fax (440) 247-1068

KOREAYJP & Valued Media Co., Ltd – YongJin ParkKwang-il Building #905, Dadong-gil 5 Jung-gu, Seoul 100-170, Korea+82-2 3789-6888 | Fax: +82-2 [email protected]

CHINA, HONG KONG & TAIWANChina Business Media – Sean Xiao6-310 Xinchao No.162 Liaoyuan RoadFuzhou, Fujian, China86 186 5099 [email protected]

INTERNATIONALSteve Comstock(404) 636-8400 | [email protected]

RECRUITMENT ADVERTISING AND REPRINTSASHRAE – Greg Martin(678) 539-1174 | [email protected]

Advertisers Index/Reader Service InformationTwo fast and easy ways to get additional information on

products & services in this issue:

1. Visit the Web address below the advertiser’s name for the ad in this issue.2. Go to www.ashrae.org/freeinfo to search for products by category or company name. Plus, link directly to advertisers’ Web sites or request information by e-mail, fax or mail.

Company PageWeb Address



*Regional

AAON, Inc .........................................................29info.hotims.com/54426-2

Aerionics, Inc./Macurco .................................85info.hotims.com/54426-3

AHR Expo Orlando 2016 .................................91info.hotims.com/54426-55

Air-Conditioning, Heating, and Refrigeration Institute ............................................................61info.hotims.com/54426-4

A-J Mfg Co. Inc ...............................................80info.hotims.com/54426-5

ASHRAE Webcast ...........................................87info.hotims.com/54426-1

ASHRAE District Guides ................................54info.hotims.com/54426-60

*ASHRAE Hospitals.........................................53info.hotims.com/54426-61

Belimo Aircontrols USA ..................................71info.hotims.com/54426-6

British Columbia Institute of Technology ...54info.hotims.com/54426-7

Captiveaire .......................................................43info.hotims.com/54426-8

Captiveaire .......................................................11info.hotims.com/54426-9

Carrier Corp......................................................67info.hotims.com/54426-10

Chil-Pak ............................................................46info.hotims.com/54426-11

ClimaCool Corp. ...............................................15info.hotims.com/54426-12

Climaveneta S.p.A. ..........................................83info.hotims.com/54426-13

Daikin North America LLC ............... 2nd Cvr-1info.hotims.com/54426-14

Data Aire .....................................................24-25info.hotims.com/54426-15

Distech Controls ..............................................69info.hotims.com/54426-16

Dwyer Instruments .........................................60info.hotims.com/54426-17

EBTRON ...................................................3rd Cvrinfo.hotims.com/54426-18

Goodway Technologies ...................................37info.hotims.com/54426-20

Greentrol Automation Inc. .............................55info.hotims.com/54426-19

Heat Pipe Technology Inc ..............................12info.hotims.com/54426-21

ISIB....................................................................89info.hotims.com/54426-22

LTG Incorporated .............................................37info.hotims.com/54426-23

Messe Frankfurt-ISH China ..........................63info.hotims.com/54426-57

Mestek/KN Series ...........................................23info.hotims.com/54426-24

Mestek/RBI Water Heaters .............................9info.hotims.com/54426-25

Mestek/Xcelon ................................................51info.hotims.com/54426-26

METALAIRE ......................................................19info.hotims.com/54426-27

Metraflex ..........................................................38info.hotims.com/54426-28

*Mitsubishi Electric Sales Canada, Inc ......53info.hotims.com/54426-50

Munters Corp ..........................................4th Cvrinfo.hotims.com/54426-29

Munters Corp ...................................................21info.hotims.com/54426-30

Nexus Valve ......................................................76info.hotims.com/54426-31

Onicon, Inc .......................................................86info.hotims.com/54426-32

Ontrol .................................................................46info.hotims.com/54426-33

Parker Boiler Co. .............................................75info.hotims.com/54426-34

Performance Aire ............................................56info.hotims.com/54426-35

Petra Engineering ...........................................57info.hotims.com/54426-36

Pittsburgh Corning ..........................................10info.hotims.com/54426-56

Reliable Controls ...............................................2info.hotims.com/54426-37

Renewaire, LLC ................................................77info.hotims.com/54426-38

Rotor Source, Inc. ...........................................75info.hotims.com/54426-39

Rotronic Instrument Corp ..............................84info.hotims.com/54426-40

Schneider Electric ............................................5info.hotims.com/54426-41

Shortridge Instruments Inc ...........................56info.hotims.com/54426-42

Soler & Palau USA, Inc ..................................88info.hotims.com/54426-53

Southland Industries ......................................62info.hotims.com/54426-43

Specific Systems .............................................82info.hotims.com/54426-44

Taco....................................................................81info.hotims.com/54426-51

Taco....................................................................33info.hotims.com/54426-52

Tate Access Floors, Inc ..................................93info.hotims.com/54426-45

Tekleen Automatic Filters Inc .......................13info.hotims.com/54426-46

Thybar Corp ......................................................13info.hotims.com/54426-47

Titus ...................................................................41info.hotims.com/54426-58

Trane ..................................................................31info.hotims.com/54426-48

Unilux Advanced Mfg, LLC.............................32info.hotims.com/54426-49

EBTRON, Inc. |1663 HWY 701 S., Loris, S.C. 29569 | Internet: EBTRON.com | Phone: 800 2 EBTRON | email: [email protected]

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