Indoor Thermal Environmental Control and Satisfaction...standards (ASHRAE Std. 55, ISO Std. 7730)...

CENTER FOR THE BUILT ENVIRONMENT JULY 2014 UNIVERSITÀ IUAV DI VENEZIA 3 July 2014

Indoor Thermal Environmental Control and Satisfaction:

Advanced HVAC systems and occupant satisfaction and comfort

Fred Bauman Project Scientist Center for the Built Environment University of California Berkeley, CA USA

CENTER FOR THE BUILT ENVIRONMENT JULY 2014

Presentation overview

1. CBE organization and research areas

2. Brief history of early pre-CBE comfort research at UC Berkeley

3. Task-ambient conditioning and UFAD systems

4. Personal comfort systems

5. Radiant systems


CBE organization

Building science laboratory founded at UC Berkeley in 1980

CBE established in 1997 with support and oversight from the U.S. National Science Foundation

Industry Advisory Board sponsors and guides the research agenda

Semi-annual conferences in April and October emphasize collaboration, shared goals, and problem solving


Making a difference: Industry/University Collaboration

• Center for the Built Environment (CBE) • Originally established in 1997 as an NSF Industry / University

Collaborative Research Center (I/UCRC) Mission: To improve the design, operation, and environmental quality of buildings by providing timely, unbiased information on building technologies, evaluation tools, and design techniques

• Architects • Engineering • Contractors • Manufacturers • Utilities • Government agencies • Building owners

www.cbe.berkeley.edu


CBE Industry Advisory Board (38 members)

Architects

EHDD Architecture

Perkins+Will

Yost Grube Hall Architecture

WRNS Studio

ZGF Architects

Architects/Engineers

DIALOG

HGA Architects and Engineers

HOK

LPA Inc.

RTKL Associates

SOM

Contractors

DPR Construction

Swinerton Builders

Webcor Builders

Engineers

Affiliated Engineers, Inc.

Arup

Atelier Ten

Buro Happold

Charles M. Salter Assoc.

CPP

Integral Group

P2S Engineering

Southland Industries

Syska Hennessy Group

Taylor Engineering

WSP

Government Agencies

California Energy Commission

U.S. Department of Defense

U.S. General Services Admin.

Manufacturers

Armstrong World Industries

BASF Corporation

Big Ass Fans

Google, Inc.

Price Industries

REHAU

Utilities

Pacific Gas & Electric

San Diego Gas & Electric

Southern California Edison


CBE research team

Faculty Prof. Edward Arens, PhD Prof. Gail Brager, PhD Prof. Stefano Schiavon, PhD

Project Scientists, Research Specialists, Professional Researchers Fred Bauman, PE Darryl Dickerhoff Tyler Hoyt Paul Raftery, PhD Tom Webster, PE Yongchao Zhai, PhD Hui Zhang, PhD

Students/Visitors ~ 15-20 Graduate Student Researchers ~ 5-10 Visiting Scholars

Partner Relations/Communications David Lehrer

Program Administrator Jessica Uhl

UC Berkeley Collaboration Faculty and student researchers from architecture, engineering, business, computer science.


CBE visiting scholars program

CBE accepts visiting scholars at any level

•

• University faculty

• Building industry professionals

Submit application, including CV and description of research topic you would like to study while at CBE.

• Proposed topic must be related to ongoing research at CBE

Priority given to scholars who can stay for at least 12 months

CBE does not provide major financial support for visitors

For additional details, please see:

http://cbe.berkeley.edu/aboutus/visiting-scholars.htm






CBE research areas

1. Advanced Integrated Systems

Underfloor Air Distribution (UFAD)

Radiant Systems

Displacement Ventilation

Personal Comfort Systems

Natural Ventilation / Mixed-Mode

Energy Simulation Tool Development

2. Envelope Systems

Operable Windows and Thermal Comfort

Mixed-Mode Buildings

High-Performance Facade Case Studies

Measuring Facade and Perimeter Zone Performance


CBE research areas, continued

3. Indoor Environmental Quality (IEQ)

Occupant IEQ Survey Research

Advanced Thermal Comfort Model

Acoustical Performance

4. Controls and Information Technology

Wireless Lighting Controls

Demand Response (DR) Enabling Technologies

Building Energy Visualization

5. Standards and Guidelines

Adaptive Comfort Model

Air Movement Standards

Performance Measurement (PMP)

ASHRAE UFAD Design Guide


Comfort: part of Indoor Environmental Quality (IEQ)

Thermal comfort Lighting / visual comfort

Indoor air quality Acoustics


30-year costs of a commercial building

Personnel 92%

6%

2%

Operations & Maintenance

Capital costs

Why is IEQ important? (Hint: follow the $$)


Typical office building costs in $/sf per year

Why is IEQ important? (Hint: follow the $$)

Annually, people costs are 2 orders of magnitude more than energy costs


ASHRAE Standard 55 comfort zones

In practice (summer) Narrow zone: ~ 71 – 75°F

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

Comfort zone represents acceptable conditions for 80% of the people

Based on laboratory studies

-size-

Energy intensive: broad application of narrow setpoints


ASHRAE Research Project RP-462

In 1985-86, UC Berkeley (pre-CBE) conducted a field study of 10 office buildings in the San Francisco Bay Area.

We took detailed physical measurements at each workstation that we visited (2,342) using a portable thermal environment measurement system.

During the same visit, we surveyed the occupant to obtain their subjective responses using a portable laptop computer (pre-internet).

We analyzed the data to determine if current comfort standards (ASHRAE Std. 55, ISO Std. 7730) were being met.


1st of it’s kind! (1985)

New & improved (1990)

UFAD Commissioning

(2006)

Wireless with real-time monitoring

(2012)

Environmental measurements: Air temperature, radiant temperature, humidity, air movement, light levels


Results from RP-462 (McIntyre vote)

Despite being largely maintained within ASHRAE Standard 55 thermal comfort zone, 60% of occupants wanted “no change”, while 20% wanted “warmer” and 20% wanted “cooler” conditions.

CENTER FOR THE BUILT ENVIRONMENT JULY 2014 17

Thermal comfort

Traditional approach

• Satisfy up to 80% of building occupants by maintaining thermal environment within comfort zone (based on laboratory studies)

Personal control approach

• Allow personal control of the local thermal environment

satisfy up to 100% of occupants reduce occupant complaints

• Existing fan-driven supply outlets provide sizable range of temperature control: desktop ~ 13°F (7°C)


Personal Environmental Module (PEM)

• Around 1990, Johnson Controls developed the PEM to control (1) airflow (volume and temperature), (2) radiant heater, (3) sound masking, (4) task lighting, and (5) operation with occupancy sensor.

• UC Berkeley conducted field study (1996-97) that showed 100% satisfaction with thermal comfort when occupant used PEM.


Research begins on underfloor air distribution (UFAD)

Task-ambient conditioning (TAC) systems, such as the PEM, showed promise in the lab and field, but adoption by the building industry was very limited.

The TAC devices were considered to be too expensive and too complicated for widespread use.

UC Berkeley was looking for a technology that was more practical (less expensive and less complicated) that could provide improved comfort (with personal control), improved energy performance, and other advantages.

We began a long and large research effort to help develop


Basics: Overhead (OH) vs. UFAD

15-18°C (60-65°F) supply temp.

13-14°C (55-57°F) supply temp.

CENTER FOR THE BUILT ENVIRONMENT JULY 2014 21

Potential UFAD benefits

Improved occupant comfort, productivity and health

Improved ventilation efficiency and indoor air quality

Reduced energy use

Reduced life-cycle building costs

Improved flexibility for building services

Reduced floor-to-floor height in new construction


Underfloor air distribution (UFAD)

Multi-year, multi-faceted project began in early 1990s, as UFAD systems were being adopted

CBE became UFAD research leader, through simulations, lab, and field research

Developed advanced understanding of benefits and limitations (and dispelled myths)

Created numerous resources for designers, manufacturers, owners and operators

0

2

4

6

8

10

72 74 76 78 80

Ro

om

He

igh

t [f

t]

Temperature [°F]

η=0 η=0.38 η=0.65 η=0.81


Design practice • Lack of familiarity

•

•previous experience

Design tools and guidelines • No standardized design guidelines

• No UFAD design tools, only conventional tools

Research • Gaps in fundamental research

o Room air stratification

o Underfloor plenum performance

o Whole-building energy simulations


UFAD deliverables

UFAD Technology Website (2000)

ASHRAE Design Guide (2003)

EnergyPlus simulation capability,

Cooling Load Design Tool (2010)

Extensive technology transfer through workshops, journal papers, and articles

Commissioning tools and guidelines

ASHRAE UFAD Guide (2013)


Transition to research on other advanced technologies

By 2012, UFAD was routinely considered as a design option with nearly 10% of all new U.S. office buildings using UFAD.

• Energy savings compared to conventional VAV overhead systems was good (10-15%), but less than hoped for.

• Comfort with adjustable floor diffusers was also better, but there was still room for further improvement.

A review of existing buildings revealed that significant comfort and energy performance enhancements were still needed and possible.

Climate change and state/federal legislation was focusing increased attention on the need for dramatic reductions in building energy use (all new commercial buildings in California must be zero-net-energy (ZNE) by 2030).


We are overcooling buildings in summer, wasting energy and making people uncomfortable.

Energy vs. comfort in buildings

Mean

SBS


7-point Thermal Sensation (TS) scale:

Cool (-3 < TS <-0.5) Neutral (0.5 < TS < 0.5) Warm (0.5 > TS > 3)

Thermal sensations in air-conditioned buildings (Summer, indoor temperatures 70-75ºF, 21 24ºC)

21ºC (70ºF) 23ºC

71ºF 75ºF

22ºC (71.6ºF) 23ºC (73.4ºF) 24ºC (75ºF)

Relatively fewer people are “too warm” in summer we are over-cooling buildings

Data from 160 buildings worldwide, ASHRAE 884-RP database

CENTER FOR THE BUILT ENVIRONMENT JULY 2014 /F

above 85%

Acceptability

80 - 85% 70 - 80%

below 70%

n=26,000

50 60 70 80 90 100

Naturally ventilated buildings (summer)

People are comfortable over a wide range of conditions


Personal comfort systems (PCS) Person-based instead of space-based conditioning

Objective

Explore the ability of PCS to:

Save energy and keep people comfortable over a wider range of room temperatures

Enhance comfort and productivity

Key findings

PCS provide acceptable comfort under temperatures from 64°F to 84°F

Traditional mixing overhead system

Desktop fan Foot warmer Heated and cooled chair


1st generation PCS units

air temperature and occupancy sensors

USB to workstation computer

occupancy sensing pressure plate

Fan unit

Footwarmer unit

Field studies Control and monitoring of:

air temperature

speed and warmth choices

occupancy User controls

4W

average 30W

4W

average 30W


Objective

Demonstrate that using a PCS can reduce HVAC energy consumption while providing individual occupant thermal comfort

Method

Installed 17 PCS units in an office building at UC Berkeley

Monitored plug loads at each workstation

Monitored HVAC energy use using sMAP software

Gradually changed the heating set point from 70 to 66°F (21 to 19°C)

Collect data from September 2012 through April 2013

Project overview


Workstations tested in the office

Office building, UC Berkeley


Interior views of the field demonstration office

Office building, UC Berkeley


Project timeline and set point adjustment

21°C

19°C


Right now, how acceptable is the thermal environment at your workspace?

(Thermal Acceptability)

Right now, you feel:

(Thermal Sensation)

Right now, your feet feel:

(Thermal Sensation)


Preliminary results (footwarmer): Thermal acceptability

Acceptability remained high as indoor heating setpoint in offices dropped from 70 to 66 °F (21 to 19 °C)

Right now, how acceptable is the thermal environment at your workspace?


Preliminary results (footwarmer): energy savings

0

10

02

00

30

04

00

50

06

00

Pow

er

[w]

66 67 68 69 70 70 No PCSSetpoint Temperature

oF

Outside Temperature 52-57 Footwarmer HVAC

Outside Temperature 55-60 Footwarmer HVAC

for each setpoint temperature

Average Footwarmer and HVAC Power

Colder outside

Cool outside

Colder outside

Significant energy savings (~50%) as indoor heating setpoints dropped from 70 to 66 °F (21 to 19 °C)

Minimal energy usage from footwarmer

lower heating setpoint


2nd generation: low-energy heated / cooled chair

Patent pending, company selected to manufacture commercially

Lab studies: 90% acceptability (chair + desk fan) over a range of 64-84°F (18-29 °C) ambient temperature

Field studies: 75 chairs constructed and being tested in UC campus buildings


Energy savings from PCS

Hoyt, T., H.L. Kwang, H. Zhang, E. Arens, T. Webster, 2009,

“Energy savings from extended air temperature setpoints and reductions in room air mixing.” International Conference on Environmental Ergonomics 2009.

Energy savings come from expanding the range of ambient air temperature setpoints (7-15% per °C)

Secondary effects of our PCS

• Makes less-controlled or slowly-responding systems more feasible, e.g., naturally ventilated buildings or radiantly cooled buildings

• Provides more & better sensor data for central HVAC control

Expanded comfort with PCS

PCS

61 64 68 72 75 79 82 86 Temperature (°F)


Chair features

• Highly directed heating and cooling of the body • Energy efficient enclosure and power management


Human subject laboratory test

Approach

Subjects: 12 females and 11 males

Subjects free to control their chair

Chair tested with and without cover fabric

Two cool conditions: 61°F (16°C) and 64°F (18°C)

61°F clothing: T-shirt + long-sleeve shirt + long pants

61°F extra clothing session: Same as above + light jacket

64°F clothing: T-shirt + long-sleeve shirt + long pants

Warm conditions: 84°F (29°C)

T-shirt and long-pants

Extra session with 1.2 watt USB fan


Human subject test

Objective

Quantify the comfortable ambient air temperatures with the chairs

Approach

Human subject test

Development of IT components


Results: Comfort at 61°F

Whole body thermal comfort (16°C)

cover no cover extra clo reference

Very Uncomfortable

Uncomfortable

Just UncomfortableJust Comfortable

Comfortable

Very Comfortable

(61°F)

% voting comfortable: 74 74 78 18




cover no cover reference

Very Uncomfortable

Uncomfortable


Comfortable

Very Comfortable

(64°F)

% voting comfortable: 91 91 31



cover no cover chair+fan reference

Very Uncomfortable

Uncomfortable


Comfortable

Very Comfortable


(84°F)

% voting comfortable: 74 70 91 19


Cesar Chavez Student Union (summer and winter)

Objective

Evaluate thermal comfort provided by PCS in a building without mechanical cooling

Approach

Distributed 14 PCS chairs and 4 footwarmers

Installed wireless temperature sensors in each of 18 workstations

Surveyed - survey (Sept. 2013 Feb. 2014),

1300 responses received

Funding

CEC/PIER, by CIEE (SPEED program)


2. Cesar Chavez Student Union : Summer and winter

Building

No mechanical cooling

Objective

Provide occupant thermal comfort

Approach

Installed wireless temperature sensors in each of 18 workstations

Survey finished

• Without PCSs (Sept. 25 2013, base case)

• With PCSs (Oct. 2013 Feb. 2014)

About 1300 survey responses received

Funding

CIEE through SPEED program

CBE chair

PCS chair

USB fan


Acceptability rates with and without PCS (summer)

Without PCS, acceptability rate is about 50 75% With PCS, acceptability rate is about 75 90%

Indoor air temperature (°F)


Comfort ranges with PCS (summer and winter)

Indoor air temperature (ºF)

PCS keeps occupants in or near comfort over ambient air temperature 68 80ºF

Indoor air temperatures (ºF)

Acceptability rate


Near ZNE buildings with radiant systems

Objective

• Provide new and improved information, guidance, and tools for designing and operating near zero-net-energy (ZNE) buildings using radiant cooling and heating systems

Approach

• Two case studies (in progress)

• EnergyPlus simulations (in progress)

• Developed online map of radiant systems as resource (complete)

• Laboratory testing of radiant cooling loads (complete and published)

Funding and schedule

• California Energy Commission Public Interest Energy Research (CEC/PIER)

• October 2012 March 2015


Near ZNE case studies

Sacramento Municipal Utility District (SMUD) East Campus Operations Center, Sacramento, CA

• 200,000 ft2, LEED Platinum

• Radiant slab, ceiling fans

• Chilled beams

• Geothermal exchange, thermal energy storage

• PV panels

• Stantec

• See CBE Centerline, Winter 2014

David Brower Center, Berkeley, CA • 45,000 ft2, LEED Platinum

• Radiant slab ceiling with UFAD

• Advanced shading, operable windows

• PV panels

• Solomon E.T.C. WRT, Integral Group


Field study approach

Occupant satisfaction survey

Energy Star

Site visit to install wireless measurement toolkit to collect more detailed performance data; supplemented with BMS trend data

CBE survey results Energy use data Indoor climate monitor


Progress: SMUD East Campus Operations Center

Installed 50 wireless sensors (CBE toolkit) on 2nd level open plan office area in December 2013

Collecting live data from CBE toolkit and BMS to sMAP (simple measurement and actuation protocol) for analysis

Working with SMUD building operators to review controls of radiant slab zones

Several operational problems have been identified and corrective adjustments have been made


SMUD office building

Ceiling fans for warm temperature conditions

No compressor cooling from 2-8 pm

Suspended sound-absorbing acoustical panels

Advanced window blinds redirect solar radiation onto ceiling


Installation of wireless sensors

Stratification pole

Radiant ceiling slab surface temperature

Indoor Climate Monitor: air & globe temperature, air velocity, humidity, light level, CO2


Sensors and radiant zones on 2nd level, SMUD


Radiant slab system control in early December Te

mp

erat

ure

(°F

)

Wat

er v

alve

po

siti

on

(%

)

Radiant cooling valve turning on at 10 am – 12 pm each day

Zone air temp.

Slab surface temp.


Heating performance in southeast zone

Radiant heating valve turned on for most of weekend

Tem

pe

ratu

re (

°F)

Slab surface temp.

Zone air temp.

Wat

er v

alve

po

siti

on

(%

)


New setpoint control schedule, SMUD, 2nd level

New Original


Water control valves on 2nd level, SMUD W

ater

val

ve p

osi

tio

n (

%)

• New setpoint schedule implemented on March 13 • Valve operation stops on weekends • Frequency and magnitude of valve operation reduces on weekdays

wknd wknd wknd wknd wknd

March 13


Next steps, SMUD field study

Continue to monitor radiant slab control as warm weather arrives

• Investigate slab pre-cooling strategies based on next day temperature forecast

• Study impact of ceiling fan operation during warm afternoons

Monitor building energy use and compute Energy Star rating

Conduct CBE occupant satisfaction survey

Future field studies planned to investigate impact of installing PCS chairs in SMUD building

• Provide heating during cool mornings

• Provide cooling during warm afternoons


Update of radiant webpages and technology transfer

CBE website has been updated Research on radiant systems: http://www.cbe.berkeley.edu/research/radiant-systems.htm Research on near ZNE buildings with radiant systems: http://www.cbe.berkeley.edu/research/radiant-near-zne-buildings.htm

Review of radiant cooling design methods Critical review of water based radiant cooling system design methods. Feng, J., F. Bauman, and S. Schiavon. Proceedings of Indoor Air 2014, Hong Kong, July 7-12. http://escholarship.org/uc/item/2s00x6ns

Online map of radiant system buildings Online map of buildings using radiant technologies. Karmann C, Schiavon S, Bauman F. Proceedings of Indoor Air 2014, Hong Kong, July 7-12. https://escholarship.org/uc/item/9rs8t4wb

Radiant cooling loads Cooling load calculations for radiant systems: Are they the same as traditional methods? Bauman, F., J. Feng, and S. Schiavon. 2013. ASHRAE Journal 55(12). http://escholarship.org/uc/item/6px642bj Experimental comparison of zone cooling load between radiant and air systems. Feng, J., F Bauman and S. Schiavon. 2014. Accepted in Energy and Buildings. https://escholarship.org/uc/item/9dq6p2j7

http://www.cbe.berkeley.edu/research/radiant-systems.htm





http://www.cbe.berkeley.edu/research/radiant-near-zne-buildings.htm








http://escholarship.org/uc/item/2s00x6ns



https://escholarship.org/uc/item/9rs8t4wb

https://escholarship.org/uc/item/9rs8t4wb

http://escholarship.org/uc/item/6px642bj



https://escholarship.org/uc/item/9dq6p2j7

https://escholarship.org/uc/item/9dq6p2j7


Questions?

Fred Bauman [email protected]

CBE website www.cbe.berkeley.edu

Centerline Newsletter www.cbe.berkeley.edu/centerline

Online map of radiant systems http://bit.ly/RadiantBuildingsCBE

2013 2013

mailto:[email protected]

http://www.cbe.berkeley.edu/

http://www.cbe.berkeley.edu/centerline

http://bit.ly/RadiantBuildingsCBE

http://bit.ly/RadiantBuildingsCBE

Indoor Thermal Environmental Control and Satisfaction...standards (ASHRAE Std. 55, ISO Std. 7730)...

Documents

Transcript of Indoor Thermal Environmental Control and Satisfaction...standards (ASHRAE Std. 55, ISO Std. 7730)...