Indoor Thermal Environmental Control and Satisfaction...standards (ASHRAE Std. 55, ISO Std. 7730)...
Transcript of 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
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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
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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
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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
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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.
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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
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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
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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
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Comfort: part of Indoor Environmental Quality (IEQ)
Thermal comfort Lighting / visual comfort
Indoor air quality Acoustics
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30-year costs of a commercial building
Personnel 92%
6%
2%
Operations & Maintenance
Capital costs
Why is IEQ important? (Hint: follow the $$)
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Typical office building costs in $/sf per year
Why is IEQ important? (Hint: follow the $$)
Annually, people costs are 2 orders of magnitude more than energy costs
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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
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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.
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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
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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.
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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)
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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.
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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
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Basics: Overhead (OH) vs. UFAD
15-18°C (60-65°F) supply temp.
13-14°C (55-57°F) supply temp.
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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
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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
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Design practice • Lack of familiarity
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•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
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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)
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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).
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We are overcooling buildings in summer, wasting energy and making people uncomfortable.
Energy vs. comfort in buildings
Mean
SBS
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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
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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
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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
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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
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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
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Workstations tested in the office
Office building, UC Berkeley
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Interior views of the field demonstration office
Office building, UC Berkeley
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Project timeline and set point adjustment
21°C
19°C
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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)
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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?
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Preliminary results (footwarmer): energy savings
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Outside Temperature 55-60 Footwarmer HVAC
for each setpoint temperature
Average Footwarmer and HVAC Power
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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
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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
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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)
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Chair features
• Highly directed heating and cooling of the body • Energy efficient enclosure and power management
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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
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Human subject test
Objective
Quantify the comfortable ambient air temperatures with the chairs
Approach
Human subject test
Development of IT components
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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
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Results: Comfort at 64°F
Whole body thermal comfort (18°C)
cover no cover reference
Very Uncomfortable
Uncomfortable
Just UncomfortableJust Comfortable
Comfortable
Very Comfortable
(64°F)
% voting comfortable: 91 91 31
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Whole body thermal comfort (29°C)
cover no cover chair+fan reference
Very Uncomfortable
Uncomfortable
Just UncomfortableJust Comfortable
Comfortable
Very Comfortable
Results: Comfort at 84°F
(84°F)
% voting comfortable: 74 70 91 19
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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)
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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
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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)
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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
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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
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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
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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
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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
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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
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Installation of wireless sensors
Stratification pole
Radiant ceiling slab surface temperature
Indoor Climate Monitor: air & globe temperature, air velocity, humidity, light level, CO2
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Sensors and radiant zones on 2nd level, SMUD
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Radiant slab system control in early December Te
mp
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(°F
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Wat
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alve
po
siti
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(%
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Radiant cooling valve turning on at 10 am – 12 pm each day
Zone air temp.
Slab surface temp.
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Heating performance in southeast zone
Radiant heating valve turned on for most of weekend
Tem
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°F)
Slab surface temp.
Zone air temp.
Wat
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New setpoint control schedule, SMUD, 2nd level
New Original
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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
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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
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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
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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