Going for the Max with DELTA UC Berkeley: Center for the Built - - PowerPoint PPT Presentation

Going for the Max with DELTA

UC Berkeley: Center for the Built Environment (CBE: EdwardArens, Hui Zhang) Electrical Engineering and Computer Science (EECS) W asatch Collaboratory (Jeff Muhs) WiTricity Corporation

Problems, opportunities, solutions

Thermal comfort in office buildings: BAD Energy cost of narrow thermostat setpoints

Baltimore example 68 to 78 F 30% savings in summer + 10% savings in winter 40% savings total 68 78

Hoyt, T., E. Arens, and H. Zhang. 2015. Extendingair temperature setpoints: Simulated energy savings and design considerationsfor new and retrofit

• buildings. Building and Environment88, 89-96.

Our solution is to increase the HVAC dead-band to reduce HVAC loads and increase the thermal comfort and productivity of workers.

Huizenga,C; Abbaszadeh,S.; Zagreus, L. and E. Arens (2006). Air quality and thermal comfort in office buildings: Results of a large indoor environmental quality survey. Proceedingof Healthy Buildings 2006, 3, 393 - 397. satisfied with thermal environment

Work performance vs. temperature changes

+6 +3

• 3
• 6

Personal Neutral Temperature Correction (deg. C)

(Productivity curve adapted from Wargocki and Seppanen et al. 2006, “Indoor climate and productivity in offices”,REHVA Guidebook Corrective arrows based on: Zhang, H., E. Arens, Y. Zhai 2015, A review of the corrective power of personal comfort systems in non-neutral ambient environments, Building and Environment Vol. 91, 15 - 41 http://www.sciencedirect.com/science/article/pii/S0360132315001225

Heating DEL TA Cooling DEL TA

3-8 % productivity increase from DELTA temperature corrections

Our suite of DELTA devices for offices

Designed to be both efficient and effective:

• desk fan
• heated/cooled wrist pad
• heated/cooled chair
• heated insole

Wirelessly powered for convenience IOT-connected, to individualize HVAC control

Prototypes

• Very low power use
• User controls for cooling and

heating IOT- data connected:

• occupancy

, control settings, temperature, RH

• Rechargeable battery
• Wirelessly powered

Heated insole Desktop fan H/C wristpad Heated/cooled chair

Warm/cool sensitivity maps of hands and feet

FEMALE Warm sensation Cold sensation FEMALE

Thermal sensation

FEMALE

Thermal sensation

FEMALE

Mapping sensitivity to warmth and coolth

Warm sensation FEMALE Cool sensation FEMALE

) . .u a ( S T ) . u . a ( S T

inner

• uter

inner

• uter

Thermal sensation Thermal sensation

Tests of spot-heated insoles on foot sensation

very hot hot warm

• sl. warm

neutral

• sl. cool

cool cold very cold

Acceptability of DELTA combinations when heating (at 64 F)

thank you for allowing me to use the chair I love it!

• 40 government office workers

(21 females, 19 males)

• Measurements
• Chair occupancy
• Chosen heating/cooling settings
• Occupant surveys
• Indoor environmental conditions
• Chairs improves comfort satisfaction
• 96% thermal acceptability
• People use chairs frequently
• on average 77% of the time used

when seated

• People really like the chairs
• 99% satisfaction

Field study, heated/cooled chair, Apr-Oct 2016

San Mateo County office building, CA

chair

Value to the U.S. of increased productivity

• Approximate annual cost of employment for U.S. office employee:

$83,761 (Bureau of Labor Statistics)

• Number of office employees in U.S: 41.3 million (Bureau of Labor

Statistics)

• Productivity increase from thermal comfort provided by DELTA: 3-8%

(Seppanen 2006); we will assume 3%. However, 100% productivity in the Seppanen curve is for the group neutral temperature, at which at least 20% of the population will be feeling too warm or too cold. Since DELTA corrects all occupants to their individual neutral temperatures, the total of individual productivity increases will be greater than the group increase, say 5% more. (5% + 3% = 8%)

• Conservatively assuming DELTA only improves productivity 20% of

the time for employees in a typical building, the annual productivity increase is $55.4B [($83,761 x 41.3 million x 8%) x 20%]

• Assuming 25% market penetration for DELTA, the total value of

increased productivity in the U.S. is $13.8B ($55.4B x 25%)

Simple payback at the occupant level

• T
• tal system additional price: -$400
• Annual energy costs: -$4
• Annual maintenance costs: -$25
• Annual energy savings from deadband increase: +$75
• Annual increase in productivity: +$1341 ($55.4B/41.3M)
• Simple payback = initial cost / annualized return
• Simple payback: = $400/($1341 + $75 - $4 - $25) = 3.5 months

Summary

Efficient devices have been developed and tested in lab and in field

• Energy efficient
• Effective at providing comfort
• Increases productivity
• Uses IOT to connect to HVAC control
• Cost effective
• Ready for commercialization

13

Next steps?

14

Collaborate with companies interested in developing efficient DELTA

• Efficient heat transfer surfaces---licensees for our IP
• Chair and furniture manufacturers, desktop devices,

shoe insoles

• HVAC control sequences for DELTA-equipped buildings
• Wireless power transfer; untethered devices

Note: The project team is open to both licensing and start-up pathways to market.

earens@berkeley .edu zhanghui@berkeley .edu jeff .muhs@wasatchcollaboratory .com