Satisfying more while consuming less--

Transcription

1 Satisfying more while consuming less-- the promise of personal comfort systems Edward Arens Center for the Built Environment UC Berkeley

2 Part 1. Center for the Built Environment (CBE) Building science laboratory founded at UC Berkeley in 1980 CBE established in 1997 with support from the National Science Foundation Industry Advisory Board sponsors and guides the research agenda Semi-annual meetings on April and October emphasize collaboration, shared goals, and problem solving

3 CBE Industry Advisory Board Architecture EHDD Architecture Perkins+Will Yost Grube Hall Architecture WRNS Studio ZGF Architects Engineering Affiliated Engineers Inc. Arup Buro Happold Charles M. Salter Assoc. CPP Wind Engineering Guttmann & Blaevoet Integral Group P2S Engineering Syska Hennessy Group Taylor Engineering WSP Architecture+Engineering DIALOG HGA Architects and Engineers HOK LPA Inc. RTKL Associates Stantec SOM Contractors DPR Construction Southland Industries Webcor Builders Government California Energy Commission U.S. Department of Defense U.S. General Services Administration Manufacturing Armstrong BASF Corporation Big Ass Fans Ingersoll Rand Price Industries Viega REHAU Utilities Pacific Gas & Electric San Diego Gas & Electric Southern California Edison Technology & More Aclima (2017) Delos Living LLC Genentech (2017) Google, Inc.

4 CBE research areas 1. HVAC Systems Underfloor air distribution (UFAD) Radiant cooling systems Room air movement Personal comfort systems (PCS) Advanced integrated systems Developing simulation tools 2. Envelope Systems Window shading Window ventilation Mixed-mode buildings

5 CBE research areas, continued 3. Indoor Environmental Quality (IEQ) Occupant IEQ surveys Advanced thermal comfort model Acoustical performance 4. Controls and Information Technology Wireless sensing and controls Demand response technologies 5. Standards (ASHRAE Std 55) Adaptive comfort model Air movement standards Solar impact on comfort Performance Measurement (PMP) Computer tools for design

6 CBE Occupant Satisfaction Survey Standardized method for studying building performance from occupants point of view Web-based since 2000, 1000 buildings, 100,000+responses Used for: diagnosing problems commissioning benchmarking research

7 CBE s publications and links:

8 Buildings and energy use US DOE Quadrennial Technology Review,

9 Building economics occupants rule Terrapin Bright Green 2012

10 What do the occupants think of their buildings? CBE survey of 351 bldgs and 52,980 occupants Frontczak, Schiavon et al Occupant satisfaction and IEQ Indoor Air

11 Further bad news Only 11% of buildings meet ASHRAE Std.55 s 80% acceptability threshold Number of buildings % 10-19% 20-29% 24% 21% 14% 15% 15% 9% 1% 1% 30-39% 40-49% 50-50% 60-69% Percent satisfied 70-79% 80-89% 90-99% 100% Percent satisfied: Top 4 points (>=0) on 7-point satisfaction scale Air quality and thermal comfort in office buildings: Results of a large indoor environmental quality survey

12 HVAC: current state of practice.. Focus is on zones Goal is uniform conditions Over space, time Sparse sensing Sparse occupant feedback Restricted setpoint ranges Temperature Air supply rate Overcooled in summer Overheated in winter Energy intensive! Satisfies <80% of occupants

13 Comfort zones (ASHRAE Standard 55) In practice: 71 75ºF

14 Setpoint range has a large effect on HVAC energy Hoyt, Tyler; Arens, Edward; & Zhang, Hui. (2014). Extending air temperature setpoints: Simulated energy savings and design considerations for new and retrofit buildings. Building and Environment. doi: /j.buildenv

15 Expanding setpoints saves 5-7% HVAC energy, per degree F! Baltimore example 68 to 78 F 30% savings in summer + 10% savings in winter 40% savings total 68 76

16 Loosening the range of temperature setpoints Comfort zones, adaptive and beyond PCS

17 Providing comfort personally Advantages: Conditioning the occupant s body requires 1/100 the energy of conditioning the room, per occupant PCS enables less-controlled or slowly-responding systems by assuring comfort, e.g., naturally ventilated buildings or radiantly cooled buildings IOT PCS can serve as sensors for central HVAC Design considerations: Bodies are somewhat locatable: tend to be near the floor, at workstation, on chair Condition the body parts that have most impact on comfort

18 Personal comfort systems developed at CBE Purdue Purdue Conference, July July 10, , 2018

19 Background on PCS development

20 Human testing of segment sensations

21 Findings for cool environments Overall discomfort dictated by local discomfort Extremities are most important in cool environments: vasoconstriction is uncomfortable

22 Findings for warm environments Overall discomfort dictated by local discomfort The head is most important in warm conditions Both head and hands dilated

23 And in more detail Palm thermal sensitivity test points Warm sensation FEMALE Cold sensation FEMALE TS (a.u.) TS (a.u.)

24 PCS system desktop components Cold conditions Warm conditions Palm warmer Heated keyboard Head cooling device Foot warmer Hand cooling device

25 Fan+footwarmer PCS Fan unit USB to workstation computer 4W air temperature and occupancy sensors Controls Footwarmer unit average 20W occupancy sensing pressure plate

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27 Functional wireless power transfer desk fan! Built on ARCTIC Breeze USB desktop fan 2.8 W max draw 5V)

28 Wirelessly powered insole Wireless shoe insole 3D print Wireless wrist warmer/cooler WiTricity electronics EECS electronics + a battery Receiver coil Based on orthotic insole

29 Wrist warmer and cooler

30 Personal comfort chair prototype User controls for cooling and heating Rechargeable battery Low power use: Max heating power 14 W Max cooling power 3.6 W Senses occupancy, temperature, humidity, user settings , WiFi, and Bluetooth communication with BMS

31 Digital controls communicate with BMS

32 Lab tests of comfortable range 64-84F Very Comfortable Whole body thermal co Comfortable Just Comfortable Just Uncomfortable Uncomfortable Very Uncomfortable cover no cover referen

33 Field study example Doe Library Annex: Winter Objectives Demonstrate the use of fan/footwarmer over a whole winter Provide occupant thermal comfort Reduce HVAC energy consumption Results Equivalent comfort was maintained with heating setpoint lowered from 70 F to 66 F Over 30% savings in heating energy over winter

34 Thermal acceptability unchanged Right now, how acceptable is the thermal environment at your workspace?

35 PCS chair comfort in poor building achieved 80% acceptability

36 Field study, heated/cooled chair, Apr-Oct 2016 San Mateo County office building, CA Chairs improves comfort satisfaction 96% thermal acceptability 40 government office workers (21 females, 19 males) People use chairs frequently on average 77% of the time used when seated Measurements Chair occupancy Chosen heating/cooling settings Occupant surveys Indoor environmental conditions People really like the chairs 99% satisfaction

37 PCS chair control behavior: snapshot of one person Occupants are not always stationary or at sedentary metabolic rates. During transient states, people often use the chair to cool down.

38 Hybrid approach to granting personal control

39 Revisiting room air circulation Purdue Purdue Conference, July July 10, , 2018

40 Air movement a long neglected variable Traditional architecture relied on it until AC swept it away in the 50 s and 60 s Fanger: the preferred environment is cool, dry, and still But circulating air can be efficient! A 5 diameter DC fan now uses 16W at high setting; a breakthrough analogous to LED lighting After years of banishment, will today s occupants accept it? This was a big issue in Std Purdue 55 Conference, deliberations July 10, 2018 prior to 2010

41 Do people like air movement? Preferences surveyed in office studies were pretty clear Air Movement Preference, ASHRAE Sensation -0.7 to 1.5 (n = 3230) Want More: 52% No Change: 45% Want Less: (Data from ASHRAE Database1)

42 This led to elevated air movement ASHRAE standard ASHRAE Std s air movement provisions revised to permit higher levels in neutral to warm conditions (Arens et al. 2010)

43 92% occupant satisfaction where AC cooling setpoint is 82F Zero Net Energy Building. DPR Construction in Phoenix AZ.

44 Thermal comfort with ceiling fan Thermal comfort maintained with vertical air flow very co m forta ble 3 69 F 60% 69 F 80% 82 F 60% 82 F 80% 86 F 60% 86 F 80% no fan Thermal comfort m/s 0.7 m/s 0.85 m/s 1.2 m/s 1.6 m/s 1.8 m/s very uncom fortable Effective temperature ( F)

45 Breathing zone CO2 bubble and fans Simulated scenarios in the office environment; 40 subjects Sitting in the empty desk Desk with the oscillating table fan Desktop monitor Laptop CO 2 level above the background [ppm] empty desk desktop laptop desk with monitor table fan For CO 2 dilution, use of the fans is equivalent to increase of ventilation supply of 12 l/s per person.

46 Recent progress in the ceiling fan industry Appearance big progress in the fan industry Power efficiency greatly improved with DC motors Intelligent controls for comfort and energy effectiveness links with Nest and internet home automation We believe the momentum is underway for cooling with air movement An elevated air speed should be the base condition before compressor cooling is initiated this requires a fundamental change to the practice of the last 50 years, but is not beyond reach

47 Creating architectural acceptance

48 Challenges of PCS and air movement The potential for better comfort and energy savings is enormous. But how to get PCS going? Challenges: Who pays and who benefits from PCS? How to make sure that the PCS is energy efficient? How do designers assure that the PCS will be there? (ceiling fans are a little more permanent than PCS) It seems that LEED and other rating systems might provide a way operational plans to make PCS available might be a prerequisite to high ratings.

49 Recap of the talk Many people are not finding buildings comfortable People s temperatures differ, inter- and intra-, by ~3K (5F) Tight deadbands to provide comfort are energy-intensive Personal comfort systems provide corrective power You don t need a compressor to cool an occupant convection may do! Room fans are now very energy efficient Any time the AC is on, room air should be moving Challenges and promise in achieving distributed personal HVAC

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