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Roy Lindsey
6 years ago
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1 This presentation is posted for public use. ACEEE does not endorse any product or service. ACEEE accepts no responsibility for any facts or claims this presentation may contain.

Laboratory Performance Testing & Evaluation of Heat Pump Water Heaters 2011 ACEEE Hot Water Forum Dane Christensen Bethany Sparn Kate Hudon Jeff Maguire May 10, 2011 Photo Credit: Kate Hudon, NREL

2 Laboratory Performance Testing & Evaluation of Heat Pump Water Heaters 2011 ACEEE Hot Water Forum Dane Christensen Bethany Sparn Kate Hudon Jeff Maguire May 10, 2011 Photo Credit: Kate Hudon, NREL PIX # Jeff Maguire is a graduate student at Colorado School of Mines NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

3 HPWH Laboratory Performance Evaluation HPWHs during testing. From left to right: Mfr. A, Mfr. B, Mfr. C, Mfr. D. and Mfr. E. Photo Credits: Kate Hudon, NREL PIX # 18675, 18671, 18667, 18676,

NREL Experimental Capabilities Established HVAC Laboratory (accurate, wide range, best-in-class speed of testing) Experienced with hot water & fluids (Solar, combi, tankless,

Performance Maps to inform component/system models Data to validate or improve models Controls & Operational Modes Data Use: simulation of overall annual impact on whole

4 NREL Experimental Capabilities Established HVAC Laboratory (accurate, wide range, best-in-class speed of testing) Experienced with hot water & fluids (Solar, combi, tankless, gas condensing, electric, desiccants) Statistical characterization of HW event schedules/draw profiles* Within ±5% Energy, ±3% Mass Balances Broad, dense performance datasets Performance Maps to inform component/system models Data to validate or improve models Controls & Operational Modes Data Use: simulation of overall annual impact on whole buildings * See: Photo Credits: Patrick Corkery, NREL PIX # 15013, and Warren Gretz, NREL PIX #

HPWH Experiment Design HPWHs in insulated plenum Well-controlled

flow) & measured Inlet water accurately tempered Inlet pipes

measured Explored: Temperature droop during high draw situations

modes Performance impact of tank, air temp & humidity, various

5 HPWH Experiment Design HPWHs in insulated plenum Well-controlled inlet air conditions Outlets ducted (controlling for pressure & flow) & measured Inlet water accurately tempered Inlet pipes purged before draws Outlet flow & draw profiles controlled & measured Explored: Temperature droop during high draw situations Efficiency & functional characteristics of product operating modes Performance impact of tank, air temp & humidity, various water draw patterns Photo Credits: Kate Hudon, NREL PIX # 18669, and

6 HPWH Draw Profile 1 Recovery Evening Draws Food Prep Hand Washing Dishes Bath Face Wash Morning Draws Showers 5

7 HPWH Draw Profile 2 6

8 Draw Profile Results Unit Tank Size (Gal) First Hour Rating (Gal) Tank Setpoin t Temp ( F) DP1 Shower #2 DP 1 Shower # 3 DP1 Shower #4 DP 1 Evening Draws DP2 Comments A Yes Yes Yes Yes Yes Large tank B Yes No No Yes Yes Lowest heating rate of all units C No No No Yes Yes Pump mixes tank; removing beneficial stratification D Yes Yes Yes Yes Yes Large tank E 66 75* 120 Yes Yes No Yes Yes 4 th shower, outlet dropped to ~103 F Manufacturer Published Values * Unofficial rating + Default setpoint. Minimum set point temperature is 130 F. Unit Maintained outlet water temp > 105 F? 7

9 HPWH Performance Mfr. A 8

10 HPWH Performance Mfr. C 9

11 HPWH Data Application to Simulations Note: Significant fatal errors occur regularly with current model 10

12 HPWH Data Application to Simulations 11

13 Results & Conclusions Products largely deliver as advertised Room for design & control improvements to maximize HW delivery and efficiency during variable demand Preliminary simulations demonstrate potential for significant energy savings, across many regions of USA Early source energy savings estimates: 35 to 60% vs. Electric, in conditioned space -20 to 35% vs. Gas, in conditioned space 25 to 45% vs. Electric, in unconditioned space -40 to 20% vs. Gas, in unconditioned space Best opportunity in Hot, Humid regions Electric: EF = 0.91 Gas: EF = 0.59 All homes: ASHP w/ furnace backup (includes impact on HVAC, across 6 climates/cities) Simulation models need improvement to ensure multisystem interactions are simulated accurately 12

14 Questions? Dane Christensen, PhD Electricity, Resources, and Building Systems Integration National Renewable Energy Laboratory 13

This presentation is posted for public use. ACEEE does not endorse any product or service.

This presentation is posted for public use. ACEEE does not endorse any product or service. ACEEE accepts no responsibility for any facts or claims this presentation may contain. New Methods for Modeling