Research and development of an air-cycle heat-pump water heater. Final report

摘要: A prototype reverse Brayton air cycle heat pump water heater has been designed and built for residential applications. The system consists of a compressor/expander, an air-water exchanger, electric motor, circulation pump, thermostat, fluid management controls. development program consisted market analysis, design study, testing. potential the new high-efficiency approximately 480,000 units/y was identified. retail installation cost this is estimated to be between $500 $600 which $300 more than conventional heater. average payback per unit less 3-1/2 y recurring energy savings after period $105/y at seasonal coefficient performance (COP) 1.7. As part effort, thermodynamic parametric analysis performed on system. It determined that obtain 1.7, isentropic efficiency both compressor expander must least 85%. selected mechanical configuration described. diameter 25 in. height 73 resultsmore » testing showed: electrical motor maximum 78%; 95 119% volumetric 85%; 58% 92%; significant transfer loss 16% occurred in expander; COP 1.26 goal Future work recommended.« less