Development of a Nonazeotropic Heat Pump for Crew Hygiene Water Heating

Foster-Miller, Inc., is currently developing a heat pump system to produce hot water for crew hygiene on future manned space missions. The heat pump utilizes waste heat sources and a nonazeotropic working fluid in a highly efficient cycle. The potential benefits include a reduction in peak power draw from 2 to 5 kW for electric cartridge heaters, to just over 100W for the heat pump. As part of the heat pump development program, a unique high efficiency compressor was developed to maintain lubrication in a zero-gravity environment. Initial testing has resulted in measured COPs of 8.5.