HEATING/COOLING SYSTEM BY MULTI STAGE TYPE HEAT PUMP

摘要

The cooling/heating system using a multistage heat pump is capable of preventing heating efficiency from being deteriorated even through an outdoor temperature falls down -15 deg.C during heating in winter and raising coefficient of performance up to over 5 to thereby reduce power cost. In the cooling/heating system, a heat medium preheater(46) is installed on a pipe path between an outdoor heat exchanger(40) and an all direction valve(42), an expansion orifice(50) is installed on a pipe path between the outdoor heat exchanger(40) and an indoor heat exchanger(48), an heat exchanger(58) is installed on a pipe path on which a high temperature and high pressure heat medium gas discharged from a compressor(44) flows, and an accumulator(62) is installed on a pipe path between the compressor(44) and the heat exchanger(58).