| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem with a pump-down operation, wherein there is a possibility that hydrofluoroolefin may be decomposed due to a rise of a temperature of a sliding part during the pump-down operation since the hydrofluoroolefin is liable to be decomposed. <P>SOLUTION: An outdoor machine 100 includes: a compressor 1; an outdoor heat exchanger 2; an outdoor blower 3; an expansion valve 4; a two-way valve 5; and a three-way valve 8. An indoor machine 101 includes an indoor heat exchanger 6 and an indoor blower 7. HFO-1234yf is used as an operation coolant. A time of the pump-down operation is shortened by being shifted to pump-down by raising a gas ratio of a coolant which exists in liquid-side connecting piping 21 immediately before the pump-down, the rise of the temperature of the sliding part of the compressor 1 is suppressed, and the decomposition of the coolant is prevented, thus improving reliability. <P>COPYRIGHT: (C)2012,JPO&INPIT |
