Refrigeration device and air conditioner using it

PROBLEM TO BE SOLVED: To prevent liquid injection and a reverse flow by positively carrying out determination of an injection prohibition area in freezing equipment carrying out gas injection to an intermediate pressure of a compressor. SOLUTION: The freezing equipment is provided with a two stage compressor having a high stage compressor part and a low stage compressor part, a high pressure side heat exchanger, a gas-liquid separator, a low pressure side heat exchanger, an upstream side pressure reducing device provided between the high pressure side heat exchanger and the gas-liquid separator, a downstream side pressure reducing device provided between the gas-liquid separator and the low pressure side heat exchanger, an injection piping guiding an intermediate pressure refrigerant from a gas outlet of the gas-liquid separator to a suction side of the high stage compressor part, and an injection control valve provided in a midway part of the injection piping. An opening of the downstream side pressure reducing device is adjusted on the basis of a temperature of the gas-liquid separator, and a compressor side temperature of the injection piping. COPYRIGHT: (C)2006,JPO&NCIPI