Refrigeration Cycle Apparatus

Abstract

A refrigeration cycle apparatus comprises: a compressor; a first heat exchanger; a second heat exchanger; a first decompressing apparatus; an oil separator; a first circulation pathway in which a refrigerant circulates in an order of the compressor, the first heat exchanger, the oil separator, the first decompressing apparatus, and the second heat exchanger; an oil-returned pathway connecting between the oil separator and a suction side of the compressor; a second decompressing apparatus provided in the oil-returned pathway; and a controller configured to control the first decompressing apparatus and the second decompressing apparatus. The controller is configured to set an operation mode to an oil collection mode by adjusting a degree of decompression of the first decompressing apparatus and a degree of decompression of the second decompressing apparatus when the refrigerant and a refrigerating machine oil flowing in the first circulation pathway are separated in the oil separator.

1 . A refrigeration cycle apparatus comprising:
 a compressor;   a first heat exchanger;   a second heat exchanger;   a first decompressing apparatus;   an oil separator;   a first circulation pathway in which a refrigerant circulates in an order of the compressor, the first heat exchanger, the oil separator, the first decompressing apparatus, and the second heat exchanger;   an oil-returned pathway connecting between the oil separator and a suction side of the compressor;   a second decompressing apparatus provided in the oil-returned pathway; and   a controller configured to control the first decompressing apparatus and the second decompressing apparatus,   the controller being configured to set an operation mode to an oil collection mode in which the oil-returned pathway is opened by adjusting a degree of decompression of the second decompressing apparatus when the refrigerant and a refrigerating machine oil flowing in the first circulation pathway are separated in the oil separator,   the controller being configured to set the operation mode to a normal mode in which the oil-returned pathway is closed by adjusting the degree of decompression of the second decompressing apparatus when the refrigerant and the refrigerating machine oil flowing in the first circulation pathway are not separated in the oil separator.   
     
     
         2 . (canceled) 
     
     
         3 . The refrigeration cycle apparatus according to  claim 1 , wherein in the oil collection mode, the controller is configured to adjust a degree of decompression of the first decompressing apparatus to suppress an amount of the refrigerant flowing from the oil separator into the first decompressing apparatus and decrease a temperature of the refrigerant flowing into the oil separator as compared with the normal mode. 
     
     
         4 . The refrigeration cycle apparatus according to  claim 1 , further comprising a first temperature sensor configured to detect a temperature of the refrigerant flowing on a discharge side of the compressor, wherein
 the controller is configured to determine whether to set the operation mode to the oil collection mode by using the temperature detected by the first temperature sensor when the refrigeration cycle apparatus is started.   
     
     
         5 . The refrigeration cycle apparatus according to  claim 4 , further comprising a second temperature sensor configured to detect a temperature of the refrigerant flowing in the first heat exchanger, wherein
 the controller is configured to determine whether to set the operation mode to the oil collection mode based on a degree of superheat calculated from the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor.   
     
     
         6 . The refrigeration cycle apparatus according to  claim 1 , further comprising a third temperature sensor configured to detect a temperature of the refrigerant flowing in the second heat exchanger or a temperature of outdoor air around the second heat exchanger, wherein
 the controller is configured to determine whether to set the operation mode to the oil collection mode by using the temperature detected by the third temperature sensor during an operation of the refrigeration cycle apparatus.   
     
     
         7 . The refrigeration cycle apparatus according to  claim 1 , further comprising a third heat exchanger configured to exchange heat between the refrigerant flowing between the first heat exchanger and the oil separator and the refrigerant flowing between the second decompressing apparatus and the compressor. 
     
     
         8 . The refrigeration cycle apparatus according to  claim 1 , further comprising a four-way valve, wherein
 the four-way valve is configured to switch a direction of circulation of the refrigerant between the first circulation pathway and a second circulation pathway,   in the second circulation pathway, the refrigerant circulates in an order of the compressor, the second heat exchanger, the first decompressing apparatus, the oil separator, and the first heat exchanger, and   the oil separator is configured to return the refrigerant in a gaseous state to the compressor via the oil-returned pathway when the refrigerant circulates in the second circulation pathway.   
     
     
         9 . The refrigeration cycle apparatus according to  claim 1 , further comprising:
 a four-way valve; and   a third decompressing apparatus provided in a pathway for the refrigerant flowing between the oil separator and the first heat exchanger, wherein   the four-way valve is configured to switch a direction of circulation of the refrigerant between the first circulation pathway and a second circulation pathway,   in the second circulation pathway, the refrigerant circulates in an order of the compressor, the second heat exchanger, the first decompressing apparatus, the oil separator, the third decompressing apparatus, and the first heat exchanger, and   the controller is configured to set the operation mode to the oil collection mode by adjusting a degree of decompression of the first decompressing apparatus and the degree of decompression of the second decompressing apparatus when the refrigerant and the refrigerating machine oil flowing in the second circulation pathway are separated in the oil separator.