Air-conditioning apparatus

Abstract

Obtained is an air-conditioning apparatus capable of having a thin low-pressure gas pipe even when a refrigerant with a low refrigerant density at low pressure is used. An air-conditioning apparatus includes a refrigerant circuit connecting a compressor, a heat source side heat exchanger, expansion devices, and use side heat exchangers with pipes and circulating a refrigerant whose density in a saturated refrigerant gas at 0 degrees C. is 35 to 65% of the density of an R410A refrigerant, and supercooling means (supercooling heat exchanger, expansion device, and bypass) making a liquid temperature sent from the heat source side heat exchanger to the expansion devices be 5 degrees C. or less in a cooling operation.

1 . An air-conditioning apparatus comprising:
 a refrigerant circuit connecting a compressor, a heat source side heat exchanger, an expansion device, and a use side heat exchanger with pipes and circulating a refrigerant whose density in a saturated refrigerant gas at 0 degrees C. is 35 to 65% of a density of an R410A refrigerant; and   supercooling means making a liquid temperature of a high-pressure liquid refrigerant sent from the heat source side heat exchanger to the expansion device be 5 degrees C. or less in a cooling operation.   
     
     
         2 . The air-conditioning apparatus of  claim 1 , wherein the supercooling means makes a degree of supercooling of the high-pressure liquid refrigerant be 44 degrees C. or more. 
     
     
         3 . The air-conditioning apparatus of  claim 1 , wherein, in a heating operation, a liquid temperature of a high-pressure liquid refrigerant sent from the use side heat exchanger to the expansion device is 5 degrees C. or less or a degree of supercooling thereof is 44 degrees C. or more. 
     
     
         4 . The air-conditioning apparatus of  claim 1 , wherein the supercooling means includes a supercooling heat exchanger that exchanges heat between a high-pressure side refrigerant between the heat source side heat exchanger and the expansion device and a low-pressure side refrigerant that is a part of the high-pressure side refrigerant whose pressure has been reduced, so as to cool the high-pressure side refrigerant. 
     
     
         5 . The air-conditioning apparatus of  claim 1 , wherein the supercooling means includes a supercooling circuit connecting a compressor, a condenser, an expansion device, and a supercooling heat exchanger with pipes and circulating the refrigerant, and the supercooling heat exchanger exchanges heat between a low-pressure side refrigerant circulating in the supercooling circuit and the high-pressure side refrigerant between the heat source side heat exchanger and the expansion device in the refrigerant circuit. 
     
     
         6 . The air-conditioning apparatus of  claim 4 , wherein the supercooling heat exchanger is a double-pipe heat exchanger including an annular space and an inner pipe, passing the high-pressure side refrigerant through the annular space, and passing the low-pressure side refrigerant through the inner pipe. 
     
     
         7 . The air-conditioning apparatus of  claim 4 , wherein the supercooling heat exchanger is a plate heat exchanger in which the high-pressure side refrigerant flows from top to bottom and the low-pressure side refrigerant flows from bottom to top. 
     
     
         8 . The air-conditioning apparatus of  claim 1 , wherein HFO1234yf or HFO1234ze is used as the refrigerant. 
     
     
         9 . The air-conditioning apparatus of  claim 1 , wherein the refrigerant circuit includes a plurality of heat exchangers related to heat medium as the use side heat exchanger, the plurality of heat exchangers related to heat medium exchanging heat between the refrigerant and a heat medium different from the refrigerant so as to get the heat media with respective different temperatures by the heat exchanges, and
 the air-conditioning apparatus further comprises a heat medium circuit configured to connect:   a plurality of pumps circulating the heat media related to the heat exchanges in the plurality of heat exchangers related to heat medium;   a load-side heat exchanger exchanging heat between the heat medium and air related to an air-conditioned space; and   a heat medium channel switching device switching passage of the heat medium related to passing through each of the plurality of heat exchangers related to heat medium to the load-side heat exchanger, with pipes.