Refrigeration cycle apparatus

Abstract

An outdoor heat exchanger of an air conditioning apparatus includes a main heat exchange unit and an auxiliary heat exchange unit. When the outdoor heat exchanger is operated to function as an evaporator, in the outdoor heat exchanger, refrigerant flows from the auxiliary heat exchange unit into the main heat exchange unit, and in the auxiliary heat exchange unit, refrigerant flows from a first heat transfer tube of an auxiliary heat exchange unit into a second heat transfer tube of an auxiliary heat exchange unit. When a refrigerant outlet temperature is lower than a freezing point of water, the operation is performed such that a refrigerant inlet temperature of the refrigerant flowing into the auxiliary heat exchange unit is higher than an outdoor air temperature and that a refrigerant outlet temperature of the refrigerant delivered out of the auxiliary heat exchange unit is lower than the outdoor air temperature.

1 . A refrigeration cycle apparatus comprising an outdoor heat exchanger,
 the outdoor heat exchanger including
 a first heat exchange unit, and 
 a second heat exchange unit that is disposed adjacent to the first heat exchange unit, 
   the first heat exchange unit including
 a plurality of fins each formed in a plate shape, 
 a first heat transfer tube disposed to penetrate the plurality of fins, 
 a second heat transfer tube disposed to penetrate the plurality of fins and located at a distance from the first heat transfer tube in a direction crossing a direction in which the first heat transfer tube extends, and 
 a pressure loss mechanism configured to lower pressure of refrigerant flowing through the first heat exchange unit, 
   during an operation of the outdoor heat exchanger functioning as an evaporator, when a temperature of refrigerant flowing out of the first heat exchange unit is lower than a freezing point of water, the refrigeration cycle apparatus operating such that a temperature of refrigerant flowing into the first heat exchange unit is higher than an outdoor air temperature and that the temperature of the refrigerant flowing out of the first heat exchange unit is lower than the outdoor air temperature.   
     
     
         2 . The refrigeration cycle apparatus according to  claim 1 , wherein the operation is performed such that the temperature of the refrigerant flowing out of the first heat exchange unit is higher than a dew point temperature. 
     
     
         3 . The refrigeration cycle apparatus according to  claim 1 , wherein
 the first heat transfer tube has a first end and a second end,   the second heat transfer tube has a third end and a fourth end,   the third end of the second heat transfer tube is connected to the second end of the first heat transfer tube, and   the fourth end of the second heat transfer tube is connected to the second heat exchange unit.   
     
     
         4 . The refrigeration cycle apparatus according to  claim 3 , wherein
 the pressure loss mechanism includes a throttle portion disposed between the second end of the first heat transfer tube and the third end of the second heat transfer tube, and   the throttle portion includes
 a first flow path having a first cross-sectional area, and 
 a second flow path having a second cross-sectional area that is smaller than the first cross-sectional area. 
   
     
     
         5 . The refrigeration cycle apparatus according to  claim 4 , wherein the throttle portion includes a throttle adjustment unit configured to adjust the second cross-sectional area of the second flow path. 
     
     
         6 . The refrigeration cycle apparatus according to  claim 1 , wherein the pressure loss mechanism includes the first heat transfer tube and the second heat transfer tube. 
     
     
         7 . The refrigeration cycle apparatus according to  claim 1 , wherein
 the first heat transfer tube is formed as a first flat tube having a flat cross-sectional shape that has a major axis and a minor axis, and   the second heat transfer tube is formed as a second flat tube having the flat cross-sectional shape, the second flat tube being located at a distance from the first flat tube in a direction in which the major axis extends.   
     
     
         8 . The refrigeration cycle apparatus according to  claim 1 , further comprising an air blower unit configured to blow air from a side on which the first heat transfer tube is disposed toward a side on which the second heat transfer tube is disposed, wherein
 refrigerant flows from the first heat transfer tube into the second heat transfer tube.   
     
     
         9 - 12 . (canceled)