Heat pump

Abstract

The present invention provides a heat pump that includes: a compressor, a switching valve, an indoor heat exchanger, a first expansion valve, and an outdoor heat exchanger, wherein the outdoor heat exchanger includes: a primary heat exchanging unit connected with the first expansion valve through a refrigerant pipe and through which outdoor air exchanges heat; a secondary heat exchanging unit connected with the switching valve through a refrigerant pipe, disposed behind the primary heat exchanging unit in the flow direction of outdoor air, and through which the outdoor air, which has exchanged heat through the primary heat exchanging unit, exchanges heat; a connection pipe that connects the primary heat exchanging unit and the secondary heat exchanging unit with each other; and a second expansion valve that is disposed in the connection pipe. Therefore, it is possible to improve both cooling performance and heating performance with minimum parts and a simple structure.

What is claimed is: 
     
         1 . A heat pump comprising a compressor, a switching valve, an indoor heat exchanger, a first expansion valve, and an outdoor heat exchanger, wherein a refrigerant flows sequentially through the compressor, the switching valve, the outdoor heat exchanger, the first expansion valve, the indoor heat exchanger, the switching valve, and the compressor in a cooling mode, and the refrigerant flows sequentially through the compressor, the switching valve, the indoor heat exchanger, the first expansion valve, the outdoor heat exchanger, the switching valve, and the compressor in a heating mode,
 wherein the outdoor heat exchanger includes:   a primary heat exchanging unit that is connected with the first expansion valve through a first refrigerant pipe and through which outdoor air exchanges heat;   a secondary heat exchanging unit that is connected with the switching valve through a second refrigerant pipe and disposed behind the primary heat exchanging unit in the flow direction of outdoor air, and through which the outdoor air, which has exchanged heat through the primary heat exchanging unit, exchanges heat;   wherein the primary heat exchanging unit connects with the secondary heat exchanging unit.   
     
     
         2 . The heat pump of  claim 1 , wherein the primary heat exchanging unit and the secondary heat exchanging unit are integrally combined. 
     
     
         3 . The heat pump of  claim 1 , further comprising a heat exchanging unit connection pipe that connects the primary heat exchanging unit with the secondary heat exchanging unit; and
 a second expansion valve that is disposed in the heat exchanging unit connection pipe.   
     
     
         4 . The heat pump of  claim 3 , wherein the primary heat exchanging unit includes a primary microchannel heat exchanger having a first pair of headers connected by a first microchannel, and
 the secondary heat exchanging unit includes at least one secondary microchannel heat exchanger having a second pair of headers connected by a second microchannel and disposed behind the primary microchannel heat exchanger in the flow direction of outdoor air.   
     
     
         5 . The heat pump of  claim 4 , wherein the secondary microchannel heat exchanger includes:
 a first secondary microchannel heat exchanger comprising a first pair of secondary headers and disposed behind the primary microchannel heat exchanger in the flow direction of outdoor air; and   a second secondary microchannel heat exchanger comprising a second pair of secondary headers disposed behind the first secondary microchannel heat exchanger in the flow direction of outdoor air.   
     
     
         6 . The heat pump of  claim 5 , wherein the first pair of headers of the primary microchannel heat exchanger are coupled to the first pair of secondary headers of the first secondary microchannel heat exchanger, and
 the first pair of secondary headers of the first secondary microchannel heat exchanger are coupled to the second pair of secondary headers of the second secondary microchannel heat exchanger.   
     
     
         7 . The heat pump of  claim 5 , wherein the first secondary microchannel heat exchanger is connected with the primary microchannel heat exchanger through the heat exchanging unit connection pipe. 
     
     
         8 . The heat pump of  claim 5 , wherein the second secondary microchannel heat exchanger is connected with the first secondary microchannel heat exchanger through a microchannel heat exchanger connection pipe. 
     
     
         9 . The heat pump of  claim 5 , wherein the second secondary microchannel heat exchanger is connected with the switching valve through the second refrigerant pipe. 
     
     
         10 . The heat pump of  claim 3 , wherein the primary heat exchanging unit includes a primary tube, and
 the secondary heat exchanging unit includes at least one secondary tube disposed behind the primary tube in the flow direction of outdoor air.   
     
     
         11 . The heat pump of  claim 10 , wherein the outdoor heat exchanger further includes common fins in contact with the primary tube and the secondary tube. 
     
     
         12 . The heat pump of  claim 10 , wherein the secondary tube includes:
 a first secondary tube disposed behind the primary tube in the flow direction of outdoor air; and   a second secondary tube disposed behind the first secondary tube in the flow direction of outdoor air.   
     
     
         13 . The heat pump of  claim 12 , wherein the first secondary tube is connected with the primary tube through the heat exchanging unit connection pipe. 
     
     
         14 . The heat pump of  claim 12 , wherein the second secondary tube is connected with the first secondary tube through a tube connection pipe. 
     
     
         15 . The heat pump of  claim 12 , wherein the second secondary tube is connected with the switching valve through the second refrigerant pipe. 
     
     
         16 . The heat pump of  claim 3 , wherein in a heating operation at an outdoor temperature over a predetermined temperature, the first expansion valve is controlled to open at a degree for expanding a refrigerant and the second expansion valve fully opens. 
     
     
         17 . The heat pump of  claim 3 , wherein in a heating operation at an outdoor temperature less than a predetermined temperature, the first expansion valve fully opens and the second expansion valve is controlled to open at a degree for expanding a refrigerant. 
     
     
         18 . The heat pump of  claim 3 , wherein the heat exchanging unit connection pipe includes:
 a primary heat exchanging unit connection pipe that connects the primary heat exchanging unit with the second expansion valve; and   a secondary heat exchanging unit connection pipe that connects the secondary heat exchanging unit with the second expansion valve.   
     
     
         19 . The heat pump of  claim 3 , wherein the secondary heat exchanging unit has a larger heat exchange area for heat exchange with outdoor air than the primary heat exchanging unit. 
     
     
         20 . The heat pump of  claim 3 , wherein the secondary heat exchanging unit has a longer pipe through which a refrigerant passes than the primary heat exchanging unit. 
     
     
         21 . The heat pump of  claim 3 , wherein the secondary heat exchanging unit is larger in number than the primary heat exchanging unit.