Heat pump water heater

Abstract

A heat pump water heater in which the number of components is small, a measure against drain pan freezing is realized with a simple structure, and a drain reservoir is difficult to be generated in the drain pan is obtained. This heat pump water heater is provided with a refrigerating cycle in which a compressor 1 , a four-way valve 2 that switches a flow direction of a refrigerant, a water heat exchanger 3 that exchanges heat between the refrigerant and water, an expansion valve 4 that adjusts and decompresses a flow rate of the refrigerant, and an air heat exchanger 5 that exchanges heat between air and the refrigerant are connected sequentially by a refrigerant pipeline, a water circuit in which the water heat exchanger 3 , a hot water tank 7 which reserves water heated by the water heat exchanger 3 , and a pump 11 are connected sequentially, and a three-way valve 12 disposed between the pump 11 and the water heat exchanger 3 so that a water circuit flows to a lower-stage path 5 a of the air heat exchanger and returns to the water heat exchanger 3 , and a control portion that switches the three-way valve 12 of the water circuit so that high-temperature water in the hot water tank flows to the lower-stage path 5 a of the air heat exchanger during defrosting operation is disposed.

1 . A heat pump water heater, comprising:
 a refrigerating cycle in which a compressor, a four-way valve that switches a flow direction of a refrigerant, a water heat exchanger that performs heat exchange between said refrigerant and water, an expansion mechanism that adjusts a flow rate of the refrigerant and decompresses, and an air heat exchanger that performs heat exchange between the air and the refrigerant are sequentially and circularly connected by a pipeline;   a water circuit in which said water heat exchanger, a hot water tank that reserves water heated by said water heat exchanger, and a pump are sequentially and circularly connected by a pipeline;   a water channel pipeline disposed in a lower stage of said air heat exchanger;   a path switching valve disposed in the water circuit between said pump and said water heat exchanger;   a bypass circuit connected between said path switching valve and an inlet of said water channel pipeline and connecting an outlet of said water channel pipeline to the water circuit between said path switching valve and an inlet of said water heat exchanger; and   a control portion that executes switching control of said four-way valve and said path switching valve, wherein   said control portion switches a flow direction of the refrigerant in said refrigerating cycle by switching said four-way valve on the basis of predetermined information during defrosting operation and allows high-temperature water in said hot water tank to flow through the water channel pipeline of said air heat exchanger via said bypass circuit by switching said path switching valve.   
     
     
         2 . The heat pump water heater of  claim 1 , further comprising
 a drain pan that collects drained water heated by the water channel pipeline of said air heat exchanger and dropped from said air heat exchanger, in the lower part of said air heat exchanger.   
     
     
         3 . The heat pump water heater of  claim 1 , wherein
 a cut-and-raised portion is not disposed in the fin of the water channel pipeline portion of said air heat exchanger.   
     
     
         4 . The heat pump water heater of  claim 1 , wherein
 in the vicinity of said channel switching valve, said water heat exchanger, the water channel pipeline of said air heat exchanger, and a circuit connection joint on the water inlet side are disposed.   
     
     
         5 . The heat pump water heater of  claim 1 , wherein
 said path switching valve is disposed on the inlet side of said water heat exchanger.   
     
     
         6 . The heat pump water heater of  claim 1 , wherein
 said path switching valve is a three-way valve.   
     
     
         7 . The heat pump water heater of  claim 1 , wherein
 said control portion executes defrosting operation on the basis of an instruction from a user.   
     
     
         8 . The heat pump water heater of  claim 1 , wherein
 said control portion executes the defrosting operation when efficiency falls below a reference value set in advance.