Heat pump water heater

Abstract

A heat pump water heater includes a heat pump unit a hot water storage tank including a high temperature part and a low temperature part; a water inlet pipe for supplying water from the low temperature part to the heat pump unit; a heat storage unit that absorbs heat from water flowing through the water inlet pipe and stores the heat; a first branch valve provided between the low temperature part and the heat storage unit to switch a flow path in the water inlet pipe; and a first bypass pipe connecting a part between the heat storage unit and the heat pump unit to the first branch valve.

1 . A heat pump water heater comprising:
 a heat pump unit heating water,   a hot water storage tank including a high temperature part for storing water heated by the heat pump unit and a low temperature part for storing water having a temperature lower than the water stored in the high temperature part,   a water inlet pipe for supplying water from the low temperature part to the heat pump unit,   a heat storage unit absorbing heat from water flowing through the water inlet pipe and storing the heat,   a first branch valve provided between the low temperature part and the heat storage unit to switch a flow path in the water inlet pipe; and   a first bypass pipe connecting a part between the heat storage unit and the heat pump unit to the first branch valve,   a hot water outlet pipe for supplying water from the heat pump unit to the high temperature part,   a second branch valve provided between the heat pump unit and the heat storage unit to switch a flow path in the hot water outlet pipe; and   a second bypass pipe connecting a part between the heat storage unit and the high temperature part to the second branch valve,   the first branch valve can switch between a flow path through which the low temperature part is connected to the heat pump unit via the heat storage unit and a flow path through which the low temperature part is connected to the heat pump unit not via the heat storage unit but via the first bypass pipe, the heat storage unit absorbs heat from water flowing through the hot water outlet pipe and stores the heat, and   the second branch valve can switch between a flow path through which the high temperature part is connected to the heat pump unit via the heat storage unit and a flow path through which the high temperature part is connected to the heat pump unit not via the heat storage unit but via the second bypass pipe.   
     
     
         2 . The heat pump water heater according to  claim 1 , wherein
 when the temperature of water flowing out of the low temperature part is higher than the temperature in the heat storage unit, the first branch valve switches the flow path in the water inlet pipe to the flow path through which the low temperature part is connected to the heat pump unit via the heat storage unit, and   when the temperature of water flowing out of the low temperature part is lower than the temperature in the heat storage unit, the first branch valve switches the flow path in the water inlet pipe to the flow path through which the low temperature part is connected to the heat pump unit not via the heat storage unit but via the first bypass pipe.   
     
     
         3 . (canceled) 
     
     
         4 . The heat pump water heater according to  claim 1 , wherein
 when the temperature of water flowing out of the heat pump unit is lower than the temperature in the heat storage unit, the second branch valve switches the flow path in the hot water outlet pipe to the flow path through which the high temperature part is connected to the heat pump unit via the heat storage unit, and   when the temperature of water flowing out of the heat pump unit is higher than the temperature in the heat storage unit, the second branch valve switches the flow path in the water inlet pipe to the flow path through which the high temperature part is connected to the heat pump unit not via the heat storage unit but via the second bypass pipe.   
     
     
         5 . The heat pump water heater according to  claim 1 , wherein in a case in which hot water output is to be performed, the hot water output being such that water flowing out of the heat pump unit is mixed through a mixed valve and supplied to outside,
 when the temperature of water flowing out of the heat pump unit is lower than the temperature in the heat storage unit, the second branch valve switches the flow path in the hot water outlet pipe to the flow path through which the high temperature part is connected to the heat pump unit via the heat storage unit, and   when the temperature of water flowing out of the heat pump unit is higher than the temperature in the heat storage unit, the second branch valve switches the flow path in the water inlet pipe to the flow path through which the high temperature part is connected to the heat pump unit not via the heat storage unit but via the second bypass pipe.