Heat pump water heater appliance and a method for operating a heat pump water heater appliance

Abstract

A method for operating a water heater appliance includes establishing a standby recovery temperature for the heat pump water heater appliance based at least in part on a set temperature of the heat pump water heater appliance and activating a sealed system of the heat pump water heater appliance if a temperature measurement from a tank temperature sensor is less than the standby recovery temperature. An ambient temperature may also be used to establish the standby recovery temperature for the heat pump water heater appliance. A related water heater appliance is also provided.

What is claimed is: 
     
         1 . A method for operating a heat pump water heater appliance, comprising:
 determining a set temperature of the heat pump water heater appliance;   measuring an ambient temperature about the heat pump water heater appliance with an ambient temperature sensor of the heat pump water heater appliance;   establishing a standby recovery temperature for the heat pump water heater appliance based at least in part on the set temperature of the heat pump water heater appliance and the ambient temperature about the heat pump water heater appliance;   receiving a temperature measurement from a tank temperature sensor of the heat pump water heater appliance during a standby operation of the heat pump water heater appliance; and   activating a sealed system of the heat pump water heater appliance if the temperature measurement from the tank temperature sensor is less than the standby recovery temperature at said step of receiving.   
     
     
         2 . The method of  claim 1 , wherein said step of establishing comprises:
 establishing a first standby recovery temperature for the heat pump water heater appliance if the set temperature of the heat pump water heater appliance is greater than a threshold set temperature; and   establishing a second standby recovery temperature for the heat pump water heater appliance if the set temperature of the heat pump water heater appliance is less than the threshold set temperature, the second standby recovery temperature being greater than the first standby recovery temperature.   
     
     
         3 . The method of  claim 2 , wherein the threshold set temperature is about one hundred and thirty degrees Fahrenheit. 
     
     
         4 . The method of  claim 3 , wherein the first standby recovery temperature is equal to a difference between the set temperature of the heat pump water heater appliance and a first constant temperature, the second standby recovery temperature being equal to a difference between the set temperature of the heat pump water heater appliance and a second constant temperature. 
     
     
         5 . The method of  claim 4 , wherein the first constant temperature is about ten degrees Fahrenheit and the second constant temperature is about five degrees Fahrenheit. 
     
     
         6 . The method of  claim 2 , wherein the second standby recovery temperature is about five degrees Fahrenheit greater than the first standby recovery temperature. 
     
     
         7 . The method of  claim 1 , wherein the standby recovery temperature is less than the set temperature of the heat pump water heater appliance. 
     
     
         8 . The method of  claim 1 , further comprising deactivating the sealed system of the heat pump water heater appliance when the temperature measurement from the tank temperature sensor is the set temperature of the heat pump water heater appliance after said step of activating. 
     
     
         9 . The method of  claim 1 , wherein no water flows out of the heat pump water heater appliance during the standby operation of the heat pump water heater appliance. 
     
     
         10 . The method of  claim 1 , wherein said step of activating comprises activating a compressor of the sealed system. 
     
     
         11 . A heat pump water heater appliance, comprising:
 a tank defining an interior volume;   an ambient temperature sensor;   a tank temperature sensor positioned at the tank and configured for measuring a temperature of water within the interior volume of the tank;   a sealed system operable to heat water within the interior volume of the tank, the sealed system having a compressor; and   a controller in operative communication with the ambient temperature sensor, the tank temperature sensor and the compressor of the sealed system, the controller configured for
 measuring an ambient temperature with the ambient temperature sensor; 
 establishing a standby recovery temperature based at least in part on a set temperature and the ambient temperature; 
 receiving a temperature measurement from the tank temperature sensor during a standby operation; and 
 activating the compressor of the sealed system if the temperature measurement from the tank temperature sensor is less than the standby recovery temperature at said step of receiving. 
   
     
     
         12 . The heat pump water heater appliance of  claim 11 , wherein said step of establishing comprises:
 establishing a first standby recovery temperature if the set temperature is greater than a threshold set temperature; and   establishing a second standby recovery temperature if the set temperature is less than the threshold set temperature, the second standby recovery temperature being greater than the first standby recovery temperature.   
     
     
         13 . The heat pump water heater appliance of  claim 12 , wherein the threshold set temperature is about one hundred and thirty degrees Fahrenheit. 
     
     
         14 . The heat pump water heater appliance of  claim 13 , wherein the first standby recovery temperature is equal to a difference between the set temperature and a first constant temperature, the second standby recovery temperature being equal to a difference between the set temperature and a second constant temperature. 
     
     
         15 . The heat pump water heater appliance of  claim 14 , wherein the first constant temperature is about ten degrees Fahrenheit and the second constant temperature is about five degrees Fahrenheit. 
     
     
         16 . The heat pump water heater appliance of  claim 11 , wherein the controller is further configured for deactivating the compressor of the sealed system when the temperature measurement from the tank temperature sensor is the set temperature of the heat pump water heater appliance after said step of activating. 
     
     
         17 . The heat pump water heater appliance of  claim 11 , wherein the standby recovery temperature is less than the set temperature. 
     
     
         18 . The heat pump water heater appliance of  claim 11 , wherein no water flows out of the tank during the standby operation. 
     
     
         19 . The heat pump water heater appliance of  claim 11 , wherein the tank temperature sensor is the only temperature sensor positioned at the tank and configured for measuring the temperature of water within the interior volume of the tank.