Heat pump water heater appliance

Abstract

Water heater appliances and methods for operating water heater appliances are provided. A water heater appliance includes a tank defining an interior volume, and a sealed system for heating water within the interior volume. The sealed system includes a compressor operable to compress refrigerant, a first condenser downstream of and in fluid communication with the compressor, and a second condenser downstream of and in fluid communication with the compressor. The first and second condensers are each operable to heat water within the interior volume using energy from the refrigerant. The sealed system additionally includes a valve in fluid communication with the first and second condensers and configured to vary a ratio of refrigerant flow through the first and second condensers.

What is claimed is: 
     
         1 . A water heater appliance comprising:
 a tank defining an interior volume; and   a sealed system for heating water within the interior volume of the tank, the sealed system comprising
 a compressor operable to compress a refrigerant; 
 a first condenser positioned downstream of and in fluid communication with the compressor; 
 a second condenser positioned downstream of and in fluid communication with the compressor, the first and second condensers each operable to heat water within the interior volume of the tank using energy from the refrigerant; and 
 a valve in fluid communication with the first condenser and the second condenser and configured to vary a ratio of refrigerant flow through the first condenser and through the second condenser. 
   
     
     
         2 . The water heater appliance of  claim 1 , wherein the first condenser is configured in parallel flow with the second condenser. 
     
     
         3 . The water heater appliance of  claim 1 , wherein the water heater appliance defines a vertical direction, and wherein the first condenser is positioned above the second condenser along the vertical direction. 
     
     
         4 . The water heater appliance of  claim 1 , wherein the first condenser and the second condenser each surround the tank. 
     
     
         5 . The water heater appliance of  claim 1 , wherein the water heater appliance defines a vertical direction, wherein the tank comprises an upper portion and a lower portion each positioned along the vertical direction, and wherein the first condenser surrounds the upper portion and the second condenser surrounds the lower portion. 
     
     
         6 . The water heater appliance of  claim 1 , wherein the valve is positioned downstream from the first condenser and downstream from the second condenser. 
     
     
         7 . The water heater appliance of  claim 1 , wherein the valve is positioned upstream from the first condenser and upstream from the second condenser. 
     
     
         8 . The water heater appliance of  claim 1 , wherein the valve is a three-way valve utilizing a stepper motor. 
     
     
         9 . The water heater appliance of  claim 1 , wherein the valve comprises a first port in fluid communication with the first condenser, a second port in fluid communication with the second condenser, and a third port in fluid communication with the compressor or an expansion device. 
     
     
         10 . The water heater appliance of  claim 1 , further comprising
 a casing extending around at least a portion of the tank, wherein the valve is positioned within the casing.   
     
     
         11 . The water heater appliance of  claim 10 , wherein the compressor, the first condenser, and the second condenser are each positioned within the casing. 
     
     
         12 . The water heater appliance of  claim 1 , further comprising a hot water conduit and a cold water conduit each extending into the interior volume of the tank, the cold water conduit having a length within the interior volume greater than a length of the hot water conduit within the interior volume. 
     
     
         13 . A method for operating a water heater appliance, the method comprising:
 flowing a refrigerant through a compressor;   flowing a first portion of the refrigerant from the compressor through a first condenser operable to heat water within an interior volume of a tank of the water heater appliance;   flowing a second portion of the refrigerant from the compressor through a second condenser operable to heat water within the interior volume of the tank of the water heater appliance; and   varying a ratio of refrigerant flow through the first condenser and through the second condenser using a valve in fluid communication with the first condenser and the second condenser.   
     
     
         14 . The method of  claim 13 , further comprising
 flowing the refrigerant from the first condenser and from the second condenser through the valve.   
     
     
         15 . The method of  claim 13 , further comprising
 flowing the refrigerant from the valve through the first condenser and through the second condenser.   
     
     
         16 . The method of  claim 13 , wherein the first condenser is configured in parallel flow with the second condenser. 
     
     
         17 . The method of  claim 13 , further comprising
 flowing the refrigerant from the first condenser and from the second condenser through an expansion device.   
     
     
         18 . The method of  claim 13 , wherein the tank comprises an upper portion and a lower portion each defined along a vertical direction, and wherein the first condenser surrounds the upper portion and the second condenser surrounds the lower portion. 
     
     
         19 . The method of  claim 13 , wherein the water heater appliance further comprises a casing surrounding at least a portion of the tank, and wherein the valve and the condenser are positioned within the casing. 
     
     
         20 . The method of  claim 13 , further comprising
 determining a temperature of the water within the inner volume of the tank of the water heater appliance, and wherein said step of varying the ratio of refrigerant flow through the first condenser and through the second condenser is performed in response to the determined temperature of the water within the inner volume of the tank of the water heater appliance.