Systems and Methods for Heating Water Using Heat Pump Water Heaters Having Natural Convection Evaporator Heat Exchangers

Abstract

A heat pump water heater is disclosed herein. The heat pump water heater includes an outer casing and a water tank disposed within the outer casing. The water tank includes a top wall, a bottom wall, and a side wall extending between and connected to the bottom wall and the top wall and has a hot water outlet and a cold water inlet configured to enable water to flow into and out of the water tank. Additionally, the water heater includes a condenser heat exchanger surrounding at least a portion of the side wall, an insulation jacket disposed around at least the side wall and the bottom wall of the water tank and the condenser heat exchanger, a natural convection evaporator disposed about the side wall and employing no fan to direct heating medium to the refrigerant, and a compressor and tubing connected to the condenser heat exchanger and the natural convection evaporator.

That which is claimed is: 
     
         1 . A water heater, comprising:
 a water tank;   a condenser heat exchanger disposed about at least a portion of the water tank; and   a natural convection evaporator heat exchanger disposed about at least a portion of the water tank,   wherein the natural convection evaporator heat exchanger is configured to exchange heat between water in the water tank and ambient air using natural convection.   
     
     
         2 . The water heater of  claim 1 , further comprising a refrigerant configured to pass through a coil of the natural convection evaporator heat exchanger, wherein a temperature difference between the ambient air and the refrigerant is used as a basis for warmer air to heat the refrigerant based on the ambient air surrounding the natural convection evaporator heat exchanger rising along the natural convection evaporator heat exchanger and exchanging heat with the refrigerant therein. 
     
     
         3 . The water heater of  claim 1 , further comprising an insulation jacket disposed about at least the water tank and the condenser heat exchanger. 
     
     
         4 . The water heater of  claim 3 , wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket. 
     
     
         5 . The water heater of  claim 3 , further comprising a compressor fluidly connected to the condenser heat exchanger and the natural convection evaporator heat exchanger. 
     
     
         6 . The water heater of  claim 5 , wherein the compressor is at least one of a reciprocating compressor or a scroll compressor. 
     
     
         7 . The water heater of  claim 5 , further comprising an outer casing surrounding the insulation jacket. 
     
     
         8 . The water heater of  claim 7 , wherein the compressor is located outside the outer casing. 
     
     
         9 . The water heater of  claim 7 , wherein the compressor is located inside the outer casing. 
     
     
         10 . The water heater of  claim 5 , wherein the compressor is located inside a compressor jacket. 
     
     
         11 . The water heater of  claim 1 , wherein the natural convection evaporator heat exchanger is a roll-bonded type evaporator. 
     
     
         12 . The water heater of  claim 1 , wherein the natural convection evaporator heat exchanger is a micro-channel type heat exchanger. 
     
     
         13 . The water heater of  claim 1 , wherein the condenser heat exchanger is at least one of a coil-wrapped type heat exchanger, a roll-bonded type heat exchanger, or a micro-channel type heat exchanger. 
     
     
         14 . The water heater of  claim 1 , further comprising a condensate collector tray located below the water tank. 
     
     
         15 . A water heater, comprising:
 an outer casing;   a water tank disposed within the outer casing, wherein the water tank comprises a bottom wall, a top wall, and a side wall extending between and connected to the bottom wall and the top wall;   a condenser heat exchanger surrounding at least a portion of the side wall;   an insulation jacket disposed around at least the side wall and the condenser heat exchanger between the side wall and the outer casing;   a natural convection evaporator heat exchanger disposed about the insulation jacket; and   a compressor fluidly connected to the condenser heat exchanger and the natural convection evaporator heat exchanger,   wherein the water heater does not employ a fan to direct air to the natural convection evaporator heat exchanger.   
     
     
         16 . The water heater of  claim 15 , wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket. 
     
     
         17 . The water heater of  claim 15 , wherein the natural convection evaporator heat exchanger is a micro-channel type heat exchanger. 
     
     
         18 . The water heater of  claim 15 , further comprising a condensate collector tray located below the bottom wall. 
     
     
         19 . A method of heating water using a heat pump water heater, the method comprising:
 positioning a condenser heat exchanger about at least a portion of a side wall of a water tank;   positioning an insulation jacket about at least the side wall and the condenser heat exchanger;   positioning a natural convection evaporator heat exchanger about the insulation jacket;   connecting a compressor to the condenser heat exchanger and the natural convection evaporator heat exchanger; and   exchanging heat, by the natural convection evaporator heat exchanger, with ambient air using natural convection and without an air movement device to direct air to the natural convection evaporator heat exchanger.   
     
     
         20 . The method of  claim 17 , wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket.