Low-cost heat pump water heater

Abstract

An improved heat pump water heater of the type having a water tank with an exterior surface and defining a water chamber, a top on the water tank with at least one opening therethrough in communication with the water chamber, and a heat pump of the type having a compressor, the compressor being in fluid communication with an annular condenser assembly via a first refrigerant conduit, the annular condenser assembly being in fluid communication with an expansion device through a second refrigerant conduit, the expansion device being in fluid communication with an evaporator through a third refrigerant conduit, the evaporator being in fluid communication with the compressor through a fourth refrigerant conduit and control means therefore, the improvement comprising disposing the annular condenser assembly through the opening in the top of the water tank and into the water chamber, the water tank opening further comprising a geometric twisted sleeve positioned to form a helical insertion pattern in the annular condenser assembly, the annular condenser assembly further comprising an elongate outer tube having a closed bottom end and an open and opposed upper end in flow communication with the first refrigerant conduit, an elongate return tube disposed within the outer tube and having an open bottom end and a closed and opposed top end in flow communication with the second refrigerant conduit, an elongate capillary tube disposed within the return tube and having an open bottom end and an open and opposed top end in flow communication with the second refrigerant conduit, and an air gap disposed between the capillary tube and the return tube.

1 . An improved heat pump water heater of the type having a water tank with an exterior surface and defining a water chamber, a top on the water tank with at least one opening therethrough in communication with the water chamber, and a heat pump of the type having a compressor, the compressor being in fluid communication with an annular condenser assembly via a first refrigerant conduit, the annular condenser assembly being in fluid communication with an expansion device through a second refrigerant conduit, the expansion device being in fluid communication with an evaporator through a third refrigerant conduit, the evaporator being in fluid communication with the compressor through a fourth refrigerant conduit and control means therefore, the improvement comprising: 
 disposing the annular condenser assembly through the opening in the top of the water tank and into the water chamber, the water tank opening further comprising a geometric twisted sleeve positioned to form a helical insertion pattern in the annular condenser assembly, the annular condenser assembly further comprising: 
 an elongate outer tube having a closed bottom end and an open and opposed upper end in flow communication with the first refrigerant conduit,  
 an elongate return tube disposed within the outer tube and having an open bottom end and a closed and opposed top end in flow communication with the second refrigerant conduit,  
 an elongate capillary tube disposed within the return tube and having an open bottom end and an open and opposed top end in flow communication with the second refrigerant conduit, and  
 an air gap disposed between the capillary tube and the return tube.  
   
   
   
       2 . An improved heat pump water heater as claimed in  claim 1  wherein the first refrigerant conduit, the expansion device, and the second refrigerant conduit are disposed inside the water tank; the evaporator, the third refrigerant conduit, the compressor and the fourth refrigerant conduit and the control means are disposed on the water tank.  
   
   
       3 . An improved heat pump water heater as claimed in  claim 1  and further comprising a housing disposed on the top of the water tank and containing therein the compressor and evaporator.  
   
   
       4 . An improved heat pump water heater as claimed in  claim 1  wherein the annular condenser assembly is constructed of copper.  
   
   
       5 . An improved heat pump water heater as claimed in  claim 1  wherein the annular condenser assembly is constructed of a first metal and a second metal which is capable of corroding at a rate greater than the rate of corrosion of the first metal.  
   
   
       6 . An improved heat pump water heater as claimed in  claim 5  wherein the second metal is selected from the group consisting of aluminum, magnesium or zinc.  
   
   
       7 . An improved heat pump water heater as claimed in  claim 1  wherein the annular condenser assembly is a double walled helical device.  
   
   
       8 . An improved heat pump water heater as claimed in  claim 1  wherein the coefficient of performance is in the range of approximately 1.7 to 1.8.  
   
   
       9 . An improved heat pump water heater as claimed in  claim 1  wherein the control means further comprises a control module having a voltage divider network to energize heating sources.  
   
   
       10 . An improved heat pump water heater as claimed in  claim 9  having three heating sources.  
   
   
       11 . A method of constructing an improved heat pump water heater of the type having a water tank formed of a first metal and defining a water chamber, a top on the water tank with at least one opening therethrough for an anode rod to be disposed within the water chamber, and a heat pump of the type having a compressor, the compressor being in fluid communication with an annular condenser assembly via a first refrigerant conduit, the annular condenser assembly being in fluid communication with an expansion device through a second refrigerant conduit, the expansion device being in fluid communication with an evaporator through a third refrigerant conduit, the evaporator being in fluid communication with the compressor through a fourth refrigerant conduit and control means therefore, the comprising the steps of: 
 a. removing the anode rod from the water tank; and    b. inserting the annular condenser assembly through the opening in the top of the water tank and into the water chamber, the water tank opening further comprising a geometric twisted sleeve positioned to form a helical insertion pattern in the annular condenser assembly, the annular condenser assembly further comprising an elongate outer tube having a closed bottom end and an open and opposed upper end in flow communication with the first refrigerant conduit, an elongate return tube disposed within the outer tube and having an open bottom end and a closed and opposed top end in flow communication with the second refrigerant conduit, an elongate capillary tube disposed within the return tube and having an open bottom end and an open and opposed top end in flow communication with the second refrigerant conduit, and an air gap disposed between the capillary tube and the return tube.    
   
   
       12 . A method as claimed in  claim 11  wherein the annular condenser assembly is constructed of copper.  
   
   
       13 . A method as claimed in  claim 11  wherein the annular condenser assembly is constructed of a first metal and a second metal which is capable of corroding at a rate greater than the rate of corrosion of the first metal.  
   
   
       14 . A method as claimed in  claim 13  wherein the second metal is selected from the group consisting of aluminum, magnesium or zinc.  
   
   
       15 . A method as claimed in  claim 11  wherein the annular condenser assembly is a double walled helical device.  
   
   
       16 . A method as claimed in  claim 11  wherein the coefficient of performance is in the range of approximately 1.7 to 1.8.  
   
   
       17 . A method as claimed in  claim 11  wherein the control means further comprises a control module having a voltage divider network to energize multiple heating sources.  
   
   
       18 . A method as claimed in  claim 17  further comprising three heating sources.