Providing domestic hot water from conventional residential split system heat pumps

Abstract

In a split system heat pump cooling and heating system, an auxiliary hot water storage tank is provided as an energy storage bank. Two sets of coils run through this storage tank, a first set carrying hot refrigerant from the heat pump to deposit energy and a second set carrying hot potable water to remove energy. Valve and switch matrixes are operated at the heat pump to provide hot potable water from the energy storage bank during both normal space heating and cooling operations of the heat pump.

What is claimed is: 
     
         1 . A hot water tank associated with a heat pump for storing hot water therein comprising:
 a polymer water storage tank having two intertwined coils therein including a first coil carrying potable water to be heated and a second coil carrying hot refrigerant from a heat pump thereby maintaining heat in hot water of the hot water tank whereby heated hot water in the tank from the second coil maintains heat in the first coil.   
     
     
         2 . The apparatus of  claim 1  wherein the hot water tank has an upper portion and a lower portion with the upper portion having an air-filled bladder that expands and contracts in response to water temperature in the tank. 
     
     
         3 . The apparatus of  claim 2  wherein ends of the intertwined coils emerge from the hot water tank from the upper portion thereof. 
     
     
         4 . The apparatus of  claim 1  wherein the intertwined coils are separated from each other by spacers. 
     
     
         5 . The apparatus of  claim 1  wherein one of the intertwined coils is wound more tightly at a first end and less tightly at an opposite end and the second of the intertwined coils is wound in a reverse manner being less tightly wound where the first coil is more tightly wound and more tightly wound where the first coil is less tightly wound. 
     
     
         6 . The apparatus of  claim 1  wherein water stored in the hot water tank is chemically treated for metal preservation. 
     
     
         7 . The apparatus of  claim 1  wherein the hot water tank has an outer spiral wound sheet metal skin. 
     
     
         8 . An unpressurized hot water tank having an upper portion and a lower portion, the lower portion storing hot water therein serving as a thermal store, the upper portion having an air-filled bladder that expands and contracts in response to water temperature in the tank, the hot water tank further having a tank thermostat set to a specified tank temperature range and two intertwined tank coils therein including a first tank coil carrying potable water to be heated from the thermal store and a second tank coil carrying hot refrigerant from a compressor as needed to maintain the specified tank temperature range in the stored hot water of the hot water tank. 
     
     
         9 . The apparatus of  claim 8  wherein water stored in the hot water tank is chemically treated for metal preservation. 
     
     
         10 . The apparatus of  claim 8  wherein the hot water tank has an outer spiral wound sheet metal skin. 
     
     
         11 . The apparatus of  claim 10  wherein the hot water tank has an inner plastic shell in contact with the stored hot water. 
     
     
         12 . The apparatus of  claim 11  wherein the hot water tank has foam insulation between the sheet metal skin and the plastic shell. 
     
     
         13 . The apparatus of  claim 8  wherein the hot water tank has a lid communicating atmospheric pressure to water in the tank.