Heat pump water heater

Abstract

A heat pump water heater employing a thermostatic mixing valve integrated with the water lines carrying water from a water tank to a heat pump and then back to the water tank to achieve one pass technology to heat the water quickly and to achieve rapid recovery time without the use of supplemental heating sources.

I claim: 
     
         1 . A heat pump water heater to be used with a pressurized water tank, said heat pump water heater comprising a heat pump, refrigerant piping, water piping, a heat exchanger, a thermostatic mixing valve, and a circulating pump,
 wherein the heat pump is configured to transfer heat energy to refrigerant circulated within the refrigerant piping,   the water piping is comprised of inflow piping, outflow piping, and circulation piping, wherein the circulation piping is interposed between the inflow piping and the outflow piping, the inflow piping is connected to a lower portion of the water tank and configured to allow water to pass out of the water tank and into the circulation piping, and the outflow piping is connected to an upper portion of the water tank and configured to allow water to pass out of the circulation piping and into the water tank,   a portion of the refrigerant piping and a portion of the circulation piping are integrated with the heat exchanger, such that heat energy from the refrigerant contained within the refrigerant piping is transferred to water contained within the circulation piping via the heat exchanger,   the thermostatic mixing valve is located at a junction of the inflow piping and the circulation piping, with the inflow piping connected to a cold water inlet of the thermostatic mixing valve, one end of the circulation piping connected to a hot water inlet of the thermostatic mixing valve, and another end of the circulation piping connected to a mixed water outlet of the thermostatic mixing valve,   the circulating pump is located inline of the circulation piping between the mixed water outlet of the thermostatic mixing valve and the heat exchanger and is configured to circulate water contained within the water piping, and   the outflow piping is connected to the circulation piping by a T-junction located at a location between the heat exchanger and the hot water inlet of the thermostatic mixing valve;   whereby the thermostatic mixing valve is configured to allow a variable quantity of water, including no water, to flow from the water tank to the heat exchanger, and to allow a variable quantity of water within the circulation piping to flow to the heat exchanger.   
     
     
         2 . The heat pump water heater of  claim 1  wherein the thermostatic mixing valve is adjustable to accommodate a desired temperature of the water contained within the circulation piping. 
     
     
         3 . The heat pump water heater of  claim 1  wherein the thermostatic mixing valve has a closed state and an opened state, whereby when the thermostatic mixing valve is in the closed state no water enters the circulation piping through the cold water inlet of the thermostatic mixing valve, and when the thermostatic mixing valve is in the opened state water enters the circulation piping through the cold water inlet of the thermostatic mixing valve. 
     
     
         4 . The heat pump water heater of  claim 3  wherein the heat pump water heater has a priming cycle, whereby during the priming cycle the thermostatic mixing valve is in the closed state, the heat pump is activated, and the circulating pump is activated, such that the heat pump causes heat energy to be transferred to the refrigerant in the refrigerant piping, and the circulating pump causes water located within the circulation piping to circulate within the circulation piping and to flow through the heat exchanger to absorb heat energy from the refrigerant. 
     
     
         5 . The heat pump water heater of  claim 3  wherein the heat pump water heater has an operating cycle, whereby during the operating cycle the thermostatic mixing valve is in the opened state, the heat pump is activated, and the circulating pump is activated, such that water flows from the water tank through the inflow piping into the circulation piping, the heat pump causes heat energy to be transferred to the refrigerant in the refrigerant piping, the circulating pump causes water located within the circulation piping to circulate within the circulation piping and to flow through the heat exchanger to absorb heat energy from the refrigerant, and water flows into the water tank through the outflow piping. 
     
     
         6 . The heat pump water heater of  claim 1  wherein the heat pump water heater further comprises a temperature probe located within the water tank proximate to a bottom of the water tank. 
     
     
         7 . The heat pump water heater of  claim 6  wherein
 the thermostatic mixing valve has an opened state, whereby when the thermostatic mixing valve is in the opened state water enters the circulation piping through the cold water inlet of the thermostatic mixing valve; 
 the heat pump water heater has an operating cycle, whereby during the operating cycle the thermostatic mixing valve is in the opened state, the heat pump is activated, and the circulating pump is activated, such that water flows from the water tank through the inflow piping into the circulation piping, the heat pump causes heat energy to be transferred to the refrigerant in the refrigerant piping, the circulating pump causes water located within the circulation piping to circulate within the circulation piping and to flow through the heat exchanger to absorb heat energy from the refrigerant, and water flows into the water tank through the outflow piping; and 
 the temperature probe determines the temperature of the water located in the water tank at the bottom of the water tank, and activates the operating cycle of the heat pump water heater when said temperature of said water is below a desired temperature, and deactivates the operating cycle of the heat pump water heater when said temperature of said water reaches the desired temperature.