Swimming Pool or Spa Heat Pump With Refrigerant Charge Compensator and Method of Operating Same

Abstract

A swimming pool or spa heat pump operable in cooling and heating modes, along with a method of operating same is disclosed. The heat pump includes a compressor, first and second heat exchangers, refrigerant charge compensator, and at least one means for lowering the pressure of refrigerant provided to the first and second heat exchangers. The first heat exchanger is configured to transfer thermal energy to and/or extract thermal energy from a first fluid, and the second heat exchanger is configured to transfer thermal energy to and/or extract thermal energy from pool or spa water. The refrigerant charge compensator is configured to reduce an amount of active refrigerant charge in circulation in the heat pump when the heat pump is operated in the cooling mode and increase the amount of active refrigerant charge in circulation when the heat pump is operated in the heating mode.

What is claimed is: 
     
         1 . A swimming pool or spa heat pump capable of operating in a cooling mode of operation and a heating mode of operation, comprising:
 a compressor;   a first heat exchanger configured to transfer thermal energy to and/or extract thermal energy from a first fluid;   a second heat exchanger configured to transfer thermal energy to and/or extract thermal energy from a second fluid, the second fluid being pool or spa water;   at least one means for lowering the pressure of refrigerant being provided to the first heat exchanger when the heat pump is operated in the heating mode of operation and lowering the pressure of refrigerant being provided to the second heat exchanger when the heat pump is operated in the cooling mode of operation; and   a refrigerant charge compensator configured to reduce an amount of active refrigerant charge in circulation in the heat pump when the heat pump is operated in the cooling mode of operation and increase the amount of active refrigerant charge in circulation in the heat pump when the heat pump is operated in the heating mode of operation.   
     
     
         2 . The swimming pool or spa heat pump of  claim 1 , comprising:
 a reversing valve fluidly coupled with the compressor, the first heat exchanger, and the second heat exchanger, the reversing valve configured to receive pressurized refrigerant from the compressor, direct the pressurized refrigerant to the first heat exchanger when the heat pump is in the cooling mode of operation, and direct the pressurized refrigerant to the second heat exchanger when the heat pump is in the heating mode of operation,   wherein the refrigerant charge compensator is positioned between the second heat exchanger and the reversing valve.   
     
     
         3 . The swimming pool or spa heat pump of  claim 1 , wherein the refrigerant charge compensator is configured to (1) cause refrigerant to be removed from circulation when the heat pump is operated in the cooling mode of operation and store the removed refrigerant, and (2) cause refrigerant stored by the refrigerant charge compensator to reenter circulation when the heat pump is operated in the heating mode of operation. 
     
     
         4 . The swimming pool or spa heat pump of  claim 1 , wherein the first heat exchanger is a microchannel coil heat exchanger. 
     
     
         5 . The swimming pool or spa heat pump of  claim 1 , wherein said at least one means includes an expansion valve assembly. 
     
     
         6 . The swimming pool or spa heat pump of  claim 1 , wherein the first heat exchanger has a lower heat transfer flux than the second heat exchanger. 
     
     
         7 . The swimming pool or spa heat pump of  claim 1 , wherein the refrigerant charge compensator is configured to (1) cause refrigerant to be removed from circulation when low-temperature refrigerant flows through the refrigerant charge compensator, and (2) cause refrigerant to renter circulation when high-temperature refrigerant flows through the refrigerant charge compensator. 
     
     
         8 . The swimming pool or spa heat pump of  claim 1 , wherein the refrigerant charge compensator includes a chamber in fluidic communication with a liquid refrigerant line of the heat pump. 
     
     
         9 . The swimming pool or spa heat pump of  claim 8 , wherein the liquid refrigerant line extends between the first heat exchanger and the at least one means for lowering the pressure of refrigerant. 
     
     
         10 . The swimming pool or spa heat pump of  claim 1 , comprising an accumulator configured to receive low-pressure, low-temperature refrigerant. 
     
     
         11 . A method of operating a heat pump capable of operating in a cooling mode of operation and a heating mode of operation, comprising:
 increasing the pressure of refrigerant with a compressor to generate high-pressure, high-temperature refrigerant;   causing the high-pressure, high-temperature refrigerant to flow through a first heat exchanger and transfer thermal energy to a first fluid;   reducing the pressure and the temperature of the high-pressure, high-temperature refrigerant to generate low-pressure, low-temperature refrigerant;   causing the low-pressure, low-temperature refrigerant to flow through a second heat exchanger and extract thermal energy from a second fluid, the second fluid being pool or spa water;   causing the low-pressure, low-temperature refrigerant to flow through a refrigerant charge compensator after flowing through the second heat exchanger, the refrigerant charge compensator positioned between the second heat exchanger and a reversing valve;   reducing an amount of active refrigerant charge in circulation in the heat pump with the refrigerant charge compensator; and   returning the low-pressure, low-temperature refrigerant to the compressor.   
     
     
         12 . The method of  claim 11 , comprising the steps of:
 increasing the pressure of the low-pressure, low-temperature refrigerant returned to the compressor to generate high-pressure, high-temperature refrigerant;   causing the high-pressure, high-temperature refrigerant to flow through the refrigerant charge compensator;   increasing the amount of active refrigerant charge in circulation in the heat pump with the refrigerant charge compensator;   causing the high-pressure, high-temperature refrigerant to flow through the second heat exchanger and transfer thermal energy to the second fluid;   reducing the pressure and the temperature of the high-temperature refrigerant to generate low-pressure, low-temperature refrigerant;   causing the low-pressure, low-temperature refrigerant to flow through the first heat exchanger; and   returning the low-pressure, low-temperature refrigerant to the compressor.   
     
     
         13 . The method of  claim 12 , comprising:
 causing, with the refrigerant charge compensator, refrigerant to be removed from circulation when the heat pump is operated in a cooling mode of operation and storing the removed refrigerant; and   causing refrigerant stored by the refrigerant charge compensator to reenter circulation when the heat pump is operated in a heating mode of operation.   
     
     
         14 . The method of  claim 11 , wherein the first heat exchanger is a microchannel coil heat exchanger. 
     
     
         15 . The method of  claim 11 , wherein the refrigerant charge compensator includes a chamber in fluidic communication with a liquid refrigerant line of the heat pump. 
     
     
         16 . The method of  claim 15 , wherein the liquid refrigerant line extends between the first heat exchanger and at least one means for lowering the pressure of refrigerant. 
     
     
         17 . The method of  claim 11 , wherein the first heat exchanger has a lower heat transfer flux than the second heat exchanger. 
     
     
         18 . The method of  claim 11 , comprising:
 causing refrigerant to be removed from circulation when low-temperature refrigerant flows through the refrigerant charge compensator; and   causing refrigerant to reenter circulation when the high-temperature refrigerant flows through the refrigerant charge compensator.   
     
     
         19 . A swimming pool or spa heat pump capable of operating in a cooling mode of operation and a heating mode of operation, comprising:
 a housing;   a compressor;   a first heat exchanger configured to transfer thermal energy to and extract thermal energy from ambient air, the first heat exchanger being a microchannel heat exchanger;   a fan configured to blow ambient air across the first heat exchanger;   a second heat exchanger configured to transfer thermal energy to and extract thermal energy from pool or spa water;   a reversing valve fluidly coupled with the compressor, the first heat exchanger, and the second heat exchanger, the reversing valve being configured to receive pressurized refrigerant from the compressor, direct the pressurized refrigerant to the first heat exchanger when the heat pump is in the cooling mode of operation, and direct the pressurized refrigerant to the second heat exchanger when the heat pump is in the heating mode of operation;   at least one means for lowering the pressure of refrigerant being provided to the first heat exchanger when the heat pump is operated in the heating mode of operation and lowering the pressure of refrigerant being provided to the second heat exchanger when the heat pump is operated in the cooling mode of operation; and   a refrigerant charge compensator having a chamber in fluidic communication with a refrigerant line at a position between the first heat exchanger and the second heat exchanger, the refrigerant charge compensator being configured to (1) cause refrigerant to be removed from circulation and stored in the chamber to reduce an amount of active refrigerant charge in circulation in the heat pump when the heat pump is operated in the cooling mode of operation and (2) cause refrigerant stored in the chamber to reenter circulation to increase the amount of active refrigerant charge in circulation in the heat pump when the heat pump is operated in the heating mode of operation,   wherein the first heat exchanger has a lower heat transfer flux than the second heat exchanger.   
     
     
         20 . The swimming pool or spa heat pump of  claim 19  in combination with a swimming pool filtration pump for circulating the pool or spa water through the second heat exchanger.