Geothermal system for heating water

Abstract

A system and method for heating water with heat obtained from liquid that is sourced by a ground-loop system, the system including a ground-loop heat exchanger, a compressor, a hot-water-reservoir-loop heat exchanger, a subcooler heat exchanger, and a thermostatic expansion valve. The ground-loop heat exchanger is structured to transfer heat from heated ground liquid to a refrigerant. The compressor is structured to increase a pressure of the refrigerant received from the ground-loop heat exchanger. The hot-water-reservoir-loop heat exchanger is structured to transfer heat from the refrigerant to water received from the hot-water reservoir. The subcooler heat exchanger is structured to transfer heat from the refrigerant to the ground liquid before returning the liquid to the ground-loop system, and the thermostatic expansion valve structured to control a flow of the refrigerant to the ground-loop heat exchanger.

1 . A system for heating water that is used to heat water in a hot-water reservoir with heat obtained from liquid that is sourced by a ground-loop system, the system for heating water comprising:
 a ground-loop heat exchanger configured to receive a liquid from the ground-loop system that geothermally heats the liquid and to transfer heat from the liquid to a refrigerant;   a compressor coupled to the ground-loop heat exchanger and configured to increase a pressure of the refrigerant received from the ground-loop heat exchanger;   a hot-water-reservoir-loop heat exchanger coupled to the compressor and to the hot-water reservoir and configured to receive the refrigerant and transfer heat from the refrigerant to water received from the hot-water reservoir;   a subcooler heat exchanger coupled to the hot-water-reservoir-loop heat exchanger and to the ground-loop system and configured to receive the liquid from the ground-loop heat exchanger and the refrigerant from the hot-water-reservoir-loop exchanger and to transfer heat from the refrigerant to the liquid before returning the liquid to the ground-loop system; and   a thermostatic expansion valve coupled between the subcooler heat exchanger and the ground-loop heat exchanger and configured to control a flow of the refrigerant from the subcooler heat exchanger to the ground-loop heat exchanger.   
     
     
         2 . The system of  claim 1 , further comprising a suction line accumulator coupled between the compressor and the ground-loop heat exchanger and configured to control a flow of the refrigerant into the compressor from the ground-loop heat exchanger. 
     
     
         3 . The system of  claim 1 , further comprising a circulation pump coupled between the ground-loop heat exchanger and the ground loop system and configured to circulate the liquid from the ground loop system through the ground-loop heat exchanger and through the subcooler heat exchanger prior to returning the liquid to the ground loop system. 
     
     
         4 . The system of  claim 1 , further comprising a circulation pump coupled between the ground-loop heat exchanger and the subcooler heat exchanger and configured to circulate the liquid from the ground-loop heat exchanger through the subcooler heat exchanger and through the ground loop system prior to the liquid returning to the ground-loop heat exchanger. 
     
     
         5 . The system of  claim 1 , further comprising a circulation pump coupled between the subcooler heat exchanger and the ground loop system and configured to circulate the liquid from the subcooler heat exchanger through the ground loop system and through the ground-loop heat exchanger prior to the liquid returning to the subcooler heat exchanger. 
     
     
         6 . The system of  claim 1 , further comprising a circulation pump coupled between the hot-water-reservoir-loop heat exchanger and the hot-water reservoir and configured to circulate the water from the hot-water reservoir through the hot-water-reservoir-loop heat exchanger prior to returning the water to the hot-water reservoir. 
     
     
         7 . The system of  claim 1 , wherein the ground loop system includes a plurality of pipes that are arranged in the Earth to enable the transfer of heat from the Earth to the liquid. 
     
     
         8 . The system of  claim 1 , wherein the liquid is water. 
     
     
         9 . The system of  claim 1 , wherein the hot-water-reservoir-loop heat exchanger receives the refrigerant in a cooled, low-pressure gaseous state and outputs the refrigerant in a warmed, low-pressure gaseous state. 
     
     
         10 . The system of  claim 1 , wherein the subcooler heat exchanger receives the liquid from the ground-loop heat exchanger at a temperature that is colder than the water that is received from the ground loop system, and wherein the liquid output from the subcooler heat exchanger is warmer than the liquid received from the ground-loop heat exchanger. 
     
     
         11 . The system of  claim 1 , wherein the subcooler heat exchanger outputs the refrigerant at a temperature that is colder than the temperature of the refrigerant received by the subcooler heat exchanger. 
     
     
         12 . A system for heating water in a hot-water reservoir, comprising:
 a ground-loop heat exchanger configured to exchange heat from geothermally heated liquid sourced from a ground-loop system to a refrigerant;   a compressor in fluid communication with the ground-loop heat exchanger, the compressor configured to increase a pressure of the refrigerant;   a hot-water-reservoir-loop heat exchanger in fluid communication with the compressor, the hot-water-reservoir-loop heat exchanger configured to exchange heat from the refrigerant to the water received from the hot-water reservoir;   a subcooler heat exchanger in fluid communication with the hot-water-reservoir-loop heat exchanger and the ground-loop system, the subcooler heat exchanger configured to exchange heat from the refrigerant to the liquid received from the ground-loop heat exchanger before returning the liquid to the ground-loop system; and   a thermostatic expansion valve in fluid communication with the subcooler heat exchanger, the thermostatic expansion valve configured to control a flow of the refrigerant to the ground-loop heat exchanger.   
     
     
         13 . The system of  claim 12 , further comprising a suction line accumulator in fluid communication with the ground-loop heat exchanger and the compressor, the suction line accumulator configured to control a flow of the refrigerant into the compressor. 
     
     
         14 . The system of  claim 12 , further comprising a circulation pump in fluid communication with the ground loop system, the circulation pump configured to circulate the liquid through the ground loop system, the ground-loop heat exchanger, and the subcooler heat exchanger. 
     
     
         15 . The system of  claim 12 , further comprising a circulation pump in fluid communication with the hot-water reservoir, the circulation pump configured to circulate the water from the hot-water reservoir through the hot-water-reservoir-loop heat exchanger and back to the hot-water reservoir. 
     
     
         16 . The system of  claim 12 , wherein the ground loop system includes a plurality of pipes that are in fluid communication with the ground-loop heat exchanger and the subcooler heat exchanger, the plurality of pipes are configured to enable the transfer of heat from the Earth to the liquid. 
     
     
         17 . A method for heating a first liquid in a hot-liquid reservoir, comprising:
 receiving a second liquid from a ground-loop system that geothermally heats the second liquid;   transferring heat from the second liquid to a third liquid by a ground-loop heat exchanger to increase a first temperature of the third liquid to a second temperature of the third liquid;   compressing the third liquid by a compressor to increase a pressure and temperature of the third liquid from the second temperature to a third temperature of the third liquid;   transferring heat from the third liquid to the first liquid by a hot-water-reservoir-loop heat exchanger to increase a temperature of the first liquid and reduce the third temperature of the third liquid to a fourth temperature of the third liquid;   transferring heat from the third liquid to the second liquid by a subcooler heat exchanger prior to returning the second liquid to the ground-loop system to reduce the fourth temperature of the third liquid to a fifth temperature of the third liquid; and   reducing the pressure of the third liquid by a thermostatix expansion valve to reduce the fifth temperature of the third liquid to the first temperature of the third liquid prior to the transferring of heat from the second liquid to the third liquid.   
     
     
         18 . The method of  claim 17 , wherein third liquid at the first temperature is in a cooled, low-pressure gaseous state and the third liquid at the second temperature is in a warmed, low-pressure gaseous state. 
     
     
         19 . The method of  claim 17 , wherein the third liquid at the fifth temperature is colder than third liquid at the fourth temperature.