System and Method for Using an Electronic Expansion Valve to Control a Discharge Pressure in a Multi-Purpose HVAC System

Abstract

A method for using an electronic expansion device in a system for heating water and conditioning an interior space by operating a first controller to monitor the operating discharge pressure from the compressor; and operating the first controller to produce a signal designating expansion of an orifice within the electronic expansion valve when the operating discharge pressure is greater than or equal to a predetermined pressure value.

What is claimed is: 
     
         1 . A method for using an electronic expansion device to control an operating discharge pressure in a multi-purpose HVAC system including an outdoor unit assembly, the outdoor unit assembly including an electronic expansion valve, a compressor and a first controller, operably coupled to a water heater module, the water heater module including at least one valve, the multi-purpose HVAC system further, the method comprising the steps of:
 (a) operating the multi-purpose HVAC system in a water heating mode;   (b) operating the first controller to monitor the operating discharge pressure from the compressor; and   (c) operating the first controller to produce a signal designating expansion of an orifice within the electronic expansion valve when the operating discharge pressure is greater than or equal to a predetermined pressure value.   
     
     
         2 . The method of  claim 1 , further comprising:
 (d) operating the first controller to remove the signal designating expansion of the orifice within the electronic expansion valve when the operating discharge pressure is less than the predetermined pressure value.   
     
     
         3 . The method of  claim 1 , further comprising:
 (d) operating the first controller to remove the signal designating expansion of the orifice within the electronic expansion valve when the multi-purpose HVAC system stops operating in a water heating mode.   
     
     
         4 . The method of  claim 1 , further comprising:
 (d) operating the first controller to remove the signal designating expansion of the orifice within the electronic expansion valve when the orifice reaches a maximum opening size.   
     
     
         5 . The method of  claim 1 , wherein the at least one valve comprises a pair of three way valves. 
     
     
         6 . The method of  claim 1 , wherein step (a) comprises a second controller operating one or more of the at least one valves to configure at least one refrigerant circuit. 
     
     
         7 . The method of  claim 6 , wherein the at least one valve comprises:
 a first valve coupled to an inlet of a heat exchanger via a first conduit;   a second valve coupled to an outlet of the heat exchanger via a second conduit;   a third valve coupled to the first valve via a third conduit;   a fourth valve coupled to the second valve via a fourth conduit;   wherein step (a) comprises opening the first and second valves and closing the third and fourth valves.   
     
     
         8 . The method of  claim 6 , wherein the at least one refrigerant circuit circulates a refrigerant from the outdoor unit assembly, through the water heater module, and returns to the outdoor unit assembly. 
     
     
         9 . A multi-purpose HVAC system comprising
 an outdoor unit assembly including a first controller, a compressor, and an electronic expansion valve;   an indoor unit assembly;   a water heater module including at least one valve, a heat exchanger, and a second controller; and   a plurality of conduits operatively coupling the water heater module to the outdoor unit assembly and the indoor unit assembly;   wherein the first controller is configured to:   (a) operate the multi-purpose HVAC system in a water heating mode;   (b) monitor the operating discharge pressure from the compressor; and   (c) produce a signal designating expansion of an orifice within the electronic expansion valve when the operating discharge pressure is greater than or equal to a predetermined pressure value.   
     
     
         10 . The multi-purpose HVAC system of  claim 9 , wherein the at least one valve comprises a pair of three way valves. 
     
     
         11 . The multi-purpose HVAC system of  claim 9 , wherein step (a) comprises the second controller operating one or more of the at least one valves to configure at least one refrigerant circuit to circulate a refrigerant from the outdoor unit assembly through the water heater module, and returns to the outdoor unit assembly. 
     
     
         12 . The multi-purpose HVAC system of  claim 11 , wherein the at least one valve comprises:
 a first valve;   a first conduit coupling the first valve to an inlet of the heat exchanger;   a second valve;   a second conduit coupling the second valve to an outlet of the heat exchanger;   a third valve;   a third conduit coupling the third valve to the first valve;   a fourth valve;   a fourth conduit coupling the fourth valve to the second valve;   wherein the second controller is configured to open the first and second valves and close the third and fourth valves to configure the at least one refrigerant circuit.   
     
     
         13 . The multi-purpose HVAC system of  claim 9 , wherein the first controller is configured to remove the signal designating expansion of the orifice within the electronic expansion valve when the operating discharge pressure is less than the predetermined pressure value. 
     
     
         14 . The multi-purpose HVAC system of  claim 9 , wherein the first controller is configured to remove the signal designating expansion of the orifice within the electronic expansion valve when the multi-purpose HVAC system stops operating in a water heating mode. 
     
     
         15 . The multi-purpose HVAC system of  claim 9 , wherein the first controller is configured to remove the signal designating expansion of the orifice within the electronic expansion valve when the orifice reaches its maximum opening size.