Indoor Liquid/Suction Heat Exchanger

Abstract

Systems and methods are disclosed that include providing an air conditioning (A/C) system having an indoor unit with a Liquid/Suction Heat Exchanger (LSHX) coupled between an outdoor heat exchanger of an outdoor unit and an indoor metering device on a so-called “liquid” line and coupled between an indoor heat exchanger and a compressor of the outdoor unit on a so-called “vapor” line. The LSHX is configured to increase the efficiency of the A/C system by increasing the amount of subcooling in the refrigerant on the liquid line of the LSHX and increasing the amount of superheat in the refrigerant on the vapor line of the LSHX.

What is claimed is: 
     
         1 . An indoor unit of an air conditioning (A/C) system, comprising:
 a liquid/suction heat exchanger (LSHX); and   a superheat sensor configured to monitor the amount of superheat in refrigerant exiting the LSHX.   
     
     
         2 . The indoor unit of  claim 1 , further comprising:
 an indoor metering device configured to control the amount of superheat in the refrigerant exiting the LSHX in response to the superheat sensor monitoring the amount of superheat in the refrigerant exiting the LSHX.   
     
     
         3 . The indoor unit of  claim 2 , further comprising:
 an indoor metering device controller configured to control the position of the indoor metering device to control the amount of superheat in the refrigerant exiting the LSHX.   
     
     
         4 . The indoor unit of  claim 1 , wherein the LSHX is configured to increase an amount of subcooling in refrigerant received via a liquid line from an outdoor heat exchanger of an outdoor unit. 
     
     
         5 . The indoor unit of  claim 1 , wherein the LSHX is configured to increase an amount of superheat in refrigerant received from an indoor heat exchanger of the indoor unit. 
     
     
         6 . The indoor unit of  claim 1 , wherein the LSHX is configured to prevent liquid-phase refrigerant from entering a compressor of the outdoor unit. 
     
     
         7 . A heating, ventilation, and/or air condition (A/C) system, comprising:
 an outdoor unit; and   an indoor unit, comprising:
 a liquid/suction heat exchanger (LSHX); and 
 a superheat sensor configured to monitor the amount of superheat in refrigerant exiting the LSHX. 
   
     
     
         8 . The A/C system of  claim 7 , wherein the indoor unit comprises an indoor metering device configured to control the amount of superheat in the refrigerant exiting the LSHX in response to the superheat sensor monitoring the amount of superheat in the refrigerant exiting the LSHX. 
     
     
         9 . The A/C system of  claim 8 , wherein the indoor unit comprises an indoor metering device controller configured to control the position of the indoor metering device to control the amount of superheat in the refrigerant exiting the LSHX. 
     
     
         10 . The A/C system of  claim 7 , wherein the LSHX is coupled between an outdoor heat exchanger of the outdoor unit and an indoor metering device of the indoor unit via a liquid line of the LSHX. 
     
     
         11 . The A/C system of  claim 10 , wherein the LSHX is configured to receive subcooled refrigerant from the heat exchanger of the outdoor unit through the liquid line. 
     
     
         12 . The A/C system of  claim 11 , wherein the LSHX is configured to increase the amount of subcooling in the refrigerant received from the heat exchanger of the outdoor unit through the liquid line. 
     
     
         13 . The A/C system of  claim 12 , wherein the LSHX is configured to increase the amount of subcooling in the refrigerant by at least about 5 degrees Fahrenheit. 
     
     
         14 . The A/C system of  claim 7 , wherein the LSHX is coupled between an indoor heat exchanger of the indoor unit and a compressor of the outdoor unit via a vapor line of the LSHX. 
     
     
         15 . The A/C system of  claim 14 , wherein the LSHX is configured to receive superheated refrigerant from the indoor heat exchanger of the indoor unit through the vapor line. 
     
     
         16 . The A/C system of  claim 15 , wherein the LSHX is configured to increase the amount of superheat in the refrigerant received from the indoor heat exchanger of the indoor unit through the vapor line. 
     
     
         17 . The A/C system of  claim 16 , wherein the LSHX is configured to prevent liquid-phase refrigerant from entering the compressor of the outdoor unit. 
     
     
         18 . The A/C system of  claim 7 , wherein the A/C system comprises a reversible heating, ventilation, and/or air conditioning (HVAC) heat pump system. 
     
     
         19 . A method of operating a heating, ventilation, and/or air condition (A/C) system, comprising:
 providing an A/C system comprising an outdoor unit and an indoor unit comprising an indoor metering device and a liquid/suction heat exchanger (LSHX);   operating the A/C system in a cooling mode;   monitoring the amount of superheat in refrigerant exiting the LSHX; and   controlling a position of the indoor metering device to control the amount of superheat in the refrigerant exiting the LSHX.   
     
     
         20 . The method of  claim 19 , further comprising:
 increasing the amount of subcooling in the refrigerant by passing the refrigerant through a liquid line of the LSHX; and   increasing the amount of superheat in the refrigerant by passing the refrigerant through a vapor line of the LSHX.