Refrigerant circuit for cooling a vfd unit of an air conditioning system

Abstract

A refrigerant circuit for cooling a Variable Frequency Drive (VFD) unit of an air conditioning system includes a condenser for condensing refrigerant vapor. A heat sink includes a supply conduit assembly adapted to receive a first portion of a subcooled refrigerant fluid from the condenser and a discharge conduit assembly adapted to discharge a superheated refrigerant vapor to an accumulator. The subcooled refrigerant fluid transitions to the superheated refrigerant vapor upon absorbing heat from the VFD unit thermally coupled to the heat sink. The accumulator supplies the superheated refrigerant vapor to a compressor. An expansion valve expands a second portion of the condensed refrigerant fluid. An evaporator evaporates the expanded second portion of the refrigerant fluid. A compressor compresses the evaporated refrigerant vapor from the evaporator and the superheated refrigerant vapor received from the accumulator.

We claim: 
     
         1 . A refrigerant circuit for cooling a Variable Frequency Drive (VFD) unit of an air conditioning system, the refrigerant circuit comprising:
 a condenser for condensing refrigerant vapor;   a heat sink comprising a supply conduit assembly and a discharge conduit assembly, wherein the supply conduit assembly is adapted to receive a first portion of a subcooled refrigerant fluid from the condenser and the discharge conduit assembly is adapted to discharge a superheated refrigerant vapor to an accumulator, wherein the subcooled refrigerant fluid transitions to the superheated refrigerant vapor upon absorbing heat from the VFD unit thermally coupled to the heat sink;   the accumulator adapted to supply the superheated refrigerant vapor to a compressor;   an expansion valve for expanding a second portion of the condensed refrigerant fluid;   an evaporator for evaporating the expanded second portion of the refrigerant fluid; and   the compressor, for compressing the evaporated refrigerant vapor from the evaporator and the superheated refrigerant vapor received from the accumulator.   
     
     
         2 . The refrigerant circuit of  claim 1 , further comprising at least one valve for at least one of selectively preventing and selectively allowing flow of the first portion of the subcooled refrigerant fluid to the heat sink. 
     
     
         3 . The refrigerant circuit of  claim 1 , wherein the heat sink comprises:
 a base;   a plurality of heat passages defined in the base, each of the plurality of heat passages extending from an outlet defined proximal to a high temperature region of the base towards an inlet defined proximal to a low temperature region of the base, each of the plurality of heat passages comprising:
 at least one evaporator section proximal to the high temperature region; and 
 at least one condenser section proximal to the low temperature region and in fluid communication with the at least one evaporator section, wherein the subcooled refrigerant fluid in the at least one condenser section transitions to the superheated refrigerant vapor upon passing through the at least one evaporator section; 
   the supply conduit assembly adapted to be in fluid communication with a corresponding inlet of a heat passage from the plurality of heat passages; and   the discharge conduit assembly adapted to be in fluid communication with a corresponding outlet of a heat passage from the plurality of heat passages.   
     
     
         4 . The refrigerant circuit of  claim 1 , wherein the heat sink comprises:
 a base comprising:
 a first face; 
 a second face opposite to the first face; and 
 a plurality of fins disposed on the second face and extending from a high temperature region of the base; 
   a plurality of heat pipes thermally coupled to the base and extending from an outlet defined proximal to the high temperature region of the base towards an inlet defined proximal to a low temperature region of the base, each of the plurality of heat pipes comprising:
 at least one evaporator section proximal to the high temperature region; and 
 at least one condenser section proximal to the low temperature region and in fluid communication with the at least one evaporator section, wherein a subcooled refrigerant fluid in the at least one condenser section transitions to a superheated refrigerant vapor upon passing through the at least one evaporator section; 
   the supply conduit assembly adapted to be in fluid communication with a corresponding inlet of a heat pipe from the plurality of heat pipes; and   the discharge conduit assembly adapted to be in fluid communication with a corresponding outlet of a heat pipe from the plurality of heat pipes.   
     
     
         5 . The refrigerant circuit of  claim 1 , wherein the supply conduit assembly comprises:
 a first diverter element adapted to connect at least one first header conduit with a plurality of first branch conduits for supplying the subcooled refrigerant fluid, each of the plurality of first branch conduits adapted to be in fluid communication with at least one of a corresponding inlet of a heat pipe from the plurality of heat pipes and a corresponding inlet of a heat passage from the plurality of heat passages.   
     
     
         6 . The refrigerant circuit of  claim 1 , wherein the discharge conduit assembly comprises:
 a second diverter element adapted to connect at least one second header conduit with a plurality of second branch conduits for receiving the superheated refrigerant vapor, each of the plurality of second branch conduits adapted to be in fluid communication with at least one of a corresponding outlet of a heat pipe from the plurality of heat pipes and a corresponding outlet of a heat passage from the plurality of heat passages.   
     
     
         7 . The refrigerant circuit of  claim 1 , wherein the VFD unit is mounted on a first face of a base of the heat sink, the VFD unit comprising:
 a plurality of control modules, wherein one control module from the plurality of control modules is thermally coupled to at least one evaporator section of a corresponding heat passage from the plurality of heat passages and the at least one evaporator section of a corresponding heat pipe from the plurality of heat pipes.   
     
     
         8 . The refrigerant circuit of  claim 5 , wherein the first diverter element is adapted to receive the subcooled refrigerant fluid from the condenser. 
     
     
         9 . The refrigerant circuit of  claim 6 , wherein the second diverter element is adapted to supply the superheated refrigerant vapor to an accumulator. 
     
     
         10 . The refrigerant circuit of  claim 7 , wherein the subcooled refrigerant fluid in a first diverter element transitions to the superheated refrigerant vapor in a second diverter element upon absorbing heat from the VFD unit mounted on a portion of the base corresponding to at least one of the at least one evaporator section of the plurality of heat pipes and the at least one evaporator section of the plurality of heat passages. 
     
     
         11 . The refrigerant circuit of  claim 3 , wherein the at least one evaporator section and the at least one condenser section are disposed vertically along a longitudinal axis Y-Y′ of the base to form at least one of an I-shaped heat pipe and an I-shaped heat passage. 
     
     
         12 . The refrigerant circuit of  claim 3 , wherein the at least one evaporator section is disposed vertically along a longitudinal axis Y-Y′ of the base and the at least one condenser section is disposed horizontally along a lateral axis X-X′ of the base to collectively form at least one of an L-shaped heat pipe and an L-shaped heat passage. 
     
     
         13 . The refrigerant circuit of  claim 3 , wherein the at least one evaporator section and the at least one condenser section are disposed horizontally along a lateral axis X-X′ of the base and separated by a connecting section to collectively form at least one of a C-shaped heat pipe and a C-shaped heat passage. 
     
     
         14 . The refrigerant circuit of  claim 13 , wherein the connecting section comprises at least one sub section. 
     
     
         15 . A refrigerant circuit for cooling a Variable Frequency Drive (VFD) unit of an outdoor unit of an air conditioning system, the refrigerant circuit comprising:
 a condenser for condensing refrigerant vapor;   a heat sink for receiving a first portion of a subcooled refrigerant fluid from the condenser, the heat sink comprising:
 a supply conduit assembly and a discharge conduit assembly, wherein the supply conduit assembly is adapted to receive the first portion of the subcooled refrigerant fluid from the condenser and the discharge conduit assembly is adapted to discharge a superheated refrigerant vapor to an accumulator, wherein the first portion of the subcooled refrigerant fluid transitions to the superheated refrigerant vapor upon absorbing heat from the VFD unit thermally coupled to the heat sink; 
   the accumulator adapted to supply the superheated refrigerant vapor to a compressor;   an expansion valve for expanding a second portion of the subcooled refrigerant fluid;   an evaporator for evaporating the expanded second portion of the subcooled refrigerant fluid; and   a compressor, for compressing the evaporated refrigerant vapor from the evaporator and the superheated refrigerant vapor received from the accumulator.   
     
     
         16 . The refrigerant circuit of  claim 15 , wherein the outdoor unit comprises:
 a housing;   a heat sink according to  claims 3 or 4  mounted along a portion of the housing, the heat sink comprising:
 a first diverter element adapted to connect at least one first header conduit with a plurality of first branch conduits for supplying the subcooled refrigerant fluid, each of the plurality of first branch conduits adapted to be in fluid communication with at least one of a corresponding inlet of a heat pipe from the plurality of heat pipes and a corresponding inlet of a heat passage from the plurality of heat passages; and 
 a second diverter element adapted to connect at least one second header conduit with a plurality of second branch conduits for receiving the superheated refrigerant vapor, each of the plurality of second branch conduits adapted to be in fluid communication with at least one of a corresponding outlet of a heat pipe from the plurality of heat pipes and a corresponding outlet of a heat passage from the plurality of heat passages; and 
   the VFD unit mounted on the first face of the base of the heat sink, the VFD unit comprising:
 a plurality of control modules, wherein at least one control module from the plurality of control modules is thermally coupled to at least one of the at least one evaporator section of a corresponding heat pipe from the plurality of heat pipes and the at least one evaporator section of a corresponding heat passage from the plurality of heat passages. 
   
     
     
         17 . The refrigerant circuit of  claim 15 , wherein a first face of the base and corner portions of the housing adjacent to the first face of the base collectively define a secondary internal space enclosing the VFD unit. 
     
     
         18 . The refrigerant circuit of  claim 15 , wherein a second face and portions of the housing excluding the corner portions adjacent to the first face of the base define a primary internal space. 
     
     
         19 . The refrigerant circuit of  claim 15 , wherein a plurality of fins disposed on the second face and extending from a high temperature region of the base protrudes into the primary internal space housing an axial fan. 
     
     
         20 . The refrigerant circuit of  claim 15 , wherein the subcooled refrigerant fluid in the first diverter element transitions to the superheated refrigerant vapor in the second diverter element upon absorbing heat from the VFD unit mounted on at least one of the at least one evaporator section of a corresponding heat pipe from the plurality of heat pipes and the at least one evaporator section of a corresponding heat passage from the plurality of heat passages.