Compressor and hermetic housing with minimal housing ports

Abstract

A vapor compression system having a multi-stage compressor with a minimal number of ports located in the hermetically sealed compressor housing. A working fluid at suction pressure enters the compressor housing through a first port and is compressed to an intermediate pressure. The intermediate pressure refrigerant flows from the first stage compressor mechanism to the second stage compressor mechanism where it is compressed to a discharge pressure and discharged through a second port. The intermediate pressure refrigerant is in thermal communication with a heat exchange medium which is introduced into the compressor housing through a third port in the housing.

1 . A compressor assembly operable in a vapor compression system defining a fluid circuit for circulating a vapor, said compressor assembly comprising: 
 a hermetically sealed housing;    a first compressor mechanism disposed within said housing;    a second compressor mechanism disposed within said housing, wherein said first and second compressor mechanisms are operable to compress the vapor in two stages wherein said first compressor mechanism compresses the vapor from a suction pressure to an intermediate pressure and said second compressor mechanism compresses the vapor from the intermediate pressure to a discharge pressure; and    wherein said housing defines first, second and third ports, said first and second ports in fluid communication with said fluid circuit wherein suction pressure vapor is communicated from the fluid circuit to said compressor assembly through said first port and discharge pressure vapor is communicated from said compressor assembly to the fluid circuit through said second port, said third port defining a passage for a heat exchange medium, wherein thermal energy is transferable between the heat exchange medium and said compressor assembly, and wherein all superheated or wet vapors circulating within the circuit and all heat exchange mediums communicated through said housing are communicated through one of said first, second and third ports.    
   
   
       2 . The compressor assembly of  claim 1  wherein the heat exchange medium is a flash gas and said third port is in communication with an interior plenum defined by said housing, said first and second compressor mechanisms disposed within said interior plenum.  
   
   
       3 . The compressor assembly of  claim 1  wherein said interior plenum of said housing is at suction pressure.  
   
   
       4 . The compressor assembly of  claim 1  wherein said compressor assembly defines a flow path between said first compressor mechanism and said second compressor mechanism for intermediate pressure vapor and the heat exchange medium transfers thermal energy with the intermediate pressure vapor.  
   
   
       5 . The compressor assembly of  claim 4  wherein the heat exchange medium is a flash gas and said third port is in communication with an interior plenum defined by said housing, said first and second compressor mechanisms disposed within said interior plenum.  
   
   
       6 . The compressor assembly of  claim 1  further comprising a heat transfer device extending through said third port.  
   
   
       7 . The compressor assembly of  claim 6  wherein said heat transfer device is a heat pipe.  
   
   
       8 . The compressor assembly of  claim 1  wherein said third port is in communication with a sleeve, said housing defining an interior plenum, said sleeve extending within said plenum and defining an elongate volume in communication with said third port and sealingly separated from said plenum.  
   
   
       9 . The compressor assembly of  claim 8  further comprising a heat transfer device extending through said third port and partially disposed within said sleeve.  
   
   
       10 . A transcritical vapor compression system comprising: 
 a compressor assembly, a first heat exchanger, an expansion device and a second heat exchanger serially disposed in a fluid circuit circulating a refrigerant; said compressor assembly comprising:    a hermetically sealed housing;    a first compressor mechanism disposed within said housing;    a second compressor mechanism disposed within said housing, wherein said first and second compressor mechanisms are operable to compress the refrigerant in two stages wherein said first compressor mechanism compresses the refrigerant from a suction pressure to an intermediate pressure and said second compressor mechanism compresses the refrigerant from the intermediate pressure to a discharge pressure; and    wherein said housing defines first, second and third ports, said first and second ports in fluid communication with said fluid circuit wherein suction pressure refrigerant is communicated from the fluid circuit to said compressor assembly through said first port and discharge pressure refrigerant is communicated from said compressor assembly to the fluid circuit through said second port, said third port defining a passage for a heat exchange medium, wherein thermal energy is transferable between the heat exchange medium and said compressor assembly, and wherein all refrigerant circulating within said vapor compression system and all heat exchange mediums communicated through said housing are communicated through one of said first, second and third ports.    
   
   
       11 . The compressor assembly of  claim 10  wherein the heat exchange medium is a flash gas and said third port is in communication with an interior plenum defined by said housing, said first and second compressor mechanisms disposed within said interior plenum, the flash gas comprising relatively low pressure refrigerant diverted from said fluid circuit from a location between said expansion device and said compressor assembly.  
   
   
       12 . The compressor assembly of  claim 10  wherein said compressor assembly defines a flow path between said first compressor mechanism and said second compressor mechanism for intermediate pressure refrigerant and the heat exchange medium transfers thermal energy with the intermediate pressure refrigerant.  
   
   
       13 . The compressor assembly of  claim 12  wherein the heat exchange medium is a flash gas and said third port is in communication with an interior plenum defined by said housing, said first and second compressor mechanisms disposed within said interior plenum, the flash gas comprising relatively low pressure refrigerant diverted from said fluid circuit from a location between said expansion device and said compressor assembly.  
   
   
       14 . The compressor assembly of  claim 10  further comprising a heat transfer device extending through said third port.  
   
   
       15 . The compressor assembly of  claim 10  wherein the refrigerant comprises carbon dioxide.  
   
   
       16 . A method of compressing a refrigerant, said method comprising: 
 hermetically sealing a first compressor mechanism and a second compressor mechanism in a housing;    forming first, second and third ports in said housing;    introducing the refrigerant into said housing through said first port;    compressing the refrigerant in the first compressor mechanism from a suction pressure to an intermediate pressure;    compressing the refrigerant in the second compressor mechanism from the intermediate pressure to a discharge pressure;    discharging the refrigerant from the housing through said second port;    communicating a thermal exchange medium through said third port;    exchanging thermal energy between the intermediate pressure refrigerant and the thermal exchange medium; and    wherein all refrigerant and thermal exchange medium communicating through said housing is communicated through one of said first, second and third ports.    
   
   
       17 . The method of  claim 16  wherein said step of communicating a heat exchange medium through said third port comprises introducing a flash gas into said housing through said third port.  
   
   
       18 . The method of  claim 17  wherein said refrigerant comprises carbon dioxide and the discharge pressure exceeds the critical pressure of the refrigerant.  
   
   
       19 . The method of  claim 16  wherein communicating a heat exchange medium through said third port comprises extending a heat pipe through said third pipe.