Cooling system and method for magnetic bearing compressors

Abstract

A cooling method and system, the system comprising a magnetic bearing centrifugal refrigeration compressor that uses liquid refrigerant from the condenser to supply cooling to its motor assembly; and a refrigerant pump installed in a motor cooling refrigerant supply line of the condenser; the refrigerant pump extending a low lift operating range of the compressor by allowing a controlled amount of liquid refrigerant to be pumped from the condenser.

1 . A cooling system, comprising:
 a condenser;   a magnetic bearing centrifugal refrigeration compressor that uses liquid refrigerant from the condenser to supply cooling to its motor assembly; and   a refrigerant pump installed in a motor cooling refrigerant supply line of said condenser;   wherein said refrigerant pump extends a low lift operating range of said compressor by allowing a controlled amount of liquid refrigerant to be pumped from said condenser.   
     
     
         2 . The cooling system of  claim 1 , wherein said condenser is one of: i) air cooled, ii) water cooled and iii) evaporatively cooled. 
     
     
         3 . The cooling system of  claim 1 , wherein said condenser is an an outdoor device. 
     
     
         4 . The cooling system of  claim 1 , wherein said refrigerant pump is one of: i) a magnetically coupled centrifugal pump and ii) a magnetic bearing centrifugal pump. 
     
     
         5 . The cooling system of  claim 1  wherein said refrigerant pump is fitted with a variable speed drive. 
     
     
         6 . The cooling system of  claim 1 , wherein said refrigerant pump is coupled with a refrigerant receiver tank. 
     
     
         7 . The cooling system of  claim 1 , wherein said refrigerant pump acts as a motor cooling liquid refrigerant pressure amplifier. 
     
     
         8 . The cooling system of  claim 1 , wherein said refrigerant pump is a fully sealed pump. 
     
     
         9 . The cooling system of  claim 1 , wherein said pump allows a controlled amount of liquid refrigerant to be pumped from said condenser to enable reliable starting of the system with cold ambient temperatures. 
     
     
         10 . A method for compression refrigeration, comprising:
 providing a magnetic bearing centrifugal refrigeration compressor that uses liquid refrigerant from a condenser to supply cooling to its motor assembly;   providing a cooling line including an evaporator connected to the compressor by a refrigerant pipe;   providing a refrigerant pump in a motor cooling refrigerant supply line of the condenser; and   varying the pump speed directly in relation to temperatures measured inside the compressor.   
     
     
         11 . A method for controlling a cooling system comprising a magnetic bearing centrifugal refrigeration compressor that uses a pressure sub cooled liquid refrigerant from a condenser to supply cooling to its motor assembly, comprising: providing a centrifugal refrigerant pump in the motor cooling refrigerant supply line of the condenser, increasing the condenser capacity and turning on the centrifugal refrigerant pump. 
     
     
         12 . A method for starting a cooling system comprising a magnetic bearing centrifugal refrigeration compressor that uses a pressure sub cooled liquid refrigerant from an outdoor air-cooled or evaporative condenser to supply cooling to its motor assembly, comprising: providing a centrifugal refrigerant pump in the motor cooling refrigerant supply line of the condenser and that allowing an amount of liquid refrigerant to be pumped from the outdoor air cooled condenser or evaporative condenser.