Heat transfer circuit with increased bearing lubricant temperature, and method of supplying thereof

Abstract

A heat transfer circuit that includes a compressor with a gas bearing, a condenser, an expander, an evaporator, a lubricant stream, and a heat source. The lubricant stream receives a portion of the working fluid and supplies the portion of the working fluid to the gas bearing of the compressor. A method of supplying lubricant to a gas bearing of a compressor in a heat transfer circuit includes compressing and further heating at least a portion of the working fluid heated in the evaporator, and supplying the compressed and further heated working fluid to the gas bearing of the compressor. A method of the supplying lubricant to a gas bearing of a compressor in a heat circuit includes generating compressed gaseous working fluid within a lubricant stream.

What is claimed is: 
     
         1 . A heat transfer circuit, comprising:
 a compressor for compressing a working fluid, the compressor including a gas bearing;   a condenser for cooling the working fluid with a first process fluid;   an expander for expanding the working fluid;   an evaporator for heating the working fluid with a second process fluid;   a main flow path of the working fluid extending from the compressor through the condenser, the expander, the evaporator, and back to the compressor;   a lubricant stream including an inlet and an outlet, the inlet receiving a portion of the working fluid from the main flow path and the outlet supplying the portion of the working fluid to the gas bearing of the compressor, the portion of the working fluid includes one or more refrigerants that are each gaseous at the outlet of the lubricant stream; and   a heat source configured to increase one of a temperature of the working fluid flowing through the outlet of the lubricant stream and a temperature of the gas bearing.   
     
     
         2 . The heat transfer circuit of  claim 1 , wherein the portion of the working fluid supplied to the gas bearing from the lubricant stream has a superheat of at or about 4.0° F. or greater than 4.0° F. 
     
     
         3 . The heat transfer circuit of  claim 2 , wherein the lubricant stream includes the heat generating component, and the portion of the working fluid at the inlet of the lubricant stream has a superheat of less than 4.0° F. 
     
     
         4 . The heat transfer circuit of  claim 2 , wherein the superheat of the portion of the working fluid supplied to the gas bearing is at or about 5.0° F. or greater than 5.0° F. 
     
     
         5 . The heat transfer circuit of  claim 1 , wherein the inlet of the lubricant stream connects to the main flow path at the evaporator or after the evaporator and before the condenser. 
     
     
         6 . The heat transfer circuit of  claim 5 , wherein the inlet of the lubricant stream connects to the main flow path after the compressor and before the condenser. 
     
     
         7 . The heat transfer circuit of  claim 1 , wherein the heat source is a heater. 
     
     
         8 . The heat transfer circuit of  claim 7 , wherein the heater is an electric heater. 
     
     
         9 . The heat transfer circuit of  claim 7 , wherein the heater is a heat exchanger, the working fluid and a third process fluid flowing separately through the heater, the third process fluid heating the working fluid as the working fluid and the third process fluid flow through the heater. 
     
     
         10 . The heat transfer circuit of  claim 9 , further comprising:
 a cooling circuit including the heater and the third process fluid flowing through the cooling circuit.   
     
     
         11 . The heat transfer circuit of  claim 10 , wherein the cooling circuit includes one of a variable frequency drive and a motor of the compressor, the third process fluid cooling the one of the variable frequency drive and the motor of the compressor. 
     
     
         12 . The heat transfer circuit of  claim 7 , wherein the heater is attached to or is a part of the gas bearing. 
     
     
         13 . The heat transfer circuit of  claim 7 , wherein
 the lubricant stream includes a tank and a thermoelectric cooler, the heater and the thermoelectric cooler disposed within the tank,   the thermoelectric cooler and the thermoelectric cooler configured to generate compressed gaseous working fluid within the tank for the lubricant stream to supply to the gas bearing, the compressed gaseous working fluid generated by the thermoelectric cooler condensing the portion of the working fluid and the heater vaporizing the condensed working fluid.   
     
     
         14 . The heat transfer circuit of  claim 1 , wherein the one or more refrigerants include an HFO refrigerant. 
     
     
         15 . The heat transfer circuit of  claim 1 , wherein the compressor is an oil-free compressor. 
     
     
         16 . The heat transfer circuit of  claim 1 , wherein the lubricant stream includes an auxiliary compressor configured to compress the portion of the working fluid flowing through lubricant stream, the inlet of the lubricant stream connected to one of the evaporator, between the evaporator and the compressor, or a motor housing of the compressor. 
     
     
         17 . The heat transfer circuit of  claim 16 , wherein the auxiliary compressor is the heat source. 
     
     
         18 . A method of supplying lubricant to a gas bearing of a compressor in a heat transfer circuit, the heat transfer circuit including the compressor, a condenser, an expander, an evaporator, and a heater, a working fluid flowing through the heat transfer circuit, the method comprising:
 heating the working fluid in the evaporator with a process fluid;   compressing and further heating at least a portion of the working fluid heated in the evaporator, the further heating including the heater heating the portion of the working fluid heated in the evaporator, and the compressing including one of the compressor and an auxiliary compressor compressing the portion of the working fluid heated in the evaporator; and   supplying the compressed and further heated portion of the working fluid to the gas bearing of the compressor as the lubricant.   
     
     
         19 . The method of  claim 18 , wherein the compressed and further heated portion of the working fluid supplied to gas bearing has a superheat of at or about 4.0° F. or greater than 4.0° F. 
     
     
         20 . The method of  claim 18 , wherein the compressing includes the compressor compressing the working fluid heated in the evaporator, and the portion of the working fluid heated by the heater is a portion of the working fluid compressed by the compressor. 
     
     
         21 . A method of supplying lubricant to a gas bearing of a compressor in a heat transfer circuit, the heat transfer circuit including the compressor, a condenser, an expander, an evaporator, and a heat source, a working fluid flowing through the heat transfer circuit, a main flow path of the working fluid extending from the compressor through the condenser, the expander, the evaporator, and back to the compressor, the method comprising:
 suctioning a portion of the working fluid into the lubricant stream; and   generating compressed gaseous working fluid within the lubricant stream from the portion of the working fluid, the compressed gaseous working fluid supplied from the lubricant stream to the gas bearing of the compressor.   
     
     
         22 . The method of  claim 21 , wherein
 the portion of the working fluid is gaseous working fluid suctioned from the evaporator or a motor housing of the compressor, and   generating compressed gaseous working fluid within the lubricant stream from the portion of the working fluid includes an auxiliary compressor compressing the gaseous working fluid within the lubricant stream to generate the compressed gaseous working fluid.   
     
     
         23 . The method of  claim 21 , wherein
 suctioning the portion of the working fluid into the lubricant stream includes suctioning the portion of working fluid into a tank of the lubricant stream, and   generating compressed gaseous working fluid within the lubricant stream from the portion of the working fluid includes vaporizing the portion of the working fluid within the tank to generate the compressed gaseous working fluid   
     
     
         24 . The method of  claim 23 , wherein
 suctioning the portion of the working fluid into the lubricant stream includes one of:
 pumping the portion of the working fluid from the condenser into a tank of the lubricant stream, the portion of working fluid suctioned into the lubricant stream being liquid working fluid, and 
 condensing the portion of the working fluid within the tank of the lubricant stream, the portion of the working fluid suctioned into the lubricant stream being gaseous working fluid