Multiple-compressor system

Abstract

A climate-control system may include first and second compressors, a suction manifold, and a pressure-control flow path. The first compressor may include a first shell and a first compression mechanism. The first shell may include a first suction inlet through which working fluid is drawn into the first compressor for compression in the first compression mechanism. The second compressor may include a second shell and a second compression mechanism. The second shell may include a second suction inlet through which working fluid is drawn into the second compressor for compression in the second compression mechanism. The suction manifold has first and second arms coupled to the first and second suction inlets, respectively. The pressure-control flow path may be coupled to a discharge-pressure region and to a suction-pressure region of the second compressor.

What is claimed is: 
     
         1 . A climate-control system comprising:
 a first compressor including a first shell and a first compression mechanism, the first shell including a first suction inlet through which working fluid is drawn into the first compressor for compression in the first compression mechanism;   a second compressor including a second shell and a second compression mechanism, the second shell including a second suction inlet through which working fluid is drawn into the second compressor for compression in the second compression mechanism;   a suction manifold having a first arm and a second arm, wherein the first arm is coupled to the first suction inlet and is configured to provide working fluid to the first suction inlet, wherein the second arm is coupled to the second suction inlet and is configured to provide working fluid to the second suction inlet; and   a pressure-control flow path coupled to a discharge-pressure region of the climate-control system and to a suction-pressure region of the second compressor, wherein the pressure-control flow path includes a conduit and a valve that provide working fluid to the suction-pressure region of the second compressor at a pressure that is higher than pressure of working fluid in the first arm of the suction manifold.   
     
     
         2 . The climate-control system of  claim 1 , wherein the valve is movable between a first position in which fluid flow through the pressure-control flow path is prevented and a second position in which fluid flow through the pressure-control flow path is allowed. 
     
     
         3 . The climate-control system of  claim 2 , wherein the pressure-control flow path includes an expansion device. 
     
     
         4 . The climate-control system of  claim 2 , further comprising a control module in communication with the valve and controlling a position of the valve to control lubricant levels in the first and second shells. 
     
     
         5 . The climate-control system of  claim 4 , wherein the control module controls the position of the valve based on which of the first and second compressors are operating and which are in a shutdown state. 
     
     
         6 . The climate-control system of  claim 5 , wherein the control module controls the position of the valve based on capacity levels of the first and second compressors. 
     
     
         7 . The climate-control system of  claim 6 , wherein the control module controls the position of the valve based on data received from a high-side sensor and a low-side sensor. 
     
     
         8 . The climate-control system of  claim 7 , wherein the position of the valve is determined based on a predefined operating-envelope map. 
     
     
         9 . The climate-control system of  claim 1 , wherein:
 the first shell includes a first discharge outlet through which working fluid from the first compression mechanism is discharged from the first compressor,   the second shell includes a second discharge outlet through which working fluid from the second compression mechanism is discharged from the second compressor, and   the climate-control system includes a discharge conduit in fluid communication with the first and second discharge outlets and is configured to receive working fluid discharged from the first and second compressors.   
     
     
         10 . The climate-control system of  claim 9 , wherein:
 a first portion of the working fluid discharged from the second compression mechanism bypasses the discharge conduit and flows from the second compression mechanism to the pressure-control flow path, and   a second portion of the working fluid discharged from the second compression mechanism bypasses the pressure-control flow path and flows to the discharge conduit.   
     
     
         11 . The climate-control system of  claim 10 , wherein the pressure-control flow path extends from the second shell of the second compressor to the second arm of the suction manifold. 
     
     
         12 . The climate-control system of  claim 10 , wherein the pressure-control flow path extends from a first portion of the second shell defining a discharge chamber within the second shell to a second portion of the second shell defining a suction chamber of the second shell. 
     
     
         13 . The climate-control system of  claim 10 , wherein:
 the climate-control system includes a first discharge tube that fluidly connects the first discharge outlet with the discharge conduit,   the climate-control system includes a second discharge tube that fluidly connects the second discharge outlet with the discharge conduit, and   the pressure-control flow path extends from the second discharge tube to the second arm of the suction manifold.   
     
     
         14 . The climate-control system of  claim 9 , wherein:
 the climate-control system includes a first heat exchanger that receives working fluid from the discharge conduit,   the climate-control system includes an expansion device that receives working fluid from the first heat exchanger,   the climate-control system includes a second heat exchanger that receives working fluid from the expansion device,   the expansion device is disposed fluidly between the first and second heat exchangers,   a first portion of the working fluid discharged from the second compression mechanism bypasses the expansion device and the second heat exchanger and flows from the second compression mechanism to the pressure-control flow path and back to the second compression mechanism, and   a second portion of the working fluid discharged from the second compression mechanism bypasses the pressure-control flow path and flows to the first heat exchanger, the expansion device and the second heat exchanger.   
     
     
         15 . The climate-control system of  claim 14 , wherein the pressure-control flow path extends from the discharge conduit to a portion of the second shell that defines a suction chamber of the second shell. 
     
     
         16 . The climate-control system of  claim 14 , wherein the pressure-control flow path extends from a location between the first heat exchanger and the expansion device. 
     
     
         17 . The climate-control system of  claim 14 , wherein the pressure-control flow path extends to the second arm of the suction manifold. 
     
     
         18 . The climate-control system of  claim 14 , wherein the pressure-control flow path extends to a portion of the second shell that defines a suction chamber of the second shell. 
     
     
         19 . The climate-control system of  claim 14 , wherein the first portion of the working fluid discharged from the second compression mechanism bypasses the first heat exchanger. 
     
     
         20 . The climate-control system of  claim 14 , wherein:
 the climate-control system includes a third heat exchanger including a first conduit and a second conduit in a heat transfer relationship with the first conduit,   the first conduit fluidly connects the first heat exchanger and the expansion device,   the second conduit fluidly connects the first heat exchanger and the pressure-control flow path, and   the first and second conduits are fluidly isolated from each other.