Refrigerant system with bypass line and dedicated economized flow compression chamber

Abstract

A refrigerant system has an economizer cycle. A vapor refrigerant from the economizer loop is returned to a dedicated economizer compression chamber. A main refrigerant is returned to a dedicated main compressor chamber. A bypass line communicates the two refrigerant flows.

1 . A refrigerant system comprising:
 at least two compression chambers, said at least two compression chambers for compressing a refrigerant, a downstream heat rejection heat exchanger, a refrigerant line passing from the heat rejection heat exchanger into an economizer cycle, and a main refrigerant line passing from the economizer cycle through a main expansion device and to a heat accepting heat exchanger, a suction line downstream of said heat accepting heat exchanger and extending to at least one of the at least two compression chambers;   a return line being returned from the economizer cycle to at least one other of the at least two compression chambers; and   a bypass line communicating the return line and the suction line.   
   
   
       2 . The refrigerant system as set forth in  claim 1 , wherein said bypass line includes a restriction to allow continuous communication between the return line and the suction line. 
   
   
       3 . The refrigerant system as set forth in  claim 2 , wherein said bypass line includes an electrically controlled valve to provide selective communication. 
   
   
       4 . The refrigerant system as set forth in  claim 3 , wherein said electrically controlled valve is a solenoid on/off valve. 
   
   
       5 . The refrigerant system as set forth in  claim 3 , wherein said electrically controlled valve is controlled by a pulse width modulation technique. 
   
   
       6 . The refrigerant system as set forth in  claim 3 , wherein said electrically controlled valve is a modulating valve. 
   
   
       7 . The refrigerant system as set forth in  claim 3 , wherein said electrically controlled valve is opened to equalize pressure upon refrigerant system shutdown or before startup. 
   
   
       8 . The refrigerant system as set forth in  claim 2 , wherein said restriction is an orifice. 
   
   
       9 . The refrigerant system as set forth in  claim 2 , wherein said restriction has a cross-section area between 0.1 square millimeter and 3 square millimeters. 
   
   
       10 . The refrigerant system as set forth in  claim 2 , wherein said restriction is a capillary tube. 
   
   
       11 . The refrigerant system as set forth in  claim 1 , further comprising an electrically controlled valve installed in parallel with said bypass line. 
   
   
       12 . The refrigerant system as set forth in  claim 1 , wherein said economizer cycle includes a flash tank to separate liquid and vapor refrigerant phases. 
   
   
       13 . The refrigerant system as set forth in  claim 1 , wherein said compression chambers are independent compressors. 
   
   
       14 . The refrigerant system as set forth in  claim 1 , wherein said compression chambers are positioned within a single compressor. 
   
   
       15 . The refrigerant system as set forth in  claim 14 , wherein said bypass line is located externally in relation to the compressor. 
   
   
       16 . The refrigerant system as set forth in  claim 14 , wherein said bypass line is located internally in relation to the compressor. 
   
   
       17 . The refrigerant system as set forth in  claim 14 , wherein said compressor is reciprocating compressor and said compression chambers are reciprocating compressor cylinders. 
   
   
       18 . The refrigerant system as set forth in  claim 1 , wherein at least one of said at least two compression chambers is represented by sequential compression stages. 
   
   
       19 . The refrigerant system as set forth in  claim 1 , wherein said economizer cycle includes an economizer heat exchanger having an economizer expansion device expanding a tapped portion of refrigerant and passing it through the economizer heat exchanger to exchange heat with the main refrigerant, with said tapped refrigerant being returned through the return line. 
   
   
       20 . The refrigerant system as set forth in  claim 1 , wherein at least one said compression chamber is a part of at least one reciprocating compressor cylinder. 
   
   
       21 . The refrigerant system as set forth in  claim 1 , wherein the refrigerant streams in said return line and suction line are partially combined together at subcritical pressure. 
   
   
       22 . The refrigerant system as set forth in  claim 1 , wherein said refrigerant is selected from a group consisting of R744, R22, R410A, R134a, R407C, R290, R600a refrigerants or their combinations. 
   
   
       23 . A method of operating a refrigerant system comprising:
 providing at least two compression chambers, said at least two compression chambers compressing refrigerant and delivering the refrigerant to a downstream heat rejection heat exchanger, refrigerant passing from the heat rejection heat exchanger into an economizer cycle, and a main flow of refrigerant passing from the economizer cycle through a main expansion device and to a heat accepting heat exchanger, refrigerant from the heat accepting heat exchanger passing through a suction line to at least one of the at least two compression chambers;   an economized flow of refrigerant, that is at least largely vapor, being returned from the economizer cycle to at least one other of the at least two compression chambers through a return line; and   communicating the return line and the suction line through a bypass line.   
   
   
       24 . The method as set forth in  claim 23 , wherein an electrically controlled valve on said bypass line is opened to unload the refrigerant system. 
   
   
       25 . The method as set forth in  claim 23 , wherein an electrically controlled valve on said bypass line is opened to return oil.