Defrost refrigeration system

Abstract

A defrost refrigeration system of the type having a main refrigeration circuit comprising a first line extending from the compression stage to the evaporator stage and adapted to receive a portion of refrigerant in a high-pressure gas state. A valve system stops a flow of the refrigerant in a low-pressure liquid state to an evaporator of the evaporator stage and for conveying a flow of the refrigerant in the high-pressure gas state from the first line to release heat to defrost the at least one evaporator. A second line conveys the refrigerant having released heat directly to the condensing stage.

1 . A defrost refrigeration system of the type having a main refrigeration circuit, wherein a refrigerant goes through at least a compression stage, wherein said refrigerant is compressed to a high-pressure gas state to then reach a condensing stage, wherein said refrigerant in said high-pressure gas state is condensed at least partially to a high-pressure liquid state to then reach an expansion stage, wherein said refrigerant in said high-pressure liquid state is expanded to a first low-pressure liquid state to then reach an evaporator stage, wherein said refrigerant in said first low-pressure liquid state is evaporated at least partially to a first low-pressure gas state by absorbing heat, to then return to said compression stage, said defrost refrigeration system comprising: 
 a first line extending from the compression stage to the evaporator stage and adapted to receive a portion of said refrigerant in said high-pressure gas state;    a valve system for stopping a flow of said refrigerant in said first low-pressure liquid state to at least one evaporator of the evaporator stage and for conveying a flow of said refrigerant in said high-pressure gas state from the first line to release heat to defrost the at least one evaporator; and    a second line to convey said refrigerant having released heat directly to the condensing stage.    
   
   
       2 . The defrost refrigeration system according to  claim 1 , wherein the compression stage has at least one dedicated compressor connected to the first line so as to direct said portion of said refrigerant in said high-pressure gas state to the at least one evaporator being defrosted.  
   
   
       3 . The defrost refrigeration system according to  claim 2 , further comprising a selectively openable bypass line connecting the dedicated compressor to the condensing stage so as to direct the refrigerant compressed by the dedicated compressor directly to the condensing stage, thereby bypassing the defrosting of the at least one evaporator.  
   
   
       4 . The defrost refrigeration system according to  claim 2 , comprising a pressure reducing valve in a hot gas line between the compression stage and the condensing stage, the first line diverging from the hot gas line upstream of the pressure reducing valve, and the second line converging to the hot gas line downstream of the pressure reducing valve, whereby the pressure reducing valve induces a flow of said portion of said refrigerant through the first line and the second line to defrost the at least one evaporator.  
   
   
       5 . A method for defrosting evaporators in a refrigeration system operating a refrigeration cycle, comprising the steps of: 
 providing a first line extending from a compression stage of the refrigeration system to an evaporation stage of the refrigeration system, a second line extending from the evaporation stage of the refrigeration system directly to a condensing stage of the refrigeration system;    stopping a flow of cooling refrigerant to at least one evaporator;    conveying hot gas refrigerant from the compressing stage to the at least one evaporator through said first line so as to defrost the at least one evaporator; and    conveying the hot gas refrigerant from the at evaporator directly to the condensing stage by the second line so as to return the refrigerant to the refrigeration cycle.