A refrigeration system and method

Abstract

A refrigeration system includes a compressor for compressing a gaseous refrigerant, such that the temperature and pressure thereof increases, whereas the boiling point thereof decreases; a condenser, in which the gaseous refrigerant from the compressor exchanges heat with a high temperature heat carrier, said heat exchange resulting in the refrigerant condensing; an expansion valve reducing the pressure of liquid refrigerant from the condenser, hence reducing the boiling point of the refrigerant; an evaporator, in which the low boiling point refrigerant exchanges heat with a low temperature heat carrier, such that the refrigerant vaporizes; and a suction gas heat exchanger exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator. The low temperature gaseous refrigerant entering the suction gas heat exchanger contains a certain amount of low temperature liquid refrigerant, said low temperature liquid refrigerant vaporizing as a result of the heat exchange with the high temperature liquid refrigerant from the condenser. Disclosed is also a refrigeration method.

1 . A refrigeration system comprising:
 a compressor for compressing a gaseous refrigerant, such that the temperature and pressure thereof increases, wherein the boiling point thereof increases;   a condenser, in which the gaseous refrigerant from the compressor exchanges heat with a high temperature heat carrier, said heat exchange resulting in the refrigerant condensing;   an expansion valve reducing the pressure of liquid refrigerant from the condenser, hence reducing the boiling point of the refrigerant;   an evaporator, in which the low boiling point refrigerant exchanges heat with a low temperature heat carrier, such that the refrigerant vaporizes; and   a suction gas heat exchanger exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator,   wherein the low temperature gaseous refrigerant entering the suction gas heat exchanger contains a certain amount of 2-15 percent by mass of low temperature liquid refrigerant, said low temperature liquid refrigerant vaporizing as a result of the heat exchange with the high temperature liquid refrigerant from the condenser.   
     
     
         2 . The refrigeration system according to  claim 1 , wherein the certain amount of low temperature liquid refrigerant amounts to 5-10 percent by mass. 
     
     
         3 . The refrigeration system according to  claim 2 , wherein the certain amount of low temperature liquid refrigerant amounts to 6-9 percent by mass. 
     
     
         4 . The refrigeration system according to  claim 3 , wherein the certain amount of low temperature liquid refrigerant amounts to 7 percent by mass. 
     
     
         5 . The refrigeration system according to  claim 1 , wherein the evaporator is a plate heat exchanger comprising heat exchanger plates with at least first, second, third and fourth large port openings and a dividing surface dividing the heat exchanger plates into a first heat exchanging portion and a second heat exchanging portion, wherein the second heat exchanging portions are provided with first and second small port openings to form an integrated suction gas heat exchanger. 
     
     
         6 . The refrigeration system according to  claim 5 , wherein the dividing surface divides the heat exchanger plates into the first heat exchanging portion and the second heat exchanging portion, so that fluid passing between the first and second large port openings exchanges heat with fluids passing between the third and fourth port openings over the first heat exchanging portion of each plate and fluid passing between the first and second small port openings over the second heat exchanging portion of each plate. 
     
     
         7 . The refrigeration system according to  claim 5 , wherein the dividing surface is arranged between neighbouring sides of the heat exchanger plates. 
     
     
         8 . The refrigeration system according to  claim 5 , wherein the dividing surface comprises a flat surface provided at the same height as areas surrounding the first and second large port openings. 
     
     
         9 . The refrigeration system according to  claim 5 , wherein the dividing surface extends between the first large port opening and the remaining large port openings, and wherein the first and second small port openings are arranged on the same side of the dividing wall as the first large port opening. 
     
     
         10 . A refrigeration method comprising the steps of
 in a compressor, compressing a gaseous refrigerant, such that the temperature and pressure thereof increases, wherein the boiling point thereof increases;   feeding the gaseous refrigerant to a condenser, in which the gaseous refrigerant from the compressor exchanges heat with a high temperature heat carrier, said heat exchange resulting in the refrigerant condensing;   by an expansion valve, reducing the pressure of liquid refrigerant from the condenser, hence reducing the boiling point of the refrigerant;   feeding the low boiling point refrigerant to an evaporator, in which the low boiling point refrigerant exchanges heat with a low temperature heat carrier, such that the refrigerant partially vaporizes; and   in a suction gas heat exchanger integrated with the evaporator, exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator,   wherein the low temperature gaseous refrigerant entering the suction gas heat exchanger contains a certain amount of 2-15 percent by mass of low temperature liquid refrigerant, said low temperature liquid refrigerant vaporizing as a result of the heat exchange with the high temperature liquid refrigerant from the condenser.   
     
     
         11 . The refrigeration method according to  claim 10 , wherein the certain amount of low temperature liquid refrigerant amounts to 5-10 percent by mass. 
     
     
         12 . The refrigeration method according to  claim 11 , wherein the certain amount of low temperature liquid refrigerant amounts to 6-9 percent by mass. 
     
     
         13 . The refrigeration method according to  claim 12 , wherein the certain amount of low temperature liquid refrigerant amounts to 7 percent by mass. 
     
     
         14 . The refrigeration method according to  claim 10 , comprising the step of exchanging heat between the refrigerant and the low temperature heat carrier in the evaporator in a co-current flow. 
     
     
         15 . The refrigeration method according to  claim 10 , comprising the step of reversing the flow of refrigerant by a four-way valve.