Heat exchanger for a co2 vehicle air conditioner

Abstract

A heat exchanger is described, having a first channel through which a stream of refrigerant flows on the high pressure side in a first direction, and a second channel, separate from the first channel, through which refrigerant flows on the low pressure side in a second direction opposite the first direction, wherein the first and second channels each have a large number of small channels ( 11, 12, 13 , . . . ) formed in or on individual heat transfer plates ( 1, 2, 3 , . . . ), and a plurality of layers of the heat transfer plates are soldered or welded together.

What is claimed is:  
     
         1 . A heat exchanger having a first channel through which a stream of refrigerant flows on the high pressure side and a second channel, separate from the first channel, through which refrigerant flows on the low pressure side, 
 wherein the first and second channels each have a large number of small channels ( 11 ,  12 ,  13 , . . . ) formed in or on individual heat transfer plates ( 1 ,  2 ,  3 , . . . ), and a plurality of layers of the heat transfer plates are joined together.    
     
     
         2 . The heat exchanger as recited in  claim 1 , 
 wherein the small channels conduct the flow in such a way that the refrigerant stream on the high pressure side and the refrigerant stream on the low pressure side flow through the heat exchanger according to the counterflow principle.    
     
     
         3 . The heat exchanger as recited in  claim 1  or  2 , 
 wherein the heat transfer plates are of a lamellar shape.  
 
     
     
         4 . The heat exchanger as recited in one of the preceding claims, 
 wherein the refrigerant on the high pressure and low pressure sides is CO 2 .    
     
     
         5 . The heat exchanger as recited in one of claims  1  through  4 , 
 wherein the hydraulic diameter of the small channels ( 11 ,  12 ,  13 , . . . ) is chosen such that the product of the heat transfer coefficient and the heat transferring area on the high pressure side corresponds to the product of the heat transfer coefficient and the heat transferring area on the low pressure side.  
 
     
     
         6 . The heat exchanger as recited in one of the preceding claims, 
 wherein the manner in which the small channels conduct the flow is chosen such that the product of the heat transfer coefficient and the heat transferring area on the high pressure side corresponds to the product of the heat transfer coefficient and the heat transferring area on the low pressure side.    
     
     
         7 . The heat exchanger as recited in  claim 6 , 
 wherein the small channels are routed in a zigzag pattern in or on the heat transfer plates.    
     
     
         8 . The heat exchanger as recited in one of the preceding claims, 
 wherein the material of the heat transfer plates ( 1 ,  2 ,  3 ) is chosen from a group which includes copper and copper alloy, stainless steel, aluminum, and additional materials.    
     
     
         9 . The heat exchanger as recited in one of the preceding claims, 
 wherein the small channels are produced in or on the heat transfer plates using a manufacturing process that removes or builds up material.    
     
     
         10 . The heat exchanger as recited in one of the preceding claims, wherein the lamellar heat transfer plates are enclosed between two opposing cover plates ( 8 ,  9 ), of which the first cover plate ( 8 ) has inlet and outlet orifices ( 14 ,  15 ,  16 ,  17 ) in each case for refrigerant on both the high pressure and low pressure sides.  
     
     
         11 . Use of the heat exchanger as recited in one of the preceding claims as an inner heat exchanger in a CO 2  air conditioner in vehicles, in particular in motor vehicles.  
     
     
         12 . The use as recited in  claim 11 , 
 wherein the inner heat exchanger is designed for high pressures of the CO 2  refrigerant up to approximately 150 bar.    
     
     
         13 . The use as recited in  claim 11  or  12 , 
 wherein CO 2  flows through the first channel of the inner heat exchanger in a first flow path from a gas cooler to an evaporator and through the second channel in a second flow path from the evaporator to a compressor of the vehicle air conditioner.  
 
     
     
         14 . The use as recited in one of claims  11  through  13 , 
 wherein in the first flow path a high pressure up to approximately 150 bar and a high temperature prevail, and in the second flow path a low pressure up to approximately 60 bar and a lower temperature prevail.  
 
     
     
         15 . The heat exchanger as recited in one of the preceding claims, 
 wherein the small channels ( 11 ) of the first heat transfer plate ( 1 ) are positioned at an offset from the small channels ( 12 ) of the second heat transfer plate ( 2 ).