Heat exchanger for a motor vehicle air conditioning system

Abstract

In an air/refrigerant heat exchanger, particularly for a motor vehicle air conditioning system, including a plurality of flat tubes arranged in closely spaced relationship so that a narrow flow passage for air is formed therebetween, the flat tubes include passages through which refrigerant is conducted in the longitudinal direction of the flat tubes and are provided on their outer surfaces with longitudinal parallel recesses and projections such that the flat tubes are wave-shaped the recesses and projections flattening out toward the narrow ends of the flat tubes and provide for narrow flat rectangular end sections.

1 . An air/refrigerant heat exchanger, particularly for a motor vehicle air conditioning system, comprising a plurality of flat tubes ( 2 ) having opposite walls ( 4 ,  5 ,  6 ,  7 ) arranged in closely spaced relationship so as to form between the walls of adjacent flat tubes narrow flow passages ( 8 ,  9 ) for the conduction of air therethrough, said flat tubes ( 2 ) including each a plurality of passages ( 3 ) and being provided at opposite ends with distribution connectors ( 10 ,  18 ) for conducting refrigerant through the passages ( 3 ) extending through the tubes ( 2 ), said distribution connectors ( 10 ,  18 ) having each at least one line connecter ( 33 ,  51 ,  52 ) for the connection of the flat tubes ( 2 ) in a refrigerant circuit of the air conditioning system, the refrigerant flow direction through the flat tubes ( 2 ) being essentially parallel to the main axis of the respective flat tubes ( 2 ), opposite walls ( 4 ,  5 ,  6 ,  7 ) of adjacent flat tubes ( 2 ) including longitudinal recesses ( 11 ,  80 ) and projections ( 81 ) such that the flat tubes ( 2 ) are wave-shaped, the recesses and projections flattening out toward both narrow opposite ends of the flat tubes ( 2 ) and, at the opposite ends, forming narrow flat rectangular end sections.  
   
   
       2 . An air/refrigerant heat exchanger according to  claim 1 , wherein longitudinal axes of the recesses ( 11 ,  80 ) and the projections ( 81 ) extend in the longitudinal direction of the flat tube ( 2 ) and transverse to the flow direction to an air flow over the outer surfaces of the flat tubes ( 2 ) such that the air flow over the tube surfaces is wave-shaped.  
   
   
       3 . An air/refrigerant heat exchanger according to  claim 1 , wherein the flat tubes ( 2 ) are provided with V-shaped recesses ( 11 ,  80 ) and projections ( 81 ) which extend at an oblique angle to the flow direction of the air flow and to the flow direction of the refrigerant through the flat tubes ( 2 ) that is, the longitudinal direction of the tubes ( 2 ).  
   
   
       4 . An air/refrigerant heat exchanger according to  claim 1 , wherein the recesses ( 11 ) extend through the flat tube ( 2 ) so that, at the opposite side of the tube ( 2 ) a corresponding projection is formed and the flat tube ( 2 ) is profiled at both sides thereof.  
   
   
       5 . An air/refrigerant heat exchanger according to  claim 1 , wherein the flat tube ( 2 ) has an end area ( 35 ,  37 ) with a cross-section which, in the direction of the axis of the flat tube ( 2 ), is rectangular and constant and a center section with a cross-section which continuously changes over the length of the flat tube ( 2 ).  
   
   
       6 . An air/refrigerant heat exchanger according to  claim 1 , wherein the facing surfaces ( 4 ,  5 ,  6 ,  7 ) of two adjacent flat tubes ( 2 ) are so arranged that at least one depression of a flat tube ( 2 ) received a projection of the adjacent flat tube so that a wave-shaped air flow channel is formed between the adjacent flat tubes ( 2 ).  
   
   
       7 . An air/refrigerant heat exchanger according to  claim 1 , wherein at least two flat tubes ( 2 ) are bundled and the end areas ( 35 ) of at least one of the bundled flat tubes ( 2 ) is offset relative to the flat tube surface thereof and disposed in close contact with the end area ( 31 ) of the adjacent flat tubes ( 2 ).  
   
   
       8 . An air/refrigerant heat exchanger according to  claim 1 , wherein the front ends of several flat tubes ( 2 ) are joined by a common comb-like spacer ( 70 ) which has projections ( 71 ) extending into the spaces between adjacent flat tubes ( 2 ).  
   
   
       9 . An air/refrigerant heat exchanger according to  claim 1 , wherein opposite surfaces ( 4 ,  5 ,  6 ,  7 ) of adjacent flat tubes ( 2 ) are provided with hydrophilic coatings which reduce the surface tension of water.  
   
   
       10 . An air/refrigerant heat exchanger according to  claim 1 , wherein the ratio of the inner refrigerant side surface area and the outer air side surface area of the flat tubes ( 2 ) is 0.7 to 1.5, preferably about 1.  
   
   
       11 . An air/refrigerant heat exchanger according to  claim 10 , wherein the ratio of the inner refrigerant side surface area and the outer air side surface area of the flat tubes ( 2 ) is about 1.  
   
   
       12 . An air/refrigerant heat exchanger according to  claim 1 , wherein the connection distributor ( 10 ,  18 ) is provided with pipe connections ( 51 ,  52 ) and includes a bottom plate ( 54 ′) which has at least two longitudinal channels ( 101  to  104 ) which divide the refrigerant flow into at least two refrigerant flows such that the refrigerant flow can be supplied, at least partially, to different flat tubes ( 2 ) or different numbers of flat tubes.  
   
   
       13 . An air/refrigerant heat exchanger comprising a plurality of flat tubes ( 2 ) arranged in parallel spaced relationship and including passages through which a refrigerant is conducted, parallel spaced walls ( 4 ,  5 ,  6 ,  7 ) of adjacent flat tubes ( 2 ) forming air flow channels ( 3 ), a plurality of spaced flat tubes ( 2 ) being joined at their ends to a connection distributor ( 10 ,  18 ) including at least one pipe connector ( 33 ,  51 ,  52 ) for connection to a tube system, said spaced walls ( 4 ,  5 ,  6 ,  7 ) of adjacent flat tubes ( 2 ) having longitudinal recesses ( 11 ,  80 ) and, respectively, projections ( 81 ) provided in such a way that they extend obliquely to the flow direction of the refrigerant flow through the flat tubes, the refrigerant flow extending essentially parallel to a main axis of the respective flat tube ( 2 ).  
   
   
       14 . An air/refrigerant heat exchanger according to  claim 13 , wherein the narrow front ends of several flat tubes ( 2 ) are joined by a common comb-like spacer ( 70 ) which has projections extending into the spaces between adjacent flat tubes ( 2 ).  
   
   
       15 . An air/refrigerant heat exchanger according to  claim 13 , wherein opposite surfaces ( 4 ,  5 ,  6 ,  7 ) of adjacent flat tubes ( 2 ) are provided with hydrophilic coatings which reduce the surface tension of water.  
   
   
       17 . An air/refrigerant heat exchanger according to  claim 13 , wherein the ratio of the inner refrigerant side surface area and the outer air side surface area of the flat tubes ( 2 ) is 0.7 to 1.5.  
   
   
       18 . An air/refrigerant heat exchanger according to  claim 17 , wherein the ratio of the inner refrigerant side surface area and the outer air side surface area of the flat tubes ( 2 ) is about 1.  
   
   
       19 . An air/refrigerant heat exchanger according to  claim 13 , wherein the connection distributor ( 10 ,  18 ) is provided with pipe connections ( 51 ,  52 ) and includes a bottom plate ( 54 ′) which includes at least two longitudinal channels ( 101  to  104 ) which divide the refrigerant flow into at least two refrigerant flows such that the refrigerant flow can be supplied, at least partially, to different flat tubes ( 2 ) or different numbers of flat tubes.  
   
   
       20 . An air/refrigerant heat exchanger, particularly for a motor vehicle air conditioning system, comprising a plurality of flat tubes ( 2 ) having opposite walls ( 4 ,  5 ,  6 ,  7 ) arranged in closely spaced relationship so as to form between the walls of adjacent flat tubes narrow flow passages ( 8 ,  9 ) for the conduction of air therethrough, said flat tubes ( 2 ) including each a plurality of passages ( 3 ) and being provided at opposite ends with distribution connectors ( 10 ,  18 ) for conducting refrigerant through the passages ( 3 ) extending through the flat tubes ( 2 ), said distribution connectors ( 10 ,  18 ) having each at least one line connecter ( 33 ,  51 ,  52 ) for the connection of the flat tubes ( 2 ) in a refrigerant circuit of the air conditioning system, the refrigerant flow direction through the flat tubes ( 2 ) being essentially parallel to the main axis of the respective flat tubes ( 2 ), the flat tubes ( 2 ) having end areas ( 35 ,  37 ) with a cross-section which, in the direction of the axes of the flat tubes ( 2 ) are rectangular and constant and center sections with a cross-section which continuously changes over the length of the flat tube ( 2 ).