Heat exchanger, method for operating the heat exchanger and use of the heat exchanger in an air-conditioning system

Abstract

In a heat exchanger having a bank of capillary tubes, in which a fluid to be cooled and/or heated is conducted through capillary tubes and in which the capillary tubes are wetted, in concurrent flow with the fluid, by water or by a hygroscopic sorption solution, and in which air flows around said capillary tubes in countercurrent flow in relation to the fluid, the bank of capillary tubes is composed of at least one tube mat, the capillary tubes of which have a hydrophilic or water-dispersing surface with a contact angle of less than 20°.

1 . A heat exchanger comprising:
 a capillary tube register, through which a fluid to be cooled and/or to be heated is led, the capillary tube register configured for being wetted with water or a hygroscopic sorption solution in parallel flow to the fluid and subjected to a flow of air in counterflow to the fluid,   wherein the capillary tube register comprises at least one capillary tube mat comprising capillary tubes, the capillary tubes comprising a hydrophilic or water-spreading surface with a contact angle below 20°.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein the capillary tubes are covered with a fleece. 
     
     
         3 . The heat exchanger according to  claim 2 , wherein the fleece comprises glass fibres having a diameter of 0.1 to 0.5 mm. 
     
     
         4 . The heat exchanger according to  claim 1 , wherein the capillary tubes are coated with a layer comprising water-spreading material. 
     
     
         5 . The heat exchanger according to  claim 4 , comprising a bonding agent layer between the capillary tubes and the layer comprising water-spreading material. 
     
     
         6 . The heat exchanger according to  claim 1 , wherein the capillary tube mat comprises capillary longitudinal and transverse tubes which are connected to each other in the manner of a network for the fluid passage, at least the capillary longitudinal tubes being connected in common by their ends respectively to one branch for the supply and discharge of the fluid. 
     
     
         7 . The heat exchanger according to  claim 6 , configured, for control of the flow course of the fluid in the capillary tube mat, wherein the passage for the fluid is blocked in individual capillary longitudinal and/or transverse tubes. 
     
     
         8 . The heat exchanger according to  claim 7 , wherein at least one branch of the capillary tube mat is shorter than a length of a side of the capillary tube mat parallel thereto. 
     
     
         9 . The heat exchanger according to  claim 7 , wherein the capillary tube mat comprises cut-outs in the interior or at the edge. 
     
     
         10 . The heat exchanger according to  claim 7 , wherein a flow course in the capillary tube mat is meandering. 
     
     
         11 . The heat exchanger according to  claim 10 , wherein a degree of meandering of the flow course inside the capillary tube mat changes. 
     
     
         12 . (Canceled) 
     
     
         13 . The heat exchanger according to  claim 6 , wherein the capillary longitudinal tubes and the capillary transverse tubes respectively extend diagonally relative to the branches. 
     
     
         14 . The heat exchanger according to  claim 6 , wherein the capillary longitudinal tubes and the capillary transverse tubes extend respectively at an angle of 45° relative to the branches for the supply and discharge of the fluid and are connected directly to these. 
     
     
         15 . The heat exchanger according to  claim 1 , wherein the capillary tube register comprises a plurality of capillary tube mats which are disposed parallel to each other, having a common supply line for the fluid on a side and a common discharge line for the fluid on an oppositely situated side. 
     
     
         16 . A method for operating a heat exchanger, the method comprising:
 altering a humidity of air using a capillary tube register, through which a fluid to be cooled and/or to be heated is led, the capillary tube register configured for being wetted with water or a hygroscopic sorption solution in parallel flow to the fluid and subjected to a flow of air in counterflow to the fluid, wherein the capillary tube register comprises at least one capillary tube mat comprising capillary tubes, the capillary tubes comprising a hydrophilic or water-spreading surface with a contact angle below 20°;   wherein the altering the humidity of air comprises dehumidifying air or humidifying air, wherein the dehumidifying comprises wetting the surface of the capillary tubes uniformly with a hygroroscopic sorption solution and discharging condensation heat of moisture withdrawn from the air using the fluid which is lead through the capillary tube register, and wherein the humidifying comprises wetting the surface of the capillary tubes uniformly with water and delivering evaporation heat for humidifying using the fluid which is lead through the capillary tube register.   
     
     
         17 . The method according to  claim 16 , wherein the altering the humidity comprises dehumidifying and wherein the sorption solution is an aqueous lithium chloride solution. 
     
     
         18 . The method according to  claim 16  wherein the altering the humidity comprises humidifying air, including wetting the surface of the capillary tubes uniformly with water and delivering the evaporation heat for humidifying the air using the fluid which is led through the capillary tube register. 
     
     
         19 . The method of  claim 16 , comprising using at least two of the heat exchangers in an air conditioner, including subjecting the heat exchangers to a flow of the fluid in a closed circulation in succession, the first heat exchanger being used for cooling and dehumidifying the ingoing air and the second heat exchanger for cooling the fluid by the outgoing air. 
     
     
         20 . The method according to  claim 19 , comprising cooling the outgoing air adiabatically to the dew point temperature thereof before flowing through the second heat exchanger. 
     
     
         21 . The method according to  claim 19 , comprising wetting the surface of the capillary tubes of the first heat exchanger with sorption solution and that of the second heat exchanger with water.