Heat Exchange Element and Process for Production

Abstract

The invention provides a heat exchange element comprising a substrate and a coating, wherein the coating is present on at least a part of a flow path defined by the heat exchange element. The coating comprises a metal and has a structure comprising spikes having a length of up to 100 μm; the average length of the spikes various throughout the coating. The invention also provides a method of transferring heat to or from a fluid which comprises providing the fluid to a flow path of the heat exchange element of the invention. The invention further provides a process for producing a heat exchange element of the invention, wherein the process comprises providing an electroless deposition solution to a surface of a substrate. The invention further provides a flow process for producing a heat exchange element and a heat exchange element obtained or obtainable by that process.

1 . A heat exchange element comprising a substrate and a coating, wherein the heat exchange element defines a flow path for flow of fluid, and wherein at least a part of the flow path is coated with the coating, wherein:
 the coating comprises a metal;   the coating comprises a plurality of spikes having a length of up to 100 μm;   the coating comprises a first region at an end of the flow path in which the average spike length is S 1  and a second region on the flow path in which the average spike length is S 2 ; and   S 1  is greater than S 2 .   
     
     
         2 . A heat exchange element according to  claim 1  wherein the spikes have a length of at least 1 μm and no more than 50 μm. 
     
     
         3 . A heat exchange element according to  claim 1  or wherein S 2  is from 50% to 90% of S 1 . 
     
     
         4 . A heat exchange element according to  claim 1  wherein S 1  is from 2 μm to 10 μm. 
     
     
         5 . A heat exchange element according to  claim 1  wherein the spikes have a thickness at their tip of 100 nm or less. 
     
     
         6 . A heat exchange element according to  claim 1  wherein the said plurality of spikes are arranged in one or more clusters, wherein each cluster comprises two or more spikes. 
     
     
         7 . A heat exchange element according to  claim 6  wherein the diameter of each cluster is from 10 to 50 μm. 
     
     
         8 . A heat exchange element according to  claim 1  wherein the thickness of the coating is 10 μm or more. 
     
     
         9 . A heat exchange element according to  claim 1  wherein the coating comprises copper. 
     
     
         10 . A heat exchange element according to  claim 1  wherein the coating comprises 80% metal by weight of the coating. 
     
     
         11 . (canceled) 
     
     
         12 . A heat exchange element according to  claim 1  wherein the average spike length is graduated along all or part of the flow path. 
     
     
         13 . A heat exchange element according to  claim 1  wherein the coating comprises a surface layer on the coating. 
     
     
         14 . A heat exchange element according to  claim 1  wherein the substrate is a metal object. 
     
     
         15 . A heat exchange element according to  claim 1  wherein the substrate is a heat exchanger suitable for transferring heat to a liquid. 
     
     
         16 . A heat exchange element according to  claim 1  wherein the flow path comprises a flow channel and wherein the coating is present on at least a part of the surface of said flow channel. 
     
     
         17 . A heat exchange element according to  claim 16  wherein the first region is located at or near to an inlet to said flow channel and wherein the second region is located at a greater distance from the inlet than the first region. 
     
     
         18 . A heat exchange element according to  claim 1  wherein the heat exchange element contains a refrigerant. 
     
     
         19 . A method of transferring heat to or from a fluid which comprises providing the fluid to a flow path of a heat exchange element as defined in  claim 1 . 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . A process for producing a heat exchange element comprising a substrate and a coating, wherein:
 the coating comprises a metal; and   flowing an electroless deposition solution over a surface of the substrate.   
     
     
         24 . A process according to  claim 23  wherein the heat exchange element is as defined in of  claim 1 . 
     
     
         25 . A process according to  claim 23  wherein the process comprises:
 flowing the electroless deposition solution from a reservoir of electroless deposition solution over the surface of the substrate; and 
 returning the electroless deposition solution to the said reservoir. 
 
     
     
         26 . A process according to  claim 23  wherein the process comprises:
 flowing an electroless deposition solution over a surface of the substrate at a first flow rate F 1 ; and 
 flowing an electroless deposition solution over the said surface of the substrate at a second flow rate F 2  optionally wherein F 2  is greater than F 1 . 
 
     
     
         27 . (canceled) 
     
     
         28 . A process according to  claim 23  wherein the process comprises pumping the electroless deposition solution to cause the electroless deposition solution to flow over a surface of the substrate. 
     
     
         29 . A process according to  claim 23  wherein the substrate comprises a flow channel, and the process the process comprises flowing an electroless deposition solution through said flow channel. 
     
     
         30 . (canceled) 
     
     
         31 . A process according to  claim 23  wherein the electroless deposition solution is an aqueous solution. 
     
     
         32 . A process according to  claim 23  wherein the electroless deposition comprises copper and/or nickel ions. 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . A process according to  claim 23  wherein the process comprises providing the electroless deposition solution to a surface of the substrate for a time T, wherein T is the time taken for the electroless deposition solution to become depleted by 5 to 50%. 
     
     
         36 . (canceled) 
     
     
         37 . (canceled)