Robust, high-thermal conductance, capillarity-enabled thin-film dry condensing surfaces

Abstract

Enhancing condensation heat transfer performance in applications including power generation, thermal management of high-performance electronics, water purification, distillation, natural gas processing, and air conditioning can be achieved with heat transfer devices. Condensation heat transfer can be enhanced via a hierarchical structure attached on a condenser surface. This novel hierarchical structure is composed of a thin, highly permeable, thermally conductive porous wick and a highly porous, robust, intrinsically hydrophobic membrane bonded or attached on top of the wick.

What is claimed is: 
     
         1 . A device providing condensation heat transfer comprising a hierarchical structure attached on a condenser surface. 
     
     
         2 . A capillary-driven condensation surface for a condenser surface comprising:
 a thermally conductive porous wick; and   a porous hydrophobic membrane on the wick.   
     
     
         3 . The surface of  claim 2 , wherein the thermally conductive porous wick is configured to be in thermal contact with the condenser surface. 
     
     
         4 . The surface of  claim 3 , wherein the thermally conductive porous wick includes a sintered metal powder, an electrodeposited porous metal, a metal foam, a metal mesh, a laser-etched metal, a 3D printed metal, a molded surface structure, or a patterned substrate. 
     
     
         5 . The surface of  claim 2 , wherein the thermally conductive porous wick is a copper foam, a copper mesh, a nickel foam, a stainless steel mesh, or an etched silicon structure. 
     
     
         6 . The surface of  claim 2 , wherein the thermally conductive porous wick has a porosity of at least 30%. 
     
     
         7 . The surface of  claim 2 , wherein the thermally conductive porous wick has a porosity of less than 98%. 
     
     
         8 . The surface of  claim 7 , wherein the thermally conductive porous wick has an average pore size of at least 1 micron. 
     
     
         9 . The surface of  claim 2 , wherein the porous hydrophobic membrane is bonded to or mechanically secured to a surface of the porous wick by physical attachment, such as clamps or ties, thermal attachment, such as by diffusion bonding, or localized melting or solidification, or stress-based attachment, such as by pre-forming the wick and membrane. 
     
     
         10 . The surface of  claim 2 , wherein the porous hydrophobic membrane has an average pore size of less than 10 microns. 
     
     
         11 . The surface of  claim 2 , wherein the porous hydrophobic membrane has an average pore size of greater than 10 nanometers. 
     
     
         12 . The surface of  claim 2 , wherein the porous hydrophobic membrane includes an organic polymer or an inorganic material. 
     
     
         13 . The surface of  claim 12 , wherein the porous hydrophobic membrane further includes a hydrophobic coating. 
     
     
         14 . The surface of  claim 12 , wherein the organic polymer is an electrospun fiber. 
     
     
         15 . The surface of  claim 14 , wherein the electrospun fiber has a diameter of between 0.05 microns and 4 microns. 
     
     
         16 . The surface of  claim 14 , wherein the electrospun fiber has a diameter of between 0.1 microns and 2 microns. 
     
     
         17 . The surface of  claim 2 , wherein the thermally conductive porous wick includes microchannels. 
     
     
         18 . The surface of  claim 2 , wherein the microchannels are arranged in rows or bands having a spacing of between 0.25 cm and 5 cm. 
     
     
         19 . The surface of  claim 2 , wherein the rows or bands are arranged substantially perpendicular to a lengthwise axis of the condenser surface. 
     
     
         20 . The surface of  claim 18 , further comprising drain ports adjacent to each of the rows or bands. 
     
     
         21 . A device having hierarchical structure for attachment to a condenser surface comprising:
 a thin, highly permeable, thermally conductive porous wick; and   a highly porous, robust, intrinsically hydrophobic membrane bonded or attached on top of the wick.   
     
     
         22 . A method of improving a heat transfer coefficient of a thermal system comprising:
 placing a capillary-driven condensation surface including a thermally conductive porous wick and a porous hydrophobic membrane on the wick on a surface of a condenser element of the thermal system.   
     
     
         23 . The method of  claim 22 , further comprising securing the capillary-driven condensation surface to the surface of the condenser element. 
     
     
         24 . A method of manufacturing a capillary-driven condensation surface for a condenser surface comprising:
 placing a porous hydrophobic membrane on a thermally conductive porous wick.   
     
     
         25 . The method of  claim 24 , further comprising cleaning a surface of the thermally conductive porous wick prior to placing the porous hydrophobic membrane. 
     
     
         26 . The method of  claim 24 , further comprising heat treating a surface of the thermally conductive porous wick prior to placing the porous hydrophobic membrane.