Coated membranes for enthalpy exchange and other application

Abstract

Coated membranes comprise a porous desiccant-loaded polymer substrate that is coated on one surface with a thin layer of water permeable polymer. Such membranes are particularly suitable for use in enthalpy exchangers and other applications involving exchange of moisture and optionally heat between gas streams with little or no mixing of the gas streams through the membrane. Such membranes have favorable heat and humidity transfer properties, have suitable mechanical properties, are resistant to the crossover of gases when the membranes are either wet or dry, and are generally low cost.

1 - 26 . (canceled) 
     
     
         27 . A heat and humidity exchanger comprising a membrane cartridge, said membrane cartridge comprising a membrane, wherein said membrane is a water transport membrane comprising a porous substrate with a water permeable coating formed on one surface thereof, and wherein said substrate comprises a desiccant-loaded porous polymer film and said coating comprises a water permeable polymer. 
     
     
         28 . The heat and humidity exchanger of  claim 27  wherein said heat and humidity exchanger is an energy recovery ventilator, and said membrane cartridge is an energy recovery ventilator core. 
     
     
         29 . The heat and humidity exchanger of  claim 27  wherein said heat and humidity exchanger is a fuel cell humidifier. 
     
     
         30 . The heat and humidity exchanger of  claim 27  wherein said membrane cartridge is a pleated membrane cartridge. 
     
     
         31 . The heat and humidity exchanger of  claim 27  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         32 . The heat and humidity exchanger of  claim 28  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         33 . The heat and humidity exchanger of  claim 29  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         34 . The heat and humidity exchanger of  claim 30  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         35 . A method for transferring heat and humidity between a first gas stream and a second gas stream, said method comprising directing said first and second gas streams on opposite sides of a water transport membrane, said water transport membrane comprising a porous substrate with a water permeable coating formed on one surface thereof, wherein said porous substrate comprises a desiccant-loaded polymer film and said coating comprises a water permeable polymer. 
     
     
         36 . The method of  claim 35  wherein said first gas stream is an air intake stream of a building and said second gas stream is an air exhaust stream of a building, and directing said first and second gas streams on opposite sides of said water transport membrane comprises directing said first and second gas stream on opposite sides of an energy recovery ventilator core comprising said water vapour transport membrane. 
     
     
         37 . The method of  claim 36  wherein said intake air stream is directed so that it contacts the coated surface of said water transport membrane. 
     
     
         38 . The method of  claim 35  wherein said first gas stream is a fuel cell inlet stream and said second gas stream is a fuel cell exhaust stream, and said water transport membrane is a component of a fuel cell humidifier. 
     
     
         39 . The method of  claim 35  wherein said water vapor transport membrane is pleated. 
     
     
         40 . The method of  claim 35  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         41 . The method of  claim 36  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer 
     
     
         42 . The method of  claim 37  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         43 . The method of  claim 38  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer. 
     
     
         44 . The method of  claim 39  wherein said desiccant-loaded porous polymer film is a silica-loaded polyolefin film, and said water permeable polymer is a cross-linked, non-ionic polyurethane-polyether polymer.