Membrane heat and mass exchanger and methods of manufacture

Abstract

A heat and mass exchange (HMX) device comprising a plurality of membranes arranged in a stack. Adjacent membranes are separated from one another by an airflow channel Each membrane of the stack comprises an array of integrated support structures that extend into the airflow channel and to the second membrane. The support structures comprise an adhesive material that is bonded to each membrane. The support structures divide the airflow channels into subchannels.

We claim: 
     
         1 . A heat and mass exchange (HMX) device, comprising:
 a plurality of membranes arranged in a stack, wherein:
 adjacent ones of the plurality of membranes are separated by an airflow channel; 
 the plurality of membranes comprise at least a first membrane and a second membrane over the first membrane; 
 the first membrane comprises an array of support structures integrated on the first membrane; and 
 the array of support structures each comprises an adhesive material that is bonded to the first membrane and extends to the second membrane. 
   
     
     
         2 . The heat and mass exchange device of  claim 1 , wherein the ones of the array of support structures are bonded to the second membrane by adhesive bonds. 
     
     
         3 . The heat and mass exchange device of  claim 1 , wherein:
 the ones of the plurality of membranes are elongated along a main axis and comprise a first header portion at a first end and a second header portion at a second end,   the first header portion and the second header portion each have two non-parallel sides extending to a vertex, wherein the membrane has an elongated hexagonal shape; and   the first header portion comprises a first array of fins oriented along a secondary axis that is non-parallel to the main axis, and the second header portion comprises a second array of fins oriented along the secondary axis.   
     
     
         4 . The heat and mass exchange device of  claim 1 , wherein the ones of the plurality of membranes comprise silica-filled polyethylene, silica-filled polyvinyl chloride, silica-filled PEEK, or perfluorosulfonic acid, and has a thickness ranging between 20 and 30 microns. 
     
     
         5 . The heat and mass exchange device of  claim 1 , wherein the adhesive material is any one of a silicone, an epoxy resin a urethane resin, a polyester resin, a silyl-terminated polyether resin, or an acrylic resin. 
     
     
         6 . The heat and mass exchange device of  claim 1 , wherein the array of support structures is an array of strip fins, wherein ones of the array of strip fins are substantially parallel to one another and have a longitudinal span that extends along a length of the membrane, a transverse span that extends in a direction that extends along a width of the membrane, and a z-height that is approximately equal to the z-height of the first or the second airflow channels. 
     
     
         7 . The heat and mass exchange device of  claim 6 , wherein the airflow channel is divided into two or more subchannels, wherein each one of the two or more subchannels is between a a pair of adjacent ones of the array of strip fins, wherein the pair of adjacent ones of the array of strip fins are sidewalls of each one of the two or more subchannels. 
     
     
         8 . The heat and mass exchange device of  claim 7 , wherein the two more subchannels have a hydraulic diameter between 2 mm and 3 mm. 
     
     
         9 . The heat and mass exchange device of  claim 6 , wherein ones of the array of strip fins have a ratio of the longitudinal span to the transverse span that is at least 100:1, and a ratio of the z-height to the transverse span that is between 1:1 and 2:1. 
     
     
         10 . The heat and mass exchange device of  claim 6 , wherein the ones of the array of strip fins have a z-height of 4 mm or less. 
     
     
         11 . The heat and mass exchange device of  claim 6 , wherein adjacent ones of the array of strip fins are separated from one another by a first distance that is one-tenth or less of the width of the membrane. 
     
     
         12 . The heat and mass exchange device of  claim 6 , wherein the ones of the array of strip fins comprise one or more curved portions. 
     
     
         13 . The heat and mass exchange device of  claim 1 , wherein the array of support structures is an array of pillars, wherein ones of the array of pillars each have a first transverse span extending along the membrane in the x- directions and a second transverse span extending along the membrane in the y-direction, and a z-height extending above the membrane, and wherein the z-height of the pillars is approximately the same as the z-height of the first or the second airflow channel. 
     
     
         14 . The heat and mass exchange device of  claim 13 , wherein the first and second transverse spans are substantially equal, and the ones of the array of pillars each have a ratio of z-height to width that ranges from 1:1 and 2:1, and a ratio of length-to-width that ranges from 1:1 to 20:1. 
     
     
         15 . The heat and mass exchange device of  claim 13 , wherein at least a portion of the ones of the array of pillars have a length extending along a first direction and a width extending along second direction that is orthogonal to the first direction, wherein the length is greater that the width. 
     
     
         16 . An energy recovery ventilation (ERV) system comprising:
 a housing;   a heat and mass exchange (HMX) device contained within the housing, the HMX device comprising:
 a plurality of membranes arranged in a stack, wherein:
 adjacent ones of the plurality of membranes are separated by an airflow channel; 
 the plurality of membranes comprise at least a first membrane and a second membrane over the first membrane; 
 the first membrane comprises an array of support structures integrated on the first membrane; and 
 the array of support structures each comprises an adhesive material that is bonded to the first membrane and extends to the second membrane; and 
 
   an air circulation system coupled to the HMX device such that air is circulated in a first direction through a first subarray of airflow channels, and in a second direction through a second subarray of airflow channels, wherein the first subarray is interleaved with the second subarray.   
     
     
         17 . The ERV system of  claim 16 , wherein
 the array of support structures is an array of strip fins, wherein the array of strip fins has a z-height that is approximately equal to the z-height of the first or the second airflow channels;   adjacent ones of the array of fins are sidewalls of a subchannel such that a first array of subchannels is within the first airflow channel and a second array of subchannels is within the second airflow channel; or   the array of support structures is an array of pillars, wherein the array of pillars has a z-height that is approximately equal to the z-height of the first or the second airflow channels   and   the first direction is opposite the second direction such that air is circulated through the HMX in a counterflow configuration, or the first direction is orthogonal to the second direction such that the air is circulated through the HMX in a cross-flow configuration.   
     
     
         18 . A method for making a heat and mass exchange device, comprising:
 receiving a heat and mass exchange (HMX) core stack, wherein the HMX core stack comprises a first membrane on the top of the core stack, the first membrane has a first surface over a second surface, the second surface bonded to a first layer of an adhesive material;   depositing a second layer of the adhesive material in a support structure array pattern on the first surface to form a plurality of support structures on the first surface; and   stacking a second membrane over the first membrane, wherein a third surface of the second membrane is opposite the first surface and is tacked onto the second layer of adhesive material, and the second membrane is at a first z-height over the first membrane.   
     
     
         19 . The method of  claim 18 , wherein depositing the adhesive material comprises:
 dispensing the second layer of the adhesive material from a nozzle over the first surface, wherein the nozzle is translated relative to the first surface to dispense the adhesive material in a pattern; or   dispensing the second layer of an adhesive material from the nozzle, wherein the wherein the nozzle is translated relative to the first surface in a first direction to deposit the adhesive material in a pattern; and   dispensing a third layer of the adhesive material from the nozzle over the second layer of the adhesive, wherein the nozzle is translated relative to the first surface in a second direction opposite the first direction.   
     
     
         20 . The method of  claim 18 , wherein stacking a second membrane over the first membrane comprises tacking the second membrane to the second layer of adhesive material and raising the second membrane to a second height over the first membrane and holding the position of the second membrane over the first membrane for a time period, wherein the adhesive material is stretched over the first membrane, and wherein a height of the second layer of adhesive material over the first membrane is increased and a height-to-width aspect ratio is 1:1 or greater.