Flexible liquid desiccant heat and mass transfer panels with a hydrophilic layer

Abstract

Provided are flexible panel devices that use desiccants for heat and mass transfer processes, including but not limited to air conditioning systems, for example, liquid desiccant air conditioning (LDAC) applications wherein the liquid desiccant is contained in a panel that comprises at least one hydrophilic separation layer, which allows water vapor transfer between the air and liquid desiccant and enable dehumidification and humidification of the air. The flexible panel devices can be installed on an absorber (conditioner) side or a desorber (regenerator) side or both of a LDAC system. The devices have two flexible layers, at least one of which comprises a flexible and water vapor permeable hydrophilic separation layer, that form a desiccant flow channel and a desiccant flow distributor located therein. The two flexible layers may both be permeable hydropholic separation layers, or they may comprise one permeable hydrophilic separation layer along with another layer that may be a non-porous structure or a water-vapor permeable hydrophobic separation layer.

1 . A heat and mass transfer panel for water vapor exchange with a liquid desiccant, the panel comprising:
 a desiccant flow channel defined by a first flexible layer and a second flexible layer, at least one of which comprises a flexible hydrophilic water vapor-permeable separation layer;   a desiccant inlet and a desiccant outlet to the desiccant flow channel; and   a flexible desiccant flow distributor located in the desiccant flow channel.   
     
     
         2 . The heat and mass transfer panel of  claim 1 , wherein both the first and the second flexible layers comprise a flexible hydrophilic water-vapor permeable separation layer. 
     
     
         3 . The heat and mass transfer panel of  claim 1 , wherein the first flexible layer comprises a flexible hydrophilic water-vapor permeable separation layer and the second flexible layer is a non-porous layer or a hydrophobic water-vapor permeable separation layer. 
     
     
         4 . The heat and mass transfer panel of  claim 1 , wherein the flexible hydrophilic water-vapor permeable separation layer or layers independently comprise a membrane, a woven mesh, a nanofiber media, an electrospun fiber media, a glass fiber media, a nonwoven melt blown fiber media, a corrosion-resistant metal, a ceramic media, or combinations thereof. 
     
     
         5 . The heat and mass transfer panel of  claim 1 , wherein the flexible hydrophilic water-vapor permeable separation layer or layers independently comprise a micro-filtration or an ultra-filtration membrane comprising a hydrophilic nylon (PA) membrane, a hydrophilized polyethersulfone (PES) membrane, a hydrophilized polysulfone (PS) membrane, a hydrophilized polyvinylidene fluoride (PVDF) membrane, a hydrophilic polyacrylonitrile (PAN) membrane, a hydrophilized polypropylene (PP) membrane, a hydrophilized polyethylene (PE) membrane, a hydrophilized polytetrafluorethylene (PTFE) membrane, a hydrophilized polycarbonate (PC) membrane, a hydrophilized ethylene chlorotrifluoroethylene (ECTFE) membrane, or combinations thereof. 
     
     
         6 . The heat and mass transfer panel of  claim 1 , wherein the desiccant flow distributor comprises a hydrophilic material that comprises a polymeric material, a natural fiber, or combinations thereof. 
     
     
         7 . The heat and mass transfer panel of  claim 6 , wherein the desiccant flow distributor comprises a hydrophilic polymer material that comprises a membrane, an open cell foam, a porous nonwoven material, a porous woven material, or combinations thereof. 
     
     
         8 . The heat and mass transfer panel of  claim 1 , wherein the desiccant flow distributor comprises one or more draw-and-drip features at an outlet end of the distributor; wherein the draw-and-drip features are effective for facilitating uniform flow through the panel. 
     
     
         9 . The heat and mass transfer panel of  claim 1  further comprising an air channel layer. 
     
     
         10 . The heat and mass transfer panel of  claim 1  further comprising a desiccant distribution header. 
     
     
         11 . A heat and mass transfer module comprising:
 one or more panels of  claim 1  assembled among one or more air channel layers or air gaps; and   an air inlet and an air outlet.   
     
     
         12 . The heat and mass transfer module of  claim 11  further comprising two end plates between which the one or more panels and the one or more air channel layers are assembled. 
     
     
         13 . A method for water vapor exchange between air and a liquid desiccant, the method comprising:
 contacting the panel of  claim 1  with air having a water vapor pressure different from the equilibrium vapor pressure in a desiccant flowing through the desiccant flow channel;   wherein the humidity of the air after contact with the panel is different from the humidity before contact with the panel.   
     
     
         14 . A desiccant flow distributor comprising:
 a hydrophilic structure comprising a polymeric material, a natural fiber, or combinations thereof; and   one or more draw-and-drip features at an outlet end of the structure;   wherein the draw-and-drip features are effective for facilitating uniform flow therethrough.   
     
     
         15 . The desiccant flow distributor of  claim 14  comprising a hydrophilic polymeric material that comprises a membrane, an open cell foam, a porous nonwoven material, a porous woven material, or combinations thereof. 
     
     
         16 . The desiccant flow distributor of  claim 14 , wherein the one or more draw-and-drip features comprise a series of edges such that the linear edge near or at the outlet end of the structure is longer than the linear edge at the inlet end of the structure. 
     
     
         17 . The desiccant flow distributor of  claim 14 , wherein the one or more draw-and-drip features comprise a series of shapes defined by or at the edges of the outlet end.