Flexible Heat/Mass Exchanger

Abstract

A flexible heat/mass exchanger constructed of flexible layers defining a flow channel and exterior surfaces. The heat/mass exchanger utilizes a working liquid, such as water, that is present in the flow channel during use. The heat/mass exchanger uses one or more porous and/or permeable materials to allow mass exchange between the working liquid in the flow channel and the environment surrounding the heat/mass exchanger. In a cooling mode, evaporation of the working liquid occurs via the mass exchange. In a dehumidification mode, moisture in the surrounding environment is transported to the working liquid via the mass exchange. In some embodiments, the heat/mass exchanger is made of a number of flexible sheets of material. One or more flexible heat/mass exchangers may be used to form a semi-closed system, such as a personal cooling system with a circulating coolant loop, or an open system, such as a personal hydration system.

1 . A system for use with a working liquid, comprising:
 a heat/mass exchanger that includes:
 a thin flexible body having a first face and a second face spaced from said first face, said thin flexible body comprising a plurality of layers defining a flow field region containing at least one passageway and having boundary margins, said plurality of layers fluidly sealingly attached to one another at least at said boundary margins; 
 wherein at least one of said plurality of layers is permeable so as to allow mass transfer of a portion of the working liquid from said at least one passageway to said first face of said thin flexible laminate when said heat/mass exchanger is in use. 
   
   
   
       2 . A system according to  claim 1 , wherein said flow field region contains a plurality of interconnecting flow channels, said plurality of layers fluidly sealingly attached to one another at multiple regions throughout said flow field region so as to define said plurality of interconnecting flow channels. 
   
   
       3 . A system according to  claim 2 , wherein said thin flexible body comprises two polymeric outer sheets at least one polymeric intermediate sheet fluidly sealingly secured to said two outer polymeric sheets therebetween, said at least one polymeric intermediate sheet having a plurality of openings partially defining ones of said plurality of interconnecting channels. 
   
   
       4 . A system according to  claim 3 , wherein said thin flexible body comprises two polymeric intermediate sheets sealingly secured to one another and having like openings formed therein, said like openings of one of said two polymeric intermediate sheets partially overlapping said like openings of the other of said two polymeric intermediate sheets, said like openings forming said plurality of interconnecting flow channels. 
   
   
       5 . A system according to  claim 4 , wherein said two polymeric intermediate sheets include corresponding respective sets of elongate strips defining ones of said like openings, said two polymeric intermediate sheets oriented so that said elongate strips of said corresponding respective sets cross one another to form overlap regions, said elongate strips fastened to one another at said overlap regions. 
   
   
       6 . A system according to  claim 4 , wherein said like openings form two-dimensional arrays on corresponding respective ones of said two polymeric intermediate sheets. 
   
   
       7 . A system according to  claim 6 , wherein said like openings are circular. 
   
   
       8 . A system according to  claim 4 , further comprising an inlet manifold and an outlet manifold in fluid communication with opposing ends of said plurality of interconnecting flow channels, said inlet and outlet manifolds formed by said two polymeric intermediate sheets. 
   
   
       9 . A system according to  claim 1 , wherein said thin flexible body comprises two flexible sheets providing said first and second outer faces and defining said at least one passageway. 
   
   
       10 . A system according to  claim 9 , wherein said at least one passageway is defined by partially overlapping sets of depressions formed in corresponding respective ones of said two flexible sheets. 
   
   
       11 . A system according to  claim 1 , wherein the system is a personal hydration system comprising a human-wearable hydration pack, said mass/heat exchanger secured to said human-wearable hydration pack and in fluid communication therewith. 
   
   
       12 . A system according to  claim 1 , wherein the system is a personal cooling system comprising a liquid cooled garment, said mass/heat exchanger in fluid communication with said liquid cooled garment so as to provide a circulation path for the working fluid to and from said liquid cooled garment. 
   
   
       13 . A system according to  claim 12 , further comprising a makeup liquid reservoir in fluid communication with said heat/mass exchanger for making up a portion of the working liquid lost to the mass transfer. 
   
   
       14 . A system according to  claim 13 , further comprising a fan, said fan and said heat/mass exchanger located so that said fan moves air across at least one of said first and second surfaces during use so as to assist evaporation of a portion of the working liquid therefrom. 
   
   
       15 . A system according to  claim 1 , wherein said heat/mass exchanger comprises an inlet manifold, an outlet manifold and multiple ones of said thin flexible body, each of said multiple ones of said thin flexible body fluidly having a fluid inlet connected to said inlet manifold and a fluid outlet connected to said outlet manifold. 
   
   
       16 . A system according to  claim 1 , wherein said thin flexible body comprises a sheet folded into a plurality of pleats. 
   
   
       17 . A system according to  claim 1 , wherein said heat/mass exchanger has a central stacking axis and comprises multiple ones of said thin flexible body lying in corresponding respective planes perpendicular to said stacking axis, said multiple ones of said thin flexible body spaced from one another along said central stacking axis and defining a central open region surrounding said central stacking axis so that said central open region fluidly communicates with spaces between adjacent ones of said multiple ones of said thin flexible body. 
   
   
       18 . A system according to  claim 17 , wherein said multiple ones of said thin flexible body are configured so that, during operation, the working fluid flows through said multiple ones of said thin flexible body circumferentially relative to said central stacking axis. 
   
   
       19 . A system according to  claim 18 , further comprising a fan, said fan and said heat/mass exchanger configured so that air flows radially within said spaces between adjacent ones of said multiple ones of said thin flexible body. 
   
   
       20 . A system according to  claim 1 , wherein said at least one of said plurality of layers that is permeable is permeable by virtue of a porous material. 
   
   
       21 . A system according to  claim 1 , wherein said at least one of said plurality of layers that is permeable is permeable by virtue of a liquid impermeable, vapor permeable material. 
   
   
       22 . A system according to  claim 1 , wherein said at least one passageway is provided by a three-dimensional fibrous sheet. 
   
   
       23 . A heat/mass exchanger for use with a working fluid in an ambient environment, comprising:
 a flexible laminate having a flexible first sheet and a flexible second sheet fluidly sealed around a boundary region, each of said flexible first and second sheets having an external face exposed to the ambient environment during use;   a flow channel defined by said flexible first sheet, said flexible second sheet and said boundary region, said flow channel containing the working fluid during use; and   either or both said flexible first and second sheets configured to transport a portion of the working fluid from the flow channel to said external face of either or both of said flexible first and second sheets.   
   
   
       24 . A heat/mass exchanger according to  claim 23 , wherein said flow channel is provided by a flow matrix of interconnecting flow passageways defined by said flexible first sheet, said flexible second sheet and said boundary region. 
   
   
       25 . A heat/mass exchanger according to  claim 24 , wherein said flexible laminate comprises two flexible intermediate layers sealingly secured to one another and to said flexible first and second sheets and having like openings formed therein, said like openings of one of said two flexible intermediate layers partially overlapping said like openings of the other of said two flexible intermediate layers, said like openings forming said interconnecting flow passageways. 
   
   
       26 . A heat/mass exchanger according to  claim 25 , wherein said two flexible intermediate layers include corresponding respective sets of elongate strips defining ones of said like openings, said two flexible intermediate layers oriented so that said elongate strips of said corresponding respective sets cross one another to form overlap regions, said elongate strips fastened to one another at said overlap regions. 
   
   
       27 . A heat/mass exchanger according to  claim 26 , wherein said like openings form two-dimensional arrays on corresponding respective ones of said two flexible intermediate layers. 
   
   
       28 . A heat/mass exchanger according to  claim 27 , wherein said like openings are circular. 
   
   
       29 . A heat/mass exchanger according to  claim 26 , further comprising an inlet manifold and an outlet manifold in fluid communication with opposing ends of said interconnecting flow passageways, said inlet and outlet manifolds formed by said two flexible intermediate layers. 
   
   
       30 . A heat/mass exchanger according to  claim 24 , wherein said interconnecting flow passageways are defined by partially overlapping sets of depressions formed in corresponding respective ones of said flexible first and second sheets. 
   
   
       31 . A heat/mass exchanger according to  claim 23 , wherein said either or both said flexible first and second sheets is permeable by virtue of a porous material. 
   
   
       32 . A heat/mass exchanger according to  claim 23 , wherein said either or both said flexible first and second sheets is permeable by virtue of a liquid impermeable, vapor permeable material. 
   
   
       33 . A heat/mass exchanger according to  claim 23 , wherein said flow channel is provided by a three-dimensional fibrous sheet. 
   
   
       34 . A hydration system, comprising:
 a hydration reservoir for storing potable water during use; and   a heat/mass exchanger fluidly coupled with said hydration reservoir downstream thereof, said heat/mass exchanger including:
 a thin flexible body having a first face and a second face spaced from said first face, said thin flexible body comprising a plurality of layers defining a flow channel region containing a flow channel and having boundary margins, said plurality of layers fluidly sealingly attached to one another at said boundary margins so as to define said flow channel; 
 a water inlet fluidly coupled between said hydration reservoir and said flow channel for providing the potable water thereto; and 
 a water outlet fluidly coupled to said flow channel for conducting the potable water therefrom; 
 wherein at least one of said plurality of layers is permeable so as to allow mass transfer of a portion of the working liquid from said flow channel to said first face of said thin flexible laminate when said heat/mass exchanger is in use. 
   
   
   
       35 . A hydration system according to  claim 34 , wherein said hydration reservoir is contained in a human-portable hydration pack. 
   
   
       36 . A hydration system according to  claim 35 , wherein said human-portable hydration pack has an exterior and said heat/mass exchanger is secured to said human-portable hydration pack on said exterior. 
   
   
       37 . A hydration system according to  claim 34 , wherein said flow channel comprises a plurality of interconnecting flow passageways, said plurality of layers fluidly sealingly attached to one another at said boundary margins and attached to one another throughout said flow channel region so as to define said plurality of interconnecting flow passageways. 
   
   
       38 . A hydration system according to  claim 37 , wherein said thin flexible body comprises two polymeric outer sheets at least one polymeric intermediate sheet fluidly sealingly secured to said two outer polymeric sheets therebetween, said at least one polymeric intermediate sheet having a plurality of openings partially defining ones of said plurality of interconnecting flow passageways. 
   
   
       39 . A hydration system according to  claim 37 , wherein said thin flexible body comprises two polymeric intermediate sheets sealingly secured to one another and having like openings formed therein, said like openings of one of said two polymeric intermediate sheets partially overlapping said like openings of the other of said two polymeric intermediate sheets, said like openings forming said plurality of interconnecting flow passageways. 
   
   
       40 . A hydration system according to  claim 39 , wherein said two polymeric intermediate sheets include corresponding respective sets of elongate strips defining ones of said like openings, said two polymeric intermediate sheets oriented so that said elongate strips of said corresponding respective sets cross one another to form overlap regions, said elongate strips fastened to one another at said overlap regions. 
   
   
       41 . A hydration system according to  claim 39 , wherein said like openings form two-dimensional arrays on corresponding respective ones of said two polymeric intermediate sheets. 
   
   
       42 . A hydration system according to  claim 41 , wherein said like openings are circular. 
   
   
       43 . A hydration system according to  claim 39 , further comprising an inlet manifold and an outlet manifold in fluid communication with opposing ends of said interconnecting flow channels, said inlet and outlet manifolds formed by said two polymeric intermediate sheets. 
   
   
       44 . A hydration system according to  claim 37 , wherein said thin flexible body comprises two flexible sheets providing said first and second outer faces and defining said interconnecting flow passageways. 
   
   
       45 . A hydration system according to  claim 44 , wherein said interconnecting flow channels are defined by partially overlapping sets of depressions formed in corresponding respective ones of said two flexible sheets. 
   
   
       46 . A hydration system according to  claim 34 , wherein said at least one of said plurality of layers that is permeable is permeable by virtue of a porous material. 
   
   
       47 . A hydration system according to  claim 34 , wherein said at least one of said plurality of layers that is permeable is permeable by virtue of a liquid impermeable, vapor permeable material. 
   
   
       48 . A hydration system according to  claim 34 , wherein air is forced across the permeable face of the heat/mass exchanger by an air-moving device. 
   
   
       49 . A hydration system according to  claim 34 , wherein said flow channel is provided by a three-dimensional fibrous sheet.