Sorption cooling systems, their use in personal cooling applications and methods relating to the same

Abstract

A personal cooling device using a sorption cooling system to provide cooled fluid to a garment and methods relating to the same are provided. The sorption cooling system generally includes a lightweight, compact evaporator and adsorbent bed for providing the cooled fluid to the garment.

1 . A method of cooling a person using a personal cooling system, the method comprising: 
 (a) flowing dry air from an adsorber to an evaporator, said evaporator comprising: 
 i. a plurality of vapor-permeable membrane material layers, each of said plurality of vapor-permeable membrane materials having a first side and a second side;  
 ii. air-flow channels disposed adjacent to each of said first sides; and  
 iii. refrigerant flow channels disposed adjacent to each of said second sides, each of said refrigerant flow channels comprising liquid water;  
   (b) evaporating a first portion of said liquid water into said dry air thereby cooling a second portion of said liquid water; and    (c) flowing said cooled second portion of said liquid water through a garment worn by said person.    
   
   
       2 . The method of  claim 1 , wherein wet air is created from said step of evaporating a first portion of said liquid water into said dry air, the method further comprising the steps of: 
 (d) returning said wet air to said adsorber; and    (e) adsorbing water contained in said wet air.    
   
   
       3 . The method of  claim 2 , wherein said dry air is created from said adsorbing said water step.  
   
   
       4 . The method of  claim 1 , further comprising the step of: 
 (d) returning said second portion of water to said evaporator.    
   
   
       5 . The method of  claim 1 , wherein said flowing dry air step comprising flowing said dry air into said evaporator at a flow rate of between 0.33 liters per second and 0.83 liters per second.  
   
   
       6 . The method of  claim 1 , wherein said flowing said cooled second portion of said liquid water step comprises flowing said cooled second portion of said liquid water at a flow rate of about 10 liters per second.  
   
   
       7 . The method of  claim 1 , wherein said evaporator has a volumetric cooling density of at least about 80 W/liter.  
   
   
       8 . The method of  claim 1 , wherein said evaporator has a mass cooling density of at least about 100 W/kg.  
   
   
       9 . The method of  claim 1 , wherein said membrane material is selected from the group consisting of dense polyurethanes, expanded PTFE and combinations thereof.  
   
   
       10 . The method of  claim 1 , wherein said membrane material is substantially vapor permeable and liquid impermeable at between about 1.5 psi and 15 psi of liquid pressure.  
   
   
       11 . A personal cooling system comprising: 
 (a) a garment adapted to be worn by a person, said garment comprising at least one cooling channel;    (b) an evaporator comprising: 
 i. a first refrigerant flow channel containing a refrigerant, said first refrigerant flow channel adapted to fluidly communicate with said at least one cooling channel;  
 ii. a first air flow channel;  
 iii. a membrane material liquidly separating said first refrigerant flow channel from said first air flow channel;  
   (c) a circulating means for circulating said refrigerant through said cooling channels of said garment and said first refrigerant channel; and    (d) an air flow means for flowing air through said first air flow channel.    
   
   
       12 . The personal cooling system of  claim 11 , further comprising: 
 (e) an adsorber adapted for gaseous communication with said air flow channel of said evaporator, said adsorber being further adapted to adsorb vaporous refrigerant contained in an air stream.    
   
   
       13 . The personal cooling system of  claim 12 , wherein said adsorber comprises a plurality of desiccant sheets, each of said desiccant sheets comprising at least one aperture, said at least one aperture being a portion of an air flow path in gaseous communication with said air flow channel of said evaporator.  
   
   
       14 . The personal cooling system of  claim 11 , further comprising a refrigerant source for supplying a supplemental portion of refrigerant to said evaporator.  
   
   
       15 . The personal cooling system of  claim 11 , wherein said membrane material is from the group consisting of dense substituted polyurethanes, expanded PTFE and combinations thereof.  
   
   
       16 . The personal cooling system of  claim 11 , wherein said refrigerant flow channel and said cooling channel operate in a closed-loop.