Portable Cooling Unit

Abstract

A portable cooling unit operates by pumping liquid. Because the portable cooling unit pumps liquid, the compression system that generates the cooling power does not require the use of a condenser. The compression system utilizes a compression wave. An evaporator of the cooling unit operates in the critical flow regime in which the pressure in an evaporator tube will remain almost constant and then ‘jump’ or ‘shock up’ to an increased pressure.

1 . A portable cooling unit comprising:
 a pump that maintains a circulatory fluid flow through a flow path;   an evaporator that operates in the critical flow regime of a circulatory fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow with no heat being added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator;   a heat exchanging mechanism thermally coupled to the circulatory fluid flow; and   a storage compartment, the storage compartment receiving items to be cooled or maintained at a temperature below ambient, wherein the cooling unit is readily transportable.   
     
     
         2 . The portable cooling unit of  claim 1 , wherein the storage compartment forms a housing for the pump and the evaporator. 
     
     
         3 . The portable cooling unit of  claim 2 , wherein at least a portion of an external surface of the storage compartment serves as the heat exchanging mechanism by effectuating convection from the interior of the unit to the atmosphere. 
     
     
         4 . The portable cooling unit of  claim 1 , wherein the heat exchanging mechanism is a radiator. 
     
     
         5 . The portable cooling unit of  claim 1 , wherein a single tube is utilized in the evaporator. 
     
     
         6 . The portable cooling unit of  claim 5 , wherein the cooling unit generates approximately 80 watts of cooling power. 
     
     
         7 . The portable cooling unit of  claim 1 , wherein the unit is battery powered. 
     
     
         8 . The portable cooling unit of  claim 7 , wherein the battery is charged by a solar cell. 
     
     
         9 . The portable cooling unit of  claim 1 , wherein the unit is powered by a solar cell. 
     
     
         10 . The portable cooling unit of  claim 1 , wherein the pump raises the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSI. 
     
     
         11 . The portable cooling unit of  claim 1 , wherein the pump raises the pressure of the circulatory fluid flow to more than 100 PSI. 
     
     
         12 . A portable cooling system comprising:
 a storage compartment, the storage compartment receiving items to be cooled or maintained at a temperature below ambient;   a pump that maintains a fluid flow of a compressible fluid through the system; and   an evaporator that effects a phase change in the compressible fluid, wherein the system establishes a compression wave in the compressible fluid by passing the compressible fluid from a high pressure region to a low pressure region, the velocity of the fluid being greater than or equal to the speed of sound in the compressible fluid, the compressible fluid being cooled during a phase change so that heat is transferred from the system by thermally coupling one or more fins between the compressible fluid and the ambient atmosphere, and wherein the cooling unit is readily transportable.   
     
     
         13 . The system of  claim 11 , further comprising a pump inlet that introduces a cooling liquid maintained within the housing to the pump, and wherein the cooling liquid is a part of the circulatory fluid flow. 
     
     
         14 . The system of  claim 12 , wherein the evaporator induces a pressure drop in the cooling liquid to approximately 5.5 PSI, a corresponding phase change resulting in a lowered temperature of the cooling liquid. 
     
     
         15 . The system of  claim 13 , wherein the cooling liquid is water. 
     
     
         16 . The system of  claim 13 , wherein a pressure change within a fluid flow of the compressible fluid occurs within a range of approximately 20 PSI to 100 PSI. 
     
     
         17 . The system of  claim 13 , wherein a pressure change within a fluid flow of the compressible fluid involves a change to an excess of 100 PSI. 
     
     
         18 . The system of  claim 13 , wherein a pressure change within a fluid flow of the compressible fluid involves a change to less than 20 PSI. 
     
     
         19 . The system of  claim 11 , wherein the pump raises the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSI. 
     
     
         20 . The system of  claim 11 , wherein the pump raises the pressure of the circulatory fluid flow to more than 100 PSI.