Sub-ambient refrigerating cycle

Abstract

According to one embodiment of the invention, a method for cooling heat-generating structure disposed in an environment having an ambient pressure includes providing a fluid refrigerant and reducing a pressure of the refrigerant to a first sub-ambient pressure at which the refrigerant has a boiling temperature less than a temperature of the heat-generating structure. The method also includes bringing the refrigerant at the first sub-ambient pressure into thermal communication with the heat-generating structure, so that the refrigerant boils and vaporizes to thereby absorb heat from the heat-generating structure. The method further includes increasing a pressure of the vaporized refrigerant above the first sub-ambient pressure to a second sub-ambient pressure.

1 . A method for cooling heat-generating structure disposed in an environment having an ambient pressure, comprising the acts of: 
 providing a fluid refrigerant;    reducing a pressure of the refrigerant to a first sub-ambient pressure at which the refrigerant has a boiling temperature less than a temperature of the heat-generating structure;    bringing the refrigerant at the first sub-ambient pressure into thermal communication with the heat-generating structure, so that the refrigerant boils and vaporizes to thereby absorb heat from the heat-generating structure; and    increasing a pressure of the vaporized refrigerant above the first sub-ambient pressure to a second sub-ambient pressure.    
   
   
       2 . The method of  claim 1 , and further comprising the act of selecting for use as the refrigerant one of water and a mixture of water and ethylene glycol.  
   
   
       3 . The method of  claim 1 , and further comprising the act of circulating the refrigerant through a flow loop while maintaining the pressure of the refrigerant within a range having an upper bound less than the ambient pressure.  
   
   
       4 . The method of  claim 3 , and further comprising the act of configuring the loop to include a heat exchanger for removing heat from the refrigerant so as to condense the refrigerant to a liquid.  
   
   
       5 . The method of  claim 4 , and further comprising the act of causing the heat exchanger to transfer heat from the refrigerant to a further medium having an ambient temperature that is less than the boiling temperature of the refrigerant at the second sub-ambient pressure.  
   
   
       6 . The method of  claim 5 , and further comprising the act of selecting for use as the medium one of ambient air and ambient water.  
   
   
       7 . The method of  claim 3 , and further comprising the act of configuring the loop to include a first pump for circulating the refrigerant through the loop.  
   
   
       8 . The method of  claim 4 , and further comprising the act of removing any air accumulated in the heat exchanger from any leak in the loop.  
   
   
       9 . The method of  claim 8 , wherein the act of removing any air comprises condensing at least some vapor to liquid.  
   
   
       10 . The method of  claim 8 , where the act of removing any air comprises raising a pressure of the air above the ambient pressure and venting the air at the raised pressure to the environment.  
   
   
       11 . The method of  claim 3 , and further comprising accumulating any liquid not evaporated by the heat-generating structure and within the loop.  
   
   
       12 . The method of  claim 11 , and further comprising pumping the accumulated liquid back into the loop for further thermal communication with the heat-generating structure.  
   
   
       13 . The method of  claim 1 , including the act of configuring the heat-generating structure to include a plurality of sections that each generate heat; and 
 wherein the act the of bringing the cooling into thermal communication with the heat-generating structure includes the act of bringing respective portions of the coolant into thermal communication with the respective sections of the heat-generating structure.    
   
   
       14 . The method of  claim 13 , and further comprising the acts of: 
 providing a plurality of orifices; and    causing each of the portions of the refrigerant to pass through the respective orifice before being brought into thermal communication with the respective section of the heat-generating structure.    
   
   
       15 . The method of  claim 14 , and further comprising the act of configuring the orifices to have respective different sizes or to cause the portions of the refrigerant to have respective different volumetric flow rates.  
   
   
       16 . An apparatus, comprising a heat-generating structure disposed in an environment having an ambient pressure, and a refrigeration system for removing heat from the heat-generating structure, the refrigeration system including: 
 a fluid refrigerant maintained at a pressure less than the ambient pressure at which the refrigerant has a boiling temperature less than a temperature of the heat-generating structure;    a structure that directs a flow of the refrigerant in the form of a liquid at the sub-ambient pressure in a manner causing the liquid refrigerant to be brought into thermal communication with the heat-generating structure, the heat from the heat-generating structure causing the liquid refrigerant to boil and vaporize so that the refrigerant absorbs heat from the heat-generating structure as the refrigerant changes state; and    a compressor that increases the pressure of the vaporized refrigerant to a second sub-ambient pressure.    
   
   
       17 . The apparatus of  claim 16 , wherein the refrigerant is one of water and a mixture and ethylene glycol.  
   
   
       18 . The apparatus of  claim 16 , wherein the structure that directs a flow of the refrigerant is configured to circulate the refrigerant through a flow loop while maintaining the pressure of the refrigerant within a range having an upper bound less than the ambient pressure.  
   
   
       19 . The apparatus of  claim 18 , further comprising a heat exchanger for removing heat from the refrigerant flowing through the loop at the second sub-ambient pressure so as to condense the refrigerant to a liquid.  
   
   
       20 . The apparatus of  claim 19 , wherein the heat exchanger transfers heat from the refrigerant at the second sub-ambient pressure to a further medium having an ambient temperature greater than a temperature of the heat-generating structure.  
   
   
       21 . The apparatus of  claim 20 , wherein the medium is one of ambient air and ambient water.  
   
   
       22 . The apparatus of  claim 19 , wherein the structure that circulates the coolant through the loop includes a pump that effects the circulation of the coolant.  
   
   
       23 . The apparatus of  claim 16 , and further comprising an accumulator for accumulating liquid that is not condensed by the heat-generating structure.  
   
   
       24 . The apparatus of  claim 23 , and further comprising a second pump for returning the accumulated liquid to the heat-generating structure.  
   
   
       25 . The apparatus of  claim 19 , and further comprising an air removal structure attached to the heat exchanger for removing any air trapped in the heat exchanger from leaks in the refrigeration structure.  
   
   
       26 . The apparatus of  claim 25 , wherein the air removal structure comprises: 
 a second compressor to raise the pressure of the air;    a second heat exchanger to remove heat from the air;    a separator for separating the air into liquid and gas components; and    a vent operable to vent the gas component to the environment.    
   
   
       27 . The apparatus of  claim 19 , wherein the heat exchanger exchanges heat with an environment having a temperature greater than a temperature of the heat-generating structure.  
   
   
       28 . The apparatus of  claim 16 , 
 wherein the heat-generating structure includes a plurality of sections that each generate heat; and    wherein the structure for directing the flow of the refrigerant brings respective portions of the refrigerant into thermal communication with the respective sections of the heat-generating structure.    
   
   
       29 . The apparatus of  claim 16 , wherein the structure for directing the flow of the fluid includes a plurality of orifices and causes each of the portions of the refrigerant to pass through the respective orifice before being brought into thermal communication with the respective section of the heat-generating structure.  
   
   
       30 . The apparatus of  claim 29 , wherein the orifices have respective different sizes in order to cause the portions of the refrigerant to have respective different volumetric flow rates.