Method and apparatus for controlling cooling with coolant at a subambient pressure

Abstract

According to one embodiment of the invention a method for controlling cooling of a heat-generating structure disposed in an environment having an ambient pressure includes providing a fluid coolant and reducing the pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure. The method further includes boiling and vaporizing coolant to absorb heat from the heat-generating structure by bringing the coolant into thermal communication with the heat generating structure. The method also includes measuring a parameter indicative of a pressure of the coolant and adjusting the pressure of the coolant in response to control the cooling of the heat-generating structure.

1 . An apparatus, comprising a heat-generating structure disposed in an environment having an ambient pressure and a cooling system for removing heat from said heat-generating structure, said cooling system including: 
 a fluid coolant;    structure that reduces a pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure;    structure that directs a flow of the coolant in the form of a liquid in a manner causing the liquid coolant to be brought into thermal communication with the heat-generating structure, the heat from the heat-generating structure causing the liquid coolant to boil and vaporize so that the coolant absorbs from the heat-generating structure as the coolant changes state;    a pressure transducer disposed within the passageway and operable to measure a pressure of the coolant in the passageway;    a controller operable to receive the pressure of the coolant in the passageway and generate a control signal based at least in part on a desired temperature of a portion of the heat-generating structure and the amount of heat generated by the heat-generating structure;    a positive displacement pump responsive to the control signal operable to adjust a pressure of the coolant to control cooling of the heat-generating structure;    wherein the heat-generating structure includes a passageway having a surface that extends along a length of the passageway; and    wherein heat generated by the heat-generating structure is supplied to the surface of the passageway along the length of the surface, the portion of the coolant flowing through the passageway and engaging the surface so as to absorb heat from the surface.    
   
   
       2 . A method for controlling cooling of a heat-generating structure disposed in an environment having an ambient pressure, comprising: 
 providing a fluid coolant;    reducing a pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure;    boiling and vaporizing the coolant to absorb heat from the heat-generating structure by bringing the coolant into thermal communication with the heat-generating structure;    measuring a parameter indicative of a pressure of the coolant; and    adjusting the pressure of the coolant in response to the measuring to control the cooling of the heat-generating structure.    
   
   
       3 . A method according to  claim 2 , wherein adjusting the pressure of the coolant comprises adjusting the pressure of the coolant based at least in part on a heat load of the heat-generating structure.  
   
   
       4 . A method according to  claim 2 , wherein the parameter indicative of a pressure of the coolant is one of pressure of the coolant and a temperature of the coolant.  
   
   
       5 . A method according to  claim 2 , wherein adjusting the pressure of the coolant comprises adjusting the pressure of the coolant by a positive displacement pump.  
   
   
       6 . A method according to  claim 2 , wherein adjusting the pressure of the coolant comprises adjusting the pressure of the coolant by a linear actuated bellows.  
   
   
       7 . A method according to  claim 2 , including: 
 configuring the heat-generating structure to include a passageway having a surface that extends along a length of the passageway;    supplying the heat generated by the heat generating structure to the surface of the passageway along the length thereof; and    causing the portion of the coolant to flow through the passageway and engage the surface.    
   
   
       8 . A method according to  claim 2 , wherein adjusting the pressure of the coolant comprises adjusting the pressure of the coolant based in part on a desired temperature of a portion of the heat-generating structure.  
   
   
       9 . A method according to  claim 7 , wherein the parameter indicative of a pressure of the coolant is a parameter indicative of a pressure of the coolant in the passageway.  
   
   
       10 . A method according to  claim 2 , including selecting for use as the coolant one of water, methanol, a fluorinert, and a mixture of water and ethylene glycol.  
   
   
       11 . A method according to  claim 2 , including circulating the coolant through a flow loop.  
   
   
       12 . A method according to  claim 11 , including configuring the loop to include a heat exchanger for removing heat from said coolant so as to condense the coolant.  
   
   
       13 . A method according to  claim 12 , including causing the heat exchanger to transfer heat from the coolant to a further medium having an ambient temperature that is less than the boiling temperature of the coolant at the pressure of the coolant.  
   
   
       14 . An apparatus, comprising heat-generating structure disposed in an environment having an ambient pressure, and a cooling system for removing heat from the heat-generating structure, the cooling system including: 
 a fluid coolant;    structure that reduces a pressure of the coolant to a subambient pressure at which the coolant has a boiling temperature less than a temperature of the heat-generating structure;    structure that directs a flow of the coolant in a manner causing the liquid coolant to be brought into thermal communication with the heat-generating structure, the heat from the heat-generating structure causing the liquid coolant to boil and vaporize so that the coolant absorbs heat from the heat-generating structure as the coolant changes state;    a transducer in operative communication with the coolant and operable to measure a parameter indicative of a pressure of the coolant;    a controller operable to receive the parameter indicative of a pressure of the coolant and generate a control signal; and    structure responsive to the control signal that is operable to adjust a pressure of the coolant to control cooling of the heat-generating structure.    
   
   
       15 . An apparatus according to  claim 14 , wherein the controller is further operable to generate a control signal based at least in part on a desired temperature of the heat-generating structure.  
   
   
       16 . An apparatus according to  claim 14 , wherein the controller is further operable to generate a control signal based at least in part on a heat load of the heat-generating structure.  
   
   
       17 . An apparatus according to  claim 14 , wherein the transducer is one of a pressure transducer and a temperature transducer.  
   
   
       18 . An apparatus according to  claim 14 , 
 wherein the heat-generating structure includes a passageway having a surface that extends along a length of the passageway; and    wherein heat generated by the heat generating structure is supplied to the surface of the passageway along the length of the surface, the portion of the coolant flowing through the passageway and engaging the surface so as to absorb heat from the surface.    
   
   
       19 . An apparatus according to  claim 18 , wherein the transducer is a pressure transducer disposed in the passageway.  
   
   
       20 . An apparatus according to  claim 14 , wherein the structure responsive to the control signal is a positive displacement pump.  
   
   
       21 . An apparatus according to  claim 14 , wherein the structure responsive to the control signal is a linear actuated bellows.  
   
   
       22 . An apparatus according to  claim 14 , wherein the structure that directs a flow of the coolant is configured to circulate the coolant through a flow loop.  
   
   
       23 . An apparatus according to  claim 22 , including a heat exchanger for removing heat from the coolant flowing through the loop so as to condense the coolant to a liquid.  
   
   
       24 . An apparatus according to  claim 23 , wherein the heat exchanger transfers heat from the coolant to a further medium having an ambient temperature less than the boiling temperature of the coolant at the pressure of the coolant.