Cooling Systems for Downhole Tools

Abstract

A cooling system for a downhole tool includes an insulating chamber disposed in the downhole tool, wherein the insulating chamber is adapted to house an object to be cooled; a thermoacoustic cooler disposed in the downhole tool, wherein the thermoacoustic cooler has a cold end configured to remove heat from the insulating chamber and a hot end configured to dissipate heat; and an energy source for generating an acoustic wave in the thermoacoustic cooler. A method for constructing a downhole tool includes disposing a to-be-cooled object in an insulating chamber in the downhole tool; and disposing a thermoacoustic cooler in the downhole tool proximate the insulating chamber such that the thermoacoustic cooler is configured to remove heat from the insulating chamber.

1 . A cooling system for a downhole tool, comprising:
 an insulating chamber disposed in the downhole tool, wherein the insulating chamber is adapted to house an object to be cooled;   a thermoacoustic cooler disposed in the downhole tool, wherein the thermoacoustic cooler has a cold end configured to remove heat from the insulating chamber and a hot end configured to dissipate heat; and   an energy source for generating an acoustic wave in the thermoacoustic cooler.   
   
   
       2 . The cooling system of  claim 1 , wherein the thermoacoustic cooler comprises:
 a resonator containing a refrigerant; and   a plurality of plates forming a stack to exchange heat with the refrigerant.   
   
   
       3 . The cooling system of  claim 1 , wherein the thermoacoustic cooler is a pulse-tube refrigerator. 
   
   
       4 . The cooling system of  claim 2 , wherein the resonator has a substantially cylindrical shape and the plurality of plates are stacked along an axial direction of the resonator. 
   
   
       5 . The cooling system of  claim 2 , wherein the resonator comprises a spherical-shaped portion connected to a tube-shaped portion. 
   
   
       6 . The cooling system of  claim 2 , wherein the resonator comprises a tube structure forming a loop having a length that is an integer multiple of a wavelength of the acoustic wave. 
   
   
       7 . The cooling system of  claim 2 , wherein the refrigerant is one selected from the group consisting of helium, argon, a mixture of argon and helium, and liquid sodium. 
   
   
       8 . The cooling system of  claim 1 , wherein the energy source comprises a loudspeaker. 
   
   
       9 . The cooling system of  claim 1 , wherein the energy source comprises a thermal generator. 
   
   
       10 . The cooling system of  claim 1 , further comprising a heat pipe disposed between the cold end of the thermoacoustic cooler and the insulating chamber, wherein the heat pipe is adapted to conduct heat from the insulating chamber to the cold end of the thermoacoustic cooler. 
   
   
       11 . A method for constructing a downhole tool, comprising:
 disposing a to-be-cooled object in an insulating chamber in the downhole tool; and   disposing a thermoacoustic cooler in the downhole tool proximate the insulating chamber such that the thermoacoustic cooler is configured to remove heat from the insulating chamber.   
   
   
       12 . The method of  claim 11 , wherein the thermoacoustic cooler comprises:
 a resonator containing a refrigerant; and   a plurality of plates forming a stack to exchange heat with the refrigerant.   
   
   
       13 . The method of  claim 12 , wherein the refrigerant is one selected from the group consisting of helium, argon, a mixture of argon and helium, and liquid sodium. 
   
   
       14 . The method of  claim 12 , wherein the resonator has a substantially cylindrical shape and the plurality of plates are stacked along an axial direction of the resonator. 
   
   
       15 . The method of  claim 12 , wherein the resonator comprises a spherical-shaped portion connected to a tube-shaped portion. 
   
   
       16 . The method of  claim 12 , wherein the resonator comprises a tube structure forming a loop having a length that is an integer multiple of a wavelength of the acoustic wave. 
   
   
       17 . A method for cooling a portion of a downhole tool, comprising:
 providing a thermoacoustic cooler in the downhole tool proximate the portion to be cooled; and   energizing the thermoacoustic cooler to generate an acoustic wave such that heat is removed from the portion to be cooled.   
   
   
       18 . The method of  claim 17 , wherein the energizing is by supplying electrical power from a source selected from the group consisting of a surface electrical source, a downhole battery, and a downhole power generator.