Thermal Buffering of Downhole Equipment with Phase Change Material

Abstract

A downhole assembly may include a housing containing a heat-producing component in thermal communication with a thermal buffering component. The thermal buffering component includes a container ( 232 ) having a phase change material disposed therein that is selected to have a phase change at or below a selected temperature.

1 . A downhole assembly comprising:
 a housing;   an electronic component disposed within the housing, wherein the electronic component can generate heat; and   a first phase change material packaged in a first container comprising a first microporous material and disposed within the housing in thermal communication with the electronic component such that the heat generated by the electronic component can transfer to the first phase change material, the first phase change material having a phase change at a temperature at or below a first temperature.   
     
     
         2 . The downhole assembly of  claim 1 , further comprising a second phase change material packaged in a second container comprising a second microporous material and disposed within the housing in thermal communication with the electronic component such that the heat generated by the electronic component can transfer to the second phase change material, the second phase change material having an phase change at a temperature that is at or below a second temperature and different than the phase change temperature of the first phase change material. 
     
     
         3 . The downhole assembly of  claim 1 , wherein the first phase change material changes from solid to liquid, liquid to gas, or solid to gas at a temperature at or below the first temperature. 
     
     
         4 . The downhole assembly of  claim 2 , wherein the second phase change material changes from solid to liquid, liquid to gas, or solid to gas at a temperature at or below the second temperature. 
     
     
         5 . The downhole assembly of any of  claim 1 , wherein each of the first and second temperatures is at or below a predetermined maximum operating temperature of the electronic component. 
     
     
         6 . The downhole assembly of  claim 1 , wherein the first or second microporous material comprises a microporous polytetrafluoroethylene material, a microporous film or membrane, a laminate, or a coated fabric. 
     
     
         7 . The downhole assembly of  claim 1 , wherein the first phase change material is included at a mass sufficient to increase operating time of the electronic component at or below the first temperature by at least about 10%. 
     
     
         8 . The downhole assembly of  claim 2 , wherein the first phase change material and the second phase change material are included at a combined mass sufficient to increase operating time of the electronic component at or below a predetermined maximum operating temperature of the electronic component by at least about 10%. 
     
     
         9 . A method comprising:
 providing a downhole assembly comprising a housing; an electronic component disposed inside the housing; and a first phase change material disposed inside the housing;   placing the first phase change material in thermal communication with the electronic component; and   absorbing heat generated by the electronic component by a phase change of the first phase change material at or below a first temperature.   
     
     
         10 . The method of  claim 9 , wherein the downhole assembly further comprises a second phase change material disposed inside the housing; the method further comprising:
 placing the second phase change material in thermal communication with the electronic component or the first phase change material; and   absorbing the heat generated by the electronic component by a phase change of the second phase change material at or below a second temperature.   
     
     
         11 . The method of  claim 9 , further comprising automatically stopping operation of the electronic component when a temperature inside the housing reaches the first or second temperature. 
     
     
         12 . The method of  claim 9 , further comprising stopping operation of the electronic component at a time point calculated to be at or before a temperature in the housing reaches the first or second temperature. 
     
     
         13 . The method of  claim 9 , wherein the first phase change material is provided at a mass sufficient to increase operating time of the electronic component at or below the first temperature by at least about 10%. 
     
     
         14 . The method of  claim 10 , wherein the first phase change material and the second phase change material are provided at a combined mass sufficient to increase operating time of the electronic component at or below a predetermined maximum operating temperature of the electronic component by at least about 10%. 
     
     
         15 . The method of  claim 9 , wherein each of the first and second temperatures is at or below a predetermined maximum operating temperature of the electronic component.