EPD-11_Thermal

							 Thermal design of
Electronic equipment



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Heat transfer
  Introduction…




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Basics
   TC =Tcond+Ttrf+TA

       TC = Temperature of component
       Tcond = Temperature rise due to conducting the
        heat to the cooling surface (mainly conduction)
       Ttrf = Temperature rise due to transferring the
        heat from cooling surface to the medium
       TA = ambient temperature


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Conduction




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Conduction

   P = Heat power being conducted in W
   K = Thermal conductivity of the rod W/m0C
       Eg: Cu ->395
   L = Length of the rod in m
   T1 = Temperature at source in 0C
   T2 = Temperature at sink in 0C

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Electrical analogy
   ∆T = T1 - T2 = Rth * P
   Rth = L / ( A * k) -
    thermal resistance in
    0C/W




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Convection and radiation
   Molecules change their position




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UNNI A M,SOE,CUSAT