Theoretical consideration
The rate of heat transfer between the hot side of the module and
the surface of the heat sink can be calculated as
where R1 ¼ L=kAs; k is the heat conductivity of the aluminum; L is
the thickness of the heat sink base; As is the contact surface area
between the module and the heat sink base; Tb is the temperature
of the base which will be the same as the temperature of the hot
side of the module assuming no losses through the heat sink
compound; T1 is the temperature of the other side of the base.
The rate of heat transfer from the other side of the base through
the fins to the air can be calculated as