"220V Cooling Fan" is due to the temperature difference between the thermal conductor and the adjacent material or space, so that the thermal conductor of heat will be sent out in the form of electromagnetic waves. The higher the surface temperature of the heat sink, the rougher the surface, the higher the rate of black surface, the radiation energy capacity radiator stronger. Therefore, the majority of "220V Cooling Fan" radiators have been black oxide treatment, is in order to increase the capacity of the thermal radiation. Conduction and convection, heat transfer is carried out by solid or liquid, and radiative heat transfer without any substance as a medium. Thermal radiation is electromagnetic radiation due to its own temperature caused. Absolute temperature "220V Cooling Fan" radiative heat transfer is proportional to its body. For radiation heat transfer, there is Stefan Boltzmann law exists.