The main issue concerning the power LEDs is the thermal power generated during operation, which increases the junction temperature affecting the operating characteristics of the power LED and casing the reduction of: the useful life of the components, the luminous flux, the light efficiency and the forward voltage. Moreover there is an increase of the fundamental wavelength of emitted light. Purpose of this study is to compare the heat transfer performances of finned surfaces, which represent a commonly used passive techniques for heat removal in the field of lighting power LED, with an innovative liquid cooling placing the LED in an enclosure filled with dielectric refrigerant.