Waste heat recovery in solid-state lighting based on thin film thermoelectric generators

The waste heat of high-power light emitting diodes (LEDs) is well localized and can be efficiently harvested in contrast to incandescent or fluorescent light sources. Compact thin film thermoelectric generators can accumulate the high-density heat flux from the LED chip and convert it into usable electrical power. We designed and analyzed a thermal management setup with high power LED and embedded thin film thermoelectric generators. The available thermal gradient of approximately 50 K allows conversion of the LED waste heat with an overall efficiency of 1%. We present an application of the active cooling powered by the harvested waste heat. The compact flat shape of the thin film thermoelectric generators allows an instant upgrade of the existing LED-based luminaries available on the market.