Thermal Recovery System for High‐Power Devices

ABSTRACT High‐power devices generate substantial heat that accelerates performance degradation. Conventional air‐cooling and liquid‐cooling approaches reduce overheating but simply discard the heat rather than recover it. Here we report a chip‐scale waste‐heat recovery system that integrates hydrovoltaic and thermoelectric modules to provide simultaneous cooling and power generation. The system is coupled to AlGaN deep‐ultraviolet LEDs, a model for high‐power devices because of their strong self‐heating and temperature‐dependent efficiency. The thermoelectric module harvests interfacial temperature gradients, and the hydrovoltaic module converts latent‐heat‐driven moisture flux into electricity. The evaporation strengthens thermal gradients to improve both LED efficiency and thermoelectric yield, while waste heat further promotes hydrovoltaic conversion. This system lowers the junction temperature from 160 °C to 60 °C, extends stable operation from 225 s (solder‐melt failure) to over 200 h, increases luminous power from 61.49 to 188.94 mW, and raises overall energy utilization from 0.85% to 3.06%.