Effective thermal management of heat sources in sustainable energy devices using a compact flat thermosyphon

Thermal management is critical in improving the efficiency, lifespan, and reliability of sustainable energy devices such as LEDs, batteries, and solar cells. The compact flat thermosyphon (CFT) is more reliable for the effective thermal management of multiple heat sources in energy-intensive devices. A comprehensive study on the thermal performance of a two-phase CFT is conducted in the present study. The volume of the CFT is 72 × 24 × 15 mm3 and is made up of copper. The thermal performance of the CFT is analyzed by varying the filling ratio (20%, 50%, 80%), working fluid (acetone, ethanol, water), number of heat sources, and condenser surface wettability. The best-performing filling ratio is found to be 50%. Water is the best performing working fluid over a wide range of heat fluxes (10 – 70 W/cm2) due to high heat capacity, latent heat, and low vapor pressure. The CFT can safely cool up to four heat sources of size 12 × 24 mm2 at a heat flux of 30 W/cm2 each. The lifespan of the devices can be increased by 2.49 – 6.62 times when the CFT is used to cool multiple heat sources instead of a cold plate. The superhydrophobic condenser surface further improved the thermal performance of the CFT by 28 – 47% because of the quicker return of condensate and dropwise condensation.