The existing solution used by the team was developed by Aavid in Bologna, Italy in 2012. It was constructed from formed aluminum fins brazed to a baseplate. During the tests for the competition in 2013, the team observed that in operation the heatsink was “too cold to be true”. At a weight of 0.74 kg (1.6 pounds), the cooling solution was clearly oversized, overweight and over performing for the latest reduced heat load.
We needed to very quickly re-optimize the design for minimum weight while maintaining adequate thermal performance. Analysis showed that we could significantly reduce the fin height and pitch. The team decided to stick with the brazed assembly process, so the base and fin thicknesses were set at the minimums required for brazing.
Modeling predicted that Aavid could to reduce the weight of the thermal solution by 50% reaching 0.36 kg (0.8 pounds) while meeting the thermal requirements. Aavid rapidly formed the fins, used CNC to machine the base, brazed together the entire structure, sand-blasted it, and applied a black anodize finish to enhance radiated transfer.
Solar Team Twente completed the test and the results were exactly as Aavid predicted - great thermal performance at half the weight. Best of luck to Solar Team Twente in Australia!