The Development of Foam-Enabled Phase Change Material Heat Exchangers

High power electronics are limited by conventional thermal management technologies, particularly in space-based applications. Phase change material (PCM)-based heat exchangers dampen peak heat loads using latent heat, allowing sizing of the thermal management system based on the average heat load rather than the peak heat load. PCMs, often paraffin wax, inherently suffer from low thermal conductivity (~0.2 W/m-K); the resulting thermal resistance is too high for effective dampening. The performance of the PCM can be enhanced by the addition of an extended surface. This work will discuss both conventional and additively manufactured open celled metal foam as extended surfaces to reduce thermal resistance and enhance performance of PCM heat exchangers. Conventional metal foam has been manufactured for more than fifty years and exhibit an order of magnitude better thermal performance than the most common extended surface, machined fins, as well as affording various manufacturability advantages. The more recent development of additively manufactured foam allows for more complex foam morphology and therefore enhanced performance, ideally keeping pace with the rapidly developing thermal management needs of the aerospace industry.