Lightweight, Durable PCM Heat Exchanger for Spacecraft Thermal Control



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47th International Conference on Environmental Systems


We have built and demonstrated a proof-of-concept thermal storage system using an innovative design that enables very high thermal storage per unit mass. Thermal storage is a key technology for future spacecraft because it can reduce the size of thermal management systems by smoothing out variations in the heat load and/or heat rejection environment. This approach reduces system mass by enabling designers to size active components based on a spacecraft’s average operating conditions instead of the least favorable conditions. Heat exchangers that contain phase-change material (PCM) enable thermal storage by freezing the PCM when extra heat rejection is available and thawing it when the heat loads are high. Low-mass PCM heat exchangers are difficult to design, however, due to the large amount of additional mass needed to provide a durable heat exchanger structure and to provide low-resistance pathways for heat conduction into or out of the PCM. Our PCM heat exchanger design is based on innovative heat exchanger fabrication techniques that enable essentially direct-contact heat exchange with the PCM through a very lightweight containment structure. We have fabricated a prototypical core sample and measured its energy storage performance using paraffin PCM in thermal cycle tests that simulate operation in low-lunar orbit. The tests demonstrate very high thermal energy storage per unit mass of heat exchanger (130 kJ/kg ) in the heat exchanger core, low pressure losses, and efficient heat transfer. Based on these results, we have produced a conceptual design of a full-size PCM heat exchanger based on requirements for a manned spacecraft in low Lunar orbit. The test results and design calculations show that the PCM heat exchanger can achieve an overall PCM mass fraction greater than 50% in a 3,700 kJ thermal storage unit.


Michael Izenson, Creare LLC, USA
Jeff Cox, Creare LLC, USA
Darin Knaus, Creare LLC, USA
John Sanders, Edare Inc., USA
ICES104: Advances in Thermal Control Technology
The 47th International Conference on Environmental Systems was held in South Carolina, USA on 16 July 2017 through 20 July 2017


Thermal storage, Phase change material, Heat Exchanger