Advanced Reversible Cryogenic Thermal Energy Storage (ARCTES)

ORBITEC proposes to develop the Advanced Reversible Cryogenic Thermal Energy Storage (ARCTES) system, which will provide temporary backup cooling for circulating helium gas coolant in high-temperature superconducting (HTS) systems for naval applications. The ARCTES will rely on an initially-frozen cryogen to absorb heat from the passing helium gas through a heat exchanger device. As the working cryogen continues to absorb heat, it will warm to its melting point, melt, and then continue to warm as a liquid and evaporate to the vapor phase. The ARCTES provides a compact, lightweight, and simple means of passively storing cooling capacity. For purposes of comparison, the current state-of-the-art backup cooling system relies on the heat of vaporization of liquid nitrogen, which provides approximately 200 joules per gram (J/g) of cooling capacity. The ARCTES system will improve upon this figure by 50%, approaching 300 J/g of cooling capacity. The ARCTES system has the additional advantages of requiring neither LN2 resupply nor a vent to atmosphere for boil-off gas, and of being passively reversible. ORBITEC has extensive experience in the formation and management of solid cryogens as part of our propulsion system development, and we are well-qualified to perform this work.