Liquid-gas hydrogen energy storage unit for the 15–17 K temperature range using an expansion volume at room temperature

• Published in: Applied thermal engineering Vol. 125; pp. 1239 - 1252
• Main Authors: Borges de Sousa, P., Martins, D., Linder, M., Noite, J., Bonfait, G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier BV 01-10-2017
• Subjects: Chains; Energy storage; Evaporative cooling; Fluids; Heating; Hydrogen; Hydrogen storage; Hydrogen-based energy; Latent heat; Liquid hydrogen; Mathematical models; Regeneration; Room temperature; Temperature; Thermal analysis; Thermal energy
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.06.134

In this paper, we describe a thermal energy storage unit able to absorb 400 J between 15 K and 17 K using hydrogen as the working fluid. This prototype was studied to integrate a 300 K-50 mK (Nota: diferents units for the two numbers) cryogenic chain proposed for the ATHENA mission of European Space Agency (ESA) and its goal is to avoid the heat burst on the 15 K stage induced by the periodic regeneration of the 0.3 K cooler. It consists of a small (≈17.5 cm3) and light copper cell containing liquid hydrogen connected to an expansion volume (≈56 L) at room temperature. When heat is delivered to this cell during the regeneration phase of the 0.3 K cooler, the hydrogen evaporates and is stored in the gaseous state in the expansion volume. We show that, due to the relatively high latent heat of evaporation of H2, such a liquid-gas ESU seems to be the most compact and light solution with respect to the low temperature part. The tests performed to show the compliance of our device with ESA thermal requirements are described and analyzed. In particular, 400 J are applied on this cell within 30 min with a heating power peak reaching 1 W during two minutes without exceeding 17 K. We show that the results agree with a thermal model previously developed for similar liquid-gas ESU. A 21-h regeneration phase, consisting in the recondensation of H2 gas in the low temperature cell, follows this 400 J absorption consisting in the recondensation of H2 gas in the low temperature cell. During this phase, the heat loads on the various thermal interfaces used to cool and condense the H2 gas were monitored to insure that they do not exceed the thermal budget. This test campaign allowed us to conclude that the low temperature part of this device seems compatible with thermal constraints needed for its integration in the proposed cryogenic chain.