Research on optimization strategies for heat switches based on helium adsorption models

Abstract Heat switches play a crucial role in cryogenic systems, regulating thermodynamic cycles or accelerating cooling processes. Among them, active gas-gap heat switches (AGGHS) are extensively employed, typically utilizing activated carbon and helium as the adsorbent-gas pair. Thermal conductance in AGGHS is controlled by driving gas adsorption or desorption through heating or cooling of the adsorbent. Due to significant variations among different activated carbons and other adsorbents, and the substantial variations in design requirements for AGGHS, systematic research on the performance optimization of AGGHS remains very challenging and is currently lacking. To address this, this study investigates optimization strategies for heat switches based on the cryogenic adsorption characteristics of helium. Specifically, by defining parameters to evaluate the filling ratio, an optimization methodology for determining the suitable operational range of AGGHS is proposed. Further, targeted optimization directions for the filling ratio are provided to address diverse application needs, such as adjusting the switching temperature range of the adsorption pump or speeding up the response time of AGGHS.