Steady-State Parametric Optimization and Transient Characterization of Heat Flow Regulation With Binary Diffusion

Thermal regulators and switches are nonlinear devices that can greatly aid in the management of transient and/or spatially varying heating events. Various physical mechanisms have been harnessed to achieve nonlinear and switchable thermal behavior, though device characteristics are often evaluated in terms of steady-state performance only. Accurately capturing the transient behavior of these devices is a crucial missing link required for assessing the effectiveness of implementation in real-world scenarios. Here, we explore the physics of binary vapor diffusion through a noncondensable gas cavity as a promising mechanism for high-resistance contrast thermal regulation. Through a parametric steady-state optimization, we present a roadmap for future designs that can potentially reach switching ratios of up to 14.5. In addition, we perform a transient investigation to characterize the thermal response time of the device. The device possesses an extremely desirable attribute under certain transient heat loads, where the effective switching ratio appears significantly greater than the steady-state ratio due to a temporary increase in the OFF-state resistance immediately after switching. This work informs future experimental efforts for design optimization of binary-diffusion-based regulators and establishes simple modeling schemes to approximate device performance in system-level regulation scenarios.