Supercooling-enabled giant and tunable thermal rectification ratio of a phase change thermal diode

TL;DR

This paper presents a supercooling-enabled phase change thermal diode with a record-high rectification ratio of 3.0, tunable over a broad temperature range, advancing thermal management technologies.

Contribution

It introduces a scalable, tunable PCTD model with supercooling effects, achieving unprecedented rectification ratios and broad temperature bias control.

Findings

Achieved a thermal rectification ratio of 3.0 at ambient temperature.

Supercooling extends the workable temperature bias range.

Manual supercooling release enables tuning within 10-33°C.

Abstract

Phase change thermal diodes (PCTD) suffer from fairly low thermal rectification ratio, which hampers their widespread utilization as thermal management and control units for cutting-edge technologies, encompassing photovoltaics, thermoelectric modules, batteries and other miniaturized electronic products, etc. It is thus indispensable to explore a high-performance PCTD. Herein, a tunable and scalable PCTD is modeled, theoretically analyzed, fabricated and experimentally executed, accessing an unprecedented giant thermal rectification ratio of 3.0 at ambient temperature. With optimized length ratio and feasible assembly of two phase change terminals, the emerging physical states of thermal media continuously contribute to align the convective-intensified thermal conductive profiles, mandatory for heat flux manipulation within temperature bias of 10~40 {\deg}C. The most significant finding discloses the fact that supercooling elongates the overall workable temperature bias range, while manual supercooling release allows to tune the thermal rectification ratio at any temperature bias within 10~33 {\deg}C. Integrating the conventional asymmetric thermal transport mechanism with state-specific heat transfer hysteresis helps establish the novel governing mechanism.