Fast Adaptive Thermal Buffering by a Passive Open Shell Based on Transformation Thermodynamics

Abstract

By using transformation thermodynamics, an open, adaptive thermal buffer shell (TBS) is designed and experimentally implemented with natural materials (layered copper and expanded polystyrene [EPS]). The TBS can store excessive heat flux quickly in the shell and release it slowly when it is needed, which also has some distinctive features: first it is a buffer shell that can avoid external extremes in temperature (either high or low) and also provide a relatively stable temperature for the interior of the shell when the temperature outside the shell has some fluctuations; second the TBS is not thermally insulated (with holes connected to the outside world) and the buffering effect of the TBS originates from the heat recycling mechanics, not thermal insulation; third the TBS has a short response time and the temperature inside the shell can be quickly adjusted according to the average temperature outside the shell; fourth the TBS is a passive device. Unlike traditional air conditioning, the TBS can work without an external power supply. The TBS will have many applications in energy recycling systems, smart heat controlling systems, and passive heat self-adaptation systems. Numerical simulations and experimental demonstrations are given to verify the function of the TBS.In the times of energy shortage, the recycling of heat energy becomes more and more important. Therefore, how to handle the heat dissipation, the heat storage, and thereby give an effective control of heat flux becomes an important subject. For some applications, it is desirable for heat to dissipate as quickly as possible, such as the heat generated on chips. For other applications, though, enough heat must be retained to resist cold. However, heat generated in the first case is usually wasted and seldom reused for the second case because these two situations occur

Active Thermal Metasurfaces for Remote Heating/Cooling by Mimicking Negative Thermal Conductivity

“…To expand the range of thermal conductivities, a few novel thermal materials with artificial structures have been proposed, often referred to as thermal metamaterials and metasurfaces. [1][2][3] As thermal metamaterials and metasurfaces can achieve a more diverse and wider range of thermal conductivity, such as, inhomogeneous anisotropic values, tunable thermal conductivity, and even a thermal conductivity tending to infinity, [4] the control of temperature fields has been drastically improved by achieving thermal DOI: 10.1002/adma.202210981 cloaking, [5][6][7][8][9] thermal camouflage, [10][11][12][13][14][15][16] thermal concentrator, [17] thermal rectification and thermal diodes, [18][19][20][21] thermal Hall effect, [22][23][24] thermal encoding, [25] thermal buffering, [26] and thermal lensing. [27][28][29][30] These findings broaden the scope of thermodynamic research and pave the way for the realization of unusual thermal conductivity values.…”

Experimental Demonstration of Thermal Chameleonlike Rotators with Transformation-Invariant Metamaterials

“…With the goal of enhancing the adaptability of thermal metamaterials, we propose a mechanism grounded in thermal transformation-invariant metamaterials [56,57], which exhibit highly anisotropic thermal conductivities-0 W m −1 K −1 in one direction and ∞ W m −1 K −1 in the other [58][59][60]. Notably, transformation-invariant (i.e., highly anisotropic) metamaterials have elicited widespread interest in diverse fields such as electromagnetism [61,62] and acoustics [63,64].…”

Theory for Chameleonlike Thermal Rotators: Extremely Anisotropic Conductivity

“…To improve intelligence, we propose a mechanism based on thermal transformation-invariant metamaterials [11,12], whose thermal conductivities are highly anisotropic [13][14][15], i.e., 0 W m −1 K −1 in one direction and ∞ W m −1 K −1 in the other. Transformation-invariant (i.e., highly anisotropic) metamaterials have aroused broad interest in various fields, such as electromagnetism [16,17] and acoustics [18,19].…”