[论文解读] Intelligent radiative thermostat induced by near-field radiative thermal diode

Yang Liu, Mauro Antezza+1 more|arXiv (Cornell University)|Sep 26, 2023

Thermal Radiation and Cooling Technologies被引用 9

一句话总结

一个辐射温控器概念把被动远场冷却与近场辐射热二极管（使用氧化钒）结合起来，以在室温下将底部结构的温度维持在相变点附近并稳定热传递。

ABSTRACT

A radiative thermostat system senses its own temperature and automatically modulates heat transfer by turning on/off the cooling to maintain its temperature near a desired set point. Taking advantage of far- and near-field radiative thermal technologies, we propose an intelligent radiative thermostat induced by the combination of passive radiative cooling and near-field radiative thermal diode for thermal regulation at room temperature. The top passive radiative cooler in thermostat system with static thermal emissivity uses the cold outer space to passively cool itself all day, which can provide the bottom structure with the sub-ambient cold source. Meanwhile, using the phase-transition material vanadium dioxide, the bottom structure forms a near-field radiative thermal diode with the top cooler, which can significantly regulate the heat transfer between two terminals of the diode and then realize a stable temperature of the bottom structure. Besides, the backsided heat input of the thermostat has been taken into account according to real-world applications. Thermal performance of the proposed radiative thermostat design has been analyzed, showing that the coupling effect of static passive radiative cooling and dynamic internal heat transfer modulation can maintain an equilibrium temperature approximately locked within the phase transition region. Besides, after considering empirical indoor-to-outdoor heat flux, rendering its thermal performance closer to that of passive solar residential building walls, the calculation result proves that the radiative thermostat system can effectively modulate the temperature and stabilize it within a controllable range. Passive radiative thermostats driven by near-field radiative thermal diode can potentially enable intelligent temperature regulation technologies, for example, to moderate diurnal temperature in regions with extreme thermal swings.

研究动机与目标

• 通过辐射手段实现智能温度调控，让系统在感知和自动调节热传递方面具备自我调节能力。
• 提出一种利用被动远场冷却与基于 VO2 的近场二极管实现底部结构亚环境冷却的温控器设计。
• 分析将静态被动冷却与动态内部热传递调制耦合，如何实现温度稳定。
• 评估在现实室内到室外的热流条件下的性能，以模拟建筑墙体环境。

提出的方法

• 采用顶部被动辐射冷却器，具备静态发射率并将空间作为冷源。
• 利用氧化钒作为相变材料，与冷却器形成近场辐射热二极管。
• 分析由 VO2 相态驱动的二极管端点之间的热传递调制。
• 在热分析中加入背面热输入，以反映实际应用场景。
• 评估性能以显示 VO2 相变区域的平衡温度。
• 将结果置于室内到室外的热流背景下，以与被动太阳墙行为相关联。

实验结果

研究问题

• RQ1 被动辐射冷却器加 VO2 基近场二极管能否在室温下将底部结构温度维持在 VO2 相变区域附近？
• RQ2 静态被动冷却与动态近场热传输调制的耦合在现实热流条件下如何影响热调控？
• RQ3 辐射温控器是否能够有效调节热传递，在昼夜温差下实现稳定的平衡？

主要发现

• 系统能够在 VO2 相变区域内实现近似的平衡温度。
• 将静态被动冷却与动态内部热传递调制耦合，可提升温度稳定性。
• 考虑室内到室外热流，该设计可近似被动太阳能住宅墙的热行为。
• 辐射温控器在具有极端热波动的环境中显示出智能温度调控的潜力。