Application of Radiative Cooling in MEMS Thermoelectric Power Generation

Hu, Zhiyu; Mu, Erzhen

doi:10.1007/978-981-19-6609-5_6

Cited by 1 publication

(1 citation statement)

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“…This effect is significant in nanoscale materials, where the mismatch between the phonon spectra of different materials at an interface results in asymmetric thermal transport. The ability to rectify heat flow is crucial for the development of advanced thermoelectric devices, − thermal diodes, , thermal transistors ,− and thermal logic gates. − Thermal rectification can be described as a nonlinear and asymmetric process where the thermal characteristics of a material along a specific axis depend on the direction of the temperature gradient or the heat current . In solid-state systems, various mechanisms have previously been proposed to achieve thermal rectification.…”

Section: Introductionmentioning

confidence: 99%

Far-Field Radiative Thermal Rectification Based on Asymmetric Emissivity

Ng,

El Sachat,

Jaramillo-Fernandez

et al. 2023

ACS Appl. Opt. Mater.

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This experimental study investigates thermal rectification via asymmetric far-field thermal radiation on a fused silica slab. An asymmetrical distribution of surface emissivity is created over the device by partially covering the fused silica with a 100 nm thick aluminum film. The slab is subjected to a thermal bias, and when this bias is reversed, a small temperature difference is observed between the different configurations. This temperature difference arises from the difference in emissivity between the aluminum layer and fused silica, resulting in the transfer of thermal energy to the surrounding environment through radiation. Experimental findings are supported by finite element simulations, which not only confirm the measured values but also provide valuable insights into the rectification efficiency of the system. The rectification efficiency is found to be approximately 50% at room temperature for a thermal bias of 140 K. Simulations, which are performed by considering different environmental conditions experienced by the radiation and free convection processes, provide further insight into the underlying thermal rectification mechanism. These simulations consider an environmental temperature of 4 K for thermal radiation and an ambient temperature of 294 K for free convection and reveal an enhanced rectification effect with a rectification efficiency up to 600% when a thermal bias of 195 K is applied. This result emphasizes the significance of considering both convection and radiation in the thermal management and rectification of asymmetric systems. The outcomes of this study further our understanding of the thermal rectification phenomenon. They also show the importance of system asymmetry, emissivity disparities, environmental conditions, and the interplay between convection and radiation. Furthermore, the findings have implications for heat transfer and rectification in asymmetric systems, offering potential applications in areas such as energy harvesting, thermal management, and heat transfer optimization in electronic devices.

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