Far-Field Radiative Thermal Rectification Based on Asymmetric Emissivity
Ng, Ryan C. (Institut Català de Nanociència i Nanotecnologia)
Sachat, Alexandros el (National Center for Scientific Research "Demokritos")
Jaramillo Fernández, Juliana (Universitat de Barcelona. Departament d'Enginyeria Electrònica i Biomèdica)
Sotomayor Torres, Clivia M. (Institut Català de Nanociència i Nanotecnologia)
Chávez Ángel, Emigdio (Institut Català de Nanociència i Nanotecnologia)

Data:	2024
Resum:	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.
Ajuts:	Agencia Estatal de Investigación SEV-2017-0706 European Commission 897148 European Commission 101029727 Agencia Estatal de Investigación 2021/SGR-0100
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Far field thermal radiation ; Thermal rectifier ; Radiative cooling ; Asymmetric thermal radiation ; Thermal management
Publicat a:	ACS Applied Optical Materials, Vol. 2, Issue 6 (June 2024) , p. 973-979, ISSN 2771-9855

DOI: 10.1021/acsaom.3c00235
PMID: 38962567

7 p, 2.4 MB

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