scholarly journals Design and Heat-dissipation Characteristics of a Novel Spectrally Selective Thermal-radiation Material

2021 ◽  
Vol 14 (0) ◽  
pp. E20-006-1-E20-006-4
Author(s):  
Maki Ito ◽  
Takashi Ando ◽  
Naoki Maruyama ◽  
Takanobu Kobayashi ◽  
Yoshitaka Takezawa
Keyword(s):  
Thermal Radiation ◽  
Heat Dissipation ◽  
Spectrally Selective ◽  
Radiation Material

scholarly journals The Kirchhoff Transformation for Convective-radiative Thermal Problemsin Fins

2021 ◽  
Vol 15 ◽  
pp. 12-21
Author(s):  
Jonatas Motta Quirino ◽  
Eduardo Dias Correa ◽  
Rodolfo do Lago Sobral
Keyword(s):  
Thermal Conductivity ◽  
Boundary Conditions ◽  
Thermal Radiation ◽  
Heat Dissipation ◽  
Variable Thermal Conductivity ◽  
Dirichlet Boundary Conditions ◽  
Heat Transfer Analysis ◽  
Temperature Function ◽  
Kirchhoff Transformation ◽  
Comparison Of The Results

- The present work describes the thermal profile of a single dissipation fin, where their surfaces reject heat to the environment. The problem happens in steady state, which is, all the analysis occurs after the thermal distribution reach heat balance considering that the fin dissipates heat by conduction, convection and thermal radiation. Neumann and Dirichlet boundary conditions are established, characterizing that heat dissipation occurs only on the fin faces, in addition to predicting that the ambient temperature is homogeneous. Heat transfer analysis is performed by computational simulations using appropriate numerical methods. The most of solutions in the literature consider some simplifications as constant thermal conductivity and linear boundary conditions, this work addresses this subject. The method applied is the Kirchhoff Transformation, that uses the thermal conductivity variation to define the temperatures values, once the thermal conductivity variate as a temperature function. For the real situation approximation, this work appropriated the silicon as the fin material to consider the temperature function at each point, which makes the equation that governs the non-linear problem. Finally, the comparison of the results obtained with typical results proves that the assumptions of variable thermal conductivity and heat dissipation by thermal radiation are crucial to obtain results that are closer to reality.

scholarly journals Spectrally selective thermal radiation based on intersubband transitions and photonic crystals

2009 ◽  
Vol 17 (21) ◽  
pp. 19190 ◽  
Author(s):  
T. Asano ◽  
K. Mochizuki ◽  
M. Yamaguchi ◽  
M. Chaminda ◽  
S. Noda
Keyword(s):  
Photonic Crystals ◽  
Thermal Radiation ◽  
Intersubband Transitions ◽  
Spectrally Selective

Spectral Control of Thermal Radiation Using Metal-Dielectric Multilayers for High-Temperature Usage Over 1000°C

2016 ◽  
Author(s):  
Makoto Shimizu ◽  
Asaka Kohiyama ◽  
Fumitada Iguchi ◽  
Hiroo Yugami
Keyword(s):  
Thermal Radiation ◽  
High Efficiency ◽  
Radiation Spectrum ◽  
Layer Structure ◽  
Short Wavelength Range ◽  
Coating Technology ◽  
Selective Coating ◽  
Spectrally Selective ◽  
Spectral Control ◽  
Layer Coating

The spectrally selective coating technology which can be applicable for solar-thermophotovoltaic (solar-TPV) generation systems is described in this paper. In solar-TPV system, the spectrally selective absorber plays a key role to obtain high-efficiency. The technologies of controlling thermal radiation spectrum at temperature over 1000°C, however, have not been established yet. We focus on metal-dielectric multi-layer coating. This selective coating shows enormously high absorptance at short wavelength range and sharp cutoff property. Thermal stability test confirms that this multi-layer structure can be one of the candidates for the selective coatings for solar-TPV systems.

High-Efficiency Thermophotovoltaic System by Quasi-Monochromatic Thermal Radiation

2014 ◽  
Author(s):  
Asaka Kohiyama ◽  
Makoto Shimizu ◽  
Hiroaki Kobayashi ◽  
Fumitada Iguchi ◽  
Hiroo Yugami
Keyword(s):  
Thermal Radiation ◽  
Conversion Efficiency ◽  
Spectral Response ◽  
Detailed Balance ◽  
Total Efficiency ◽  
Emitter Temperature ◽  
Selective Emitter ◽  
Photovoltaic Conversion ◽  
Spectrally Selective ◽  
Photovoltaic Conversion Efficiency

Efficiency of solar-thermophotovoltaic (TPV) systems can be improved by controlling spectral property of thermal radiation to match the photovoltaic (PV) cells spectral response. We developed a spectrally selective emitter which can emit quasi-monochromatic thermal radiation to improve the efficiency of TPV systems. From the evaluation by the detailed-balance model for gallium antimonite (GaSb) TPV cells, the photovoltaic conversion efficiency over 50 % is achievable in the case of the emitter temperature over 1800K and emitter Q-value over 15. The numerical simulation based on Rigorous-Coupled Wave Analysis revealed that the quasi-monochromatic thermal radiation can be obtained by closed-end microcavity structure. A solar-TPV system equipped with a solar-simulator is fabricated to evaluate the effect of spectrally selective emitter. By using GaSb TPV cells and spectrally selective emitter based on dielectric layer coating, photovoltaic conversion efficiency of 26% and total efficiency of 7.7% are obtained at emitter temperature of 1654 K under 384 suns.

A metal nanoparticle assembly with broadband absorption and suppressed thermal radiation for enhanced solar steam generation

2021 ◽  
Author(s):  
Dawei Ding ◽  
Hu Wu ◽  
Xiaoping He ◽  
Fan Yang ◽  
Chuanbo Gao ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Radiation Loss ◽  
Metal Nanoparticle ◽  
Nanoparticle Assembly ◽  
Steam Generation ◽  
Solar Absorption ◽  
Broadband Absorption ◽  
Nickel Nanoparticle ◽  
Spectrally Selective ◽  
Solar Steam Generation

The efficiency of solar steam generation is boosted by broadband solar absorption and suppressed thermal radiation loss of a nickel-nanoparticle-based spectrally selective absorber.

Al0.97Y0.03PO4 thermal radiation material with enhanced infrared emissivity

2020 ◽  
Vol 46 (2) ◽  
pp. 2010-2015
Author(s):  
Na Li ◽  
Xia Huang ◽  
Da Wang ◽  
Junfeng Wang ◽  
Chang He ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Infrared Emissivity ◽  
Radiation Material

scholarly journals Effect of Surface Microstructure on the Heat Dissipation Performance of Heat Sinks Used in Electronic Devices

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 265
Author(s):  
Yuxin You ◽  
Beibei Zhang ◽  
Sulian Tao ◽  
Zihui Liang ◽  
Biao Tang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Thermal Radiation ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
High Heat ◽  
Heat Sinks ◽  
High Heat Flux ◽  
Thermal Emissivity ◽  
Effect Of Surface

Heat sinks are widely used in electronic devices with high heat flux. The design and build of microstructures on heat sinks has shown effectiveness in improving heat dissipation efficiency. In this paper, four kinds of treatment methods were used to make different microstructures on heat sink surfaces, and thermal radiation coating also applied onto the heat sink surfaces to improve thermal radiation. The surface roughness, thermal emissivity and heat dissipation performance with and without thermal radiation coating of the heat sinks were studied. The result shows that with an increase of surface roughness, the thermal emissivity can increase up to 2.5 times. With thermal radiation coating on a surface with microstructures, the heat dissipation was further improved because the heat conduction at the coating and heat sink interface was enhanced. Therefore, surface treatment can improve the heat dissipation performance of the heat sink significantly by enhancing the thermal convection, radiation and conduction.

Sign in / Sign up

Export Citation Format

Share Document