Beyond the combustion chamber: Heat transfer and its impact on micro-thermophotovoltaic systems performance

Conversion of thermal radiation into electrical current in thermophotovoltaic devices is directly influ-enced by the heat transfer, since the cell efficiency depends on the temperature. For micro-scale devices, heat management is yet more important due to the proximity between the components. A detailed study in these systems needs to considers the presence of wavelength-selective optical filters, used to reflect undesired radiation. In this study, we propose a model where the dependence of the physical parameter with the radiation wavelength is taken into account through a discretization of the radiation spectrum into several bands and estimation of average values. By coupling this procedure with a computational fluid dynamics solver, the cell efficiency as a function of geometrical and operational parameters can be estimated. The results indicate the existence of an optimal emitter/cell distance, depending on the emitter temperature and the heat transfer coefficient between the cell and the external medium. A secondary cooling mechanism, the air flow between the emitter and the filter, can also help to reduce the cell temperature. While the emitter average temperature has a strong impact on the cell efficiency, the temperature distribution in the emitter surface has no significant influence, allowing the use of average values. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The conversion of thermal radiation into electrical current in thermophotovoltaic devices is influenced by heat transfer, especially for micro-scale devices where heat management is crucial. A model considering wavelength-selective optical filters has been proposed to estimate cell efficiency by discretizing the radiation spectrum into bands and using average values. Results show the importance of optimal emitter/cell distance and secondary cooling mechanisms in improving cell efficiency.