Numerical analysis of a hybrid tubular and cavity air receiver for solar thermal applications

Sasidharan, S and Dutta, P (2020) Numerical analysis of a hybrid tubular and cavity air receiver for solar thermal applications. In: International Journal of Numerical Methods for Heat and Fluid Flow . (In Press)

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Abstract

Purpose: This paper aims to deal with characterisation of the thermal performance of a hybrid tubular and cavity solar thermal receiver. Design/methodology/approach: The coupled optical-flow-thermal analysis is carried out on the proposed receiver design. Modelling is performed in two and three dimensions for estimating heat loss by natural convection for an upward-facing cavity. Heat loss obtained in two dimensions by solving coupled continuity, momentum and energy equation inside the cavity domain is compared with the loss obtained using an established Nusselt number correlation for realistic receiver performance prediction. Findings: It is found that radiation emission from a heated cavity wall to the ambient is the dominant mode of heat loss from the receiver. The findings recommend that fluid flow path must be designed adjacent to the surface exposed to irradiation of concentrated flux to limit conduction heat loss. Research limitations/implications: On-sun experimental tests need to be performed to validate the numerical study. Practical implications: Numerical analysis of receivers provides guidelines for effective and efficient solar thermal receiver design. Social implications: Pressurised air receivers designed from this method can be integrated with Brayton cycles using air or supercritical carbon-dioxide to run a turbine generating electricity using a solar heat source. Originality/value: The present paper proposes a novel method for coupling the flux map from ray-tracing analysis and using it as a heat flux boundary condition for performing coupled flow and heat transfer analysis. This is achieved using affine transformation implemented using extrusion coupling tool from COMSOL Multiphysics software package. Cavity surface natural convection heat transfer coefficient is obtained locally based on the surface temperature distribution. © 2020, Emerald Publishing Limited.

Item Type:	Journal Article
Publication:	International Journal of Numerical Methods for Heat and Fluid Flow
Publisher:	Emerald Group Holdings Ltd.
Additional Information:	Copyright to this article belongs to Emerald Group Holdings Ltd.
Keywords:	Brayton cycle; Carbon dioxide; Flow of fluids; Heat flux; Heat losses; Natural convection; Numerical analysis; Optical flows; Solar heating; Supercritical fluid extraction; Thermoanalysis, Affine transformations; Coupled flow and heat transfers; Design/methodology/approach; Flux boundary conditions; Nusselt number correlation; Solar thermal applications; Supercritical carbon dioxides; Surface temperature distribution, Heat transfer performance
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	13 Jan 2021 06:42
Last Modified:	13 Jan 2021 06:42
URI:	http://eprints.iisc.ac.in/id/eprint/67630

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