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• Modeling of a unique solar cooker having L-shaped absorber and internal reflector. • Novel design rendered a significant performance improvement at low incidence angle. • CFD simulations to find free convection heat transfer inside unique cooking cavity. • Parametric analysis to study the effect of key factors on cooker's performance. A unique design of a double glazed box-type solar oven with flat foldable external reflectors at the top and front and an internal reflector beneath the L-shaped absorber plate is numerically and parametrically studied. The maximum temperatures attained in the absorber cavity of the oven are observed to be in the range of 100–135 °C. A numerical model is formulated to solve the overall energy balance on the absorber plate of the proposed solar oven by incorporating the effects of the top, front, and bottom reflectors for a given set of input parameters. CFD simulations are utilized to predict the unknown buoyancy driven convective heat transfer coefficient from the L-shaped absorber plate to the surrounding glass cover forming an enclosure. Modeling results are found to be in good agreement with the experimental results which leads to the parametric study of the solar oven. The effects of various design parameters on the oven's performance such as spacing between glazings, influence of the vertical component of the absorber plate and internal reflector, glazing thickness number of glazings and the effect of absorber plate coatings are also discussed. [ABSTRACT FROM AUTHOR]

This paper introduces a novel design of a double glazed box type solar cooker having an L-shaped absorber plate with one internal (bottom) and two external plane reflectors. A series of experiments were performed to access the cooker's thermal performance at the location of Taxila (33.74°N, 72.80°E) in Pakistan during the year 2017. The cooker's performance is evaluated in terms of maximum absorber plate temperature and other thermal performance indicators like first and second figures of merits (F1 and F2), parameter index, energy efficiency, and utilizable efficiency. The experimentally obtained values of all the performance indicators are found to be in the recommended ranges specified in the literature. An increment of about 30% in the absorber plate temperature is estimated for the case of the proposed L-shaped absorber plate along with an internal (bottom) reflector as compared to the case of no internal reflector and a conventional horizontal absorber plate. The first figure of merit of the proposed cooker is estimated to be 0.12, thus classifying it in grade A category. Furthermore, the solar cooker is manufactured at a nominal cost of ∼130 USD, making it a competitive product in the market. [ABSTRACT FROM AUTHOR]