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This study presents an investigation into forced convection within laminar fluid flow through a configuration consisting of two heated cubic obstacles with circular perforations, arranged in a staggered pattern on a horizontal plate. The research addresses the critical challenge of enhancing heat transfer in such configurations by examining the influence of variations in streamwise distance (L) and spanwise distance (m) on thermal performance. Employing the finite-volume method, simulations were conducted across a range of parameters: L from 1 to 2 times the obstacle height (H), m from 1/2 to 2 times H, Reynolds numbers (Re) between 102 and 3 × 102, and perforation diameter ratios (D/H) of 0.42 and 0.88. The findings reveal that the Nusselt number (Nu) exhibits significant variation with changes in L/H for solid obstacles, while this effect diminishes for perforated obstacles, particularly at a D/H ratio of 0.88. For the first obstacle, optimal heat transfer is achieved with a streamwise distance equal to H for solid obstacles, whereas no notable differences are observed between the arrangements of perforated models. Notably, perforated obstacles with the maximum D/H ratio exhibit a Nu increase of up to 30% compared to solid obstacles. For the second obstacle, the optimal configuration across all types involves a streamwise distance of H and a spanwise distance of 2H, leading to a 37.4% increase in Nu for large-diameter perforated obstacles compared to solid ones. Overall, the staggered arrangement of perforated obstacles outperforms the tandem arrangement, enhancing heat transfer by up to 43.52% for the first obstacle, 109% for the second obstacle, and 48% for the entire system. This study introduces novel insights into the impact of perforation and obstacle arrangement on heat transfer, demonstrating that staggered arrangements and larger perforation diameters significantly enhance heat transfer compared to solid obstacles, thereby advancing the understanding of convective heat transfer in such setups. [ABSTRACT FROM AUTHOR]

Air plate solar collectors provide a sustainable and efficient solution for building heating. The absorber plate collects solar radiation and converts it into heat. Atmospheric air is then circulated through the collector plate with perforated baffles by forced convection. The heated air is then directed through ducts into the building's heating system. By significantly reducing reliance on fossil fuels for building heating, these collectors contribute to a lower life-cycle carbon footprint for buildings compared to conventional heating systems. While flat-plate solar collectors are widely used for renewable energy generation, their efficiency is frequently limited by the airflow path and the heat transfer efficiency within the collector. This study aims to quantify the impact of longitudinal, transverse, and perforated baffles with different hole diameters on the heat transfer characteristics and to identify the optimal design for maximizing thermal efficiency. This study also aims to integrate solar air collector in a conventional building and help reduce the overall energy demand of buildings and their associated carbon emissions. A three-dimensional numerical investigation was carried out on a flat-plate solar collector equipped with perforated transverse baffles with varying hole diameter and thickness. The results from the study predicted that perforated baffles with two holes with a diameter of 15 mm provided a maximum Nu of 79.56 and a pressure drop of 459 Pa for a Re of 8500. [ABSTRACT FROM AUTHOR]

Saving energy and protecting the environment are the cornerstones of the modern concept of energy consumption. Following the Algerian program on renewable energies and energy consumption, dictated by Algeria's new energy transition policy, 40% of electricity production should come from renewable energies by the year 2030. The present article accompanies this policy and makes an attempt to improve the energy efficiency. This work presents a comparative experimental study of two models of flat plate air solar collectors, namely a solar collector with black mini solar concentrators (BMSC) and another model, similar to the first one, with the same geometry and dimensions, and supplied with mini solar concentrators and mirrors (MSCMR) instead of black mini solar concentrators. A comparison of the temperature profiles for these two models of solar collectors is performed in this work, in the two cases of free convection and forced convection. Comments on this innovative design are presented and the results obtained are found encouraging. [ABSTRACT FROM AUTHOR]