Computational modeling and assessment of novel irradiation-controlled geothermally cooled greenhouse in hot arid climates

Conventional greenhouses, with their high transmittance for solar irradiation and conductive nature, result in significant heat transfer to the interior. While this feature is desirable in cold regions, it poses a challenge in hot arid areas, causing excessive heat and an unsuitable rise in the internal greenhouse temperature for crop growth. Conventional passive cooling methods prove insufficient, in addition, solely active cooling is both energy-intensive and environmentally harmful, making it economically unfeasible under certain conditions. In this research, a novel greenhouse design optimized for hot arid regions is proposed, incorporating several cost-effective and innovative techniques: (1) a fully sunken greenhouse, (2) a fully shaded roof with openings for diffuser lenses, (3) a thermally insulated roof, and (4) a closed-loop horizontal earth-to-air heat exchanger. Computational modeling involved developing a ray-tracing model and a heat transfer model for the proposed greenhouse. The results demonstrate that the proposed greenhouse achieves sufficient and well-distributed solar irradiation for plant growth. Also, it shows a remarkable (85.6%) reduction in cooling load during the hot season (April to October) compared to a conventional greenhouse. Furthermore, economic assessment results indicate a 67.8% reduction in the lifetime cost of greenhouse cooling compared to a conventional design.