Optimizing Energy Efficiency and Light Transmission in Greenhouses Using Rotating Low-Emissivity-Coated Envelopes

Growing demand for sustainable agricultural solutions has driven innovations in greenhouse design, particularly in urban areas. This study evaluated the relationship between transparent envelope thermal properties and greenhouse energy loads through regression analysis using DesignBuilder simulations. The thermal performance of the envelope was designated as independent variables to quantify its impact on heating and cooling loads. Based on this analysis, a rotatable low-emissivity (low-E) coating envelope system optimized for temperate climate zones was proposed. This system allows seasonal adjustment of coating orientation to enhance energy efficiency. Compared to traditional materials, this approach achieved up to 16% energy savings without compromising visible light transmittance, essential for crop growth. While double-glazed low-E glass demonstrated the highest energy reduction (22%), it reduced visible light transmittance by 20%, potentially affecting crop productivity. In contrast, the proposed system maintained high visible light transmittance while achieving significant energy efficiency, balancing energy performance and light environment requirements. Additionally, integrating the greenhouse with building structures resulted in a 31.91% reduction in building energy consumption through improved insulation. These findings highlight the potential of adaptable greenhouse envelopes to improve energy performance and support urban sustainability.