Investigation of Heat Transfer and System Efficiency in a Solar Electric Greenhouse Dryer Using Dimensionless Analysis

This study investigates the integration of an electric heater and a greenhouse dryer, enhanced by thermal storage technology, to improve drying efficiency. By applying heat storage materials to the dryer bed, the system's thermal performance is significantly enhanced. The research focuses on evaluating the thermal characteristics of the modified dryer under no-load conditions, conducted from June 2024 to August 2024 during peak sunshine hours at the PVT Lab, National Institute of Technology Silchar (24.75°N, 92.79°E), Assam, India. Experiments were performed between the 15th and 17th of each month. The dryer incorporates an opaque north wall, contributing to its optimized design. Results indicate that the modified solar electric greenhouse dryer outperforms conventional solar dryers, with significant improvements in thermal efficiency. Key dimensionless parameters, including the Nusselt, Grashof, Prandtl, and Rayleigh numbers, were computed numerically based on experimental data to assess the system's heat transfer dynamics. Additionally, the system's electrical efficiency was evaluated.