CFD and experimental analysis of greenhouse climate and plant comfort in mediterranean regions: impact of crop presence and time variations

This study investigates indoor climate dynamics within a large-scale soilless greenhouse in Manouba, northern Tunisia, examining the effects of daily environmental variations. By combining experimental and numerical methods, it analyzes how factors such as glazing, ventilation, crop type, and concrete surfaces influence indoor climate conditions. The study validated a numerical model’s accuracy, particularly for temperature profiles, by comparing its outputs with experimental data. To ensure reliability, the model underwent rigorous testing, including grid independence analysis, incorporation of turbulence and radiation models, and optimization to reflect external conditions accurately. Simulations were run with and without crops, showing that the presence of crops raised temperatures by approximately 1 K for lettuce and 2.2 K for tomato, emphasizing the importance of crop optical properties and transpiration on temperature distribution and ventilation. Temperature patterns within the greenhouse varied, with a 1.2% drop in the center between 13 h and 16 h and a 2.4% increase from 9 h to 13 h. Ground-level temperatures were the highest, largely due to solar radiation. The study established a strong correlation to predict indoor temperature changes in response to external factors, accounting for conditions with and without crops. Additionally, the research addresses thermal comfort indicators like vapor pressure deficit (VPD), offering insights into optimal climate management across different crop scenarios. The findings provide valuable guidance for greenhouse engineers on temperature distribution, suggesting effective sensor placement, monitoring techniques, and control strategies to improve greenhouse performance and crop yield.