COMPUTATIONAL ANALYSIS OF THE EFFECT OF AN EXTERNAL BARRIER ON THE VENTILATION AND THERMAL PERFORMANCE OF A GREENHOUSE

The construction of greenhouses in semi-urban areas implies the presence of neighboring buildings that can be an obstacle to natural ventilation, modifying the intensity and direction of air currents. However, they could also function as protective barriers against these currents at off-peak hours. The objective of this work was to analyze the effect of an external physical barrier on the thermal behavior and air currents inside a Gothic type greenhouse for tomato (Solanum lycopersicum L.) production. A 3D steady-state simulation was performed and validated using 15-day experimental temperature data with typical climatic conditions for the month of July 2023. The effect of the 3 m high external barrier was analyzed, which was placed at 5, 10, and 15 m distance from the greenhouse, located in the direction of the prevailing winds, on the fluid dynamic and thermal behavior inside the greenhouse. The results showed differences in the behavior of air currents inside the greenhouse with the presence of the external barrier, which affected the velocity and direction of the air inlet, accentuated by the proximity between the obstacle and the greenhouse. Under the studied conditions, placing the barrier 5 m away represents an advantage when there are low temperatures at dawn, managing to preserve the temperature inside the greenhouse up to 4 °C above the temperatures recorded in the barrier-free scenario or with the barrier 10 and 15 m away. The simulated data at 14:00 h showed differences of less than 0.4 °C between the cases with different barrier distances, so the influence of the barrier at the above-mentioned time is not significant.