EFFECTS OF DIFFERENT VENTILATION SPEEDS ON THE THERMAL ENVIRONMENT OF SOLAR GREENHOUSES

The solar greenhouse is the main agricultural facility in northern China, providing a suitable environment for cultivating vegetables and flowers during the winter season. However, during the months of March and April, adjustments to the indoor temperature in northern Chinese solar greenhouses are necessary through the manipulation of upper and lower air vents. To investigate the impact of varying ventilation speeds on the thermal conditions within a solar greenhouse, Computational Fluid Dynamics (CFD) simulations were employed. The study assessed four different ventilation speeds on the air, soil, and wall temperatures within the greenhouse, assuming the absence of crops and disregarding humidity levels. The results showed that a wind speed of 0.5 m/s effectively reduced air temperature but had little effect on soil and wall temperatures; at wind speeds of 1.0 m/s and 1.5 m/s, the differences in air, soil, and wall temperatures inside the greenhouse were small. Considering economic benefits and crop growth conditions comprehensively, a wind speed of 1.0 m/s was identified as the optimal choice. This study provides data support and a theoretical basis for ventilation design in solar greenhouses.