Authors

Abstract

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.

Abstract in Chinese

日光温室作为我国重要的农业设施，能够为作物生长提供适宜的环境条件。然而，3 - 4月份日光温室内温度依然较高，这不利于作物的生长。通风是降低温室内温度的有效措施之一。因此，本文以计算流体动力学（CFD）为模拟手段，设置了4种不同风速（0 m/s、0.5 m/s、1.0 m/s、1.5 m/s）的通风条件，探究不同通风速率对温室内空气、土壤和墙体温度的影响。研究结果表明：在9：00-14：00时段，室内空气温度随时间先快速上升，后趋于平缓，再下降；土壤和墙体温度则持续上升，不同风速下其温度差异随时间增大。距离墙体内表面越深、距离地面越高，风速对墙体温度的影响越小。0.5m/s风速可有效降低室内空气温度，但对土壤和墙体温度影响较小。1.0m/s和1.5m/s风速下，室内空气、土壤和墙体温度差异均较小。综合经济效益与作物生长环境等因素，1.0m/s风速为最佳选择。该研究可为日光温室通风设计提供数据支撑和理论依据。