The Influence of Natural Ventilation to the Thermal and Moisture Environment in a Passive Greenhouse

Abstract

The temperature and humidity profiles in spatial and temporal field inside the greenhouse are coupled to outside climates. Took a typical soil-walled passive greenhouse located in Jinan, Shandong, China as an example, an unsteady tri-dimensional numerical simulation was applied to solve the temperature and humidity profiles under natural ventilation conditions inside the greenhouse, based on the CFD program. The measurement was carried out to validate the CFD model, the results showed that the special temperature and humidity gradient were obvious inside the greenhouse, a homogeneous temperature and humidity field was obtained at crop level. The simulation results agree well with test values about the temperature and humidity inside the greenhouse with fitting degree of 99.8% and 99.7%, respectively. With high reliability, the model can be used as the basis to predict and control the environment inside the greenhouse. Greenhouse with natural ventilation under different wind conditions was simulated on a typical sunny day to predict the distribution of air flow, temperature and humidity field. By analyzing, some useful conclusions which can provide certain basis about the influence of natural ventilation on the thermal and moisture environment are deduced.