Ground duct ventilation in greenhouses

Abstract

A greenhouse climate control system is simulated in MATLAB and Simulink. The model calculates for every 20 minutes the temperatures and energy consumption over a whole year. Ground ducts are used in order to save energy which is stored in the ground when there is an excess of heat during the day. This energy is used when the temperature is not high enough, generally in the early morning. Additionally, the ground ducts reduce the usage of windows, due to better dehumidification and cooling. When the windows are closed, the produced CO2 will be kept inside. Moreover, the circulation within the greenhouse improves. These combined effects not only accelerate the growing of the plants but also improve their health. The calculation model includes water condensation near the roof, walls and inside the ground ducts and also evaporation via the plants. In order to reduce the complexity of the simulation, the system is partially limited to a 1‐dimensional system. After a mathematical validation of the model, the simulation results are compared with data of measurements in a greenhouse with ground ducts. Based on this validation the most optimal configuration of ground‐ducts is predicted.