A greenhouse climate model for control design

In this paper, based on energy and mass balance, a greenhouse climate dynamic model with three state variables and six control variables is developed to predict the temperature, humidity and CO₂ concentration of the indoor environment for control design. To keep the model as simple as possible, algebraic fitting technique and time sequence functions are used to calculate some variables such as the temperature of cover and the temperature of floor. Meantime, some modules such as photosynthesis model and ventilation model are also simplified. In contrast to some complete models, the number of state variables is reduced, and the simulation results indicate that the reduced model has good simulation performance and is sufficient to be used to greenhouse climate design.