Modelling Greenhouse Thermal Environment in North China Based on Simulink

摘要

This paper deals with the problem of modelling greenhouse indoor thermal environment in China. In order to achieve this goal, six main factors were taken into account in describing the greenhouse heat exchange with the outside, including solar radiation, artificial heating, long wave radiation, convection, ventilation and crop transpiration. According to the thermal balance principle of greenhouse, by quantizing vent opening, based on a design idea of Simulink platform, a non-linear differential mathematical model for simulating the greenhouse indoor air temperature was built. An experiment was taken to testify the validity of the simulation model in a Venlo type greenhouse in North China during spring. By using two groups of typical measured data in different weather conditions, the simulated value agreed well with the measured data. The results show that the standard errors in sunny and cloudy days are 0.6738℃ and 0.3051 ℃ respectively, as well as the index of simulation effectiveness is 81.17% and 82.12%. The results provide a basis of a model for the environmental regulation research on North China greenhouse.