Research Of Temperature And Humidity Forecasting Model Of Solar Greenhouse

In this paper, a temperature and humidity forecasting model was built based on the large delay character of temperature and humidity in greenhouse using the heat exchange principle lor solar greenhouse the unique style agricultural facility of China. In the forecasting model, the basic-physical process such as thermal radiation, convection, solar radiation, plant transpiration, evaporation from ground and natural ventilation etc. were described and the latent heat caused by plant transpiration, evaporation from ground and natural ventilation was also included. By using the environmental parameter (inside temperature and humidity, outside temperature and humidity. ground temperature, solar radiation of inside and outside the greenhouse, outdoor wind speed and direction, etc.) which can be easy acquired by sensor, greenhouse structure, plant parameter etc., the model can predict the temperature and humidity inside the greenhouse, which built a foundation for the fore feed and back feed control of solar greenhouse.A program was developed with Visual Basic 6.0 to compute the forecasting model, which can be used to predict the variation of temperature and humidity inside the greenhouse. By comparison between the predicted and measured value, the average and maximum error between simulated and measured air temperature are separately ±0.5 ℃ and ± 1.7℃, and those of relative humidity are separately +5% and ±13%, both of which are within acceptable ranges.