Research Of The Air Temperature Time-series Model And Evaluation Open Greenhouse In Summer

Time-series modeling of the air temperature and quantitative analysis of the greenhouse evaluation system of the Open Air greenhouse is key part to achieve intelligent control of the Open Air greenhouse in summer. And it can help reduce greenhouse energy consumption and increase greenhouse production efficiency. The research on the Open Air greenhouse was very little in China, and we have not found the forecast modeling of the air temperature in the Open Air greenhouse. Thereby, researches of the time-series model of the Open Air greenhouse and evaluation of the Open Air greenhouse have theoretical significance and practical value.In this paper, regarding the problems of time-series modeling of the air temperature of the Open Air greenhouse and evaluation of the Open air greenhouse, first of all, we analyzed the air temperature and air relative humidity characteristics of the Open Air greenhouse in summer; secondly, we established an air temperature time-series model; finally, we compare venlo-type greenhouse with the Open air greenhouse in order to quantitatively evaluate the natural ventilation cooling and energy saving effect of the Open Air greenhouse in summer. The main studies are as follows.(1) The distributed multi-sensor temperature measurement network based on RS-485 bus was developed in this paper in order to automatic measure the air temperature and air relative humidity of the Open Air greenhouse. The air temperature and relative humidity characteristics of the Open Air greenhouse on horizontal and vertical plane were analyzed on the typical outdoor weather conditions in summer.(2) The air temperature time-series model was developed by introducing the main external environment variables such as external air temperature, greenhouse natural ventilation rate, external solar radiation, and greenhouse air relative humidity. These variables can influence greenhouse internal air temperature and both of them are non-stationary variables. The model was assessed with co-integration methods in order to avoid spurious regression phenomenon. The model was assessed with error correction methods in order to improve the prediction accuracy. At the same time, the time-series model forecasts were compared with measured data to verify the time-series model. The results showed that, the model has a better forecast accuracy and provide feedforward information for automatic control in summer.(3) Based on the above studies, the quantitative evaluation of natural ventilation cooling effect and energy saving effect and environmental features of the Open Air greenhouse was established in this paper. At the same time, by using the venlo-type greenhouse as a reference greenhouse, we analyzed the air temperature and air relative humidity distribution uniformity of the Open Air greenhouse in summer. The results showed that, the Open Air greenhouse has a more uniform air temperature and air relative humidity distribution. On the basis of measuring the natural ventilation rate of the Open Air greenhouse and venlo-type greenhouse, we analyzed the natural ventilation cooling and energy saving effect on the typical outdoor weather conditions in summer. The results showed that, the cooling and energy saving effect of the Open Air greenhouse was better than that of venlo-type greenhouse.In this paper, we quantitatively analyzed the air temperature distribution characteristics and natural ventilation cooling effect and energy saving effect. At the same time, we developed an air temperature time-series model. The research achievements provide data supports and theoretical basis for the temperature intelligent control of the Open Air greenhouse, and also laid a basis for assessment of the cooling effect of the Open Air greenhouse in summer.