Study On Micro-climatic Environmental Simulation Model And Digitization For Solar Greenhouse In The Northern Drought Cold Area

Under the support of the project of digitization for agriculture and animal husbandry including of Precise planting and breeding in 2008, mathematical simulation model is developed and test is researched and digital hardware system and software system are designed of micro-climatic environmental for solar greenhouse in the northern drought cold area in winter. The main research contents and conclusions are as below:(1)Mathematical simulation models of lighting and thermal and humidity environment were developed with the purpose of simulation inside shortwave solar radiation, air temperature or relative humidity and soil temperature or relative humidity according to climate characteristic of the northern drought cold area. The crop photosynthesis and respiration was analyzed in these simulation models. To validate the correctness of the models , an experiment was carried out in a solar greenhouse in Qi Sara , TuMoTe , Baotou, Inner Mongolia in winter. The results showed that every simulated data is well consistent with the measured data, and the related coefficient was more than 0.85 and the average relative error was less than 10%.(2)Mathematical simulation model of thermal environment in solar greenhouse includes heat transfer coefficient of convection—α_{a - A}, heat transfer coefficient of longware radiation—βandβ1 and volume of leakage ventilation—φ_leak. In the process of test, three parameters influenced severely the accuracy of model simulation results. After repeated adjustment and test, the value of three parameters was asured.(3)Based on the principle of mass balance, a dynamic simulation model of CO₂ concentration of solar greenhouse was developed in the northern drought cold area. The influenced factors correlative with CO₂ concentration changing such as crop photosynthesis and respiration, soil respiration, CO₂ enrichment and natural or winded of closed situation ventilation were included in the model. To validate the correctness of the model, an experiment was carried out in consecutive days of different weather conditions during winter. The results showed that the simulated data of inside CO₂ concentration is well consistent with the measured data under the condition of sunny or cloudy day, and the related coefficient was more than 0.88 and the average relative error was less than 10%.(4)Mathematical simulation models of lighting , thermal, humidity and CO₂ environment applicable for the solar greenhouse in the northern drought cold area were integrated to be a whole simulation model for the inside environment of solar greenhouse. Inside shortwave solar radiation, air temperature or relative humidity, soil temperature or relative humidity and CO₂ concentration can be simulated as the same time according to daily weather forecast. Through experiments in winter, the results showed that the every simulated data is well consistent with the measured data, and the related coefficient was more than 0.8 and the average relative error was less than 20%. This means the model is applicable for the solar greenhouse in the northern drought cold area in winter.(5)Digital hardware system and software system are designed of micro-climatic environmental for solar greenhouse in the northern drought cold area in winter. The hardware system is designed to complete the environmental factors of solar greenhouse can be detected, converted to electronic signal and transmit information to computer. And the software system is designed to complete basic function such as display, storage and remote transmission on LAN. The forecasting and warning function is designed in the software system basis on the environmental whole simulation model of solar greenhouse.