Evaluation For Physical Model Of Environmental Factors In Energy-Saving Solar Greenhouse

Energy-saving sunlight greenhouse is the main force of current agricultural production in our country, and it plays a very important role in the anti-seasonal vegetable production, with a good prospect. In this paper, a concrete research work is carried out towards the environmental factors inside the energy-saving sunlight greenhouse, and a model is made to estimate the yielding ability of the greenhouse, and it can also evaluate the performance of the control strategy towards the greenhouse.The temperature, sunlight, concentration of CO2 and humidity are main factors for the growth of the plants inside the greenhouse. On the basis of two experiments, four physical models are made for each factor, and an analysis is taken of to find out the relationship among the factors. Having considered the geographical site and local climate of the experimental place, an appropriate control strategy is established for one type of plants, for example, tomato. With the physical models mentioned before, the result of the control strategy can be simulated, and also the effect can be estimated.Through the simulation, a conclusion of the open-close control strategy for the tomato greenhouse in winter in Xuzhou zone can be drawn as follows: the open time is mainly determined by the outside air temperature: if the outside air temperature is over 2℃, the greenhouse can be opened immediately; if it's less than 2℃ but over -3℃, then the greenhouse can be opened after the illumination is over 35000Lx; if it's less than -3℃, then the greenhouse can only be opened as the illumination is over 60000Lx. The close time is mostly decided by the outside illumination: if the outside illumination is less than 20000Lx, and the air temperature is less than 10℃, then the greenhouse should be closed at once, or it can remain opening for a period of time; if the outside illumination is less than 10000Lx, then the greenhouse should be closed promptly. In addition, the CO2 enrichment is commonly arranged at 9:00-10:30, and the ventilation is carried out at 11:00-14:30.Using the physical model to validate the hereinbefore strategy, and with consultingthe experimental datum, we can draw such a conclusion: the strategy for the tomato greenhouse can provide tomato with an appropriate light circumstance, a satisfying temperature in daytime, a sustaining high CO2 concentration in the morning when the photosynthesis is relatively concentrated, and a not very satisfied humidity condition. After being validated with experiments, it can be said as a whole that the control strategy achieves the expected purpose at last, and it can provide a good environment for the growth of tomato in greenhouse.