| The protected agriculture, because have characteristic of intensive technology and workforce with high investment, play an important role in rural of our country economic development and the international competitiveness raising. Especially in southern China economy developed with fewer land, more people, the development modern greenhouse cannot merely strengthen the international competition, and will solve peasant's employment of southern area and raise income.This paper on the basis of the effective experiment, simulates and analyses the microclimate under different weather conditions of the subtropical modern greenhouse, and predicts energy consumption. This offered theoretical foundation to greenhouse selection, greenhouse design, the greenhouse controlled etc. The main contents of this paper include follows:(1) The measurement of microclimate parameters is studied. According to the characteristics of weather conditions, suitable sensors and data gather system are selected and used to measure greenhouse microclimate automatically.(2) The plant transpiration and its influence on the microclimate are studied.(3) Set up the modern greenhouse simulation model for southern China weather conditions. On the basis of what forefathers studied, using the greenhouse heat and quality discharge mechanism to analyze heat balance of greenhouse cover, inside air, plant surface and soil surface, and analyze quality balance of greenhouse inside air, outside air and plant, it proposes greenhouse quality and heat balanced models and sets up greenhouse the computer dynamic simulation systems, and analyze model parameters which effect to greenhouse microclimate. Through these, the sensitiveness of parameters to outside condition and greenhouse structure also analyzes.(4) Use BP nerve network models analyze greenhouse microclimate under plum rains season. Fully utilize the non-linear characteristic of the nerve model and solve multi-parameters, it sets up the simulation model of the nerve network, analyses weight and threshold value in the network, observing the influence value of everyrelevant factor, as the useful supplement of physical model.(5) Prediction the basic energy consumption of greenhouse is studied. On the basis of heat balanced, using plant grow condition; it calculates energy short under winter and heat accumulated under summer.Through above studies main conclusion are listed as follows:(1) In summer or plum rains season, greenhouse inside temperature changes in-phase with outside temperature and behind to outside solar radiation. Wind speed shows negative correlation with inside temperature, higher wind speed is helpful to reduce temperature inside greenhouse.In winter, outside solar radiation, temperature are lower than summer, higher inside temperature is mainly controlled by heat pipe temperature at night, Heat equipment is the main energy source, inside temperature is mainly affected by heat pipe temperature and also outside temperature, outside solar radiation at daytime, A day temperature appears higher at daytime and lower at night which called DIF mode.(2) According to simulation result of each surface temperature in the greenhouse, simulation result of summer is higher than plum rains season and winter, but all has higher precision and better stability, can meet the demands of practical application.(3) Inside relative humidity affect by relative humidity outside mainly, increase with outside humidity in summer, and shows negative correlation with outside wind speed at the same time, namely higher outside wind speed can reduce the humidity inside greenhouse. In winter inside relative humidity affect by the transpiration rate mainly, and increase with the transpiration rate, and shows negative correlation with heat pipe temperature, higher heat pipe temperature is helpful to improve inside temperature, thus causes the reducing of the humidity inside greenhouse. Plum rains season inside relative humidity affect by relative humidity outside strongest... |
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