Mathematical Modeling And Dynamic Simulating Of Greenhouse Microclimate

The latter-day development of greenhouse plantation has been put forward newtasks for greenhouse research. However, how to reduce energy consuming andimprove efficiency maximally is always the all-important problem confronted by thegreenhouse plantation. Based on the mass and energy balance, by means ofmathematical model and the basic theory of heat transfer and thermo-dynamics, theresearch of greenhouse microclimate aims at relating influence genes with theenvironmental parameters of greenhouse and studying the influence of all kinds offactors on greenhouse microclimate synthetically, accordingly, provides theoreticalguidance for greenhouse design. Firstly, according to the research development of each period, this papersummarized the history and current status of greenhouse microclimate research.Furthermore, made use of the environmental genes such as illumination, temperature,humidity and so forth, the greenhouse micro-climate was evaluated synthetically. As we know, solar radiation is the optical and energy base of greenhousemicro-climate. This paper introduced the correlative theory of solar energy using intothe distribution research of radiation in and out of the greenhouse, and presented thecomputational way of solar radiation including the separation of direct and diffuseradiations. The theoretical foundation of greenhouse microclimate modeling was analyzedsystemically on the premise of reasonable assumption. And combining the formerresearch productions, the interrelated energy flow and parameter relations ingreenhouse were described one by one. Still moreover, the recommendatory appliednumeration of which in engineering was presented. Aiming at the localization of the way dealing with the complicated surface informer research, this paper tried to bring forward the simplified model of radiationview factor in greenhouse and computed the radiation exchange among thegreenhouse surfaces concluding the canopy making use of the tradition radiationtheory. On the base of typically reference computation in each country and heat transfertheory, taking example for full-ray greenhouse, we built the steady and unsteadymodel from the point of static state and dynamic state. Transmission and heat preservation performances were the important guidelinesdescribing the synthetically level of greenhouse. Making use of the dynamic model,this paper simulated the greenhouse microclimate continuously, studied the solarradiation transmission and heat load during nights of glass greenhouse quantificationally, and comparatively analyzed the influence of several typical conditions on heatsupply load, which provided the theoretical guidelines for the day-lighting and heatsupply designs. In addition, used of the coupling model of heat and humidity andone-dimension heat transfer model, the energy and mass transfers and the temperaturedistribution were simulated dynamically and researched experimentally, as a result,the typically periodic rule of heat store was found. In conclusion, by comparing the theoretical research results with theexperimental data, the reliability of the model was validated.