Research On Heat Transference Model Of Multi-span Plastic Greenhouse And Energy Consumption Forecast

With the booming of greenhouse crop farming, Reducing the greenhouse energy consumption, cost saving, raising resources utilization ratio has increasingly become daily the problem in the public concern. Greenhouse heat transfer mechanism research is the base of analyzing the greenhouse running energy consumption and improving the greenhouse production efficiency. Temperature is one of the most important factors in the greenhouse micro-environment.This thesis took multi-span plastic greenhouse as object of study. Under reasonable hypothesis premise, greenhouse heat transfer model in steady state was established. Simultaneously unified the predecessor's results, greenhouse interior environment was divided into cover layer, internal air layer, canopy and the soil level.and has carried on the heat transfer analysis and the mathematical linguistics description separately, the nonlinear simultaneous equation was set up and was solved with the help of MATLAB mathematic software. We hope that the model can carry on the simulation through outdoor climatic conditions to greenhouse internal temperature environment.Experiment was carried out in the greenhouse of College of Engeering and Technology,Huazhong Agricultural Univercity. We has established measuring points arrangement and the data acquisition in the winter. Taken the outdoor data and the greenhouse design parameter as the input parameters, we soleved this heat transfer model.Compared the actual temperature to the simulation temperature, the result indicated: This temperature model can accurately forecast indoor temperature change, and because of the essential suppositions and the simplification in the modelling process,some error happened.Based on the greenhouse heat transfer model, computed the greenhouse winter warming energy consumption, obtained design outside temperature was -8℃, design inside temperature during day time was 28℃, night inside design temperature was 20℃, and energy consumption quantity is 142W/m2.In addition, forecast the greenhouse running energy consumption with degree-hour method, determined the greenhouse winter heating load is 58.5Kg/m2 in Wuhan. Finally, put forward the greenhouse energy conservation management proposal to enhance the production efficiency, raising resources utilization ratio and product quality of facility agriculture.