| Nowadays, there are about one hundred million people in the northeast of China. They consume more than ten billion kilograms of vegetables every year. But most of vegetables are transported from the south in winter, thus a lot of manpower and money has been wasted. The main reason for the waste is that the use ratio of greenhouse is very low in the northeast. In best structure greenhouse, the difference in temperature is below 25℃if the greenhouses have not heating equipment from December to January. Nevertheless, the temperature is much higher than 35℃before October or after April. The greenhouses are vacant because of high or low temperature. The main problem which we must solve is how to increase the use ratio per year and reduce the energy consumption.According to the present situation in the northeast, the experiments and analysis of the greenhouse convective heat and mass transfer characteristic have been done. Firstly, the experiments and the analysis on convective heat characteristic have been done at the greenhouses perimeter zone underground. The perimeter zone soil is the main way that heat loosed from inside to outside of greenhouses because they are connected each other directly. Experimental results show that the vegetables on the perimeter zone of common greenhouse grow slowly. Comprehensive tests of temperature and thermal flux have been done on the basis of convective heat theory. Then three dimensional transient heat conduction models are established for soil heat transfer. Bioreactor with porous structure is good for insulate heat transfer underground. But because the temperature is too low in the northeast in winter, positive feedback of the bioreactor can not start. The bioreactor which has temperature control system inside can start at any time. When the temperature is higher than needed, temperature control system will transmit the surplus energy into underground storage pool, thus the reacting speed is reduced. Experimental results show that use of the thickness of 40cm,40cm depth about the biological reactor has a high cost performance, greenhouse temperature region decreased from 20%to 3%. Based on this analysis, porous sandwiching Benzene plate knee wall structure which covered temperature controlling bioreactor has effective temperature control function. This kind of structure not only has exothermic function but also has endothermic function. The study design to control the temperature of porous bio-reactor sandwich cover plate insulated hollow wall structure of benzene, so that the wall has a heat and endothermic dual function. Compared with ordinary brick structure results show that the temperature control range increase more than±3℃. Also, because water vapor in the air is absorbed by the reactor, the greenhouse humidity is reduced by 15%or more. Heat and mass transfer model in soil and wall experimental results,which get from soil and wall heat and mass transfer model, show that greenhouse temperatures can increase about 5℃, after the adoption of the above improvement measures. In the low temperature season, still can not meet the production demand, and in spring, summer, autumn three seasons. Adequate lighting is required to cool the excess heat can not be saved. After study the efficiency of heat exchange tube heat exchanger, the theory was found in the wall to set the wall roughness elements can increase the turbulence, can effectively improve the efficiency of heat transfer. Experiments show that in the case of non-heat pump, heat can be efficiently stored in the ground or extracted from the ground by using this kind of heat exchange tube. The storage pool is an area which surrounded by Benzene plate 2 meters underground in the greenhouses, and a layer of heating pipes is set in it. When outer light intensity is stronger or outer temperature is higher than the crop need, the circulating pump is started to take excess thermal energy into the storage pool. When the temperature is lower than the crop need, the circulating pump takes back the thermal energy to the greenhouses. Spring and autumn daytime energy storage can be balanced with the night, the stored energy in summer, and can be balanced with the winter.In this system, a kind of three time catalytic cracked biomass gasifier with computer control has been designed to meet the supplementary need of temperature and CO2, especially when the low temperature and solar radiation sustained continuously.Finally, an expert system for the northeast region greenhouse base on biomass has been constructed. It is a synthetical system which is made up of gasifier, eco-organic type soilless culture, bioreactor, and the underground thermal energy exchange system. BP neural network is used to deal with the dynamic data and control the system. Two kinds of vegetables, a cucumber named Zhongnong No.10 and a tomato named Zihuabao, was planted in the greenhouse to test the control result. During a production season test, the control system has been optimized. The control result demonstrates that the system's control performance can meet the need of vegetable production in Jilin province in winter. The system is based on virtual instrument software Lab VIEW, which has friendly interface and also has data self-culture ability. It would enquire the operator the control results at regular intervals, and then the control routine will update according to the new evaluation.The greenhouses are almost zero emission by using this system, and the ventilation would not be open frequently. The plant diseases and insect pests are turned away from the outside world because it achieves a closed produce system. The organic vegetables can be produced all year round, at the same time it uses significantly less chemical fertilizer and pesticide not only saving energy but also reducing pollution. The influence of uncertain factors has been reduced greatly by using the expert system. Not only the operation is easier but also production efficiency is improved effectively.
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