Research On The Structure Optimization Of Solar Greenhouse In Anhui Province

With the adjustment of China’s agricultural policy, and the rapid development of the rural economy, economic, efficient and energy-saving solar greenhouse has been widely applied in the off-season producing. Although the northern areas’winter is long and cold, but they are suitable for greenhouse production with enough illumination time in autumn and winter. Therefore, producing vegetables in winter in the northern areas has become one of the most important ways to increase income for farmers.Solar greenhouse, a new greenhouse for farmers, is created by China, the energy-saving solar greenhouse can produce vegetables without extra heating in winter, has been popularized at north, northwest and northeast of china. Greenhouse’s being introduced should consider the climatic characteristics in the region, with the advantages with local climate resources for the reconstruction of the greenhouse structure, so as to make it better be adapted to the local producing. Copying foreign greenhouse structure and supporting technology blindly will cause energy waste and poor producing efficiency.This paper mainly studies the greenhouse in northern Anhui Province to find suitable development mode on heat preservation, based on status and trend of domestic and foreign development of facility agriculture, by analyzing indoor and outside light intensity, temperature (including indoor, outdoor air temperature and soil temperature) of two solar greenhouses with different structure by continuous observation in the agricultural science and technology demonstration park in of in Xiangshan District, Huaibei city, Anhui Province. Through the analyses of the data, preliminary master the greenhouse temperature lighting performance, and by the analysis of experimental data, the relationship between lighting and temperature. Based on the experimental data analysis, the strength of illumination in greenhouse is transparent from the outside of the greenhouse illumination intensity and greenhouse rate decision, the inside temperature of the greenhouse changes by the outside temperature and the light changes. The analyses of the summarization of heat preservation method being used in greenhouse in northern China provide a powerful reference to improve the greenhouse heat preservation and increase economic benefits.Through analyzing the two greenhouses’ light performance, V greenhouse’s light intensity is higher than I greenhouse, has a better lighting performance. Light indoor is strongest interval appear in around12noon time, the indoor illumination distribution is uneven, the average light in front of the strongest, gradually weakened to the north. East near the gable area due to blocking effect of gable, appear weak light region in the morning and evening, because of different incident angles, the front of greenhouse has a stronger illumination than the middle, the middle is stronger than the rear, the rear is the lowest. Different greenhouse location has a different light transmittance.The temperature in the greenhouse changes by the change of outdoor temperature and illumination. Being compare with the outdoor temperature and illumination, the highest indoor temperature appears delay about1～1.5hours. The middle illumination condition is good, with good thermal insulation properties. So the indoor temperature distribution is not uniform, the middle is the highest, lower at two sides. Two indoor temperatures’ difference is big, the difference of the highest temperature in two greenhouses is2.℃, the difference of the minimum temperature is2.9℃. With the same management measures, two greenhouses’ warming performances are near, I and V greenhouses’ average temperature increased by2.29℃and2.2℃per hour. The temperature in V greenhouse with a period of20℃extended30-60min than I greenhouse.Soil temperature followed the indoor temperature’s change, the indoor temperature is higher than the surface temperature, the ground is an endothermic process, and decreased with increasing soil temperature with depth; night ground in the exothermic process, the ground is deep, the higher soil temperature. The underground temperature of10cm peak appears at14:30,16℃than at indoor temperature. The highest point delays about3hours. The average temperature underground10cm in two solar greenhouses are from13.9to15.7℃, the I greenhouse is13.9℃, the V greenhouse is15.7℃. The average temperature of the V greenhouse is1.8℃higher than the I greenhouse. The temperature in the front of the greenhouse is low, the middle temperature is close to the rear with small difference. The relations between soil temperature and indoor air temperature are close, the low air temperature causes low soil temperature, high air temperature causes high soil temperature.