Research On Heat Preservation Performance And Energy Conservation Effect Of Ultra Low Energy Comsumption Greenhouse

Greenhouse could be capable of proceeding with winter production with less heating or without heating and realize the aim of yearly production, which is one of agriculture facilities possessed clear-out rignal characteristic in Chinese agriculture production activates. Because of above reasons, there is a wide extension and utilization of greenhouse existed in Northeast, Northwest and most of North China, and defects of growing in open fields that are interrupted production and low yield caused by varying seasons would be filled up effectively, and provide a stable supply for agriculture market. To accompany the promulgate of national agriculture facilitiy promotion policy and the development of energy saving greenhouse during Nationl eleventh five-year plan, the constructional intensity of greenhouse in North area of our country is enhanced further,80% of greenhouse quantity including constructed and constructing projects are common greenhouse, the first generation energy saving greenhouse and the second generation energy saving greenhouse, and the third generation energy saving greenhouse is still on the beginning of popularizing phase. The paper gives a review on developing expericnce of Chinese greenhouse, and presents the summary that the aim and trend of Chinese greenhouse development are energy saving, the promotion of intensive production, and building up a greenhouse possessed with performance of low energy consumption and high ecological benefits.Except for the bearing capcity of greenhouse structure, the protective wall plays roles of thermal insulation, retaining heat and maintaining the indoor temperature. The protective wall area makes up 50～60% of the protective structure, consequently the thermal insulation and retaining heat behavior of the protective wall presents a direct effect on the greenhouse insulation capacity, and through optimizing the constructional wall style and introducing therrmal insulation into the wall, the way of promoting thermal insulation and retaining heat performance of the protective wall and tapping the potential of energy saving is great effective for the development greenhouse. The paper adopts thermal insulatin mortar of Glazed Hollow Beads which is the research production of the group on the outer part of the protective wall, and introduces the phase change material-paraffin wax into thermal insulation mortar of G. H. B. that develops thermal insulation and phase change mortar and constructs it on the inner part of the protective wall as retaining heat layer with brick wall, when the great fluctuation of indoor temperature happens, surplus heat would be stored and liberated by thermal insulation and phase change mortar layer of G. H. B. so as to realize the aim of "peak load shifting" effect. Not only good thermal insulation and retaining heat performance possesses the composite protective wall but also great decrease in the wall thichkness that should retrench the occupation area of the protective wall and improve the land utilization ratio under the ensurement of indoor temperature in the greenhouse. On the basis of above research, the paper puts forward a constructional plan of ultra low energy consumption greenhouse and selects Liaoshen I greenhouse which is the repsentative of the second generation energy saving greenhouse as the comparing object to research on thermal insulation performance and energy saving effect of ultra low energy consumption greenhouse.Here are main chief contents:1. Designing and manufacting scales of ultra low energy consumption greenhouse and Liaoshen I greenhouse, the paper tests indoor temperature and outdoor temperature of models of 13 hours of varying day form 18. Jan to 24. Jan in 2010, and compares and analyzes testing results, and gives a conclusion that indoor temperature average value of ultra low energy consumption greenhouse model is average 2.47℃higher than LiaoshenⅠgreenhouse model average value.2. Through adopting infinite element software ANSYS and ANSYS/Flotran, the paper presents the steady state and transient thermal analysis and CFD simulation for ultra low energy consumption greenhouse and LiaoshenⅠgreenhouse, in theory, provides verification and analysis for comparing testing results of ultra low energy consumption greenhouse and LiaoshenⅠgreenhouse. 3. Choosing heating energy consumption and land utilization ratio ratio as energy saving indexs, the paper compares energy saving effects of ultra low energy consumption greenhouse and Liaoshen I greenhouse, during 2009～2010 winter heating period, special heating expense for ultra low energy consumption greenhouse is 254.5 Yuan lower than Liaoshen I greenhouse and land utilization ratio of ultra low energy consumption greenhouse is 2.2% higher than Liaoshen I greenhouse.Through above research contents:Compared with present energy saving greenhouse, thermal insulation performance and energy saving potential of the greenhouse is improved and tapped by ultra low energy consumption greenhouse, and ultra low energy consumption greenhouse corresponds to Chinese greenhouse developing direction and possesses wide popularization and application value.