Research On Soil Wall Of Solar Greenhouse And Simulation Of Its Temperature Environment

Solar greenhouse is an important type of agriculture facility in northern China. For findingout the effect of walls to the solar greenhouse insulation and the effect of ventilation time to thetemperature environmental change in the solar greenhouse, solar greenhouse built of soil wallsin Yangling, Shaanxi was the research object of the study. Thermodynamic indicators of soiltest blocks made by18kinds of different experimental soil moisture content and differentcompaction work were measured. And according to the indicators,18kinds of thermalinsulation properties of solar greenhouse soil walls built in different building conditions werecomparatively studied. Based on the results of the test, preferable solar greenhouse wallconstruction condition was definitively outcome.The paper analyzed the cost structure of earthwall system of solar greenhouse in energy_saving project and a technical and economicalevaluation index. According to the greenhouse load level and price cost in Yangling, Shaanxi,the relationship between energy_saving project and wall thickness was studied. Then wecalculated the optimal construction of the wall thickness of the solar greenhouse under theconstruction condition, checked the wall’s structural stability by mathematical calculations.Then using the CFD method, this paper analyzed the temperature variation and distribution ofsolar greenhouse with different ventilation time. The main findings are as follows:1. According to the18solar greenhouse walls constructed under the conditions of thethermal resistance of the wall, the heat storage coefficient, thermal inertia indicators, thecomprehensive analysis result as below: The15.5%soil moisture content earth used inconstruction and591.6kJ/m3compaction energy per unit volume as the building conditions ispreferable in the more economically province and good insulation properties. The optimizeresults of the study of the solar greenhouse wall thickness under the ideal constructionconditions show that: When the constant is43.08yuan per square meter, the maximization ofthe energy saving and unit cost is1.3m on the basis of basic construction thickness of1.3m. Sothe optimal construction of the wall thickness of Yangling solar greenhouse is2.60m.2. The results of overturning checking and anti-slip checking of the2.6m thickness soilwall under construction of15.5%soil moisture content earth used in construction and591.6kJ/m3compaction energy per unit volume as below:K tC≥1.5,K tB≥1.5,K s≥1.3. Theresults illustrate that the greenhouse walls under the construction conditions and construction thickness can meet the demand of anti-overturning and anti-slip and ensure the stability of thewall structure.3. The research results of Walls solar greenhouse temperature environment as below:According to the level of alpha=0.05, CFD environment of solar greenhouse temperaturedistribution does not exist significant difference between simulated values and measured values,shows that using CFD can more accurately simulate the distribution of the temperature insidethe greenhouse environment situation and change.Through the simulation of the nighttemperature under different ventilation time environment, analysts believe that spring solargreenhouse ventilation at9:00in the morning, ventilation8h for the optimal ventilation time.The method used outside environmental conditions to simulate the environmental conditionsunder the temperature of the day of the solar greenhouse. Its successful validation and use willbe the premise and foundation for the future establishment of a solar greenhouse ventilationtime model under different ambient conditions.