Research On Indoor Thermal Environment Of Greenhouse In Cold Regions

With simple structure and maximum usage of solar energy,Solar greenhouseis widely used in prodution of agricultural plants, while it also meets challange inbitterly cold region because of limits of its materials and structure.Thetemperature inside greenhouse plays an essential role in plans’growing, andenergy consuming reflects whether the design of solar greenhouse iseconomically reasonable as well. Owing to praise numerical simulation, CFD iswidely spread in simulating temperature fileds and velocity fields,etc. In possesof large latent heat-storage capacity,the phase change materials are widelyadopted inside greenhouse to store or dissipate heat according to changingtemperature, which plays a balanced role contributing to the temperature fieldsand energy saving.Based on numerical imitation calculating technology of CFD&MATLAB,this thesis takes solar greenhouse in cold region as object,and doesrelevant studies and analysis on solar greenhouse’s design load, annual heatconsumption,temperature fields and velocity fields inside greenhouse. Specificprocedures and relevant conclusion are as following:1.By establishing physical model of solar greenhouse, we can get thefollowing respective data, the design load of greenhouse is0.323KW/m2, the heatloss of plastic films accounts for93%of total heat loss, the heat of solar radiationis0.110KW/m2. Under outdoor meteorological parameters, theoretically annualvolume of heat loss of this sort of plastic films around Harbin is1.753GJ/m2.2.By establishing mathematical model of solar greenhouse and usingFLUENT-a series of software ANSYS to stimulate3D. Temperature fields,velocity fields, and analyze temperature distribution in each profile of solargreenhouse, we find it has a balanced distribution, and the temperature aroundback wall is highest.3.By establishing physical model of “Phase Change Greenhouse’’ and usingMATLAB calculates respectively the indoor hourly temperature of commongreenhouse and “phase change greenhouse” ona typical day in Harbin, and“phase change greenhouse”has obvious energy saving effect throughout theheating period.