Natural Ventilation Optimization Design In Large Space Building Based On CFD

As a kind of ecological construction technology natural ventilation can meet thecomfortable requirements of the room, save equipment initial investment, operation andmaintenance cost, create sustainable development of green building environment, improvebuilding ecological performance, enhance the affinity between building and natural..So howto optimize large space building natural ventilation design, improve the natural ventilationperformance of the building, reduce the construction of energy consumption has become a hotresearch topic. Previous research showed that, the research of large space ventilation is still inthe stage of individual cases. The quantitative and system analysis of natural ventilationdesign factors (large space building shape, the distance between air inlet and outlet, openingareas and so on) was not seen.This article first analyzes influencing factors of building natural ventilation, validates theaccuracy of the fluent numerical simulation through the theory model computation. Analyzethe natural ventilation characteristics of typical roof and profile form. The reasons and law theroof negative pressure produces and the thermal ventilation characteristics of typical roof andprofile form are summarized.Optimize analysis the influence of thermal ventilation designfactors in large space building, the recommended design indexes value of air inlet and outletareas and the distance between them are summarized. When the distance between air inlet andoutlet is0.3of the building height, the air outlet area is recommended2%~3.5%of the floorarea, the air inlet area is recommended4%~6%of the floor area.When the distance betweenair inlet and outlet is0.5of the building height, the air outlet area is recommended1.5%~2.5%of the floor area, the air inlet area is recommended3%~5%of the floor area.When the distance between air inlet and outlet is0.7of the building height, the air outlet areais recommended1%~2%of the floor area, the air inlet area is recommended2%~4%of thefloor area. When the distance between air inlet and outlet is0.9of the building height, the airoutlet area is recommended1%~1.5%of the floor area, the air inlet area is recommended2%~3%of the floor area. To ensure thermal natural ventilation distance, the building heightsuggests more than10m, and the air inlet height should be less than25%of the building. Theinfluence by the other ventilation factors (inlet air temperature, heat source strength andcoefficient of local resistance) is also considered. In the end by optimizing the naturalventilation effect by thermal pressure in an exhibition hall in Guangzhou the engineeringapplication value of this paper is illustrated.The result of this paper can provide quantization basis for large space building ventilation design, give significant engineering guide lines to the architecture natural ventilation andenergy saving design to some extent.