Analyze Building Energy Use By Modeling The Interactions Between Building Exterior Openings, Day-lighting And Natural Ventilation

The opening of building facades has a strong influence on daylighting, thermal performance and natural ventilation. However, in regard to the opening form of building facades, architectural designers usually pay attention to aesthetics aspect and neglect the influence of changing the opening form on the energy consumption of the buildings. As more and more social focus on energy consumption, the relationship between the opening form of the building facades and the building energy consumption becomes worthy of intensive study. However, making full use of solar energy and natural wind to reduce energy consumption and designing good architectures is a challenge for architects. The aim of this study is to explore the form principles of low energy building design from an operable aspect and grope for efficiently analytical route, which could integrated analyze daylighting, thermal performance and natural ventilation of building facade openings, according to the evaluation demand in the scheme design phase. The technique could provide an effective method to achieve multi-objective design controls in the design stage.The thesis constructs a suitable integrated model for this research and develops a whole building environment simulation software, which is called DatSim, for daylight, airflow and thermal performance by Matlab, through the comparison of existing daylignting thermal and natural ventilation module’capability. The software has an interactive graphic user interface which could easily solve the problem of the analytical model in the operable aspect. The research establishes a series of parameters setting principles for the simulation method by the comparison of the simulation and experimental results. At last,1151 group of experiment designs are performed to prove the validity of the analytical route and some primary design control guide lines are summarized.The research result indicates that coupling daylight factor model and multi-zone network model with energy simulation model is more suitable than coupling Radiance model and CFD model with energy simulation model for this research to meet the demand of calculation precision and speed. However, when multi-zone network model is used to calculate the natural ventilation, the surface non-averaged wind pressure coefficients are needed to nicely reflect the influence of the opening form and position changes. And for the gaining of wind pressure coefficients, the research deems the CFD method may be the only effective way for the uncertain design scheme’s analysis.Aiming at the integrated analytical model, the research develops the relevant building full environment automatic simulation software DatSim, the software platform can automatically establish the geometrical form data and boundary condition data, adopt Energyplus and Fluent engine to carry out annual integrated simulation for daylighting, thermal performance and natural ventilation, automatically analyze the simulation result and linkage display the design change. The platform establish a solid foundation for analyzing the principle of the building facade opening design and provide a effective approach for the computer aided architecture design.Based on Datsim,1151 different design cases have been modeled. The simulation result shows that opening area, compared with opening positions, exerts a greater influence on energy consumption. So it need more consideration in the design stage. From integrated point of view, the south window to wall ratio should be controlled from 25% to 40% and the north window to wall ratio should be controlled around 20%. Under no shading conditions, the influence of the horizontal position change on daylighting can be ignored, when the window to wall ratio is above 30%. The influence of the horizontal position change on natural ventilation can also be ignored, which this influence is small:below 5%. Under vertical shading conditions, the distance between the window side to the shading wall side should be above half of the shading wall extrude size. For the vertical position change, the south window should be at the middle of the wall and the north window should be at the 2/3 height of the wall.