Numerical Simulation And Experimental Research Of Heat Transfer Characteristics Of Building Energy-saving Window

Windows is indispensable components in building enclosure, which is the most active part of the heat exchange. The energy consumed through doors and windows have been accounted for40%to50%of the total energy consumption in building enclosure. As a result, it is very important to make a study for the heat transfer characteristics of the windows. Combined numerical simulation with experimental study to analyze the heat transfer characteristics of the each system in the typical energy-efficient windows, analyze how the walls impact the heat transfer characteristics of the whole window, explore the factors affecting heat transfer of each system, and how these factors affect the heat transfer coefficient of the whole window. Make it clear that which is the critical parts for the window in energy saving and which is the key factor. Making some improvements for the existing calculation methods, of which the numerical simulation can be realized by the Fluent, CAD or other relevant software. To make experimental study, doors and windows insulation performance test rig in building and plate thermal conductivity tester needed.Divided into three parts, that is to say, glass system, window frame system and the whole window system. Mainly analyzing the aspects that the dimension of the models, the factors which influence the heat exchange of the glass system and window frame system, the computing method to calculate the heat transfer coefficient of the whole window system and how the walls affect the heat exchange of the windows. At last, verifying the simulated result based on experiments and analyzing why errors generate.Starting with numerical simulation, expounding the principle, the method and the boundary conditions of numerical simulation. Having known that how to choose physical models of different dimensions for the various parts of the windows, how the radiation and the convection influence the window frame system, the suited thickness for the cylindrically curved glass in different climate zones, how the physical properties of material influence the heat transfer coefficient of the window frame system, the superiority of the improved algorithm for the linear heat transfer coefficient and how the walls influence the heat transfer coefficient of the whole window system. Coming to a conclusion that three-dimensional physical models are only needed in vertical window frame, for other parts, very precise results will be got by useing tow-dimensional physical models. However, to calculate the he heat transfer coefficient of the whole window system, there is little difference between three-dimensional physical models and tow, which is1%. The thickness for the cylindrically curved glass vary from a city to another in different climate zones. In fact, the thickness mainly depend on the convection outdoors, so that, the most thickest ones may not be fit in the coldest zones. Making it easy and fast to model by applying the linear heat transfer coefficient. The walls affect the heat transfer coefficient of the whole window on the position where the windows is on the walls and the thermal conductivity of the walls. The value will vary from an operating condition to another.Talking about experimental study, elaborating the principle of the experimental equipment, introducing testing method and presenting testing process. And then, making a test on typical energy efficient window to get its the heat transfer coefficient of the whole window. Completing the experimental results the results of numerical simulation, showing that a difference of6%. At last, explain why the errors exist.