Research On Heat Transfer Characteristics Of Skylights And Inner Shading Devices In Tall-Large Building Spaces At The Cold Region

Public buildings consume lots of energy. Its atrium and tall spaces are the places need to focus more on energy saving. This research aims to study heat transfer mechanism of a system—system combine transparent envelope and inner shading devices at the top of these spaces. It provides some suggestions for a better building energy design and more comfortable indoor environment. Buildings at cold region need cooling in summer and heating in winter, it is important to set the air conditioning load control method and shading coefficient limits for atrium spaces with skylights, which rare appear in Chinese public building design standard.Firstly, field studies are made at Beijing-Tianjin region to collect public buildings' skylight shading systems cases. The differences between the actual weather data and the standard meteorological data are also being analyzed during this stage.Secondly, based on large number of cases, the basic patterns of inner shading devices are summarized: shade structures and a sheet of fabric. It is used to describe a particular geometry and its thermal parameters. Then, the heat transfer process through the structure of skylight, shading devices and the tall space is described. Three key indicators of this process within energy conservation node equations are put forward.?1? q_b,diff(or q_z,diff)- shortwave radiation scattering intensity through the virtual plane SH?;?2? GradientT?H?- the temperature gradient within Model-2 space;?3? q_St-- energy transmittance cause by solar radiation at the test plane.Finally, in order to measure these parameters, reference to foreign test equipment and testing requirements of this research's own characteristics, a test device is designed and built up. Two kinds of shading components were tested. Test results show that the transmittance of scattering short-wave and the total radiation intensity was nearly a linear relationship; the total heat flux of St is a power function of the total radiation intensity at daytime, and during the night the most important affect factor is skylight radiation temperature.CFD simulation trials are also conduct to proof the accurate of the testing device. Some possible factors, such as RH,Rg,h, normal and scatter solar radiation intensity, are studied to extend the conclusion of this study.Thermal processes and analytical methods within the skylight shading system is studied under the theoretical and experimental methods. This laid the theory foundation for future study.