| Summary: | 碩士 === 中原大學 === 建築研究所 === 101 === Abstract
This study discussed the influence of the glass with different light transmittances and membranes at different incident angles and sun azimuths in different seasons on indoor daylighting. The scale ratio model was used outdoors for field measurement. Empirical study and measurement validation were conducted. Graphic analysis and computer were used to created values to assist the designers with rapid and correct judgment effectively on the fitness of building opening glass. The influence of the glass with different light transmittances and membranes on indoor light environment could be known.
The measurement result of glass transmittance proved that the light transmittance of glass is in straight forward proportional relation to the ratio of illuminance measured indoors and outdoors. However, there were significant differences in the ratio of illuminance of the glass with the same light transmittance measured at different azimuths due to different sunlight projection directions. There was no constant ratio between the value of uniformity and the visible light transmittance of glass. The north facing window glass was free from perpendicular incidence, the uniformity of the measured numerical values was higher. Due to the azimuth and altitude of sun, some measuring points on the south facing glass received perpendicular incidence, so the uniformity was lower. The application of glass transmittance should consider the demand for indoor daylight factor and the orientation factor.
The ratio of illuminance of indoor and outdoor measuring points was tested in the experiment on light transmittance of glass membrane. The measurement validated the daylighting effect. When the shielding rate was 25%, the membrane at 1/2 of lower part of 1 * 1cm grid was better than full area covered with membrane which was better than membrane at 1/2 of upper part. When the shielding rate was 25%, the daylighting effect of 5 * 5cm grid with membrane was better than the 2.5 * 2.5cm grid with membrane at shielding rate of 25% which was better than the 1 * 1cm grid with membrane at shielding rate of 25%. The uniformity of upper part with membrane was better than the full area with membrane, and better than the lower part with membrane.
This study only measured the glass without shading facilities. It is expected to add shading facilities to the experiment on glass transmittance in the future for actual measurement, so as to further learn about the conditions of glass in practical application. In the indoor environment index grading standard of green building definition and evaluation manual (2012), the glass transmittance inspection standard only uses the glass transmittance as the basis of grading. Whether the orientation factor shall be added in. The curtain glass and convex shading facilities of high-rise buildings inconvenience the future long-term maintenance, whether the heat transfer can be reduced and the daylighting efficiency can be increased by using membrane. The design of affixing membrane to glass photovoltaic panel can control the daylighting efficiency effectively, even conforms to economic benefit.
Keywords: glass; daylighting; ratio of illuminance; uniformity
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