Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Effect of Window Glazings' Visible Transmittance to Daylight Factor and Energy Efficiency in an Architecture Studio
by Elif Gundogdu and Arzu Cilasun Kunduraci

Abstract:
Daylight is a demand of living in a closed space. The use of daylight can contribute to energy savings of a building and can improve the well-being and job satisfaction of occupants. Therefore, designers generally aim to obtain daylight usage for interiors. However, when daylight is not well-designed it may cause glare. Glare is an unwanted outcome of receiving light and when it occurs, visual comfort cannot be obtained. When glare occurs, it may cause energy consumption to increase as well. Because users may close shutters/curtains to block excessive daylight and turn on the lights. Furthermore, cooling loads might increase due to extra heat gains. In both cases, energy consumptions increase because of excessive daylight. To achieve an energy efficient and well illuminated space, openings play an important role with their glazings, frames and shadings. Nowadays, the improved technology supports different variety for all of these components. Therefore, when they are carefully selected, they can ensure energy savings. Studies present that glazings with different visible transmittance values (VT) can affect the energy consumption; when low VT glazings are used, the amount of light entering the space and overheating reduces. However, since the daylight is blocked, illuminance levels may be insufficient and the need of using artificial lighting may arise. On the other hand, when high VT glazings are used, due to extensive daylight, overheating and glare can happen. Prolonged exposure to glare can result in headaches and eye fatigue. It is important to design openings to have optimum daylight by using appropriate window size and window components. Within the scope of this study, the contribution of different VT�s to energy consumptions are examined. This research investigates the relation between different glazing visible transmittance values (VT 90, VT 70 and VT 50) and energy efficiency of space. The study was carried out in a south facing studio of Ya?ar University in ?zmir, Turkey. The energy efficiency simulations where carried on DIALux software and results were evaluated in accordance to EN 12464-1. The results obtained in this paper is to suggest glazing VT values that can be used to reduce energy consumption while having a daylight integrated space with an access to outside view.

Keywords: Daylight, Window Glazing, Energy Efficiency, Daylight Efficiency

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