Study of Optimum Inward Glass Tilt Angle for Window Glass in Different Indian Latitudes to Gain Minimum Heat into Buildings

摘要

Modem buildings use glass materials for building enclosures. Extensive use of glass in building envelopes increases the heat gain, which in turn increases the energy demand to maintain the building at comfortable conditions. This paper presents experimentally measured spectral optical properties of four different glass materials such as, clear, bronze, green and reflective glasses. The solar optical properties were computed using spectral optical properties. The effect of inward glass tilts to gain minimum heat into buildings for different latitudes of India with four different glass materials for energy efficient glass window design was studied.. The optimum glass tilt for different Indian latitudes such as, 9°, 13°, 17°, 21°, 25° and 29° in all orientations of the window glass (E, W, N, S, NE, NW, SE and SW) were computed. From the results it is observed that at 9° and 17° N latitudes minimum heat gain is found to be in south direction for the vertical position of all the glasses. For 13° N latitude, 4° inward tilt of the glass is observed to be optimum in south direction. For latitudes 21° and 25° N, 2° inward tilt of the glass is efficient in south orientation. 29° N latitude requires an inward tilt of 6° for glass materials to eliminate solar radiation passing through the glasses in south direction.