Experimental and Theoretical Studies of Various Glass Materials and its Orientation for Optimum Heat Gain and Optimum Day lighting in Buildings

Abstract

The commercial buildings use glass as main building material. The extensive use of glass in buildings increase cooling load of the buildings. This report presents the key findings, conclusions and recommendations of a study that was conducted to control heat gain through various tinted and reflective glasses. The optimum orientation and tilt of the window glasses have been proposed in the report to control heat gain in the buildings. The radiation passing through glass depends on solar optical properties such as solar transmittance, reflectance and absorbance. This report presents spectral characteristics of clear, bronze, green, grey, bronzereflective, green-reflective, grey-reflective, opal blue reflective, sapphire blue reflective and gold reflective glasses which are measured experimentally by double beam ratio Perkin Elmer Lambda 950 spectrophotometer. These spectral characteristics are used to find the visible optical properties in the visible spectrum wavelength region (380nm-780nm) and solar optical properties in the total solar spectrum wavelength region (300nm-2500nm) as per British standards. The results of the report propose following best glass in single and double glazing window combinations to reduce total solar heat gain through glass windows in buildings, energy and cost saving annually for various climatic zones. The heat gain and adequate daylight factor were computed for different building of composite climatic zone (New Delhi) using various reflective window glasses like single and double glass windows in Design Builder and Energy Plus simulation tools. From the results, it is noticed that the green reflective glass window observed to be the best in summer and bronze reflective glass window is best in winter in single reflective glass windows and double gold reflective glass windows is observed to be energy efficient in both summer & winter seasons due to its optimum heat gain and adequate daylight factor in buildings. From the results it is also noticed that best shading device along with window to allow optimum heat and daylight factor levels inside the different buildings to meet the requirements as per standards. The results of the report propose the best energy efficient single and multiple pane glasses, optimum orientation and tilt of the glasses for energy efficient solar passive building construction.