Optimization of energy transmittance through building envelope for hot dry climate

Abstract

Fenestrations of the buildings are playing an important role in the building’s energy efficiency for the tropical climate. The energy that comes from the glass window into the building can be restricted by providing shading on the windows. So, to provide the shading on the window, the most common way is fixed shade like overhang and fin. Shading devices are very helpful to control the SHGC and light transmittance through the fenestrations of the building. Most of the studies analyze the impact of WWR, shadings, and SHGC on a building’s energy demand but did not consider the combined effect of these parameters. By considering all the parameters of the building envelope in the analysis like WWR, orientation, shading devices, projection factor, and type of glass, the energy demand in the building can be significantly reduced. The goal of this paper is to analyze the variation of residential envelope transmittance value with the window-wall ratio, projection factor, and fixed shading devices and also to optimize the energy from building envelope elements in residential buildings using a statistical method, namely the Taguchi method. The transmittance of energy through the building envelope is calculated in 8 cardinal directions by providing shading with the fin and overhang. Based on the result, the optimum energy saving achieved by selecting the optimum combination of the process parameters for minimizing the energy from the building envelope is A1B1C3D2 i.e. window to wall ratio 7%, triple glazing type of glass used, shading with the overhang fin, and orientation in the west direction. The result shows the most significant factor among the selected parameter is the window to wall ratio. Also, by focusing on the building envelope parameters, an architectural designer may reduce the building energy demand significantly and offer more alternatives to achieve energy-efficient buildings.