Analysis of the effect of window geometry on the thermal performance of the north and south facades of urban housing in the cold climate of Hamedan City

In a cold climate, it is necessary to correctly determine the window geometry parameters in order to access sunlight and improve thermal performance. The window is one of the main factors that can increase the demand for cooling energy in summer and reduce heating energy in winter. Therefore, the goal is to investigate the effect of window geometry parameters (WWR, U, SHGC, Shading) on energy consumption, in order to determine the optimal window level of the cold climate urban housing of Hamedan city. The ratio of the surface of the window to the wall and its geometric parameters, as an independent variable, and the amount of energy consumption, is a dependent variable.

The type of research is quantitative and based on the numerical data of the window-to-wall surface (WWR) and energy simulation, and statistical methods have been used in the analysis of the findings. In the data analysis, Pearson's correlation coefficient analysis, variance comparison analysis and follow-up tests were used to determine the relationship between the variables and determine the optimal level (WWR). This study in four stages; Investigating the window-to-wall surface ratio (WWR) of traditional houses, the effect of the WWR of the north and south facades of contemporary housing on building energy, the optimization of WWR due to variables (U, SHGC, SHADING) and the determination of the optimal level have been carried out.The statistical population of this research is in the first part of the selected houses of traditional housing in Hamadan city and to simulate contemporary housing, of the northern and southern parts in the new texture (conventional linear pattern) with an area of 240 square meters in each plot.

the results showed that; The southern front of traditional housing has 55.69% more glass wall surface than the north-facing front. In the contemporary context of Hamadan city, adding windows to the south-facing walls reduces the heating, lighting and final energy, and the north-facing walls increase the cooling, heating and final energy. The south-facing front has a better thermal performance than the north-facing front with a decrease in final energy (-21.55%). In cold climate, the lower the value of U and SHGC, the lower the energy consumption and the type of relationship is direct. For the north face, shading has no effect on energy consumption. But for the southern front, horizontal and combined fixed shading are effective and reduce cooling energy and increase heating energy, so to prevent the increase of heating energy due to the creation of fixed shading, movable shading can be used, Or it is better to reduce the amount of heating energy consumption by increasing the vertical distance of the awning from the top of the window.

On the south front, the optimal window-to-wall level equal to 60% WWR has a final load reduction of -18.52%, and on the north facing front, WWR = 40% has a final load reduction of -8.38%. Based on the results, a revision proposal has been presented in Appendix 10, Topic 19 of the National Building Regulations.