Economic Analysis and Assessing Energy Performance of Simulation-Powered Optimal Window Type and Window to Wall Ratio for Residential Buildings in Tehran

Sustainable development as a process for meeting human development goals has an undeniable impact on all aspects of human life while sustaining the ability of natural systems to continue to provide the natural resources. In spite of worldwide climate change problems caused by fossil fuel use, energy consumption levels in Iran are already high and continue to rise each year. About 40% of energy consumed by the residential buildings in this country is fossil fuel-derived. Therefore providing solutions to reduce energy consumption in this sector is very important.Tehran is the largest city of Iran and significant amounts of energy are consumed in this city. However, due to its location in semi-arid climatic region, it benefits from high sun’s radiation even in winter and low relative humidity of the air. There is high potential for energy conservation in residential buildings of Tehran. Therefore the introduction of energy efficient buildings in this city would have a significant overall impact on national energy consumption levels.Nowadays, sun shading devices are one of the most efficient elements to manage the interaction between the interiors and exteriors of buildings. They can significantly reduce cooling energy demand, improve thermal comfort, prevent the heat loss in the winter and reduce potential glare problems in residential ( (also in office and commercial) buildings.Sun shading devices can be categorized according to their placement as interior, exterior and mid-pane. Result of research and studies shows that the effectiveness increase 35% by using outside shade protection instead of inside one. This research is aware of this fact that optimized internal sun shading devices are not comparable with the external sun shading devices in efficiency and performance. Although due to the increased utilization of them in the residential buildings, this research studied the internal sun shading devices and determined the optimized internal sun shading system, and then analyzed its effect on the energy consumption in the residential building model.In this study at the first phase, the combination of four types of internal sun shading devices with three types of windows are evaluated by the Parasol simulation software to determine the optimized internal sun shading system. Simulations show that the double glazed transparent window with white dense reflective Blind ( (as optimized sun shading system), has most appropriate thermal behavior.At the next step, a building model as a case study ( (The six-story apartment in the city of Tehran) was considered for simulations of energy consumption. The Building Calc. software was applied for energy simulations and heating, cooling and total energy consumption of building was calculated with and without optimized internal sun shading system. The result shows that efficiency of internal sun shading devices increase by using dense texture, high reflectance and low transfer rate.Energy consumption of residential buildings in Tehran reduced up to 14% only by using optimized internal sun shading system. This method could be one of the best solutions to reduce the energy demand in residential buildings because of the large coordination with Iran’s economic, cultural and social conditions.Keywords: Sustainable development, Energy conservation, Sun shading system, Internal sun shading device, Energy consumption simulation.