Optimization of Cooling and Heating Loads in a Residential Building in a Hot and Dry Climate

The purpose of this research is to study the amount of energy consumed by the residential building and attempts to optimize it. In this work, the heating and cooling load of a residential tower in a hot and dry climate in Tehran has been calculated by Carrier software. To optimize energy consumption, changes in the material and color of the exterior walls and the change of the window's type and also the examination of the presence of shades to reduce the heat transfer coefficient were made. Results indicate that the change in the type of window will reduce the thermal and cooling load significantly. By replacing the single-layer window with the double-layer reflex one, the thermal load required to provide comfort conditions in the building in the winter is reduced by about 40%. The shading on the windows and also the change in the color of the external walls have each about 3 percentages reducing effect on the thermal and cooling load of the building, that is of less importance in comparison with the effect of windows type. Also choosing optimized materials for external walls leads to about 9 % load reduction in the winter and 6% in the summer. Finally, by calculating optimization process cost and also the cost of consuming energy for the building heating and cooling, the Break-even point and the return cost time regarding to the changes in the material of the window and the exterior wall were investigated. In the best situation the return cost time is about 3 years.