The Effect of Neighborhood Shading on Building's Energy Performance, Case Study: Isfahan

Abstract

The sun position during building heating and cooling annual period has a major influence on the energy efficiency performance and must be adequately taken into consideration in the design process. Recently, in big cities the design and construction of energy efficient buildings has become a priority. This goal can be accomplished if natural resources such as solar radiation are wisely exploited. The real challenge, is to find clever compromises between urban and building design. For example, one of the major issues that causes trouble for people living in residential districts is insufficient solar gain and natural lighting of building interiors. Shadings caused by neighborhoods induces improper lighting condition and high energy consumption. These shadings can be caused by buildings, placed in opposite side of alley, although the design is performed in accordance with urban regulations. Shading could have positive effect on building's energy efficiency in summer, while its impact is disastrous in winter. Sun path drawings show that the shading effect of opposite side buildings is not considerable in summer, due to high solar altitude angles in Iran's central cities. In this study, after defining buildings typology, construction materials and window to wall ratios in Isfahan City, simulations are conducted with the aid of Energy Plus software, to investigate the influence of different parameters, such as opposite building's height on energy performance (annual heating and cooling loads). Daysim software was also used to compare daylight factor in sample model. The results show that urban codes, where the solar latitude during the heating and cooling period is not taken into consideration, should be optimized in regard to width of alleys and buildings' heights. As a result, modification of related urban codes must be proposed and setback lines should be optimized to reach more efficient and lively habitats.