study of the urban form effect on operational energy consumption; the case of shiraz

reducing energy consumption and greenhouse gas emissions have become a worldwide necessity. iran has the sixteenth ranking position of global greenhouse gas emissions and its rate of growth is above global average. built environments are responsible for about 40% of energy consumption and it is generally approved that the greatest portion of built environment is dedicated to residential land use. thus improving energy efficiency of the existing dwelling stock in urban regions will increasingly be part of achieving sustainable development in future. therefore the main goal of this article is analyzing the sustainability of urban residential sector with focusing on operational energy consumption (energy consumed during the in-use phase of a building's life which is their biggest environmental impact). for this purpose we calculated the operational energy consumption of residential sectors (annual sum of gas and electricity consumption) and study it’s correlations with urban form characteristics. to do this urban form characteristics influencing energy consumption of residential sector were chosen regarding literature review (independent variables). these variables include plot orientation, quality of the building, prime material of the building façade, building archaism, structure of the building, area of the plot and some other influencing characters. data regarding gas and electricity consumption of residents (dependent variables) were gathered via contacting related organizations. in this regard the next step was to transfer these energies to joule unit. residential sectors were divided to seven different dwelling types including central-yard houses, attached terrace houses (one, two and three stories), apartments (above 3 story buildings), and villas and declined houses. to better understand effects of urban form on residential energy use we normalized energy consumption data with housing areas. several important conclusions were derived from correlation coefficients including the strong correlate between dwelling type and capitation consumption of operational energy. it was also specified that there is a mediocre correlate between capitation consumption of operational energy and quality, archaism, structure and area of the plot. in calculating operational energy of residential buildings, we found out that central-yard houses with 65 gj/m2 are the least energy efficient dwelling type among others. the most energy efficient dwelling type couldn’t be determined between villas with 8 gj/m2  and declined houses with 14 gj/m2  via the data base of this study. in anova analyses, other important outcomes could be summarizes as follow: “concrete and steel structures” consume less operational energy per capita than “brick and iron” and similarly “brick and iron” structures consume less energy than “clay and wood” structures. furthermore we discovered that buildings solar gain and operational energy consumption per capita have inverse relationship with each other. it is also evident that those buildings favoring south sunlight consume less energy than central yard buildings (which are in advantage of the four dimension sunlight). statistical analyses also revealed that with a little connivance dwellings dating back to over 60 years are the least energy efficient types while newly built dwellings (less than 5 years) are the most energy efficient housing types in operational energy consumption per square meter.