Energy performance enhancement and the role of green-roof in an existing building in Isfahan: adaptive study between code No 19 and ASHRAE 90.2:2018

In the present study, the energy performance of a villa building in Isfahan was studied during a year using DesignBuilder (Ver. 6.1) and the results were evaluated with energy bills including both gas and electricity consumptions. After identifying the energy performance weaknesses of the building, the skin was enhanced in two scenarios to meet the requirements of code No 19 and ASHRAE 90.2. It is found that the energy required for cooling and heating of the existing building can be saved by 63% and 70%, respectively, in compliance with the requirements of code No 19 of and ASHRAE 90.2. The results also show that despite all the weaknesses of code No 19, the energy intensity of the building's sector in Iran can be saved considerably only by following the regulation. The role of green roofs in terms of the energy saving in these two scenarios was also studied. In addition to other benefits of green roofing from architectural and environmental perspectives, an extra reduction in energy consumption by 9.5% and 4% can be achieved by a typical green-roof in a building based on code No 19 and the requirements of ASHRAE 90.2.