Analysis of the effect of green building technique on reducing energy consumption (Green roof technique in an educational building in Wasit, Iraq)

Iraq has mild winters and hot and dry weather in long summers, that's why cooling has become the most energy-consuming aspect in Iraq, and the amount of energy consumption is increasing. This problem lies in the unwillingness to use the ways of green building, which is done with the aim of reducing the consumption of energy and natural resources. Therefore, this research focuses on one of these strategies, which is the green roof as the best way to save energy. The purpose of the research is to present an example of roof design using green roof technology in an educational building in Wasit city, and to evaluate the thermal behavior of this technology in improving energy consumption.

 This study was done analytically through the Design Builder program to evaluate the effect of green roof on energy consumption of six types of native plants selected for the climate of Wasit. There are many research variables such as plant height, leaf area index, and growth layer height as research variables, through which the improvement in annual energy consumption is measured.

The results of the numerical analysis showed that after comparing the plants, the best thermal performance of the green roof was for two plants with a height of 15 cm and 20 cm with a high leaf area index. It was 4.43 and 5.82 respectively. The best height of the growing layer to improve energy consumption was determined to be 25 cm and 20 cm. Annual energy savings reached 11.7 and 13.49 respectively.

The green roof in the climate of Wasit city is a practical and sustainable solution for energy consumption in hot and dry weather, and one can take advantage of its many advantages in the climate of the mentioned city.