The Impact of Urban Form on Summer Time Air Temperature and Energy Demand: A Case Study at Dhaka, Bangladesh

Cities are experiencing intensified urban heat island effect and rising energy demand because of urbanization. Dhaka, Bangladesh, is such an example with heat stress and energy crisis. This study investigates the role of different elements of urban form (vegetation, water body, building height and built-up area) in reducing urban energy demand by mitigating the urban heat island effect. First, two study sites were selected based on their land use; second, ENVI-met, a Computational Fluid Dynamics (CFD) tool was used to calculate localized air temperature; Onsite measurement was collected from one site to evaluate the simulation result; lastly, the energy simulation software UMI was used to simulate daily and hourly building energy use. The study results showed that vegetation, water body and building height can reduce the air temperature which can reduce the building cooling load during summer. Most significant cooling effect was observed because of vegetation by 1.22 C (maximum), which lowered the daily cooling energy load by 2.5%. On the other hand significant heating effect was observed because of increased built-up area by 1.54 C (maximum), which increased the daily cooling energy load by 5.38%. This research aims to facilitate environment sensitive planning and design in Bangladesh.