The Impact of Modified Residential Morphologies on the Outdoor Microclimate in Hot and Dry City of Erbil, Kurdistan-Iraq

Abstract

In 1991, the Iraqi Kurds established an autonomous state of Iraqi Kurdistan. Erbil, the state’s capital, rapid expansion has moved away from using the principles of design in a hot dry climate. This organic morphology has been superseded by a modern grid-iron (MGI) planning grid to accommodate motor vehicles. The alignment of these MGI has been driven by geometry rather than referencing urban microclimatic needs and has increased energy demands. This paper uses ENVI-met to predict microclimate in the MGI urban pattern of Erbil, focusing on the prediction of dry-bulb temperature (T), mean radiant temperature (MRT) and wind speed (WS). These predictions were compared to weather stations located in the urban development of Erbil, in common with other researchers; good agreement was achieved during the day time, less so during the night time. Using ENVI-met, the orientation and street canyon widths have been investigated to achieve the highest WS around buildings. These higher WS can be utilised to increase natural ventilation of buildings, this will decrease the need for mechanical cooling leading to a reduction in energy consumption. With low rainfall and limited water service provision, a blue/green environmental strategy was not possible, and due to limited possibilities to manipulate the urban street canyons to provide shade, meant that the possibilities of reducing the T and the MRT were restricted. To reduce the MRT, the use of external shading mesh was explored. This reduces the Sky View Factor and, therefore, limits solar gain. The ENVI-met climatic model demonstrated a significant reduction in the MRT.