Impact of City Urban Patterns on Building Energy Use: Al-Ain City as a Case Study for Hot-Arid Climates

Architects frequently face problems in choosing the most appropriate solar orientation for a building due to the constraints imposed by urban grid patterns. Urban patterns are usually designed according to urban criteria that do not address issues such as orientation, building-cluster, solar access and loading. This problem causes thermal discomfort for building occupants in spaces oriented to west and east directions, resulting from radiant temperature, as well as higher use of cooling energy. The study focuses on the orientation, form (surface area) of the building and location and number of windows on the building elevations. An energy simulation program “ENERFACE” is used to analyze the selected buildings in Al-Ain City, UAE. The cooling energy utilized per m² and the total energies use as a result of different orientations were reported. Results show how the urban patterns could provide a better guide for architects to control the energy use in buildings. On the design level, the study concludes that the total annual energy use (kWh/fear) and the annual cost/m² could be minimized when the location of windows are kept only on two elevations of the building and the relative orientation of these elevations is 60° North-East. This reduction is about 55%.