Effect of courtyard height and proportions on energy performance of multi-storey air-conditioned desert buildings

Courtyard buildings have been always recommended as a passive architectural technique in desert environments in order to maintain indoor thermal comfort. Nowadays, an increasing number of buildings are air-conditioned. The importance of using passive techniques, then, becomes to reduce energy consumption. A previous study, however, showed that in desert environments, the energy performance of two-storey residential courtyard buildings proved less efficient than other solid forms, even when attached to neighbouring buildings from three sides in a compact urban fabric. Their performance was relatively better in mild desert climates than in extreme hot ones. The study was limited to a single family house with “thin” depth of zones surrounding the courtyard. In multi-storey courtyard buildings, the courtyard results in more height and self-shading on the facades overlooking the courtyard. This will have a direct effect on the energy consumed for cooling and heating, as well as on that consumed by artificial lighting This study questions the effect of courtyard height proportions and thickness of the built area surrounding it on the energy consumption in multi-storey air-conditioned courtyard buildings and tracks that effect under different desert climates. Courtyard buildings of 1-10storey-height were modelled using the DesignBuilder software and simulated using EnergyPlus simulation engine for the desert climates of Khargah, Cairo, Alexandria and for the temperate climate of Berlin for comparison. All cases were compared to the corresponding solid building forms of the same built area. Air-conditioned courtyard houses has not shown a significant improvement in energy savings in desert environments, buildings with bigger depth surrounding the courtyard had a much better performance than thinner buildings, giving small energy savings with building depth exceeding 12m.