Investigating the role of façade design in improving energy efficiency for residential tall buildings in Saudi Arabia

In Saudi Arabia, 53% of the primary energy is consumed in the residential sector due to the significant use of air conditioning to cool the indoor spaces. Moreover, actively conditioned tall building poses many environmental challenges as major contributors to CO2 emissions arising from the combustion of fossil based fuels. Despite the efforts reflecting the government’s growing concern about domestic energy consumption, the scattered conservation efforts have been largely ineffective. As for the local building codes, the typical approach deals only with the minimum requirements of the ‘engineering parameters’ of building envelope (e.g. adjusting glazing and wall properties, thermal transmittance values), without addressing the façade’s ‘architectural design parameters’ such as shading devices and intelligent use of transparency and opacity, that interact with the building design and have an impact on performance of the building. In this paper, the authors explored the hypothesis that the current approach focussing on the façade’s engineering parameters is not sufficient to achieve the necessary energy efficiency in residential tall buildings in the hot climate of Saudi Arabia, and architectural design parameters, which are less common in their application in the region, could be explored to reduce cooling loads. In order to investigate this hypothesis, the current architectural characteristics of residential tall buildings in the region were identified to establish a representative hypothetical base case in the city of Jeddah, and then 27 sets of dynamic thermal simulations were compared. The best and worst combinations of glazing ratio, wall and glazing type were identified in order to understand the most influential parameter impacting the cooling energy loads in the building. The findings suggest that the difference between the best case and worst case build up ranges between 92 and 128%, outlining the huge role even simple facade design changes can make in terms of energy performance. The work aims to contribute to the effectiveness and potential enhancement of building codes and regulations for residential tall buildings in Saudi Arabia, especially in terms of energy efficiency measures and benchmarks, and the quality of indoor environment for this building type.