Energy performance of low-rise residential buildings: optimisation of building envelope construction in different climate zones of the Kingdom of Saudi Arabia

The government of Saudi Arabia's energy policy seeks to reduce energy consumption by setting up National Energy Efficiency Program (NEEP) initiative and Saudi Energy Efficiency Centre (SEEC). The key focus of the SEEP initiative is directed toward buildings, industry, and transport. Notably, the first of these sectors makes up 23% of all the energy use in Saudi, with 80% used for building air conditioning purposes. Therefore, there is an urgency to improve the energy efficiency of the existing building stock and new build by adopting sustainable architectural approaches. This creates a need for more sustainable and energy-efficient building construction methods using passive energy techniques. The introduction of modern building processes and materials in the KSA, which often consist of concrete and prefabricated structures, has led building occupants to rely heavily on mechanical air conditioning for their thermal comfort. This is translated into huge power consumption bills and demands on the electricity infrastructure of the country, particularly in the summer months. Therefore, this project aims to investigate and carry out a comparative study of building construction materials, passive design methods and energy performance in selected regions of the KSA as defined in the Saudi construction code for their distinct climate. With the aid of a commercial software package, Design Builder, a computer model of a typical Saudi private domestic building (known as type A villa) selected from the Ministry of Housing residential construction projects was developed. The baseline energy performance of the selected building was obtained both from energy bills data from the Saudi electricity company and established through computer simulation based on the current Saudi construction code for different regions. The computer simulation of the energy performance of the case building was validated using three-year average energy data from bills. The measured annual average power consumption of the case building was 61198.33 kWh (249.789 kWh/m2 of floor area), whereas simulated energy consumption was 61223.82 kW (249.893 kWh/m2), a root mean square (RMS) average difference of 9.761%. Similarly, the computer simulation results showed that by adopting higher passive construction standards in the Saudi construction code, energy savings of over 20% could be accrued depending on the type of construction intervention and region of the country. For example, the computer simulation analysis demonstrated that improving wall insulation level from on the current standard using Wall 08 type, which consists of a double concrete block wall with rock wool board, can save on average 12.74% of the electricity consumption of a household. Equally, other passive techniques such as shading devices, green roofs, and glazing showed an incremental reduction in energy consumption. This study demonstrated that there is scope to improve the Saudi construction code by bringing in tighter passive construction strategies such as higher insulation level of the external envelope to reduce the energy consumption of buildings and improve occupants’ thermal comfort.