An approach to enhancing energy performance in residential buildings in hot climate regions (The case of Saudi Arabia)

Saudi Arabia, like many developing countries, is experiencing rapid urbanisation and infrastructure expansion, especially in the area of residential buildings. As an oil-producing nation with an extremely hot climate, the country is also renowned for high rates of energy consumption and carbon emissions. The construction sector is no exception, accounting for approximately 80% of total national electricity consumption, with residential cooling demand consuming almost 66% of domestic energy use. Although sustainability has now become a major focus for the Saudi government, with sustainable development being a key goal of the country’s economic and social development plan, the Saudi Vision 2030, the lack of energy efficiency in Saudi buildings has yet to be given serious consideration. However, with current demand threatening long-term energy security and forecasts indicating that domestic energy consumption will rise at a rate of 5% to 7% annually, it is crucial to improve the energy and environmental performance of the building stock. In order to support sustainable development within the Saudi residential sector, this study identifies the main causes of high energy consumption in the sector and the key barriers to enhancing building energy performance from a design and operational perspective, including environmental, economic and socio-cultural factors. It goes on to explore a number of possible solutions, assessing their effectiveness via simulation and calculating cost benefits in order to identify the optimal energy efficiency measures. These are then tested against local building regulations and benchmarked against international low-energy standards. The most effective measures are incorporated into a proposed framework for energy-efficient building design in the Saudi context, which takes local environmental, economic and socio-cultural factors into account. The framework covers both new builds and retro-fitting and constitutes one of the main contributions of this research. The study was performed in four stages, each utilising a specific methodology. Stage one involved an exploratory public survey, distributed electronically, designed to gauge public awareness of the benefits of sustainable building design and to identify design and operation factors causing energy consumption in residential buildings. Next, an existing family villa, representing a typical dwelling type in Saudi Arabia, was selected for modelling purposes and examined to identify design weaknesses. The third stage involved a consultation with experts in the field to assess current building issues and identify viable solutions in the local context. A model was then created using DesignBuilder simulation software, and its energy performance validated using data collected from the case study villa. Additional simulations targeting building design and operating parameters to enhance energy efficiency were also analysed to establish the optimal solutions within the local context. The use of surveys, a case study, and computer simulations to collect and validate the results is considered appropriate for the purposes of proposing energy strategies for residential buildings in hot climates. The findings indicate that much of the high energy consumption in the residential sector results from poor building design and construction techniques, inefficient operating practices, a lack of stakeholder engagement, and an absence of coordinated enforcement. However, the results of the simulations show that energy consumption and peak electricity demand could be reduced significantly by implementing the optimal strategies proposed in the framework. A potential reduction of 68% in total electricity consumption and 74% in peak electricity demand was shown to be possible, with an 81% reduction in cooling energy use intensity (EUI) bringing Saudi Arabia within the range of recommended European standards. Analysis of the improvement simulations also indicated that a reduction of 80% in carbon emissions was achieved in comparison with the base case study building. This amounted to almost 23 tonnes of CO₂ avoided annually and was equivalent to nearly five cars not being used per year. The cost-saving analysis employed to determine the economic viability of incorporating the proposed techniques indicated a typical payback period of 7 years, average annual savings of 1,603 USD, and total operational cost savings of up to 51% over a 30-year period. By incorporating the optimal sustainable design features, energy-efficiency measures, and renewable solar energy technologies proposed in the framework, the representative home was transformed into an energy-efficient structure. This study demonstrates that relatively simple strategies can significantly reduce residential energy demand in hot climate conditions and that the strategies in the proposed framework are effective. These findings have significant implications for building sector professionals, policy-makers and building occupants. A dramatic reduction in energy consumption would save costs, reduce CO₂ emissions, alleviate the need to increase power generation capacity, and enhance the country's profile internationally, resulting in significant environmental, economic, and social benefits. However, this cannot be achieved without support from the government, the housing industry; and the general public, so the study concludes by recommending further measures to support the development of a sustainable building sector in Saudi Arabia in line with the aims expressed in Vision 2030