Sustainable design strategy:assessment of the impact of design variables on energy consumption of office buildings in Abuja, Nigeria

摘要

Buildings account for about 40% of global energy consumption and contribute 30% of all CO2 emissions. This research project investigated extant office building development in Abuja, Nigeria with a view to establishing typical energy performances. Energy end uses were critically analysed to identify energy saving potentials. The research evaluated design variables that can be used to facilitate low energy building design and determine enhanced performances in the Nigerian and regional context.The research initially adopted a case study approach that involved fieldwork surveys and walk-through energy audits in which 22 office buildings were investigated belonging to four performance based categories developed for the research. Also, based on a building inventory survey form developed for this research, building information obtained included the buildings physical components, energy use management and energy end uses. This enabled typical energy performances of the office building categories to be deduced using three widely used indicators; the Energy Use Index (EUI), the Energy Cost Index (ECI) and the Carbon Emission Index (CEI). Also, disaggregated energy end use showed an average distribution pattern of air conditioning, lighting, equipment and building services in the ratio 59%, 15%, 43% and 4% respectively. This showed the potentials of energy savings by reducing cooling load.With the aid of computer based simulation (using IES-VE software) the research further evaluated the impacts of nine architectural design variables (identified from design guidance for low energy buildings as well as design recommendations for tropical climates) on building energy consumption using simplified models of the case study office building categories. From all these, an impact hierarchy of the design variables was deduced and the appropriate low energy design strategies were developed. This showed potential energy savings of up to 20% was achievable. Also benchmarks for enhanced building performance targets for all the categories were proposed for the furtherance of a sustainable built environment in a developing world context.