Energy efficient design of an office building: A case study

Botswana imports about 60% of its electric energy needs from ESKOM of South Africa. This figure is increasing as the energy demand in the country increases. Research has shown that about 20 to 40 per cent of electric energy in buildings is consumed in lighting, and about 30 to 50 per cent of the operating costs in buildings are associated with lighting. In this paper, possible methods of energy efficient lighting systems are considered. A 3-D computer generated design of a room is carried out to establish equal lighting effects of two lighting systems, conventional and efficient lighting design systems, but have different energy consumption. The design is implemented on a non - efficient lighting system. The investment costs as well as the energy costs of both the conventional and the efficient designs are compared, and a pay back period is calculated for the efficient design. The application of the proposed efficient design by engineers could be useful in reducing the energy consumption in the country, and hence reduce the importation of electric energy into Botswana.