ABSTRACT
In commercial buildings, two-thirds of the sale time is during the day, it provides opportunity for optimizing the daylight potential of the region and reducing electric consumption. This solves the two key problems in shopping malls; these are visual and thermal discomfort of workers and customers. The current population growth and scarcity of land in Kano triggered the adaptation of vertical mall, which has a higher height ratio in relation to its area. Most of the shopping malls lack one of the two important key areas which are thermal and visual comfort, therefore the need to optimise these two key elements in design and hence the problem of this study. The aim of the study is to design a vertical shopping mall that optimises daylighting using vertical light pipes (VLP) in Kano. A careful study of the literature reveals that the above is only possible using experimental research design as it is the best to test the efficiency of light pipes in buildings. The methodology adopted for the study was an in depth literature review, case study and experimental research design with simulation as a tool. The major factor considered in the simulation was illuminance within a 3m x3m x 3m windowless box, to investigate the efficiency of dual technology of light pipes and light rods with an increase in diameter as well as in length. The results show that inclusion of vertical light pipes in a space showed a 20% increase in daylighting in that space and that the illuminance within a space reduces by 6% in every 1.5m length. It was concluded that vertical light pipes transfer uniform light to places other daylight apertures cannot reach, while excluding heat and glare. It implies that using light pipes in a shopping mall reduces the cost of lighting the interior and reduces the cost of cooling. Due to the width of a space in a shopping mall, side light and exterior toplight is inadequate to provide daylight within the space. As daylight travels in a straight path, the shelves and merchandise provided within a space obstructs its transfer deeper into a space. Orientation determines the shading to vii be provided for sidelight apertures to further exclude glare from reaching interior of a shopping mall. The fenestration material used also determines the quality and quantity of daylighting within the space. Light pipes transfer more daylighting to lower floors than other toplighting strategies like skylights. Finally, this study could be said to have achieved its objectives and answers its research questions. Furthermore, some recommendations are given as follows; Based on the simulation results, it is recommended that vertical light pipe should not exceed a height of 9.5m for effective and efficient light transmission. Although vertical light pipes improved the interior daylight up to 20%, it cannot be used on its own. Other daylight strategies should also be considered during the design stage of any project.