HARNESSING PASSIVE COOLING STRATEGIES TO ENHANCE THERMAL COMFORT IN THE DESIGN OF PROPOSED SCHOOL OF ENVIRONMENTAL STUDIES ABDUGUSAU POLYTECHNIC ZAMFARA STATE, NIGERIA

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Department of Environmental Design

ABSTRACT
Passive design responds to local climate and site conditions in order to maximise the comfort and health of building users while minimising energy use. The key to designing a passive building is to take best advantage of the local climate. Passive cooling refers to any technologies or design features adopted to reduce the temperature of buildings without the need for power consumption. Consequently, Buildings consume large amount of energy in order to achieve thermal comfort for users. To achieve the goal of thermal comfort in buildings, passive cooling is one of the suggested practices emphasized to be adopted in many buildings around the world of which educational facilities have been a major target as an opportunity of achieving thermal comfort. When it comes to educational facilities, end users who are usually students, lecturers and other occupants spend almost 50% of the entire day within the buildings. To add on 50%, occupancy is predominantly during day time when environmental conditions are adverse to human survival hence creating thermal discomfort which in turn leads to low productivity and occupancy dissatisfaction. Many educational facilities mostly in Africa have been built relying on natural climatic conditions for occupancy comfort throughout the year which has brought about discrepancies amongst users. Whilst passive cooling can provide thermal comfort in some climates, a gap of thermal comfort improvement strategies in buildings still exits to enhance suitable thermal condition in buildings thus avoiding occupant dissatisfaction, low productivity and overall building performance. The aim of this study is to test the usefulness of applying selected passive cooling strategies to improve thermal comfort of buildings in hot dry climate of Gusau for the design of School of Environmental Studies Abdugusau Polytechnic, Nigeria. The methodology adopted were case studies and simulation whereby, three 3 case studies vii buildings of the same usage type were selected and eight passive cooling strategies were applied. Simulation software – namely ECOTECT – was used to assess the performance of the building. Solar shading performance was also assessed using Sun Cast Analysis, as a part of the ECOTECT software. Result from the simulation indicated that the Mean Radiant Temperature can be reduced and thermal comfort percent can be improved by applying passive cooling strategies. Mechanical ventilation without cooling registered a negligible improvement in occupancy thermal comfort while on application of scheduled cooling thermal comfort improved between slightly warm and slightly cool with a 15% improvement in comfort hours. Also, in respect to indoor temperature, upper rooms are the worse where the temperature reach up to 39°C on peak day hours beside the temperature drop to uncomfortable level during night, the situation is different on ground flat when simulation indicated better performance on ground floor even though the recorded temperature still above the comfort level but not as high as those recorded on top floor. Also the simulation showed that temperature at peak hour (between13:00 and 17:00 O’clock) up to 40°C which is almost 12°C above comfort range. This means that it is impossible to achieve comfort temperature with passive cooling however passive cooling improve significantly temperature within the building. This study can help architects and related stake holders to exploit passive instruments to reduce interior temperature and energy consumption of a building during the design process.