Atrium Form and Thermal Performance of Middle-Rise Wide Span Building in Tropics

Energy use of a building usually increases as long as an increase of the surface area of the envelope. Heat transfer of the building through the envelope can be reduced by perfect design. Right building form and materials can reduce the heat transfer. Middle rise building has a quite high surface area of the roof, and in a tropical country, roof accepts the highest irradiance thus bring much heat to the building. In the same volume, compact building form is better in thermal performance, but large building usually need an atrium to help the natural lighting in the room. The atrium uses transparent roof or skylight. This transparent roof definitely can increase the heat gain to the building significantly. So this research aims to find the best form of atrium roof in middle-rise and large span building in the tropical region. This research aims to analyse the thermal performance of middle-rise and large span buildings and its relation to the form of the atrium. A sample of middle-rise office buildings in Surabaya was taken randomly. The simulation was conducted to predict thermal and cooling energy performance. Energy performance of the building was found to bear some relations to form of roof.