Building Configuration
The building envelope for this building will to be constructed from clear glazing and Teflon materials. The roof of the main terminal and parts of the concourses are shaded or partially shaded by roof shading devices. However, a majority of the concourses have no external shading devices. Teflon does provide a sufficient barrier for direct solar, but the glazing offers very little solar resistance. The thermal resistance of both Teflon and glass are relatively low and the conductive heat gain to the space would be enormous if a traditional indoor temperature of 24 °C have to be maintained. Using a variable air volume system traditionally employed at most large airports necessitates large volumes of air being supplied to the space maintaining the required temperature requires temperature. However due to the large volumes to the spaces creating a well mixed flow and no stratification. Air conditioning systems must supply volumes of conditioned air to a room in order to maintain conditions within specified limits. The environment requirements for a building can usually be met by different air conditioning systems. But it is easier to achieve the required results within given economical constraints with a variable system. The variable air volume system, varies the air volume being supplied to the space in accordance to the required conditions. By varying the air flow instead of constant air flow, the consumption of energy can be reduced. The air flow to the various zones are individually reset when the loads change. The maximum air flow is not normally required in all zones. simultaneously. Although the air supply system is designed for maximum operation. These systems can consume considerable amounts of energy most of which is consumed conditioning unoccupied space. During April, the warmest month, ambient temperatures vary from 34-36 °C. The temperature difference across the building envelope would be 10-12k. A variable volume displacement system was designed to maintain the required temperatures in the occupied zone (24C). Stratification would be enhanced by this system so that temperatures on the inside of the building envelope would be nearly equal to the ambient conditions virtually eliminating the convective heat gain to the spaces. The variable volume displacement system design and evaluation has been reported by Simmonds (1995,1996).