Sunday, 27 June 2010

Suvarnabhumi International Airport Bangkok Innovative Climate Control System

Suvarnabhumi International Airport in Bangkok has come up with great architectural solutions to the problem of climate control. The challenge was a tough one for architects and engineers because Bangkok has an average temperature of 25 to 30 degrees Celsius and a relative humidity between 50% and 60%. In short, Bangkok is always hot and sweaty and the challenge was to design an airport with a cooling system that was both economical and energy efficient.

The first thing the architects did was to minimize the effects of solar loads. The terminal sheds on the north side are fitted with fritted glass with a 95% opacity specification that allow diffused light but minimize solar gain. On the hotter south side terminal sheds solid panels were placed on the roof to reduce solar gain to just 1%.

For the main spaces of the airport architects cleverly designed a zoned building. Thus there are no massive open spaces to cool. Instead cooling systems are directed at essential zones of the building. This prevents a lot of waste.

Two types of cooling system are deployed in Suvarnabhumi International Airport in Bangkok. They are radiant floor cooling which removes radiation striking the floor of the building; and secondly, an air displacement system with a controllable airstream supplying cool air to space at floor level and at low velocity. This is the genius part of the cooling system at the airport. It works on the principal of thermal air stratification. Namely, that cool air is heavier than warm air. So as long as you can prevent the floor heating up then much of the cool air that you pump into the building at ground level will remain cool. It is not necessary to keep the higher reaches of the airport building cool because nobody is at that level. The air heat is stratified so the air is kept at 24 degrees Celsius up to 2.5 meters above ground level and gradually gets warmer the higher up you go, until at roof level the air temperature is basically near ambient temperature.
Finally, the airport building uses an innovative three-ply membrane roof to allow in 1% to 2% diffused sunlight but prevent solar radiation. These membranes consist of Teflon-coated glass fiber, a coated inner membrane and transparent PC sheets on a steel cable and mesh structure. The inward facing side of the inner membrane also has low-e coatings to block solar radiation heat.

All in all, the architects and engineers at Suvarnabhumi International Airport in Bangkok have done a great job at energy efficiency for a very large and potentially difficult building to keep cool.