Published April 22, 2008


Nuts and bolts of green buildings

A perfect orientation is best but architects can also use other means to reduce energy consumption, reports MATTHEW PHAN

IT IS hard to pin down exactly what green architecture entails. Each building is a case study in itself, with specific surroundings, usage patterns, client requirements and weather conditions. One might use a north-south alignment to block off the sun's heat. Another, forced by circumstance to face the rising or setting sun, might use glazing or shades to achieve the same. Light and temperature controls for a residential apartment block differ from those for retail malls or industrial facilities. Still, certain principles run throughout.

Going green: City Square Mall's glass facade uses double-glazed low-emission glass to mitigate excessive heat and glare, plus an automatic sun-screen that will come down in the afternoon and rise back up in the evening

Architects approach a design in two ways - passive and active. 'If you have the passive side right, half the battle is won. Then you actively use technology to manage the things you couldn't solve with the passive approach', says Tang Kok Thye, senior principal architect at ADDP Architects.

Passive refers to elements like site layout, the facing of a building and how it is structured to allow for natural lighting and ventilation. Active refers to add-ons, like special glass to keep out heat and glare, solar panels or green roofing and the building's mechanical and electrical (M&E) guts.

Because air-conditioning is typically the largest user of energy in a building, the biggest energy savings come from temperature control. In a local context, this means figuring out how to stop a building from getting too hot. The right orientation is critical. 'If a building is facing east-west, a lot of money is spent just to make it comfortable to live in', says Mr Tang. Site layout and surroundings are also important. A building next to the sea or a park is cooler than one standing next to another building that might reflect heat and light.

In the early stages of design, architects often simulate how the sunlight and wind might flow into a structure, us