Building the smart way

Thermal insulator: Water-based heat coating is available in the market for those looking for simple efforts to reduce heat absorption on the roof at a price starting from S$11 per square meter.

It’s another hot and humid day. The average temperature in tropical Asian cities keeps on rising, they say.

But, hey, we’ve always had a place to escape.

Hopping from air-conditioned homes to air-conditioned offices day in and day out, Asian urbanites have become sort of numb to the effects of global warming. Technology has allowed us to circumvent the impacts of climate in our everyday life.

For more than a decade, air-conditioned middle to high-rise buildings have acted as a getaway for people living in cities where temperature can rise up to 39 degrees Celsius during the day.

With scenarios of ever-rising global average temperatures, creating a pleasant concrete jungle for Asian city inhabitants has been the major challenge. Well, creating one in a smarter way that does not waste energy, that is.

Nowadays, architecture is no longer about postmodernism, deconstructivism, minimalism or any kind of “ism”.

If anything, today’s mantra for architecture has to do with becoming wiser in constructing our built environment.

And technological advancement has provided us with a richer array of building materials to accomplish just that, as recent green building material expo BEX Asia 2009 in Singapore reveals.

Twenty five percent of building’s interior heat comes from solar radiation, said Joachim Luther, the CEO of the Solar Energy Research Institute of Singapore.

Another 23 percent comes from lighting, 13 percent from glass conduction and 19 percent from ventilation. So, first and foremost, blocking sunrays is key to prevent heat from coming in.

While the passive design approach has been the standard approach, recent technological developments in building materials have also provided another way to prevent high rises from warming up, from glazed curtain walls to simple thermal insulator coating for our roofs.

“Single glazed windows only provide a thermal insulation ratio of between 5 and 7. Double the glazing and you’ll already cut it by half,” Luther said.

Harvesting energy: In a tropical country, the abundant sun rays can be turned into energy for a building’s internal use as industries have developed various scale of solar panels.

“If you go the extra mile with super triple glazing, it will go down to a tenth of the single one.”

Meanwhile, the current state-of-the-art for curtain walls is actually optical switching that works based on daylight sensors and room occupancy.

The technology relies on thin photochromic film mirrors that will automatically darken in sunlight to reduce solar heat gain. It obviously requires extra up-front investment of around 12 percent from business as usual, experts say, but it’s an investment that will pay up in the long-term by reducing energy bills.

There is another way to prevent heat from coming into buildings if the exterior surface is not a curtain wall: insulation. Yes, buildings in tropical climate countries can also be insulated, as opposed to the general view that insulation only applies to buildings designed in countries where the climate has four seasons.

Chemical companies such as German-based BASF have been focusing their innovative research on the choice of insulators. Made of more compact polystyrene granules, this kind of insulation can reduce energy consumption for cooling buildings down by up to 40 percent.

“As such, insulation is effective for energy-efficient construction,” Jessica Grove-Smith of the Passive House Institute said.

Initially, the construction business shelved the idea of using insulators in buildings because no matter how thin they are, they still take up space. But, nowadays, even that is no longer a problem.

“The conventional polystyrene insulator measuring 20 centimeters in width has already been replaced by a vacuum insulation only a tenth of that width. So, lack of space can no longer be used as an excuse for avoiding insulators,” Luther explained.

Smaller-scale buildings can be insulated with a thin layer of water-based acrylic applied on the roofs of homes and industrial workshops.

“So far, we’ve tried [insulation] in Australia between 2002 and 2004. During summer, the application of this layer can reduce the amount of energy used for air-conditioning by up to 47 percent,” said Chris Crawley, vice president of SkyCool, one of the companies offering such insulation products.

Shielding layer: Energy efficiency using thermal insulation can even be done at home with the widely available roof insulation products which can lead to additional space on the attic.

Applied on metal roofs of commercial and industrial buildings, this type of insulation reflects 85 percent of incident infra-red radiation. The extra investment of at least S$11 per square meter of application will pay back in just over two years from savings on energy bills.

Yet admittedly, even with the curtain wall glazing and wall-to-roof insulation, creating an agreeable temperature inside buildings still requires a cooling system.

Design-wise, using heat waste coming from building chillers has been the latest approach. But, the choice of what kind of technology to use is also crucial.

Combining several approaches — from reconfigured chiller units to precooled air handling units, Singapore’s Plaza at the Park has claimed a 23 percent reduction in energy use. With such a performance, its air-conditioning system related equipment will pay the extra investment back in six years.

The construction industry has always used cost as an excuse to settle for business-as-usual practices. But, we all know that everything comes at a cost.

It’s just a matter of choosing to pay it up front for long-term benefit or deal with it every month for the rest of a building’s lifetime. If vision is the mantra of building developers, then the choice should be obvious.

— Photos by Anissa S. Febrina