Eco-town in the making
Singapore boasts of several impressive green buildings.
WHAT could be more pertinent on an island state such as Singapore than affordable housing when space is a major constraint? Ever since the idea of HDB (Housing And Development Board) flats was mooted, and then executed, Singapore has managed to solve its squatter problem, and as Lau Joo Ming, managing director of the HDB Building Research Institute, said, “People were more properly housed.”
Taking things a step further in the direction of sustainability, Punggol, a northern coastal town, has been earmarked for a “green makeover.” The former fishing village is to serve as a “living laboratory” to test innovative green technologies which would then be introduced to other towns.
In fact, HDB had already implemented its first green housing project there, Treelodge@Punggol, before plans for an eco-town were announced. Treelodge@Punggol utilised solar panels and rainwater harvesting.
To make Punggol – which has two rivers running through it – Singapore’s very first eco-town, a waterway that traverses the town was built. Completely self-sustainable, Punggol will have small individual estates sharing common green with an integrated public transport system, including an MRT line that runs around the town and also to other parts of Singapore. To promote clean commuting, cycling lanes will be built, as well as charging stations for electric cars.
“We designed Punggol a bit different from the other towns,” said Lau. “We try to have common green more accessible to the residents. All the green is connected and also connected to the waterway. And because Punggol is a coastal town, we try to keep to a seashell theme.”
So far, 15,000 of these eco-living units have been completed, and HDB expects to complete another 20,000 by next year. Lau said LED lighting will also be used. LED lights, he said, use only 10 watts, which means a big energy saving.
Lau said HDB, being a big developer, is able to sponsor the technology and also lower the cost, while also helping to build up the capabilities of the suppliers and the engineers. The Housing and Development Ministry and the Environment Ministry estimated that Singapore should reduce its carbon emissions by 15%.
Some 3.2megawatt of solar energy will be generated to supply the flats. “We work with researchers and our energy authority to pump the energy straight into the grid and eliminate the use of batteries. When implementing solar energy, your main cost is batteries,” said Lau.
Read in comfort
The first thing you notice as you step into the premises of the Singapore National Library is how much natural light there is. There is almost no need for artificial lighting in the daytime.
The building on Victoria Street was designed and built with an orientation away from the east-west path of the sun to prevent heat build-up and the stack effect of an open plaza takes full advantage of the wind and natural ventilation. This is evident in how windy and cool the open plaza area right outside the front entrance is, and students and other visitors can always be seen sitting around enjoying the natural comfort.
The daytime brightness inside the building is helped by well-placed light shelves incorporated into the architecture of the building. The surface of these light shelves reflect daylight onto the ceiling which in turn reflects light further into the interiors. The large glass windows also have blinds that are linked to light sensors. When the light measurement is above 8,000 lux, the blinds will be automatically lowered to prevent glare. Low-- emissive double-glazing glass is also used for the windows.
Energy efficiency is further helped by motion sensors in the restrooms where the lights turn on only when they are being used. The escalators are in start/stop mode using pressure sensors. When not in use, they do not just slow down but stop completely. The floor directory is arranged in such a way as to encourage people to use the stairs and escalators more than the lifts.
There is also no shortage of green around the building. At mid-day, visitors can be seen sitting around using their portable computers in the airy and shady roof garden on the fourth floor. And if it rains, rain sensors would stop irrigation for up to eight hours after a downpour.
The National Library was given the Green Mark Platinum Award (the highest ranking in Singapore’s green building certification scheme) in 2005, and two years later, it won first prize in the Asean Energy Efficiency Awards.
The mall goes green
The 313@Somerset shopping mall’s green initiatives involve not just the building management but also the 177 tenants operating the various stores and food outlets. Apart from the use of solar panels on the roof for renewable energy, light sensors, escalators that slow down when not in use, rainwater harvesting and other such green measures, the tenants’ collaboration is equally needed.
As such there are Green Lease conditions with which every tenant has to comply. These guidelines involve the use of energy-efficient light and power equipment, waste management and recycling practices, among other things. Tools such as the Retail Services Calculator are provided to tenants to calculate lighting loads and energy consumption. Their energy use are monitored and incentives are given for energy-efficiency.
There are designated parking spaces for electric cars on the rooftop carpark, the integrated design of which acts as a natural heat shield. And in the future, free charging stations will also be provided.
The 313@Somerset project also won the Green Mark Platinum award, plus the Solar Pioneer Award under the Economic Development Board’s Solar Capability Scheme.
Other Singaporean constructions built with green in mind include the solar-powered Poh Ern Shih Temple and the Samwoh Eco Green Building where one floor was constructed with 100% recycled concrete aggregate.
IN Rome, the famous ancient building called the Pantheon is almost 2,000 years old. Yet the structure stands as it did two millennia ago. In fact, the dome is still recognised as the world’s largest unreinforced concrete dome. The structure is made from Roman concrete which often used not just lime and gypsum as binders, but also the much-preferred pozzolana, or volcanic sand.
“If that building were made from normal cement, it would have collapsed already,” said Matthias Gelber, co-founder of Maleki Green Building Products which is based in Malaysia.
“Conventional cement gets attacked by the chloride in the air,” said Gelber, who spoke on
Green And Sustainable Construction at Singapore Green Building Council’s Green Building Conference last month. “Normal cement cannot take acidic environments. It has calcium hydroxide (CaOH), which gets attacked by chloride or acids. The Pantheon was made from volcanic ash. The Romans bonded volcanic ash with lime.”
Building materials is a big culprit in climate change. The production of cement involves the breaking down of limestone into calcium oxide, and the process requires very high temperatures, up to 1,350°C. When limestone decomposes to calcium oxide, 60% of its mass is released into the air as carbon dioxide.
Gelber’s company is producing a type of “green cement” using recycled by-products from industrial processes. Some industrial waste materials contain calcium oxide and other primary components of cement, but it is difficult to activate them. Maleki has developed an eco-binder system that can activate these materials without releasing CO2 in the process, while improving on the cement’s acid resistance and curing time.
Using materials that would otherwise end up in landfills eliminates the need to tap into natural resources. Maleki co-founder Hossein Maleki started by researching how to use fly ash from the Frankfurt municipal waste incinerator to replace cement.
“Normally, for green concrete, its strength is less,” Gelber explained. “That’s why build- ers are worried about green concrete. But we can increase the strength of our green concrete, and we can make extremely strong concrete.”
Another advantage of green concrete is that the material’s high strength does not come at the price of heat generation. Gelber cited the example of the Petronas Twin Towers, where during its construction, an inordinate amount of ice was needed to cool the high-strength concrete foundation needed for the heavy towers. The different bonding system developed by Maleki ensures that such heat generation does not occur.
“And normally, cement is made from limestone which is calcium carbonate (CaCO3),” Gelber added. “When we burn limestone, we need a lot of fuel, such as coal. So we get a lot of CO2 emission from the burning of the coal. The limestone has absorbed CO2 over millions of years, and we release it when we burn it. For one tonne of cement, we get one tonne of CO2 going up into the air.”
So a cement plant that produces 1,000 tonnes a day also generates 1,000 tonnes of carbon dioxide that pollutes the environment and contributes to global warming, said Gelber.
But he lamented that the building industry is still slow to embrace green building products, and still look for products with low prices.
“Cement companies have huge production kilns and they want to have returns on such investments. They are not keen on shifting radically to alternatives.”
Building green has clear advantages, but many of the benefits – such as energy-saving and increase in workers’ productivity due to a cleaner, greener workplace – can only be seen in the long-term. Most in the industry would rather opt for cheaper materials and lower their costs in the short-term.
He added that in general, companies are pro-active if the tax incentives from the green building certification are attractive. But the mechanics of that, and how it works in practice, still need to be sorted out. “Sometimes we get too sidetracked,” said Gelber, who is also a very active environmentalist. “We need to see things holistically. We need to build green communities. We need to change people’s mindsets, we need to inspire and educate people.”
Connected green: At Punggol Eco-Town, the
elements of nature will be harnessed in line with the concept of ‘green living by the waters.’
A roof garden helps keep the Singapore National Library cool while sun shades and light shelves provide plenty of natural lighting.
Big imprint: Producing the cement that is used in construction emits high amounts of carbon.