NUS' wall garden idea may keep buildings cool, green

March 14, 2007

NUS' wall garden idea may keep buildings cool, green

It is working with Japanese firm to develop technology for use in tropics

By Jessica Cheam


THIS little red dot is well on its way to looking - and being - rather green over the next few years.

The National University of Singapore (NUS) is studying how more plants can be grown on building walls here - to cool buildings down and save electricity too.

The project, which began earlier this year, is among four research proposals submitted by NUS to the Ministry of National Development for a share of its $50 million research and development fund for green technologies.

Launched in December last year, the fund attracted 62 proposals in the first wave of applications, said a Building and Construction Authority (BCA) spokesman.

There will be another window for applications in June.

Associate Professor Lee Siew Eang, director of NUS' Centre for Total Building Performance, said the siting of buildings close to one another in many areas here results in a lot of direct and diffused radiation of heat.

The temperature on roofs can go up to 50 deg C, heating the air around the buildings. This makes air-conditioners work harder and wastes energy.

'Greenery on the roof and walls will help absorb radiation and reduce the heat and temperature,' said Prof Lee.

NUS signed a two-year memorandum of understanding (MOU) last month with construction firm Shimizu Corporation, which has successfully developed a type of technology for vertical greenery in Japan.

The technology, called the Parabienta Green Wall, works by using a lightweight, 5cm-thick sponge-like sheet of polyester-blended soil heated with steam and moulded together.

It has good water retention and drainage properties. NUS is trying a number of tropical plants, such as the money plant, in this medium.

Shimizu and NUS are now developing the technology for use in the tropics.

Associate Professor Wong Nyuk Hien of NUS' department of building, who is spearheading the project, said: 'It's still in the early stages and we are conducting research on whether it will be viable for Singapore.'

He added: 'The main challenge now is to develop a system that is cheap and easy to maintain here.'

Other factors, such as effects of wind, impact of the vegetation on the walls and maintenance costs, will also be considered, he said.

The project fits in well with the Government's vision of Singapore as a 'city in a garden'.

Germany and Japan are the leaders in this technology at the moment, said Prof Wong. Similar research is being conducted by the National Parks Board and the BCA.

He added: 'This could certainly be a viable system for our HDB blocks.'

Last month, HDB announced a Housing In The Park theme for the rejuvenation of older estates.

The next-generation housing blocks that will emerge will have water- and electricity-saving features.

And sky gardens - green oases at the mid-levels of high-rise blocks - will be first seen in the upcoming 50-storey apartment buildings in Duxton Plain.

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CHALLENGE TO DEVELOP SUITABLE SYSTEM

'It's still in the early stages and we are conducting research on whether it will be viable for Singapore. The main challenge now is to develop a system that is cheap and easy to maintain here.'
ASSOCIATE PROFESSOR WONG NYUK HIEN of NUS' department of building


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