Woo Sian Boon Today Online 26 Dec 13;
SINGAPORE — Residents of the future Marina South precinct — one of three new residential precincts unveiled in the Urban Redevelopment Authority’s (URA) draft master plan last month — may find walking literally a breeze and may also end up with greater energy savings as a result.
The authorities are looking to harness wind as a natural way to cool the entire district, which is located east of Marina Bay. This includes aligning major arterial roads — such as Marina Gardens Drive — in the precinct to the prevailing winds Singapore receives during different monsoon periods, to create “wind corridors”.
During the first half of the year between December to March, north-east monsoon winds will be funnelled into the area, while winds from the southwest monsoon will be channelled from June to September. The URA will also stipulate that future buildings in Marina South have varying heights — to a maximum of 160m — to create a “wind downwash effect” that will channel air downwards to pedestrian levels, with each building located more than 30m apart for better ventilation.
Said a URA spokesperson: “As a green field site in Marina Bay, Marina South presents an opportunity to adopt sustainable urban design principles. One of these strategies is to facilitate better wind flow for enhanced air movement to create a lower ambient temperature and improve pedestrian comfort at street level.”
The precinct will also boast buildings that are 30 per cent more energy-efficient than those in other areas, “extensive greenery and open spaces” to help reduce heat build-up.
Development will begin after 2017 and 9,000 private housing units have been planned for the 21.5ha of land. To arrive at these planning principles, URA had worked with the National University of Singapore (NUS)’s School of Design and Environment to study urban forms and how varying building typologies can better channel air movement.
The concept of harnessing wind movement to facilitate air movement and maximise ventilation is not new and has been implemented in public housing estates. For example, void decks located below Housing and Development Board flats and the distance between blocks provide “porosity” for air movement.
“At the same time, building blocks are usually oriented to take advantage of the prevailing wind direction to allow for natural ventilation of individual units and reduce the reliance on mechanical air-conditioning,” said the URA spokesperson.
NUS Department of Real Estate Associate Professor Tay Kah-Poh noted that for private housing, some property developers conduct their own wind studies before development, and that eco-friendly and sustainable design is “increasingly embedded” in urban developments. “Usually, they try to rely on natural ventilation as much as possible and less on mechanical means of cooling,” he said.
Associate Professor Ng Wai Keen from NUS School of Design and Environment’s Department of Architecture said: “Early HDB (flats), with the slab block/common corridor design, also facilitated natural cross ventilation. However, in the more recent configurations, this has been lost. So, attempting to recover this aspect is certainly welcome, and will help to reduce dependency on air-condition systems.”
Lower outdoor temperatures can influence how much energy is used to cool buildings, pointed out Professor Wong Nyuk Hien from the NUS School of Design and Environment’s Department of Building. He said: “Studies have shown that typically for one degree drop in the air temperature, the reduction of cooling energy consumption can be about 5 per cent. Though it seems small, but when you multiply the number of buildings in a typical township or district, the total energy savings could be tremendous.”
But besides the “clever” placement of buildings, researcher Marcel Bruelisauer at the Future Cities Laboratory’s Low Exergy Module added that further factors such as building form, facade openings and floor layouts need to be considered as well.
“(These) heavily influence whether or not building users can benefit from sufficient cross-ventilation, making air-conditioning unnecessary,” Mr Bruelisauer said. His fellow researchers Maria Papadopoulou and Didier Vernay added that the neighbourhoods and buildings can be designed in a way that allows the wind to carry away trapped heat from air-conditioners’ condensing units to reduce electricity bills.
Meanwhile, the HDB has also conducted wind simulation studies for new towns such as Punggol and Bidadari. Said the URA spokesperson: “Going forward, agencies will take the opportunity to improve air flow through such simulations when planning for larger precincts.”
Woo Sian Boon Today Online 26 Dec 13;