Singapore is an ideal testing ground for alternative energy, particularly within the built environment. The 277-square-mile city-state is home to more than 5 million residents, and relies heavily on imports, including most of the energy it uses, having positioned its economy around the low-footprint, high-output finance and technology sectors. Already, Singapore has shifted its reliance on oil-fired steam turbine plants to combined-cycle gas turbine facilities. And it has begun expanding its use of solar photovoltaics (PVs) due to the relative cost difference of importing conventional fossil fuel-based power-generation technology. A major area of emphasis for Singapore’s sustainability initiatives, and of perhaps the most interest to ARCHITECT, however, is the greening of its new and existing building stock.
A walk through Singapore’s downtown business district offers striking evidence of this initiative. Lush greenery springs from building façades, while large awnings shade entrances and walkways. Solar and wind-capture technologies are discretely incorporated into the envelopes of buildings situated to allow passive ventilation, while shading and the integration of living plants mitigates solar heat gain. (Singapore is one degree north of the equator.) Elsewhere on the island, greenery lines winding parkways and is strategically interspersed among the miles of mostly public, high-rise housing that serves Singapore’s growing population. (That growth has been stilted somewhat by the slowdown among the sizable non-permanent-resident population.)
On invitation from Singapore’s Building and Construction Authority (BCA)—a government agency that manages the country's construction industry—ARCHITECT joined a handful of U.S.-based media outlets earlier this month to explore a handful of such buildings and check out the products, installations, and control systems that have helped the island city-state become a leader in sustainable design and construction.
One way Singapore has done so is through the BCA's Green Mark building certification program, which launched in 2005 in the spirit of the U.S. Green Building Council's LEED program, but is tailored to projects in the tropics and sub-tropics, with emphasis on strategic site orientation, daylighting, and efficient mechanical air cooling. The government-led standard has since expanded throughout the region to include projects in neighboring Malaysia, Indonesia, and China, a push driven largely by Singapore-based developers working in those areas. The standard offers criteria for new and existing buildings, including specific use-cases such as data centers and supermarkets, as well as parks and other infrastructure. The BCA hopes to reduce the carbon intensity of Singapore's building stock by 36 percent between 2005 and 2030 while constructing or retrofitting its building inventory such that 80 percent of it meets Green Mark minimum standards. Building owners in Singapore are required to submit building performance and energy consumption data to the BCA annually. And, since 2008, new as well as existing buildings undergoing a significant renovation must meet the minimum Green Mark building standards.
With much of Singapore’s building stock subject to these criteria, there were plenty of examples of green construction for the BCA to show off. Our tour, however, included a handful of high-profile projects that incorporated international architecture firms and clients, and that show some of the more envelope-pushing examples of sustainable solutions and their measurable impacts on the buildings and their surrounding environments.
Zero-Energy Building at the BCA Academy
We began our tour at the BCA Academy, where the BCA holds its training courses for students, from roughly high-school age on up, in the building trades with an emphasis on green technologies. On the campus is a three-story, 48,438-square-foot structure that was built in 1984 and retrofitted in 2009 by local firm DP Architects to be net-zero energy. Today, it houses BCA offices, classrooms, and a resource center. It also serves as a living lab for exploring green technologies that the BCA is incorporating or hopes to incorporate in its own development. The staff showed us how design strategies such as shading devices, living walls, personalized ventilation, solar chimneys, displacement cooling, natural lighting, and mirror ducts were used to moderate the environment and manage energy consumption. Additionally, a rooftop PV array generates approximately 207,000 kilowatt-hours annually.
Our visit to the 40-story, 2014 office tower designed by Toyo Ito & Associates included stops at the rooftop garden and sky terraces, where flora native to the tropical region meets the criteria established in Green Mark’s Greenery Provision, which awards points toward certification based on how much of the 3D volume is covered by plants. The building is topped with a sculptural, conical white and red funnel (shown above) whose protruding petals capture and guide the prevailing winds down into the building’s air-cooling system. Meanwhile, a double-skin façade encases the building; it comprises a double-glazed, full-height envelope glazing shrouded by an outer shell of frame-less glass to reduce solar heat gain. The air cavity between the two glazing systems acts as a greenhouse of sorts for the plants, which clad more than half of the building’s façade and are irrigated by captured rainwater. The terraces and rooftop gardens double as outdoor gathering spaces.
National Gallery Singapore
French firm Studio Milou conceived of the design for this building, which opened last year and brings together two national monuments—Singapore’s former Supreme Court (1939) and City Hall (1929) buildings—into a new structure housing the largest public modern art collection in Southeast Asia. A glass canopy with aluminum screens cut to emulate rattan bridges the two original buildings and filters sunlight to create a cool, daylit atrium (shown above). Elsewhere, a few inches of water pool atop a glass roof to diffuse the intensity of the sunlight (show below), and is situated next to a solar PV system that generates 43 megawatt-hours annually—both installations are in view of a rooftop restaurant and are flanked by pedestrian pathways. Drip irrigation keeps the lush rooftop greenery alive, while a chiller system cools the building efficiently.
Marina Bay Sands
To understand this massive complex, which includes a hotel, shopping mall, casino, events center, and Mass Rapid Transit station (Singapore’s subway), we hit the rooftop before heading underground to see the control center. Designed by Moshe Safdie, Hon. FAIA, for the Las Vegas Sands Corp. and completed in 2011, it is the flagship development of Singapore’s Marina District, an extension of its downtown business core. Due to the expanse of the project, its building management system has more than 80,000 control points monitoring features such as overhead lighting and heating and water supplies. An expansive glass façade proffers daylight while photo-sensors within the building adjust the electric light levels. A district cooling system distributes chilled water along common service tunnels; additionally, the air-conditioning system utilizes water-cooled chillers that, the building’s management team says, are 80 percent more efficient than peer air-cooled models. Anaerobic digesters manage food waste, while an outdoor herb garden supplies the on-site restaurants. Atop the building, 133,473 square feet of greenery reduces solar heat gain, taking a load off of the building systems, while a rooftop “infinity pool” reflects sunlight and offers impressive views of the island and bay.
Gardens by the Bay
Visible from the Marina Bay Sands’ hotel rooftop is nearly 250 acres of infill parkland that extend into the bay. British firm Wilkinson Eyre Architects led the project's design, which was completed in 2012 and features two conservatories and a forest of "Supertrees” (shown above), or man-made structures designed to emulate the biological behavior of trees on a site populated by gardens featuring indigenous plants. The cool, dry Flower Dome and the cool, moist Cloud Forest (which includes a multi-story waterfall, top image) emulate the Mediterranean and Tropical Montane regions, respectively. They are housed in distinct steel-grid structures (shown below) that are free of columns to limit shadowing while the glass canopy lets light pass through. Outside, 18 Supertrees, each spanning 82 to 164 feet in height, incorporate technologies such as PVs, cooling channels in their structure to moderate the surrounding environment, and a skin of living plants that uses the tree structure as a trellis. Visitors can traverse the biodomes’ interiors and, if heights aren’t a deterrent, scale a catwalk connecting the massive tree-like installations.