The 15-story building, formed of three connected towers, boasted a 50,000-square-meter "double-skin breathing" glass wall -- two panels of glass sandwiching a layer of air circulating between -- which was about 40 percent more energy efficient than a typical glass facade. The building's interlocking geometrical design, influenced by Chinese calligraphy, allowed for an expansive atrium and plenty of natural light. A large rooftop garden, irrigated with recycled water, provided a critical cooling effect.
The building was completed in 2006. When I toured the building last month, it wasn't merely to admire the design. The building already had undergone an energy efficient retrofit.
China is still putting up buildings at an astonishing pace, although perhaps slightly slower now than its peak a few years ago, when it was estimated that China built 2 billion square meters of building space -- the equivalent of every building in Canada -- each year. The World Bank estimated in 2010 that nearly half of all the buildings constructed in the world during the next two decades would be in China.
China's building sector accounts for more than 25 percent of China's energy use, and Chinese buildings are on track to become responsible for one-fifth of the world's coal consumption by 2020 -- stretching the limits of what China can supply. Improving the efficiency of its buildings, new and old, is a key part of China's strategy to reduce energy demand.
By 2020, 30 percent of new construction in China will be green buildings, according to the Ministry of Housing and Urban-Rural Development. Retrofitting existing buildings for energy efficiency is also an important strategy. There are already more than 40 billion square meters of building space on the ground in China (about five times as much as in the United States). The Chinese government has launched a program to retrofit homes in colder areas, and in its current five-year plan, aims to retrofit 4 million square meters of nonresidential building space in 10 cities, reducing each building's average energy consumption by 20 to 30 percent. That would be the equivalent of retrofitting 16 Empire State Buildings, one of the largest office buildings in the world.
The Chemsunny retrofit is an unusual case, given its recent construction and existing energy-saving features. But the building's owner, the state-run chemical giant SinoChem, was keen to set an example. They invested about $2.85 million in the retrofit, an investment expected to cut about 1,700 tons of global warming pollution while saving roughly $250,000 each year in energy costs. Older buildings, the typical targets for retrofits, probably would see quicker payback times. A recent retrofit of an office building in Nanjing, built in 1997, has an expected payback period of about 5.5 years.
Next page: The Chemsunny retrofit
Chemsunny World Trade Center courtesy of Franshion Properties Limited.