Green buildings: Expo 2010 in Shanghai, China

Expo 2010 in Shanghai, China is on, and is expected to draw 70 million visitors. With a theme of "Better City, Better Life", it aims to explore the full potential of urban life in the 21st century and how to create an eco-friendly society. Japan's purple solar powered pavilion is attracting a lot of attention. Its Chinese nickname is Zi Can Dao, meaning "purple silkworm island." Covering approximately 3900 m², it features the world's first pillow membrane with built-in amorphous solar cells. The test solar power system has a generation output of 20-30 kW. Hybrid wind turbines are also used at the site to help generate power for use in the building. Other energy efficiency features include the use of LED and organic EL lighting, heat pumps, "ecotubes" under the floor of the building that reduce temperatures by around 3°C and transpiration cooling systems that spray a fine mist of collected rainwater on the roof. The ecotube system also allows sunlight into the building and the cooled floor also increases the chimney effect of the tubes, reducing the air-conditioning load by drawing in air. Exhibitions within the pavilion include a look at how technology is being used to create "zero-emission towns" in Japan.