National Stadium (2009 World Game Main Stadium)
|Case name||2009 World Game Main Stadium|
|Case location||Zuoying, Kaohsiung|
|Erection style||Green Architecture|
|System type||Building Integrated PV|
|System power output||1 MWp|
|Energy company||Delta Electronics|
Chinese people are known to be descendants of the Dragon, which is why the dragon image exists on much of our architecture, not only on traditional structures, but also on our modern Kaohsiung Stadium. The city of Kaohsiung enjoys 2,212 hours of sunlight per year, therefore it is ideal to promote solar power generation with modern construction. One of the leading solar projects in Kaohsiung City is the National Stadium. National Stadium, also known as the 2009 World Game Main Stadium, not only differs from classic stadiums in design and construction, but also in power consumption. The stadium roof consists of 8844 solar panels and self-supports 80% of all electricity consumed by the stadium.
(1) The Technological and Architectural Design of the National Stadium
Designed by Japanese architect Toyo Ito, the National Stadium opened in July 2009 for the 2009 World Games held in the R.O.C. The stadium is designed with an open circle with roof top solar panels that resembles a scaly dragon wagging his tail. Such a design is not only for aesthetic or auspicious reasons, but also due to local weather conditions. From the analysis of the Central Weather Bureau, it was understood that a semi-open stadium could create a passage through which summer wind may pass, refreshing the audience during Kaohsiung’s humid summers. It is due to this cooling design that air-conditioning is not needed even in summer.
(a) National Stadium
Source: IEK, Industrial Technology Research Institute
The surrounding environment of the stadium is landscaped with palm trees and plants imitating a tropic forest. Its open design and wind-sun-conforming orientation provide a welcoming and comfortable sports ambience. The solar panels allow 30% of total sunlight to shine into the stadium, so the audience may enjoy natural outdoor sunlight. Spectators can observe the spiral steel bracings of the roof through the transparent glass roof, thanks to the BIPV technology implemented here.
The stadium was commissioned by the Kaohsiung City Government with the assistance of Dow Chemicals and Fu Tsu Construction. The solar power system was integrated and constructed by Delta Electronics Group, including the design and manufacture of the cells and modules. Delta Group is a leading corporation in power and thermal management solutions. Many significant achievements led Delta to receive many awards for innovation and design worldwide. The transparent solar panels were all designed and manufactured in-house. The panels cover a surface area of 14,155 square meters integrated into the roof construction. The stadium’s solar energy system also uses Delta’s energy inverters to convert DC to AC power and to feed electricity into the grid with inverting efficiency of 98%. The stadium is certified by the International Association of Athletics Federations as a first-class sports arena and is the largest solar powered sports stadium in the world. The building was constructed with spiral steel girders that support a saddle-shaped solar cell roof which occupies 19-hectares. It consists of three floors above ground and two basement levels with housing capacity for 55,000 spectators. A reinforced concrete base is used to hold a complex structural framework of pipes and steel beams that supports the 8844 BIPV panels mounted as the roof. In addition to the solar power roof, all construction materials used are 100% recyclable and manufactured in the R.O.C.
(b) National Stadium Rooftop BIPV Panels
Source: National Stadium Headquarters, Sports Affairs Council, Executive Yuan
(2) Green Energy Output
The stadium’s 8844 panels generate an average of 3000 kWh per day and supply up to 1.14 gigawatt hours of electricity annually. With the installation of 279 units of 3.6kW solar inverters, the PV roof could support the 3,300 lux of illumination within the stadium. As exhibited in the photos, the solar panels covering the vast external face of the stadium are able to generate most of the power required for its operation. The power generated from the panels allows the stadium to support 80% of its own electricity consumption and sell excess power to Taiwan Power Company, saving a large percentage of its electricity bill and reducing 660 tons of carbon dioxide emission. During the non-games period, the surplus energy can be saved and sold. Its solar energy system meets 1 MWp (megawatt peak) capacity and can generate 1.1 M kwh of electricity annually. Moreover, the stadium roof also collects rainwater for use inside the stadium. A system of pipes carries rainwater to underground storage facilities where it is sterilized and reused.
Design, construction and material use were all new challenges for all parties involved in the National Stadium project. The stadium was to conform to international sports standards while at the same time demonstrate its qualities as an innovative green building. Some of the barriers needed to overcome were optimal energy transfer rate from the PV panels, weather tight performance, and thermal and acoustic designs. With the assistance of construction geniuses from Japan, US and R.O.C., National Stadium has become a proud milestone in green architecture application.