by Xinhua writer Quan Xiaoshu

BEIJING, July 15 (Xinhua) -- Committed to a "green" Olympics, Beijing has built its key Game's venues into not only showpieces among the most imaginative and impressive architectural feats in the world, but also energy-saving role models.

The National Stadium, known as the "Bird's Nest" for its unique latticework of interwoven steel, is considered a template for water conservation, with 70 percent of its supply coming from recycled water.

"The recycled water will be used to wash the racetrack and water the plants around the venue," said Li Jiulin, chief engineer of the stadium construction.

Li noted that 23 percent of the recycled water would be collected from rainfall, and the rest recycled from industrial waste-water and urban sewage.

In talking about the sophisticated rainwater re-use system fanning from the Bird's Nest, Li became excited when describing its intricate details.

"Through the system, rainwater that falls on the stadium's roof,playing field and its more than 20,000 square meters of surrounding area will be collected and channeled to a 12,000-cubic-meter pond.

"The water will then go through three screens of filtration -- quartz sand filtration, micro filtration and ultra filtration, to clear harmful elements."

Beside the Bird's Nest, the National Aquatics Center, or the "Water Cube," has also been designed into a comprehensive energy-saving building.

"Special measures have been imposed to reduce water consumptionand sewage discharge," said Sun Hongzhuang, project manager with the China Construction First Division Group Construction and Development Co., Ltd, builder of the structure.

It is able to collect 10 million liters of rainwater, 70 million liters of bath water and 60 million liters of swimming-pool waste-water annually to wash the ground, flush toilets, supplement the water supply for the cooling tower and water the plants around the venue, Sun said.

Its blue bubbling translucent exterior, also a part of the Water Cube's environmental design, is said to allow the sunlight to be harnessed to heat the swimming pool and save thermal loss.

NEW ENERGY MODELS

Apart from cutting energy consumption, some Games' venues are also trying new energy supply systems, which environmentalists hope is not just a practice of a green Olympics, but also a model for the entire country now searching for a road of sustainable development.

A set of solar power generators with a capacity of 100 kw has been installed in the National Stadium's roof and south glass wall to supply power for its underground parking lot, Li said.

After the Olympics, the solar power produced by the stadium will be merged into the city's power grid and provided to local families if there are no sport events there.

The solar power generators installed around the Chaoyang Park Beach Volleyball Ground are more delicate, as their solar plates adjust to the angle of the sun's movement for a maximum absorptionof sunlight.

In the Beijing Science and Technology University Gymnasium, which will host the judo and taekwondo matches, 148 light conductors, each eight meters long, help transmit 80 percent of the sunlight into the gym, enough for the athletes' training or physical education classes.

"There's hardly any necessity to turn on lights inside the gym in the daytime, and the conductors can also pass the indoor light out at night, making the gym a good night view," said an official in charge of the building's reconstruction work.

NATURAL VENTILATION

With scorching sunshine and no air conditioning, it can be somewhat torturous to watch an open air tennis match.

But the flower-shaped Olympic Green Tennis Center, with a seating capacity of 17,400, can assure a more comfortable environment.

The center's three main courts, all dodecagonal with each of the 12 sides as a stands, are said to be five degrees Celsius cooler than the temperature outside.

The air is allowed to flow in the courts through the gaps between the stands, which are spread out like 12 petals of a lotus flower. The set-up forms air circulation inside the court with a wind speed of up to two meters per second, an official in charge of the center explained.

"The Olympic venues will leave us a great treasure, a paragon for energy saving and environmental sustainability," he said.

(Xinhua reporter Sun Xiaosheng contributed to this story)