According to Zeng Yan, chief architect of Institute of Solar Building Technology under CNECHS, the experimental house built in June is supported by three core techniques: insulation, energy collection and storage.

The 100 square-metre house has an embedded greenhouse that collects the sun's energy, which can be transferred to the surrounding bedrooms and living room by opening connecting windows and doors when the temperature drops in the evening.

"We fully respect the traditional style of architecture of Tibetans," Zeng said. For example, clay bricks were applied as the major construction material instead of concrete.

On top of this, Zeng and his team hoped to improve the layout of Tibetan housing by separating the people and livestock in order to prevent communicable diseases.

Yuzhen and her family are looking forward to the coming of winter, when the new housing will be put to the test.

A preliminary estimate by Zeng and his colleagues finds that the consumption of cattle dung could be potentially halved under the new model and the midnight temperature would be kept at ten degrees centigrade.

It will also be environmentally friendly.

"The emission of greenhouse gases will be substantially reduced, which is important to the protection of the fragile ecology of Mount Qomolangma," Zeng said.

"The design provides a good model for the vast western regions of China," said Xie Yuan, head of Department of Science and Technology of Qinghai Province. In late July, this type of experimental housing was also built around Qinghai Lake in Qinghai.

But this prototype may be unaffordable for many Tibetans, Xie said. The annual personal income in Yuzhen's village is less than 1,700 yuan, but the new house costs nearly 40,000 yuan.

"It will be financially difficult for us to construct this type of house by our own efforts, as we could only rely on our limited farmland to make ends meet," said Yuzhen.

In view of this, the local government is considering appropriating 15,000 to 20,000 yuan for each family to build the new house, said Yang Yan, a program manager from the program's sponsor.

In the initial stage, local Tibebans are encouraged to build houses with financial support from private enterprises like Dupont, said Yang.

Tibet is the richest province in China when it comes to solar energy. The yearly sunshine time surpasses 3,000 hours. There are several small-sized photovoltaic plants in operation, but they have not played a major role for the Tibetans yet because of high costs and maintenance.

The Tibetan pilot house has also led the way in the construction of solar-based houses in China.

In 2007, the Chinese Ministry of Science and Technology launched a project promoting the use of renewable energy into buildings. The target is to save energy equivalent to 220,000 tons of standard coal and 594,000 tons of carbon dioxide per year on new buildings covering 3.2 million square meters by 2012.

(Xinhua News Agency August 5, 2009)