A rainwater collector is installed in the courtyard. Photo: Xu Tianran

By Xu Tianran

The first "green lifestyle" siheyuan courtyard complex in the capital city was announced to the public Tuesday after Daxing Community Residents Committee in Chaoyang district completed its extensive low-carbon reconstruction.

Sino-Ocean Land Holdings real estate company had sponsored and designed the reconstruction to promote its "old green community" and "zero event" campaign, said Li Deqing, community chief of Daxing Lu.

Reconstruction that started July 13 adopted low-carbon technologies including:

â–ºrain and melted snow water is stored by an underground collection system and used to water plants;

â–ºdouble-glazing to replace traditional windows and slash heat penetration from both inside and outside;

â–ºan adjustable outer bamboo blind to shield windows from the heat of the sun;

â–ºventilation outlets high above the wall and ceiling grilles to generate a convective air current that dissipates the heat;

â–ºwalls coated with a low heat-conducting paint; and,

â–ºenergy-efficient lights that save up to 90 percent of energy compared to traditional filament lamps.

Two four-square-meter solar panels power all the courtyard's electronic equipment except the air conditioner, Li said. The air conditioner shouldn't need to be used for more than 20 days a summer, she believed.

"There's also a stationary bike in the yard that will charge up the battery when people ride it," she said.

The project had obviously employed single-crystal panels, said Zhang He, a researcher for Global Village Beijing, a non-profit organization dedicated to environment protection.

These were the most effective solar panels on the civilian market with a light-power conversion efficiency of 16 to 19 percent, he said.

"Theoretically, their claim of powering all the equipment without alternating current power from outside is very feasible," he said.

"The engineering methods taken to reduce or maintain the temperature in the room have also been proven effective as well."