Japanese general contractor Shimizu Corporation says its new headquarters, which opened Wednesday, is the world’s least carbon dioxide-emitting building. The Shimizu headquarters, located in Tokyo, emits 38 kilograms per square meters of CO2 per year, 62 percent less on average than conventional buildings in the city, the company said in a statement.
The Shimizu statement says the company developed and adopted a variety of technologies in the building in an effort to improve efficiency, cut gas and oil use, and reduce CO2 emissions. For example, the company uses an air conditioning system that makes use of radiant heat. Water hoses are installed under ceiling boards, helping to control the temperature of the water circulating in the hoses and, in turn, the ceiling board surface. The surface absorbs the heat of people working in the office, and the system can reduce CO2 emissions by 30 percent compared with conventional air conditioning systems, according to the company.
The building is equipped with motion sensing LED lighting. Energy used for lighting is generated by photo voltaic (PV) panels installed on the outer walls. The area of PV panels is about 2,000 square meters and is expected to generate 84,000 kilowatt hours of power annually.
Shimizu also installed window shades, which angle automatically to follow the sun and optimize natural light.
Shimizu says that by 2015 it will further reduce CO2 emissions to 70 percent less than conventional buildings, by fine tuning equipment and adopting additional energy saving systems.
"There isn’t a clear certification standard for zero-energy buildings, which makes it difficult to verify this building’s claims," Eric Bloom, a senior research analyst at Pike Research, told local media. "However, the building definitely uses a number of highly energy efficient and CO2-reducing features that aren’t commonly seen in large buildings, such as the radiant heating and even the solar installations."