Shimizu Corp, the largest contractor in Japan, has opened a building that emits the world's least amount of CO2. The building is the new Shimizu headquarters located in Kyobashi, Tokyo.
The state-of-the-art building emits only 38 kg/sq meter of CO2 per year, 62% less on average than ordinary buildings in Tokyo. Since Japan has few natural resources such as oil or gas and has faced energy crises twice before, buildings there are designed to conserve energy.
Shimizu has developed and adopted various technologies to reduce CO2 emissions. One representative technology is an air conditioning system that makes use of radiant heat. Water hoses run under ceiling boards like capillary vessels. By controlling the temperature of the water circulating in the hoses, the temperature of the ceiling board surface is controlled. As a result, a surface temperature of about 20 degrees absorbs the heat of people working in the office through a radiant effect. This system can reduce CO2 emissions by 30% compared with conventional air conditioning systems.
The lighting system also makes use of energy-efficient technology. Light-emitting diode (LED) lighting is fully adopted and controlled by motion sensors. Energy used for lighting in the daytime is generated by photovoltaic (PV) panels placed in the outer walls. The area of the PV panels is about 2,000 sq meters and generates 84,000 kwh of power per year.
Furthermore, Shimizu has installed window shades that allow sunlight into the offices. The shade angle automatically changes to follow the sun. These efforts make it possible to reduce CO2 emissions by 90% compared with a standard lighting system.
By the end of the year 2015, Shimizu said it will reduce CO2 emissions down to 70% through fine tuning air conditioning and lighting facilities as well as adopting further energy saving systems. The company will offset the remaining emissions by creating emission rights to realize Zero Emission Building (ZEB).© Business Wire
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Admirable effort. But 84,000 kWh per year amounts to only 9.6 kW (84000/24/365) on average which hardly seems worth it. 2000 square meters of panel just to boil 3 kettles? Um... have I got it wrong?
This is good. Now, if they could also learn how to insulate buildings...
So how are they going to pay for light pollution related illness? CCFL are bad enough for you, limited spectrum LED is basically asking for headaches, fatigue, and perhaps more serious conditions in a small portion of their workers.
JonathanJoAug. 03, 2012 - 07:05AM JST
2k m^2 should be producing around 100-150W/m^2, for 200-300kW. At 12% duty that is normally assumed, you would expect more than 200000kWh/yr. At that rate, they are putting off far more CO2 making the panels than they will offset in twenty years. Not to mention spending more than 90 million yen on it.