Energy / Climate Change

November 17, 2009


District Heating and Cooling for 'Tokyo Sky Tree' Area to Include Japan's First Application of Geothermal Energy

Keywords: Climate Change Non-manufacturing industry Renewable Energy 


Tobu Railway Co., a major private railway operator in Tokyo and surrounding prefectures, obtained a business license on February 17, 2009, to supply heating to the "Tokyo Sky Tree District" -- a 10.2-hectare area in the Narihirabashi/Oshiage area and the surroundings of Sumida Ward in Tokyo -- based on the Heat Supply Business Act. The company expects to complete the district development project centered on the 634-meter "Tokyo Sky Tree" tower by spring 2012. The project will introduce Japan's first district heating and cooling (DHC) system that utilizes geothermal energy.

DHC is a system where one or several plants generate chilled/hot water in order to provide heating, cooling, and hot water through pipes to buildings within the district. It has several advantages over the conventional distributed heating and cooling systems: energy efficiency, carbon dioxide (CO2) emissions reductions, heat island effect mitigation, secondary disaster prevention, and cost efficiency. The project is expected to achieve an overall annual energy efficiency rate (coefficient of performance, or COP) of more than 1.3 - the best in Japan - and reduce annual primary energy consumptions and CO2 emissions by 43 percent and 48 percent (2,271 tons), respectively, compared to the distributed systems.

Taking advantage of the fact that temperatures in the ground remain at about 15 to 17 degrees Celsius throughout the year, the geothermal energy system utilizes the earth as a heat source in the winter and heat sink for cooling in the summer. The geothermal heat pump transfers the heat to or from the ground, by circulating fluids through two sets of water pipes buried at 32 meters and 120 meters below ground, to boost efficiency of heating and cooling.

A Key to Urban Comfort and Efficiency
Japan's District Heating and Cooling Systems No.82 (June 2009)

Posted: 2009/11/17 06:00:15 AM