A Wooden Zero-Energy Cool Spot
— Test Run Launch of COOL TREE LITE —

 On June 2, Nikken Sekkei Co., Ltd. (Headquarters: Chiyoda Ward, Tokyo / President & CEO: Tadao Kamei) launched a test run of COOL TREE LITE, an eco-friendly cool spot installation, at i-Garden Air in Iidabashi, Chiyoda-ku, Tokyo just before the summer temperatures are set to soar.
 COOL TREE LITE is the second installation in the COOL TREE series, a zero-energy cool spot assembled with thinned timber sourced from Japan and solely operated with photovoltaic power. The first COOL TREE was developed in 2018 by four companies—Nikken Sekkei Ltd., MEIKEN LAMWOOD CORPORATION, Ltd. (Headquarters: Maniwa City, Okayama Prefecture / President & CEO: Koichiro Nakashima), Koei Co., Ltd. (Headquarters: Osaka City, Osaka Prefecture / President & CEO: Joichi Sakagami), and Murata Manufacturing Co., Ltd. (Headquarters: Nagaokakyo City, Kyoto Prefecture / Chair of the Board & President: Tsuneo Murata)—to contribute to the development of an urban area that offers a comfortable outdoor living environment in midsummer. COOL TREE LITE is a compact, 4m x 4m square-shaped version of COOL TREE developed in 2019 in a size and shape that is a better fit for a cityscape.

 In cities that have experienced the spread of the novel coronavirus (COVID-19), the ability to spend time in comfortable, well-ventilated outdoor spaces is more important than ever. We believe that an open-structure installation like COOL TREE LITE will likely be in high demand as a place where people outdoors can sit and pause, each in her or his own distinct way.
 COOL TREE LITE will contribute to the creation of a more livable city with the use of eco-friendly, zero-energy technology.
  •  COOL TREE LITE Photo taken on June 2 ©Nikken Sekkei



Height: Approx. 2.9 m, Size: (Roof) 4.0m x 4.0m (Base) 4.8m x 4.8m, Total weight: Approx. 3,500kg

①Cool sensation from mist, sunshade and cool contact

・Mist cools the air through the heat of vaporization and creates a visually cooling sensation.

・The lattice hinoki cypress sunshade provides an open feel and blocks direct sunlight like a canopy of trees.

・Sitting on a “cool bench” that uses the Peltier effect cools people’s bodies down.

*1 Peltier effect: Effect of absorbing and releasing heat at a junction where different metals are joined, voltage is applied and a current flows.

②Self-sufficient zero-urban energy system using solar power and IoT control

Solar panels are installed above the latticed sunshade, so the power driving cooling devices, such as the cool bench and mist, is all derived from solar energy. Power generated from the solar panels is temporarily stored in a storage battery, which is then used to operate the devices.
With this energy-efficient ingenuity, a zero-energy system has been developed that is completely independent from urban energy infrastructure.

③Ecological system using the 3Rs (reduce, reuse, recycle)

COOL TREE LITE uses 75-mm2 thinned hinoki cypress wood that is generally available with 90-mm thick CLT (Cross Laminated Timber) panels layered and joined together to form the foundation.
The use of thinned wood can reduce the energy needed to produce building materials.

COOL TREE LITE can be repeatedly assembled and dissassembled by joining together each of the parts with bolts only.

Wood can be recycled as materials for biomass power generation, and iron can be recycled and reused as scrap for electric furnace materials.

Test run at i-Garden Air

・Installation period: March 2 to September 2020 (planned)

・Operational period for cooling devices (mist and cool bench): June 2 to September 2020 (planned)

・Timers have been set for cooling devices and the test run will start with standard hours from 10:00 to 16:00.

・COOL TREE LITE will be lit up until 23:00 at night.

・Outlets have been installed in two places that can be used to charge smartphones.

* The test run is subject to change depending on weather and operating conditions.
* If the storage battery charge is running low due to weather conditions or for other reasons, operations will be suspended temporarily.

・Location: i-Garden Air Central Plaza, “Front Forum”
3-10 Iidabashi, Chiyoda-ku, Tokyo
About a 10-minute walk from the nearest stations (Iidabashi Stn., Suidobashi Stn., Kudanshita Stn.)

Original COOL TREE installations

・The original COOL TREE with a diameter of 7.7 meters was installed at Kashiwa-no-ha Smart City (Chiba Prefecture, July 2018 to September 2019) and Nagoya Port Wildflower Garden Blue Bonnet (Nagoya City, July 2019 to present).


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