Nikken Sekkei Ltd (Chiyoda-ku, Tokyo) announced March 2, 2020, that it has installed a compact woody "cool spot" using a solar power generation (PV) system and thinnings produced in Japan on a trial basis.
The cool spot, "Cool Tree Lite," was set up in "i-Garden Air," a redevelopment area of Iidabashi, Chiyoda-ku, Tokyo. The cool spot will be there until the end of September 2020. Its cooling unit is scheduled to start operation in or after May 2020.
Solar electricity will be used to power a mist generator, the cool bench using Peltier devices and other cooing devices. The cooing unit was developed jointly by Nikken Sekkei, Meiken Lamwood Corp (Maniwa City, Okayama Prefecture), Koei Co Ltd (Osaka City) and Murata Manufacturing Co Ltd.
In 2018, they developed "Cool Tree" with a hexagonal shape and a diameter of 7.7m and set it up at Kashiwanoha Smart City (Kashiwa City, Chiba Prefecture) and Nagoya Wild Flower Garden Blue Bonnet (Nagoya City).
The Cool Tree Lite installed this time is a new model that has a square roof measuring 4m on each side. It was developed as a compact model more suited for urban streets where the heat island phenomenon progresses.
In 2019, it was developed by using commercially-available Japanese cypress thinnings measuring 75 x 75mm and stacking cross laminated timbers (CLTs) having a thickness of 90mm for the foundation. Each component can be repeatedly assembled and disassembled by using bolts.
The Cool Tree Lite comes with JHS Co Ltd's solar panel (output: 650W) and Murata's storage battery (capacity: 2.3kWh). It is possible to reduce sensible temperature by about 5° with shade, mist generator and cool bench, according to Nikken Sekkei. Also, until the cooling unit begins operation, solar electricity can be used for lighting at night, charging smartphones, etc.