Under support of NEDO, Nihon University’s College of Engineering and Nissho Techno Co. have found a new construction method digging into depth of less than 20 m. The two features of this procedure are a rotary burial construction method, where steel pipes used as underground heat exchanger penetrate the underground while rotating; unlike in ordinary excavation methods, this method features quietness and no waste soil. The second innovation is a double pipe type heat exchanger: the heat exchanger is composed of an inner and an outer pipe, and a fluid flowing between the outer and the inner pipe wall exchanges heat with the soil through the outer pipe wall. In a test field at Nihon University, significant cost saving was achieved, reducing the installation cost by 40% and operating cost by 10%.

NEDO news release, June 25, 2018