Cooling of the 200 m superconducting DC power transmission system at Chubu University

The fourth cooling test of the superconducting DC power transmission system of Chubu University was conducted in August of 2011. The heat leak from the cryogenic pipe and the eect of reducing the outer pipe temperature were tested. The heat leak from the cryogenic pipe was improved relative to that recorded during the second cooling test performedintheprevious summer,a season similartothatin whichthe fourth cooling testwas conducted.Asignificant reduction of the outer pipe temperature was achieved by an infrared reflective coating, and a reduction of the heat leak was observed.