Commercial Induction Heaters With High-Temperature Superconductor Coils

The induction heater for aluminum, copper and brass extrusion billets is an application where high-temperature superconductors (HTSs) provide clear benefits compared to conventional technology. With an energy efficiency of just some 50% for conventional technology and limitations in processing speed, the potential for improvements is evident. A novel heater design based on superconductors, and a fast product development have led to an industrial breakthrough. With one unit in operation since August 2008 and four more sold, the superconducting induction heater has become the first true commercial HTS product. Radical efficiency increases, improvements in process speed, quality and cost have been demonstrated in a rough industrial environment. In this paper we explain how to fully utilize the superconductor in this application by altering the established concepts of induction heating. The electromagnetic realization as well as cryogenic integration based on off-the-shelf cryo-coolers are described. Furthermore, operational experience from heating up 10,000 tons of aluminum (350,000 billets) in the first commercial installation is presented.