A Method to Buffer AC Losses in a Forced Flow Superconducting Magnet
A SMES device is proposed for an application requiring repeated charging and discharging over a short period of time, followed by a long period of relatively low usage (standby). The magnet consists of a toroid wound with a cable-in-conduit conductor (CICC) cooled by forced flow supercritical helium, each coil module containing a limited helium inventory. The hypothetical operating scenario results in high energy deposition due to AC losses into the SMES magnet over the short (less than one hour) operating period on an approximately daily cycle. Removing this energy deposition in real time would require a refrigeration system of extraordinary size. To reduce the size of the necessary cooling system, while maintaining operability in the postulated scenario, the supercritical circuit includes a large separate helium inventory to buffer the AC loss energy deposited during the discharge cycle. A methodology is described to establish the required supercritical inventory for magnet pulsed operation, and to compare the present approach with steady-state removal of AC loss loads.
KeywordsHeat Load Storage Volume Refrigeration System Operating Scenario Pulse Operation
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