Computational analysis of Peltier current leads

Abstract

Many superconducting magnets require current leads to carry hundreds or thousands of amperes. Unfortunately, these current leads are the largest source of heat leakage to the liquid helium system and a large energy expense. One proposal to improve this involves the use of a segmented current lead, composed of high-temperature superconducting material (HTSC) below 77 K, copper between 77 K and 200 K, and n- or p-type thermoelectric (TE) materials between 200 K and 273 K. By limiting heat leakage to a liquid nitrogen (LN) bath, large energy savings are predicted. We present calculated solutions to the TE heat flow equations between 77 and 273 K for various hybrid Peltier current leads. We find that, the total heat leakage into the liquid nitrogen bath can be minimized to 21 W/kA maximum current. In economic terms, this represents a modest improvement over more standard LN-techniques.