Peltier cooling of superconducting current leads

• Published in: Cryogenics (Guildford) Vol. 41; no. 7; pp. 521 - 528
• Main Authors: Gehring, F.K., Hüttner, M.E., Huebener, R.P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2001; Elsevier
• Subjects: Applied sciences; Bridge circuits; Cryogenics; Doping (additives); Electric contacts; Electric currents; Electric rectifiers; Electric resistance; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat losses; Low temperature effects; Peltier effect; Refrigerating engineering. Cryogenics. Food conservation; Temperature; Cooling; Cryogenics; Power losses; Superconductor device; Experimental study; Peltier effect
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/S0011-2275(01)00124-2

An interesting application of Peltier cooling based on the Peltier materials presently available arises for the cooling of current leads connected to superconducting power electronics. By inserting n-doped and p-doped Peltier tablets at the warm end into the circuit, at their warm side the remaining current leads can be Peltier cooled about 50–60 K below room temperature. We have developed an experimental test apparatus for dc operation up to a current of 200 A. Our experiments, performed with Peltier tablets fabricated from n-doped and p-doped Bi 2Te 3, well confirmed the expected Peltier cooling. From our results we estimate the reduction of the thermal losses (by typically 13%) and of the electric power losses (by typically 10%) due to the insertion of the Peltier tablets. In addition to the dc experiments, we have also carried out similar experiments using 50 Hz ac and a bridge circuit yielding a rectified output current. Minimization of the electric contact resistance generated at the surfaces of the Peltier tablets (and of the rectifying diodes required for ac operation) represents an important issue.