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A prototype Peltier refrigerator junction for operation at around liquid nitrogen temperatures has been built consisting of a thermoelectrically active bismuth-antimonide alloy leg and a thermoelectrically passive superconducting YBa2Cu3O7−δ leg. The junction has shown a maximum cooling of 5.35 K below a heat sink held at 79 K. Improvements in materials and design and operation in a magnetic field could result in cooling of up to 16 K.

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A vital requirement for commercial application of Bi-2223 tapes is that the high critical current densities currently obtainable in short or intermediate lengths can be maintained when piece-lengths are scaled up by more than an order of magnitude. In this paper the effects of statistical variations in local I-V characteristics on the critical current of long superconducting tapes are investigated computationally. The local I-V characteristic is parameterized by the standard power law parameters I, and index n. Analytic solutions and simulated data are presented for a number of statistical distributions in local I-V parameters, including Gaussian, Weibull and polynomial distributions. The study concludes that for typical parameters, given local statistical variations in I,, there should be no significant loss in performance as tape lengths are scaled up by factors of 10 to 100.