Experimental Evaluation of a Single Stage Superfluid Stirling Refrigerator Using a Large Plastic Recuperator

Abstract

This paper describes the low and high temperature experimental performance of the second single stage superfluid Stirling refrigerator (SSR) to use a plastic recuperator. This SSR has a total internal volume of 96.6 cm3 and uses a Kapton recuperator which has 12.10 cm3 devoted to recuperative heat transfer. Operating from a high temperature of 1.0 K and with 1.5% and 3.0% 3He–4He mixtures, this SSR achieves a low temperature of 291 mK and delivers net cooling powers of 3705 μW at 750 mK, 977 μW at 500 mK, and 409 μW at 400 mK. Cooling power versus cold piston temperature for various frequencies of operation and for two piston stroke configurations are also provided. These results are non-dimensionalized and compared to the Schmidt model of a regenerative Stirling refrigerator and the adiabatic model of a recuperative Stirling refrigerator. The SSR was also operated from high temperatures between 1.0 K and 2.0 K. This SSR achieves low temperatures of 412 mK, 620 mK, 1.069 K, and 1.459 K operating from high temperatures of 1.2 K, 1.4 K, 1.6 K, and 1.8 K respectively. This high temperature performance is compared to the theoretical performance of the SSR using a phonon–roton gas model.