Speaker
Description
To improve the efficiency of a cryocooler, an effective way is to improve the efficiency of the regenerator. In general, the heat capacity of materials decreases as temperature decreases. Thus, when temperature is below 40 K, lead or bismuth spheres are often used as a regenerator material. However, the pressure drop in a sphere regenerator is much larger than that in a screen regenerator. To overcome this dilemma, Xu, et al reported a tin-plated screen in ICEC-ICMC 2016. However, the reliability of tin at low temperature is still not fully verified since there is a phase transition from α to β, which may result in a reduction of mechanical strength. In this paper, another candidate, zinc-plated screen, is proposed. A comparison test was performed with a two-stage GM cryocooler by replacing part of the first stage regenerator material, phosphorus bronze screens with zinc-plated screens. Compared to a regenerator filled with bronze screens, the cooling capacity of the first stage increased by about 11% at 40 K and 60% at 30 K with such zinc-plated screens. The detailed experimental results will be reported in this paper.