An efficient high cooling-capacity 40 K pulse tube refrigerator using an active dual-piston as phase shifter

Superconducting systems can reduce the generation of Joule heat and improve energy utilization efficiency, which has a broad application prospect. Improving the energy conversion efficiency of the refrigerator in superconducting systems is crucial, which can further improve the energy utilization efficiency of superconducting systems and promote the large-scale application of superconducting systems. In this paper, an electrical analogy model is developed to calculate the energy conversion efficiency of the pulse tube refrigerator with active dual-piston. And a 40 K pulse tube refrigerator with a high cooling capacity using active dual-piston is designed and fabricated, the accuracy of the model is verified by comparisons of cooling capacity, compressor efficiency, and power of active dual-piston at 300W input electrical power of the compressor. A cooling capacity of 7.17 W can be obtained at 40 K with an electrical power of 506 W. The active dual-piston electrical power reduces from 20 W to 0 W as the diameter of active dual-piston decrease from 24 mm to 18 mm. This study contributes to designing and optimizing a high-energy conversion pulse tube refrigerator with an active dualpiston.