Design of Free Piston Stirling Refrigerator at Room Temperature

As a new type of refrigeration technology, free piston Stirling refrigerator shows the advantages of efficiency, reliability, compactness and environmental friendliness. To date, the free piston Stirling refrigerator at room temperature range has problems as low power utilization and large outlet acoustic work. As a result, the feedback acoustic work of the displacer and the refrigerator's size are both large, which brings difficulties to the technology promotion and real application. In this paper, the core of free piston Stirling refrigerator at room temperature is designed using SAGE software. By adopting the multi-stage refrigerator process, the acoustic work utilization of refrigerator is improved, and the influence of the displacer on the refrigeration performance is explored to find an effective method to reduce the diameter of the displacer. On the premise that the performance coefficient is taken as the optimization calculation objective with a limited displacer displacement, the minimum displacer diameter of three-stage free piston Stirling refrigerators with different core diameters is obtained. The calculation results show that the area of the displacer of the three-stage free piston Stirling refrigerator can be reduced to 49% of that of the single-stage refrigerator when the total core equivalent area is similar. That is, the multi-stage refrigerator effectively reduces the size of the displacer and promotes the application of the free piston Stirling refrigerator at room temperature. © 2021, Science Press. All right reserved.