PERFORMANCE COMPARISON OF FREE-PISTON STIRLING CRYOCOOLERS WITH METALLIC AND NON-METALLIC PACKING IN WOUND REGENERATORS

In recent years, cryogenic technology has undergone continuous advancement. Compared with traditional multi-stage cascade vapor-compression cryocoolers, Stirling cryocoolers exhibit advantages such as compact structure, high reliability, and low environmental pollution, thus garnering significant attention from researchers. The regenerator, being the most costly component within Stirling cryocoolers, can see substantial production cost reductions through optimization of regenerator packing materials. Wound regenerators, owing to their compatibility with mechanical winding processes, eliminate material waste during fabrication. This approach significantly reduces both labor and material costs compared to stacked wire mesh regenerators, positioning wound configurations as a promising solution for cost-effective regenerator design. This study systematically investigates the internal losses, working characteristics, and refrigeration performance of a free-piston Stirling cryocooler prototype featuring wound regenerators. Experimental results demonstrate that at an operating temperature of 187 K, the Stirling cryocooler with non-metallic regenerator packing achieved a cooling capacity of 280 W, outperforming its metallic counterpart 180 W. Furthermore, the non-metallic variant exhibited a COP 0.2 higher than the metallic regenerator system, conclusively establishing the superior thermodynamic performance of non-metallic packing in wound regenerators.