Thermoacoustic Cryocooler with Multi-cold Fingers for High Temperature Superconductor

Abstract The commercialization of high temperature superconductors (HTS) in the near future becomes the focal topic nowadays. Consequently, larger cooling capacity cryocoolers are in urgent need to support such technology. Considering the inhomogeneous gas flow and temperature distribution in regenerator caused by the enlargement in diameters, the pulse tube cryocooler (PTC), although providing high reliability and high efficiency, has encountered a bottleneck to further increase its cooling capacity. This paper designs a new system composed of three parallel identical cold fingers driven by an opposed linear compressor. Experimental results have shown that each of the three PTCs has good consistency, performing as well as the situation when working separately. With charge pressure of 2.5 MPa and working frequency of 54 Hz, the three cold fingers reached the minimum temperature of 36.5 K, 37.3 K and 36.3 K respectively, and obtained total cooling capacity of 230 W at liquid nitrogen temperature with the system overall relative Carnot efficiency reaching 13.2%. It successfully avoided the problems coming out in the traditional large capacity PTCs and will have hopeful prospects when applied to the occasion of large cooling capacity.