Abstract
For the purpose of cooling high-temperature superconductor (HTS) devices, superconducting motors, SMES and fault current limiters, a large cooling capacity Stirling pulse tube cryocooler (SPTC) has been developed by Sumitomo Heavy Industries, Ltd. (SHI). The design concepts of the cryocooler are high efficiency, compact size, light weight and high reliability. According to the experiment results, with an in-line expander, a cooling capacity of 210 W at 77 K, and a minimum temperature of 37 K have been achieved. The compressor is operated at 49 Hz and the input power is approximately 3.8 kW when a heat load of 210 W is added to the cold-end. The compressor efficiency is approximately 74% and COP is approximately 0.055. However, a cryocooler with a COP of 0.1 is very important to realize the widespread use of HTS devices worldwide. In order to further improve the cooling efficiency, we study the energy flow and losses in the SPTC. The experiment results and the theoretical analysis are reported in this paper.
