Test of a 15-20 K Stirling/pulse Tube Hybrid Refrigerator for Space Applications

The two stages gas-coupled Stirling/pulse tube refrigerator (SPR), whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles, is a promising spaceborne refrigerator. The SPR has many advantages because of the unique configuration combining each feature of the Stirling and pulse tube refrigerators, such as compact structure, high reliability, and outstanding performance. A SPR-20 has been designed and manufactured. When all of the regenerators are filled with stainless-steel mesh, the SPR-20 can obtain 2.6 W at 70 K plus 0.1 W at 20 K with 160 W total input power. While the second stage regenerator is mixed filled with magnetic material and stainless-steel mesh, the cooling capacity of the SPR-20 can be improved to 2.5 W@70 K plus 0.45 W@20 K with 200 W electric input power plus 17 W displacer input electrical power. Meanwhile, the SPR can obtain 0.32 W at 15 K plus 0.65 W at 65 K with 250 W compressor input power plus 20 W displacer input electrical power. The performance of the developed Stirling/pulse tube hybrid refrigerator (SPR-20) has a relative advantage among 20 K high-frequency refrigerators.