First of all, a dual mixed-gases Joule–Thomson refrigeration system was designed, constructed and tested in this work. A minimum no-load temperature of −197.7 °C (about 75.5 K) was reached and about 110 W cooling capacities at −174 °C (about 99 K) was obtained with the mixed-gases refrigeration prototype. Secondly, a cryogenic chamber for biomaterials preservation was built and tested with the similar cycle configuration, which h...