Refrigeration system developed to replace harmful refrigerants with air

https://techxplore.com/news/2024-08-air-based-refrigeration-refrigerants.html

"ultra-high-speed compander used in air refrigeration, instead of vapor compression cycle... -60°C in 1 hour (-100 coolest)... reverse-Brayton cycle compresses air, then goes through heat exchange/ expansion cooling air... gaps between components and shaft displacement require tolerance within 0.1 mm... connects compressor, expander, motor on single shaft, ensuring stable operation even at ultra-high rotational speeds... higher refrigeration efficiency below -50°C... semiconductor processes, pharmaceuticals, biotechnology"