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"

Related:

Scientists develop first-of-its-kind cooling technology — and it could be vital for a futuristic fuel source
https://www.thecooldown.com/green-tech/hydrogen-liquefaction-netherlands-scientists

World’s First 500MW Hydrogen-Cooled Generator
https://www.energy-reporters.com/environment/china-just-fired-up-the-future-as-worlds-first-500mw-hydrogen-cooled-generator-sparks-global-race-and-us-backlash-over-clean-energy-dominance/#google_vignette