The Korea Institute of Energy Research (KIER) has developed a groundbreaking refrigeration and freezing technology that uses air as a refrigerant, offering an eco-friendly solution to replace high-GWP refrigerants like Freon gas and hydrofluorocarbons (HFCs). This innovation addresses the European Union's revised regulation on fluorinated greenhouse gases (F-gases), slated to phase out products containing F-gases starting in 2025.
In response to the urgent need for alternative technologies impacting key Korean export products such as air conditioners, automobiles, and semiconductor processes, KIER's researchers have successfully developed an integrated ultra-high-speed compander system. This advanced system combines a compressor and an expander, utilizing cutting-edge design technology to achieve temperatures as low as -100 degrees Celsius.
This technology marks the first instance in Korea of an air cooling system that forgoes traditional refrigerants in favor of air. Traditional refrigeration methods rely on liquid refrigerants that evaporate to absorb heat, contributing significantly to global warming. In contrast, KIER's system employs the reverse-Brayton cycle, which compresses gas, then uses heat exchange and expansion to produce low-temperature gas without liquid refrigerants.
"The development of this system is a direct response to environmental regulations, driving the transition to eco-friendly refrigerants," stated Dr. Beom Joon Lee, the lead researcher. "We are currently enhancing the system's performance to achieve temperatures below -100 degrees Celsius. This technology will find applications in fields requiring ultra-low temperatures, such as semiconductor processes, pharmaceuticals, and biotechnology."
Dr. Beom Joon Lee added that the precision engineering required for the compander system involves tolerances within 0.1 millimeters for component gaps and shaft displacement. Integrating the compressor, expander, and motor on a single shaft, the system ensures each component operates efficiently while maintaining stability at ultra-high rotational speeds.
The air cooling system using this compander has successfully cooled air to below -60 degrees Celsius within an hour and demonstrated superior efficiency at temperatures below -50 degrees Celsius compared to traditional systems. Theoretically capable of reaching -100 degrees Celsius, it is expected to improve refrigeration efficiency by more than 50% over vapor compression systems.
This research was conducted with support from the "Climate Change Response Technology Development Project" by the Ministry of Science and ICT, led by Dr. Beom Joon Lee, and the basic research program of the Korea Institute of Energy Research, led by Dr. Hyung-ki Shin.
KIER's innovative air-based refrigeration technology is set to revolutionize sectors requiring ultra-low temperatures, providing a sustainable and reliable solution for the future.
