Researchers have discovered a remarkably simple method to significantly enhance the efficiency of cryogenic coolers, achieving near-absolute zero temperatures up to 3.5 times faster and using about 71% less energy than current technologies. This advancement holds immense potential for various applications that require extremely low temperatures.

Cryogenic cooling is essential for preserving biological materials such as tissues, eggs, sperm, and embryos. It enables the functioning of CAT scanners, CERN’s massive particle accelerators, and certain mag-lev systems. Moreover, it has numerous engineering applications, powers the James Webb Space Telescope’s deep-space observations, and could be crucial for future breakthroughs in fusion power and quantum computing.

At ultra-low temperatures, unique physical phenomena occur. Superconductivity allows electric currents to pass through materials without resistance, and superfluidity enables certain liquids like helium to flow without viscosity, defying normal rules by climbing over container sides. Approaching absolute zero, quantum phenomena slow down, enabling the creation of Bose-Einstein Condensates, where atoms clump together and behave as a single quantum entity.

However, reaching these temperatures has traditionally been expensive and time-consuming. For over 40 years, the Pulse Tube Refrigerator (PTR) has been the standard for achieving temperatures of 4 ºK (-452 ºF, -269 ºC), just four degrees above absolute zero. The PTR operates on a principle similar to a household refrigerator but uses helium gas to reach the lowest possible temperatures. While effective, this process can take several days and consume significant energy.

Ryan Snodgrass and his team at the National Institute of Standards and Technology (NIST) sought to enhance the PTR’s efficiency. They discovered that the PTR performs well near absolute zero but is inefficient at room temperature where cooling begins. The team found that at higher temperatures, the high-pressure helium gas was frequently diverted into a relief valve instead of contributing to cooling.

By reconfiguring the mechanical connections between the compressor and the refrigerator and adjusting the valves to start wide open and gradually close during the cooling process, the researchers achieved greater efficiency and faster cooling, all without wasting valuable helium.

The potential impact of this innovation is substantial. If the new refrigerator prototype were commercialized to replace existing equipment, it could save 27 million watts of power, $30 million in global electricity costs, and enough cooling water to fill 5,000 Olympic swimming pools annually. This breakthrough could dramatically alter the cost-benefit equation for various ultra-cold technologies, making them more accessible and sustainable.

By Impact Lab