Breakthrough cryocooler could transform HTS industry

Scientists at Industrial Research, together with leading US cryo-refrigeration company, CryoMech, have produced a breakthrough industrialised cryogenic refrigerator, or cryocooler, that is set to have a major impact on the high temperature superconductivity (HTS^[?]) industry.

While a standard refrigerator can remove heat from temperatures down to –20°C, a cryocooler removes heat from temperatures below –200°C, entering a strange realm where air becomes a liquid, and where physics predicts some weird and wonderful things.

One of those things is superconductivity, that is, electrical conduction without resistance. Until the late 1980s, superconductivity was restricted to a few materials around liquid helium (–269°C) temperatures, says Industrial Research cryogenics engineer, Alan Caughley.

Then came the discovery of high temperature superconductivity HTS , at the liquid nitrogen temperature of a mere –196°C. Whilst cryocoolers have been around for some  time, there is little that meets the needs of HTS, Alan Caughley says.

Alan Caughley and the HTS team have invented a patent-pending way of generating the pressure waves that drive a cryocooler. Their pressure wave generator is industrially robust, long lasting and will cost significantly less than the current technology available.

CryoMech is producing the cryogenically cold part of the new cooler, called the pulse tube cold head which is driven by the pressure wave generator. The new pressure wave generator has to produce enormous acoustic power to drive the pulse tube and that has provided many challenges during its three-year development, Alan Caughley says.

“We have had to produce 3.5KW of acoustic power. That’s a huge pressure wave, something like 210 decibels – the forces are enormous. I’d liken it to producing a medium-size rock concert inside a coffee cup. It’s quite a scary machine actually.”

IRL’s associate company, HTS-110^[?] Ltd, has been assigned an exclusive license to this IP to further develop and exploit the new technology.

Sohail Choudhry, CEO of HTS-110 Ltd, says the commercial prospects for New Zealand around the technology are excellent.

“Every HTS solution, globally, needs cryogenics. We have worked through the major issues and developed an industrial-level pressure wave generator that can be manufactured locally.

“We could soon be exporting a high-value, high-tech piece of machinery which has got to be good for New Zealand industry.”