by David-John Roth, subject matter expert in cryogenics, Cryoco LLC
Cryocoolers are making inroads into commercial applications and are getting closer to our everyday lives. It is well known in the cryogenics community that cryocoolers have been in increasing demand for wider applications. Traditionally, high end cryocoolers were developed for space-based applications such as flight hardware for unattended long life for surveillance and missile systems.
As new markets are identified and the competition between manufacturers increases, the cost for differing types of both small and large cryocooler units should go down. The availability and types of cryocoolers (Joule-Thompson versus Gifford McMahon) will each find a market niche application.
I teach cryogenic engineering to a broad audience of companies and government agencies every year and have noticed several trends. Atricure, a medical device company in Ohio, is using JT type technology to do ablative heart tissue surgery of mitigation of AFIB, while Johns Hopkins University and many medical companies continue to refine and develop reliable cryocoolers for reproductive refrigeration technology.
The LNG community is beginning to use cryocooler technology, developing large units that will use only natural gas raw feedstock for remote power as well as product liquefaction in one footprint. These new units will be called mini-plants. While not technically a cryocooler, the units make use of all of the components in larger compact engineered packages. These are innovative solutions made to fit a new market—the sole fleet owner or large farm that wishes to use LNG powered vehicles and machines. Presently, diesel fuel is just under $4 per gallon but natural gas liquefies to a cost of about $0.95 per gallon.
In the last two years there have been other emerging uses of cryocooler technology. The foremost, at present, is reliquefaction of helium. Several national labs and other large-scale users have begun programs to recycle helium within facilities by using helium liquefiers that include pulse tube technology and small scale in-situ mini-plants manufactured by companies such as Linde and Cryomech Inc., both CSA CSMs.
Another use that is coming closer to daily application is using coolers for breathing air apparatus. The density of liquid air is 600 times that of gaseous, and the liquid breathing units capacity far exceeds that of high pressure gaseous units. With NASA funding, BCS, a company in Florida, has been developing and manufacturing these liquid air breathing units for some time for fire fighter applications.
Space applications are also under test and we expect to be using these for life support in future space projects. The liquid air is produced using a Fabrum Solutions (CSA CSM) Pulse Tube cryocooler and the reservoir vessel is maintained by a Cryomech GM cryocooler. http://www.cryocourses.com ■