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Product Spotlight: Cryomech AL630 Cryocooler


Peter DeCew
Business Analyst

The Cryomech AL630 serves as the largest Gifford-McMahon (GM) cryocooler in the Cryomech product line. It pushes out an astounding 100 W of cooling capacity at 20 K. It is easy to maintain and has superior reliability, and has proven very popular in several emerging applications, such as fusion research and hydrogen liquefaction.

What is a Gifford-McMahon Cryocooler?

Cryomech is the “Gifford” in Gifford-McMahon. Cryomech’s founder William Gifford developed the GM cycle over 60 years ago in the late 1950s. GM cryocoolers are designed around a displacer in the refrigeration cycle that is either mechanically or pneumatically driven.

The pneumatic GM refrigeration cycle that Cryomech uses starts with the rotation of a valve that opens a high-pressure path. This allows the high-pressure helium to pass through the regenerating material and into the expansion space. The difference in pressure drives the displacer up, allowing the gas at the bottom to expand and cool. The next valve rotation then opens the low-pressure path, allowing the cold gas to flow through the regenerating material which removes heat from the system. Finally, the pressure differential returns the displacer to its original position to complete the cycle.

The GM refrigeration cycle is very reliable and efficient; GMs operate at slower speeds compared to other types of cryocoolers, increasing the longevity of the wear components, and delivering superb reliability.

Since William Gifford developed the first commercial Gifford-McMahon Cryocooler in 1963, over 20 different baseline Cryomech models have been introduced. Whether you need 10 watts or 600 watts of cooling power, we guarantee there is a product that’s perfect for every application.

Interior of the JET tokamak in Culham, UK.
Interior of the JET tokamak in Culham, UK; credit: UKAEA, courtesy of EUROfusion.

AL630 Applications: Fusion Reactors

Being the highest powered cryocooler we offer at 20 K, the AL630 is very popular in applications that utilize liquid hydrogen as well as high-temperature superconducting magnets. For example, our AL630s are leveraged in several tokamak reactors.

Tokamak reactors utilize nuclear fusion technology rather than fission. Fusion occurs when two atoms slam together to form a heavier atom, such as when two hydrogen atoms fuse to form one helium atom. This is the same process that powers the sun and creates huge amounts of energy—several times greater than fission. Notably, fusion does not produce the highly radioactive byproducts produced with fission.

One of our customers, Thierry Trollier, CEO of Absolut System says of the AL630, “Using Cryomech’s AL630 cryocooler, Absolut Systems manufactures remote helium circulation loops for cooling the superconducting containment field coils used inside tokamaks. We’re working together for the energy transition.”

AL630 Applications: Liquid Hydrogen

Hydrogen is liquefied by cooling it to 20 K. Liquid hydrogen can then be stored in insulated and sometimes actively cooled tanks to be used in numerous applications.

One growing industry is hydrogen-powered equipment. Hydrogen fuel cells and combustion-powered vehicles are becoming increasingly capable, and in some cases liquid hydrogen is used directly as fuel in truck, rail, marine, and rocket engines—NASA has the two largest liquid hydrogen storage tanks in the world.

Hydrogen liquefaction is an energy intensive and expensive process but as time goes on, the liquefaction requirements are continually dropping. The energy density of liquid hydrogen is spectacular, and a major positive side effect of this clean burning fuel is that it has only one byproduct: water.

Diagram of a proton exchange membrane fuel cell
Diagram of a proton exchange membrane fuel cell

Pictured above is a hydrogen fuel cell. These are composed of three main components, and anode, a cathode, and an electrolyte membrane. Fuel cells combine hydrogen and oxygen from the air to produce electricity by using a catalyst to split the hydrogen molecules. Protons then pass through the membrane while electrons move through a circuit, generating current and heat. These are the only byproducts of the reaction besides water, which is generated on the cathode side once the protons, electrons and oxygen eventually combine.

Supporting Clean Energy

The AL630 GM cryocooler plays a key role in the clean energy market, supporting innovation in next-generation nuclear fusion as well as the storage and transport of hydrogen.

As Brent Zerkle, our Director of Prototype for our Cryomech product line, explains, “AL630 cryocoolers are utilized in the liquefaction of hydrogen, which is an important aspect of renewable energy. Hydrogen, when liquefied, becomes a dense and easily transportable energy carrier. Cryocoolers are used to maintain the low temperatures required for the liquefaction process.”

These technologies will play a key role in reducing our planet’s dependence on fossil fuels, and we’re proud that our Cryomech cryocoolers are contributing to that goal.

Discover the Power of Cryogenics

Cryomech cryocoolers can be adapted and integrated into a variety of different types of equipment, enabling you to leverage cryogenic temperatures for a variety of industry-specific applications. If you are looking for 20 K cryogenic solutions, be sure to check out our Cryomech AL630 GM cryocooler.

To find out more, check out our full range of cryocoolers and other products, or contact our sales engineers.