Cryocoolers play a critical role in modern industries, from space exploration to medical imaging. But how do they work, and why are they essential for cryogenic systems?
What is a cryocooler?
A cryocooler is a mechanical refrigeration system designed to reach cryogenic temperatures (typically between 10 K and 120 K) without the need for liquid cryogens, commonly used in medical, aerospace, and industrial applications.
Generally, cryocoolers are expected to be lightweight and present a small volume, as well as cool down quickly and with no vibrations. Finally, the most sought-after systems will present easy and spaced maintenance needs.
How does a cryocooler work?
Most cryocoolers work using cryogenic fluids, which are circulated by a series of moving parts, generating a thermodynamic cycle. In general, there are two main ways in which cryocoolers operate:
At the same time, there are two basic ways in which cryocoolers work:
Regenerative systems
Regenerative systems use flow and pressure in an oscillating manner in order to attain the desired refrigeration. In other words, these systems often use pressure oscillators but not displacers.
Recuperative systems
Recuperative systems work by moving fluids around a loop at pre-established high and low pressures. To achieve this, the fluid is compressed at room temperature and then cooled using a heat exchanger. Afterwards, it is expanded at low temperature depending on the system requirements.
This type of cryocoolers need reciprocating pistons or unidirectional compressors without valves. Maintenance also means the use of oil-removal tools, to guarantee oil remains don’t freeze. Other parts include orifices, capillaries and valves or expansion engines, in order to generate the right low-temperature expansion.
Keep reading: Cryogenic tanks: 4 criteria you should consider when picking them
Key components of a cryocooler
As explained above, there are different types of cryocoolers, which present their own specific needs in terms of tools and technical parts. However, there are at least two main parts that are typically used in cryocoolers:
Heat exchangers
These components cool down cryogenic fluids, a process that typically occurs at constant pressure. In addition, heat exchangers can be either regenerative or recuperative.
Regenerators
Regenerators are made of granular particles or porous materials that allow gas flow. As a result, heat can be both stored and released within the system.
Applications of cryocoolers
- Liquefaction of gases. Cryocoolers are widely used for gas liquefaction, as they enable easier and more efficient transport and storage. For example, gases such as nitrogen, oxygen, hydrogen, and natural gas require cryogenic conditions to be liquefied.
From ships powered by liquid hydrogen to gas transportation and the many applications of liquid oxygen, the uses of liquefied gases obtained by cryogenic temperatures are increasing. Accordingly, the cryogenic equipment market is predicted to grow at a CAGR of 6.4% between 2020 and 2025, driven by Increasing demand for industrial gases and investments in LNG infrastructure, according to Markets and Markets.
- Moreover, the military and space industries use cryocoolers for various operations, including cooling infrared sensors in satellites and missile guidance systems.
- The medical sector uses cryocoolers in MRI systems
- Superconducting electronics also employ cryocoolers
Different types of cryocoolers
As explained above, there are two main ways in which cryocoolers work (regenerative or recuperative systems). From those two chief working systems, a number of different types of cryocoolers have been developed:
- Heat exchangers
- Pulse tube cryocooler, which use sudden expansion and release of refrigerant gaseous substances
- Helium cryocooler
- Polycold cryocooler
- Stirling cryocooler, which consists of the following elements: a heat exchanger, a both a compression and expansion space, a piston, and a regenerator.
- Gifford – McMahon refrigerators. These are commonly used in MRI systems, and typically use helium as the working fluid.
- Joule – Thomson cryocoolers, which are also called Linde-Hampson coolers as they were invented by Carl von Linde and William Hampson. The sizes for this system can vary tremendously, from tiny to large scale, depending on their use. For instance, liquefied natural gas (LNG) will typically need a large scale system, which can employ multiple parts such as a compressor, a counterflow heat exchanger, a JT valve, and a reservoir.
The diverse types of cryocoolers speak of multiple possibilities in order to generate cryogenic temperatures needed for many purposes across different industries.
Are you searching for the right cryocoolers for your cryogenic equipment?
At Cryospain, we execute tailor-made cryogenic engineering systems, offering our expertise and know-how in order to generate cryogenic facilities and equipment projects, and guaranteeing efficient solutions tailored to the specific needs of our clients.
We also design and manufacture complete chassis and cryogenic equipment following the specific characteristics requested by our clients. As part of our designing process, we make sure all the system’s components are completely and compactly built in, thus allowing easy operations.
As part of these tailored cryogenic engineering infrastructures, we include the most adequate cryocoolers for each project when they’re needed or demanded.
Get in touch with us and learn more about our engineering solutions for cryogenic systems.
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