Helium-based Stirling cryocooler

Helium-based Stirling cryocooler

Helium-cooled Stirling cryocoolers are low-temperature cooling devices that use helium gas as the working fluid, operating based on the Stirling cycle principle. They are widely used in scientific research, medical, aerospace, and other fields that require low-temperature environments. Below is a detailed introduction to helium-cooled Stirling cryocoolers:

Working Principle

The working principle of a Stirling cryocooler is based on the thermodynamic cycle known as the Stirling cycle. This cycle consists of two isothermal processes and two adiabatic processes. During the isothermal expansion process, helium gas absorbs heat at low pressure, causing its temperature to decrease; in the adiabatic expansion process, the gas continues to expand, further lowering its temperature and generating a cooling effect. Conversely, in the isothermal compression process, helium gas releases heat at high pressure; in the adiabatic compression process, the gas is compressed, and its temperature rises. Through these four processes, the Stirling cryocooler achieves the transfer of heat from the low-temperature part to the high-temperature part, thereby achieving cooling.

Key Components

A helium-cooled Stirling cryocooler is composed of several key components:

  1. Compressor: Used to compress helium, increasing its pressure and temperature.
  2. Expansion Engine: Corresponding to the compressor, the expansion engine allows high-pressure helium to expand at the low-temperature part, lowering the temperature and producing a cooling effect.
  3. Regenerator: In the Stirling cycle, the regenerator is used to exchange heat, ensuring the maximum efficiency of the helium gas in the cycle.
  4. Cold Head: The cold head is where the cooling effect occurs in the Stirling cryocooler, typically including a heat exchanger that absorbs environmental heat and transfers it to the helium gas.
  5. Hot Head: Opposite to the cold head, the hot head is where heat is released, typically including a heat exchanger that transfers heat to the environment.

Performance Features

Helium-cooled Stirling cryocoolers have the following performance features:

  • High Efficiency: Helium’s high thermal conductivity and low viscosity give it excellent cooling efficiency at low temperatures.
  • Stability: Stirling cryocoolers can provide a stable low-temperature environment suitable for applications sensitive to temperature fluctuations.
  • Reliability: Due to their simple mechanical structure and fewer moving parts, Stirling cryocoolers typically have a long service life and low maintenance requirements.
  • Environmentally Friendly: Helium is a non-polluting gas and does not cause environmental damage.

Application Fields

Helium-cooled Stirling cryocoolers are widely used in the following fields:

  • Scientific Research: In low-temperature physics experiments and superconducting material research, Stirling cryocoolers provide the necessary low-temperature environment.
  • Medical: In medical imaging equipment such as MRI, Stirling cryocoolers are used to cool superconducting magnets.
  • Aerospace: In satellites and space probes, Stirling cryocoolers maintain the low-temperature operating environment for sensitive instruments.
  • Industry: In certain industrial processes, such as gas liquefaction and low-temperature testing, Stirling cryocoolers offer necessary cooling solutions.


Helium-cooled Stirling cryocoolers are efficient, stable, and environmentally friendly low-temperature cooling devices, suitable for a variety of applications requiring precise temperature control. With continuous technological advancements, the performance and application range of Stirling cryocoolers are expected to further expand.

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