Stirling Cryocooler

The difference between Refrigerator and Cryocooler

Regenerator

• The Stirling engine was invented by Robert Stirling in 1816. • He was a Scottish minister.• At that time, Stirling engines were recognized as a safe engine that could not explode like steam engines of that era often did.

History of Stirling Cryocooler :

•An bloom of Stirling engine production was brought by J. Ericsson, a Swedish inventor and engineer.

•He succeeded in manufacturing a practical Stirling engine of the 0.5 ~ 5 horsepower class by around 1850.

•The capacity of Stirling engines in those days was inferior compared with Otto engines and diesel engines.

What’s a Stirling cycle?What’s a Stirling cycle?

1->2 constant-temperature compression at TL

2->3 constant- volume heat absorption

3->4 constant- temperature expansion at TH

4->1 constant-volume heat rejection

Schematic of 55 W Stirling Cryocooler

Cooler

RegeneratorHeater supplied

DisplacerPiston

Displacer Flexures

PowerPiston

Power Piston Flexures

Linear AlternatorStationary Magnets Moving Iron

(Courtesy of NASA Glenn Research Center)

Regenerator

One of the regenerator screens

Heater

Flow distributor

Cylinder

Isolation duct

Test Section GeometryTest Section Geometry

Piston

The required characteristic

・ Specific heat is large

・ Thermal conductivity is large

Magnetic material is used

Regenerator

The kind of cryocooler

・ GM Cooler

・ Stirling Cooler

・ Brayton Cooler

・ GM Pulse Tube Cooler

・ Stirling Pulse Tube Cooler

・ JT Cooler

Stirling cryocooler

・ Low vibration

Advantage

・ need not maintain

・ Efficient

ApplicationsApplications

Queries!!!