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Fig.1 Schematic diagram of a Stirling cooler. The system has one piston at ambient temperature T a and one piston at low temperature T L. The basic type of Stirling-type cooler is depicted in Fig.1. It consists of (from left to right): a piston; a compression space and heat exchanger (all at ambient temperature T a) a regenerator; a heat exchanger
Stirling cryocoolers are able to "lift" heat down to −200 °C (73 K), which is sufficient to liquefy air (specifically the primary constituent gases oxygen, nitrogen and argon). They can go as low as 40–60 K for single-stage machines, depending on the particular design.
Pulse tube cryocoolers are used in niche industrial applications such as semiconductor fabrication and superconducting radio-frequency circuits. [1] They are also used in military applications such as for the cooling of infrared sensors. [2] In research, PTRs are often used as precoolers of dilution refrigerators.
As a consequence of closed-cycle operation, the heat driving a Stirling engine must be transmitted from a heat source to the working fluid by heat exchangers and finally to a heat sink. A Stirling engine system has at least one heat source, one heat sink and up to five heat exchangers. Some types may combine or dispense with some of these.
The first experimental machines were built in the 1990s, when (commercial) cryocoolers became available, capable of reaching a temperature lower than that of liquid helium and having sufficient cooling power (on the order of 1 Watt at 4.2 K). [6] Pulse tube coolers are commonly used cryocoolers in dry dilution refrigerators.
It was originally developed around 1900 for the twin-cylinder Lanchester car engine where it allowed perfect balancing of the inertial forces on both pistons. A current example of its use is on beta type-Stirling engines; the drive's complexity and tight tolerances, causing a high cost of manufacture, is a hurdle for the widespread usage of this drive.
The Stirling cycle is a thermodynamic cycle that describes the general class of Stirling devices. This includes the original Stirling engine that was invented, developed and patented in 1816 by Robert Stirling with help from his brother, an engineer .
The mechanism of operation of the engine can be described by the laws of quantum mechanics. Quantum refrigerators are devices that consume power with the purpose to pump heat from a cold to a hot reservoir. In a reciprocating quantum heat engine, the working medium is a quantum system such as spin systems or a harmonic oscillator.