Vuilleumier cycle
Encyclopedia
The Vuilleumier cycle is a thermodynamic cycle
with applications in low-temperature cooling
. In some respects it resembles a Stirling cycle
or engine, although it has two "displacers" with a mechanical linkage connecting them as compared to one in the Stirling cycle. The hot displacer is larger than the cold displacer. The coupling maintains the appropriate phase difference. The displacers do no workthey are not pistons. Thus no work is required in an ideal case to operate the cycle. In reality friction and other losses mean that some work is required.
Devices operating on this cycle have been able to produce temperature
s as low as 15 K
using liquid nitrogen to pre-cool. Without precooling 77 K was reached with a heat flow of 1 W.
The cycle was first patented by Vuilleumier in 1918, and again in Leiden by KW Taconis in 1951.
Thermodynamic cycle
A thermodynamic cycle consists of a series of thermodynamic processes transferring heat and work, while varying pressure, temperature, and other state variables, eventually returning a system to its initial state...
with applications in low-temperature cooling
Cooling
Cooling is the transfer of thermal energy via thermal radiation, heat conduction or convection. It may also refer to:-Techniques:* Air conditioning* Air cooling* Computer cooling* Cryogenics* Conduction * Infrared solar cells* Laser cooling...
. In some respects it resembles a Stirling cycle
Stirling cycle
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 Reverend Dr...
or engine, although it has two "displacers" with a mechanical linkage connecting them as compared to one in the Stirling cycle. The hot displacer is larger than the cold displacer. The coupling maintains the appropriate phase difference. The displacers do no workthey are not pistons. Thus no work is required in an ideal case to operate the cycle. In reality friction and other losses mean that some work is required.
Devices operating on this cycle have been able to produce temperature
Thermodynamic temperature
Thermodynamic temperature is the absolute measure of temperature and is one of the principal parameters of thermodynamics. Thermodynamic temperature is an "absolute" scale because it is the measure of the fundamental property underlying temperature: its null or zero point, absolute zero, is the...
s as low as 15 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
using liquid nitrogen to pre-cool. Without precooling 77 K was reached with a heat flow of 1 W.
The cycle was first patented by Vuilleumier in 1918, and again in Leiden by KW Taconis in 1951.