Vuilleumier cycle

Branches

Equilibrium / Non-equilibrium

State
Equation of state Ideal gas Real gas State of matter Equilibrium Control volume Instruments
Processes
Isobaric Isochoric Isothermal Adiabatic Isentropic Isenthalpic Quasistatic Polytropic Free expansion Reversibility Irreversibility Endoreversibility
Cycles
Heat engines Heat pumps Thermal efficiency

System properties

Note: Conjugate variables in italics

Functions of state
Property diagrams Intensive and extensive properties
Temperature / Entropy (introduction) Pressure / Volume Chemical potential / Particle number Vapor quality Reduced properties
Process functions
Work Heat

Material properties

Property databases

Specific heat capacity

c=

$T$	$\partial S$
$N$	$\partial T$

Compressibility

\beta =-

$1$	$\partial V$
$V$	$\partial p$

Thermal expansion

\alpha =

$1$	$\partial V$
$V$	$\partial T$

Equations

Potentials

Internal energy
$U(S,V)$
Enthalpy
$H(S,p)=U+pV$
Helmholtz free energy
$A(T,V)=U-TS$
Gibbs free energy
$G(T,p)=H-TS$

History
Culture

History
General Heat Entropy Gas laws "Perpetual motion" machines
Philosophy
Entropy and time Entropy and life Brownian ratchet Maxwell's demon Heat death paradox Loschmidt's paradox Synergetics
Theories
Caloric theory Theory of heat Vis viva ("living force") Mechanical equivalent of heat Motive power
Key publications
"An Experimental Enquiry Concerning ... Heat" "On the Equilibrium of Heterogeneous Substances" "Reflections on the Motive Power of Fire"
Timelines
Thermodynamics Heat engines
Art Education
Maxwell's thermodynamic surface Entropy as energy dispersal

Scientists

Book:Thermodynamics

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 work—they 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 temperatures 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. In March 2014, the Vuilleumier Cycle was tested in application with updating conventional HVAC (heating, ventilation, and air-conditioning) systems by utilizing the cycle's proposed thermodynamic process of moving heat energy, and having results of increased output efficiencies coupled with a reduced carbon footprint.^[1] This work was completed by ThermoLift, a company based out of the Advanced Energy Research and Technoloy Center at Stony Brook University, with collaboration from the US Department of Energy and the New York State Energy Research and Development Authority (NYSERDA).^[2]

External links

Wikimedia Commons has media related to Vuilleumier cycle.

References

Experimental techniques in low-temperature physics, Guy Kendall White, Philip J. Meeson, Oxford University Press, 2002, p. 30 Link
Energy Savings Potential and RD&D Opportunities for Non-Vapor-Compression HVAC Technologies, U.S. Department of Energy, William Goetzler, Robert Zogg, Jim Young, Caitlin Johnson, Navigant Consulting, Inc. March 2014 Link

Thermodynamic cycles

External combustion

Without phase change (hot air engines)	Bell Coleman Brayton / Joule Carnot Ericsson Stirling Stirling (pseudo / adiabatic) Stoddard

With phase change	Kalina Hygroscopic Rankine (Organic Rankine) Regenerative

Internal combustion

Mixed

Refrigeration

Uncategorized

This article is issued from Wikipedia - version of the 11/7/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.