Vuilleumier cycle

The Vuilleumier cycle is a thermodynamic cycle, which was patented in 1918 by its inventor Rudolph Vuilleumier. The process is similar to the process of a Stirling engine is a thermally regenerative gas cycle process. In contrast to the Stirling process of Vuilleumier process but is used in counter-clockwise heat pumps and chillers.

In a Vuilleumier pump similar to the Stirling engine are the components:

  • Displacer
  • Regenerator
  • Flywheel

Used. In Stirling there is the working piston to do so. Switched to two Stirling engines together, it can be set as the first combustion engine, which is operated by means of a thermal energy source, and the second as a working machine, namely a mechanically driven heat pump.

Vuilleumier the pump consists of two serially connected compressor elements ( displacer ) with three temperature levels. The compressor elements separate a constant gas volume in three oscillating changing partial volumes V1, V2, V3. The volumes V1 and V3 take on heat, the volume V2 gives off heat. Between V1 and V2 and between V2 and V3 is in each case a regenerator R1, R2, and a compressor element K1, K2. The individual phases of the cycle are as follows:

  • Phase I: The displacer K1 minimizes the volume V1, the regenerator R1 assumes its maximum amount of heat to the volume V2 reaches a maximum, minimizes the volume of the displacer K2 V3 slightly phase shifted to the minimum volume V1. The temperature in V3 is higher than the outside temperature at the cooling surfaces and are thereby heat energy. The temperature in V3 cools.
  • Phase II: the volume V3 is reduced by the heat extraction, the piston increases the volume V1 K1, which is now heated by the regenerator R1 and an external heat source. The volume V3 is minimal.
  • Phase III: The volume V3 is increased by the negative pressure produced by the regenerator and R2, the gas cools in V3 and absorbs heat from the surroundings. The volume V2 is minimal.
  • Phase IV: The piston K1 moves upward, the volume V2 is increased, the volume V1 decreases.

Apply the following physical connections:

  • In Phase I and II, heat energy is transferred from the volume V 2 to the outside ( heat of compression ).
  • The total pressure is constantly increasing in phase I and II ( isothermal pressure increase ).
  • In Phase III and IV, heat energy is absorbed by the volume V1 and V3 (expansion cooling).
  • The total pressure decreases steadily in Phase III and IV ( isothermal expansion ).

Areas of application

The Vuilleumier heat pump has been built for very specific purposes, for example for cooling of infrared sensors or to catch cooling of fishing trawlers. At present some interesting research work in this field, as new materials greatly expand the application range of this heat pump.

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