Online course and simulator for engineering thermodynamics

Refrigeration machine driver taking into account the refrigerant charge

Note

This driver allows one to study a fairly complex problem, that of the adaptation of a refrigeration machine to changes in the outside temperature or the compressor rotation speed.

In this example, the various components are coupled by non-linear equations:

  • First, pressure levels are set by the thermal equilibrium of two phase-change heat exchangers, the evaporator and condenser, which set the saturation temperatures;

  • The compressor sets the volumetric flow of refrigerant (depending on its rotation speed and compression ratio that determine its volumetric efficiency), and thus the mass flow rate (depending on the specific volume of refrigerant at the inlet).

The main parameters of the refrigeration machine, namely the pressure levels and flow-rate, are set by several components strongly coupled whose calculation cannot be done independently.

In addition, we set two additional constraints:

  • we take into account the pressure drops in heat exchangers;

  • sub-cooling is determined by ensuring the conservation of total mass of refrigerant contained in the machine.

Refrigeration machine driver taking into account the refrigerant charge

You will find in the files below the various documents defining the external class:

  • Presentation of the model and instructions for use of the class

  • Java code of the external class

  • extUser.zip or extUser2.zip file containing the class

  • a note explaining the main discrepancies between the results provided by versions 2.71 and 2.72

  • Project and diagram files of an example

  • this driver requires Thermoptim version 2.71 or 2.72. Demo versions can be downloaded from this link.

An example of use of this driver is presented in a page of section "Methodological Guides".

CRC_we_17

frigoAuxNN_ChargeDP08-en.pdf

RefrigOffDesign_2.7.zip

Comparison of the results provided by versions 2.71 and 2.72 of the refrigeration machine pilot in off-design regime

copyright R. Gicquel v2022.1

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