Available for: Dymola 2014 FD01
Dependencies: Modelica Standard Library Version: 3.2
Conversion: None from 1.8.4
- A new information section is included directly in the library, with guidelines on component testbench and cycle initialization.
- Handling of refrigerant properties at the receiver outlet is improved for low or zero-flow simulations.
- In- and outlet pressures, enthalpies and pressures in heat exchanger summary records properly take into account headers, in case those are activated. Previously, only the active heat exchanger part was considered for temperature and enthalpy variables. Enthalpy deviations from previous results are only expected, if heat transfer between headers is possible, temperature may be slighthly different in the two-phase region, due to the additional pressure drop in the headers. This concerns only summary variables, other model variables are unaffected.
- The variability of correction factors for heat transfer and pressure drop in heat exchangers (CF_ ...) has been increased. They are now declared as input variables, which may change over time. As a feature request by many users, this increases the flexibility for user defined modifications. The default behavior of existing models is not expected to change. Manual steps may be required for the conversion of models for pressure drop and heat transfer correlations, which were copied and modified from previous versions of the library. Please, contact support, if you experience problems.
- Display units in the four-value display visualizer are corrected to be consistent with the actual value.
- A static reversible valve , which can be used in architectures that change operation mode.
- A turbine model parametrized with a mass flow lookup table and a efficiency look up table.
- A compressor model with a parametrisation suitable for dynamic compressors. It is parametrised with an isentropic efficiency table and a mass flow table.
- An ORC example experiment has been added to the libary
- A bend component has been added to the library.
- A counterflow internal heat exhanger has been added to the library.
- Visualizers for all working fluids have been added to the library.
- The library contains a new User's Guide and two Tutorials.
- Turbine or the compressor face correct inlet density also for two-phase inlet now. The default characteristics however do not take into account performance deterioration because of liquid at the inlet.
- All heat transfer correlations and pressure drop correlations for pipes have been moved in order to improve user friendliness when working with a combination of different Modelon libraries. Their description and information is updated. Running the included conversion script is necessary for this update.
- The default two phase medium model has been changed from R134a, reference properties by Tillner-Roth to R134a, short form Helmholtz EOS by Span. Its accuracy is slightly lower but still more than sufficient more most applications. The simulation speed is increased significantly with the simpler model.
- Both the receiver and accumulator can be initialized using a liquid level.
- Adding specific interfaces to the heat exchanger models increased replaceability and reusability of the models in a system context.
- The default air model is replaced with one, which is better suited for challenging steady-state initialization. Basically the same assumtions apply except that the new model neglects the liquid volume in case liquid water droplets are transported by the air stream and assumes that they do not influence the specific heat capacity. The previously used model can still be selected from a drop-down list.
- The medium model for CO2 has an improved robustness around the critical point.
- An error in the modified Dittus-Boelter function, which is used in heat transfer correlations for evaporation has been fixed. The change is expected to have an impact on heat exchanger results only, if the secondary side is not limiting the heat transfer.
- A small error in the heat transfer correlation for both evaporation and condensation has been fixed. The change is expected to have an impact on heat exchanger results only if the secondary side is not limiting the heat transfer.
Conversion of user libraries
Automatic conversion of user libraries from version 1.1 is supported using the included conversion script convert_to_1.2.mos located under LibraryName\Resources\Scripts.
Vapor Cycle 1.2 is based on the Modelon base library 2.1 and Modelica Standard Library 3.2.1. It can be combined with Liquid Cooling Library 1.3. and Heat Exchanger Library 1.2.
This library has been tested with:
- Dymola 2015 FD01
- Dymola 2015