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2025.2 Release🔗

General availability: Modelon Cloud 2025-OCT-28

Welcome to the 2025.2 release of Modelon Impact! This update delivers powerful new capabilities designed to accelerate multi-case simulation workflows and simplify model setup and analysis. Whether you're comparing design alternatives or optimizing configurations, this release helps you achieve more - with fewer clicks and deeper insights.

In addition to performance enhancements, we've focused on improving usability and the overall modeling experience. Key updates include a streamlined process for creating your first model, a modernized Modelica code editor, enriched parameter dialogs, and a redesigned diagnostics interface for simulation logs.

Highlights🔗

Modelon Libraries🔗

The Modelon library suite has been improved and contains following highlights:

Air Conditioning🔗

  • Improved heat exchanger modelling with updated correlations: A new heat transfer correlation, ChevronMartinSinglePhase, has been introduced to replicate the behavior of the deprecated ChevronPlateHX. This ensures continuity and improved accuracy in models using the updated ChevronPlateLCLCoolantHX.

  • Modernized coolant pipe components for better flexibility: The PipesAndVolumes package now includes StaticPipe, DistributedPipe, LiquidSplit, and LiquidJunction, offering modern replacements for deprecated coolant pipe models. These components support coolant media and enable more robust and maintainable system designs.

  • Greater control over heat exchanger flow configurations: The CoolantRefrigerantHXHorizontal and CoolantRefrigerantHXVertical models now support three flow schemes—cross flow, counter flow, and alternating counter/co-current—allowing users to more accurately represent real-world thermal systems.

  • Enhanced pressure drop modeling with coolant-side headers: Inlet and outlet headers have been added to coolant-side heat exchanger models (TwoPhaseLiquid and LiquidAir), enabling more accurate calculation of total coolant pressure drop (dp_coolant) and improving system-level performance predictions.

  • New LiquidCooling-compatible components for improved media support: CoolantSplitHX and CoolantMixHX have been added to support Liquid Cooling Library coolant media. These new components ensure compatibility with evolving media requirements while maintaining backward compatibility through deprecated versions.

  • More realistic valve dynamics: The internal volume in the check valve model now uses dynamic behavior by default, improving transient response modeling. Users can revert to the previous quasi-static behavior if needed for legacy compatibility.

Breaking changes:

  • Requires conversion script

Electrification🔗

  • Photovoltaic modelling made easier and more robust: Automatic parameter extraction from datasheets, improved usability, and new application examples (including Maximum Power Point Tracking and under-voltage protection) enable faster setup, more realistic simulations, and better support for solar power system design.

  • Smarter and safer DC/DC converter control: New voltage limit features and a built-in Maximum Power Point Tracking (MPPT) controller (using the industry-standard Perturb & Observe algorithm) enhance protection and efficiency in solar applications, while reusable controller templates simplify customization.

Energy Systems🔗

  • New C-rate configuration for batteries and thermal storage: Enables more accurate modelling of charge/discharge behavior, supporting better control strategies and system sizing in energy storage applications.

  • Improved economic modelling clarity and consistency: The default optimization objective is now Total Annualized Cost (TAC), better aligning with long-term planning. Economic variables now include units for clearer interpretation, and parameter dialogs have been updated for easier configuration.

  • Enhanced model transparency and maintainability: Consistent naming across components (e.g., P_ref → P_el_ref), improved documentation, and internal refactoring (including deprecations and renaming) make models easier to understand, modify, and align with published references.

Breaking changes:

  • Requires conversion script

Fuel Cell🔗

  • Improved energy balance handling in flow channels: The energy balance in FuelCell.Pipes has been corrected for cases where useHeatTransfer is disabled. This fix improves the accuracy and consistency of thermal modeling in simplified configurations.

Breaking changes:

  • Requires conversion script

Heat Exchanger🔗

  • Redesigned start value dialogs: All heat exchanger components now feature updated dialogs for defining fluid starting points, including renamed tabs (Initialization → Starting point), clearer parameter groupings, and improved descriptions.

  • Improved initialization structure and flexibility: The parameter howToStart defines how the starting point is applied (e.g., used directly or as a steady-state guess), whatToSet replaces the old initFromEnthalpy and allows selecting which fluid properties to define (e.g., pressure + temperature, superheat, subcooling), and all start values are now grouped in a structured startingPoint record (e.g., startingPoint.p, startingPoint.T), improving clarity and consistency across components. Users can now define starting conditions using combinations such as pressure + temperature, vapor quality, superheat, subcooling, dew/bubble line temperatures—offering greater flexibility, especially for refrigerants.

Breaking changes:

  • Requires conversion script

  • Impact on plate-type heat exchangers: Due to a bug fix in two-phase channel modelling, refrigerant-based plate heat exchangers may show increased flow resistance when condensing and decreased resistance when evaporating. Other geometries and single-phase cases are unaffected.

Liquid Cooling🔗

  • Faster and more scalable liquid network simulations: New model simplifications—enabled via temperatureFromUpstream and positiveFlow—allow significant simulation speed-up without compromising accuracy. These can be applied globally using the Settings_LCL component, making it easier to optimize performance in large-scale cooling systems.

  • Advanced thermal storage modelling: New StratifiedTank and StratifiedTankInternalHX models support simulation of thermal energy storage with stratification and internal heat exchange. Included examples demonstrate realistic use cases such as integrated heating and cooling loops.

  • Improved system visualization: A new mass flow rate-based visualization option has been added to all LCL components, complementing existing temperature and pressure views. This enhances interpretability of flow behavior in complex networks.

  • Vehicle thermal management example system: A complete coolant network system model has been added, demonstrating thermal management of a vehicle with components like cabin, battery, charger, inverter, and motor. This example helps users quickly understand how to build and simulate full-system cooling architectures.

  • Easier model analysis with summary records: Summary records have been added to all major component categories (Volumes, SplitsAndJoins, Valves, etc.), simplifying post-processing and reporting of simulation results.

  • Enhanced flow direction visualization: The dynamic flow arrowhead now scales with mass flow rate and updates across all components. Users can configure its displacement range using m_flow_min and m_flow_max parameters for clearer visual feedback.

Breaking changes:

  • Requires conversion script

Modelon Base🔗

  • Major simulation speed-up for fluid networks: New model simplifications in Modelon.ThermoFluid—including upstream temperature propagation and equation reduction under positive flow assumptions—significantly improve performance for large, component-rich fluid networks like coolant systems or gas-based models.

  • New stratified tank models for thermal energy storage: StratifiedTank and StratifiedTankInternalHX enable accurate simulation of thermal layering and internal heat exchange, supporting advanced heating/cooling system design with included example use cases.

  • Improved initialization and usability in heat exchangers: Updated parameter dialogs and new options for defining starting points (e.g., pressure + superheat/subcooling) enhance model setup flexibility, especially for two-phase fluids.

  • Enhanced robustness and diagnostics: New assertions detect incorrect flow direction assumptions, helping users avoid mass/energy balance errors. Smooth interpolation in pump torque tables improves solver performance and supports analytic Jacobians.

Breaking changes:

  • Requires conversion script

  • Manual equation update for custom fluid connectors: If you’ve created equation-based component models that introduce a fluid connector and assign internal variables by equation (e.g., custom components or copies of Modelon Base Library components), you must add one extra equation per fluid connector instance to ensure compatibility with the updated connector structure in Modelon Base Library 6.0.

Thermal Power🔗

  • Redesigned start value dialogs: All components with fluid (refrigerant or air) now feature updated dialogs for defining fluid starting points, including renamed tabs (Initialization → Starting point), clearer parameter groupings, and improved descriptions.

  • Improved initialization structure and flexibility: The parameter howToStart defines how the starting point is applied (e.g., used directly or as a steady-state guess), whatToSet replaces the old initFromEnthalpy and allows selecting which fluid properties to define (e.g., pressure + temperature, superheat, subcooling), and all start values are now grouped in a structured startingPoint record (e.g., startingPoint.p, startingPoint.T), improving clarity and consistency across components. Users can now define starting conditions using combinations such as pressure + temperature, vapor quality, superheat, subcooling, dew/bubble line temperatures—offering greater flexibility, especially for refrigerants.

  • Support for distributed components: For components with internal distributed states (e.g., pipes, heat exchangers), both inlet and outlet starting points must be defined.

Breaking changes:

  • Requires conversion script

Vapor Cycle🔗

  • Redesigned start value dialogs: All components with refrigerant or air now feature updated dialogs for defining fluid starting points, including renamed tabs (Initialization → Starting point), clearer parameter groupings, and improved descriptions.

  • Improved initialization structure and flexibility: The parameter howToStart defines how the starting point is applied (e.g., used directly or as a steady-state guess), whatToSet replaces the old initFromEnthalpy and allows selecting which fluid properties to define (e.g., pressure + temperature, superheat, subcooling), and all start values are now grouped in a structured startingPoint record (e.g., startingPoint.p, startingPoint.T), improving clarity and consistency across components. Users can now define starting conditions using combinations such as pressure + temperature, vapor quality, superheat, subcooling, dew/bubble line temperatures—offering greater flexibility, especially for refrigerants.

  • Support for distributed components and capillary tubes: For components with internal distributed states (e.g., pipes, heat exchangers), both inlet and outlet starting points must be defined. Capillary tubes now support defining inlet by pressure + subcooling and outlet by pressure + enthalpy drop.

Breaking changes:

  • Requires conversion script

Vehicle Dynamics🔗

  • Expanded suspension modelling flexibility: New four- and five-link push/pull rod linkage templates with rockers have been added under Suspensions.Linkages.Independent.Templates, enabling more detailed and customizable suspension configurations. Variants of double wishbone, four-link, and five-link linkages without external springs/dampers are also available, with both steerable and non-steerable suspension templates—supporting a wider range of vehicle architecture use cases.

  • Improved documentation clarity: Descriptions in Vehicles.Chassis.Suspensions.Interfaces.Base4 have been updated to correct wheel position labelling and hub numbering. These changes improve model readability and reduce the risk of misinterpretation, without affecting simulation results.

Buildings Library🔗

A new Buildings Library package is now available for Modelon IMPACT Cloud users. This package includes:

  • Buildings Library 12.1.1 is now available in Modelon IMPACT.
  • For full release notes, visit: Buildings Library Release Notes 12.1.0
  • Note: Compared to version 12.1.0, the 12.1.1 version also includes a fix for issue #4321

Build🔗

Streamlined model creation🔗

Getting started is now simpler and faster, with improvements to the package browser and model creation workflow:

  1. Automatic package creation when your first model is added

  2. New creation shortcuts for packages, models, and classes

  3. Editable package names – names no longer get truncated

Parameter descriptions🔗

Parameter descriptions are now displayed inline by default, giving you a quicker overview.

The old behavior (descriptions shown as tooltips) can still be enabled via the Show description toggle.

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Model Code View - modern Modelica code editor🔗

We’ve upgraded the editor’s core technology to provide a more powerful and intuitive coding experience:

  • Command palette (F1) – quick access to actions such as fold/unfold annotations

  • Minimap – bird’s-eye view of your entire code file

  • Enhanced search & replace - See all matches instantly

  • Open in VS Code (browser-based ) – one-click launch directly from the interface

  • Multi-cursor editing – edit multiple locations at once

Analyze🔗

Experiment Builder - Dedicated view for experiment setup🔗

The Experiment Setup View has been improved and reached General Availability. Users can easily setup multi-run experiments and quickly do a study of the design space. New functionalities include:

UI support to set-up parameter sweeps with extended support for choices

Activate the Parameter sweep UI-toggle to create a multi-run experiment by defining the range of a sweep and/or specify a set of choices. The support for choices include Integer, String, Boolean, and Enumerations. This makes it possible to quickly setup experiments and compare model configurations such as controller types and initialization options.

Explore the Design Space with Statistical Experiments

Easily generate design studies using statistical sampling algorithms:

  • Specify how many simulation cases you want
  • Choose parameter distributions (Normal, Uniform, Beta)
  • Use advanced sampling algorithms like Sobol and Latin Hypercube to get broad and efficient coverage of your design space

Save time and reduce errors when configuring complex design studies.

Speed Up Simulations (with Productivity Add-on)

Run large experiments faster with support for parallel execution, cutting down overall simulation time and boosting productivity.

Control Data Volume with Smart Output Filters

Large experiments no longer have to mean large result files:

  • Filter results by views, favorites, components, or variables

Model Debug - improved diagnostics reporting🔗

The simulation log has been redesigned for clarity and efficiency:

  • Summary section – counts of warnings and errors, grouped by type and source

  • Detailed section – root-cause information with structured output

    • The log view shows the first and last 25 warnings/errors for easier navigation

    • Full logs remain available via artifacts

    • Now includes ModelicaError and ModelicaWarning for better model-specific debugging

  • Improved formatting – warnings and errors are clearer to read

Other diagnostics improvements:

  • Improved diagnostics in case Assert fails during simulation​​

Modelica compiler🔗

  1. Significantly improved compilation performance for certain models that requires evaluation of external functions during the compilation.

For details, see the release notes for Optimica Compiler Toolkit.

Visualization Tools: Redesigned Diagram-Layer Plotting🔗

We are happy to announce that the new version of Diagram plotting view has reached General Availability, giving the user a modern and dedicated view for analyzing results. The framework is now unified with the Analysis view and is more powerful and intuitive with new plot types and a new way to select compare and select result.

The new diagram mode comes with following new functionality and improvements:

Additional plot types

The user can choose from using following plot types:

  • Line chart - for display of results over time (default option for display of results from dynamic simulations)
  • Stacked area chart - to understand the breakdown of groups over time (useful for energy applications)
  • Scatter chart - to compare and show relationship between numeric values (default option for display of results from steady-state simulations)

Synchronized zoom across plots

To increase productivity when working with multiples plots, a global time slider, where you can set a range, has been introduced that enables synchronized zoom across plots.

The new time slider support:

  • Synchronize the x-axis on all plots by dragging the endpoints
  • Set the current time-point by either enter the time-point or drag the cursor
  • Reset the default x-axis zoom-level by clicking the reset button

Multi-select of results

To make it easier to compare a result to previous simulations a new toggle has been introduced that separate the result selection into:

  • Single result - for selection of a single result to be shown in plots
  • Multiple results - for comparison between two or more results

Visualization Tools: Live Plotting of Running Simulations🔗

You can now visualize simulation results as they run in both Analyze and Diagram result mode. Results will appear automatically, and any connected line plots will update in real time. This provides faster feedback and allows you to monitor trends or detect issues early in the process.

Note

This feature is currently supported for single-case dynamic simulation. It does not apply to multi-simulations, optimizations, or other analysis types.

Visualization Tools: Improved Line Plots for Steady-State and Single-Point Simulations🔗

Line plots for steady-state or single-point dynamic simulations (where start and end time are the same) now include: - Automatic markers to highlight data points - Dashed lines to clearly differentiate them from full dynamic results

These enhancements improve clarity and make it easier to visually compare different simulation types.

Platform information🔗

Execution environment🔗

This release includes the following execution environments.

Note, self-managed only include the latest version of the execution environment.

Execution environments v2025.2 v2025.1
Optimica Compiler Toolkit v1.64 v1.56
   Modelica compliance v3.4 of Modelica Language specification1 v3.4 of Modelica Language specification1
   FMU compliance v2 (default) and v1 v2 (default) and v1
Operating system Ubuntu v22.04 Ubuntu v22.04
Python environment v3.11 v3.11
C compiler GCC v11.4 and glibc v2.35 GCC v11.4 and glibc v2.35

1 See Optimica Compiler Toolkit User's guide for further information about Modelica compliance and limitations.

Libraries🔗

This release includes the following library versions for Modelon Cloud. Columns indicate the release when a version was made available.

Libraries 2025.2 2025.May 2025.1
AirConditioning 2.0.0 1.30.0 1.29.0
AirConditioningAdapters 2.0.0 1.30.0 1.29.0
Electrification 2.1.0 2.0.0 1.13.0
EnergySystems 1.4.0 1.3.0 1.2.0
FuelCell 2.0.0 1.21.0 1.20.0
HeatExchanger 4.0.0 3.0.0 2.14.0
Hydraulics 4.24.0 4.23.0 4.22.0
IndustryExamples 1.8.0 1.7.0 1.6.0
LiquidCooling 3.0.0 2.15.0 2.14.0
Modelon 6.0.0 5.0.0 4.6.0
ThermalPower 3.0.0 2.0.0 1.29.0
VaporCycle 4.0.0 3.0.0 2.14.0
VehicleDynamics 4.8.0 4.7.0 4.6.0

Breaking Changes🔗

Visualization🔗

Following functionality is not longer available, 3D plots and custom color selection.

Proposed actions: For 3D plots, it's recommended to instead use the notebook or Excel plotting capabilities.

Execution environment🔗

As a result of improving the Modelica compiler diagnostics, additional error checks have been introduced that follow stricter the Modelica specification. Following improvements has been made

  1. Changed some parsing rules to be more compliant with the specification. As a result some invalid grammar is no longer accepted by the compiler. E.g. a - -b and {a = b}.

Proposed actions: Rewrite a - -b to a - (-b) and {a = b} to {b}.

  1. Added error check for when constants and parameters are incorrectly assigned in the algorithm section of functions.

Proposed actions: Initialize constants and parameters using binding equations instead of assigning in the algorithm section. E.g. constant Real c = 1 instead of: 

function f
    ...
    constant Real c;
algorithm
    c := 1;
    ...
end f;

Libraries🔗

2024.2 library distribution🔗

The 2024.2 distribution of libraries has been removed from Modelon Cloud. The following library versions are therefore not longer available on Modelon Cloud.

Libraries 2024.2
AirConditioning 1.28.0
AirConditioningAdapters 1.28.0
AircraftDynamics 1.11.0
Electrification 1.12.0
EnergySystems 1.1.0
EnvironmentalControl 3.17.0
FuelCell 1.19.0
FuelSystem 5.6.0
HeatExchanger 2.13.0
Hydraulics 4.21.0
IndustryExamples 1.5.0
JetPropulsion 2.8.0
LiquidCooling 2.13.0
Modelon 4.5.0
ThermalPower 1.28.0
VaporCycle 2.13.0
VehicleDynamics 4.5.0

See Library Conversion for how to migrate workspaces to newer library versions.

We hope you like the new functionality and improvements and look forward to your input!

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