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2024.1 Release🔗

Release 2024.1 (version 2.95.1)
General availability: Modelon managed 2024-February-27 | Customer managed 2024-March

Welcome to the 2024.1 release of Modelon Impact. For the 2024.1 release, our focus has been on making workspace sharing effortless, giving users more control at upgrades, and strengthening the Excel integration.

Selected Highlights🔗




Build: Libraries🔗

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


Hydrogen tank design – Support for new scenarios and improved usability

  • Support for new scenarios such as dynamic fill, drain and storage of a horizontal tank with the new Improved hydrogen storage tank model
  • More accurate simulations with new heat transfer convection models
  • Easier to get started with new tutorials and improved documentation of models and workflows

Thermal Management and Fuel – Analyze the weight of aircraft thermal management systems and import of CAD data

  • Analyze the weight of the thermal management system
  • Directly import CAD geometry with new Fuel tank pre-processing app

Propulsion and power – Better support for supersonic flight conditions and more accurate simulations

  • New variable geometry nozzle model to better support fighter jets at supersonic conditions
  • Within jet engines, efficiencies in the turbine and compressor are penalized and computed more accurately.

The new fuel tank pre-processing app will allow finer mesh and makes updates faster!


Thermal management – Improved accuracy, performance and robustness

  • Improved Regenerated lookup tables for CO2 SBTL medium
  • System/cycle models enhancements
  • Correlations for heat transfer and pressure drop in channels
  • Receiver features for outlet quality and desiccant volume

Vehicle dynamics – Export and drive your Modelon Impact vehicle model in real-time in rFpro

  • Export your vehicle model from a template in VehicleDynamics library into rFpro (a driving simulation software)

Coupling between Modelon IMPACT and rFPro to test your model in real-time driver-in-the-loop!

Energy, Air conditioning and Refrigeration🔗

Energy System Optimization – New library for Dispatch optimization of hybrid energy systems and convenient economic analysis workflow

The Energy Systems Library is a new Modelica-based library designed to model and plan industrial to utility-scale integrated energy systems. This library allows users to evaluate integration of various energy demands, supply sources and storages and optimize the techno-economic result over time, considering technical limitations and boundary conditions.

Power Plant Simulations – Improved user friendliness and new components

  • Direct Air Capturing improvements and new rotating bed adsorber model two-phase/two-phase heat exchanger
  • New sensors for measuring steam quality and superheat

Residential Heat Pumps – Improved support for traditional fin-on-tube heat exchangers

  • New correlation for air-side moisture condensation
  • Improved flexibility for routing configuration

Refrigeration – New commonly used refrigeration type heat exchanger models

  • New skin condenser model
  • New sawtooth wire-on-tube heat exchanger model

Compute and optimize profitability of hydrogen-blending in existing power plant in the new Energy Systems Library!

Cross-industry improvements🔗

Thermal management – Usability improvements, new sizing functionality and robustness

  • Vapor Cycle, Liquid Cooling and Heat Exchanger Library: UX improvements leverage use of stickies, views, experiments and parameter UI
  • Liquid Cooling Library: Heat exchangers, pump and closed loop example with steady state simulation
  • Vapor Cycle Library: Support for ASHRAE data format to parameterize compressors
  • Heat Exchanger Library: fixes related to mass conservation in closed cycles

Improved capabilities for sizing and added mass estimation of Liquid cooling cycle, including new views!

Electrification – Improved ease of use, new sizing functionality, and more application examples

  • Sizing workflow (dimensions and mass), with examples for electric machines, battery packs, and cables
  • Simplified electrical connectors, that does not require specifying a ground for easier
  • New application examples, including a photo-voltaic array and a linear actuator
  • A more scalable machine loss model (equation based)

Sizing of battery pack, electric motor, and cables. With new connectors that are more robust and easy to use.

Build: Model Builder🔗

Model Import - Improved FMU import and compliance🔗

The FMI-import functionality has been improved. FMUs that are imported into Modelica are easier to version-control. This has been enabled by an update of how the unique ID is generated at FMU import. Note, this update does only affect import of new FMUs.

In the FMU import dialog you will now find the option "Overwrite existing FMU" with which existing FMUs with the same name are overwritten by default. This helps you to integrate new versions of an FMU model more easily.

With the OS update to Ubuntu 20.04 (from CentOS 7.4), the FMU import compliance has been improved and supports now import of FMUs from RHEL 7.x and Ubuntu 18 and 20. See breaking changes for how FMU export is affected.

Model Debug🔗

Improved Error-Messages:

  • Showing the source (stack trace) of assert
  • Improved message for invalid inputs to Range operator
  • Better error messages for non-valid classes.

Improved Compilation Log:

  • Removal of non-actionable warning messages makes the logs less cluttered and easier to read.

Improved Diagnostics Tools:

  • Easier to navigate html diagnostics - blockInfo.html now contain hyper-links to respective referenced block in initBlt.html and blt.html

Note, see Diagnostics Guide for how to enable run-time diagnostics.

Library packaging🔗

OpenSSL 3.0 upgrade of SEMLA. SEMLA (Standardized Encryption of Modelica Libraries and Artifacts) has been updated to OpenSSL 3.0. The updates have also been propagated upstream to its open-source repository at SEMLA Repository.

Analyze: Solver🔗

Access to earlier solvers for extended backward compatibility🔗

Access to earlier solvers for extended backward compatibility. To give users more control of updates, it’s now possible to stay on a previous version of the execution environment. The execution environment includes:

  • A specific version of OCT including compiler, simulation, and optimization Python framework.

This gives the user an option to choose when to migrate to a newer version. The versioned execution environment is set at login. The choice will be remembered at the next login. For more information, see Execution environment.

Further information on update and deprecation strategy in Update strategy.

Note, the execution environment is separated from the Modelica libraries, making it possible to freely combine execution environment with libraries. Since the 2023.2 release, it’s possible to choose an older version of a library in the Workspace Management app.

Analyze: Modelica Compiler🔗

  • Faster compilation due to an update to a newer version of gcc, see section OS below.
  • Improved support for compilation of expandable connectors with inputs and outputs.
  • Support for negated alias pair (e.g., x=-x). The symbolic framework will automatically transform this equation to x=0. See release notes in OPTIMICA Compiler Toolkit (OCT) User Guide for further information.

Analyze: OS🔗

The underlying Operating System has been updated to Ubuntu v20.04 (from CentOS 7.4). This results in the following improvements for the users:

  • Improved compliance of FMU import (see section Model import).
  • Faster compilation due to an update of gcc (v9) from gcc (v4).
  • Upgrade to Ubuntu v20.04 (from CentOS 7.4).

Analyze: Experiment Builder🔗

Enhanced support for execution settings:

  • Easier to specify a fixed step size. The step size is now displayed together with ExplicitEuler.
  • Toggle to enter output points or interval - Values are converted into each other.
  • Steady-State execution option is now always enabled.
  • Support to duplicate experiments of read-only experiments.
  • Spinners are shown when experiments are loading.
  • The option store_event_points is now visible by default. Set store_event_point to false to reduce the result size for simulations including events.
  • Easier to set solver settings as available options are displayed in a list.

Collaborate: Workspace🔗

Workspace Configuration🔗

The workspace configuration app has been improved:

  • New Libraries page to show, import, and delete user-installed Libraries. In the new “Libraries” page, a user can:

    • Import a third-party Modelica library or a specific version of a Modelon library that is not available on Modelon Impact.
    • Get an overview of all imported user-installed libraries.
    • Delete user-installed libraries to free up disk space.
  • New Published page to manage published workspaces.

  • Export a Project from the context menu in Projects page. This was previously only possible from within a workspace in Modelon Impact.

Collaborate: Sharing Tools🔗

App Mode🔗

A Base or Pro user can now publish a pre-configured model as App Mode. This enables a cloud-native way of sharing models with non-simulation experts that get access to a simplified experiment view. The support of sharing through a web-link removes previous manual import and export steps.

The publisher of the app-mode will also be able to:

  • Delete the published workspace.
  • Update the published workspace while keeping the generated link intact.

When the receiver clicks on a link to a shared app-mode the workspace is cloned and imported into the receiver’s user space.

Workspace Publish🔗

A Workspace can now be published and shared with an organization with one click. This simplifies sharing as there is no need to set up version control or manually import and export a workspace. Access to the shared workspace is restricted to the group of registered users in the same organization (tenant).

When a workspace is published Modelon Impact takes a copy of the existing workspace and uploads it to a service and makes it accessible by a web-link.

With the new workspace publishing functionality, you will be able to:

  • Share a workspace (full/app mode) with everyone in your organization.
  • Choose if the workspace should include results or not.
  • Share a large workspace, the workspace can be larger than 100 MB.
  • Update the published workspace. The receiver decides if they want to upgrade to the latest version.

Collaborate: Integration Tools🔗


The Modelon Impact Excel add-in has seen major improvements and new functionality:

Support for more analysis

  • Steady-state simulation – support to run steady-state simulations
  • Custom analysis – support to run custom function analysis
  • Dynamic simulation – support to fetch and plot the full result trajectory

Easier setup

  • View units of inputs and outputs
  • UI support for selecting variables to use as input and output
  • Viewing and modify simulation options

Learn how to get started with Impact Excel Add-in here.

The FMI Toolbox has now a connector to Modelon Impact that enables synchronization of the generated FMU with the Modelica model in Modelon Impact. Note, FMI Toolbox is a separate Modelon product.

Python Client🔗

New functionalities include improved support for workspace management:

  • Support to rename a workspace
  • Support for filtering workspace based on name, app_mode, and sharing_id
  • Support for publishing a workspace
  • Support to fetch updates from a published workspace
  • Support for exporting publishing app mode workspaces

See impact-client-python/tags for further information.

JavaScript Client🔗

The JavaScript Client library has been completely rewritten to support the latest changes in the underlying APIs. New functionality includes:

  • Typescript API including type definitions generated from the Modelon Impact REST API.
  • Node.js support.
  • Unit tests and integration tests.
  • Support for access via API-key usage from outside the Modelon Impact platform.
  • Example scripts
  • Fallback API to unlock the complete REST API and only use impact-client-js for authentication, via Client.get(),, Client.put(), and Client.delete().
  • New methods to get model executable information for simulations.

See impact-client-js/releases for further information.


Collaborate: Cloud Access🔗

Customer managed🔗

A new simplified packaging of customer managed is available. Customer managed is for organizations that have opted to install Modelon Impact on their server, physical, or virtual, as an alternative to the software-as-a-service solution managed by Modelon at

The goal has been to create a product that highly simplifies installation and operation. See Customer Managed Modelon Impact for further information.

Platform information🔗

Execution environment🔗

This release include following execution environments.

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

Execution environments v2024.1 v2023.2
Optimica Compiler Toolkit v1.48 v1.44
   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 v20.04 CentOS v7.4
Python environment v3.9 v3.9
C compiler GCC v9 and glibc v2.31 GCC v4 and glibc v2.17

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


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

Note, customer managed only includes the 2024.1 library bundle.

Libraries 2024.1 2023.2 2023.1
AirConditioning 1.27.0 1.26.0 1.25.0
AirConditioningAdapters 1.27.0 NA NA
AircraftDynamics 1.10.0 1.9.0 1.8.0
Electrification 1.11.0 1.10.0 1.9.0
EnergySystems 1.0.0 NA NA
EngineDynamics 2.12.0 2.11.0 2.10.0
EnvironmentalControl 3.16.0 3.15.0 3.14.0
FuelCell 1.18.0 1.17.0 1.16.0
FuelSystem 5.5.0 5.4.0 5.3.0
HeatExchanger 2.12.0 2.11.0 2.10.0
Hydraulics 4.20.0 4.19.0 4.18.0
HydroPower 2.18.0 2.17.0 2.16.0
IndustryExamples 1.4.0 1.3.0 1.2.0
JetPropulsion 2.7.0 2.6.01 2.5.01
LiquidCooling 2.12.0 2.11.0 2.10.0
Modelon 4.4.0 4.3.0 4.2.0
Pneumatics 2.16.0 2.15.0 2.14.0
ThermalPower 1.27.0 1.26.01 1.25.01
ThermoFluidPro NA NA 1.25.0
VaporCycle 2.12.0 2.11.0 2.10.0
VehicleDynamics 4.4.0 4.3.01 4.2.01

1 Custom functions provided with the 2023.1 and 2023.2 release of the Modelon libraries are not compatible with the 2024.1 platform release. Please upgrade your library dependencies if you want to continue or start using the provided custom functions.

Breaking Changes🔗

Execution environment🔗

Modelon Impact 2024.1 has migrated to Ubuntu 20.04 from CentOS7 as the underlying OS. This can affect compatibility for:

  • FMU export: The tool that the exported FMU is imported into needs to be compliant with FMUs generated from Ubuntu 20.04.
  • FMU import: The exported FMU need to be binary compliant with Ubuntu 20.04.
  • Using external C code in a custom library: The external C-code needs to be compliant with gcc v9.

Note, that with the new functionality “Access to earlier solvers for extended backward compatibility” it will be possible to continue to use the same execution environment from 2023.2 that uses CentOS7.


The 2022.2 distribution of libraries have been removed from Modelon managed. Following library versions are therefore not longer available on Modelon managed.

Library Version
AirConditioning 1.24
AircraftDynamics 1.7
Electrification 1.8
EngineDynamics 2.9
EnvironmentalControl 3.13
FuelCell 1.15
FuelSystem 5.2
HeatExchanger 2.9
Hydraulics 4.17
HydroPower 2.15
IndustryExamples 1.1
JetPropulsion 2.4
LiquidCooling 2.9
Modelon 4.1
Pneumatics 2.13
ThermalPower 1.24
ThermoFluidPro 1.24
VaporCycle 2.9
VehicleDynamics 4.1

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

Notes on updates for Modelon Impact Desktop🔗

General availability: Modelon Impact Desktop 2024-February-27

Modelon Impact Desktop is not longer being actively developed. The 2022.2 release was the last release that included new functionality of the user-interface. This version will only include updates of the OPTIMICA Compiler Toolkit and libraries.

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