MBL Version 6.0

Modelon Library 6.0 is part of Modelon's 2025.2 release.

New Features

Modelon.Thermofluid

Updates for significant speed-up of certain fluid network models

  • Two types of changes have been implemented in all Modelon.Thermofluid components, and Modelon libraries based on these, that can give significant speed up of certain models 
    • Propagation of fluid temperature through fluid connector. This is enabled by setting the new Advanced tab parameter "temperatureFromUpstream" to true.
    • Thorough reduction of equations under positive flow rate assumption.
  • Model types that benefit the most from using the new model simplifications are
    • Large fluid network models with a large number of relatively simple components. For example coolant networks
    • Fluid network models with large range media models (for example gas property models based on NASA Glenn correlations), using relatively simple component models
    • Note on refrigerant networks: Although fluid property models are usually detailed, component models are also usually detailed and therefore the simplifications in question are not expected to give significant performance improvements.
  • For more details on motivation and usage, see the information section Model simplifications
  • Note, breaking changes:
    • Users need to be aware of two cases that will require manual changes to their models, after upgrading to MBL 6.0:
      • Equation-based component models that introduce a fluid connector and assign the internal variables by equations - for example fluid compoennt models written from scratch by users, or component models that have been duplicated from the Modelon Base Library:
        • One extra equation need to be included per fluid connector instance to get the model to work with this update.
      • Components that have the positiveFlow parameter set to true, but in fact fluid is flowing from outlet to inlet, or portB to portA
        • If this occur, warnings will be printed in the simulation log. With this update, the above scenario may result not only in poor performance predictions, but in violated mass and energy balances. The parameter positiveFlow must be set to false if fluid flows from the outlet port to the inlet port.
    • Please see further information in on the page Converting to MBL 6.0 for details how to identify and resolve conversion issues due to these updates.


  • New moist air-type sensors for relative humidity and dew temperature calculation
  • StratifiedTank and StratifiedTankInternalHX models have been added to the library. These models support the simulation of thermal energy storage systems by capturing stratification effects and internal heat exchange. The internal HX variant enables modeling of secondary fluid circuits for integrated heating or cooling. Example models are included to demonstrate typical use cases and validate thermal layering, flow dynamics, and energy transfer behavior.
  • New heat transfer correlation added ChevronMartinSinglePhase, the correlation was added to replicate the behaviour of deprected heat exchanger models in the new heat exchnager models in AirConditioningLibrary.
  • The start value parameter dialogs for heat exchangers have been updated:
    • The tab name is Starting point instead of Initialization
    • initOpt has been renamed to howToStart
    • The init records have been renamed to startingPoint
    • For two-phase fluids, new options for providing the starting point has been added:
      • Pressure and temperature or vapor quality. Give a pressure value and select if the fluid is saturated or not. If it is saturated, vapor quality can be given to define the point in the two-phase region. If it is not saturated, temperature is given.
      • Pressure and superheat. Give a pressure value and a superheat (temperature difference above the dew point) to specify a starting point in the vapor region.
      • Pressure and subcooling. Give a pressure value and a subcooling (temperature difference below the boiling point) to specify a starting point in the vapor region.
      • Dew line temperature and superheat. Give the dew line temperature and a superheat value to specify a starting point in the vapor region.
      • Bubble line temperature and subcooling. Give the bubble line temperature and a subcooling value to specify a starting point in the liquid region.

Improvements

Modelon.Media

  • Improved inlining for some functions in two-phase media

Modelon.Thermofluid

  • Pumps that use a table to define torque were using linear interpolation previously. Interpolation is now changed to smooth interpolation to support analytic Jacobians.
  • Added asserts that will produce either simulation warnings or errors in case of positive flow rate assumption being used and actual flow rate is negative. The threshold flow rate can be set as a parameter in the "Settings_TF" component. The threshold "m_flow_min_positive "  is by default -1e-5 kg/s, and the assert type can be changed from warning (default setting) to error with the parameter "m_flow_min_severity".

Bug fixes

Modelon.Thermofluid

  • Fixed a bug in the two-phase fluid channel model - Modelon.ThermoFluid.FlowChannels.DistributedTwoPhase - when used with the Advanced option frictionDistribution = Friction-Friction. This option configures the channel to expose flow models on both ports, as desired when connection to volumes on both sides. This option previously used the downstream component fluid properties for pressure loss calculation beween the last control volume and the outlet port. This meant that the positiveFlow parameter could affect the resulting pressure loss also for the positive flow case. This has been fixed by shifting so that the upstream fluid properties are used for all segment pressure loss calculations and upstream component properties are used for the loss between inlet port and the first control volume. With the fix, for positive flow rate (flow from inlet to outlet), the positiveFlow parameter has not influence on results. Compared to the previous version, flow resistance is affected by the shift of used properties. In a channel where fluid phase change occur pressure loss will be computed with more emphasis on upstream properties, so for the condensation case pressure loss is expected to increase, and for evaporation pressure loss in expected to decrease. For channels without ongoing phase change, the result difference is expected to be very small. Higher discretization number will also reduce the effect of this change. 

Conversion of User Libraries

User libraries will automatically be converted to version 6.0. These conversions are made using the included conversion script: Modelon/Resources/Scripts/Convert_to_6.0.mos.

Note: The fluid connector has one additional variable and for existing models using the connector and being defined by equation, an equation has to be added manually. For instructions, see this page.

As of this release, 32-bit binaries are removed and support is dropped.

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