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Lemonergy · Studio block

Phase-change thermal mass

Enthalpy storage with a finite linear melting interval; constant sensible heat capacity, no supercooling or hysteresis

Implementation ID
phase-change-mass
Reviewed
2026-10-27

Behavior

Conserving component solved simultaneously with the connected network. Enthalpy storage with a finite linear melting interval; constant sensible heat capacity, no supercooling or hysteresis

Interface

Phase-change thermal mass interfaceInputs or arguments on the left, observed outputs on the right. Conserving terminals appear below the component. The tables give units and behavior.Phase-change thermal massStudio blocktemperatureliquidFractionstoredEnergyh
Original Lemonergy interface view. Lines identify ports; they are not a completed simulation circuit.
Ports and observed outputs
NameDirectionUnitMeaning
hterminalK; Wthermal conserving connection; absolute temperature with balanced heat flow.
temperatureoutputKRecorded temperature measurement from the conserving simulation.
liquidFractionoutputfractionRecorded liquid fraction measurement from the conserving simulation.
storedEnergyoutputJRecorded stored energy measurement from the conserving simulation.

Parameters

Defaults are initial model values. Select values for your own model and operating conditions.

Configuration fields
ParameterUnitDefaultMeaning and limits
Mass
massKg		kg1Material mass that contributes sensible and, where enabled, latent heat storage.
Minimum 1e-09; Maximum 1000000000
Specific heat capacity
specificHeatJkgK		J/(kg K)2000Sensible heat required per unit mass and kelvin.
Minimum 1e-06; Maximum 1000000000
Latent heat
latentHeatJkg		J/kg200000Energy per unit mass stored while the liquid fraction changes from zero to one.
Minimum 0; Maximum 1000000000
Solidus temperature
solidusK		K330Temperature at which melting begins in the finite transition interval.
Minimum 0; Maximum 5000
Liquidus temperature
liquidusK		K334Temperature at which the model is fully liquid.
Minimum 0; Maximum 5000
Initial temperature
initialTemperatureK		K300Absolute initial temperature of the thermal storage.
Minimum 0; Maximum 5000

Equations and rules

  • H = m cp T + m latentHeat × liquidFraction
  • liquidFraction = clip((T − solidus)/(liquidus − solidus), 0, 1)
  • dH/dt = Σ Q̇in

Worked example

Phase-change thermal mass worked example

Editable first-party network. mass: specificHeatJkgK=2; mass: latentHeatJkg=100; mass: solidusK=310; mass: liquidusK=320; mass: initialTemperatureK=310; heater: heatFlowW=12. Checks below were verified in the native execution engine.

Open Studio example after release →
Numerical checks for the bundled synthetic example
OutputTime (s)Expected valueUnitAbsolute tolerance
temperature
mass/temperature		1311K0.00031100000000000273
liquidFraction
mass/liquidFraction		10.1fraction1.0000000000020123e-07
storedEnergy
mass/storedEnergy		112J1.2000000000020007e-05

Use in a workflow

Phase-change thermal mass worked example

Enthalpy storage with a finite linear melting interval; constant sensible heat capacity, no supercooling or hysteresis

  1. Phase-change thermal mass: Conserving component solved simultaneously with the connected network. Enthalpy storage with a finite linear melting interval; constant sensible heat capacity, no supercooling or hysteresis
    • Use the block reference for settings and connections.
    • Implementation tested locally; public release pending.
Open Studio example after release

Connected concepts

Limits and interpretation

  • Enthalpy storage with a finite linear melting interval; constant sensible heat capacity, no supercooling or hysteresis
  • Demonstration parameters are not calibrated hardware data. Singular or incompatible ideal constraints and unsupported state ranges stop the run.

Scientific and mathematical references

These sources explain the scientific and mathematical background. The behavior, interface and limits above define the Lemonergy implementation; a citation does not imply every model option in the source is implemented.

  1. University Physics Volume 2, §1.6: Mechanisms of Heat Transfer

    OpenStax, Rice University

    Technical reference · Conduction, convection, radiation and thermal resistance.

  2. Phase Changes

    OpenStax, Rice University

    Technical reference · Underlying physical law or reduced-model basis; Lemonergy implementation choices and limits are documented separately.

Implementation sources

This reference follows the public interface and locally verified numerical checks for an upcoming release.

Contract: Lemonergy Studio public contract · Verification record: verification-2026-10-27

  • docs/glossary/native-block-verification.json

This implementation and its workflow uses (JSON) · Knowledge graph (JSON-LD)