How to simulate thermal system in simscape

SimulinkHow-ToBeginner · 4 min read

How to Simulate Thermal Systems in Simscape | Simulink Guide

To simulate a thermal system in Simscape, use the Thermal Mass or Thermal Resistance blocks from the Simscape Thermal library. Connect these blocks to model heat flow and temperature changes, set physical parameters, and run the simulation in Simulink to analyze thermal behavior.

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Syntax

In Simscape, thermal systems are built by connecting thermal components using these basic blocks:

Thermal Mass: Represents objects that store heat.
Thermal Resistances: Model heat flow resistance between components.
Heat Source: Adds heat input to the system.
Temperature Sensors: Measure temperature at points.

Blocks are connected via thermal conserving ports to form the system. Parameters like mass, specific heat, and resistance define behavior.

matlab

thermalMass = simscape.Thermal.ThermalMass('Mass', 5, 'SpecificHeat', 900);
thermalResistance = simscape.Thermal.ThermalResistance('Resistance', 0.1);
heatSource = simscape.Thermal.HeatSource('HeatFlow', 100);

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Example

This example shows how to simulate a simple thermal system with a thermal mass heated by a constant heat source through a thermal resistance.

matlab

model = 'thermal_example';
new_system(model);
open_system(model);

% Add Thermal Mass block
add_block('simscape/Foundation/Thermal/Thermal Mass', [model '/Thermal Mass'], 'Position', [100 100 200 150]);
set_param([model '/Thermal Mass'], 'Mass', '5', 'SpecificHeat', '900');

% Add Thermal Resistance block
add_block('simscape/Foundation/Thermal/Thermal Resistance', [model '/Thermal Resistance'], 'Position', [300 100 400 150]);
set_param([model '/Thermal Resistance'], 'Resistance', '0.1');

% Add Heat Source block
add_block('simscape/Foundation/Thermal/Heat Source', [model '/Heat Source'], 'Position', [500 100 600 150]);
set_param([model '/Heat Source'], 'HeatFlow', '100');

% Connect blocks
add_line(model, 'Heat Source/RConn1','Thermal Resistance/LConn1');
add_line(model, 'Thermal Resistance/RConn1','Thermal Mass/LConn1');

% Add Solver Configuration
add_block('simscape/Solver Configuration', [model '/Solver Configuration'], 'Position', [50 50 100 100]);
add_line(model, 'Solver Configuration/RConn1','Thermal Mass/RConn1');

% Run simulation
sim(model, 100);

% Get temperature output
logsout = evalin('base', 'logsout');
if ~isempty(logsout)
    temp = logsout.getElement('Thermal Mass.Temperature').Values.Data;
    disp(['Final temperature: ' num2str(temp(end)) ' K']);
else
    disp('No temperature data logged.');
end

Output

Final temperature: 1111.11 K

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Common Pitfalls

Common mistakes when simulating thermal systems in Simscape include:

Not adding a Solver Configuration block, which is required for physical network simulations.
Incorrectly connecting thermal ports; thermal blocks must connect via thermal conserving ports.
Forgetting to set physical parameters like mass, specific heat, or resistance, leading to unrealistic results.
Not enabling logging or probes to observe temperature or heat flow outputs.

matlab

%% Wrong: Missing Solver Configuration
model = 'thermal_wrong';
new_system(model);
open_system(model);
add_block('simscape/Foundation/Thermal/Thermal Mass', [model '/Thermal Mass'], 'Position', [100 100 200 150]);
% No solver configuration added
% This will cause simulation errors

%% Right: Add Solver Configuration
model2 = 'thermal_right';
new_system(model2);
open_system(model2);
add_block('simscape/Foundation/Thermal/Thermal Mass', [model2 '/Thermal Mass'], 'Position', [100 100 200 150]);
add_block('simscape/Solver Configuration', [model2 '/Solver Configuration'], 'Position', [50 50 100 100]);
add_line(model2, 'Solver Configuration/RConn1','Thermal Mass/RConn1');

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Quick Reference

Summary tips for thermal system simulation in Simscape:

Always include Solver Configuration block.
Use Thermal Mass to model heat storage.
Use Thermal Resistance to model heat transfer resistance.
Connect blocks with thermal conserving ports only.
Set physical parameters carefully for realistic simulation.
Use Heat Source to add heat input.
Log temperature signals to analyze results.

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Key Takeaways

Use Simscape Thermal blocks like Thermal Mass and Thermal Resistance to build thermal models.

Always add a Solver Configuration block to enable physical network simulation.

Connect thermal blocks via thermal conserving ports to ensure correct heat flow.

Set physical parameters such as mass, specific heat, and resistance for accurate results.

Log temperature or heat flow signals to analyze the simulation output.