Environmental Control Library

Modelon’s Environmental Control Library is a Modelica library for aircraft environmental control systems analysis and design. The library is designed to study energy consumption and thermal conditions that affect the level of comfort for passengers and crew.

These performance aspects are driven by large variations in ambient conditions such as humidity and temperature. The models provided by Environmental Control Library account for these effects through first principles and fully support bidirectional flow.

The library has been developed internally at Modelon for a number of years together with a European airframer, and starting with version 3.1 it is publicly available. Modelon is now able to offer out of the box a library reinforced through industrial collaboration deployment.

The library provides an efficient and numerically robust framework suitable for large-scale complex systems. Component models include heat exchangers, compressors, turbines, ejectors or jet pumps, water separator, valves, cabin and pipes.


  • Flexible composition of user-defined system architectures for efficient model management 
  • Real-time capable high performance models enabling Hardware-In-the-Loop (HIL) applications
  • Full support for bidirectional flow for analysis of all modes of operation on ground and in flight
  • Efficient property models of moist air enabling robust and fast simulation of large-scale systems
  • Online visualization of simulation results for intuitive understanding of the system behavior 
  • Configurable model fidelity for faster simulation and right complexity level.

Air conditioning performance assessment.
The bleed air from the engine is directed to the primary heat exchanger where it is cooled with ambient ram air. The air is then compressed and cooled down further in the main or secondary heat exchanger. A high pressure water separation loop allows for the extraction of free moisture.

The Environmental Control Library is being used successfully by industry in system performance assessment and control system design.

The models are used to verify how the resulting system robustly delivers air conditioning and auxiliary cooling to all aircraft thermal loads.

Applications include:

  • Design and assessment of bleed and bleedless architectures
  • Control system verification
  • Full vehicle thermal management
  • Verification of critical components – is sufficient moisture extracted in the high pressure water separation loop. 

Video Keynote

Using the Modelica open-standard in product development at United Technologies Corporation. 52 minutes video keynote of Dr. Clas Jacobson, Chief Scientist at United Technologies. Record from Modelica Conference 2014.

Environmental Control Library is a product of Modelon and is distributed by Modelon and partners worldwide.

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Product Sheet 

For environmental control systems and fuel systems, SAAB has together with Modelon developed libraries [that are] commercially available.

Ingela Lind and Henric Andersson , SAAB Aeronautics