Introduction

Purpose

The Air Conditioning Library is intended for the steady-state and dynamic systems analysis of air conditioning and refrigeration cycles. Typical tasks are component selection, system performance optimization and verification and also control design and verification. The library can be used to analyze partial as well as complete air conditioning cycles. Models are designed in a way that is similar to the structure of real thermodynamic cycle assemblies. The library is hierarchically organized and grouped into intuitive subpackages.

Key features

• Transient and steady state simulation and parameter optimization
• Easy to use templates for standard automotive cycle configurations
• State-of-the art two-phase flow and air-conditioning models with access to source code
• Validated models for conventional and trans-critical A/C and refrigeration cycles
• Existing object-oriented, hierarchical models are open for easy modification and extension
• Model complexity level can be adjusted by simple pull-down choices: Maximum fidelity from geometric parameters or simplified parameters for fitting to component data
• Seamless integration of user-defined models into main library
• Interfaces conveniently with Simulink

Modeling and simulation

Many simulation tools are essentially user-interfaces for setting the parameters of fixed simulation models. This means that the actual equations that describe the model are impossible, or difficult, to modify by users. This Modelon modelica library offers a different approach and provides much more flexibility. In combination with a simulation tool this Modelon library is a complete modeling and simulation tool. This is important to understand, since it implies that the working procedure is slightly different and contains some additional steps:

• Build models that describe the phenomena of interest,
• Tune the model parameters,
• Use the models to set up an experiment that exposes the phenomena of interest,
• Simulate the experiment,
• Analyze the results

This Modelon library contains a large set of pre-defined models and templates that makes most modeling tasks straightforward. For many standard tasks it is possible to use the library in the same way as a pure simulation tool, i.e. it is sufficient to choose the right model, define all parameters and start the simulation.

Flexibility with prudence

It is possible for users to modify and extend most of the models in the library, and also to complement the library with custom models. It is also possible to mix with model components from other libraries. This is one of the major benefits of describing models using a high-level modeling language like Modelica. Customization of models and components can be done either from the graphical user interface and diagram view, or, for advanced users, by typing Modelica source code. There is also great flexibility in setting up experiments and analyzing results.

The flexibility implies great freedom for users to define models and experiments, but may also require more attention to details and understanding. It is completely possible to define models and experiments that contain errors. To minimize the risk of introducing errors, it is recommended to use the model and experiment templates in the library whenever possible. It is also recommended to follow the practice described in this User's Guide, even though there appear to be other ways of carrying out a specific task.