Proposal of New Object-Oriented Equation-Based Model Libraries for Thermodynamic Systems
Christoph F. Richter · Digitale Bibliothek Braunschweig (Verbundzentrale Göttingen (VZG)) · 2008
This thesis proposes two new model libraries for fluid properties and for components that can be used for the simulation of thermodynamic systems such as refrigeration, air-conditioning, and heat-pump systems. The new fluid property library is written in C/C++ and can be interfaced from various software tools and programming languages. The new component model library is written in the object-oriented equation-based modeling language Modelica. Furthermore, tools for the automated generation of class diagrams and the visualization of the solution process as well as the numerical results in relevant diagrams are presented. Both new libraries are based on a thorough object-oriented analysis. A set of general design rules for the development of object-oriented component model libraries is formulated to ensure that the resulting library can be used by the entire spectrum of possible users from experienced developers to design engineers. The new object-based fluid property library is based on a generalized approach to include external fluid property computation codes in Modelica. It is simple to extend to additional external fluid property computation codes. It allows for a numerically efficient handling of fluid properties in Modelica and in a number of software tools. The new model library for components and systems was developed based on the newly introduced design rules. It features a structure that is simple to understand and flexible to allow for extensions. All balance equations are formulated in an easy and comprehensible way in base components. The new component model library contains models with different levels of detail to allow for a problem-dependent model selection. Two applications are presented to demonstrate the capabilities of the two new libraries and to demonstrate their extendibility and multidisciplinarity.