Bernhard Heinzl

Interdisciplinary Strategies for Simulation-Based Optimization of Energy Efficiency in Production Facilities

This paper presents an approach for interdisciplinary optimization of energy efficiency in production plants. Domain-specific areas of action are discussed as well as the integration into a dynamic co-simulation that helps predicting the impact and financial benefit of selected energy saving measures by comparing and quantifying different scenarios. This should help giving incentives and creating impulses for strategic investment decisions. In a comprehensive methodological approach, optimization potential of both the production process itself as well as the production infrastructure is combined. The technical implementation involves several simulation environments and a framework for synchronization and data exchange in terms of co-simulation. The paper concludes with a discussion of some exemplary simulation results.

Investigating communication and step-size behaviour for co-simulation of hybrid physical systems

Abstract This paper discusses the method of cooperative simulation of discrete and continuous models with the Building Controls Virtual Test Bed, a software environment that allows coupling different simulation programs. In the course of a project aiming the energy optimization in cutting factories, models of machines of differing complexity and a building containing them have to be implemented to further simulate the thermal processes. Since all partial models require individual modelling approaches, solver time steps, solvers or even simulators, the method of co-simulation is considered. The partial models will be implemented with Modelica, MATLAB, Simulink and Simscape and accessed with the co-simulation tool BCVTB. The simulation results show that this method of co-simulation can be sufficient for the needs of describing thermal systems with large time constants but has to be found insufficient for simulations requiring high accuracy and variable step solvers in the overall simulation.

Object-oriented Modelling of Machine Tools for Energy Efficiency Analysis in Production

Abstract There are a number of research projects with the aim of increasing energy efficiency in production. One of them, the research project INFO, attempts to make qualified predictions about the effectiveness of different energy saving approaches by using a comprehensive simulation model of production halls including all micro- and macro-structures. In order to gain knowledge about the optimization potential in the micro-structures of production plants, simulation models of typical machine tools are developed for energy analysis. Using object-oriented modelling for physical systems allows combining component models of mechanical, electrical and thermal parts in one multi-domain model. This bottom-up approach is combined with stepwise top-down modelling in several stages in order to identify numerical boundaries and the level of modelling detail necessary for investigating certain physical aspects.

BCP - A Benchmark for Teaching Structural Dynamical Systems

Abstract New object-oriented modelling techniques for physical systems along with more complex systems of interest lead to increasing requirements on modern simulators regarding performance and stability as well as state event modelling and event handling in combination with hybrid and structural dynamic systems. To see how modelling and simulation environments deal with such systems and to compare new approaches to hybrid modelling, a new benchmark is defined using three case studies with modelling and simulation tasks. The first case study investigates the classic bouncing ball example with some extensions. The second example discusses an electrical circuit - it can be used to compare the simulation results of different implementation techniques (e.g. physical modelling vs. classical DAE form) in one simulator. The third case study is a definition of a pendulum on a rope with free falling phase, representing another simple structural dynamic mechanical system. These three parts offer a spectrum of questions for testing basic features for handling hybrid and structural dynamic physical systems and they represent minimum requirements on hybrid simulators regarding state events.

Using coupled simulation for planning of energy efficient production facilities

To meet the increasing requirements of sustainable production and to assure economic competitiveness, novel strategic approaches are necessary in designing production systems and to increase energy efficiency in the manufacturing industry. Individual areas within production facilities (e.g. production system, energy system, building hull) can be analyzed individually by using simulation-based methods. In order to access additional optimization potential, it is necessary to expand the boundaries of such simulations and to consider dynamic interactions between individual optimization fields. This work presents an approach for an interdisciplinary co-simulation, in which, for an overall integrated simulation, several simulation environments are coupled that periodically exchange data quasi-parallel at runtime. This allows not only to combine different model descriptions, but also multiple calculation algorithms, each specifically tailored to the individual needs of the respective field of engineering. A case study of a metal-cutting production facility presents an application example. The goal is to provide a decision-support tool for the early planning stages of production facilities that allows making qualified predictions about the effect and financial impact of different energy saving measures.

From BIM Models to Integrated Energy Efficiency Applications for Industrial Facilities

Raised interest in efficient use of available resources in industrial facilities prompts for software-tools to predict and manage energy demand of the whole system. An integrated approach considering all energy consumption contributors, classified into building, energy system, production and logistics, is developed within the research project Balanced Manufacturing (BaMa). Thereby BIM models of industrial spaces containing valuable information are used for creating a comprehensive representation of building-related aspects in a hybrid simulation environment, able to assess manufacturing and auxiliary energy demands.For testing the applicability of this integrated hybrid approach, a prototype is developed based on an actual use case. The simplification procedure is presented and the energy performance results are compared with that of an established building energy modelling software, discussing advantages and limitations. Essential information that needs to be transferred from the BIM model is clarified and prioritised.

Discussion of two Case Studies on DAEs using Different Approaches for Regularisation

The object-oriented model description of physical or mechanical systems leads to differentialalgebraic equations. In general the numerical solution of such equation systems is very complex, numerically extensive or may even be impossible. Therefore it is important to find methods for solving given equation system, this leads to the so-called index reduction and regularization methods. This paper gives a short overview of common methods of index reduction. Additionally a classification of these different approaches is made. Afterwards each approach is presented in detail and the advantages and disadvantages of the different methods are discussed. In order to compare the different index reduction methods, the methods described above are demonstrated by various examples. For the comparability of the different methods the obtained numerical solutions and the deviation from the constraint equations are displayed graphically. Therefore the distinct approaches can be compared with regard to their numerical solutions. The two examples are mechanical systems with differential index three. The equations of motion of a pendulum on a circular path in Cartesian coordinates and the motion of the double pendulum in Cartesian coordinates, which shows a chaotic behaviour, are used as case studies. Introduction • • • 1 Basic Definitions C Poell et al. Case Studies on Different DAE Regularization Methods 180 SNE 24(3-4) – 12/2014 TN 2 Regularisation Methods 2.1 Differentiation and substitution of the constraint 2.2 Baumgarte-Method 2.3 Pantelides Algorithm • • • • • • C Poell et al. Case Studies on Different DAE Regularization Methods SNE 24(3-4) – 12/2014 181 T N 2.4 Orthogonal Projection method • •

Implementation of Quantized State Systems in MATLAB/Simulink

Common practice in the simulation of continuous systems is to discretize the time in order to obtain a numerical solution. The Quantized State System (QSS) approach makes it possible that the discretisation is applied to the state variables, instead of the time range. In other words continuous systems can be simulated event-based with the QSS method. It also effects a new orientation and leads among other things to very efficient state event detection. Ernesto Kofman and Sergio Junco presented the QSS method in the DEVS formalism [1]. This paper describes how the implementation of the QSS method in Simulink/SimEvents works and which restrictions still exist.