Simulation of industrial energy supply systems with integrated cost optimization

Rational energy use in industry decreases costs, environmental pollution and depletion of resources. Since energy costs are often in the magnitude of the profit, a reduced energy use considerably affects the company-results. Yet, a systematic and profound analysis and optimization of the energetic processes is seldom conducted. In order to reduce the effort and increase the quality of energy system analysis, a computer aided method is being developed in a research project called TOP-Energy (Toolkit for Optimization of Industrial Energy Systems). The main goal of TOP-Energy is to support energy consultants in analyzing and optimizing industrial energy supply systems by supplying modules for documentation, simulation and evaluation of energy systems in respect to energetic, economic and environmental aspects. TOP-Energy consists of two major parts, a unifying framework and a set of modules: The former supplies the services of a modem GUT-application like module-sensitive dialogs and presentations, flow sheet editing and report generation. The latter are technical modules addressing particular aspects of energy system analysis like economical analysis or system simulation. An outstanding module of TOP-Energy is the supply system simulator called eSim, tailored to the consultant's needs. It evaluates energy supply concepts by means of historical or estimated demand data. In contrast to other simulator packages eSim supersedes costly modelling of control systems at an early stage of concept development by automatic optimization of component use. In order to model temperature sensitive components like chillers or heat pumps the conventional MILP-method was modified by employing evolutionary algorithms. The article briefly presents the basic concepts of TOP-Energy including the framework's capabilities and then puts the focus on the simulator module, discussing its foundations and the solver numeric.