Agent based modeling of energy networks

Attempts to model any present or future power grid face a huge challenge because a power grid is a complex system, with feedback and multi-agent behaviors, integrated by generation, distribution, storage and consumption systems, using various control and automation computing systems to manage electricity flows. Our approach to modeling is to build upon an established model of the low voltage electricity network which is tested and proven, by extending it to a generalized energy model. But, in order to address the crucial issues of energy efficiency, additional processes like energy conversion and storage, and further energy carriers, such as gas, heat, etc., besides the traditional electrical one, must be considered. Therefore a more powerful model, provided with enhanced nodes or conversion points, able to deal with multidimensional flows, is being required. This article addresses the issue of modeling a local multi-carrier energy network. This problem can be considered as an extension of modeling a low voltage distribution network located at some urban or rural geographic area. But instead of using an external power flow analysis package to do the power flow calculations, as used in electric networks, in this work we integrate a multiagent algorithm to perform the task, in a concurrent way to the other simulation tasks, and not only for the electric fluid but also for a number of additional energy carriers. As the model is mainly focused in system operation, generation and load models are not developed

Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems

This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The study introduces the motivation, presents the simplified modeling methodology, and illustrates the model and simulating structure. A preliminary evaluation of the method is conducted with two simple simulations. The proposed “node-branch-state” modeling approach could be easily modified, expanded and integrated into a detailed thermal model. The paper concludes with some discussions on future work

HVAC integrated control for energy saving and comfort enhancement

The overall attainable reduction in energy consumption and enhancement of human comfort of Heating, Ventilating, and Air Conditioning (HVAC) systems are dependant on thermodynamic behavior of buildings as well as performance of HVAC components and device control strategies. In this paper by refining the models of HVAC components, the influence of integrated control of shading blinds and natural ventilation on HVAC system performance is discussed in terms of energy savings and human comfort. An actual central cooling plant of a commercial building in the hot and dry climate condition is used for experimental data collection, modeling and strategy testing. Subject to comfort constraints, interactions between the building's transient hourly load and system performance are considered to show how the system energy consumption varies at different control strategies. For validation, a holistic approach is proposed to integrate dynamic operations of shading devices with direct and indirect ventilation of a commercial building equipped with a central cooling plant. Simulation results are provided to show possibility of significant energy saving and comfort enhancement by implementing proper control strategies

The importance of communication in concept design simulation

The European Union has taken a strong leadership role in promoting energy efficiency in buildings. This is among other things highlighted by the Directive on the Energy Performance of Buildings, which is designed to promote the improvement of energy performance of buildings in member states. One of the benefits of this directive is that it provides an integrated approach to different aspects of buildings energy use, which until now only a few member states were doing, and that all aspects are expressed in simple energy performance indicators. In order to achieve such reductions of the energy use in new buildings it will require development of new construction solutions, new types of building envelopes, and development of new building materials. It will also require the development of more holistic building concepts, sustainable buildings where an integrated design approach is needed to ensure a system optimization and to enable the designer(s) to control the many design parameters that must be considered and integrated. It is therefore important to understand how this design process works and how the architect can be enabled to integrate sustainable design solutions. Computer-based modeling and simulation is becoming more and more significant for the prediction of future energy and environmental performance of buildings and the systems that service them. Modeling and simulation can and should play a vital role in building and systems design, commissioning, management and operation. Although most practitioners will be aware of the emerging building simulation technologies, yet few are able to claim expertise in its application. In the design of sustainable buildings it is therefore necessary to identify the most important design parameters in order to develop more efficiently alternative design proposals and/or reach optimized design solutions. This can be achieved by applying sensitivity analysis early in the design process. Previously, environmental simulation of building performance was only done by engineers at the end of the design process. Any weak points in the performance of the design could then be ‘fixed' by adding heating, cooling, shades, vents, fans, panels, etc ... However, at the end of the design process it is too late. The decisions made early on in the design process have the largest impact. In addition, environmental issues are becoming more important, the complexity of the building design is increasing, and simulation tools are becoming more architects friendly. Therefore, in the design of sustainable buildings it will be very beneficial to be able identify the most important design parameters in order to develop more efficiently alternative design proposals and/or reach optimized design solutions. Communication between architects and engineers paper will become more common but also more important. Digital architecture has to take these challenges into account and develop a common language for architects that enable integrated design in order to tackle the problems stated above

The Application Of Bond Graphs To Electrical Machinery And Power Engineering

The bond graph technique, which has been related almost entirely to the field of mechanics, is a modeling procedure where emphasis is placed on the flow of power and energy in a system. Through specific digital simulation programs such as ENPORT IV and V and THTSIM the state space representation, associated output equations and system dynamic response are directly obtainable from the bond graphs. This approach has a great advantage where a complex system is composed of electrical, mechanical, thermal, hydraulic or pneumatic subsystems, such as would exist, for example; in a boiler, turbine, generator exciter system together with its associated controls. The purpose of this paper is three-fold: (1) to develop interest in the bond graph modeling technique in power engineering (2) to develop bond graph models for typical synchronous and induction machines which are not as well developed in the literature as are the graphs of mechanical components and (3) to complete some of the missing links in the development of bond graphs for electromechanical machines. Standard well known orthogonal axis transformations are used in the model development. The bond graphs thus developed from accurate mathematical relations can be easily integrated into other electrical or non-electrical systems through the power bonds of the graphs. Copyright © 1983 by The Institute of Electrical and Electronics Engineers, Inc