Montanes R.M.,Lund University |
Windahl J.,Modelon AB |
Palsson J.,Modelon AB |
Thern M.,Lund University
Heat Transfer Engineering | Year: 2017
Concentrating solar power (CSP) technology with thermal energy storage is a renewable and emerging technology. In this work, dynamic models for analyzing and evaluating energy storage concepts and its interaction with the solar field and the power block have been developed. A physical model of a 50 MW CSP plant has been implemented in the modeling language Modelica. The models are developed in a modular, flexible structure with a well-defined interface to easily replace and test modules of various detail and complexity. Models include turbine island, steam generator, solar field, and thermal energy storage system. In addition, a decentralized control configuration has been developed. Results have been successfully validated against the reference plant key steady-state data. Dynamic response of the power block has shown expected behavior, and transient durations were comparable with settling times predicted in literature. Furthermore, the performance of the plant has been evaluated during a typical summer day including effects such as variation of solar irradiance, charging and discharging the heat storage system, and dumping excess heat in the solar field. The summer day scenario results agreed with published performance of the plant. © 2017 Taylor & Francis Group, LLC
Agency: European Commission | Branch: FP7 | Program: JTI-CP-FCH | Phase: SP1-JTI-FCH.2010.1.5 | Award Amount: 9.31M | Year: 2011
For truck applications the increasing demand for electrical power when the vehicle stands still has lead to an increasing need for an on-board electric power generator which operates with high efficiency and very low emissions. A fuel cell based auxiliary power unit (APU), with a diesel fuel processor is regarded as one of the most interesting options since it combines high efficiency, low emissions and the use of the same fuel as the main engine. The overall objectives of FCGEN wer to develop and demonstrate a proof-of-concept complete fuel cell auxiliary power unit in a real application, onboard a truck. However, the vehicle demonstration objective was changed to laboratory demonstration as the project partner, CRF, who was responsible for the vehicle demonstration work package and providing the demonstration truck has left the project after 24 months and it was not possible for the FCGEN consortium to find a suitable replacement for CRF. The APU system consisting of a low-temperature PEM fuel cell, a diesel fuel processor and necessary balance of plant components will be designed to meet automotive requirements regarding e.g. size, mechanical tolerances, durability etc. High targets are set for energy efficiency and therefore this will significantly lead to emissions reductions and greener transport solutions in line with EU targets. A key point in the project is the development of a fuel processing system that can handle logistic fuels. A fuel processor consisting of autothermal reformer, desulphurization unit, water-gas-shift reactor, reactor for the preferential oxidation of CO, will be developed. The fuel processor will be developed for and tested on standard available low sulphur diesel fuel both for the European and US fuel qualities. Another key point is the development of an efficient and reliable control system for the APU, systems, including both hardware and software modules. In the final demonstration, the fuel cell based APU will be tested in laboratory environment as the first step in a defined plan towards Vehicle demonstration.
Jonasson M.,Volvo Car Corporation |
Jonasson M.,KTH Royal Institute of Technology |
Andreasson J.,Modelon AB |
Jacobson B.,Volvo Car Corporation |
Trigell A.S.,KTH Royal Institute of Technology
Vehicle System Dynamics | Year: 2010
This paper formulates force constraints of over-actuated road vehicles. In particular, focus is put on different vehicle configurations provided with electrical drivelines. It is demonstrated that a number of vehicles possesses non-convex tyre and actuator constraints, which have an impact on the way in which the actuators are to be used. By mapping the actuator forces to a space on a global level, the potential of the vehicle motion is investigated for the vehicles studied. It is concluded that vehicles with individual drive, compared with individual brakes only, have a great potential to yaw motion even under strong lateral acceleration. © 2010 Taylor & Francis.
Liljemark S.,Vattenfall |
Arvidsson K.,Vattenfall |
McCann M.T.P.,Vattenfall |
Tummescheit H.,Modelon AB |
Velut S.,Modelon AB
Energy Procedia | Year: 2011
Dynamical simulations have been performed for CO2 transfer through a fictive but realistic transport pipeline in order to evaluate the risk of phase transition during flow transients and pipe cooling. The simulation results provide a better understanding of transport phenomena during transport of CO2 from the capture point to the storage point of a carbon capture and storage (CCS) process. Two models were developed; one to describe pressure and flow dynamics within the transport pipeline and the other to simulate transient cooling and the generation and propagation of pressure waves in the pipeline. Together these models were used to determine pressure and flow fluctuations during transient pipe cooling as well as during operation modes of load change, start-up, shut-down, and compressor trip. Pipe cooling was found to result in the slow formation of two-phase flow. Quick shut-down and load change led to the occurrence of two phase flow which was restricted to the vertical section of pipeline (injection pipe) by controlling the flow through the final control valve. Quick shut-down created pressure oscillations in the pipe with a maximum amplitude of 3 bar. During start-up mode it took 12 days to completely fill the pipeline, 6 days of which involved flow in the two-phase region. Compressor trip showed no sign of crossing the phase boundary. © 2011 Published by Elsevier Ltd. © 2011 Published by Elsevier Ltd.
Dahl J.,Volvo |
Andersson D.,Modelon AB
International Journal of Engine Research | Year: 2014
In order to comply with increasing consumer and regulatory demand for improved fuel economy and lower emissions, the engines and engine aftertreatment systems must be improved continuously. Since the complete system is very complex, models are useful in order to be able to cost efficiently develop new control strategies and selection of hardware. In this article, a model library for dynamic engine modeling in Dymola is presented. The library consists of models of the standard engine components such as manifolds, pipe, turbines, compressors, valves and mechanics. The combustion model is a mean value model and the focus has been on air path management and exhaust modeling with real-time-like simulation times, useful for engine optimization and for evaluation of control strategies. Engine simulation results from a 13-L Volvo engine demonstrates that the models capture the dynamics and have sufficient accuracy to be useful in engine optimization. © IMechE 2014.
Agency: European Commission | Branch: FP7 | Program: JTI-CS | Phase: JTI-CS-2012-2-SGO-02-048 | Award Amount: 200.00K | Year: 2013
The goal of the project is to develop the next version of the fluid property sublibrary of the Modelica Standard Library (MSL). The currently available fluids will be kept, but there is a need to extend the MSL with properties for multi-phase multi-component fluids. Most fluid properties available today are in specialized programs written in C or Fortran, like MultiFlash by InfoChem or FluidProp by TU Delft, or they are part of process engineering simulators. That makes it necessary to include external interfaces to access these properties from Modelica. CAPE-OPEN is the best known such interface with many properties available and is a natural first choice. On the other hand it is necessary to support encapsulated models as standardized in the FMI-standard, which is also maintained by the Modelica Association. Therefore, a native C/C\\/Fortran interface will also be developed in this project. The results are going to be integrated into the Modelica Standard Library.
Akesson J.,Lund University |
Akesson J.,Modelon AB |
Arzen K.-E.,Lund University |
Gafvert M.,Modelon AB |
And 2 more authors.
Computers and Chemical Engineering | Year: 2010
The Modelica language, targeted at modeling of complex physical systems, has gained increased attention during the last decade. Modelica is about to establish itself as a de facto standard in the modeling community with strong support both within academia and industry. While there are several tools, both commercial and free, supporting simulation of Modelica models few efforts have been made in the area of dynamic optimization of Modelica models. In this paper, an extension to the Modelica language, entitled Optimica, is reported. Optimica enables compact and intuitive formulations of optimization problems, static and dynamic, based on Modelica models. The paper also reports a novel Modelica-based open source project, JModelica.org, specifically targeted at dynamic optimization. JModelica.org supports the Optimica extension and offers an open platform based on established technologies, including Python, C, Java and XML. Examples are provided to demonstrate the capabilities of Optimica and JModelica.org. © 2009 Elsevier Ltd.
Gardarsdottir S.O.,Chalmers University of Technology |
Normann F.,Chalmers University of Technology |
Andersson K.,Chalmers University of Technology |
Prolss K.,Modelon AB |
And 2 more authors.
International Journal of Greenhouse Gas Control | Year: 2015
A dynamic model of the amine-based CO2-capture process is presented and applied to investigate the transient behavior of the absorption system during and after load changes in Nordjyllandsværket, a state-of-the-art coal-fired power plant with a thermal efficiency of 47.5%. Two scenarios of flexible operation in the power plant are investigated: part-load and peak load operation. Simulations of the load-variation scenarios show that implementation of active control strategies improves capture system performance with respect to capture efficiency and the heat requirement. The reboiler duty can be decreased considerably during part load operation compared to a case where no control strategy is applied. Integration of the capture process with the power plant results in an efficiency decrease of around 9 percentage points at full load and in the range of 8-12 percentage points during 60% part load operation, depending on if a process controller is used or not. Energy requirement for CO2 compression is not included in these numbers. In addition, the response time of the absorption system is significantly decreased in the cases where a process control strategy is implemented, both for part load and peak load operation. © 2014 Elsevier Ltd.
Prolss K.,Modelon AB |
Tummescheit H.,Modelon AB |
Velut S.,Modelon AB |
Akesson J.,Lund University
Energy Procedia | Year: 2011
With an increasing demand on load flexibility in power supply networks, advanced control systems for plants with carbon capture units gain in significance. Minimizing the energy demand for carbon dioxide removal under these circumstances is a major task of such a control strategy. In this work a dynamic model in Modelica of a chemical absorption process run with an aqueous monoethanolamine (MEA) is developed. Starting from a rather detailed dynamic model of the process, model reduction is performed based on physical insight. The reduced model computes distinctly faster, shows similar transient behavior and reflects trends for optimal steady-state operations reported in the literature. The model is intended to be used in the framework of JModelica.org, a platform supporting non-linear dynamic optimization. © 2011 Published by Elsevier Ltd.
Agency: European Commission | Branch: FP7 | Program: JTI-CS | Phase: JTI-CS-2009-2-ECO-02-002 | Award Amount: 80.00K | Year: 2010
With this proposal, a Modelica library for thermodynamic properties of gases and liquids that are used as working media in aircraft, and an Excel interface to the same functions with plotting capabilities for typical thermodynamic design diagrams (Temperature-Entropy and Enthalpy-Entropy) shall be developed. It is important that the complete temperature and pressure range experienced by aircraft is covered, from -60 deg Celsius to 200 deg Celsius, depending on the fluid. The pressure range depends on the fluid, as an example a range from 150 to 1100 hPa is necessary for air. Currently available model libraries dont cover the complete range. A fixed starting date of August 1st was chosen to align the project with the original planning of the ITD activities.