18 results on '"Noureldin, Kareem"'
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2. Gradient controlled startup procedure of a molten-salt power-to-heat energy storage plant based on dynamic process simulation.
- Author
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Schulte, Jonas, Schwager, Christian, Noureldin, Kareem, May, Martin, Teixeira Boura, Cristiano J., and Herrmann, Ulf
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FUSED salts ,DYNAMIC simulation ,ENERGY storage ,POWER plants ,SOLAR power plants ,CARBON emissions ,NEW business enterprises ,CAPITAL investments - Abstract
The integration of high temperature thermal energy storages into existing conventional power plants can help to reduce the CO2 emissions of those plants and lead to lower capital expenditures for building energy storage systems, due to the use of synergy effects [1]. One possibility to implement that, is a molten salt storage system with a powerful power-to-heat unit. This paper presents two possible control concepts for the startup of the charging system of such a facility. The procedures are implemented in a detailed dynamic process model. The performance and safety regarding the film temperatures at heat transmitting surfaces are investigated in the process simulations. To improve the accuracy in predicting the film temperatures, CFD simulations of the electrical heater are carried out and the results are merged with the dynamic model. The results show that both investigated control concepts are safe regarding the temperature limits. The gradient controlled startup performed better than the temperature-controlled startup. Nevertheless, there are several uncertainties that need to be investigated further. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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3. StoreToPower - Phase 1: Stromspeicherung in Hochtemperatur-Wärmespeicherkraftwerken
- Author
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Arnold, Witold, Giuliano, Stefano, Koll, Gerrit, May, Martin, Bauer, Thomas, Belik, Sergej, Bohnes, Sebastian, Dersch, Jürgen, Dreißigacker, Volker, Geyer, Michael P., Handschuh, Nils, Herrmann, Ulf, Klassing, Freerk, Krüger, Michael, Noureldin, Kareem, Roldan Serrano, Maria Isabel, Stollenwerk, Dominik, Schulte, Jonas, Trieb, Franz, and Zunft, Stefan
- Subjects
Stromspeicherung in Hochtemperatur-Wärmespeicherkraftwerken - Published
- 2022
4. Annual performance assessment of a 50 MWe commercial solar tower plant with improved open volumetric receiver.
- Author
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Schwarzbözl, Peter, Giuliano, Stefano, Noureldin, Kareem, Doerbeck, Till, Rosselló, Aina, and Schrüfer, Johannes
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HEAT storage ,THERMAL efficiency ,TEST systems - Abstract
Central receiver systems with open volumetric air receiver and packed bed thermal storage are an alternative to the currently deployed salt and steam receiver plants. The air receiver technology is being tested as a complete system at the 1 MW
e test and demonstration plant Solar Tower Jülich since 2009 and shows high robustness and availability. Recent developments focused on increasing the thermal receiver efficiency. Changing the receiver geometry to a cavity type and further structural improvements resulted in an efficiency increase to above 85%, as experiments and CFD simulation models show. The high dynamic flexibility could be further enhanced. A commercial reference plant with 50 MWe power level was defined for a potential location in South Africa. An LCOE analysis based on an annual performance simulation was conducted for several design and operational alternatives. Under good conditions, results show LCOE values below 90 €/MWh for the single 50 MWe standard unit. Higher power levels can be reached by multiplying such standard units, leading to further cost savings. [ABSTRACT FROM AUTHOR]- Published
- 2022
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- View/download PDF
5. Encyclopedia of Sustainability Science and Technology: Dynamical Behavior of CSP Plants
- Author
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Hirsch, Tobias, Dersch, Jürgen, Noureldin, Kareem, Nouri, Bijan, Maldonado Quinto, Daniel, Schwarzbözl, Peter, Uhlig, Ralf, and Wilbert, Stefan
- Subjects
parabolic trough ,solar tower ,CSP ,solar power plant ,Dynamic behaviour - Published
- 2021
6. Evaluating the Potential Benefit of Using Nowcasting Systems to Improve the Yield of Parabolic Trough Power Plants with Single-Phase HTF
- Author
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Noureldin, Kareem, Hirsch, Tobias, Nouri, Bijan, Yasser, Zeyad, and Pitz-Paal, Robert
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field control ,lcsh:T ,Solare Hochtemperatur-Technologien ,nowcasting ,transient simulation ,lcsh:Technology ,DNI maps - Abstract
Solar field developers include innovative solutions to optimize the energy production of their plants. Simulation tools play a significant role in the design and testing phases as they provide estimations of this yield in different conditions. Transient processes, like passing clouds and solar field start-up, are specifically challenging to optimize and estimate using such simulation tools. Solar fields are subject to high degree of both temporal and spatial variability in the energy input and a detailed estimation can be achieved by simulating subsystems within acceptable time and computational power. Hence, such simulation tools cannot be utilized for tests under realistic operation conditions. The Virtual Solar Field is a computationally efficient simulation tool that allows a detailed transient simulation of parabolic trough solar fields based on single-phase fluids. Using this tool, developers could reproduce a transient test case with exactly the same disturbances to provide fair comparisons between different configurations. In this paper, an evaluation process based on numerical simulations using the Virtual Solar Field is presented. The economic benefit of novel innovative control concepts can be assessed according to the presented scheme. This is demonstrated by evaluating the potential benefit of availability of spatial DNI nowcasts on the control of parabolic trough solar fields. Results show that nowcasting can increase the economic revenue of commercial power plants by up to 2.5% per day. This proves the feasibility of installing such systems.
- Published
- 2021
- Full Text
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7. Vorhersagemethoden für Solarstrahlung basierend auf Wolkenkameras
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Kraas, Birk, Schmidt, Thomas, Forstinger, Anne, Wilbert, Stefan, Nouri, Bijan, Noureldin, Kareem, and Hirsch, Tobias
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Wolkenkamera ,Qualifizierung ,WobaS-A ,Nowcasting ,WobaS - Published
- 2020
8. A way to increase parabolic trough plant yield by roughly 2% using all sky imager derived DNI maps.
- Author
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Nouri, Bijan, Noureldin, Kareem, Schlichting, Tim, Wilbert, Stefan, Hirsch, Tobias, Schroedter-Homscheidt, Marion, Kuhn, Pascal, Kazantzidis, Andreas, Zarzalejo, Luis F., Blanc, Philippe, Yasser, Zeyad, Fernández, Jesús, Pitz-Paal, Robert, and Richter, Christoph
- Subjects
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PARABOLIC troughs , *PLANT yields , *SOLAR power plants , *MAXIMUM power point trackers , *SKY , *POINT set theory - Abstract
Solar fields of parabolic troughs are extensive complex thermal hydraulic facilities. Intra-hour and intra-minute variabilities of the DNI, mainly caused by passing clouds, pose an operational challenge for parabolic trough power plants. Under perfect circumstances a solar field controller would adjusts the mass flow in such a way, that the design temperature is always maintained constant with a maximized focus rate. However, heterogeneous irradiance conditions or flow distribution may cause some solar field sections to temporarily overheat while others may not reach the set point temperature, which in turn leads to an economic loss. State of the art solar field controllers have only access to incomplete information on spatial DNI variability, from DNI measurements of few pyrheliometers. Solar field controllers could be optimized with access to highly resolved DNI informations both in space and time. Such DNI information can be provided by all sky imager (ASI) based irradiance monitoring systems. In a previous study we developed and benchmarked new solar field controllers with access to spatial DNI information from an ASI system for a 50 MWe plant close to Córdoba (Spain). Significant improvements in revenue were observed. Yet, this previous study was limited to 22 days only. In this study, we estimate the potential benefit of these new solar field controllers over a 2 year period on the basis of the simulation results over 22 days. The upscaling method makes use of DNI variability classes. Using the ASI data we obtain a significant improvement in revenue up to 2% for the 2 year period. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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9. Virtual Solar Field model VSF - A universal tool to improve solar field operation and optimize its yield
- Author
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Noureldin, Kareem, Hirsch, Tobias, and Pitz-Paal, Robert
- Subjects
parabolic trough ,Virtual Solar field ,solar field control - Published
- 2018
10. The Benefit of DNI maps to improve Parabolic Trough Solar Field Control during Trasnient Processes
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Noureldin, Kareem, Hirsch, Tobias, Kuhn, Pascal Moritz, Nouri, Bijan, and Wilbert, Stefan
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parabolic trough ,Nowcasting ,control - Published
- 2018
11. Modelling and control of transients in parabolic trough power plants with single-phase heat transfer fluids
- Author
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Noureldin, Kareem, Pitz-Paal, Robert, and Mitsos, Alexander
- Subjects
parabolic trough ,CSP ,Virtual Solar Field ,Operation assessment ,solar field control ,concentrating solar power (CSP) ,performance assessment ,ddc:620 ,transient simulation ,Parabolic Troughs ,Simulation tool ,solar field modelling - Abstract
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2018; Aachen 1 Online-Ressource (xxiii, 155 Seiten) : Illustrationen, Diagramme (2019). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2018, Optimizing solar field operation and control during transient processes, like passing clouds and solar field start-up, is key to improve the competitiveness of line-focus solar thermal power plants in comparison to other renewable energy technologies. Although Simulation tools play a significant role in the design and optimization procedures, common solar field computational models cannot predict the behaviour of such a system exposed to high degrees of, both, temporal and spatial variability in the energy input. Some very detailed tools can only simulate parts of the system within acceptable time and computational power, and hence, they are not utilized as platforms to test new concepts under realistic operation conditions. On the other hand, tests in pilot or full-sized solar fields not only are too costly to prove a concept, but it is also nearly impossible to reproduce a transient test case with exactly the same disturbances to provide fair comparisons. Thus, a novel transient solar field model, the Virtual Solar Field (VSF), is developed within the scope of this thesis. The model couples a static hydraulic flow model with a detailed dynamic loop model making use of the different time scales in the system. This results in an accurate and computationally efficient simulation tool for commercial power plants scale, such that, for example, 10 hours of Andasol-III solar field operation can be simulated in under 10 minutes. VSF has been validated against solar field operation data from Andasol-III as presented in the thesis. Also new control schemes that use direct normal irradiance (DNI) maps from nowcasting systems, as well as single loop valve control have been implemented and tested in VSF. A controller performance assessment scheme based on energy output and conversion efficiency has been developed to estimate the expected revenues of the solar field within the simulated time. This provides information to quantify the benefits of using one control strategy over another. The availability of the simulation tool also paves the way for developing model-predictive control strategies to optimize the field operation and production., Published by Aachen
- Published
- 2018
- Full Text
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12. VSF – An Opportunity to Optimize Transient Processes in Line-Focus CSP Power Plants
- Author
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Noureldin, Kareem, Hirsch, Tobias, and Pitz-Paal, Robert
- Subjects
field control ,Line-Focus ,transient ,CSP ,nowcasting ,Loop Valve ,optimization ,Simulation - Published
- 2016
13. Simulation of Potential Enhancements in Parabolic Trough Solar Field Start-up Controllers using Nowcasting Systems.
- Author
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Noureldin, Kareem, Hirsch, Tobias, Nouri, Bijan, and Yasser, Zeyad
- Subjects
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PARABOLIC troughs , *SOLAR power plants , *RADIATION - Abstract
The yield of solar thermal power plants is strongly affected by disturbances in the irradiation condition through passing clouds. This effect is even more prominent when the clouds shade the solar field only partially as the irradiance situation cannot be fully measured by few measurement points in the field. In this paper, the benefit of using nowcasting systems to produce highly resolved irradiance maps on the field during start-up is studied. A simulation tool is used to dynamically model all the loops and piping in a reference commercial solar field. Automatic solar field controllers allow the model to operate during different situations. The performance of the field under a reference state-of-the-art controller is compared against a controller using the irradiance maps from nowcasting systems. The benefit during start-up processes is found to be significantly lower than the benefit the system makes during normal solar field operation. However, there is more potential shown for more advanced controllers, like model-predictive control. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. Development of Training Simulator Software for Molten Salt Parabolic Trough Test Platform.
- Author
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Hoegemann, Daniel, Noureldin, Kareem, Bamberger, Florian, and Hirsch, Tobias
- Subjects
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PARABOLIC troughs , *SYNTHETIC training devices , *FUSED salts , *HUMAN-machine systems , *WORKING fluids , *FACTORY design & construction - Abstract
Operators of a solar-thermal power plant bear a high responsibility as they are in charge of the plant integrity, the safety of staff and optimal performance. At the same time, the complexity of such plants is very high. Thus, skilled operators are needed to understand what they do and, especially, how to react in non-standard plant conditions. Training the operators for these situations is very important for trouble-free operation. Those items become particularly crucial for testing of parabolic trough plants with molten salt as working fluid, as they inherit the danger of HTF freezing at normal ambient conditions. DLR developed a training simulation software as a platform to train the operators in dealing with various scenarios and test automation concepts for plant control for the test facility in the HPS2 project. The simulator software features a detailed model for transient simulation of the solar field based on DLR’s Virtual Solar Field (VSF), a simulator management system and a human-machine interface (HMI). VSF communicates via a standard TCP/IP interface with the simulator management. The plant model features detailed modelling of the hydraulic network and storage system, alarm functions and control logics derived from the functionality of the test plant. The HMI is designed according to the real process control software. Simulations with measured weather data validated the correct behavior of the physical models. To understand the behavior of the plant, the plant model can be completely manually operated. Various weather scenarios can be loaded to show difficulties of transient situations, like a sudden direct normal irradiation (DNI) rise or drop. This enables the trainer to show real operation scenarios of the molten salt plant during the training course without endangering the test facility. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Power-to-Heat in CSP Systems for Capacity Expansion.
- Author
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Giuliano, Stefano, Puppe, Michael, and Noureldin, Kareem
- Subjects
FUSED salts ,PLANT capacity ,HEAT storage ,ENERGY storage ,SOLAR power plants - Abstract
The objective of this paper is the evaluation of trends when a power-to-heat system with electrical heaters is integrated to a molten salt solar tower to additionally charge the thermal energy storage system and to expand the capacity of the CSP plant. Therefore a techno-economic analysis was carried out considering several economical and technical boundary conditions. The results show a significant impact on the availability of excess electricity and its cost. Depending on system layout and the cost of the used electricity the overall LCOE of such plants can be reduced by up to 25%. Therefore such power-to-heat systems can offer an economic and strategic benefit to solar thermal power plants. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
16. Modelling an Automatic Controller for Parabolic Trough Solar Fields under Realistic Weather Conditions.
- Author
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Noureldin, Kareem, Hirsch, Tobias, Kuhn, Pascal, Nouri, Bijan, Yasser, Zeyad, and Pitz-Paal, Robert
- Subjects
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AUTOMATIC control systems , *PARABOLIC troughs , *POWER plants , *FLUID flow , *SOLAR energy , *NOWCASTING (Meteorology) - Abstract
Controlling parabolic trough solar thermal power plants during transient events, such as passing clouds, is challenging for the power plant operators. Solar field controllers try to operate the field with the suitable fluid mass flow to reduce any waste of solar irradiation under very different weather and operational conditions. However, finding the optimal operation trajectory is not possible or guaranteed due to the lack of information about many influencing parameters in the solar field including, for example, effect of spatial variation of irradiance and flow maldistribution in the field. In this paper, the in-house transient simulation tool, the Virtual Solar Field (VSF) is used to test full-sized solar power plants under realistic weather conditions. Automatic field controllers have been developed with the help of our industrial partners to act as reference for further developments in field control. Thus, the VSF can estimate the potential benefit of advanced controllers using, for instance, nowcasting systems provided by cloud cameras, as well as loop control valves to manipulate the flow control in individual loops. It is shown how the VSF can act as a platform to test different control strategies and provide assessments of the detailed performance of the controller with different control components. The implemented automatic field controllers proved to be robust for different irradiance types and, hence, can be used as basis for further analysis. In addition, the controller can be instructed to dump some of the incident solar energy through defocusing in cases when the available solar energy is higher than the energy consumption by the power block and storage. In summary, VSF allows the developers of solar field controllers to test their implementations under different weather conditions and provide accurate assessment without disturbing power plant operation and before investing in new technologies, for instance nowcasting systems. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. Modelling and optimization of transient processes in parabolic trough power plants with single-phase heat transfer medium (Motivation)
- Author
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Noureldin, Kareem and Hirsch, Tobias
- Subjects
Linienfokussierende Systeme ,PTC Simulation Transient processes CSP - Abstract
The Federal Government in Germany adopted a long term “Energy Concept” with the goal to significantly reduce CO¬2 emissions by 2050. Renewable energy sources are considered the cornerstone to achieve this goal. As stated in [1], locally-produced and imported electricity from renewable energy sources are to account for 80% of the gross electricity consumption by 2050. Using molten salt single-phase heat transfer media in linear concentrating solar thermal power plants represents a very promising opportunity [2]. In addition to the increased temperature, as compared to oil-operated plants, the heated fluid could be directly stored to achieve longer operation periods. On the other hand, shut down and maintenance costs are significantly higher for solar fields with molten salt as the heat transfer fluid. That is due to the risk of fluid solidification or tube corrosion as the fluid temperatures drop or rise, respectively, beyond certain limits. In this PhD project, it is planned to develop a model to simulate whole fields and provide control information to account for changing irradiation conditions. Simulations of transient processes for single loops and subfields have already been sought and computed, for example in [3] and [4]. However, a more flexible, efficient and robust tool is required to better investigate larger fields in a timely manner. The tool could be used to optimize the system response to passing clouds and to improve the efficiency of startup procedures. The authors seek to simulate the field using a more detailed model for the hydraulic network and the mass flow distributions among the loops. The efficient calculation of mass flow distributions and pressure drops represent a challenge for the large systems of varying temperatures and fluid properties. The PhD project runs for the upcoming 3 years and is funded by DLR and DAAD. References: [1] Federal Ministry of Economics and Technology, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Energy Concept for an Environmentally Sound, Reliable and Affordable Energy Supply, September 2010 [2] Wagner, P.H., Wittmann, M., Influence of different operation strategies on transient solar thermal power plant simulation models with molten salt as heat transfer fluid, Conference paper, SolarPACES 2013 [3] Hirsch, T., Feldhoff, J.F., Schenk, H., Start-up Modeling for Annual CSP Yield Calculations, Journal of Solar Energy Engineering, 2012, 134 [4] Giostri, A., Transient effects in linear concentrating solar thermal power plant, Dissertation, Energy Department, Politecnico Di Milano
- Published
- 2014
18. Virtual Solar Field - An Opportunity to Optimize Transient Processes in Line-Focus CSP Power Plants.
- Author
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Noureldin, Kareem, Hirsch, Tobias, and Pitz-Paal, Robert
- Subjects
- *
SOLAR energy , *SOLAR thermal energy , *HYDRAULICS , *ELECTRIC power production , *SIMULATION methods & models - Abstract
Optimizing solar field operation and control is a key factor to improve the competitiveness of line-focus solar thermal power plants. However, the risks of assessing new and innovative control strategies on operational power plants hinder such optimizations and result in applying more conservative control schemes. In this paper, we describe some applications for a whole solar field transient in-house simulation tool developed at the German Aerospace Centre (DLR), the Virtual Solar Field (VSF). The tool offers a virtual platform to simulate real solar fields while coupling the thermal and hydraulic conditions of the field with high computational efficiency. Using the tool, developers and operator can probe their control strategies and assess the potential benefits while avoiding the high risks and costs. In this paper, we study the benefits gained from controlling the loop valves and of using direct normal irradiance maps and forecasts for the field control. Loop valve control is interesting for many solar field operators since it provides a high degree of flexibility to the control of the solar field through regulating the flow rate in each loop. This improves the reaction to transient condition, such as passing clouds and field start-up in the morning. Nevertheless, due to the large number of loops and the sensitivity of the field control to the valve settings, this process needs to be automated and the effect of changing the setting of each valve on the whole field control needs to be taken into account. We used VSF to implement simple control algorithms to control the loop valves and to study the benefits that could be gained from using active loop valve control during transient conditions. Secondly, we study how using short-term highly spatially-resolved DNI forecasts provided by cloud cameras could improve the plant energy yield. Both cases show an improvement in the plant efficiency and outlet temperature stability. This paves the road for further investigations of new control strategies or for optimizations of the currently implemented ones. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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