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  • 1.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Performance Improvements of the KTH High-Flux Solar Simulator2017In: AIP Conference Proceedings 1850, American Institute of Physics (AIP), 2017, Vol. 1850, article id 150001Conference paper (Refereed)
    Abstract [en]

    This paper presents the performance improvements implemented in the KTH high-flux solar simulator to deliver a total power on target closer to the working conditions of real CSP systems. Therefore, additional rectifiers were installed in the power conversion unit of the high-power lamps as well as the back reflector was coated providing more favorable spectral reflectance properties. The results of a single lamp/lens-combination show that the power on target in an aperture of 280mm in diameter was increased from 831W to 1446W while the peak flux was increased from 675kW/m² to 905kW/m².

  • 2.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Scaling effects of a novel solar receiver for a micro gas-turbine based solar dish system2018In: International Journal of Solar Energy, ISSN 0142-5919, E-ISSN 1477-2752, Vol. 162, p. 248-264Article in journal (Refereed)
    Abstract [en]

    Laboratory-scale component testing in dedicated high-flux solar simulators is a crucial step in the developmentand scale-up of concentrating solar power plants. Due to different radiative boundary conditions available inhigh-flux solar simulators and full-scale power plants the temperature and stress profiles inside the investigatedreceivers differ between these two testing platforms. The main objective of this work is to present a systematicscaling methodology for solar receivers to guarantee that experiments performed in the controlled environmentof high-flux solar simulators yield representative results when compared to full-scale tests. In this work theeffects of scaling a solar air receiver from the integration into the OMSoP full-scale micro gas-turbine based solardish system to the KTH high-flux solar simulator are investigated. Therefore, Monte Carlo ray-tracing routines ofthe solar dish concentrator and the solar simulator are developed and validated against experimental characterizationresults. The thermo-mechanical analysis of the solar receiver is based around a coupled CFD/FEManalysislinked with stochastic heat source calculations in combination with ray-tracing routines. A geneticmulti-objective optimization is performed to identify suitable receiver configurations for testing in the solarsimulator which yield representative results compared to full-scale tests. The scaling quality is evaluated using aset of performance and scaling indicators. Based on the results a suitable receiver configuration is selected forfurther investigation and experimental evaluation in the KTH high-flux solar simulator.

  • 3.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Preliminary design and analysis of a novel solar receiver for a micro gas-turbine based solar dish system2015In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 114, no 4, p. 378-396Article in journal (Refereed)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas-turbine systems, which would seem to present a number of advantages when compared with Stirling engine based systems and photovoltaic panels. In this study a solar receiver meeting the specific requirements for integration into a small-scale (10 kWel) dish-mounted hybrid solar micro gas-turbine system has been designed with a special focus on the trade-offs between efficiency, pressure drop, material utilization and economic design. A situation analysis, performed using a multi-objective optimizer, has shown that a pressurized configuration, where the solar receiver is placed before the turbine, is superior to an atmospheric configuration with the solar receiver placed after the turbine. Based on these initial design results, coupled CFD/FEM simulations have been performed, allowing detailed analysis of the designs under the expected operating conditions. The results show that the use of volumetric solar receivers to provide heat input to micro gas-turbine based solar dish systems appears to be a promising solution; with material temperatures and material stresses well below permissible limits.

  • 4.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Small Scale Hybrid Solar Power Plants for Polygeneration in Rural Areas2014In: Energy Procedia 57, Elsevier, 2014, Vol. 57, p. 1536-1545Conference paper (Refereed)
    Abstract [en]

    Small scale micro gas-turbine based hybrid solar power plants are a promising technology for supplying multiple energy services in a controllable and sustainable manner using polygeneration technologies. Compared to a conventional diesel generator based system where electricity is used as the main energy carrier, these systems show great potential to reduce costs and carbon dioxide emissions. Depending on the design, carbon dioxide emissions are reduced by around 9% and equivalent annual costs are reduced by 21% - 26%, as compared to a base polygeneration configuration where cooling services are provided centrally by an absorption chiller without integrating a solar micro gas-turbine. Compared to the system where electricity is used as the main energy carrier a reduction of equivalent annual costs of up to 20% and a reduction of carbon dioxide emissions of up to 33.5% was achieved.

  • 5.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    IMDEA Energy Institute, Spain.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermoeconomic Analysis of a Solar Dish Micro Gas-Turbine Combined-Cycle Power Plant2015In: Energy Procedia 69, Elsevier, 2015, Vol. 69, p. 1089-1099Conference paper (Refereed)
    Abstract [en]

    A novel solar power plant concept is presented, based on the use of a coupled network of hybrid solar-dish micro gas-turbines, driving a centralized heat recovery steam generator and steam-cycle, thereby seeking to combine the high efficiency of the solar dish collector with a combined-cycle power block. A 150 MWe solar power plant was designed based on this concept and compared with both a conventional combined-cycle power plant and a hybrid solar-tower combined-cycle. The solar dish combined-cycle power plant could reach higher levels of solar integration than other concepts but was shown to be more expensive with current technology; solar electricity costs are double those of the hybrid solar-tower combined cycle.

  • 6.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013In: Proceedings of the ASME Turbo Expo 2013. San Antonio, USA. June 3-7, ASME , 2013Conference paper (Refereed)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts the combined pressure drop of the recuperator and receiver is more important. The internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated, in terms of both electricity costs and carbon emissions. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20 – 35%.

  • 7.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, no 11, p. 113001-Article in journal (Refereed)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts, the combined pressure drop of the recuperator and receiver is more important. In terms of both electricity costs and carbon emissions, the internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20–35%.

  • 8.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Design and Analysis of a Solar Receiver for Micro Gas Turbine based Solar Dish Systems2012In: Proceedings of the International SolarPACES Conference 2012. Marrakesh, Morocco. September 11-14, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas turbine systems which would seem to present a number of advantages when compared with Stirling engine systems. A solar receiver meeting the specific requirements for integration into the power conversion system of the solar laboratory of the Royal Institute of Technology - which will emulate a solar dish system and is currently under construction - was designed. The simulations that have been performed utilize a heat transfer and pressure drop model coupled with a multi-objective optimizer as well as a coupled-CFD/FEM tool, allowing determination of the ideal receiver design for the expected conditions. The analysis has shown that the use of volumetric solar receivers to provide heat input to micro gas turbine based solar dish systems appears to be a promising solution; with pressurized receiver configurations as the preferred choice due to significant lower pressure drops as compared to atmospheric configurations.

  • 9.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental evaluation of a novel solar receiver for a micro gas-turbine based solar dish system in the KTH high-flux solar simulator2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 159, p. 184-195Article in journal (Refereed)
    Abstract [en]

    This work presents the experimental evaluation of a novel pressurized high-temperature solar air receiver for the integration into a micro gas-turbine solar dish system reaching an air outlet temperature of 800°C. The experiments are conducted in the controlled environment of the KTH high-flux solar simulator with well-defined radiative boundary conditions. Special focus is placed on providing detailed information to enable the validation of numerical models. The solar receiver performance is evaluated for a range of operating points and monitored using multiple point measurements. The porous absorber front surface temperature is measured continuously as it is one of the most critical components for the receiver performance and model validation. Additionally, pyrometer line measurements of the absorber and glass window are taken for each operating point. The experiments highlight the feasibility of volumetric solar receivers for micro gas-turbine based solar dish systems and no major hurdles were found. A receiver efficiency of 84.8% was reached for an air outlet temperature of 749°C. When using a lower mass flow, an air outlet temperature of 800°C is achieved with a receiver efficiency of 69.3%. At the same time, all material temperatures remain below permissible limits and no deterioration of the porous absorber is found.

  • 10.
    Aichmayer, Lukas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Garrido, Jorge
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental Flux Measurement of a High-Flux Solar Simulator using a Lambertian Target and a Thermopile Flux Sensor2016In: AIP Conference Proceedings 1734, American Institute of Physics (AIP), 2016, Vol. 1734, article id 130001Conference paper (Refereed)
    Abstract [en]

    A measurement system for the experimental determination of the flux distribution at the focal plane of the KTH high-flux solar simulator was designed and implemented. It is based on a water-cooled Lambertian target and a thermopile flux sensor placed close to the focal point of the solar simulator. Correction factors to account for systematic effects were determined and an uncertainty analysis was performed. The measurement system was successfully used to evaluate the flux distribution of a single lamp/lens-arrangement with a peak flux of 675kW/m².

  • 11.
    Arnaudo, Monica
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Zaalouk, O. A.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Techno-economic Analysis of Integrated Energy Systems at Urban District Level - A Swedish Case Study2018In: Energy Procedia, Elsevier, 2018, p. 286-296Conference paper (Refereed)
    Abstract [en]

    Within the Nordic countries, distributed heat and power supply technologies, like domestic scale heat pumps and photovoltaics, are challenging the current centralized district energy infrastructure. An increasing number of customers decide to disconnect from the traditional heating network by comparing the bill to the potential economic savings which can be generated by a residential heat pump system. However, this approach can be considered valid only on a short-term perspective. This paper presents a new approach to compare the techno-economic performance of alternative technologies, based on their lifetime average cost of generation. The proposed analysis is able to determine the optimal energy infrastructure at urban district level. Within this solution, operators, city planners and users will have a solid reference for their decision making process on resources investment. From a first step analysis of a few Swedish case studies, it was found that a district heating based system is more techno-economically efficient compared to the distributed alternative. By comparing the district heating production cost to its final price, a significant profit margin for the utility was qualitatively highlighted. Thus, from a customer perspective, on the medium run, the district heating tariff can be adapted and the estimated savings from switching to a residential heat pump system can be nullified.

  • 12.
    Ayele, Getnet Tadesse
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. IMT Atlantique, Department of Energy Systems and Environment, GEPEA, UBL, F-44307 Nantes, France.
    Haurant, Pierrick
    IMT Atlantique.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Lacarrière, Bruno
    IMT Atlantique.
    An extended energy hub approach for load flow analysis of highly coupled district energy networks: Illustration with electricity and heating2018In: Applied Energy, Vol. 212, p. 850-867Article in journal (Refereed)
    Abstract [en]

    Energy systems at district/urban level are getting more complex and diversified from time to time. Different energy carriers are coupled each other to meet various types of energy demands. The conventional way of analyzing energy networks independently does not reflect the true nature of the coupled networks. One of such a promising coupled multi-carrier energy system (MCES) is the combination of district heating and electricity networks. The coupling between these two networks is increasing due to the integration of co– and poly-generation technologies at the distribution networks. Recent literatures tried to address a load flow analysis for lightly coupled networks by formulating case-specific load flow models. This paper presents a more general and flexible tool developed using Matlab® which can be used to conduct the load flow analysis of highly coupled electricity and heating networks. An energy hub concept is extended further to formulate a general model in which local generations and detailed network parameters of MCES can be taken into account. Coupled heating and electricity networks are modeled in detail for illustration. The flexibility and generality of the model are then tested by considering case studies with different network topologies (tree and meshed). A comparison is also made with a model used in recent literature. The results show that the proposed model is more accurate. The main contribution of this paper can be summarized by the following five points: (1) Coupling matrices are used to relate network power flow equations of different energy carriers; (2) Hybrid hydraulic head and pipe flow equations are used to develop the hydraulic model which can be applied for both types of tree and meshed heating networks with the possibility of pumping units; (3) A general thermal model that relates steady state temperature drops and mass flow rates, even during change of flow direction, is developed for the heating network; (4) The electricity network is modeled with the possibility of tap changing transformers; (5) The overall system of equations are solved as a single problem using Newton-Raphson iterative method.

  • 13.
    Ayele, Getnet Tadesse
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. CNRS, UMR 6144, GEPEA, IMT Atlantique, F-44307 Nantes, France..
    Mabrouk, Mohamed Tahar
    CNRS, UMR 6144, GEPEA, IMT Atlantique, F-44307 Nantes, France..
    Haurant, Pierrick
    CNRS, UMR 6144, GEPEA, IMT Atlantique, F-44307 Nantes, France..
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. KTH Royal Inst Technol, Dept Energy Technol, S-10044 Stockholm, Sweden..
    Lacarriere, Bruno
    CNRS, UMR 6144, GEPEA, IMT Atlantique, F-44307 Nantes, France..
    Optimal placement and sizing of heat pumps and heat only boilers in a coupled electricity and heating networks2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 182, p. 122-134Article in journal (Refereed)
    Abstract [en]

    Multi-energy systems are reported to have a better environmental and economic performance relative to the conventional, single-carrier, energy systems. Electrification of district heating networks using heat pumps and combined heat and power technologies is one such example. Due to lack of suitable modelling tools, however, the sizing and optimal placement of heat pumps is always done only from the heating network point of view which sometimes compromises the electricity network. This paper proposes an integrated optimization algorithm to overcome such limitation. A load flow model based on an extended energy hub approach is combined with a nested particle swarm optimization algorithm. A waste to energy combined heat and power plant, heat pumps (HPs), heat only boiler (HOB), solar photovoltaic, wind turbines and imports from the neighborhood grids are considered in the case studies. The results show that optimal placement and sizing of HPs and a HOB using the proposed methodology avoids an unacceptable voltage profiles and overloading of the electricity distribution network, which could arise while optimizing only from the heating network point of view. It also shows that up to 41.2% of the electric loss and 5% of the overall operating cost could be saved.

  • 14.
    Ayele, Getnet Tadesse
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. IMT Atlantique, Department of Energy Systems and Environment.
    Mabrouk, Mohamed Tahar
    IMT Atlantique, Department of Energy Systems and Environment.
    Haurant, Pierrick
    IMT Atlantique, Department of Energy Systems and Environment.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lacarrière, Bruno
    IMT Atlantique, Department of Energy Systems and Environment.
    Pseudo-dynamic simulation on a district energy system made of coupling technologies2018In: Proceedings of ECOS 2018 - the 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems June 17-22, 2018, Guimarães, PORTUGAL, University of Minho , 2018Conference paper (Refereed)
    Abstract [en]

    As part of an effort towards the future smart energy system, integration of different distributed generation technologies is proposed in literature. These technologies include heat pumps, gas boilers, combined heat and power (CHP) plants, solar photo-voltaic (PV) and so on. Some of these technologies couple different energy carriers in which case the independent analysis of each network could lead to unrealistic results. Optimization of heat pumps and CHP plants in coupled electricity and heating network, for example, needs consideration of both networks’ parameters in order to get results that are optimal in both networks. The first step in such optimization process is to have a load flow model (as an equality constraint) for the two coupled networks. Even though many researchers tried to address optimization of energy mixes at a district level, they did not consider the details of network parameters. Too little has been done to investigate the effect of different distributed generation technologies on the operational parameters of different energy networks. This paper deals with a pseudo-dynamic simulation of a district energy system that consists of coupled electricity and heating networks. The details of transmission line and pipe parameters together with the coupling devices are modelled using an extended energy hub approach. A network of six energy hubs with different distributed generation technologies such as heat pump, gas boiler, CHP and Solar PV is considered in the simulation. Time series data for demands and generations at different hubs are used on hourly basis. The CHP and heat pumps are scheduled to operate in certain period of the year while the PV output follows the annual solar radiation. Annual pseudo-dynamic load flow simulation is done to see how the operational parameters and power losses in the network vary with hourly changes in demands, generations and loading of coupling technologies.

  • 15.
    Ayele, Getnet Tadesse
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mabrouk, Mohamed Tahar
    IMT Atlantique - DSEE - Département Systèmes énergétiques et environnement.
    Haurant, Pierrick
    IMT Atlantique - DSEE - Département Systèmes énergétiques et environnement.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Lacarrière, Bruno
    IMT Atlantique - DSEE - Département Systèmes énergétiques et environnement.
    Santarelli, Massimo
    Polito - Politecnico di Torino.
    Exergy analysis and thermo-economic optimization of a district heating network with solar- photovoltaic and heat pumps2019In: Proceedings of the 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems / [ed] Wojciech Stanek, Paweł Gładysz, Sebastian Werle, Wojciech Adamczyk, 2019Conference paper (Refereed)
    Abstract [en]

    Electrification of district heating networks, especially using heat pumps, is widely recommended in literature. Installing heat pumps affects both electricity and heating networks. Due to lack of suitable modelling tools, size optimization of heat pumps in the heating network with the full consideration of the electric distribution network is not well addressed in literature. This paper presents an optimization of a district heating network consisting of solar photovoltaic and heat pumps with the consideration of the detail parameters of heating and electric distribution networks. An extended energy hub approach is used to model the energy system. Exergy and energy analyses are applied to identify and isolate lossy branches in a meshed heating network. Both methods resulted into the same reduced topology. Particle swarm optimization is then applied on the reduced topology in order to find out the most economical temperature profiles and size of distributed heat pumps. The thermo-economic results are found to be highly influenced by the heat demand distribution, the power loss in both electric and heat distribution network, the cost of generation, the temperature limits and the coupling effect of the heat pumps.

  • 16. Benmakhlouf, Y.
    et al.
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Wallmander, J.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A methodology to assess the market potential and identify most promising business cases for small scale CSP plants with thermal energy storage2019In: AIP Conference Proceedings, American Institute of Physics (AIP), 2019, Vol. 2126, article id 130001Conference paper (Refereed)
    Abstract [en]

    This study presents a methodology to quantify the market potential for a novel distributed CSP technology with thermal energy technology. The system in question relies on the Stirling engine for power production, which is fed by heat collected from a heliostat field and stored in an integrated latent heat storage unit. Selected countries in the MENA region are investigated to identify best prospective business cases for such a technology. With a global market potential above 40 GW in the whole MENA, industrial sectors such as mining and cement hold the best prospects in terms of market share. The achievable costs of generation vary depending on the DNI of the sites considered but prove to be lower compared with conventional distributed generation (diesel gensets or PV-BEES). However, several countries in the MENA, although having high DNI resource, still offer low electricity utility prices to industrial customers for distributed CSP to become competitive with on-grid electricity procurement. A scenario analysis coupled with a multi criteria selection of the optimal business case quantifies the amount of subsidies necessary to reach competitiveness.

  • 17.
    Brodin, Staffan
    et al.
    Volvo Aero.
    Steen, Jonas
    Volvo Aero.
    Edin, Niklas
    Volvo Aero.
    Ljunkrona, Ingegerd
    Volvo Aero.
    Laumert, Björn
    Volvo Aero.
    Vinci Engine Development Testing, a Summary of Turbine Testing Results2005Conference paper (Refereed)
  • 18. Christoph, Richter
    et al.
    Ferruzza, Davide
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Dinter, Frank
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Haglind, Fredrik
    Identification of optimum molten salts for use as heat transfer fluids in parabolic trough CSP plants. A techno-economic comparative optimization2017In: AIP Conference Proceedings, ISSN 0094-243X, E-ISSN 1551-7616Article in journal (Refereed)
    Abstract [en]

    Parabolic trough power plants using thermal oil as heat transfer fluid are the most mature concentrating solar power technology and state of the art. To further increase their efficiency and lower costs, molten salts can be used as heat transfer fluid. This results in higher operating temperature differences for improved cycle efficiencies and enables direct thermal energy storage at lower costs due to omission of the oil-to-salt heat exchanger and the need for smaller storage sizes. As a variety of salts are available to choose from, this study uses a multi-objective optimization to identify the most suitable heat transfer fluid for three locations in South Africa, Spain and Chile. The lowest values for the levelized costs of electricity (LCOE) can be found in Chile using Solar Salt as heat transfer fluid (75.0 $/MWhe). Generally, Solar Salt offers the lowest LCOE values followed by thermal oil and Hitec. The results also suggest that the choice of the heat transfer fluid is dependent on the direct normal irradiance (DNI) at each location. Thermal oil is competitive with Solar Salt in small systems at locations with low DNI values, whereas Hitec can be cheaper than thermal oil in large systems at locations with high DNI. Furthermore, it is also investigated at which freeze alert temperature set point the activation of the freeze protection system is optimal. The results indicate that this temperature should be chosen close to the solar field inlet temperature for small systems, while it can be lowered significantly for large systems to reduce electricity consumption from the freeze protection system.

  • 19. Ferruzza, D.
    et al.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Basaran, Ibrahim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Haglind, F.
    Start-up performance of parabolic trough concentrating solar power plants2017In: SOLARPACES 2016: International Conference on Concentrating Solar Power and Chemical Energy Systems, American Institute of Physics (AIP), 2017, Vol. 1850, article id 160008Conference paper (Refereed)
    Abstract [en]

    Concentrating solar power plants, even though they can be integrated with thermal energy storage, are still subjected to cyclic start-up and shut-downs. As a consequence, in order to maximize their profitability and performance, the flexibility with respect to transient operations is essential. In this regard, two of the key components identified are the steam generation system and steam turbine. In general it is desirable to have fast ramp-up rates during the start-up of a power plant. However ramp-up rates are limited by, among other things, thermal stresses, which if high enough can compromise the life of the components. Moreover, from an operability perspective it might not be optimal to have designs for the highest heating rates, as there may be other components limiting the power plant start-up. Therefore, it is important to look at the interaction between the steam turbine and steam generator to determine the optimal ramp rates. This paper presents a methodology to account for thermal stresses limitations during the power plant start up, aiming at identifying which components limit the ramp rates. A detailed dynamic model of a parabolic trough power plant was developed and integrated with a control strategy to account for the start-up limitations of both the turbine and steam generator. The models have been introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results indicated that for each application, an optimal heating rates range can be identified. For the specific case presented in the paper, an optimal range of 7-10 K/min of evaporator heating rate can result in a 1.7-2.1% increase in electricity production compared to a slower component (4 K/min).

  • 20. Ferruzza, D.
    et al.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Haglind, F.
    Impact of steam generator start-up limitations on the performance of a parabolic trough solar power plant2018In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 169, p. 255-263Article in journal (Refereed)
    Abstract [en]

    Concentrating solar power plants are an attractive option in the renewable energy generation market. The possibility of integrating relatively cheap forms of energy storage makes them a desirable solution when power generation must be readily available at any time of the day. Solar power plants typically start-up and shut down every day, so in order to maximize their profitability, it is necessary to increase their flexibility in transient operation and to initiate power generation as rapidly as possible. Two of the key components are the steam generator and steam turbine and the rates at which they can reach operational speed are limited by thermo-mechanical constraints. This paper presents an analysis of the effects of the thermal stress limitations of the steam generator and steam turbine on the power plant start-up, and quantifies their impact on the economy of the system. A dynamic model of a parabolic trough power plant was developed and integrated with a logic controller to identify start-up limitations, and subsequently the dynamic model was integrated in a techno-economic tool previously developed by the authors. The plant was analysed under two different operating strategies, namely solar-driven and peak-load. The results indicate that for steam generator hot start-ups, a 1.5% increase in peak-load electricity production would be achieved by doubling the maximum allowable heating rate of the evaporator. No useful increase would be achieved by increasing the rates beyond a limit of 7–8 K/min, as the turbine would then be the main limiting component during start-up. Similar conclusions can be drawn for the solar-driven case, for which the solar field and the energy source availability would pose the major constraint when starting up the steam generator system.

  • 21.
    Ferruzza, Davide
    et al.
    Tech Univ Denmark, Dept Mech Engn, Nils Koppels Alle,Bldg 403, DK-2800 Lyngby, Denmark..
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Haglind, Fredrik
    Tech Univ Denmark, Dept Mech Engn, Nils Koppels Alle,Bldg 403, DK-2800 Lyngby, Denmark..
    Optimal start-up operating strategies for gas-boosted parabolic trough solar power plants2018In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 176, p. 589-603Article in journal (Refereed)
    Abstract [en]

    Concentrating solar power plants are taking an increasing share in the renewable energy generation market. Parabolic trough is one of such technologies and the most commercially mature. However, this technology still suffers from technical challenges that need to be addressed. As these power plants experience daily start-up procedures, the optimal performance in transient operation needs to be considered. This paper presents a performance based modelling tool for a gas-boosted parabolic trough power plant. The objective of the paper is to define an optimal operational strategy of the power plant start-up procedure with the aim of minimizing its fuel consumption while at the same time maximizing its electric energy output, taking into account all the thermo-mechanical constraints involved in the procedure. Heating rate constraints of the steam generator and the booster heater, and the steam turbine start-up schedule were considered. The simulation model was developed based on a power plant located near Abu Dhabi, and was validated against real operational data with a maximum integral relative deviation of 4.3% for gross electric energy production. A multi-objective optimization was performed for a typical operating week during winter and spring weather conditions. The results suggest that in order to minimize the fuel consumption and at the same time maximize the electric energy production, an evaporator heating rate of 6 K/min is an optimal value both for winter and spring conditions.

  • 22.
    Fridh, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Forced Response in axial turbines under the influence of partial admission2012In: ASME Turbo Expo 2012 - Turbine Technical Conference and Exposition, Copenhagen, June 11-15, 2012: Volume 7, Issue PARTS A AND B, 2012, ASME Press, 2012, p. 1419-1429Conference paper (Refereed)
    Abstract [en]

    High cycle fatigue (HCF) due to unforeseen excitation frequencies or due to under predicted force magnitudes, or a combination of both causes control stage failures for steam turbine stakeholders. The objectives of this paper is to provide an extended design criteria toolbox and validation data for control stage design based on experimental data, with the aim to decrease HCF incidents for partial admission turbines. The upstream rotor in a two stage air test turbine is instrumented with pressure transducers and strain gauges. Admission degrees stretching from 28.6% to 100% as one or two admission arcs are simulated by blocking segmental arcs immediately upstream of first stator vanes by aerodynamically shaped filling blocks. Sweeps across a speed range from 50 to 105% of design speed are performed at constant turbine pressure ratio during simultaneous high speed acquisition. A forced response analysis is performed and results presented in Campbell diagrams. Partial admission creates a large number of low engine order forced responses because of the blockage, pumping, loading and unloading processes. Combinations of the number of rotor blades and low engine order excitations are the principal sources of forced response vibrations for the turbine studied herein. Altering the stator and/or rotor pitches will change the excitation pattern. A relation between the circumferential lengths of the admitted and non-admitted arcs that dictates the excitation forces is observed that may serve as a design parameter.

  • 23.
    Fridh, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Forced Response in Axial Turbines Under the Influence of Partial Admission2013In: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 135, no 4, p. 041014-Article in journal (Refereed)
    Abstract [en]

    High cycle fatigue (HCF) due to unforeseen excitation frequencies, underestimated force magnitudes, or a combination of both causes control-stage failures for steam turbine stakeholders. This paper provides an extended design criteria toolbox, as well as validation data, for control-stage design based on experimental data to reduce HCF incidents in partial-admission turbines. The upstream rotor in a two-stage air test turbine is instrumented with pressure transducers and strain gauges. Admission degrees extend from 28.6% to 100%, as one or two admission arcs are simulated by blocking segmental arcs immediately upstream of the first stator vanes with aerodynamically shaped filling blocks. Sweeps across a speed range of 50%-105% of design speed are performed at a constant turbine pressure ratio during simultaneous high-speed acquisition. A forced-response analysis is performed and results presented in Campbell diagrams. Partial admission creates a large number of low-engine-order forced responses because of the blockage, pumping, loading, and unloading processes. Combinations of the number of rotor blades and low-engine-order excitations are the principal sources of forced-response vibrations for the turbine studied here. Altering the stator and/or rotor pitches changes the excitation pattern. We observed that a relationship between the circumferential lengths of the admitted and nonadmitted arcs dictates the excitation forces and may serve as a design parameter.

  • 24.
    Gan, Philipe Gunawan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Deutsches Zentrum für Luft- und Raumfahrt (DLR), Linder Höhe, Cologne, 51147, Germany.
    Monnerie, N.
    Brendelberger, S.
    Roeb, M.
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sattler, C.
    Modeling, simulation and economic analysis of CSP-driven solar fuel plant for diesel and gasoline production2019In: AIP Conference Proceedings, American Institute of Physics (AIP), 2019, article id 180009Conference paper (Refereed)
    Abstract [en]

    The present research focuses on modeling of solar thermal driven fuel production plant with CO2 and H2O as raw materials to produce synthetic gas (syngas) which is converted into hydrocarbons through Fischer-Tropsch process either with Fe and Co catalyst to produce diesel, gasoline and kerosene. The solar reactor uses cerium oxide (CeO2) as a metal-redox and operates at 1773 K and 1300 K for reduction and oxidation step respectively under non-stoichiometric condition. The plant is analyzed by performing a quasi-steady state simulation under boundary condition that the Fischer-Tropsch reactor should operate with the capacity factor of 0.95 or 8350 hours annually. A storage tank is used to store and regulate the flow of syngas going into the Fischer-Tropsch reactor. Sensitivity analysis is carried out, particularly on solar reactor conversion and solid-to-solid heat exchanger efficiency. Another sensitivity analysis is to combine PV and CSP as the external electricity source. The production cost is finally calculated using annuity method with constant discount rate.

  • 25.
    Garrido Galvez, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Nilsson, Martin
    Cleanergy Company.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Detailed Radiation Heat Transfer Study of a Dish-Stirling Receiver: the Impact of Cavity Wall Radiation Properties and Cavity Shapes2015In: SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS / [ed] Rajpaul, V; Richter, C, American Institute of Physics (AIP), 2015Conference paper (Refereed)
    Abstract [en]

    A detailed 3-D radiation analysis of a dish-Stirling cavity receiver is carried out to estimate the cavity steady-state temperatures in order to assess the receiver integrity, lifetime and efficiency performance. For this purpose, a parabolic dish was modeled with 5.2 m focal length, 8.84 m aperture diameter and 2.1 mrad typical surface error. Three generic cavity shapes (cylindrical, diamond-shaped and reverse-conical) with three different emissivities (0.2, 0.4 and 0.7) are studied. Worst-case scenario heat generations (total absorbed radiation), maximum steady-state temperatures and energy balances of the cavities are calculated to evaluate the receiver performance. The results show that reverse-conical cavities can significantly reduce cavity wall peak temperatures (by 40-120 K), improve the temperature evenness and decrease the radiation losses by 4-5%. Regarding radiation properties, low reflectivities present lower steady-state temperatures even for low/moderate direct solar fluxes. Due to the lower temperatures, lower total thermal losses are also expected.

  • 26.
    Garrido, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Abou-Taouk, A.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Characterization of a Stirling cavity receiver performance in the KTH high-flux solar simulator and comparison with real Dish-Stirling data2018In: AIP Conference Proceedings, American Institute of Physics Inc. , 2018Conference paper (Refereed)
    Abstract [en]

    This paper presents the experimental results of the Cleanergy's C11S solar engine-generator tested in the KTH solar simulator. The paper focuses on the analysis of the thermal performance of the cavity receiver used in the C11S module. Multiple temperature measurements were taken on the tubes of the receiver, inside the cavity and on the internal surface of the cavity. These values allowed characterizing the temperature distribution all around the cavity receiver for the validation of thermal models and the estimation of the thermal losses. Moreover, this paper shows a comparison of the operating characteristics of the C11S module under the real operating conditions and the laboratory ones. It was observed that the temperatures of the receiver in the High Flux Solar Simulator (HFSS) resemble well the real temperatures. Thereby, the KTH solar lab provides proper irradiance levels to operate solar receivers at representative working conditions.

  • 27.
    Garrido, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Abou-Taouk, Abdallah
    Cleanergy, Regnbagsgatan 6, S-41755 Gothenburg, Sweden..
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental and numerical performance analyses of a Dish-Stirling cavity receiver: Geometry and operating temperature studies2018In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 170, p. 913-923Article in journal (Refereed)
    Abstract [en]

    Higher performance cavity receivers are needed to increase the competitiveness of solar power plants. However, the design process needs to be improved with more relevant experimental and numerical analyses. Thereby, the performance of four different Dish-Stirling cavities is investigated experimentally analyzing the influence of the cavity aperture diameter and shape at various operating temperatures. Temperatures inside the cavity receiver were collected together with the electrical power produced by the engine-generator. Then, a thermal system simulation was modelled and a comprehensive multi-parameter and multi-operation validation was performed. To improve this validation, the temperature distribution across the receiver tubes was analyzed in order to relate temperatures on the irradiated region with the non-irradiated one, where thermocouples can measure. The simulations were later used to obtain cavity receiver efficiencies, temperatures and loss breakdowns. The results show that the cavity receiver must be studied in optimization processes in conjunction with the other system components. Moreover, the reverse-conical cavity was found to be more efficient than a nearly cylindrical shape. Regarding the cavity receiver thermal losses, radiation and natural convection present similar contributions in the system under study. Finally, it was found that thermocouples installed on a non-irradiated region can be used to obtain peak receiver temperatures if the measurements are rectified by a correction value proportional to the DNI.

  • 28.
    Garrido, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Abou-Taouk, Abdallah
    Azelio, Regnbagsgatan 6, S-41755 Gothenburg, Sweden..
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental and numerical performance analyses of Dish-Stirling cavity receivers: Radiative property study and design2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 169, p. 478-488Article in journal (Refereed)
    Abstract [en]

    The solar receiver performance has a direct impact on the CSP power plant performance and, thereby, its levelized cost of electricity. Improved receiver designs supported by new advanced numerical tools and experimental validation campaigns directly help to make CSP technology more competitive. This paper presents an experimental and numerical investigation of the influence of the cavity receiver radiative properties and the thermal power input on the Dish-Stirling performance. Three cavity coatings are experimentally investigated: the original cavity material (Fiberfrax 140), Pyromark 2500 and Pyro-paint 634-ZO. Moreover, simulations validated with the experimental measurements are utilized to define a higher performance cavity receiver for the Eurodish system. The results indicate that the absorptivity of the cavity should be as low as possible to increase the receiver efficiency whereas the optimum emissivity depends on the operating temperatures. If the cavity temperature is lower than the absorber temperature, low emissivities are recommended and vice-versa. All material/coatings analyzed for the cavity provide similar receiver efficiencies, being Fiberfrax 140 slightly more efficient. Finally, a total receiver efficiency of 91.5% is reached by the proposed Eurodish cavity receiver when operating under the most favorable external conditions. 

  • 29.
    Garrido, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aichmayer, Lukas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Characterization of the KTH high-flux solar simulator combining three measurement methods2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 141, p. 2091-2099Article in journal (Refereed)
    Abstract [en]

    This paper presents the characterization of the first Fresnel lens-based High-Flux Solar Simulator (HFSS) showing the evaluation of the total thermal radiative power dependent on the aperture radius at the focal plane. This result can be directly applied to calculate the thermal power input into any solar receiver tested in the KTH HFSS. Three measurement setups were implemented and their results combined to assess and verify the characterization of the solar simulator: a thermopile sensor measuring radiative flux, a CMOS camera coupled with a Lambertian target to obtain flux maps, and a calorimeter to measure the total thermal power within an area of 300×300 mm. Finally, a Monte Carlo analysis was performed to calculate the total uncertainties associated to each setup and to combine them to obtain the simulator characterization. The final result shows a peak flux of 6.8 ± 0.35 MW/m2 with a thermal power of 14.7 ± 0.75 kW within an aperture of 180 mm in diameter at the focal plane, and a thermal-electrical conversion efficiency of 25.8 ± 0.3%. It was found very good repeatability and a stable energy output from the lamps during the experiments.

  • 30.
    Garrido, Jorge
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Sjöqvist, R.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mechanical coupling behavior of a dish-Stirling receiver: Influence on the absorber tube stresses2019In: AIP Conference Proceedings, American Institute of Physics (AIP), 2019, Vol. 2126, article id 050003Conference paper (Refereed)
    Abstract [en]

    The solar receiver tubes work under the highest temperatures and heat flux conditions, being their thermo-mechanical design critical to assure a safe and durable operation. Finite Element Analyses are traditionally utilized to assess the stresses for lifetime calculations. However, the real boundary conditions for these analyses are not well known yet. Thereby, this paper presents an experimental and numerical study to determine more realistic boundary conditions. Firstly, four deflection measurements are measured simultaneously by high-accuracy laser meters. Secondly, three types of boundary conditions are simulated trying to fit the experimental deflections: fixed, elastic and remote displacement. Finally, the stresses at critical regions are compared for each simulation. The results show that, unlike fixed support, remote displacement boundary conditions can obtain realistic deflection results but must be re-adjusted for each specific support, and elastic support fails to capture the manifold rotations. Using remote displacement stress results as reference for the case under study, fixed support leads to deviations in the stresses of at least 50% whilst elastic support can provide some similar stress results.

  • 31.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Arnaudo, Monica
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Zanino, R.
    Hassar, Z.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Techno-economic Performance Evaluation of Direct Steam Generation Solar Tower Plants with Thermal Energy Storage Systems Based on High-temperature Concrete and Encapsulated Phase Change Materials2016In: SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, 2016, article id UNSP 070011Conference paper (Refereed)
    Abstract [en]

    Nowadays, direct steam generation concentrated solar tower plants suffer from the absence of a cost-effective thermal energy storage integration. In this study, the prefeasibility of a combined sensible and latent thermal energy storage configuration has been performed from thermodynamic and economic standpoints as a potential storage option. The main advantage of such concept with respect to only sensible or only latent choices is related to the possibility to minimize the thermal losses during system charge and discharge processes by reducing the temperature and pressure drops occurring all along the heat transfer process. Thermodynamic models, heat transfer models, plant integration and control strategies for both a pressurized tank filled with sphere-encapsulated salts and high temperature concrete storage blocks were developed within KTH in-house tool DYESOPT for power plant performance modeling. Once implemented, cross-validated and integrated the new storage model in an existing DYESOPT power plant layout, a sensitivity analysis with regards of storage, solar field and power block sizes was performed to determine the potential impact of integrating the proposed concept. Even for a storage cost figure of 50 USD/kWh, it was found that the integration of the proposed storage configuration can enhance the performance of the power plants by augmenting its availability and reducing its levelized cost of electricity. As expected, it was also found that the benefits are greater for the cases of smaller power block sizes. Specifically, for a power block of 80 MWe a reduction in levelized electricity costs of 8% was estimated together with an increase in capacity factor by 30%, whereas for a power block of 126 MWe the benefits found were a 1.5% cost reduction and 16% availability increase.

  • 32.
    Guedez, Rafael Eduardo
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, J.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing the profitability of solar tower power plants through thermoeconomic analysis based on multi-objective optimization2015In: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014, 2015, Vol. 69, p. 1277-1286Conference paper (Refereed)
    Abstract [en]

    Solar tower power plants with integrated thermal energy storage units represent one of the most promising technologies for enhancing the economic viability of concentrating solar power in the short term. Tower systems allow higher concentration ratios to be achieved, which in turn means higher fluid operating temperatures and thus higher power cycle efficiencies. Moreover, the integration of storage allows power production to be shifted from times where there is low demand to periods where electricity prices are higher, potentially enhancing the profitability of the plant despite representing an additional upfront cost. The variable nature of the solar resource and the myriad potential roles that storage can assume, together with the complexity of enhancing the synergies between the three blocks: the solar field, the storage block and power block, make the design of these power plants a challenging process. This paper introduces a comprehensive methodology for designing solar tower power plants based on a thermoeconomic approach that allows the true optimum trade-off curves between cost, profitability and investment to be identified while simultaneously considering several operating strategies as well as varying critical design parameters in each of the aforementioned blocks. The methodology is presented by means of analyzing the design of a power plant for the region of Seville. For this location, results show that similar profits, measured in terms of the internal rate of return, can be achieved from different power plant configurations in terms of sizing and operating strategy, each associated to different investments. In particular, optimum configurations found corresponded to larger power blocks with medium-to-large solar field and storage blocks that allow the plants to operate continuously throughout the day and be shut down during midnight. Moreover, it is shown that for a fixed power block size it can also be economically interesting to consider smaller storage units and adopt instead a peaking strategy, as this can still be profitable whilst representing a lower investment, thus lower risk.

  • 33.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ferruzza, Davide
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Arnaudo, Monica
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Rodriguez, Ivette
    Perez-Segarra, Carlos D.
    Hassar, Zhor
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Techno-economic Performance Evaluation of Solar Tower Plants with Integrated Multi-layered PCM Thermocline Thermal Energy Storage - A Comparative Study to Conventional Two-tank Storage Systems2016In: SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, American Institute of Physics (AIP), 2016, article id UNSP 070012Conference paper (Refereed)
    Abstract [en]

    Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multi-layered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multi-layered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multi-layered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the two-tier South African tariff scheme.

  • 34.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Larchet, Kevin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Dent, Jolyon
    Green, Adam
    Hassar, Zhor
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Techno-Economic Analysis Of Hybrid Concentrating Solar Power And Solar Photovoltaic Power Plants For Firm Power In Morocco2016In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986Article in journal (Refereed)
    Abstract [en]

    The present study evaluates the optimum configurations and operating strategies of hybrid concentrating solar power and solar photovoltaic power plants for minimizing levelized costs of electricity. These configurations were also required to meet specific design objectives as provided by competitive bid tenders, such as power plant size and operating hours, for a suitable location near Midelt, Morocco. A detailed techno-economic model of the hybrid plant was developed at KTH’s in-house optimization tool DYESOPT, which allows power plant evaluation by means of technical and economic performance indicators. Results show that hybrid plants are able to achieve higher capacity factors. It is also confirmed that, under current cost estimates, hybridization enables a lower cost solution for a given high capacity factor objective than what is achievable either with stand-alone concentrating solar power or solar photovoltaic power plants, respectively. The analysis highlights synergies among the technologies and shows the relation and influence between sizing and operation of their critical components. Main challenges for successful hybridization are also raised together with recommendations for addressing them. Lastly, optimum configurations found for different tender conditions are compared and a brief discussion section at the end is introduced to highlight the relevance of adequate policy design and its impact on the work of project developers for proposing the most competitive solutions

  • 35.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing the Economic Competitiveness of Concentrating Solar Power Plants through an Innovative Integrated Solar Combined-Cycle with Thermal Energy Storage2014In: Proceedings of the ASME TurboExpo 2014, 2014, Vol. 3AConference paper (Refereed)
    Abstract [en]

    The present work deals with the thermoeconomic analysis of an innovative combined power cycle consisting of a molten- salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas- turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine power plants and it is shown that, under specific peaking operating strategies, the innovative concept can not only perform better from an environmental standpoint but also economically.

  • 36.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage2015In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 137, no 2Article in journal (Refereed)
    Abstract [en]

    The operation of steam turbine units in solar thermal power plants is very different than in conventional base-load plants. Due to the variability of the solar resource, much higher frequencies of plant start-ups are encountered. This study provides an insight to the influence of thermal energy storage (TES) integration on the typical cycling operation of solar thermal power plants. It is demonstrated that the integration of storage leads to significant reductions in the annual number of turbine starts and is thus beneficial to the turbine lifetime. At the same time, the effects of storage integration on the electricity costs are analyzed to ensure that the designs remain economically competitive. Large storage capacities, can allow the plant to be shifted from a daily starting regime to one where less than 20 plant starts occur annually. Additionally, the concept of equivalent operating hours (EOHs) is used to further analyze the direct impact of storage integration on the maintenance planning of the turbine units.

  • 37.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimization of Thermal Energy Storage Integration Strategies for Peak Power Production by Concentrating Solar Power Plants2014In: PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE, 2014, Vol. 49, p. 1642-1651Conference paper (Refereed)
    Abstract [en]

    The integration of thermal energy storage systems in concentrating solar thermal power plants allows power production to be shifted from times where there is low demand to periods where electricity prices are higher. Although increasing the total investment, thermal energy storage can therefore enhance profitability of the solar power plant. The present study presents optimum power plant configurations for a given location considering different price-based grid integration strategies. Such optimum plant configurations were determined using a thermo-economic optimization approach where the operating strategy was set such that electricity was generated once the market price exceeds a given price level, defined as the minimum price selling indicator. Plants were optimized for different indicator values to cover designs from base load and peak power production. For each of these price-operating strategies, optimum plant configurations were found by varying two solar-related design parameters, namely the solar multiple and the storage size, whilst simultaneously evaluating the economic performance of each design. Finally, an economic analysis was performed for each of the optimum power plants, assuming financial conditions throughout the lifetime of the power plant. Results show that the optimum plant configurations vary with respect to the chosen operating strategy. Optimum configurations for peak power production yielded relatively smaller storage units than that of the optimum baseload plants. Furthermore, the study demonstrates that under current cost estimations, and for the specified location, concentrating solar thermal power is not an attractive option for utility-grid investors. However, it is shown that when considering a reduction in investment costs or the possibility of having renewable electricity incentives such as the investment tax credit treasury cash grant, concentrating solar thermal power plants can become an economically viable technology.

  • 38.
    Guedez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Conde, Inés
    Gas Natural Fenosa Engineering.
    Ferragut, Francisco
    Gas Natural Fenosa Engineering.
    Callaba, Irene
    Gas Natural Fenosa Engineering.
    Spelling, James
    IMDEA .
    Hassar, Zhor
    Total New Energies.
    Perez-Segarra, Carlos David
    UPC.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A Methodology for Determining Optimum Solar Tower Plant Configurations and Operating Strategies to Maximize Profits Based on Hourly Electricity Market Prices and Tariffs2016In: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 138, no 2, article id 021006Article in journal (Refereed)
    Abstract [en]

    The present study analyzes the influence that market conditions have on determining optimum molten salt solar tower plants with storage that maximizes profits (in terms of plant configuration, sizing, and operation) for a location in South Africa. Three different scenarios based on incentive programs and local wholesale electricity prices are considered. A multi-objective optimization modeling approach was followed, showing the tradeoff curves between minimizing investment and maximizing profits when varying critical size-related parameters (such as nameplate capacity, solar multiple (SM), and storage capacity) together with power-cycle design and operating specifications including dynamic startup curves and different storage dispatchability strategies. Results are shown by means of a comparative analysis between optimal plants found for each scenario, highlighting the value that storage has under the current two-tier tariff scheme and the relevance of designing a suitable policy for technology development. Finally, a final analysis is performed with regard to the indicators used for economic evaluation of power plants, by comparing the differences between optimum designs found when using the levelized cost of electricity (LCoE) solely as performance indicator instead of cash-flows and profit-based indicators, such as the internal rate of return (IRR).

  • 39.
    Gupta, Sunay
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Market potential of solar thermal enhanced oil recovery-a techno-economic model for Issaran oil field in Egypt2017In: SOLARPACES 2016: International Conference on Concentrating Solar Power and Chemical Energy Systems, American Institute of Physics (AIP), 2017, article id 190001Conference paper (Refereed)
    Abstract [en]

    Solar thermal enhanced oil recovery (S-EOR) is an advanced technique of using concentrated solar power (CSP) technology to generate steam and recover oil from maturing oil reservoirs. The generated steam is injected at high pressure and temperature into the reservoir wells to facilitate oil production. There are three common methods of steam injection in enhanced oil recovery - continuous steam injection, cyclic steam stimulation (CSS) and steam assisted gravity drainage (SAGD). Conventionally, this steam is generated through natural gas (NG) fired boilers with associated greenhouse gas emissions. However, pilot projects in the USA (Coalinga, California) and Oman (Miraah, Amal) demonstrated the use of S-EOR to meet their steam requirements despite the intermittent nature of solar irradiation. Hence, conventional steam based EOR projects under the Sunbelt region can benefit from S-EOR with reduced operational expenditure (OPEX) and increased profitability in the long term, even with the initial investment required for solar equipment. S-EOR can be realized as an opportunity for countries not owning any natural gas resources to make them less energy dependent and less sensible to gas price fluctuations, and for countries owning natural gas resources to reduce their gas consumption and export it for a higher margin. In this study, firstly, the market potential of S-EOR was investigated worldwide by covering some of the major ongoing steam based EOR projects as well as future projects in pipeline. A multi-criteria analysis was performed to compare local conditions and requirements of all the oil fields based on a defined set of parameters. Secondly, a modelling approach for S-EOR was designed to identify cost reduction opportunities and optimum solar integration techniques, and the Issaran oil field in Egypt was selected for a case study to substantiate the approach. This modelling approach can be consulted to develop S-EOR projects for any steam flooding based oil fields. The model was developed for steam flooding requirements in Issaran oil field using DYESOPT, KTH's in-house tool for techno-economic modelling in CSP.

  • 40.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Ferragut, F.
    Hassar, Z.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Callaba, I.
    Pérez-Segarra, C. D.
    Buezas, I. C.
    Spelling, J.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A methodology for determining optimum solar tower plant configurations and operating strategies to maximize profits based on hourly electricity market prices and tariffs2015In: ASME 2015 9th International Conference on Energy Sustainability, ES 2015, collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum, ASME Press, 2015Conference paper (Refereed)
    Abstract [en]

    The present study analyses the influence that market conditions have on determining optimum molten salt solar tower plants with storage that maximize profits (in terms of plant configuration, sizing and operation) for a location in South Africa. Three different scenarios based on incentive programs and local wholesale electricity prices are considered. A multi-objective optimization modeling approach was followed, showing the trade-off curves between minimizing investment and maximizing profits when varying critical sizerelated parameters (such as nameplate capacity, solar multiple and storage capacity) together with power-cycle design and operating specifications including dynamic start-up curves and different storage dispatchability strategies. Results are shown by means of a comparative analysis between optimal plants found for each scenario, highlighting the value that storage has under the current two-tier tariff scheme, and the relevance of designing a suitable policy for technology development. Lastly, a final analysis is performed with regards of the indicators used for economic evaluation of power plants, by comparing the differences between optimum designs found when using the levelized cost of electricity solely as performance indicator instead of cash-flows and profit-based indicators, such as the internal rate of return.

  • 41.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Garcia, Jose Angel
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Martin, Fernando
    AF Aries Energia, Paseo Castellana 130,3th Floor, Madrid 28046, Spain..
    Wiesenberg, Ralf
    AF Aries Energia, Paseo Castellana 130,3th Floor, Madrid 28046, Spain..
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Integrated Solar Combined Cycles vs Combined Gas Turbine to Bottoming Molten Salt Tower Plants - A Techno-economic Analysis2018In: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2017) / [ed] Mancilla, R Richter, C, AMER INST PHYSICS , 2018, article id 180006-1Conference paper (Refereed)
    Abstract [en]

    The present work deals with the techno-economic analysis of a novel combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed model has been elaborated using in house simulation tools that simultaneously encompass meteorological, demand and required dispatch data. A range of possible designs are evaluated for a suitable location with both good solar resource and vast natural gas resources in order to show the trade-offs between the objectives of achieving low carbon-intensive and economically competitive designs. These were compared against more conventional integrated solar combined cycles of equivalent capacity factors. It is shown that the novel concept is worth further investigating as it is able to outperform the more conventional cycle while simultaneously offering additional flexibility to grid-operators.

  • 42.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing the Economic Competitiveness of Concentrating Solar Power Plants Through an Innovative Integrated Solar-Combined Cycle With Thermal Energy Storage2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 4, article id 041701Article in journal (Refereed)
    Abstract [en]

    The present work deals with the thermo-economic analysis of an innovative combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine (CCGT) power plants and it is shown that, under specific peaking operating strategies (P-OSs), the innovative concept cannot only perform better from an environmental standpoint but also economically.

  • 43.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermoeconomic Optimization of Solar Thermal Power Plants with Storage in High-Penetration Renewable Electricity Markets2013In: Energy Procedia, 2013, Vol. 57Conference paper (Refereed)
    Abstract [en]

    Unlike most of renewable energy technologies, solar thermal power plants with integrated thermal energy storage are able to store heat from the sun and thereby supply electricity whenever it is needed to meet the demand. This attribute makes concentrating solar power ideally suited to compensate for fluctuations in other renewable energy sources. In order to analyze this market role, three scenarios were modeled, with low, medium and high penetrations of non- dispatchable renewables (i.e. wind and solar photovoltaics). The demand that cannot be met by these variable sources is met by a solar thermal power plant with heat provided either by a solar field and storage system or a back-up gas burner. For each scenario, the size of the solar field and storage were varied in order to show the trade-off between the levelized generation costs of the system, the annual specific CO2 emissions and the share of renewable electricity generation. The results show that, regardless of the scenario, there exist optimum plant configurations with viable costs whilst simultaneously ensuring a considerable reduction in CO2 emissions. Furthermore, it is shown that the limited flexibility of the power block prevents the system from reaching higher levels of sustainability. Lastly, the results were compared with an equivalent combined cycle power plant, showing that solutions involving solar thermal power can be justified in environmental terms only if large storage units are integrated into the plants.

  • 44.
    Guédez, Rafael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Spelling, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Reducing the Number of Turbine Starts in Concentrating Solar Power Plants through the Integration of Thermal Energy Storage2013In: Proceedings of the ASME TurboExpo 2013, 2013Conference paper (Refereed)
    Abstract [en]

    The operation of steam turbine units in solar thermal power plants is very different than in conventional base-load plants. Due to the variability of the solar resource, much higher frequencies of plant start-ups are encountered. This study provides an insight to the influence of thermal energy storage integration on the typical cycling operation of solar thermal power plants. It is demonstrated that the integration of storage leads to significant reductions in the annual number of turbine starts and is thus beneficial to the turbine lifetime. At the same time, the effects of storage integration on the electricity costs are analyzed to ensure that the designs remain economically competitive. Large storage capacities, can allow the plant to be shifted from a daily starting regime to one where less than 20 plant starts occur annually. Additionally, the concept of equivalent operating hours is used to further analyze the direct impact of storage integration on the maintenance planning of the turbine units.

  • 45.
    Hansson, Linus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Larchet, Kevin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development and implementation of a dynamic TES dispatch control component in a PV-CSP techno-economic performance modelling tool2017In: AIP Conference Proceedings, American Institute of Physics (AIP), 2017, Vol. 1850, article id 160013Conference paper (Refereed)
    Abstract [en]

    The dispatchability offered by thermal energy storage (TES) in concentrated solar power (CSP) and solar hybrid plants based on such technology presents the most important difference compared to power generation based only on photovoltaics (PV). This has also been one reason for recent hybridization efforts of the two technologies and the creation of Power Purchase Agreement (PPA) payment schemes based on offering higher payment multiples during daily hours of higher (peak or priority) demand. Recent studies involving plant-level thermal energy storage control strategies are however to a large extent based on pre-determined approaches, thereby not taking into account the actual dynamics of thermal energy storage system operation. In this study, the implementation of a dynamic dispatch strategy in the form of a TRNSYS controller for hybrid PV-CSP plants in the power-plant modelling tool DYESOPT is presented. In doing this it was attempted to gauge the benefits of incorporating a day-ahead approach to dispatch control compared to a fully pre-determined approach determining hourly dispatch only once prior to annual simulation. By implementing a dynamic strategy, it was found possible to enhance technical and economic performance for CSP-only plants designed for peaking operation and featuring low values of the solar multiple. This was achieved by enhancing dispatch control, primarily by taking storage levels at the beginning of every simulation day into account. The sequential prediction of the TES level could therefore be improved, notably for evaluated plants without integrated PV, for which the predicted storage levels deviated less than when PV was present in the design. While also featuring dispatch performance gains, optimal plant configurations for hybrid PV-CSP was found to present a trade-off in economic performance in the form of an increase in break-even electricity price when using the dynamic strategy which was offset to some extent by a reduction in upfront investment cost. An increase in turbine starts for the implemented strategy however highlights that this is where further improvements can be made.

  • 46.
    Larchet, Kevin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Guédez, Rafael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gustavsson, L.
    Machirant, A.
    Hedlund, M. -L
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Enhancing economic competiveness of dish Stirling technology through production volume and localization: Case study for Morocco2017In: SOLARPACES 2016: International Conference on Concentrating Solar Power and Chemical Energy Systems, American Institute of Physics (AIP), 2017, Vol. 1850, article id 050002Conference paper (Refereed)
    Abstract [en]

    The present study quantifies the reduction in the levelized cost of electricity (LCoE) and capital expenditure (CAPEX) of a dish Stirling power plant (DSPP) through an increase in localization and unit production volume. Furthermore, the localization value of the plant is examined to determine how much investment is brought into the local economy. Ouarzazate, Morocco, was chosen as the location of the study due to the country's favorable regulatory framework with regards to solar power technologies and its established industry in the concentrating solar power (CSP) field. A detailed techno-economic model of a DSPP was developed using KTH's in-house modelling tool DYESOPT, which allows power plant evaluation by means of technical and economic performance indicators. Results on the basis of LCoE and CAPEX were compared between two different cases of production volume, examining both a minimum and maximum level of localization. Thereafter, the DSPP LCoE and localization value were compared against competing solar technologies to evaluate its competitiveness. In addition, a sensitivity analysis was conducted around key design parameters. The study confirms that the LCoE of a DSPP can be reduced to values similar to solar photovoltaic (PV) and lower than other CSP technologies. Furthermore, the investment in the local economy is far greater when compared to PV and of the same magnitude to other CSP technologies. The competiveness of a DSPP has the potential to increase further when coupled with thermal energy storage (TES), which is currently under development.

  • 47.
    Laumert, Björn
    KTH, Superseded Departments, Energy Technology.
    Aeromechanical Vibrations in Cascades2000Report (Other academic)
  • 48.
    Laumert, Björn
    KTH, Superseded Departments, Energy Technology.
    Numerical Methods for the Computation of Rotor/Stator Interaction2002Report (Other academic)
  • 49.
    Laumert, Björn
    et al.
    KTH, Superseded Departments, Energy Technology.
    Mårtensson, H.
    Fransson, Torsten H.
    KTH, Superseded Departments, Energy Technology.
    Investigation of unsteady aerodynamic blade excitation mechanisms in a transonic turbine stage - Part I: Phenomenological identification and classification2002In: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 124, no 3, p. 410-418Article in journal (Refereed)
    Abstract [en]

    Based on the results of time-dependent 3-D viscous computations the aerodynamic mechanisms that cause the unsteady pressure fluctuations on the vane and rotor blade surface of a high-pressure transonic turbine are identified and separately classified in a phenomenological manner. In order to be able to describe separately the influence of wake, potential and shock distortions on the blade surface pressure tit design operation conditions, the stator exit Mach number is increased as to enhance the shock distortions and lowered as to enhance potential anti wake distortions, In a comprehensive approach the observations from the off-design conditions are utilized to classify every major perturbation observed in the perturbation space-time maps tit design operation conditions. The spanwise variations caused by the inherent 3-D nature of the flow field and promoted by the 3-D shape of the rotor blade are addressed.

  • 50.
    Laumert, Björn
    et al.
    KTH, Superseded Departments, Energy Technology.
    Mårtensson, H.
    Fransson, Torsten H.
    KTH, Superseded Departments, Energy Technology.
    Investigation of unsteady aerodynamic blade excitation mechanisms in a transonic turbine stage - Part II: Analytical description and quantification2002In: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 124, no 3, p. 419-428Article in journal (Refereed)
    Abstract [en]

    This paper presents a study of the blade pressure perturbation levels and the resulting blade forces in a high-pressure transonic turbine stage based on 3-D time dependent viscous computations. Globally, the blade pressure unsteadiness is quantified with the RMS of the pressure perturbations integrated in both time and along the blade surface. Operation point as well as spanwise variations are addressed. Locally, the relative strength of the pressure perturbation events on the vane and rotor blade surface is investigated. To obtain information about the relative strength of events related to the blade passing frequency and higher harmonics, the pressure field is Fourier decomposed in time at different radial positions along the blade arc-length. The amplitude peaks are then related to the pressure events in space-time maps. With the help of the observations and results from the blade pressure study, the radial variations of the unsteady blade force and torque acting on a constant span blade profile section are investigated. The connection between the first and second vane passing frequency pressure amplitudes on the rotor blade surface and the resulting force and the torque amplitudes for three selected blade modes was investigated in detail. In this investigation the pressure was integrated over defined rotor blade regions to quanti,, local force contributions. Spanwise as well as operation point variations are addressed.

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