| 1. |
- Aichmayer, Lukas, et al.
(författare)
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Design and Analysis of a Solar Receiver for Micro Gas Turbine based Solar Dish Systems
- 2012
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Ingår i: Proceedings of the International SolarPACES Conference 2012. Marrakesh, Morocco. September 11-14, 2012.
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Aichmayer, Lukas, et al.
(författare)
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Experimental evaluation of a novel solar receiver for a micro gas-turbine based solar dish system in the KTH high-flux solar simulator
- 2018
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 159, s. 184-195
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Aichmayer, Lukas, et al.
(författare)
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Experimental Flux Measurement of a High-Flux Solar Simulator using a Lambertian Target and a Thermopile Flux Sensor
- 2016
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Ingår i: AIP Conference Proceedings 1734. - : American Institute of Physics (AIP). - 9780735413863
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 4. |
- Aichmayer, Lukas, et al.
(författare)
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Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants
- 2013
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Ingår i: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 135:11, s. 113001-
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Tidskriftsartikel (refereegranskat)abstract
- 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%.
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| 5. |
- Aichmayer, Lukas, et al.
(författare)
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Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants
- 2013
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Ingår i: Proceedings of the ASME Turbo Expo 2013. San Antonio, USA. June 3-7. - : ASME. - 9780791855188
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Konferensbidrag (refereegranskat)abstract
- 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%.
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| 6. |
- Aichmayer, Lukas, et al.
(författare)
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Performance Improvements of the KTH High-Flux Solar Simulator
- 2017
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Ingår i: AIP Conference Proceedings 1850. - : American Institute of Physics (AIP). - 9780735415225
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 7. |
- Aichmayer, Lukas, et al.
(författare)
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Preliminary design and analysis of a novel solar receiver for a micro gas-turbine based solar dish system
- 2015
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 114:4, s. 378-396
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Aichmayer, Lukas, et al.
(författare)
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Scaling effects of a novel solar receiver for a micro gas-turbine based solar dish system
- 2018
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Ingår i: International Journal of Solar Energy. - : Elsevier. - 0142-5919 .- 1477-2752. ; 162, s. 248-264
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Aichmayer, Lukas, et al.
(författare)
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Small Scale Hybrid Solar Power Plants for Polygeneration in Rural Areas
- 2014
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Ingår i: Energy Procedia 57. - : Elsevier. ; , s. 1536-1545
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 10. |
- Aichmayer, Lukas
(författare)
-
Solar receiver development for gas-turbine based solar dish systems
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small-scale concentrating solar power plants such as micro gas-turbine based solar dish systems have the potential to harness solar energy in an effective way and supply electricity to customers in remote areas. In such systems, the solar receiver transfers the power of concentrated solar radiation to the working fluid of the power conversion cycle. It is one of the key components as it needs to operate at high temperatures to ensure a high power cycle efficiency and under high flux densities to ensure a high receiver efficiency. In order to address these challenges and to ensure efficient and reliable operation innovative designs are needed.This research work focuses on the complete development of a novel solar receiver applying a new systematic design and analysis methodology. Therefore, a comprehensive receiver design and experimental evaluation process were developed and implemented. The design process includes the identification of technical specifications and requirements, the development of receiver design tools of different investigation levels coupled with multi-objective optimization tools, the evaluation of scaling effects between tests in the KTH high-flux solar simulator and the full-scale solar dish system. As a result of the design process a representative final receiver was established with material temperatures and stresses below critical limits while respecting the design specification.The experimental evaluation includes the enhancement of the KTH high-flux solar simulator to provide stable and reliable operating conditions, the precise characterization of the radiative boundary conditions, the design of a receiver test bed recreating the operating behavior of a gas-turbine, and the final receiver testing for multiple operating points. It was shown that the prototype reaches an efficiency of 69.3% for an air outlet temperature of 800°C and a mass flow of 29.5 g/s. For a larger mass flow of 38.4 g/s a receiver efficiency of 84.8% was achieved with an air outlet temperature of 749°C.The measurement results obtained were then used for a multi-point validation of the receiver design tools, resulting in a high level of confidence in the accuracy of the tools. The validated models were then harnessed to calculate the performance of a full-scale solar receiver integrated into the OMSoP solar dish system. It was shown that a solar receiver can be designed, which delivers air at 800°C with a receiver efficiency of 82.2%.Finally, the economic potential of micro gas-turbine based solar systems was investigated and it was shown that they are ideally suited for small-scale stand-alone and off-grid applications.The results of the receiver development highlight the feasibility of using volumetric solar receivers to provide heat input to micro gas-turbine based solar dish systems and no major hurdles were found.
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