| 1. |
- Aichmayer, Lukas, et al.
(author)
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Design and Analysis of a Solar Receiver for Micro Gas Turbine based Solar Dish Systems
- 2012
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In: Proceedings of the International SolarPACES Conference 2012. Marrakesh, Morocco. September 11-14, 2012.
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Conference paper (peer-reviewed)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.
(author)
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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
-
In: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 159, s. 184-195
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Journal article (peer-reviewed)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.
(author)
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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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In: AIP Conference Proceedings 1734. - : American Institute of Physics (AIP). - 9780735413863
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Conference paper (peer-reviewed)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.
(author)
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Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants
- 2013
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In: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 135:11, s. 113001-
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Journal article (peer-reviewed)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.
(author)
-
Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants
- 2013
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In: Proceedings of the ASME Turbo Expo 2013. San Antonio, USA. June 3-7. - : ASME. - 9780791855188
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Conference paper (peer-reviewed)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.
(author)
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Performance Improvements of the KTH High-Flux Solar Simulator
- 2017
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In: AIP Conference Proceedings 1850. - : American Institute of Physics (AIP). - 9780735415225
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Conference paper (peer-reviewed)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.
(author)
-
Preliminary design and analysis of a novel solar receiver for a micro gas-turbine based solar dish system
- 2015
-
In: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 114:4, s. 378-396
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Journal article (peer-reviewed)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.
(author)
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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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In: International Journal of Solar Energy. - : Elsevier. - 0142-5919 .- 1477-2752. ; 162, s. 248-264
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Journal article (peer-reviewed)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.
(author)
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Small Scale Hybrid Solar Power Plants for Polygeneration in Rural Areas
- 2014
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In: Energy Procedia 57. - : Elsevier. ; , s. 1536-1545
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Conference paper (peer-reviewed)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
(author)
-
Solar receiver development for gas-turbine based solar dish systems
- 2018
-
Doctoral thesis (other academic/artistic)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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| 11. |
- Aichmayer, Lukas, et al.
(author)
-
Thermo-mechanical solar receiver design and validation for a micro gas-turbine based solar dish system
- 2020
-
In: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 196
-
Journal article (peer-reviewed)abstract
- This work presents the comprehensive development of a solar receiver for the integration into a micro gas-turbine solar dish system. Special focus is placed on the thermo-mechanical design to ensure the structural integrity of all receiver components for a wide range of operating conditions. For the development, a 3-dimensional coupled multi-physics model is established and is validated using experimental data. Contrary to previous studies, the temperature of the irradiated front surface of the absorber is included in the comprehensive validation process which results in a high level of confidence in the receiver design.Finally, a full-scale solar receiver for the integration into the OMSoP solar dish system is designed and its performance determined for a wide operating range to define its safe operating envelope using the validated model. It is shown that the receiver is capable of operating at 803_C with an efficiency of 82.1% and a pressure drop of 0.3% at the nominal operating point, while at the same time functioning effectively for a wide range of off-design conditions without compromising its structural integrity. At the nominal operating point, the maximum comparison stress of the porous absorber is 5.6 MPa compared to a permissible limit of 7.4 MPa.
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| 12. |
- Aichmayer, Lukas, et al.
(author)
-
Thermoeconomic Analysis of a Solar Dish Micro Gas-Turbine Combined-Cycle Power Plant
- 2015
-
In: Energy Procedia 69. - : Elsevier. - 1876-6102. ; , s. 1089-1099
-
Conference paper (peer-reviewed)abstract
- 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.
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| 13. |
- Garrido, Jorge, et al.
(author)
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Characterization of the KTH high-flux solar simulator combining three measurement methods
- 2017
-
In: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 141, s. 2091-2099
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Journal article (peer-reviewed)abstract
- 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.
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| 14. |
- Garrido, Jorge, et al.
(author)
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Experimental and numerical performance analyses of a Dish-Stirling cavity receiver : Geometry and operating temperature studies
- 2018
-
In: Solar Energy. - : Pergamon Press. - 0038-092X .- 1471-1257. ; 170, s. 913-923
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Journal article (peer-reviewed)abstract
- 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.
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| 15. |
- Garrido, Jorge, et al.
(author)
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Experimental and numerical performance analyses of Dish-Stirling cavity receivers : Radiative property study and design
- 2019
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In: Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442 .- 1873-6785. ; 169, s. 478-488
-
Journal article (peer-reviewed)abstract
- 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.
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| 16. |
- Lanchi, Michela, et al.
(author)
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A Quasi-Steady State Model of a Solar Parabolic Dish Micro Gas Turbine Demonstration Plant
- 2022
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In: Energies. - : MDPI AG. - 1996-1073. ; 15:3
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Journal article (peer-reviewed)abstract
- In the framework of the European Optimised Microturbine Solar Power system (OMSoP) project, a novel energy system for solar electricity production was developed, based on the integration of the solar dish technology with Micro Gas Turbines (MGT). A pilot plant with a capacity of 5-7 kW(e) was realized and installed at the ENEA Casaccia site (Rome) and went under testing to validate the feasibility of the technology and improve the current design. The present work deals with the development of a quasi-state system model, built in the Engineering Equation Solver environment, composed of different modules that correspond to the main system components. The system model was used to define the optimal system parameters, to help the elaboration on an operational strategy to maximize the overall plant efficiency, and to guide the improvement of the single components in view of their optimised design. From the analysis it emerged that the system in design conditions is able to generate, in nominal conditions, 4.5 kW(e) instead of the expected 5 kW(e) due to the limitation of the stator current to 13 A, while maximum levels of 5.6 kW could be achieved by "overcharging" the high-speed generator up to 15 A and operating the MGT at the very high speed of 150 krpm. From the transient simulation of the demo system on an annual basis, the maximum average output power is 3.58 kW(e). Regarding the cycle efficiency, the annual averaged value is about 17%, whereas the target value is 21%. The improvement of the generator only does not seem to significantly increase the power output on the annual basis (3.75 kW(e) vs. 3.58 kW(e)). Differently, the improvement of the solar dish, with the upgrade of the other system components, would significantly increase the system power output to around ~10 kW(e).
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| 17. |
- Ragnolo, Gianmarco, et al.
(author)
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Technoeconomic Design of a Micro Gas-Turbine for a Solar Dish System
- 2014
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In: Proceedings of the International SolarPACES Conference 2014. Beijing, China. September 16-19. - : Elsevier.
-
Conference paper (peer-reviewed)abstract
- An integrated approach for the design of a custom-tailored hybrid solar MGT with an integrated solar receiver for the use in a small-scale solar dish unit is presented in order to overcome the inherent limitations of adapting a MGT in the desired power range to solar operation. The resulting MGT-dish equipped with the ‘optimal’ MGT shows a nominal conversion efficiency of 29.6%. Then, a thermoeconomic analysis of the entire system is performed to evaluate and compare the economic and environmental performance of the MGT-dish with a Dish-Stirling system. From an economical point of view the MGT-dish outperforms the dish-Stirling with LCoEs as low as 15.3€cts/kWhel compared to 22.4€cts/kWhel.
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| 18. |
- Spelling, James, et al.
(author)
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Thermoeconomic Evaluation of a Novel Utility-Scale Hybrid Solar Dish Micro Gas-Turbine Power Plant
- 2015
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In: Proceedings of the ASME Turbo Expo 2015. Montreal, Canada. June 15-19. - : ASME Press. - 9780791856673
-
Conference paper (peer-reviewed)abstract
- 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 collector efficiency of the solar dish with the high conversion efficiency of a combined-cycle power block. To explore the potential of the concept, its performance has been compared against a more conventional solar dish farm based on recuperated micro gas-turbines. Multi-objective optimization has been used to identify Pareto-optimal designs and examine the trade-offs between minimizing capital costs and maximizing performance. The micro gas-turbine combined-cycle layout has been shown to be promising for utility-scale applications, reducing electricity costs by 5–10%, depending on the degree of solar integration; this novel power plant layout also reduces emissions through increased conversion efficiency of the power block. However, at smaller plant sizes (outputs below 18 MWe), more traditional recuperated solar dish farms remain the most viable option.
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| 19. |
- Wang, Wujun, et al.
(author)
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Design and Validation of a Low-cost High-flux Solar Simulator using Fresnel Lens Concentrators
- 2013
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In: Proceedings of the SolarPACES 2013 International Conference. - : Elsevier. ; , s. 2221-2230
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Conference paper (peer-reviewed)abstract
- A systematic design procedure for a high flux solar simulator is presented in this paper. The 84 kWe solar simulator is based on an array of 12 commercially available xenon-arc lamps (each 7 kWe) coupled with silicone-on-glass Fresnel lenses as the optical concentrator. A ray-tracing model of the xenon lamp has been developed based on the real emitter shape and the Fresnel lens optics; simulations performed using a non-sequential Monte Carlo technique have been validated against experimental test data. The results show that 19.7 kW of radiative power is delivered on a 20 cm diameter target with and a peak flux of 6.73 MW/m2 and an electricity to radiative power efficiency of 23.4%. This research facility will be used as an experimental platform for high flux solar receiver and thermochemical reactor research, as well as for advanced high-temperature material testing.
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| 20. |
- Wang, Wujun, 1984-, et al.
(author)
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Development of a Fresnel lens based high-flux solar simulator
- 2017
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In: Solar Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0038-092X .- 1471-1257. ; 144, s. 436-444
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Journal article (peer-reviewed)abstract
- In this paper, a Fresnel lens based high flux solar simulator (HFSS) is developed for concentrating solar power research and high temperature material testing. In this design, each commercially available 7 kW(e) xenon-arc lamp is coupled with a silicone-on-glass Fresnel lenses as the optical concentrator, and 12 lamp-lens units are distributed in a circular array. In total, the power of the solar simulator can reach 84 kWe. A ray tracing model has been developed based on the real arc-emitter shape and the Fresnel lens optics for predicting the optical performance of the HFSS design. The testing result shows that the ray tracing model can predict the flux distribution on the focal plane accurately but a bit conservative in the center region. The flux distribution on the focal plane appears axisymmetric with a peak flux of 7.22 MW/m(2), and 19.7 kW of radiative power in total is delivered on a 280 mm diameter target. (C) 2017 Elsevier Ltd. All rights reserved.
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| 21. |
- Wang, Wujun, 1984-, et al.
(author)
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Integrated Design of a Hybrid Gas Turbine-Receiver Unit for a Solar Dish System
- 2014
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In: Proceedings of the International SolarPACES Conference 2014. Beijing, China. September 16-19, 2014. - : Elsevier BV.
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Conference paper (peer-reviewed)abstract
- An integrated design concept of a 25 KWel hybrid gas turbine-receiver unit is introduced in this paper. In this design, hot section; receiver, combustor and turbine, is integrated and located in the center of the unit in order to achieve a compact structure with low heat loss and cooling requirement. A ray tracing model is developed for analyzing the focal plane of the potential parabolic dish design and predicting the radiative flux boundary conditions of the receiver. An impinging cavity receiver, with a cylindrical absorber wall and a semi-spherical bottom, is chosen as the receiver for this hybrid unit. The cooling capacities of different impinging arrangements are calculated to determine the thermal boundary conditions on the cooling side. Finally, the optimal dimensions of the receiver are chosen as well as the impingement cooling design. A ‘single ring’ impinging array was found to be optimal for cooling down the wall temperature of the peak flux region to 1200 °C and provide a receiver exit temperature of 840 °C.
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| 22. |
- Wang, Wujun, 1984-, et al.
(author)
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Transient performance of an impinging receiver : An indoor experimental study
- 2018
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In: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 158, s. 193-200
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Journal article (peer-reviewed)abstract
- The impinging receiver is a new member of the cavity solar receiver family. In this paper, the transient performance of a prototype impinging receiver has been studied with the help of a Fresnel lens based solar simulator and an externally fired micro gas turbine. The impinging receiver can offer an air outlet temperature of 810 °C at an absorber temperature of 960 °C. The radiative-to-thermal efficiency is measured to be 74.1%. The absorber temperature uniformity is good but high temperature differences have been detected during the ‘cold startup’ process. The temperature changing rate of the receiver is within 3 °C/s for the startup process and 4 °C/s for the shut-down process. In order to avoid quenching effects caused by the impinging jets, the micro gas turbine should be turned off to stop the airflow when the radiative power is off.
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