| 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. |
- Ghaem Sigarchian, Sara, et al.
(författare)
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Modeling and Analysis of a Hybrid Solar-Dish Brayton Engine
- 2012
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Ingår i: Proceedings of the International SolarPACES Conference 2012.
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Konferensbidrag (refereegranskat)abstract
- Small-scale recuperated gas turbines with a highly efficient recuperator would appear to have considerable potential to be used in solar/fossil-fuel hybrid dish systems. The hybrid solar gas turbine can be configured in several different fashions, with the key difference being the relative positions of the solar receiver and burner as well as the operation mode of the burner.Steady state and transient models have been implemented in Engineering Equation Solver and the performance of various configurations are studied and compared. Layouts in which the receiver is located before the turbine (pressurized receivers) demonstrate higher performance compared to the one in which the receiver is located after the turbine (atmospheric receivers). The variation in operation throughout the year is taken into account and the performance of the system analyzed for two different cities (Yechang in China and Bechar in Algeria, with low and high solar insolation respectively). The integration of a solar receiver into a micro gas turbine reduces the yearly fuel consumption by around 15-16% in Yechang and up to 40% in Bechar. This will result in reductions of CO2 emissions as well as leading to lower daily operating costs. The hybrid nature of the Dish-Brayton system guarantees availability of the engine to meet the electricity demand whenever it occurs, allowing the system to supply dispatchable power.
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| 3. |
- Spelling, James, 1987-, et al.
(författare)
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A Thermoeconomic Study of Low-Temperature Intercooled-Recuperated Cycles for Pure-Solar Gas-Turbine Applications
- 2012
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Ingår i: Journal of solar energy engineering. - : ASME International. - 0199-6231 .- 1528-8986. ; 134:4, s. 041015-
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Tidskriftsartikel (refereegranskat)abstract
- A dynamic model of a megawatt-scale low-temperature intercooled-recuperated solar gas-turbine power plant has been developed in order to allow determination of the thermodynamic and economic performance. The model was then used for multi-objective thermoeconomic optimization of both the power plant performance and cost, using a population-based algorithm. In order to examine the trade-offs that must be made and identify optimal' plant sizes and operating conditions, two conflicting objectives were considered, namely minimum investment costs and maximum annual electricity production. Levelized electricity costs from a 65 MWe power plant operating at 950°C are predicted to be below 130 USD/MWhe, competitive with other solar thermal power technologies. Optimal plant sizes and configurations have been identified.
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| 4. |
- Spelling, James, 1987-, et al.
(författare)
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Annual performance improvement for solar steam turbines through the use of temperature-maintaining modifications
- 2012
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 86:1, s. 496-504
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Tidskriftsartikel (refereegranskat)abstract
- Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. By maintaining higher internal temperature during idle periods, faster start-up times can be achieved, increasing the flexibility of the plant as well as increasing net electrical production. Prior work by the authors identified a number of methods for achieving this, with strong increases in daily production predicted; only two specific start-up cases were studied however. In order to obtain a more representative evaluation of the performance increase that can be achieved through increased dispatchability of the turbine, the annual improvement needs to be studied. Building on the existing results, a dynamic system model of a parabolic trough power plant has been established and used to determine the distribution of different cool-down times experienced throughout the year, with a view to evaluating the potential annual production increase. A modification of the start-up curves allows an increase in annual electrical production between 6.4% and 2.4% depending upon the operating mode (free operation versus day-time operation). Through application of a combination of heat blankets and an increase in gland steam temperature, further annual production increases between 2.2% and 3.1% are predicted.
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| 5. |
- Spelling, James, 1987-, et al.
(författare)
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Optimal Gas-Turbine Design for Hybrid Solar Power Plant Operation
- 2012
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Ingår i: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 134:9
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Tidskriftsartikel (refereegranskat)abstract
- A dynamic simulation model of a hybrid solar gas-turbine power plant has been developed, allowing determination of its thermodynamic and economic performance. In order to examine optimum gas-turbine designs for hybrid solar power plants, multi-objective thermoeconomic analysis has been performed, with two conflicting objectives: minimum levelized electricity costs and minimum specific CO2 emissions. Optimum cycle conditions: pressure-ratio, receiver temperature, turbine inlet temperature and flow rate, have been identified for a 15 MWe gas-turbine under different degrees of solarization. At moderate solar shares, the hybrid solar gas-turbine concept was shown to provide significant water and CO2 savings with only a minor increase in the levelized electricity cost.
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| 6. |
- Spelling, James, 1987-, et al.
(författare)
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The Value of Storage in Hybrid Solar Gas-Turbine Power Plants
- 2012
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Ingår i: Proceedings of the International SolarPACES Conference 2012, Marrakesh.
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Konferensbidrag (refereegranskat)abstract
- A thermoeconomic simulation model of a hybrid solar gas-turbine power plant with an integrated storage unit has been developed, allowing determination of the thermodynamic and economic performance. Designs were based around two representative industrial gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific CO2 emissions. It was shown that with the integration of storage, annual solar shares above 85% can be achieved by hybrid solar gas-turbine systems. The levelised electricity cost for the gas-turbine system as this level of solar integration was similar to that of parabolic trough plants, allowing them to compete directly in the solar power market. At the same time, the water consumption of the gas-turbine system is significantly lower than contemporary steam-cycle based solar thermal power plants.
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| 7. |
- Spelling, James, 1987-, et al.
(författare)
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Thermal modeling of a solar steam turbine with a focus on start-up time reduction
- 2012
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Ingår i: Proceedings of the ASME Turbo Expo 2011, Vol 3. - 9780791854631 ; , s. 1021-1030
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Konferensbidrag (refereegranskat)abstract
- Steam turbines in solar thermal power plants experience a much greater number of starts than those operating in base-load plants. In order to preserve the lifetime of the turbine whilst still allowing fast starts, it is of great interest to find ways to maintain the turbine temperature during idle periods. A dynamic model of a solar steam turbine has been elaborated, simulating both the heat conduction within the body and the heat exchange with the gland steam, main steam and the environment, allowing prediction of the temperatures within the turbine during off-design operation and standby. The model has been validated against 96h of measured data from the Andasol 1 power plant, giving an average error of 1.2% for key temperature measurements. The validated model was then used to evaluate a number of modifications that can be made to maintain the turbine temperature during idle periods. Heat blankets were shown to be the most effective measure for keeping the turbine casing warm, whereas increasing the gland steam temperature was most effective in maintaining the temperature of the rotor. By applying a combination of these measures the dispatchability of the turbine can be improved significantly: electrical output can be increased by up to 9.5% after a long cool-down and up to 9.8% after a short cool-down.
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| 8. |
- Spelling, James, 1987-, et al.
(författare)
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Thermoeconomic optimization of a combined-cycle solar tower power plant
- 2012
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 41:1, s. 113-120
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Tidskriftsartikel (refereegranskat)abstract
- A dynamic model of a pure-solar combined-cycle power plant has been developed in order to allow determination of the thermodynamic and economic performance of the plant for a variety of operating conditions and superstructure layouts. The model was then used for multi-objective thermoeconomic optimization of both the power plant performance and cost, using a population-based evolutionary algorithm. In order to examine the trade-offs that must be made, two conflicting objectives will be considered, namely minimal investment costs and minimal levelized electricity costs. It was shown that efficiencies in the region of 18-24% can be achieved, and this for levelized electricity costs in the region of 12-24 UScts/kWh(e), depending on the magnitude of the initial investment, making the system competitive with current solar thermal technology.
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| 9. |
- Strand, Torsten, et al.
(författare)
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An Innovative Hybrid Solar Gas-Turbine Power Plant based on the TopCycle Concept
- 2012
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Ingår i: Proceedings of the International SolarPACES Conference 2012, Marrakesh.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The TopCycle is an innovative gas-turbine power plant, in which a supercharger unit is added to a conventional industrial gas-turbine to boost the pressure ratio, and large amounts of steam are injected into the combustion chamber in order to achieve near- stoichiometric combustion. A thermoeconomic simulation model of a hybrid solar version of such a power plant has been developed, allowing determination of its thermodynamic and economic performance, and the results are compared with a more conventional hybrid solar combined cycle power plant. The analysis has shown that a hybrid solar TopCycle power plant can produce electricity with CO2 emissions below 300 kgCO2/MWhe at levelized costs around 60 – 80 €/MWhe, lower than the competing hybrid combined cycle units, and directly competitive with wind power.
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