| 1. |
- Guccione, Salvatore, et al.
(författare)
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Optimum Coupling of Thermal Energy Storage and Power Cycles
- 2023
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Ingår i: Proceedings of ASME Turbo Expo 2023. - : American Society of Mechanical Engineers (ASME).
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Konferensbidrag (refereegranskat)abstract
- The present work proposes a methodology that enables decision-making in selecting the adequate power cycle and Thermal Energy Storage (TES) type for a wide range of operating temperatures between 380 and 1200 °C. A broad spectrum of power block configurations has been explored including steam Rankine, gas turbine, supercritical CO2, (sCO2) combined gas turbine with Rankine, and combined gas turbine with sCO2. The study also evaluated molten salt, particle, and air packed bed TES to identify the most cost-effective power cycle and TES combination. A techno-economic optimization has been conducted aimed at minimizing the Levelized Cost of Storage (LCOS) for different plant capacities and charging costs. Results show that coupling of a sCO2 power block with recompression and intercooling with a particle TES is the most cost-effective solution for a 100 MWe plant with 12 hours of storage and a charging cost of 50 EUR/MWh. This achieved an LCOS value of 154.7 EUR/MWh at 750 °C with a 200 °C temperature difference. Particle-based energy storage is the most cost-effective option for a wide range of temperature combinations, while an intercooled sCO2 power block with an air-packed bed TES should be preferred when electricity is free, and storage represents a significant portion of the capital cost. Molten salt TES is the optimal choice provided that the design temperatures align with the limitations of the salts.
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| 2. |
- Guccione, Salvatore, et al.
(författare)
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Techno-economic optimisation of a sodium-chloride salt heat exchanger for concentrating solar power applications
- 2022
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 239, s. 252-267
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Tidskriftsartikel (refereegranskat)abstract
- To enhance the economic viability of Concentrating solar power (CSP) plant, recent efforts have been directed towards employing high-temperature working fluid in the receiver and incorporating higher-efficiency power cycles. This work presents a techno-economic analysis of a sodium-chloride salt heat exchanger included in a sodium-driven CSP system with a supercritical CO2 power block. A quasi-steady state heat exchanger model was developed based on the TEMA guidelines, with the possibility of being customised in terms of media adopted, constraints, boundary conditions, and heat transfer correlations. The sodium-salt heat exchanger has been designed aiming at minimising the Levelized Cost of Electricity (LCOE) of the plant. The performance and the design of the proposed heat exchanger have been evaluated via multi-objective optimisation and sensitivity analyses. Results show that advanced CSP systems employing sodium and an indirect chloride salt storage can represent an economically viable solution and can drive towards the future goal of 5 USD/MWh. For a base-case 100 MWe plant with 12 h of storage, a LCOE of 72.7 USD/MWh and a capacity factor (CF) higher than 60% were reached. The techno-economic investigations showed the potential LCOE reduction of 6% as well as the flexibility and robustness of the heat exchanger model. The developed tool lays the groundwork to explore potential improvements of this new generation of CSP systems.
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| 3. |
- Guccione, Salvatore, et al.
(författare)
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Techno-Economic Optimization of a Hybrid PV-CSP Plant With Molten Salt Thermal Energy Storage and Supercritical CO2 Brayton Power Cycle
- 2022
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME International.
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Konferensbidrag (refereegranskat)abstract
- High-efficient supercritical CO2 (sCO2) power blocks and the hybridization with solar photovoltaic (PV) plants have been identified as two viable solutions to enhance the economic competitiveness of Concentrating Solar Power (CSP) plants. This work introduces an innovative hybrid PV-CSP system layout with molten salt thermal energy storage and a sCO2 power block. An active hybridization has been proposed employing a molten salt electric heater that allows storing the excess PV production as thermal energy. The scalability of the plant has been investigated using size-dependent cost functions and introducing a novel methodology for scaling the sCO2 turbomachinery efficiencies. The conducted techno-economic optimizations show that the proposed hybrid PV-CSP plants can be cost-competitive. For a European solar resource location - 1900 kWh/(m2yr) - Levelized Cost of Electricity (LCOE) values lower than 66 EUR/MWh and capacity factors higher than 70 % can be achieved at 100 MWe. For a high-irradiance location - 3400 kWh/(m2yr) - a capacity factor of 85 % and a LCOE of 46 EUR/MWh have been found for the same scale. The selection of the sCO2 power cycle has a marginal impact on these results so that a simple recuperated cycle can yield similar LCOEs as the recompressed, reheated, and intercooled layouts. For smaller scales, systems with large gaps between the PV and CSP capacities are preferred, laying the optimal conditions for the electric heater integration with utilization factors up to 21 %.
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| 4. |
- Guccione, Salvatore, et al.
(författare)
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Techno-economic optimization of molten salt based CSP plants through integration of supercritical CO2 cycles and hybridization with PV and electric heaters
- 2023
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 283
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Tidskriftsartikel (refereegranskat)abstract
- The present study explores the integration of supercritical CO2 (sCO2) power cycles into Concentrating Solar Power (CSP) plants using molten salt, and the hybridization of these plants with solar photovoltaic (PV) systems through electric heaters. Techno-economic evaluations determined the optimal power cycle configuration and subsystem designs for two different scales and locations and then compared them with state-of-the-art solar power plants. The results show that hybridizing PV with state-of-the-art CSP can lead up to a 22% reduction in the Levelized Cost of Electricity (LCOE) compared to standalone CSP systems. This hybridization and the use of electric heaters are particularly beneficial for small-scale installations and locations with low DNI/GHI ratios. By replacing the steam Rankine cycle with a sCO2 power block, a further 42% reduction in LCOE can be achieved at small scales, even with a simple recuperated cycle. In conclusion, the hybridization with PV and the integration of sCO2 power blocks provide cost benefits despite the temperature limitations imposed by the molten salt. Hybrid PV-CSP plants with sCO2 power blocks prove to be a cost-effective solution for capacity factors exceeding 60%. For lower capacity factors, configurations combining PV with battery energy storage or PV with electric heaters, thermal energy storage, and sCO2 power blocks are preferable options.
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| 5. |
- Guccione, Salvatore, et al.
(författare)
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Thermodynamic Analysis of a Hybrid PV-Particle Based sCO2 Concentrating Solar Power Plant
- 2023
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Ingår i: AIP Conference Proceedings. - : AIP Publishing.
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Konferensbidrag (refereegranskat)abstract
- The present work performs a thermodynamic analysis of a hybrid CSP – PV plant characterized by a particle tower CSP running a supercritical CO2 power unit and a PV field. The two plants are hybridized by employing a particle electrical heater that allows to store the electricity produced in excess by the PV field as thermal energy in the CSP storage. The PV production is compensated by the CSP plant to achieve the maximum power that can be injected into the grid (25 MW). The main key performance indicators considered in this analysis are the capacity factor, the share of energy wasted, the annual energy yield, the electric heater utilization factor, and the share of TES charged by the electric heater. The influence of the plant solar multiple, storage size, PV nominal size, electric heater efficiency, and electric heater capacity has been assessed through different sensitivity analyses. The results show that it is worth hybridizing the system, indeed the solar power plant operates during summer continuously day and night, exploiting the advantages of the two technologies, while limiting their drawbacks. Plant configurations leading to a capacity factor higher than 81% with a share of energy wasted limited to 5% can be identified. The electric heater capacity and efficiency are shown to be highly important parameters, highlighting the need for further component development.
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| 6. |
- Zheng, M., et al.
(författare)
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Exergy analysis of the impact of a heat exchanger on performance of an integrated sodium-salt CSP plant
- 2022
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Ingår i: SOLARPACES 2020. - : AIP Publishing.
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Konferensbidrag (refereegranskat)abstract
- High-temperature receivers are critical for third-generation (Gen3) Concentrating Solar Power (CSP) technology to achieve high system efficiencies, and play the role of converting concentrated sunlight into heat. In this paper, two CSP systems with different working fluids in the receiver are examined in order to achieve identical supply of heat to the power block: a direct high-temperature chloride salt system and an indirect high-temperature sodium receiver with an associated heat exchanger to heat the same chloride salt. The presented numerical model indicates that the indirect sodium-salt system has a 4.37% higher exergy efficiency than the direct chloride salt system. The exergy destruction in the added sodium-salt heat exchanger was only 0.54%, which did not outweigh the performance benefits gained from using a sodium receiver, when compared to the direct salt case with no heat exchanger. Even at lower DNIs, the better heat-transfer characteristics of the sodium are responsible for its improved performance compared to salt in the receivers.
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