| 1. |
- Gini, L., et al.
(författare)
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Part-Load Behaviour And Control Philosophy Of A Recuperated Supercritical Co2Cycle
- 2022
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Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME).
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Konferensbidrag (refereegranskat)abstract
- High efficiency, flexibility and competitive capital costs make supercritical CO2 (sCO2) systems a promising technology for renewable power generation in a low carbon energy scenario. Recently, innovative supercritical systems have been studied in the literature and proposed by DOE-NETL (STEP project) and a few projects in the EU Horizon 2020 program aiming to demonstrate supercritical CO2 Brayton power plants, promising superior techno-economic features than steam cycles particularly at high temperatures. The H2020 SOLARSCO2OL project1, which started in 2020, is building the first European MW-scale sCO2 demonstration plant and has been specifically tailored for Concentrating Solar Power (CSP) applications. This paper presents the first offdesign analysis of such a demonstrator, which is based on a simply recuperated sCO2 cycle. The part-load analysis ranged from 50% of nominal up to a 105% peak load, discussing the impact on compressor and turbine operating conditions. The whole system dynamic model has been developed in TRANSEO MATLAB® environment. Full operational envelop has been determined considering cycle main constraints, such as maximum turbine inlet temperature and minimum pressure at compressor inlet. The off-design performance analysis highlights the most relevant relationships among the main part-load regulating parameters, namely mass flow rate, total mass in the loop, and available heat source. The results show specific features of different control approaches, discussing the pros and cons of each solution, considering also its upscale towards commercial applications. In particular, the analysis shows that at 51% of load an efficiency decrease of 20% is expected.
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| 2. |
- Guédez, Rafael, et al.
(författare)
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Design Of A 2 Mw Molten Salt Driven Supercritical Co2 Cycle And Turbomachinery For The Solarsco2Ol Demonstration Project
- 2022
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Ingår i: Proceedings of the ASME Turbo Expo. - : ASME International.
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Konferensbidrag (refereegranskat)abstract
- Supercritical CO2 (sCO2) power cycles have been identified as technology enablers for increasing the cost-competitiveness of Concentrating Solar Power (CSP) plants. Compared to steam cycles, sCO2 cycles have the advantage of allowing higher inlet turbine temperatures, while also deploying turbomachinery that can be a ten-fold more compact. Ongoing research in CSP focuses mainly in developing new receiver and storage concepts able to withstand such required higher temperatures, alongside new heat exchangers that enable coupling to a sCO2 cycle. Meanwhile, advancements in sCO2 turbomachinery have taken place in research projects aimed at investigating the technical feasibility of the cycle, including the optimized design of its individual components and new cycle configurations. Among these, only few focus in demonstrating a full-integrated system, including cycle control and dynamics, and only two worldwide have started plans for MW-scale pilots, none of them in Europe. The EU-funded SOLARSCO2OL project aims at demonstrating a first-of-a-k ind 2 MW gross simple-recuperated sCO2 Brayton cycle driven by heat provided by molten salt s similar to those deployed in commercial CSP plants, which are able to operate at temperatures of up to 580°C. This paper introduces the project objectives and implementation plan, to then focus primarily on the results derived from the first year in specific relation to the conceptual design of each of 2 MW scale power cycle and its k ey components, including also the proposed integration and operational regimes, expected thermod ynamic performance at nominal point, and up-scaling considerations.
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| 3. |
- Sillrén, Per, 1982, et al.
(författare)
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Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy
- 2014
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 1089-7690 .- 0021-9606. ; 140:12
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Tidskriftsartikel (refereegranskat)abstract
- Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rössler, and R. Böhmer, Phys. Rev. Lett.105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.
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| 4. |
- 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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