Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle
The latest generation of concentrated solar power (CSP) systems uses supercritical carbon dioxide (s-CO<sub>2</sub>) as the working fluid in a high-performance recompression Brayton cycle (RcBC), whose off-design performance under different environmental conditions has yet to be fully ex...
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MDPI AG
2023-06-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/16/12/4755 |
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| author | Felipe G. Battisti Carlos F. Klein Rodrigo A. Escobar José M. Cardemil |
| author_facet | Felipe G. Battisti Carlos F. Klein Rodrigo A. Escobar José M. Cardemil |
| author_sort | Felipe G. Battisti |
| collection | DOAJ |
| description | The latest generation of concentrated solar power (CSP) systems uses supercritical carbon dioxide (s-CO<sub>2</sub>) as the working fluid in a high-performance recompression Brayton cycle (RcBC), whose off-design performance under different environmental conditions has yet to be fully explored. This study presents a model developed using the Engineering Equation Solver (EES) and System Advisor Model (SAM) to evaluate the operation of two solar-driven s-CO<sub>2</sub> RcBCs over a year, considering meteorological conditions in northern Chile. Under design conditions, the power plant outputs a net power of 25 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">M</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">W</mi></semantics></math></inline-formula> with a first-law efficiency of 48.3%. An exergy analysis reveals that the high-temperature recuperator contributes the most to the exergy destruction under nominal conditions. However, the yearly simulation shows that the gas cooler’s exergy destruction increases at high ambient temperatures, as does the turbine’s during off-design operation. The proposed cycle widens the operational range, offering a higher flexibility and synergistic turndown strategy by throttling the mass flow. The proposed cycle’s seasonal first-law efficiency of 39% outweighs the literature cycle’s 29%. When coupled to a thermal energy storage system, the proposed cycle’s capacity factor could reach 93.45%, compared to the value 76.45% reported for the cycle configuration taken from the literature. |
| first_indexed | 2024-03-11T02:30:47Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-11T02:30:47Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-6b7f0f17c6ac4e2b8fc3d6ef7689c0522023-11-18T10:13:41ZengMDPI AGEnergies1996-10732023-06-011612475510.3390/en16124755Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton CycleFelipe G. Battisti0Carlos F. Klein1Rodrigo A. Escobar2José M. Cardemil3Department of Mechanical and Metallurgical Engineering, Pontifical Catholic University of Chile, Santiago 7820436, ChileDepartment of Mechanical Engineering, Universidad de Chile, Santiago 8370456, ChileDepartment of Mechanical and Metallurgical Engineering, Pontifical Catholic University of Chile, Santiago 7820436, ChileDepartment of Mechanical and Metallurgical Engineering, Pontifical Catholic University of Chile, Santiago 7820436, ChileThe latest generation of concentrated solar power (CSP) systems uses supercritical carbon dioxide (s-CO<sub>2</sub>) as the working fluid in a high-performance recompression Brayton cycle (RcBC), whose off-design performance under different environmental conditions has yet to be fully explored. This study presents a model developed using the Engineering Equation Solver (EES) and System Advisor Model (SAM) to evaluate the operation of two solar-driven s-CO<sub>2</sub> RcBCs over a year, considering meteorological conditions in northern Chile. Under design conditions, the power plant outputs a net power of 25 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">M</mi></semantics></math></inline-formula><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="normal">W</mi></semantics></math></inline-formula> with a first-law efficiency of 48.3%. An exergy analysis reveals that the high-temperature recuperator contributes the most to the exergy destruction under nominal conditions. However, the yearly simulation shows that the gas cooler’s exergy destruction increases at high ambient temperatures, as does the turbine’s during off-design operation. The proposed cycle widens the operational range, offering a higher flexibility and synergistic turndown strategy by throttling the mass flow. The proposed cycle’s seasonal first-law efficiency of 39% outweighs the literature cycle’s 29%. When coupled to a thermal energy storage system, the proposed cycle’s capacity factor could reach 93.45%, compared to the value 76.45% reported for the cycle configuration taken from the literature.https://www.mdpi.com/1996-1073/16/12/4755solar-driven recompression Brayton cyclepart-loadsupercritical CO<sub>2</sub>exergy analysis |
| spellingShingle | Felipe G. Battisti Carlos F. Klein Rodrigo A. Escobar José M. Cardemil Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle Energies solar-driven recompression Brayton cycle part-load supercritical CO<sub>2</sub> exergy analysis |
| title | Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle |
| title_full | Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle |
| title_fullStr | Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle |
| title_full_unstemmed | Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle |
| title_short | Exergy Analysis and Off-Design Modeling of a Solar-Driven Supercritical CO<sub>2</sub> Recompression Brayton Cycle |
| title_sort | exergy analysis and off design modeling of a solar driven supercritical co sub 2 sub recompression brayton cycle |
| topic | solar-driven recompression Brayton cycle part-load supercritical CO<sub>2</sub> exergy analysis |
| url | https://www.mdpi.com/1996-1073/16/12/4755 |
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