In order to efficiently convert the concentrated heat of solar power tower system, three mixtures （CO2/R290, CO2/R600a and CO2/R601a） are applied to the recompression power cycle. An integrated model is established for the solar power tower system, and the corresponding thermal performances are analyzed and compared under the irradiation conditions of typical days in four seasons（March 20, June 21, September 23 and December 21）. The obtained results show that： in the mass fraction range of CO2-based mixture with nonflammability, as the CO2 mass fraction increases, the system thermal efficiency, exergy efficiency and generated power of the mixtures increase first and then decrease. The optimal mass fractions are 0.7/0.3, 0.8/0.2 and 0.8/0.2, respectively. Among these three mixtures, CO2/R290 （0.7/0.3） has the best performances with the thermal efficiency 18.99% and generated power 17.1 MWh at Vernal Equinox. Under different typical days, the thermal efficiency and exergy efficiency of Summer Solstice are slightly lower than those of Winter Solstice, but the generated power is the highest. Furthermore, based on the three CO2-based mixtures, effects of turbine inlet temperature, minimum cycle temperature, hot molten salt temperature and split ratio on system performances are also investigated. It’s found that there exists an optimal split ratio to achieve the highest thermal efficiency and generated power. For the recompression power system, the optimal split ratio is in the range of 0.70-0.75.
Key words
solar power tower system /
CO2 -based mixture /
recompression power cycle /
thermal performance
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References
[1] YU A F, SU W, LIN X X, et al.Recent trends of supercritical CO2 Brayton cycle: bibliometric analysis and research review[J]. Nuclear engineering and technology, 2021, 53(3): 699-714.
[2] LIU J H, YU A F, LIN X X, et al.Performances of transcritical power cycles with CO2-based mixtures for the waste heat recovery of ICE[J]. Entropy, 2021, 23(11): 1551.
[3] MANZOLINI G, BINOTTI M, BONALUMI D, et al.CO2 mixtures as innovative working fluid in power cycles applied to solar plants. techno-economic assessment[J]. Solar energy, 2019, 181: 530-544.
[4] YANG Y Y, XUE T C, RAO Z H, et al.Potential of transcritical recompression Rankine cycle operating with CO2-based binary mixtures[J]. Energy conversion and management, 2022, 252: 115040.
[5] 许芬. 塔式太阳能定日镜聚光成像建模及仿真[J]. 太阳能学报, 2010, 31(10): 1304-1310.
XU F.Modeling and simulation of sun image formed by CSP heliostat[J]. Acta energiae solaris sinica, 2010, 31(10): 1304-1310.
[6] COLLADO F J, GUALLAR J.A review of optimized design layouts for solar power tower plants with campo code[J]. Renewable and sustainable energy reviews, 2013, 20: 142-154.
[7] 付鹏, 王志峰, 余强, 等. 塔式太阳能热发电站热力性能综合评价[J]. 太阳能学报, 2021, 42(11): 86-97.
FU P, WANG Z F, YU Q, et al.Comprehensive thermal performance evaluation of tower solar power generation station[J]. Acta energiae solaris sinica, 2021, 42(11): 86-97.
[8] 陈建生. 太阳能-sCO2循环发电系统集成及热—经济—环境分析与优化[D]. 广州: 广东工业大学, 2021.
CHEN J S.SPT-sCO2 cycle power generation system thermal-economy-environment analysis and optimization[D]. Guangzhou: Guangdong University of Technology, 2021.
[9] WANG K, HE Y L.Thermodynamic analysis and optimization of a molten salt solar power tower integrated with a recompression supercritical CO2 Brayton cycle based on integrated modeling[J]. Energy conversion and management, 2017, 135: 336-350.
[10] 李兴, 王志峰, 杨铭, 等. 塔式太阳能热电联供系统性能研究[J]. 太阳能学报, 2021, 42(6): 203-210.
LI X, WANG Z F, YANG M, et al.Performance study of cogeneration system based on solar power tower plant[J]. Acta energiae solaris sinica, 2021, 42(6): 203-210.
[11] YU Q, WANG Z F, XU E S, et al.Modeling and dynamic simulation of the collector and receiver system of 1 MWe DAHAN solar thermal power tower plant[J]. Renewable energy, 2012, 43: 18-29.
[12] 王坤, 何雅玲, 邱羽, 等. 塔式太阳能熔盐腔体吸热器一体化光热耦合模拟研究[J]. 科学通报, 2016, 61(15): 1640-1649.
WANG K, HE Y L, QIU Y, et al.Integrated numerical study on the coupled photon-thermal conversion process in the central solar molten salt cavity receiver[J]. Chinese science bulletin, 2016, 61(15): 1640-1649.
[13] SIDDIQUI M E, ALMITANI K H.Energy and exergy assessment of S-CO2 Brayton cycle coupled with a solar tower system[J]. Processes, 2020, 8(10): 1264.
[14] ZABETAKIS M G.Flammability characteristics of combustible gases and vapors[M]. Bureau of Mines: Washington, DC, USA, 1965.
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