Effect of spectral-selectivity on the performance of thermochemical cycling driven by concentrated solar energy
LIN Pengzhu1,3, LOU Jiahui1,2, LI Jianlan3, HAO Yong1,2
1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
Abstract：Splitting H2O or CO2 via solar-driven thermochemical redox cycles is important for solar fuel production. Since the reactor chamber temperature in thermochemical redox cycles is much lower than the surface temperature of the sun, secondary radiation from the reactor chamber to the ambient can be suppressed by spectral-selective transmissive coatings. These significantly reduce the irreversible losses, improve the solar thermal collection efficiency, and reduce the solar thermal collection cost. The cutoff wavelength is a key characteristic parameter of spectral-selective transmissive coatings which significantly affect the thermochemical performance of solar-driven thermochemical cycling. This study investigates the effect of the spectral-selective transmissive coatings on the solar-to-fuel efficiency based on experimental data for thermochemical splitting of CO2 using reticulated porous ceria. This work also discusses the economic impact of the spectral-selective transmissive coatings on the solar thermal collector cost. The results show that for a solar-driven thermochemical redox cycle with a high temperature of 1 773 K, the optimal cutoff wavelength is 1 350 nm, which coincides with the steam and CO2 absorption peaks in the solar spectrum (AM1.5). Spectral-selective transmissive coatings can increase the theoretical solar thermal collection efficiency of a blackbody cavity by 34.7%~85.2% and can significantly enhance the upper limit of the solar-to-fuel energy efficiency. The coatings can reduce the reduction half-reaction heating time by 13.7% and radiation losses by 36.7%. Finally, this work analyzes the economic impact of the spectral-selective transmissive coating on the solar thermal collector cost. The spectral-selective transmissive coatings can effectively reduce the solar thermal collector cost when the unit cost of the spectral-selective transmissive coatings is 330 times less than the cost of a dish concentrator.
林鹏翥, 娄佳慧, 李建兰, 郝勇. 光谱选择透过性对聚光太阳能热化学循环性能的影响[J]. 清华大学学报（自然科学版）, 2021, 61(12): 1389-1396.
LIN Pengzhu, LOU Jiahui, LI Jianlan, HAO Yong. Effect of spectral-selectivity on the performance of thermochemical cycling driven by concentrated solar energy. Journal of Tsinghua University(Science and Technology), 2021, 61(12): 1389-1396.
[1] LEWIS N S. Research opportunities to advance solar energy utilization[J]. Science, 2016, 351(6271):aad1920. [2] ROMERO M, STEINFELD A. Concentrating solar thermal power and thermochemical fuels[J]. Energy & Environmental Science, 2012, 5(11):9234-9245. [3] SHIH C F, ZHANG T, LI J H, et al. Powering the future with liquid sunshine[J]. Joule, 2018, 2(10):1925-1949. [4] STEINFELD A. Solar thermochemical production of hydrogen-A review[J]. Solar Energy, 2005, 78(5):603-615. [5] RAO C N R, DEY S. Solar thermochemical splitting of water to generate hydrogen[J]. Proceedings of the National Academy of Sciences, 2017, 114(51):13385-13393. [6] HAO Y, STEINFELD A. Fuels from water, CO2 and solar energy[J]. Science Bulletin, 2017, 62(16):1099-1101. [7] CHUEH W C, FALTER C, ABBOTT M, et al. High-flux solar-driven thermochemical dissociation of CO2 and H2O using nonstoichiometric ceria[J]. Science, 2010, 330(6012):1797-1801. [8] FURLER P, SCHEFFE J R, STEINFELD A. Syngas production by simultaneous splitting of H2O and CO2 via ceria redox reactions in a high-temperature solar reactor[J]. Energy & Environmental Science, 2012, 5(3):6098-6103. [9] FURLER P, SCHEFFE J, MARXER D, et al. Thermochemical CO2 splitting via redox cycling of ceria reticulated foam structures with dual-scale porosities[J]. Physical Chemistry Chemical Physics, 2014, 16(22):10503-10511. [10] MARXER D, FURLER P, TAKACS M, et al. Solar thermochemical splitting of CO2 into separate streams of CO and O2 with high selectivity, stability, conversion, and efficiency[J]. Energy & Environmental Science, 2017, 10(5):1142-1149. [11] FURLER P, STEINFELD A. Heat transfer and fluid flow analysis of a 4 kW solar thermochemical reactor for ceria redox cycling[J]. Chemical Engineering Science, 2015, 137:373-383. [12] ZANGANEH G, PEDRETTI A, ZAVATTONI S, et al. Packed-bed thermal storage for concentrated solar power-Pilot-scale demonstration and industrial-scale design[J]. Solar Energy, 2012, 86(10):3084-3098. [13] GAO Y, WANG Z M, DING D, et al. Novel methods to harness solar radiation for advanced energy applications[J]. ES Energy & Environment, 2019, 5:1-7. [14] CHOPRA K L, REDDY G B. Optically selective coatings[J]. Pramana, 1986, 27(1-2):193-217. [15] JANICKI V, GÄBLER D, WILBRANDT S, et al. Deposition and spectral performance of an inhomogeneous broadband wide-angular antireflective coating[J]. Applied Optics, 2006, 45(30):7851-7857. [16] HU P, LIU Y, ZHANG Q, et al. Thermodynamic analysis on medium-high temperature solar thermal systems with selective coatings[J]. Science China Technological Sciences, 2013, 56(12):3137-3143. [17] JIN J, WEI X, LIU M K, et al. A solar methane reforming reactor design with enhanced efficiency[J]. Applied Energy, 2018, 226:797-807. [18] RÖGER M, RICKERS C, UHLIG R, et al. Infrared-reflective coating on fused silica for a solar high-temperature receiver[J]. Journal of Solar Energy Engineering, 2009, 131(2):021004. [19] 金健. 聚光太阳能燃料转化机理研究[D]. 北京:中国科学院大学(中国科学院工程热物理研究所), 2019. JIN J. Study on concentrated solar-driven thermochemical fuel production[D]. Beijing:University of Chinese Academy of Sciences, Institute of Engineering Thermophysics, Chinese Academy of Sciences, 2019. (in Chinese) [20] GIOSTRI A, MACCHI E. An advanced solution to boost sun-to-electricity efficiency of parabolic dish[J]. Solar Energy, 2016, 139:337-354.
2021, Vol. 61 
