Research progress on specific heat capacity improvement of molten salt nanofluids

doi:10.3969/j.issn.2097-0706.2024.12.006

Abstract

Abstract:

At present， as an efficient energy storage solution， molten salt heat storage technology has not only been widely used in the field of solar thermal power generation， but also in the flexibility modification of thermal power plants and other diversified scenarios. The heat storage performance of molten salt medium is one of the most critical factors that affect the progress of large-scale commercial application of molten salt heat storage systems. Doping nanoparticles into molten salt systems to prepare molten salt nanofluids is a highly promising method to enhance the heat storage performance of molten salt， significantly improving its thermal physical properties， such as specific heat capacity， thermal conductivity， and operating temperature. The application background of molten salt heat storage is introduced in detail， the latest mechanism for strengthening the thermal properties of molten salt is clarified， and the mechanism of improving thermal properties of molten salt nanofluids based on molecular dynamics simulation is summarized. In addition， a comprehensive review of recent advances in enhancing specific heat capacity of representative nanoparticle-doped molten salt is presented， and insights into future research directions and development trends are proposed.

Key words: molten salt heat storage, nanomaterials, specific heat capacity, molten salt nanofluid, molecular dynamics simulation

CLC Number:

TK02

LIU Heng, YU Yang, LI Minghang, LIANG Meng, YAN Ting, ZHAO Dazhou. Research progress on specific heat capacity improvement of molten salt nanofluids[J]. Integrated Intelligent Energy, 2024, 46(12): 45-54.

Figures/Tables 11

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References 58

[1]	薛福, 马晓明, 游焰军. 储能技术类型及其应用发展综述[J]. 综合智慧能源, 2023, 45(9): 48-58. doi: 10.3969/j.issn.2097-0706.2023.09.007
	XUE Fu, MA Xiaoming, YOU Yanjun. Energy storage technologies and their applications and development[J]. Integrated Intelligent Energy, 2023, 45(9): 48-58. doi: 10.3969/j.issn.2097-0706.2023.09.007
[2]	赵鑫, 钱本华, 王睿, 等. 电化学储能参与电网安全稳定控制的研究综述[J]. 综合智慧能源, 2023, 45(1):58-66. doi: 10.3969/j.issn.2097-0706.2023.01.007
	ZHAO Xin, QIAN Benhua, WANG Rui, et al. Review of researches on grid security and stability control with the participation of electrochemical energy storage[J]. Integrated Intelligent Energy, 2023, 45(1): 58-66. doi: 10.3969/j.issn.2097-0706.2023.01.007
[3]	何雅玲, 严俊杰, 杨卫卫, 等. 分布式能源系统中能量的高效存储[J]. 中国科学基金, 2020, 34(3): 272-280.
	HE Yaling, YAN Junjie, YANG Weiwei, et al. High efficient energy storage in distributed energy system[J]. Bulletin of National Natural Science Foundation of China, 2020, 34(3): 272-280.
[4]	ROPER R, HARKEMA M, SABHARWALL P, et al. Molten salt for advanced energy applications: A review[J]. Annals of Nuclear Energy, 2022, 169: 108924.
[5]	马汀山, 王妍, 吕凯, 等. “双碳” 目标下火电机组耦合储能的灵活性改造技术研究进展[J]. 中国电机工程学报, 2022, 42(S1): 136-148.
	MA Tingshan, WANG Yan, LYU Kai, et al. Research progress on flexibility transformation technology of coupled energy storage for thermal power units under the "dual-carbon" goal[J]. Proceedings of the CSEE, 2022, 42(S1): 136-148.
[6]	张钟平, 刘亨, 谢玉荣, 等. 熔盐储热技术的应用现状与研究进展[J]. 综合智慧能源, 2023, 45(9): 40-47. doi: 10.3969/j.issn.2097-0706.2023.09.006
	ZHANG Zhongping, LIU Heng, XIE Yurong, et al. Application and research progress of molten salt heat storage technology[J]. Integrated Intelligent Energy, 2023, 45(9): 40-47. doi: 10.3969/j.issn.2097-0706.2023.09.006
[7]	WANG B G, MA H, REN S J, et al. Effects of integration mode of the molten salt heat storage system and its hot storage temperature on the flexibility of a subcritical coal-fired power plant[J]. Journal of Energy Storage, 2023, 58: 106410.
[8]	HAN Y, ZHANG C C, WU Y T, et al. Investigation on thermal performance of quaternary nitrate-nitrite mixed salt and solar salt under thermal shock condition[J]. Renewable Energy, 2021, 175: 1041-1051.
[9]	左芳菲, 韩伟, 姚明宇. 熔盐储能在新型电力系统中应用现状与发展趋势[J]. 热力发电, 2023, 52(2): 1-9.
	ZUO Fangfei, HAN Wei, YAO Mingyu. Application status and development trend of molten salt energy storage in novel power systems[J]. Thermal Power Generation, 2023, 52(2): 1-9.
[10]	田禾青, 周俊杰, 郭茶秀. 熔盐储热材料比热容强化的研究进展[J]. 化工进展, 2020, 39(2): 584-595. doi: 10.16085/j.issn.1000-6613.2019-0798
	TIAN Heqing, ZHOU Junjie, GUO Chaxiu. Progress of specific heat enhancement of molten salt thermal energy storage materials[J]. Chemical Industry and Engineering Progress, 2020, 39(2): 584-595. doi: 10.16085/j.issn.1000-6613.2019-0798
[11]	熊亚选, 张慧, 吴玉庭, 等. 纳米颗粒对二元硝酸盐表面张力和密度的影响[J]. 储能科学与技术, 2021, 10(4): 1297-1304. doi: 10.19799/j.cnki.2095-4239.2021.0112
	XIONG Yaxuan, ZHANG Hui, WU Yuting, et al. Effect of nanoparticles on surface tension and density of binary nitrate[J]. Energy Storage Science and Technology, 2021, 10(4): 1297-1304. doi: 10.19799/j.cnki.2095-4239.2021.0112
[12]	ALI H M, REHMAN T U, ARICI M, et al. Advances in thermal energy storage:Fundamentals and applications[J]. Progress in Energy and Combustion Science, 2024, 100: 101109.
[13]	吴玉庭, 明苏布道, 张灿灿, 等. 三元混合碳酸熔盐热物性实验研究[J]. 储能科学与技术, 2021, 10(4): 1292-1296. doi: 10.19799/j.cnki.2095-4239.2021.0126
	WU Yuting, MING Subudao, ZHANG Cancan, et al. Experimental research of the thermophysical properties of ternary mixed carbonate molten salts[J]. Energy Storage Science and Technology, 2021, 10(4): 1292-1296. doi: 10.19799/j.cnki.2095-4239.2021.0126
[14]	WEI X L, YIN Y, QIN B, et al. Thermal conductivity improvement of liquid nitrate and darbonate salts doped with MgO particles[J]. Energy Procedia, 2017,142: 407-412.
[15]	张灿灿, 韩松涛, 吴玉庭, 等. 硝基熔盐纳米流体在扭曲扁管内流动与换热特性[J]. 储能科学与技术, 2022, 11(11): 3641-3648. doi: 10.19799/j.cnki.2095-4239.2022.0356
	ZHANG Cancan, HAN Songtao, WU Yuting, et al. Nitrate molten salt-based nanofluid flow and heat transfer characteristics in twisted tube[J]. Energy Storage Science and Technology, 2022, 11(11): 3641-3648. doi: 10.19799/j.cnki.2095-4239.2022.0356
[16]	UEKI Y, FUJITA N, KAWAI M, et al. Thermal conductivity of molten salt-based nanofluid[J]. AIP Advances, 2017, 7(5): 055117.
[17]	CHEN H Z, CHEN Z N, YANG H, et al. A study on quaternary mixed fluoride salts as heat storage materials[J]. Ceramics International, 2021, 47(22):32153-32159.
[18]	YE F, GE Z W, DING Y L, et al. Multi-walled carbon nanotubes added to Na₂CO₃/MgO composites for thermal energy storage[J]. Particuology, 2014, 15: 56-60.
[19]	魏小兰, 谢佩, 张雪钏, 等. 氯化物熔盐材料的制备及其热物理性质研究[J]. 化工学报, 2020, 71(5): 2423-2431. doi: 10.11949/0438-1157.20191541
	WEI Xiaolan, XIE Pei, ZHANG Xuechuan, et al. Research on preparation and thermodynamic properties of chloride molten salt materials[J]. CIESC Journal, 2020, 71(5): 2423-2431.
[20]	UEKI Y, FUJITA N, KAWAI M, et al. Molten salt thermal conductivity enhancement by mixing nanoparticles[J]. Fusion Engineering and Design, 2018, 136: 1295-1299.
[21]	熊亚选, 王慧慧, 宋超宇, 等. 纳米熔盐传热储热分布均匀性研究[J]. 中国科技论文, 2022, 17(7): 823-830.
	XIONG Yaxuan, WANG Huihui, SONG Chaoyu, et al. Homogeneity of heat transfer and thermal energy storage of molten salt nanofluids[J]. China Sciencepaper, 2022, 17(7): 823-830.
[22]	YADAV A, VERMA A, KUMAR A, et al. Recent advances on enhanced thermal conduction in phase change materials using carbon nanomaterials[J]. Journal of Energy Storage, 2021, 43: 103173.
[23]	WANG W, WU Z, LI B X, et al. A review on molten-salt-based and ionic-liquid-based nanofluids for medium-to-high temperature heat transfer[J]. Journal of Thermal Analysis and Calorimetry, 2019, 136(3): 1037-1051.
[24]	ONG T C, SARVGHAD M, LIPPIATT K, et al. Review of the solubility,monitoring, and purification of impurities in molten salts for energy storage in concentrated solar power plants[J]. Renewable and Sustainable Energy Reviews, 2020, 131: 110006.
[25]	冷光辉, 曹惠, 彭浩, 等. 储热材料研究现状及发展趋势[J]. 储能科学与技术, 2017, 6(5): 1058-1075.
	LENG Guanghui, CAO Hui, PENG Hao, et al. The new research progress of thermal energy storage materials[J]. Energy Storage Science and Technology, 2017, 6(5): 1058-1075. doi: 10.12028/j.issn.2095-4239.2017.00094
[26]	MOHAN G, VENKATARAMAN M B, COVENTRY J. Sensible energy storage options for concentrating solar power plants operating above 600 ℃[J]. Renewable and Sustainable Energy Reviews, 2019, 107: 319-337.
[27]	CHEN C L, TRAN T, OLIVARES R, et al. Coupled experimental study and thermodynamic modeling of melting point and thermal stability of Li₂CO₃-Na₂CO₃-K₂CO₃ based salts[J]. Journal of Solar Energy Engineering, 2014, 136(3): 031017.
[28]	SANG L X, CAI M, ZHAO Y B, et al. Mixed metal carbonates/hydroxides for concentrating solar power analyzed with DSC and XRD[J]. Solar Energy Materials and Solar Cells, 2015, 140: 167-173.
[29]	ALJAERANI H A, SAMYKANO M, SAIDUR R, et al. Nanoparticles as molten salts thermophysical properties enhancer for concentrated solar power: A critical review[J]. Journal of Energy Storage, 2021, 44: 103280.
[30]	宋文兵, 鹿院卫, 陈晓彤, 等. 氯化盐/陶瓷定形复合相变材料的制备和热物性研究[J]. 储能科学与技术, 2021, 10(5): 1720-1728. doi: 10.19799/j.cnki.2095-4239.2021.0319
	SONG Wenbing, LU Yuanwei, CHEN Xiaotong, et al. The preparation and thermophysical properties of chloride/ceramic-shaped stabilized composite phase-change materials[J]. Energy Storage Science and Technology, 2021, 10(5): 1720-1728. doi: 10.19799/j.cnki.2095-4239.2021.0319
[31]	MUÑOZ-SÁNCHEZ B, NIETO-MAESTRE J, IPARRAGUIRRE-TORRES I, et al. Molten salt-based nanofluids as efficient heat transfer and storage materials at high temperatures.An overview of the literature[J]. Renewable and Sustainable Energy Reviews, 2018,82: 3924-3945.
[32]	CHOI S U S, EASTMAN J A. Enhancing thermal conductivity of fluids with nanoparticles[J]. ASME Fed, 1995, 231: 99-105.
[33]	SHIN D, BANERJEE D. Enhanced specific heat of silica nanofluid[J]. Journal of Heat Transfer, 2011, 133(2): 024501.
[34]	HO M X, PAN C. Optimal concentration of alumina nanoparticles in molten Hitec salt to maximize its specific heat capacity[J]. International Journal of Heat and Mass Transfer, 2014, 70: 174-184.
[35]	吴玉庭, 张璐迪, 马重芳, 等. 纳米SiO₂在低熔点熔盐中的分散对其比热容的影响[J]. 北京工业大学学报, 2016, 42(8): 1259-1264.
	WU Yuting, ZHANG Ludi, MA Chongfang, et al. Effect of nanoparticles dispersion on enhancing the specific heat of the low melting point salt[J]. Journal of Beijing University of Technology, 2016, 42(8): 1259-1264.
[36]	SHIN D, BANERJEE D. Enhancement of specific heat capacity of high-temperature silica-nanofluids synthesized in alkali chloride salt eutectics for solar thermal-energy storage applications[J]. International Journal of Heat and Mass Transfer, 2011, 54(5/6): 1064-1070.
[37]	ZHANG Y, LI J L, GAO L, et al. Nitrate based nanocomposite thermal storage materials: Understanding the enhancement of thermophysical properties in thermal energy storage[J]. Solar Energy Materials and Solar Cells, 2020, 216: 110727.
[38]	SVOBODOVA-SEDLACKOVA A, BARRENECHE C, ALONSO G, et al. Effect of nanoparticles in molten salts-MD simulations and experimental study[J]. Renewable Energy, 2020, 152: 208-216.
[39]	SHIN D, TIZNOBAIK H, BANERJEE D. Specific heat mechanism of molten salt nanofluids[J]. Applied Physics Letters, 2014, 104:121914.
[40]	VAKA M, KHALID M, PAUL J. A review of different models, mechanisms, theories and parameters in tuning the specific heat capacity of nano-phase change materials[J]. Journal of Energy Storage, 2023, 72: 108678.
[41]	DU L C, DING J, WANG W L, et al. Molecular dynamics simulations on the binary eutectic system Na₂CO₃-K₂CO₃[J]. Energy Procedia, 2017, 142: 3553-3559.
[42]	YUAN F, LI M J, QIU Y, et al. Specific heat capacity improvement of molten salt for solar energy applications using charged single-walled carbon nanotubes[J]. Applied Energy, 2019, 250: 1481-1490.
[43]	LIU J J, XIAO X. Molecular dynamics investigation of thermo-physical properties of molten salt with nanoparticles for solar energy application[J]. Energy, 2023, 282: 128732.
[44]	HU Y W, HE Y R, ZHANG Z D, et al. Enhanced heat capacity of binary nitrate eutectic salt-silica nanofluid for solar energy storage[J]. Solar Energy Materials and Solar Cells, 2019, 192: 94-102.
[45]	CUI L, YU Q S, HUANG C, et al. Nanoadditives induced enhancement of thermal energy storage properties of molten salt: insights from experiments and molecular dynamics simulations[J]. Journal of Energy Storage, 2023, 72: 108612.
[46]	LIANG F, WEI X L, LU J F, et al. Interplay between interfacial layer and nanoparticle dispersion in molten salt nanofluid: collective effects on thermophysical property enhancement revealed by molecular dynamics simulations[J]. International Journal of Heat and Mass Transfer, 2022, 196: 123305.
[47]	SHIN D, BANERJEE D. Enhanced specific heat capacity of nanomaterials synthesized by dispersing silica nanoparticles in eutectic mixtures[J]. Journal of Heat Transfer, 2013, 135(3): 032801.
[48]	ABIR F M, SHIN D. Molecular dynamics study on the impact of the development of dendritic nanostructures on the specific heat capacity of molten salt nanofluids[J]. Journal of Energy Storage, 2023, 71: 107850.
[49]	JEONG S, JO B. Understanding mechanism of enhanced specific heat of single molten salt-based nanofluids: comparison with acid-modified salt[J]. Journal of Molecular Liquids, 2021, 336: 116561.
[50]	JEONG S, JO B. Distinct behaviors of KNO₃ and NaNO₃ in specific heat enhancement of molten salt nanofluid[J]. Journal of Energy Storage, 2023, 57: 106209.
[51]	HO M X, PAN C. Experimental investigation of heat transfer performance of molten HITEC salt flow with alumina nanoparticles[J]. International Journal of Heat and Mass Transfer, 2017, 107: 1094-1103.
[52]	KRISHNA Y, SAIDUR R, FAIZAL M, et al. Effect of Al₂O₃ dispersion on enthalpy and thermal stability of ternary nitrate eutectic salt[J]. International Journal of Nanoelectronics and Materials, 2020,13: 75-84.
[53]	NAYFEH Y, RIZVI S M M, EL FAR B, et al. In situ synthesis of alumina nanoparticles in a binary carbonate salt eutectic for enhancing heat capacity[J]. Nanomaterials, 2020, 10(11): 2131.
[54]	TAO Y B, LIN C H, HE Y L. Preparation and thermal properties characterization of carbonate salt/carbon nanomaterial composite phase change material[J]. Energy Conversion and Management, 2015, 97: 103-110.
[55]	KANG Z Y, XU J M, LIU H, et al. Thermophysical properties of LiF-LiCl-Li₂CO₃ eutectic mixture/multi-walled carbon nanotubes for thermal energy storage[J]. Solar Energy Materials and Solar Cells, 2022,241: 111744.
[56]	WEI X L, YIN Y, QIN B, et al. Preparation and enhanced thermal conductivity of molten salt nanofluids with nearly unaltered viscosity[J]. Renewable Energy, 2020, 145: 2435-2444.
[57]	MADATHIL P K, BALAGI N, SAHA P, et al. Preparation and characterization of molten salt based nanothermic fluids with enhanced thermal properties for solar thermal applications[J]. Applied Thermal Engineering, 2016, 109: 901-905.
[58]	LIU M, SEVERINO J, BRUNO F, et al. Experimental investigation of specific heat capacity improvement of a binary nitrate salt by addition of nanoparticles/microparticles[J]. Journal of Energy Storage, 2019, 22: 137-143.

熔盐成分	工作温度/℃	比热容/[J·(g·K)^-1]	热传导系数/[kW·(m·K)^-1]	密度/（kg·m^-3)
60%NaNO₃+40%KNO₃	220~565	1.50	0.52	1 753
53%KNO₃+40%NaNO₂+7%NaNO₃	142~535	1.40	0.35	1 723
15%NaNO₃+43%KNO₃+42%Ca(NO₃)₂	120~500	1.45	0.52	1 992
29%LiNO₃+18%NaNO₃+53%KNO₃	120~540	1.64		1 780
62%Li₂CO₃+38%K₂CO₃	400~900	1.60		1 967(577 ℃)
34.52%K₂CO₃+32.12%Li₂CO₃+33.36%Na₂CO₃	378~800	1.61	0.49	2 010(600 ℃)
68.6%ZnCl₂+7.5%NaCl+23.9%KCl	204~850	0.81(300~600 ℃)		2 000(600 ℃)
68.2%MgCl₂+14%NaCl+17.8%KCl	380~800	1.00(500~800 ℃)
29%LiF+12%NaF+59%KF	454~1 600	1.89	0.92	2 020
3.2%NaF+96.8%NaBF₄	3 845~700	1.51	0.63	1 750
32.5%KF+67.5%ZrF₄	390~1 450	1.04	0.32	2 800
4%NaF+27%KF+69%ZrF₄	385	1.09	0.36	2 920

基盐	纳米粒子	模拟软件	研究的热物性
Li₂CO₃-K₂CO₃	SWCNT	LAMMPS	比热容
太阳盐	SiO₂	LAMMPS	比热容+热导率
Li₂CO₃-Na₂CO₃-K₂CO₃	Al₂O₃，SiO₂， MWCNTs	LAMMPS	比热容
太阳盐	SiO₂	LAMMPS	比热容
Hitec	MgO	PACKMOL	比热容+热导率
Li₂CO₃-K₂CO₃	SiO₂	MedeA3.1+ LAMMPS	比热容