Study on Heat Storage Performance of Various Mixture Combinations of Stones, Sand, and Thermal Oil

doi:10.12096/j.2096-4528.pgt.24055

Abstract

Abstract:

Objectives Traditional concrete thermal energy storage systems are prone to cracking during cyclic heat storage processes, leading to a sharp decline in overall heat storage capacity and power, which severely affects system lifespan and increases heat storage costs. To mitigate these issues, a multi-component mixed heat storage method incorporating stones, sand, and thermal oil is proposed. Methods Utilizing computational fluid dynamics (CFD) simulation technology, the heat storage processes of different heat storage media are simulated and investigated. Results Cracked concrete experiences a 23.1% reduction in heat storage capacity compared to uncracked concrete. Under the same heat storage conditions, coarse sand demonstrates better heat storage performance than fine sand. The mixture of coarse sand and thermal oil exhibits a 7.2% higher heat storage capacity than that of cracked concrete. Furthermore, the mixture of sand, stones, and thermal oil increases heat storage capacity by 20.5% relative to cracked concrete used as heat storage medium. The released heat is slightly lower than the stored heat. The heat released by cracked concrete is 21.7% lower than that of uncracked concrete and 18.86% lower than that of the mixture of sand, stones, and thermal oil used as the heat storage medium. Cost calculations further reveal that the thermal energy storage system using the mixture of stones, sand, and thermal oil as the storage medium achieves higher heat storage capacity while resulting in lower fixed and maintenance costs. Conclusions This multi-component mixed heat storage method can effectively address concrete cracking issues, enhance heat storage efficiency, and reduce costs, which is of great significance for advancing the development and application of heat storage technologies.

Key words: energy storage, packed bed, thermal energy storage technology, heat storage medium, multi-component mixing, computational fluid dynamics, heat storage capacity, fixed cost

CLC Number:

TK 02

Lingxu LI, Longxiang CHEN, Kai YE. Study on Heat Storage Performance of Various Mixture Combinations of Stones, Sand, and Thermal Oil[J]. Power Generation Technology, 2025, 46(6): 1192-1199.

Figures/Tables 13

Fig. 1 Horizontal indirect heat transfer packed bed

Tab. 1 Packed bed model and material parameters

参数	数值
长( $L$ )/m	1
截面积( $W × H$ )/m²	0.12×0.12
管道直径/m	0.016
管道厚度/m	0.002
管道材料密度/(kg⋅m^-3)	8 030
管道材料比热容/(J⋅kg^-1⋅K^-1)	502.48
管道材料导热系数/(W⋅kg^-1⋅K^-1)	16.27
传热流体密度/(kg⋅m^-3)	868.50
传热流体比热容/(J⋅kg^-1⋅K^-1)	2 540
传热流体导热系数/(W⋅kg^-1⋅K^-1)	0.15

Tab. 1 Packed bed model and material parameters

参数	数值
长( $L$ )/m	1
截面积( $W × H$ )/m²	0.12×0.12
管道直径/m	0.016
管道厚度/m	0.002
管道材料密度/(kg⋅m^-3)	8 030
管道材料比热容/(J⋅kg^-1⋅K^-1)	502.48
管道材料导热系数/(W⋅kg^-1⋅K^-1)	16.27
传热流体密度/(kg⋅m^-3)	868.50
传热流体比热容/(J⋅kg^-1⋅K^-1)	2 540
传热流体导热系数/(W⋅kg^-1⋅K^-1)	0.15

Tab. 2 Heat storage material parameters

材料	密度ρ/(kg⋅m^-3)	比热容C_p /(J⋅kg^-1⋅K^-1)	导热系数λ/(W⋅kg^-1⋅K^-1)
混凝土	2 300	2 200	1.67
沙子	1 000	900	1.33
石块	2 359	1 100	3.50
开裂混凝土	1 955	900	1.34

Fig. 2 Mesh generation

Fig. 3 3D schematic diagram of validation model

Fig. 4 2D schematic diagram of validation model

Fig. 5 Validation of simulation results

Fig. 6 Variation of heat storage temperature between uncracked concrete and cracked concrete

Tab. 3 Comparison of heat storage performance between cracked concrete and uncracked concrete

储热介质	储热量/kJ	储热功率/kW
未开裂混凝土	3 117.59	1.25
开裂混凝土	2 397.99	0.96

Fig. 7 Comparison of heat storage performance of sand, stone, and concrete

Fig. 8 Comparison of heat storage performance of sand, stone, and thermal oil after mixing

Fig. 9 Heat storage and release capacity for different heat storage media

Fig.10 Comparison of fixed cost and heat storage performance of packed beds with different types of heat storage media

References 20

[1]	张丽娟，保富．含分布式新能源的多虚拟电厂协同运行[J]．电测与仪表，2025，62(9)：134-141．
	ZHANG L J， BAO F ．Coordinated operation of multiple virtual power plants integrated with distributed renewable energy[J]．Electrical Measurement & Instrumentation，2025，62(9)：134-141．
[2]	王放放，杨鹏威，赵光金，等．新型电力系统下火电机组灵活性运行技术发展及挑战[J]．发电技术，2024，45(2)：189-198．
	WANG F F， YANG P W， ZHAO G J，et al ．Development and challenge of flexible operation technology of thermal power units under new power system[J]．Power Generation Technology，2024，45(2)：189-198．
[3]	LIU M， WANG S， YAN J J ．Operation scheduling of a coal-fired CHP station integrated with power-to-heat devices with detail CHP unit models by particle swarm optimization algorithm[J]．Energy，2021，214：119022． doi:10.1016/j.energy.2020.119022
[4]	张建平，胡慧瑶，吴淑英，等．正交各向异性相变材料的无网格法传热模型及应用[J]．太阳能学报，2022，43(3)：242-250．
	ZHANG J P， HU H Y， WU S Y，et al ．Meshless heat transfer analysis model of orthotropic phase change materials and its application[J]．Acta Energiae Solaris Sinica，2022，43(3)：242-250．
[5]	钱怡洁．单罐斜温层蓄热性能实验研究[D]．北京：华北电力大学，2017．
	QIAN Y J ．Experimental study on the thermal energy storage performance of a single-tank slanted layer[D]．Beijing：North China Electric Power University，2017．
[6]	ELSIHY E S， LIAO Z R， XU C，et al ．Dynamic characteristics of solid packed-bed thermocline tank using molten-salt as a heat transfer fluid[J]．International Journal of Heat and Mass Transfer，2021，165：120677． doi:10.1016/j.ijheatmasstransfer.2020.120677
[7]	韩伟，叶楷，陈龙祥．基于多孔网结构的斜温层储热罐性能改进数值模拟[J]．厦门大学学报(自然科学版)，2024，63(1)：102-110．
	HAN W， YE K， CHEN L X ．Numerical simulation on performance improvement of thermocline energy storage tank based on porous mesh structure[J]．Journal of Xiamen University (Natural Science)，2024，63(1)：102-110．
[8]	SOPRANI S， MARONGIU F， CHRISTENSEN L，et al ．Design and testing of a horizontal rock bed for high temperature thermal energy storage[J]．Applied Energy，2019，251：113345． doi:10.1016/j.apenergy.2019.113345
[9]	RAO C R C， NIYAS H， MUTHUKUMAR P ．Performance tests on lab-scale sensible heat storage prototypes[J]．Applied Thermal Engineering，2018，129：953-967． doi:10.1016/j.applthermaleng.2017.10.085
[10]	LAING D， BAHL C， BAUER T，et al ．High-temperature solid-media thermal energy storage for solar thermal power plants[J]．Proceedings of the IEEE，2012，100(2)：516-524． doi:10.1109/jproc.2011.2154290
[11]	JOHN E E， HALE W M， SELVAM R P ．Development of a high-performance concrete to store thermal energy for concentrating solar power plants[C]//ASME 2011 5th International Conference on Energy Sustainability，Parts A，B，and C．Washington，DC，USA：ASMEDC，2011：523-529． doi:10.1115/es2011-54177
[12]	BOQUERA L， CASTRO J R， PISELLO A L，et al ．Thermal and mechanical performance of cement paste under high temperature thermal cycles[J]．Solar Energy Materials and Solar Cells，2021，231：111333． doi:10.1016/j.solmat.2021.111333
[13]	SKINNER J E， STRASSER M N， BROWN B M，et al ．Testing of high-performance concrete as a thermal energy storage medium at high temperatures[J]．Journal of Solar Energy Engineering，2014，136(2)：021004． doi:10.1115/1.4024925
[14]	俞海勇，王琼，张贺，等．基于全寿命周期的预拌混凝土碳排放计算模型研究[J]．粉煤灰，2011，23(6)：42-46．
	YU H Y， WANG Q， ZHANG H，et al ．Servicelife period-based carbon emission computing model for ready-mix concrete[J]．Coal Ash，2011，23(6)：42-46．
[15]	DIAGO M， INIESTA A C， SOUM-GLAUDE A，et al ．Characterization of desert sand to be used as a high-temperature thermal energy storage medium in particle solar receiver technology[J]．Applied Energy，2018，216：402-413． doi:10.1016/j.apenergy.2018.02.106
[16]	KIWAN S， SOUD Q R ．Numerical investigation of sand-basalt heat storage system for beam-down solar concentrators[J]．Case Studies in Thermal Engineering，2019，13：100372． doi:10.1016/j.csite.2018.100372
[17]	朱进容，董琼，程晓敏，等．高温混凝土储热模块充放热特性数值研究[J]．武汉理工大学学报，2013，35(12)：1-5．
	ZHU J R， DONG Q， CHENG X M，et al ．Numerical simulation on charge and discharge performance of high temperature concrete thermal storage module[J]．Journal of Wuhan University of Technology，2013，35(12)：1-5．
[18]	段后红．混凝土全寿命周期碳排放分析及减排措施[J]．建设科技，2024(1)：38-40．
	DUAN H H ．Analysis of carbon emissions throughout whole life cycle of concrete and emission reduction measures[J]．Construction Science and Technology，2024(1)：38-40．
[19]	XUE H B， WHITE A ．A comparative study of liquid，solid and hybrid adiabatic compressed air energy storage systems[J]．Journal of Energy Storage，2018，18：349-359． doi:10.1016/j.est.2018.05.016
[20]	XIE N N， WANG L， WANG Y F，et al ．Spray-type packed bed concept for thermal energy storage：liquid holdup and energy storage characteristics[J]．Applied Thermal Engineering，2019，160：114082． doi:10.1016/j.applthermaleng.2019.114082