Influence of tank shape on heat storage performance： A numerical study

doi:10.19799/j.cnki.2095-4239.2022.0315

Abstract

Abstract:

Thermal storage can solve the intermittent problem of solar energy, which is providing a stable thermal output and improving energy quality. Solid-liquid phase change heat storage has attracted attention due to its advantages of large heat storage density and relatively constant temperature during heat storage/release. However, during solid-liquid phase change heat storage, there is constant inhomogeneity in the melting times and temperatures of the phase change materials (PCMs). The refractory zone greatly prolongs the overall phase change heat storage time. Therefore, this paper proposes improving the unevenness of the melting times by changing the shape of the heat storage tank. Five trapezoidal phase change heat storage tanks with different gradient ratios were designed. The heat storage performance of these tanks were examined using numerical simulations. The results indicated that increasing the proportion of PCMs in the upper region was conducive to the timely transfer of heat to the unmolten PCMs and reduced the resistance of heat transfer, thereby improving the overall heat transfer rate. The complete melting time of Cases 1 and 2 with a larger proportion of PCMs in the upper region was shortened compared to that of Case 3, with reduction ratios of 39.06% and 29.37%, respectively.

Key words: latent heat storage, solid-liquid phase transition, trapezoid heat storage tank, phase interface, heat transfer resistance

CLC Number:

TQ 051

Jun ZHANG, Fengxia ZHAO, Zhao DU, Kang YANG, Yuanji LI, Xiaohu YANG. Influence of tank shape on heat storage performance： A numerical study[J]. Energy Storage Science and Technology, 2022, 11(11): 3674-3680.

Figures/Tables 10

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References 19

1	王俊, 曹建军, 张利勇, 等. 基于分布式能源系统的蓄冷蓄热技术应用现状[J]. 储能科学与技术, 2020, 9(6): 1847-1857.
	WANG J, CAO J J, ZHANG L Y, et al. Review on application of cold storage and heat storage technology based on distributed energy system[J]. Energy Storage Science and Technology, 2020, 9(6): 1847-1857.
2	金光, 肖安汝, 刘梦云. 相变储能强化传热技术的研究进展[J]. 储能科学与技术, 2019, 8(6): 1107-1115.
	JIN G, XIAO A R, LIU M Y. Research progress on heat transfer enhancement technology of phase change energy storage[J]. Energy Storage Science and Technology, 2019, 8(6): 1107-1115.
3	李拴魁, 林原, 潘锋. 热能存储及转化技术进展与展望[J]. 储能科学与技术, 2022, 11(5): 1551-1562.
	LI S K, LIN Y, PAN F. Research progress in thermal energy storage and conversion technology[J]. Energy Storage Science and Technology, 2022, 11(5): 1551-1562.
4	邹勇, 仇汝冬, 王霞. 石蜡相变材料蓄热过程的模拟研究[J]. 储能科学与技术, 2020, 9(1): 101-108.
	ZOU Y, QIU R D, WANG X. Simulation study on thermal storage process of paraffin phase change materials[J]. Energy Storage Science and Technology, 2020, 9(1): 101-108.
5	ZHANG T Y, YU M F, LI J, et al. Effect of porosity gradient on mass transfer and discharge of hybrid electrolyte lithium-air batteries[J]. Journal of Energy Storage, 2022, 46: doi: 10.1016/j.est.2021.103808.
6	洪杰, 孙明生, 罗显峰, 等. 水平及竖直放置套管式相变蓄热单元传热特性的数值模拟[J]. 热能动力工程, 2020, 35(11): 74-80.
	HONG J, SUN M S, LUO X F, et al. Numerical simulation on heat transfer characteristics of double pipe latent heat storage unit placed horizontally and vertically[J]. Journal of Engineering for Thermal Energy and Power, 2020, 35(11): 74-80.
7	杜昭, 阳康, 舒高, 等. 金属泡沫内石蜡固液相变蓄热/放热实验[J]. 储能科学与技术, 2022(2): 531-537.
	DU Z, YANG K, SHU G, et al. Experimental study on the heat storage and release of the solid-liquid phase change in metal-foam-filled tube[J]. Energy Storage Science and Technology, 2022(2): 531-537.
8	HUANG Y P, CAO D C, SUN D K, et al. Experimental and numerical studies on the heat transfer improvement of a latent heat storage unit using gradient tree-shaped fins[J]. International Journal of Heat and Mass Transfer, 2022, 182: doi: 10.1016/j.ijheatmasstransfer.2021.121920.
9	CHEN K, MOHAMMED H I, MAHDI J M, et al. Effects of non-uniform fin arrangement and size on the thermal response of a vertical latent heat triple-tube heat exchanger[J]. Journal of Energy Storage, 2022, 45: doi: 10.1016/j.est.2021.103723.
10	SODHI G S, MUTHUKUMAR P. Compound charging and discharging enhancement in multi-PCM system using non-uniform fin distribution[J]. Renewable Energy, 2021, 171: 299-314.
11	YANG X H, GUO J F, YANG B, et al. Design of non-uniformly distributed annular fins for a shell-and-tube thermal energy storage unit[J]. Applied Energy, 2020, 279: doi: 10.1016/j.apenergy. 2020.115772.
12	TIARI S, HOCKINS A, MAHDAVI M. Numerical study of a latent heat thermal energy storage system enhanced by varying fin configurations[J]. Case Studies in Thermal Engineering, 2021, 25: doi: 10.1016/j.csite.2021.100999.
13	LIU G, XIAO T, GUO J F, et al. Melting and solidification of phase change materials in metal foam filled thermal energy storage tank: Evaluation on gradient in pore structure[J]. Applied Thermal Engineering, 2022, 212: doi: 10.1016/j.applthermaleng.2022.118564.
14	ZHENG Z J, YANG C, XU Y, et al. Effect of metal foam with two-dimensional porosity gradient on melting behavior in a rectangular cavity[J]. Renewable Energy, 2021, 172: 802-815.
15	WANG Z F, WU J N, LEI D Q, et al. Experimental study on latent thermal energy storage system with gradient porosity copper foam for mid-temperature solar energy application[J]. Applied Energy, 2020, 261: doi: 10.1016/j.apenergy.2019.114472.
16	贾兴龙, 陈宝明, 张艳勇, 等. 梯度骨架对固液相变蓄热特性影响研究[J]. 山东建筑大学学报, 2020, 35(5): 56-63.
	JIA X L, CHEN B M, ZHANG Y Y, et al. Study on the effect of gradient skeleton on the heat storage characteristics of solid-liquid phase change[J]. Journal of Shandong Jianzhu University, 2020, 35(5): 56-63.
17	何贤德. 梯度孔隙率泡沫金属复合相变材料蓄热过程研究[D]. 北京: 北京交通大学, 2017.
	HE X D. Investigation on the process of thermal heat storage of metal foam composite phase change material with porosity gradient[D]. Beijing: Beijing Jiaotong University, 2017.
18	MARRI G K, BALAJI C. Experimental and numerical investigations on the effect of porosity and PPI gradients of metal foams on the thermal performance of a composite phase change material heat sink[J]. International Journal of Heat and Mass Transfer, 2021, 164: doi: 10.1016/j.ijheatmasstransfer.2020.120454.
19	LONGEON M, SOUPART A, FOURMIGUÉ J F, et al. Experimental and numerical study of annular PCM storage in the presence of natural convection[J]. Applied Energy, 2013, 112: 175-184.

模型	R₁/R₂	R₁/mm	R₂/mm
模型1	5∶1	70.0	14.0
模型2	3∶1	64.9	21.6
模型3	1∶1	45.0	45.0
模型4	3∶1	21.6	64.9
模型5	5∶1	14.0	70.0

物理量	石蜡RT35	单位
ρ	785.0	kg/m³
c_p	2850.0	J/(kg·K)
λ	0.2/0.1	W/(m·K)
T_m	50.0～55.0	℃
L	102.1	kJ/kg
υ	3.7×10^-3	m²/s
α	3.1×10^-4	1/K

模型	网格数	时间步长/s	8000 s时熔化率
模型2	33504	0.10	0.359
模型2	83514	0.10	0.353
模型2	156938	0.10	0.348
模型2	83514	0.05	0.352
模型2	83514	0.50	0.330

[1]	Zhu JIANG, Boyang ZOU, Lin CONG, Chunping XIE, Chuan LI, Geng QIAO, Yanqi ZHAO, Binjian NIE, Tongtong ZHANG, Zhiwei GE, Hongkun MA, Yi JIN, Yongliang LI, Yulong DING. Recent progress and outlook of thermal energy storage technologies [J]. Energy Storage Science and Technology, 2022, 11(9): 2746-2771.
[2]	Zhao DU, Kang YANG, Gao SHU, Pan WEI, Xiaohu YANG. Experimental Study on the Heat Storage and Release of the Solid-Liquid Phase Change in Metal-Foam-Filled Tube [J]. Energy Storage Science and Technology, 2022, 11(2): 531-537.
[3]	Yongliang SHEN, Pengwei ZHANG, Shuli LIU. Three-dimensional numerical study of discharging characteristics of a fin-enhanced cascaded latent heat storage system [J]. Energy Storage Science and Technology, 2022, 11(11): 3558-3565.
[4]	Fan WANG, Zhao DU, Kang YANG, Xinyi WANG, Rukun HU, Xiaohu YANG. Experimental study on solidification of metal foam composite phase change material in a horizontal heat storage tube [J]. Energy Storage Science and Technology, 2022, 11(11): 3667-3673.
[5]	LING Haoshu, HE Jingdong, XU Yujie, WANG Liang, CHEN Haisheng. Status and prospect of thermal energy storage technology for clean heating [J]. Energy Storage Science and Technology, 2020, 9(3): 861-868.
[6]	HAN Guangshun, WANG Peilun, JIN Yi, HUANG Yun, DING Hongsheng, DING Yulong. Numerical simulations on performance enhancement of a cross-flow latent thermal energy storage heat exchanger [J]. Energy Storage Science and Technology, 2015, 4(2): 183-188.
[7]	LIU Yongkun, TAO Yubing, TANG Zongbin. Numerical study on performance enhancement of latent heat storage unit [J]. Energy Storage Science and Technology, 2014, 3(3): 197-202.