Comparative study of the transient natural convection in an underground water pit thermal storage

doi:10.1016/j.apenergy.2017.09.036

	Comparative study of the transient natural convection in an underground water pit thermal storage
	Chang, Chun 1,2,3; Wu, Zhiyong 1,3; Navarro, Helena 2; Li, Chuan 2; Leng, Guanghui 2; Li, Xiaoxia1,3,4 ; Yang, Ming 1,3; Wang, Zhifeng 1,3; Ding, Yulong 2
	2017-12-15
发表期刊	APPLIED ENERGY
ISSN	0306-2619
卷号	208 页码:1162-1173
摘要	This study investigated the transient natural convection phenomenon in an underground water pit thermal storage with heat losses through the surrounding walls. An experimental test rig was built up, and a numerical model was developed to obtain the characteristics of the thermal stratification in the water pit thermal storage. Fluid properties are assumed to be constant, except for the density changes with temperature which is treated using the Boussinesq approximation. The simulations of temperature profiles are reasonably proved by experiments with the maximum relative errors of +/- 9.77%. The results show that water temperature decreases close to the walls due to the heat losses, which leads to a downward flow along the inclined sidewalls. A slight upward flow occurs at the center of the water pit thermal storage, which lifts the warmer water to a higher level. As a result, the buoyancy-driven flow gradually builds up the thermal stratification in the water pit thermal storage. The modelling results also show that the values of the average Nusselt numbers on the inner surface of the inclined sidewalls and the bottom of the tank are much higher than that of the top thermal insulation layer. The thermal energy storage efficiency decreases rapidly in the first five minutes from 100% to 83.19% due to the intense heat transfer, and then tends to level off at the end of 40 min. The maximum velocity of the natural convection appears close to the upper part of the inclined sidewalls, and it decreases with the cooling process evolved. The present work has a valuable attempt to fill the gap in the existing studies and is useful for guiding the water pit thermal storage design.
关键词	Natural convection Water pit thermal storage Boussinesq approximation Buoyancy-driven flow Thermal stratification Efficiency
DOI	10.1016/j.apenergy.2017.09.036
收录类别	SCI ; SCIE
语种	英语
资助项目	China Scholarship Council (CSC)[201604910091]
WOS研究方向	Energy & Fuels ; Engineering
WOS类目	Energy & Fuels ; Engineering, Chemical
WOS记录号	WOS:000416300400087
出版者	ELSEVIER SCI LTD
EI入藏号	20173804179899
EI主题词	Thermal insulation
EI分类号	408.2 Structural Members and Shapes - 413.2 Heat Insulating Materials - 444.2 Groundwater - 525.2 Energy Conservation - 641.2 Heat Transfer - 913.1 Production Engineering - 931.2 Physical Properties of Gases, Liquids and Solids
引用统计	被引频次：45[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/32968
专题	能源与动力工程学院
通讯作者	Wu, Zhiyong
作者单位	1.Chinese Acad Sci, Inst Elect Engn, Key Lab Solar Thermal Energy & Photovolta Syst, Beijing 100190, Peoples R China; 2.Univ Birmingham, Birmingham Ctr Energy Storage, Birmingham B15 27T, W Midlands, England; 3.Beijing Engn Res Ctr Solar Thermal Power, Beijing 100190, Peoples R China; 4.Lanzhou Univ Technol, Coll Energy & Power Engn, Lanzhou 730050, Gansu, Peoples R China
推荐引用方式 GB/T 7714	Chang, Chun,Wu, Zhiyong,Navarro, Helena,et al. Comparative study of the transient natural convection in an underground water pit thermal storage[J]. APPLIED ENERGY,2017,208:1162-1173.
APA	Chang, Chun.,Wu, Zhiyong.,Navarro, Helena.,Li, Chuan.,Leng, Guanghui.,...&Ding, Yulong.(2017).Comparative study of the transient natural convection in an underground water pit thermal storage.APPLIED ENERGY,208,1162-1173.
MLA	Chang, Chun,et al."Comparative study of the transient natural convection in an underground water pit thermal storage".APPLIED ENERGY 208(2017):1162-1173.

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