Numerical and experimental study of an underground water pit for seasonal heat storage

RENEWABLE ENERGY

卷:150

Article

Bai, Yakai^{1,2,3,4,5,6,7,8}  Wang, Zhifeng^{1,2,3,5,6,7,8}  Fan, Jianhua⁴  Yang, Ming^{1,2,3,5,6,7,8}  Li, Xiaoxia^{1,2,5,6,7,8,9}  Chen, Longfei^{1,2,5,6,7,8,9}  Yuan, Guofeng^{1,2,3,5,6,7,8}  Yang, Junfeng^{1,2,3,5,6,7,8} 

[1] Chinese Acad Sci, Key Lab Solar Thermal Energy & Photovolta Syst, Beijing 100190, Peoples R China

[2] Chinese Acad Sci, Inst Elect Engn, Beijing 100190, Peoples R China

[3] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

[4] Tech Univ Denmark, Dept Civil Engn, Brovej 118, DK-2800 Lyngby, Denmark

[5] Beijing Engn Res Ctr Solar Thermal Power, Beijing 100190, Peoples R China

[6] Beijing CSP Int Cooperat Ctr, Beijing 100190, Peoples R China

[7] Chinese Acad Sci, Inst Elect Engn, Joint Lab, Beijing 100190, Peoples R China

[8] Guangdong Five Star Solar Energy Co Ltd, Beijing 100190, Peoples R China

[9] Lanzhou Univ Technol, Lanzhou 730050, Peoples R China

关键词: Water pit;    Seasonal heat storage;    Thermal stratification;    Numerical validation;   

DOI  :  10.1016/j.renene.2019.12.080

来源: Elsevier

【 摘 要 】

Water pit heat storage is an important part of smart district heating systems that integrate various renewable energy sources. This project studied the storage capacity and thermal stratification in a 3000 m(3) underground water pit in Huangdicheng, China using a finite difference model of the water pit that was validated by experimental data. The total heat loss from the water pit in the first year was measured to be 98 MWh and the storage efficiency was 62%. Further investigations using the validated model show that approximately 57% of the total heat loss took place through the side wall, 30% through the top and the rest through the bottom of the pit. The heat loss coefficient was largest along the side wall at 0.702 W m(-2).degrees C-1. Higher charging temperatures create higher temperature differences between the top and bottom of the water pit, i.e. greater thermal stratification. The MIX number increases during most of the charging period and cannot represent the thermal stratification in the water pit during charging while the stratification number more accurately represents the stratification. Therefore, the stratification number is recommended for characterizing stratified water pits. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

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