Effect of obstacles with different opening means on thermal stratification in hot water storage tanks

doi:10.12028/j.issn.2095-4239.2019.0055

Abstract

Abstract: The solar hot water storage tank is one of the important equipment of the solar energy application system. At present, the research on the performance of the hot water storage tank mainly focuses on the position and shape of the inlet pipe, the flow parameters, the position and geometry of the obstacle in the water tank. There is no report on the influence of the position and size of the opening of obstacles on the thermal stratification in the solar hot water storage tank. This study aims to evaluate the effect of 9 different positions of the opening of obstacles on thermal stratification and to obtain the optimal structure of the solar hot water storage tank and its optimum operating parameters. The results indicate that the tank with one circular opening in the center of the obstacle provides the optimum thermal stratification under the same flow parameters and opening area. For the tanks with multiple openings, the opening position has little effect on thermal stratification in the tank, but a significant effect on thermal energy storage. For the tank with one circular opening in the center of the obstacle, the temperature difference between the hot and cold water outlets increases first and then decreases with the increase of cold water inlet velocity under different flow parameters. When the cold water inlet velocity is greater than 0.9 m·s^-1, it will weaken the stability of thermal stratification.

Key words: solar hot water storage tank, obstacle, position of the opening, thermal stratification

CLC Number:

TU822

WANG Ye, SONG Rongfei, HU Yue, LU Hongyu. Effect of obstacles with different opening means on thermal stratification in hot water storage tanks[J]. Energy Storage Science and Technology, 2019, 8(5): 897-903.

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