Optimization of the tank position and aspect ratio by the Box-Behnken method for enhancement of thermal stratification in a hot water tank
Abstract
Thermal stratification in hot water storage systems ensures that the hot water temperature in the tank can be maintained for a longer time and the energy of the heat source can be utilized more efficiently. In the literature, many experimental and numerical studies have been carried out to increase the thermal stratification by changing the tank design. In this study, however, it was aimed to increase the thermal stratification in the tank by only changing the position of the tank. The effects of the angle of the tank with the horizontal axis (α) and the tank aspect ratio (D/H) on thermal stratification were investigated numerically. Also, an optimization was carried out with the Box-Behnken method to determine the most suitable aspect ratio and tank position in terms of thermal stratification and second law efficiency. As a result of the optimization process, it was determined that the most suitable α angle was 47.23˚ and the D/H ratio was 0.922. Depending on these parameter values, the temperature difference and second law efficiency in the tank were obtained as 11,651˚ and 0.898, respectively. The results of the analysis revealed that the applied method can contribute to the formation of thermal stratification in hot water tanks.
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