Effect of rectangular hot water tank position and aspect ratio on thermal stratification enhancement

• Published in: Renewable energy 2018-02, Vol.116, p.639-646
• Main Authors: Kurşun, Burak, Ökten, Korhan
• Format: Article
• Language: English
• Subjects: Energy storage; Natural convection; Thermal stratification; Water tank
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2017.10.013

Thermal stratification is an important factor increasing the efficiency of hot water storage tanks used for thermal energy storage. In this study, the effects of the position of a rectangular hot water tank and the aspect ratio on the thermal stratification were investigated numerically. In this direction, a numerical analysis was carried out for the different angle of the water tank with the horizontal axis (α) and the different aspect ratio of the water tank (D/H). Numerical analyses were performed at 0–60° range of angle values and 0.5–1 range of aspect ratio values. The results obtained from the analyses indicate that positioning of the hot water tank at different values from α = 0° provides thermal stratification enhancement. Reducing the aspect ratio of the tank contributes to the thermal stratification only for the angle of α = 0° significantly. In other angle values, the influence of different aspect ratios on the thermal stratification is negligible level. The highest temperature difference in the hot water tank occurred for the angle of α = 45° and aspect ratio of D/H = 0.5. •The inclined placement of the rectangular hot water tank increases the thermal stratification.•The change in aspect ratio increase the thermal stratification enhancement for the vertical position of the tank.•The change in tank position and aspect ratio causes exergy destruction at negligible level.•Reducing the tank aspect ratio also decreases the thermal storage capacity.