Experimental investigation on enhancement of thermal performance with obstacle placing in the horizontal hot water tank used in solar domestic hot water system. (August 2019)

• Record Type: Journal Article
• Authors: Erdemir, Dogan; Atesoglu, Hakan; Altuntop, Necdet
• Is Part Of: Renewable energy. Volume 138(2019)
• Page Start: 187
• Page End: 197
• Publication Date: 2019-08
• Subjects: Horizontal hot water tank -- Solar domestic hot water system -- Thermal performance -- Obstacle -- Sensible thermal energy storage; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2019.01.075
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Horizontal mantled hot water tanks are widely used in solar domestic hot water systems. Increasing thermal performance of the hot water tank is significant issue for thermodynamic efficiencies of the system and user satisfaction. This study presents an experimental study for determining the effect of obstacle placing on thermal performance in horizontal mantled hot water tank. Obstacles were positioned perpendicular to the flow direction inside the tank in different positions. First, one obstacle was placed inside the tank in different positions and then two obstacles were placed inside the tank. Results were presented over the temperature distribution inside the tank, mantle outlet temperature, main outlet temperature, energy efficiency and exergy efficiency. At the end of the study, it was found that obstacle placing in horizontal mantled hot water tank increased the thermal performance of tank. Temperature distribution results showed that placing obstacle inside the tank increased stored hot water temperature and volume. Mantle outlet temperature could be decreased 1.5 °C, and the main outlet temperature could be increased 3.6 °C by placing obstacles inside the tank. Consequently, when all performance criteria considered, the best thermal performances were seen in a = 150 mm, a = 150 mm b = 100 mm and a = 350 mm b = 100 mm. Highlights: Although horizontal mantled hot water tanks are widely used in solar domestic hot water systems, thermal performance of horizontal mantled hot water tanks is generally lower than vertical hot water tanks. This study presents an experimental study investigating the enhancement of thermal performance with obstacle placing in the horizontal mantled hot water tank. Since obstacles have behaved as flow and thermal barriers, the volume and temperature of stored hot water have been increased by placing obstacles. Mantle outlet temperature could be decreased 1.5 °C, and the main outlet temperature could be increased 3.6 °C by placing obstacles inside the tank. While energy efficiencies were over 95% in all cases, exergy analyses gave more realistic comparison for the different cases and they changed between 8% and 19%.