Experimental analysis of the effect of copper dimple tube with aluminum coating on the performance of parabolic solar water heater using helically twisted tape

• Published in: Advances in mechanical engineering Vol. 16; no. 7
• Main Authors: Munusamy, Arun, Barik, Debabrata, Chandran, Sreejesh S.R., Reby Roy, K.E., Paramasivam, Prabhu, Shreedhara Murthy, Sunil
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.07.2024; Sage Publications Ltd; SAGE Publishing
• Subjects: Aluminum; Aluminum coatings; Coating effects; Convective heat transfer; Copper; Dimpling; Friction factor; Heat transfer coefficients; Helical flow; Mass flow rate; Performance evaluation; Pressure drop; Solar collectors; Solar energy; Solar heating; Space heating; System effectiveness; Texturing; Tubes; Uncertainty; Water heaters; Water heating; twisted tape; copper dimple tube; Parabolic solar water heater; aluminum coating; performance analysis
• ISSN: 1687-8132; 1687-8140
• DOI: 10.1177/16878132241262679

In this research, a parabolic trough solar water heater (PTSWH) having helically twisted copper tubes and dimple texturing with an aluminum (AlC) coat was experimentally examined to identify the solar collector’s efficiency, friction factor, convective heat transfer, Nusselt numbers variations, and uncertainty during the test. For this purpose, helical copper dimple tubes with Al coating were used to pass water through it at mass flow rates of 0.5–2.5 kg/min, with 0.5 kg/min increments. Experimental tests were conducted using specific datasets to investigate the efficacy of PTSWH. These experiments aimed to evaluate the efficiency and performance of solar collectors in harnessing solar energy for various applications, such as space heating, water heating, and industrial processes. The results of these experiments are recorded and analyzed to assess the practical viability of solar thermal systems. The results showed that solar collector effectiveness was improved by about 31.2% at flow rates of 1.5 kg/min, while the friction factor was raised by approximately 0.23%. The convective heat transfer coefficient was enhanced by about 7%, and the Nusselt numbers were enhanced to nearly 298. The overall uncertainty of ±2.3% was also observed, indicating that the findings were within the permissible range. Moreover, the PTSWH system recorded an elevated pressure drop of 2.32 kPa. This approach of dimple texturing with Al coating may be best suited for the PTSWHs used in moderate and low solar intensity regions.