Experimental investigation of convective heat transfer performance of TiN nanofluid charged U-pipe evacuated tube solar thermal collector

• Published in: Applied thermal engineering 2023-05, Vol.225, p.120199, Article 120199
• Main Authors: Deshmukh, Kishor, Karmare, Suhas, Patil, Pradeep
• Format: Article
• Language: English
• Subjects: Collector efficiency; Convective heat transfer; TiN nanofluid; U-pipe solar collector
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2023.120199

[Display omitted] •The preparation, characterization, and experimental investigation of TiN nanofluid thermophysical properties are discussed.•The performance of a TiN nanofluid-charged U-pipe evacuated tube solar thermal collector's convective heat transfer is examined.•The effect of TiN nanoparticle volume concentration and flow rate on the performance of convective heat transfer is investigated. The present study investigates the convective heat transfer performance of the U-pipe evacuated tube solar thermal collector with TiN nanofluid. TiN nanoparticles 40–50 nm in size dispersed in distilled water at 0 %, 0.025 %, 0.050 %, 0.075 %, and 0.1 % volume concentrations. The TiN nanofluid's stability and thermophysical properties are measured experimentally. ASHRAE standard 93-2003 evaluates collector thermal performance. The convective heat transfer coefficient, friction factor characteristic, and solar thermal efficiency are investigated experimentally at volume concentrations of 0 %, 0.025 %, 0.050 %, 0.075 %, and 0.10 %, and mass flow rates of 0.25, 0.50, 0.75, and 1 LPM. The solar thermal collector performance is tested in Sangamner at latitudes of 19.576°N and 74.2070°E under outdoor test conditions. The TiN nanofluid with a 0.1 % volume concentration at a 1.25 LPM flow rate gives a 109.6 % enhancement in the convective heat transfer coefficient compared to water. The friction factor penalty of TiN nanofluid at 0.1 % volume concentration is 2.58 and 1.82 for water. At 0.1 % volume concentration, the solar thermal collector efficiency reaches 70.9 %. The correlation is proposed to determine the Nusselt number, friction factor, and solar thermal efficiency in laminar flow. The TiN nanofluid is recommended for industrial solar thermal applications because of its notable improvement in convective heat transfer performance despite the friction factor penalty.