Performance evaluation of TiN/water nanofluid charged U-pipe evacuated tube solar thermal collector with twisted tape inserts

The evacuated U-pipe solar thermal collector appears most congruent and efficient for solar thermal applications. The TiN nanofluid-charged evacuated U-pipe solar thermal collector convective heat transfer performance, pressure drop, efficiency, performance index, heat absorbed, and removal factor are evaluated using ASHRAE Standard 93–2003. Stable TiN nanofluid forge by suspending 40–50 nm-sized TiN nanoparticles in distilled water at volume concentrations of 0%, 0.025%, 0.050%, 0.075%, and 0.1%. TiN nanofluid stability and thermophysical properties of the deliberated experimentally. The outdoor trials were conducted at latitudes 19.5761 degrees N and 74.2070 degrees E using twisted tape (H/D = 5) at a flow rate of 0.25–1.25 LPM and volume concentrations of 0.0–0.1%. The combination of twisted tape (H/D = 5) and 0.1% TiN nanofluid leads to a 475.37% convective heat transfer coefficient enhancement at a 1.25 LPM flow rate compared to water at a 0.25 LPM flow rate. Under the same operating conditions, the pressure drop has improved by 64%. TiN nanofluid-charged solar thermal collectors have an efficiency of 80.47% at 0.1% volume concentration when combined with twisted tape. TiN nanofluid with a volume concentration of 0.025%, a flow rate of 1.25LPM, and a twisted tape configuration achieved an intense performance index of 1.58.