Performance investigation of an all glass evacuated tube solar collector with an innovative heat exchanger design using TiO2-H2O nanofluids- an experimental study

Abstract

ABSTRACT The objective of the current study is to experimentally analyze the thermal performance of an all-glass evacuated tube solar collector (ETSC) with an innovative heat exchanger design by employing TiO2-H2O nanofluid as a heat transmission fluid. Different higher volume concentration (v/c) of TiO2 nanoparticles, i.e. 0.83%, 0.9%, and 0.94% are examined to explore the impact of the nanofluids on the ETSC performance in comparison with only water based ETSC. An outdoor experimental investigation has been carried out using nanofluid at 0.6, 0.7 and 0.8 l/min volumetric rates of flow and its impact using serpentine copper tube coil having uniform pitch distance of 14.3 cm with aluminum fins attached on both side of coil having diameter 12 mm and thickness 1 mm, respectively. The study indicates that thermal performance of ETSC increases with the rise in volumetric flow rate with higher v/c of nanoparticles. For this condition, the temperature rise of water using nanofluid is higher than simple water-based ETSC system, recording an increase in outlet temperature by 4.21%. The maximum thermal efficiency obtained is 52.33% at 0.9% v/c and 0.8 l/min. A comparative assessment between the obtained results and some of the published results reveals that by using serpentine copper coil attached with aluminum fins, with higher concentrations of TiO2 nanoparticles and maintaining higher volumetric flow rate, thermal efficiency of ETSC can be much improved.