Economic, Exergy, and Environmental Analyses of Parabolic Trough Solar Collector with Turbulator Containing Polymer Hybrid Nanofluid

The limited resources of fossil fuels and the problems caused by greenhouse gas emissions have made it increasingly necessary to pay more attention to renewable energy sources, especially solar energy. Increasing the efficiency of equipment related to this group of energies will increase productivity, decrease fuel costs and electricity, and improve air quality. This study aims to design a new geometry for turbulators which increase efficiency in solar collectors, especially in higher Reynolds number (Re), with an increase in the Nusselt number (Nu) and a decrease in the pressure drop (DP). In this regard, the performance evaluation criterion (PEC) has been defined based on DP and Nu, and its changes have been investigated. Furthermore, the heat-transfer characteristics and performance of water-based CuO-SWCNT hybrid nanofluids (HNF), with volume fractions (ϕ) of 2% to 6% of nanoparticles in the Re = 12000 to 18000, have been investigated in the absorber tube of a solar collector. In order to couple velocity and pressure equations, a simple algorithm is used. Results from the study of two samples of twisted tape (TT) with two different scales (1 and 0.5) are examined for samples A and B respectively. Based on the results, the TT with a scale has the highest efficiency of 1.0 (Re =12000, f = 2% is 3.54) where it is 3.52, while considering a TT with a scale of 0.5 under the same conditions. Therefore, using a TT with a scale of 1 is more desirable from a thermal fluid dynamics point of view.