Thermal performance enhancement of nanofluids based parabolic trough solar collector (NPTSC) for sustainable environment

Abstract

Due to rapid industrialization and urbanization, upward rise in carbon emissions in the atmosphere, and depletion of fossil fuel and gas reserves have forced to find alternative renewable energy resources, where solar energy is one of the most promising source. Parabolic trough solar collectors (PTCs) can effectively transfer high temperature in the tube of receiver upto 400 °C. In this study, Computational Fluid Dynamics (CFD) analysis is used to analyse the effect of multiple working fluids on efficiency of the PTC. Two different types of nanofluids used for analyising the thermal efficiency of PTC through CFD simulations, are Alumina and Copper-oxide nanofluids. The concentration of Copper Oxide and Alumina was kept to 0.01% in the nanofluids. The efficiency for PTC is calculated at two different mass flow rates i.e., 0.0112 Kg/s and 0.0224 Kg/s. The highest efficiency is 13.01 and 13.1% using Al2O3 as nanofluids at 0.0112 Kg/s and 0.0224 Kg/s flow rates, while CuO has an efficiency of 13.92% and 14.79% for these flow rates. The behaviour of absorber tube material on temperature distribution for steel, copper and aluminum as absorber tube material was also investigated. Changing the material from steel to copper and aluminum increased the outlet temperature of the fluid. The maximum output temperature was achieved for copper is 311 K while steel and aluminum showed lower temperature of 307 K and 308 K of the fluid at the outlet. Furthermore, the impact of the receiver tube's length on the working fluid's temperature is also studied. Copper Oxide nanofluid has higher temperature at the outlet for both mass flow rates as compared to alumina nanofluid. Accordingly, a comparison was made for the CFD results with the experimental findings from literature. The nanofluids based PTCs system is promising method for the sustainable environment applications.