Experimental investigation of thermal efficiency and thermal performance improvement of compound parabolic collector utilizing SiO2/Ethylene glycol–water nanofluid

• Published in: Environmental science and pollution research international Vol. 30; no. 5; pp. 12169 - 12188
• Main Authors: Khaledi, Omid, Saedodin, Seyfolah, Rostamian, Seyed Hadi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2023
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Research Article; Waste Water Technology; Water Management; Water Pollution Control; Nanofluid containing silica; Compound parabolic collector (CPC); Thermal efficiency; Heat transfer; Experimental investigation
• ISSN: 1614-7499; 1614-7499
• DOI: 10.1007/s11356-022-22848-6

A compound parabolic collector has been used in the present study to lower operating costs per unit of heat increase compared to other tracker concentrators. This type of collector has been given more attention in industrial and domestic applications in the temperature range of 60 to 300 °C. Also, to increase the thermal efficiency, nanofluid containing SiO 2 nanoparticles in ethylene glycol–water hybrid base fluid (10–90 vol.%) have been used in three different volumetric fractions. The innovation of this present study includes the utilization of mentioned nanofluids for the first time in this collector, which has good stability and is cost-effective compared to other nanoparticles. In addition, the experimental measurement of thermal and hydraulic properties of nanofluids represents new aspects of the present study. The experiments used three volumetric fractions of 0.5%, 1%, and 1.5% under extensive solar radiation. Thermal performance of the collector at four volumetric flow rates of 1, 1.5, 2, and 2.5 Lit/min have been investigated according to ASHRAE standard 93–2010 (RA2014). According to the experimental data, the thermal efficiency of the collector improved by 5% to 11.6% when the nanofluid was applied. The maximum enhancement of the average Nusselt number of the nanofluid versus the base fluid at the volumetric flow rate of 1 Lit/min and the volumetric fraction of 1.5% was equal to 7.3%. Besides, nanofluid increased the pressure drop, and consequently, the pumping power slightly. Finally, considering both the impacts of heat transfer and pressure drop, performance evaluation criteria and overall efficiency for nanofluid have been analyzed. The results represented that in all volumetric fractions, the values of performance evaluation criteria and overall efficiency enhanced compared to the base fluid. This research provides researchers and engineers with important information to better understand the thermal and hydraulic parameters of the parabolic compound concentrator in the presence of nanofluid to improve its thermal performance. The results also highlight the potential of using SiO 2 nanoparticles to improve the thermal efficiency of solar collectors despite their low thermal conductivity compared to other conventional nanoparticles.