Thermal performance augmentation of parabolic trough solar collector using nanomaterials, fins and thermal storage material

Abstract

Investigating and evaluating parabolic trough collector's (PTC) thermal performance have been shed out numerically by many researchers. Only a few researchers have focused their attention on using experiments to study the PTC's thermal performance. Consequently, the objective of this paper is to utilize an experimental method to put more shed on the PTC performance using active and passive methods. This aim is achieved by developing an experimental setup with modifications in reference parabolic trough collector (RPTC) and employing different heat transfer fluids. RPTC modifications include adding fins to the outer tube surface (FPTC), coating the absorber with Copper Oxide nanoparticles (CuO) combined with black paint (NCPTC), and filling the annulus with graphite (GPTC). Heat Transfer fluid (HTF) is changed by inserting CuO nanoparticles into water (NFPTC). All experiments are performed during August 2021 in Kafrelsheikh University. Data such as: inlet and exit temperatures of HTF, air temperature, air speed, solar irradiation, and rate of mass flow of HTF are recorded hourly for RPTC, NFPTC, NCPTC, NF-NCPTC, FPTC, and GPTC. Based on these data, thermal efficiency is calculated. FHT mass flow rate is controlled and typical values of 8, 10, 14, 16, 20, and 26 l/h are employed with RPTC in purpose to explore the optimum value based on practical considerations, HTF temperature difference, and higher efficiency. This value is found to be 20 l/h and is used in all modified collectors. All modified collectors' thermal performance is studied and compared with the traditional collector. The main finding in present study indicates that there is an augmentation in the thermal efficiency by 19.18 %, 26.23 %, 37.76 %, 44.43 %, and 54.82 % for NFPTC, NCPTC, NF-NCPTC, FPTC, and GPTC respectively when compared with RPTC.