HEAT-TRANSFER ENHANCEMENT OF A SOLAR PARABOLIC TROUGH COLLECTOR USING TURBULATORS AND NANOPARTICLES: A NUMERICAL STUDY

Abstract

Solar energy harnessing devices exhibit promising potential for providing a significant portion of the energy requirement. Among these devices, the solar parabolic trough collector (PTC) is a well-renowned and effective technology. In recent times, a great deal of research has been done further improving the thermal performance of PTC systems. The current numerical study investigates the effect of modifications to the geometry of the absorber tube and the effect of nanoparticles on the thermal performance of PTC. A corrugated tube (CT), sinusoidal corrugated tube (SCT), the corrugated tube having a cylindrical insert (CI), star insert (SI), and increasing diameter rod insert (IDRI) are used to modify the geometry of the absorber tube. The corrugated tube is also analyzed with water-Al<sub>2</sub>O<sub>3</sub> and water-TiO<sub>2</sub> nanofluids at volume concentrations of 2%, 4%, and 6%. The results showed that the sinusoidal corrugated tube produced the best results with a value of Nusselt number (Nu) being 15.2% greater than simple corrugated absorber tube without incurring any significant increase in pressure. Moreover, the performance evaluation criterion (PEC) value is also found to be greater than that of simple corrugated geometry. The use of nanofluids as the heat-transfer fluid (HTF) led to an overall enhancement in the heat transfer coefficient h by as much as 20%.