An experimental investigation of nanofluid, nanocoating, and energy storage materials on the performance of parabolic trough collector

Abstract

Currently, parabolic trough collectors have been widely employed for medium-high heat generation applications such as heat generation processes and desalination applications. Hence, this study tries to enhance the thermal performance of the traditional parabolic trough collector by several methods, including the use of Nanotechnology and thermal energy storage materials. An experimental setup was carried out in Kafrelshiekh city, Egypt to investigate the influence of the enhancing methods used on the thermal performance of PTC. Due to its high accuracy and the fact that many recent articles used numerical techniques without validating their findings, the experimental method is used. The study's enhancing techniques involve the use of many passes of the absorber tube, the use of TiO2 nanofluid as the heat transfer fluid, coating the absorber tube, and without employing a vacuum, reducing thermal losses caused by the presence of air by using a thermal energy storage material (graphite) in the annulus. After that, a comprehensive comparison between all cases is performed to indicate the most effective method. The performed comparative investigation showed that there is an enhancement in the thermal efficiency by 39.3%, 54.2%, 57.7%, 70.5%, and 85.4% when using the new absorber tube configuration, coating the absorber tube, using TiO2 nanofluid as the heat transfer fluid, using the previous methods together, and finally using a thermal energy storage material (graphite) in the annulus with the last modified system, respectively, as compared with that of the reference parabolic trough collector system. Hence, the proposed system was the G PTC as it offered the highest average thermal efficiency and conserved an approximately constant efficiency that was close to the maximum value during the whole day.