Improving the thermal efficiency of parabolic trough collector using dimpled absorber tubes: an experimental investigation
摘要
The need for effective solutions for water heating presents a significant opportunity for solar energy technology, especially parabolic trough collector (PTC). Nevertheless, improving their thermal performance is the most challenging undertaking. The main objective of this study is to find the best arrangement of dimpled absorber tubes to raise a PTSC’s thermal performance for water heating applications. An experimental investigation was conducted to raise the thermal performance of a (PTC) by using dimpled absorber tube with dimples in the shape of (truncated cone). During the study, four absorber tubes are used (smooth, dimples in-line 2 sides, dimples in-line 4 sides, and dimples staggered 4 sides). The experiments were conducted in (Tikrit–Iraq) for the period (27 August 2023) to (26 September 2023) during the time from (8:00 AM) to (4:00 PM). The study’s findings demonstrated that the highest water outlet temperature is (364.15 K) obtained using a dimpled absorber tube staggered 4 sides at a volume flow rate of 0.2 L min−1 and time (1:30 PM), and the highest percentage increase in water outlet temperature using dimpled absorber tube staggered 4 sides compared to a smooth tube is 23.81% at a volume flow rate of 0.6 L min−1 and time (10:00 AM). Additionally, the experimental study demonstrated that the highest value of Nusselt number (Nu) and efficiency of the (PTC) is (11.1) and (39.428%), consequently using a dimpled absorber tube staggered 4 sides and a volume flow rate of (0.6 L min−1) and time (1:30 PM).