“…The numerical results revealed that the rectangular ribs could improve the thermal performance by approximately 47.7% when compared to the plain absorber tube. A relatively large number of studies, including experimental, theoretical, and simulation, have been conducted to reveal the effects of various techniques that can improve the heat transfer enhancement potential in numerous applications such as heat exchangers, solar air heaters, solar thermal systems, solar cooling systems, solar flat-plate collectors, and solar evacuated tube collectors ( Al-Shamani et al, 2016 ; Naje et al, 2016 ; Al-Waeli et al, 2017 ; Dezfouli et al, 2017 ; HameedJaaz et al, 2017 ; Hasan et al, 2017 ; Jaaz et al, 2017 ; Hasan et al, 2018b ; Hasan et al, 2018c ; Ben Hamida and Hatami, 2021 ; Rukman et al, 2021 ; Abdulrasool et al, 2022 ; Hasan et al, 2022a ; Ameen et al, 2022 ; Hasan et al, 2022b ).…”