Numerical study of thermal performance enhancement in rectangular channel flat-plate solar collector due to fractured micro-rectangular staggered ribs

The effect of fractured micro-rectangular staggered ribs on thermal performance enhancement of flat-plate solar collector (FPSC) is studied in present study. Three new rib parameters named as relative rib height (e/Dh), relative longitudinal distance of rib (l/c), and relative transverse distance of rib (t/w) are defined and their influences on thermal performance of rectangular channel collector is simulated using commercial ANSYS software under fixed range of Reynolds number (Re) which varies from 94 to 567. The e/Dh, l/c, and t/w range from 0.13 to 0.40, 30.0 to 61.5, and 1 to 3, respectively. A three-dimensional model of collector is established and the results are simulated using finite volume method. A Performance Evaluation Criteria (PEC) is employed for balancing heat transfer enhancement and required pumping power. In the case of e/Dh = 0.40, l/c = 30.0, t/w = 1, and Re = 567, the maximal global Nusselt number (Nug) of 32.66 is achieved, and the highest Performance Evaluation Criteria (PEC) value of 2.33 is also obtained, which is recognized as optimal rib configuration. Meanwhile, a reduction of 0.13 in e/Dh only reduces Performance Evaluation Criteria (PEC) value by 2.19% while required pumping power can be greatly reduced by 70.23%.