Thermohydraulic performance of hybrid ribs pattern combining V and arc shape ribs in solar air heater

Solar energy is a limitless and ecological-friendly renewable energy source, which can be utilized for varieties of application ranging from heating/cooling, power generation, drying, and in heat-processing industries. Solar air heaters (SAHs) are among the best options for harnessing solar energy for thermal purposes like heating and drying. However, the performance of SAH is not sufficient to take into practical applications. Low performance of SAH is due to its low convective heat transfer capability because of smooth absorber plate. In this regard, an attempt has been made to enhance the heat transfer capability of SAH exploiting hybrid ribs in this paper. Hybrid rib roughness pattern incorporating to V shape ribs and arc shape ribs has been designed and tested experimentally in the SAH duct under the following range of Reynolds number (Re) from 2000 to 16,000. The various roughness patterns, i.e., arc angle (& alpha;), angle of attack (& beta;), relative V ribs position (d/w), relative rib pitch (p/e), and relative rib height (e/D), have been exploited in the range of 30o-75o, 30o-75o, 0.2-0.10, 8-10, and 0.023-0.043, respectively. As a result, Nusselt number (Nu) and friction factor (f) have been enhanced significantly. Maximum enhancement in Nu has been found as 3.08 at & alpha; = 45o, & beta; = 60o, d/w = 0.65, p/e = 10, and e/D = 0.043. Thermohydraulic performance (TP) parameters have also been evaluated for all set of parameters of hybrid ribs pattern and it found to be maximum 2.18 at & alpha; = 30o, & beta; = 60o, d/w = 1.0, p/e = 10, and e/D = 0.043.

Automated summary

This study successfully enhanced the heat transfer capability of a solar air heater (SAH) by incorporating a hybrid rib roughness pattern, leading to improved performance of SAH. Various roughness patterns were tested, and the results showed significant enhancements in Nusselt number and friction factor. Thermohydraulic performance parameters were also evaluated, and the maximum value was found for a specific set of parameters.