Artificial enhancer for small-scale solar air heater—A comprehensive review

CFD Analysis of the Heat Transfer and Fluid Flow Characteristics Using the Rectangular Rib Attached to the Fin Surface in a Solar Air Heater

“…A comparison was made between the simulated results and those obtained from Gnielinski correlation and Dittus-Boelter empirical correlation, both of which have been widely employed in related research [8,[23][24][25]. The Gnielinski and Dittus-Boelter empirical correlations are expressed as Equations ( 1) and (2).…”

“…A further advantage of the SAH is its low manufacturing, operating, and maintenance costs due to its simple design compared to other solar thermal systems [1]. However, since air has a low thermal conductivity, the absorber is unable to effectively transfer heat to flowing air, resulting in low thermal efficiency of the system [2]. To overcome this issue, many researchers have employed various techniques.…”

Parametric Optimization of Solar Air Heaters Having Hemispherical Protrusion Roughness in the V-Notch Pattern on the Absorber Plate: A Metaheuristics Optimization Approach

“…A solar air heater heats ambient air by trapping solar thermal energy, but it has low thermal performance due to the formation of a laminar sub-layer over a heated absorber plate [2]. Various techniques, such as packed beds, ribs, fins, dimples, and protrusion, are used to improve the thermohydraulic performance by breaking the laminar sub-layer [3][4][5]. Artificial roughness, such as dimples and protrusions, has become the most popular technique [6][7][8][9].…”

Heat Transfer Augmentation and Friction Factor Due to the Arrangement of Rectangular Turbulators in a Finned Air Channel of a Solar Air Heater

“…In addition, its simple design provides some merits, such as low manufacturing cost and minimal required maintenance [1]. However, a major drawback of SAHs is their low thermal efficiency, which is a consequence of the low thermal conductivity of air [2]. Therefore, many researchers have attempted to increase the heat transfer from the absorber plate of an SAH to the flowing fluid.…”

“…Their research concluded that the proposed apex-up ribs provided better thermal performance than the conventional apex-down ribs. Including these studies, various types of turbulator, such as rectangular rib [16], wedge-shaped rib [17], hyperbolic [18], multistaggered W-shape rib [19], quarter-circular rib [20], sinusoidal protrusion [21], Multi-V rib [22], discrete multiple inclined baffle [23], and conical protrusion have been investigated so far, and more detailed information can be found in relevant review articles [2,3,24].…”