A study of panel ridges effect on heat transfer and pressure drop in a ventilation duct

CFD simulations were conducted to assess turbulent forced convection heat transfer and pressure drop through a ventilation channel using a stack of panels with different ridge configurations containing Phase Change Material (PCM). First, an experimental rig using an existing commercial panel provided by a PCM manufacturer validates the model simulated in Ansys FLUENT. After that, 3D simulations with different designs were tested until the optimum configuration in terms of heat transfer and pressure drop was achieved. The optimum design by geometry and performance was drawn in 2D and a parametric analysis was performed by varying the spacing between ridges, height and ridge radius to identify difference in heat transfer performance. For both experiment and simulation, the flow rate in terms of Reynolds number based on the inlet hydraulic diameter of the channel ranged from 7200 to 21600. When compared with a flat and existing commercial panel, results show that the inclusion of ridges increase the Nusselt Number by 68 and 93% respectively at a Reynolds number of 21600. At a Reynolds number of 18736, the Nusselt number of the optimum panel is enhanced by 64 and 111% when compared to the flat and existing commercial panel, respectively. This panel was then taken forward to allow further refinements which include changes in panel thickness and number of panels per module. After more than 200 different panel designs and airflows simulations, a new design is proposed which reduces the number of panels per module from 9 to 6, thus reducing production costs but keeping nearly the same heat flux and pressure drop as the existing commercial panel. When 7 panels are used, it is possible to hold 13.68% more material with an increased pressure drop 3.36 times higher than the existing commercial panel (176.80 against 52.69 Pa) at a Reynolds number of 18736.