Abstract
Existing performance enhancement strategies for solar chimneys often require large installation space or complex structures and offer limited flexibility in ventilation control. To address these limitations, this study proposes a simple and practical louvre-shaped vortex generator for improving heat transfer and the performance of buoyancy-driven passive ventilation. A two-dimensional numerical model is adopted to examine the effects of louvre attack angle and location under different Rayleigh numbers ( Ra ). A baseline analysis shows that a louvre-integrated solar chimney with a louvre attack angle of 60 ° yields substantially higher ventilation rates than the conventional configuration, with 110–180% improvements of Air Change per Hour ( ACH ) over the Ra range of 7 × 10 10 to 2.8 × 10 12 . The performance improvement is due to vortex-induced unsteadiness in the wake of the louvre, which redistributes turbulent energy and enhances thermal homogenization across the chimney width. A parametric analysis has identified an optimal configuration with a 45 ° inclined louvre placed at the horizontal centreline and one quarter of the chimney-height from the inlet, achieving a maximum ACH improvement of 227% relative to the conventional design without the louvre. The ventilation performance gain resulting from the louvre is shown to be highly sensitive to local flow conditions, diminishing if the louvre is positioned too close to the absorber or too far from the inlet.
Abstract by the authors, reproduced under the CC BY 4.0 licence. Original publication via the link below.