Forced-Air Jet Misalignment at a Photovoltaic Chimney Outlet: Impacts on Heat Transfer and Indoor Airflow

In solar chimneys, heat released by the absorber plate warms the air, enabling natural ventilation driven by thermal buoyancy. However, such systems are often prone to reverse flow phenomena, which reduce the effectiveness of air renewal. To address this limitation, a photovoltaic (PV) chimney is proposed. This active yet autonomous ventilation system features walls comprising a glass surface and a PV panel connected to an extractor fan at the chimney outlet. The PV panel replaces the conventional absorber by simultaneously providing heat to warm the air and generating electricity to drive forced extraction. The present study quantifies the impact of forced air jet misalignment at the chimney outlet on system performance, with particular attention to the onset of reverse flow and recirculation patterns. Here, misalignment is defined as the deviation of the jet orientation from the chimney axis. The physical phenomena are modeled using the governing equations for laminar forced convection, solved numerically via the finite volume method. Simulations are performed with a Fortran-based computational code for a fixed Reynolds number of Re = 50, while varying the jet orientation angle from 0˚ to 66˚ relative to the chimney axis. The results indicate that increasing jet misalignment promotes the formation of secondary flow structures, notably recirculation zones and reverse flow within the system. Consequently, both the heat transfer rate between the PV panel and the air and the airflow rate decrease as the forced jet deviates from the chimney axis.