Numerical investigation of a PV-assisted hybrid ventilation strategy for monitor roofs

Weak wind conditions can substantially reduce the ventilation capacity of monitor-roof systems, especially in hot regions. To address this limitation, the present study examines a roof-assisted hybrid ventilation concept in which PV-supplied fans are combined with a conventional monitor roof and assessed through numerical flow simulations. The reference case consisted of a 1.2 m × 1.2 m monitor roof with a 0.3 m eave extension. A 20-fan array was placed along the roof opening, and the simulations compared two fan scales (0.3×0.3 m, 0.6×0.6 m) together with two discharge velocities (0.5 and 2 m/s). Outdoor wind conditions were represented by a power-law profile with an exponent of 0.143, and the reference wind speed at 10 m height ranged from 0.01 to 3 m/s. The results show that PV-powered fan assistance can effectively enhance ventilation under stagnant or low-wind conditions, when natural driving forces are insufficient. However, the contribution of the fans decreases as outdoor wind speed increases and wind-driven ventilation becomes dominant. Among the investigated cases, larger fans operated at higher outlet velocity showed the most stable and substantial improvement. The study demonstrates that integrating PV-powered fans with monitor roofs is a feasible approach for strengthening ventilation performance and environmental adaptability in industrial buildings.