Photovoltaic module with an integrated ventilation structure for passive cooling and as a fire barrier for effective BIPV systems

• Ventilation structure can be integrated with photovoltaic module level. • Analyze air flow behavior through visualization by experiments and simulations. • Verified the passive cooling effect in ventilated air gap through dropping 11 ∼ 13 °C. • Controlling and changing air-flow velocity and path through the inner structure. • Geometry structure can provide passive cooling, support and barrier to flame. Demand for PV installations as components in buildings is increasing rapidly to achieve the goal of 100 % renewable energy. However, a significant factor for effective building-integrated PVs (BIPVs) is PV cells’ temperature under operating conditions. The operating temperature of PVs in normal climates is 60 °C, and PV cells’ efficiency decreases 0.4–0.45 % for every 1 °C increase in temperature according to their temperature coefficient. Thus, under operating conditions, the efficiency is decreased by 15 % from the indicated efficiency value corresponding to the standard test condition (STC) of 25 °C. To lower a cell’s operating temperature, a ventilation air gap can provide passive cooling through a buoyancy force in the inner air–gap space. However, in the situation of a fire, flame, smoke, and toxic gases are spread rapidly through the chimney effect in an inner ventilated air gap. Analyzing and controlling air flow within an air gap is important to enable passive cooling while also providing a barrier function for hazard cases. We conducted an analysis of air flow through experiments and simulations and suggested integrating a structural air gap into PV cells to control the air flow path and velocity. We verified that introducing a geometric structure into the inner air–gap space in a PV cell induced passive cooling, leading to a temperature decrease of 11–13 °C compared with the operating temperature of a cell without a ventilation-integrated structure. We also confirmed the barrier function by turbulence formed near the geometric structure in a high-speed inlet air flow.