BIPV (Building-Integrated Photovoltaics) embeds solar cells directly into façade glazing units. For lobbies this means windows generate electricity while maintaining 20–50% transparency. Output: 50–120 W/m² at 8–14% module efficiency. On a 60 m² south-facing business centre façade, panels produce 25–40 kWh/day — enough to power the lobby's lighting and air conditioning. The technology is advancing rapidly: over the past 3 years BIPV module costs have fallen 35% while efficiency has risen 4 percentage points, making the solution commercially attractive.
Technology and Module Types
Thin-film CdTe (cadmium telluride) or CIGS (copper indium gallium selenide) modules are deposited on the inner laminate surface. Film thickness: 2–5 µm. Transparency: 20–50% depending on cell density. Tinting: neutral grey, bronze, blue or green.
Crystalline c-Si modules are used in opaque inserts (spandrel zones, friezes): efficiency up to 22%, output up to 200 W/m². Glazing unit: 6+12+6 mm (glass + argon + glass). Total thickness: 28–36 mm. Thermal transmittance: U = 1.0–1.4 W/(m²·K).
Energy and Economics
Estimated yield for a temperate climate: 700–900 kWh/m² per year (south façade). A 60 m² BIPV lobby: 42,000–54,000 kWh/year. At $0.15/kWh, annual saving: $6,300–$8,100. Payback period: 7–10 years at a glazing cost of $350/m².
ESG bonus: a BIPV façade lowers a building's carbon footprint and earns points towards LEED certification (up to 3 credits for renewable energy) and BREEAM. For Class A tenants, this is a selection argument.
In regions with high solar irradiance (southern Europe, Middle East), BIPV façades can achieve net-zero energy balance for the lobby zone, covering lighting, cooling and reception desk equipment entirely from the glazing output. This transforms the building envelope from a cost centre into an energy asset.
Installation and Maintenance
BIPV panels mount in standard curtain-wall systems (Schüco, Reynaers, Aluprof). Electrics: micro-inverters per panel, cabling behind the curtain wall, connection to the internal grid via an ATS board. 60 m² façade installation: 7–10 working days.
Maintenance: façade wash twice a year (standard procedure), annual visual inspection of micro-inverters. Power degradation: under 0.5% per year. Module manufacturer warranty: 25 years. Reception Space installation warranty: 5 years.