Analyzing impact of ground reflections and wind speed on the temperature distribution in a building-integrated photovoltaic (BIPV) facade

Building-integrated photovoltaics (BIPV) enable solar energy generation in urban environments but face challenges due to non-optimal orientation, restricted airflow, and shading. These factors affect irradiance and module temperature, leading to power mismatch across façades. This study investigates vertical irradiance and temperature variations in a test setup of eight vertically mounted mini PV modules (0.15–3 m height) at DTU Risø, Denmark, under varying ground albedo conditions: grass (0.25), white tarp (0.5), and black tarp (0.05). Measurements under clear and cloudy skies show higher irradiance at lower module positions with grass and white ground covers, and the trend reverses with black cover. Ray-tracing simulations confirm the trends for the lower and higher local albedo.For a clear-sky day in April irradiance and temperature differences of 20W/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 3°C are observed between the highest and second lowest module. A rough estimate using the Sandia model indicates that only max 20% of the temperature difference can be explained by the irradiance differences on this day. No clear link was found between measured wind speed and temperature differences between the modules. Results highlight the importance of accounting for local albedo and airflow effects in vertical BIPV design. Ongoing work includes assessing the impact of wind direction, nearby objects, and seasonal changes.