One of the key features of the Sunmeter PRO (Reference Cell Sensor) is the integration of photovoltaic-grade microprismatic glass, the same type of glass used in commercial photovoltaic modules.
Unlike conventional Si_irradiance sensors that use flat, high-transparency glass, Soluzione Solare integrates photovoltaic-grade microprismatic glass to better replicate the optical behavior of PV modules.
The Sunmeter PRO sensors( PV Reference Cell) are calibrated with a measurement uncertainty below 2%, and their irradiance readings closely match the actual energy production of a photovoltaic module under real operating conditions. This makes the Sunmeter PRO particularly suitable for accurate PV system performance monitoring.
Photovoltaic glass features a microstructured “orange peel” texture composed of concave and convex geometric elements. This surface structure increases light trapping and improves photon capture, especially when sunlight is not perpendicular to the module plane, such as during morning, evening, winter periods, or low solar altitude conditions.
The microprismatic structure enhances the probability that incident solar radiation reaches the reference cell, reducing reflection losses and improving angular response. Additionally, the glass is coated with an anti-reflective layer with a refractive index optimized between air and glass, further minimizing surface reflection.
In contrast, conventional flat glass, despite its high transparency, exhibits higher reflectance at incidence angles greater than approximately 20°, which can lead to an underestimation of irradiance in real-world PV operating conditions.
By replicating the optical behavior of photovoltaic modules, the Sunmeter PRO provides a more realistic measurement of plane-of-array irradiance compared to sensors using standard flat glass.
When compared to pyranometers, which use hemispherical dome quartz glass, the difference in terms of reflectance and spectral transparency becomes even greater, moving further away from the optical behavior of photovoltaic modules.
Therefore, using an irradiance sensor with photovoltaic-grade glass improves the accuracy of performance ratio measurements, since the irradiance sensor behaves more similarly to a photovoltaic module under operating conditions.
The Sunmeter PRO complies with IEC EN 61215 (paragraphs 10, 11, and 12) and IEC EN 61724-1 Class A requirements.
The sensor provides a digital RS-485 output and is compatible with major datalogger and inverter platforms.
