Thermopile Pyranometer in Solar Power Plants – Objective, Working & Advantages

Accurate solar radiation measurement is the foundation of every high-performing solar PV plant. One of the most trusted instruments for this is the Thermopile Pyranometer.

🎯 Objective

To measure global solar irradiance (W/m²) falling on the plant surface with high precision, helping operators understand actual solar resource availability and compare it with plant energy generation.

⚙️ How It Works

A thermopile consists of multiple thermocouples connected in series:

The black coated sensing surface absorbs sunlight.

This absorbed energy heats the thermopile junctions.

The temperature difference between hot and cold junctions generates a small voltage.

This voltage is proportional to the incident solar radiation.

The pyranometer outputs mV → converted to W/m² through calibration.

It measures:

Global Horizontal Irradiance (GHI)

Plane of Array (POA) Irradiance when tilted

Diffuse radiation with shading ring/disk

✅ Advantages in Solar PV Systems

High accuracy for both direct & diffuse solar radiation.

Stable long-term performance with minimal drift.

Works in all weather—clear sky, cloudy, low-light, and high-temperature conditions.

Essential for PR (Performance Ratio) & generation forecasting.

Helps identify:

Soiling losses

Module degradation

Shading issues

Mismatch between expected vs. actual output

Supports advanced analytics in SCADA systems and O&M optimization.

📌 Why It Matters

A Thermopile Pyranometer is not just a sensor—it is the benchmark instrument for evaluating plant efficiency. Better irradiance data means better decisions, higher reliability, and improved plant performance.