A pyranometer is a device designed to measure solar irradiance. Solar irradiance is the power per unit area received from sun in the form of electromagnetic radiation in a given location. To select the ideal pyranometer for your specific application, it is important to know the various types of pyranometers available in the market today. There are mainly three types of pyranometers: Thermopile Pyranometer, Photodiode Pyranometers and PV Pyranometers.
What is a Thermopile Pyranometer?
A pyranometer is usually equipped with a thermopile sensor that detects both direct and diffuse radiation. This device plays a crucial role in many fields such as meteorology, climatology, solar energy research, and environmental monitoring.
The design of a thermopile pyranometer typically features a glass dome that allows sunlight to enter from all sides. Inside, the thermopile converts thermal energy into an electrical signal, which is then processed to provide precise readings of irradiance in Watts per square meter (W/m²). The thermopile pyranometer measures the global solar radiation with a wave length range of 300 nm to 2800 nm.
What is a Photodiode Pyranometer?
Photodiode pyranometers use semiconductor materials to directly convert light into an electrical signal. They are known of their cheap price comparing to thermopile model. In the other hand, they are not sensitive especially to low irradiance levels. These instruments are beneficial for applications where a high accuracy is not required. The photodiode pyranometer measures shortwave solar radiation with a wave length range of 400 nm to 1100 nm.
What is a PV Pyranometer?
A PV Pyranometer or a reference cell irradiance sensor uses a monocrystalline silicon solar cell, which generates an electric current when exposed to light. This current is converted into millivolts (mV) via a shunt resistor located on the back of the cell. The Irradiance Sensor includes an electronic card designed to calculate solar irradiance values in W/m², with built-in temperature compensation for enhanced accuracy. The calibrated sensor is installed in the Plane of Array (POA) to precisely measure POA irradiance levels. The PV Pyranometer measures irradiance relevant to a specific PV technology with a wave length range of 400nm to 1200nm.
How to Choose the Correct Pyranometer?
When selecting a photovoltaic irradiance pyranometer, understanding the key specifications and features is crucial to ensure optimal performance and reliability in your applications.
1. Photovoltaic Application:
The Pyranometer with the closest features as the solar panels is the PV Pyranometer. Representing a small panel with similar spectral range as the PV panels, the PV Pyranometer is the recommended model to be used to calculate the Performance Ration of the PV Plants. PV Pyranometers can be used either to measure the POA Irradiance, the Horizontal Irradiance as well as the Albedo for Bifacial applications.
2. Meteorological Application:
The ability of a pyranometer to accurately measure solar irradiance across different wavelengths is an essential feature. A pyranometer with a flat spectral response will provide reliable readings for meteorological applications, as it captures both direct and diffuse irradiance effectively. Thus, Thermopile Pyranometer is the chosen type for this kind of applications.
3. Agriculture Application:
In agricultural applications, pyranometers assist in optimizing crop growth and management. By measuring solar radiation levels, farmers can make informed decisions about irrigation, planting schedules, and crop selection. This data supports precision agriculture, which aims to maximize yields while minimizing resource use. As this kind of applications doesn’t require a high precision Pyranometers, usually Photodiode Pyranometers are used.
SEVEN Pyranometers
SEVEN offers different models of PV Pyranometers and Thermopile Pyranometers. Modbus RTU and Analog options are available for both types. In the other hand, one of the main criteria to choose the Pyranometer models is its classification as per the standard IEC61724-1:2021. SEVEN produces both Class A & Class B of Thermopile and PV Pyranometers. You can check the datasheets of SEVEN Pyranometer as well as SEVEN Irradiance Sensor for more technical details. Another advantage of choosing SEVEN pyranometers is their global recalibration capability as you will be able to recalibrate SEVEN Pyranometers in any PV laboratory worldwide without the need to send them back to the factory thanks to SEVEN user-friendly configuration tool.
