What is the Difference Between a Pyranometer and a Pyrheliometer?
A pyranometer measures total solar radiation and a pyrheliometer measures direct solar radiation. Both are used to measure solar radiation but for different purposes and under different conditions.
A pyranometer is a device that measures the total amount of solar radiation (both direct and diffuse) that reaches the surface of the earth, including the radiation reflected by the sky and surrounding surfaces. A pyranometer is designed to detect radiation in the wavelength range of 0.3 to 3 micrometers, and typically has a wide field of view, allowing it to measure radiation from the entire sky.
A pyrheliometer, on the other hand, is specifically designed to measure the amount of direct solar radiation that reaches the surface of the earth. It is a highly accurate instrument that can measure the intensity of the sun’s radiation, even in extreme weather conditions. A pyrheliometer usually has a narrow field of view, typically less than 1 degree, and is usually placed on a tracker that follows the sun’s movement, ensuring that the sensor is always pointing towards the sun.