METEOROLOGY – OLAR RADIATION CALCULATOR
Direct Normal Irradiance
A precise tool.
What is the Direct Normal Irradiance & How does it work?
Direct Normal Irradiance (DNI) is the amount of solar radiation received per unit area by a surface that is perpendicular to the sun’s rays. It is an important parameter in solar energy applications and meteorology.
The DNI can be estimated from the Global Horizontal Irradiance (GHI) and the diffuse fraction using the following formula:
DNI = frac{GHI}{1 – alpha}
alpha = diffuse fraction
Parameters
Result
β
Frequently Asked Questions
What is Direct Normal Irradiance?
Direct Normal Irradiance (DNI) is the amount of solar radiation received per unit area by a surface perpendicular to the sun’s rays.
How do I calculate DNI from GHI and diffuse fraction?
Use the formula: DNI = GHI / (1 – Ξ±), where Ξ± is the diffuse fraction.
Why is DNI important in solar energy applications?
DNI is crucial for designing and optimizing solar panels and systems, as it directly affects their efficiency and output.
What does the diffuse fraction represent?
The diffuse fraction represents the portion of sunlight that is scattered by particles in the atmosphere and reaches the surface diffusely.
Can DNI be measured directly?
Yes, DNI can be measured using a pyrheliometer, which is an instrument designed to measure solar radiation at normal incidence.
How does atmospheric conditions affect DNI?
Atmospheric conditions such as clouds, dust, and pollution can significantly reduce DNI by scattering or absorbing sunlight.
What is the unit of measurement for DNI?
DNI is typically measured in watts per square meter (W/mΒ²).
Results are for informational purposes only and do not constitute professional advice.