Definition
Diffuse Horizontal Irradiance (DHI) is the diffuse component of solar irradiance on a horizontal surface, in W/m². Sum of DHI plus direct beam (projected onto horizontal) = GHI.
Key Takeaways
- DHI = diffuse irradiance on horizontal surface.
- GHI = DNI projected + DHI.
- Higher DHI fraction in cloudy climates.
- Standard hourly data source for PVsyst.
- Critical for cloudy-climate solar yield modeling.
Frequently Asked Questions
2 commonly searched questions about DHI (Diffuse Horizontal Irradiance).
What is DHI?
Diffuse Horizontal Irradiance — scattered solar radiation on a horizontal surface. Component of GHI: GHI = DNI × cos(zenith) + DHI.
Where is DHI data found?
Meteonorm, NSRDB, Solargis publish hourly DHI alongside GHI and DNI for solar simulation.
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