pvperfsolar performance modeling

Reference

API field

Spectral correction

How the sky's spectrum changes the module output

What it is

The spectral correction adjusts the module output for the colour of the sunlight, which shifts with the height of the sun and the water vapour in the air. This section switches it on or off, gives optional coefficients and an air-mass cap. The Lee and Panchula formula needs a precipitable water column in the weather file, or a relative humidity column from which precipitable water is estimated with the ambient temperature (Gueymard 1994). The Weather tab says which of the two the loaded file carries.

Typical values and how to get it

Leave the mode on automatic. The correction matters most for cadmium telluride, whose output rises with the water vapour in the air: it gains in humid climates and can lose in dry ones. Crystalline silicon changes much less.

References

  1. Lee & Panchula 2016, Spectral correction for photovoltaic module performance based on air mass and precipitable water, IEEE 43rd Photovoltaic Specialists Conference
  2. Gueymard 1994, Analysis of monthly average atmospheric precipitable water and turbidity in Canada and northern United States, Solar Energy 53(1) 57–71

API

spectral