The Solar Spectrum

 

I get email questions about what part of the solar spectrum has what percentage of the solar energy, so I thought the chart below might be helpful -- the rough distribution is:

 

Near IR  -- 49%

Visible  --  46%

UV         --  5%

The most common question is "Will the UV protective coating used to protect most plastic glazing materials from degradation significantly reduce the heat gain for a collector?"  -- looks like the answer is no.

 

 

 

This is a chart from an ORNL presentation on IR reflective paints...

 

 

Gary February 27, 2010