They are saying it "blocks 80%" of the sunlight.
This diagram/pic, of the shows it reflecting 'solar energy'
My theory is, absorption and re-radiation as radiant heat is going be limited.
Since the material is plastic-like, it's not going to work real well (as an absorber)
and it can only hold so much. If it could continuously absorb energy,
it would melt down pretty quickly..
So, it must be reflecting most of the energy, somehow.
I'll have to look at the material outside in the sun, if it looks shiny, then we'll know.
If it doesn't look shiny, it will be interesting to see what kind of temperatures it runs at..