solar thermal collector efficiency in rain
 

Can anyone point me to data on the effect, if any, of turbulent water flow, ie. rain, on solar thermal collector efficiency?

Thanks,

Does it rain while its sunny much in Vancouver Island? No offense, but the question seems kind of strange.

I'm more interested in what wavelenght(s), of those that would normally pass through the glazing into the collector, would be reflected or refracted by the water, independent of light intensity.

I wouldn't consider it an issue. If you have sun on a panel its going to heat up and evaporate that water very quickly.

The water will suck the heat out of the panel but of course it is just temporary. It will be gone very soon after the sun comes out