I am a little concerned about the heat resistance of the PLA. Temps can get quite high in full sun. I think a high temp PLA or an alternate type of plastic would be more warp resistant. I had a 3D-print quad in a car for a day and the arms were totally deformed after.

The efficiency is not great as the water in the smaller collection bottle also evaporates, condenses and returns. Not sure how to shade that...

Using a damp cloth wrapped on the top section creates shade and evaporative cooling to occur, boosting the condensation rate.