raw · articles · ingested 2026-07-19
Simple evaporative+radiation cooling panel
Source: https://www.builditsolar.com/Experimental/RadiationCool/EvaproRad.htm
Hobbyist build documented on BuildItSolar (publication date not stated on the page).
The build
~14.25 ft² aluminum radiator, 41-gallon tank, actively pumped with a 16W submersible pump at ~0.7 GPM (≈0.05 GPM per ft² of collector).
Results
Tank temperature dropped 69°F → 49.5°F (19.5°F) over 12 hours; radiator ran 10–13°F below ambient; roughly 467 BTU/ft² of radiator cooling delivered; COP ≈ 12. Performance was best under clear, dry, low-wind conditions — the same caveat found throughout this archive’s own New Mexico data.
Why it matters for this archive
A real, tested, small-scale pumped-radiator spec (16W pump, sub-1-GPM flow) directly usable as a sizing reference for a doghouse-scale Double Play roof panel — the radiator here is only modestly larger than what a 2.5 ft³ box’s roof could carry. See Miniature thermosiphon scaling limits.