https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/8799681
An experimental solar heating panel being tested at New Mexico State University, Las Cruces.
This is a Thomason type where water trickles down blackened, corrugated metal plates under insulating glass. A through collector at the bottom collects heated water for circulation, 04/1974. Photographer: Norton, Boyd. Original public domain image from Flickr
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