28 x 30 thermosiphon box, scrap 2 x 4 frame, salvaged
double pane window sash. Absorber = 1/4" plywood wrapped
with aluminum flashing sprayed barbecue black (smells
remarkably similar to Kingsford briquettes).
No sun to test, substituted a 500 watt halogen work lamp.
Shop temp = 60 F. Plate temperature after 5 minutes
at 1 ft distance from lamp read 140, air temperature
110, using a quick read oven thermometer.
To put that in practical terms, a fender washer tied
to another string and lowered into the hot spot
became too painful to hold in less than 3 minutes.
Should be even more interesting tomorrow, with