Thanks, Jeremy,
I was, in fact, worried about coil flow...it does make more sense to keep cooler water at the bottom!
If I were to use Geoff Lawton's design per his youtube video (link below), and if I kept the coil horizontal as his is, would the thermal siphon still function?
https://www.youtube.com/watch?v=1oDpmmsqHwQ&t=628s
There's a diagram at 10:31 position.
That is to say, if I still elevated my tank above a horizontal coil and used an open hot out line flowing back up and over the rim of the tank, would the hot water still siphon as effectively along a horizontal coil?
Here's a drawing:
Also, because Geoff's system is essentially a "double boiler," is it safe to assume the water therein will not flash to steam? In a system where the coil makes direct contact with the barrel, is there any chance of it flashing to steam beyond the speed at which hot water can be propelled out of an open-ended coil outlet?
I should probably make a miniature, too, to see what works best
Thanks!
Brian