[dremd]

It would work, but I have 2 concerns
1) Capacity Would heat up very quickly, but would run out of steam quickly as well.
2) Pressure House hold water is around 50 psi, radiator pressure is around 14 psi Not sure if it would be up to the job.

I've determined that my tank is simply from a 40 gallon gas water heater, they either cut the insulation / burner out, or bought one un-assembled.

I don't yet have the 2nd pane of glass mounted, but I think it will help retin the heat through the night / clouds.