heating water with 1/2 - 50' copper coil in boiling water open pot

I have managed to plum 1/2" copper pipe into my existing baseboard radiator system using a circulator pump @ 5.3 gallons per minute . This is attached to a pot of water { 20 gal. - I think } that sits on top of my wood stove . We boil the water and circulate through the coil . Temperature output ranges 130 - 140 degrees F ; depending on cycling interval . I also have a rocket stove set-up that provides the same function . That is able to reach 160 degree output ; but , as we know - that requires constant loading . Just like a steam engine - rolling down the tracks .

Both methods are open top pots where no pressure builds ....

Looking for a way to improve temperature output using my wood stove . That requires substantially less loading times ....

any ideas - please

thanks , c.j.

Since the sides of the pot are presumably open to air and shedding heat that way, I would suggest insulating the sides. Also, a way of transferring more of the stove's heat to the pot would help... maybe thick aluminum sheet pieces in an L from the rest of the stove top extending up the sides of the pot, with insulation above (not touching) the stove top and enclosing the pot. An old aluminum cookie sheet cut up might work.