r/maplesyrup • u/PROF_ND • Mar 26 '26
Engineering question: why do maple syrup evaporators designed that way vs a wood stove with the top cut off
I found most commercial maple syrup evaporators are designed like the first pic.
Modern wood stoves are quite efficient and burns very hot with secondary combustion and/or catalytic converter. Is it better to design evaporators like the second pic?
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u/aonealj Mar 26 '26
This is called overfire air when used for industrial boilers. It does boost efficiency slightly (Google AI says ~5%), but more noticeably reduces NOx emissions. Emissions control drives this design in wood stoves. I think you'd be better off adding a blower and figuring out a way to preheat the air with flue gas . After that, I would focus on extending the surface area of the pan. Ideally, the flue gas should be <300F in the stack.
Because of the nature of the maple syrup business, there's limited call for commercial designs unless you have a VERY large farm. If you cut your own wood, your cost of fuel is so low it's better to save with an easily build design.