hello
you guys may find this interesting its not directly water heating but it uses useful idea !
thats the patent us2423902
and even more intresting us2261847
cheers from poland
wojsciech
you guys may find this interesting its not directly water heating but it uses useful idea !
thats the patent us2423902
and even more intresting us2261847
cheers from poland
wojsciech

, but the one thing that seems to have some legs is the sonic water heater because it has been made before and many people have seen this work.
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