The Atomic Hydrogen Furnace is a concept described by William Lyne in his book: Occult Ether Physics

It is based on Irving Langmuir's discovery of atomic hydrogen and his atomic hydrogen torch, which was apparently able to produce way more heat than the energy it took to run it.

William Lyne's concept of the atomic hydrogen furnace had a hydrogen supply from a tank but as he shows, it could very well be an electrolysis cell to create atomic hydrogen from from water.

To understand this concept, please get a copy of William Lyne's book here: Occult Ether Physics

"Occult Ether Physics: Tesla's "Ideal Flying Machine" and the Conspiracy to Conceal It, 4th revised and expanded edition, 2012 (including updates on Lyne Atomic Hydrogen Furnace). Lyne invented the Lyne Atomic Hydrogen Furnace in 1964, published plans in Occult Ether Physics in 1997. This invention has resulted in the so-called "Rossi-Focardi LENR Device" (based on his invention)."

Hopefully, this will get the conversation going so that we can create an open source project where we can see successful replications of this very important technology.