Well, if the heat were real, the company would need a heat exchanger. That is, an industrial scale ventilation system, big enough for a very large kitchens in something like a hotel or commercial bakery, with 33 of the largest stoves and ovens you can buy (100,000 btu models - 30 kW each). That calls for massive hoods inside and 4 ventilation units on the roof, each about 10 feet tall. You couldn't miss 'em!
You can't make heat disappear. Conservation of energy . . . There are no endothermic processes that could absorb that much heat, except melting tons of ice, and no one saw truckloads of ice delivered every day, so that didn't happen.
Rossi did briefly claim there was a magic endotheric process, before going on to make up the invisible heat exchanger story.
Jed,
That is classic Rossi,
He invents some steaming raft of turd story,
Waits for engineers to shoot it full of holes,
Then his posse of believers comes to his rescue with multiple possibilities of virtually impossible combinations of ridiculousness that it absolutely boggles the mind.
Rossi himself NEVER once explains, defends, suggests or indicates what really happened, he just lets the BS expand on itself until the faithful settle on the least foolish and start to really believe it.