If we could get enough companies to test stoves here, all that burning would warm our Winter by 10 or 20 degrees. Maybe that is what has been going on -- I know my coal usage is down about 1/3 so far this season.
That is a minature version of a water tube coil type hot water boiler. Depending on the controls it could be used as a steam boiler also. They put out an incredible amount of heat and chew up fuel like it's free. Only big draw back is that you must have a positive water circulation through the tube at all times. Any scale buildup in the tube and you restrict water flow creating a hot spot in the coil and bingo. Coil ruptures and you either have to pull the coil and replace it or try your best for a temporary repair. The tube appears to be stainless????? If so ka ching ka ching when you go to replace the coil.