No, I think it would not work for rice coal. And I have seen one of these up close...every part of it is sheet metal...burn pot and all.
It takes a good amount of fussing just to get the pellets to burn...inventor is located in the North West and has designed it around the Soft Wood Pellets of that region...Just the switch to our Eastern Hard Wood pellets make for timely tweaks...Coal, well that's a tall order.
According to the website;
Steel .120 wall 3.5" square tubing
That's damn thick sheet steel. The video says the primary and secondary grates are 316 stainless which I used to cut daily for about 10 years and I'm not convinced it would hold up to the heat for too long but apparently he's making it work....I guess.
And I'm awfully skeptical about the 21k Btu rating heating 2000 sf. Maybe if it never got below 50* outside but my Mark II has trouble heating that area in the dead of winter and I think it's rated around 70k Btu.
Still, I like that he's thinking. My biggest knock on pellet stoves is that they require electricity to run so they are a negative to me as a primary heat source. I'll stick with my boiler plate box.