If the plan is to dump from bags into the outside barrel then auger it inside, it doesn't seem like there will be a chance for the coal to dry enough. Especially in NH (sorry NJ and MD guys, but this fellow is in a different climate), I'd expect a lot of freeze-up problems. I've kept bulk coal outside in gravity wagons and it flows fine as long as it's bought far enough ahead of time to dry well. Dumping fresh bags outside might work best if the outside hopper was more like a box against the house that was insulated on all sides except the side facing the house (i.e., so that heat from the house would keep the frost out of the coal). Otherwise buying and drying ahead of time seems essential.