I thought I would share this with everyone here, I don't remember where I found it but it was a downloaded-able PDF. It's a really great catalog from 1897 with Anthracite and Bituminous coal gravity "octopus" furnaces. Has prices, specs, even how to calculate your heating needs by cubic inches as apposed to square feet. They even have models with domestic hot water "coils." Pretty advanced for that time. Well worth looking through and reading. There are a lot of protocols that haven't changed.
I actually always thought it would be great to find one of these and put a big blower and conversion stoker in it. The heat exchangers are pretty massive and look well designed and I would think with some modification you could make one pretty efficient and get some serious heat output.
Enjoy!
