How would dwarves build a combined underground kiln, forge and bakery oven

Question

These dwarves are making steel tools and weapons, bricks, plates and other ceramics, as well as (and most importantly for this world) bread all underground crucially from the same structure. Any chimneys or flues can breach the surface, and don't need to be secret.

They've got 15th-17th century technology but no access to electricity. Minimal contact with the outside world (which is at a 21st century technology level), but ample supplies of coal, iron ore, clay and wheat/yeast etc. The dwarves don't want to rely on anything they can't recreate themselves so can't be dependent on trade with non-dwarves. They also don't want to rely on magic but have access to it.

Not all three industries need to be active at the same time of day. Preferably bread is made in the early morning.

I was thinking one giant chimney with the hottest forge fires on the lowest level, and then as the day goes on ceramics and later bread is put in the upper levels where it's less hot.

I don't know how feasible that is or if there's a better set up. Maybe a dragon kiln works better or something else.

Answer 1

Build your kiln over your forge and your bakery oven over that.

Forges work at extremally high temperatures thousands of degrees, exhaust air carrying that heat can be used to heat a kiln and a bakery oven easily both only work at 200 to 100 degrees at the maximum, usually colder than that. Chimney ovens are real things for a reason, even the exhaust from a normal wood fire is hot enough. There are kiln designs that already use indirect heat called ascending kilns.

kiln and forge, note the kiln heat source is separate from the firing chamber. Also note the large bellows feeding the forge.

the sequence should go forge, heat treating kiln (for steels), multi-chamber kiln, bakery oven, rising oven.

The important thing is you making them point in different directions so workspaces don't overlap, each of these need dedicated workspace, and you don't want craftsmen tripping over other craftsmen. Plus forges need huge bellows connected to the forge which takes up a lot of floorspace. Ideally you want at least two forges in your shop so one is always running, but they could be side by side and have connected exhaust. You could probably split up a circular space in a spiral of rooms and just overlap those devices, offsetting the floors a few feet. The bakery will likely end up directly over the forge. You also want to be able to direct the heat away from the kilns and ovens for cleaning and maintenance.

Smelters are huge things only used intermittently and have to be cooled and reloaded so they are useless for this and should be separate. If your really want to combine them with something combine them separately with glassworks, both operate at extremely high temperature.

As @Join pointed out you need a lot of airflow for a forge so it needs to be close to the surface with lots of ventilation. Heat is less of an issue since underground dwellings generally need heating anyway, and incoming air minimizes heat build up in the forge.

Answer 2

They can make a big dome shaped furnace, like the one in the picture, using clay bricks.

They would load it with coal, lit the fire and then after it warmed up add more coal and iron ore. After the iron ore has been smelted they could use the residual heat for firing the the pottery. In case higher temperatures were needed, they could also load more coal. Then, at the end of the shift, they could use the cooling furnace as a oven for baking bread.

This assumes they are not concerned about any intermixing between iron ores pollutants, pottery and baked products.

Alternatively, they could make a longer closed tunnel shaped furnace with three loading door on its length: they would load coal and iron ores closer to the dead end, the hot combustion fumes would move across the tunnel creating different temperature zones on the path between the combustion zone and the chimney. The intermediate zone would serve for firing pottery while the far end zone would serve for baking bread.