This tutorial will be of a fully automatic furnace, where you simply put fuel and the things to be smelted into 2 chests and collect the finished items from another. I have researched lots of different forms of this design, but this is by far the most compact and efficient one I could find.
This build is very resource friendly, as it uses no redstone.
All you will need is a furnace, 3 chests and 3 hoppers.
Step 2: Top Chest
Start off by placing a chest on top of a 4 block high structure; the blocks are only there to have something to put the chest on.
Now put another chest at the bottom as shown in pic 2; shift click a hopper on top of that chest and the furnace on top of that.
Step 3: Hopper 2
Place the second hopper on the left side of the furnace with a chest running down into it.
To finish off, place the last hopper running into the furnace as shown in pics 3 and 4.
Step 4: Using It.
To use it, put up to a maximum of 35 stacks of fuel in the left chest ( '35' assuming you have a single chest), 35 stacks of food, ore etc in the top chest, and you will get 35 stacks of finished items in the bottom chest.
I hope everyone has enjoyed this build and finds it of use in your minecraft survival world.
Good things about it:
It is very fast and easy to make.
Different kinds of fuel can be put in at the same time.
No fuel is ever wasted due to the chest and hopper system.
Bad things about it
You don't get any exp.
It takes about 6 and a quarter hours to cook 35 stacks of items.
I will be posting an industrial size smelter based on this design when I get the time, until then I hope this design helps you out.