C472 If You Can't Buy the Technology Just Buy It

"That is to say, when the first stove produces hot air, the second stove heats the exhaust that is being pumped out..."

Leonardo thought about it.

"That's right, master!"

Old Frederick immediately replied, "After the hot air in the furnace is heated by the exhaust air, it can directly exceed 600 degrees."

This way, it can greatly conserve energy and increase the efficiency of steelmaking