'Coals' in the Bible

Now the servants and the officers were standing there , having made a fire of coals; for it was cold; and they were warming themselves: and Peter also was with them, standing and warming himself.

So when they got out upon the land, they see a fire of coals there, and fish laid thereon, and bread.

But if thine enemy hunger, feed him; if he thirst, give him to drink: for in so doing thou shalt heap coals of fire upon his head.