Chesty tested it and summoned a fire elemental. Chesty is now the owner of this item.
It is 18 inches across (diameter) with a tripod that holds it at 3 feet high. As per the DMG, it takes 1 round to light it, I’d add, IF it’s already set up. It takes 1 round to set it up and add wood/charcoal. For encumbrance, it is 15 pounds with both the brazier and tripod. Both are required for the magic to work.