Either gas or electricity can heat a broiler. A broiler usually cooks food on one side at a time. Electric coils, gas, or infrared heating elements are located in the top of the broiler cavity. On the bottom is a sloping grease pan to catch extra grease. A heavy-duty broiler may be a single unit or stacked units.
Some units have drop-down doors, but most have an open front.
This open door makes this an inefficient way to get heat to food. It is used mainly for melting cheese, browning the tops of casseroles, broiling short orders, and cooking meats to the rare stage quickly. Like a conveyor oven, food is placed on a chain and carried through the cooking chamber. The chain broiler cooking chamber is much hotter than a conveyor oven. The chain becomes very hot and gives the food surface a grilled appearance.