In the described boiler, what is the radiant section?

• A. The Bottom Section
• B. The Top Section
• C. The Middle Section
• D. The Exterior Section

Answer: (A)

In a boiler, radiant heat transfer comes directly from the flame to the surfaces closest to it. The radiant section is the portion at the bottom of the boiler where the flame’s infrared energy is absorbed most directly by the furnace tubes. This bottom area is designed to capture radiant heat from the fire before the hot gases rise and heat the rest of the boiler mainly by convection. So the bottom section is the radiant section because it’s the zone where radiant heat transfer from the burner dominates, unlike the upper sections where convection becomes the primary mode of heat transfer.