Basic Boiler Design

Function

• The University of Rochester’s website reprints Hero’s transcript, which describes the workings of his early boiler. He used hot coals to heat water, which produced steam. The steam rose in tubes within a large cylinder until it emerged with force. Its expulsion provided a way to generate and harness power to operate different systems. This first-century boiler design is still representative of modern boiler design, although newer types of boilers offer more design variations and applications.

Types

• Firetube boilers contain tubes that are immersed in water. A fuel source heats air that is channeled through the tubes, which heat the water. The heated water forms steam, which produces energy. Watertube boilers heat air in furnaces that contain water-filled tubes. As the water within the tubes is heated, steam is produced that generates energy. Some water heaters use solar boiler technology. Metal plates absorb heat energy from the sun, which is transferred to an antifreeze solution that circulates throughout pipes. Pipes run through the boiler, where they heat water.

Fuel

• Different fuels can be used to fire boilers. Propane is available to most homeowners, although its expense may be greater than other fuel sources. Where natural gas is available, it is a less-expensive fuel source. Oil is the fuel commonly used in the Northeast where natural gas is unavailable, or for users at ends of the natural gas pipeline where costs are high. According to the U.S. Department of Energy, biodiesel fuels are newer sources of fuel that burn cleaner and reduce dependence on fossil fuels.

Caution

• Carbon monoxide is a colorless, odorless gas produced as a by-product of combustion. If boilers are not properly vented, or if exhaust chimneys are not sealed properly, carbon monoxide gas poses a health hazard. High levels of gas can cause heart problems, brain damage, or death in extreme cases. Because of its potential danger, some states, including Massachusetts, require carbon-monoxide detectors in all homes with equipment that burns fossil fuels, such as furnaces and boilers.