what is a boiler

A boiler is a closed vessel that heats fluid, usually water, to be used in various processes or heating applications. The source of heat for a boiler is combustion of fuels such as wood, coal, oil, or natural gas. Electric steam boilers use resistance- or immersion-type heating elements, while nuclear fission is also used as a heat source for generating steam. Boilers can be used to heat a home using steam and radiant heat techniques, and they rely on the thermostat to tell them when to start heating the water within their system. There are two main types of boilers: firetube and watertube boilers. Firetube boilers have combustion gases pass inside boiler tubes, and heat is transferred to water between the tubes and the outer shell. Watertube boilers, on the other hand, have boiler water pass through the tubes while the exhaust gases remain in the shell side, passing over the tube surfaces. Boilers are used in various industries, including the food industry and beer brewing process.