A boiler's a closed vessel in which water or other fluid's heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications. Overview Applications Boilers have many applications. They can be used in stationary applications to provide heat, hot water, or steam for domestic use, or in generators and they can be used in applications to provide steam for locomotion in applications such as trains, ships, and boats. Using a boiler's a way to transfer stored… (More on Boiler)