What is Steam generator ? Steam generator is a device used to boil water to create steam. Steam generator may refer to a closed vessel in which water is heated under pressure. Steam generator can also refer to a heat exchanger in a pressurized water reactor equipped nuclear power plant. Steam generator is also used in trains to provide heat to passenger cars. Steam generator act as heat exchangers in this system. Steam generator is then condensed to water and returned to the steam generator. Reference :Wikipedia, the free encyclopedia