How is heat generated?

Answer 1

When water is heated, there is a relation between temperature and pressure at which the water and steam are in equilibrium. This applies up to 374 degC at which the corresponding pressure is 222 bar abs or 3220 psi abs. Beyond this temperature liquid water cannot exist and the steam is said to be supercritical.

At any temperature between 100 degC and 374 degC there will therefore be a pressure at which steam is just formed and this is said to be dry saturated steam. It is saturated because if the temperature drops even slightly at the same pressure, steam will condense. If at this same pressure the steam is further heated, it is said to be superheated because it is at a temperature higher than dry saturated steam would be. Superheated steam is desirable for use in steam turbines, because it prevents formation of water droplets as the steam is expanded through the turbine-the droplets could damage the turbine blades.

In the supercritical region above 374 degC steam will always exist whatever the pressure, so the concept of superheat does not apply here.

Answer 2

Heat is generated through the transfer of energy from one object to another, typically due to the movement of atoms and molecules within the object. This movement creates friction and causes an increase in temperature, resulting in the generation of heat.