Search results
Results From The WOW.Com Content Network
Latent heat (also known as ... The large value of the enthalpy of condensation of water vapor is the reason that steam is a far more effective heating medium than ...
Enthalpies of melting and boiling for pure elements versus temperatures of transition, demonstrating Trouton's rule. In thermodynamics, the enthalpy of fusion of a substance, also known as (latent) heat of fusion, is the change in its enthalpy resulting from providing energy, typically heat, to a specific quantity of the substance to change its state from a solid to a liquid, at constant pressure.
If wet steam is heated further, the droplets evaporate, and at a high enough temperature (which depends on the pressure) all of the water evaporates, the system is in vapor–liquid equilibrium, [7] and it becomes saturated steam. Saturated steam is advantageous in heat transfer due to the high latent heat of vaporization.
The specific enthalpy of fusion (more commonly known as latent heat) of water is 333.55 kJ/kg at 0 °C: the same amount of energy is required to melt ice as to warm ice from −160 °C up to its melting point or to heat the same amount of water by about 80 °C. Of common substances, only that of ammonia is higher.
Data in the table above is given for water–steam equilibria at various temperatures over the entire temperature range at which liquid water can exist. Pressure of the equilibrium is given in the second column in kPa. The third column is the heat content of each gram of the liquid phase relative to water at 0 °C.
Boiling water creating steam in an electric kettle. Steam's capacity to transfer heat is also used in the home: for cooking vegetables, steam cleaning of fabric, carpets and flooring, and for heating buildings. In each case, water is heated in a boiler, and the steam carries the energy to a target object.
A condenser is designed to transfer heat from a working fluid (e.g. water in a steam power plant) to a secondary fluid or the surrounding air. The condenser relies on the efficient heat transfer that occurs during phase changes, in this case during the condensation of a vapor into a liquid. The vapor typically enters the condenser at a ...
For example, to heat water from 25 °C to steam at 250 °C at 1 atm requires 2869 kJ/kg. To heat water at 25 °C to liquid water at 250 °C at 5 MPa requires only 976 kJ/kg. It is also possible to recover much of the heat (say 75%) from superheated water, and therefore energy use for superheated water extraction is less than one sixth that ...