#Entropy of vaporization plus#

The fact that the absolute value of specific enthalpy is unknown is not a problem, however, because it is the change in specific enthalpy (в€†h) and not the absolute value that is important in practical problems.Д¬alculate the amount of primary coolant, which is required to evaporate 1 kg of feedwater in a typical steam generator. For example, the specific enthalpy of water or steam is given using the reference that the specific enthalpy of water is zero at 0.01вЊ and normal atmospheric pressure, where h L = 0.00 kJ/kg.

Normally, the enthalpy of a substance is given with respect to some reference value. In general, enthalpy is a property of a substance, like pressure, temperature, and volume, but it cannot be measured directly.

#Entropy of vaporization plus#

The specific enthalpy is equal to the specific internal energy of the system plus the product of pressure and specific volume. Note that the enthalpy is the thermodynamic quantity equivalent to the total heat content of a system. It equals to the total enthalpy (H) divided by the total mass (m). The specific enthalpy (h) of a substance is its enthalpy per unit mass. Engineers use the specific enthalpy in thermodynamic analysis more than the enthalpy itself. The enthalpy can be made into an intensive, or specific, variable by dividing by the mass. Enthalpy in Intensive Units вЂ“ Specific Enthalpy Extensive and intensive properties of medium in the pressurizer.