Engineers Edge

Specific Enthalpy - Thermodynamic Properties

Thermodynamics Directory | Heat Transfer Directory

Specific Enthalpy

Specific enthalpy (h) is defined as h=u+Pν, where u is the specific internal energy (Btu/lbm) of the system being studied, P is the pressure of the system (lbf/ft2), and ν is the specific volume (ft3/lbm) of the system. Enthalpy is usually used in connection with an "open" system problem in thermodynamics. Enthalpy is a property of a substance, like pressure, temperature, and volume, but it cannot be measured directly.

Normally, the enthalpy of a substance is given with respect to some reference value. For example, the specific enthalpy of water or steam is given using the reference that the specific enthalpy of water is zero at .01°C and normal atmospheric pressure. The fact that the absolute value of specific enthalpy is unknown is not a problem, however, because it is the change in specific enthalpy (Δh) and not the absolute value that is important in practical problems. Steam tables include values of enthalpy as part of the information tabulated.

Contribute Article
Spider Trap

© Copyright 2000 - 2015, by Engineers Edge, LLC www.engineersedge.com
All rights reserved
Disclaimer | Feed Back | Advertising | Contact

Front Page
Engineering Store
Engineering Forum
Engineering News
Engineering Videos
Engineering Calculators
Site Directory
Engineering Jobs
GD&T Training ASME Y14.5-2009
DFM DFA Training
Advertising Center


Share |


Copyright Notice

Publishing Program