In several articles and books on thermodynamics, equations describing the b
ehaviour of unsaturated moist air are available. On the other hand, to our
best knowledge, a summary of the thermodynamic functions together with all
their derivatives is lacking. Individual equations contained in the list of
equations in this article are useful for numerous applications in the held
of heat transfer and thermodynamic processes of humid air. They can also b
e applied to other examples, e.g. to construct diagrams which describe vari
ous classes of other vapours, such as of solvents. In particular, the deriv
atives yield a solid basis for error estimates of the related thermodynamic
processes. An example-describing a dew point measurement to determine the
relative humidity of moist air-is discussed. It demonstrates how the theory
can be applied by readers who are interested in applying the results to in
terpret their experimental data. (C) 1999 Elsevier Science Ltd. All rights
reserved.