The dew point temperature of a sample of air with water vapor pressure pv is the temperature to which it must be cooled to become fully saturated.
where phi is the
Relative Humidity variable. See
Saturation State for the definition of saturation pressure
psat as a function of temperature. See also
Saturation Pressure for the definition of the variable
psat.
The equivalent temperature is obtained by adiabatically condensing all the water vapor of a sample of air with initial vapor pressure pv. In this process, the latent heat decrease due to total removal of the vapor is balanced by a increase of the sensible heat and temperature.
where phi is the
Relative Humidity, and
γTeq (SI unit: Pa/K) is the psychrometer constant, defined in
Ref. 1 by:
where p is the total pressure,
Cp, a is the heat capacity at constant pressure of dry air at temperature
T,
Lv is the latent heat of evaporation at temperature
T (see
Latent Heat of Evaporation), and
Ma and
Mv are the molar mass of dry air and water vapor, respectively.
See also Saturation Pressure for the definition of the variable
psat.
The wet bulb temperature is also represented on Figure 3-1. It is obtained by adiabatically reaching saturation state for a sample of air with initial water vapor pressure
pv. In this process, the latent heat increase due to evaporation is balanced by a decrease of the sensible heat and temperature. It is not available as a predefined variable, but it can be approximated by solving the following equation:
where T is the temperature. See
Functions for the definition of the function
fpsat.
where T is the temperature. See
Functions for the definition of the function
Lv.