Moist Air Properties

Reference data and engineering information about moist air properties for air psychrometrics applications.

moistairpropertiesData Table

Overview

Engineering reference data for Moist Air Properties in air psychrometrics.

Key Formulas

Humidity Ratio

$\omega = 0.622 \frac{P_v}{P_a}$

Mass of water vapor per mass of dry air.

Relative Humidity

$\phi = \frac{P_v}{P_{vs}} \times 100\%$

Ratio of actual to saturation vapor pressure.

Wet Bulb Temperature

$T_{wb} = T_{db} - \frac{P_{vs} - P_v}{\gamma}$

Temperature measured by wet-bulb thermometer.

Enthalpy of Moist Air

$h = c_p T + \omega h_g$

Sensible + latent heat per unit mass of dry air.

Variables

Symbol	Description	Unit
$\omega$	Humidity ratio	kg/kg
$\phi$	Relative humidity	%
$P_v$	Vapor pressure	Pa
$P_{vs}$	Saturation vapor pressure	Pa
$T_{db}$	Dry bulb temperature	°C
$T_{wb}$	Wet bulb temperature	°C

Data Table

26 rows

Temperature / Saturation Pressure (Pa) / Humidity ratio at Saturation (kgH2O/kgdry air) / Specific Volume / Specific Enthalpy / Specific Entropy(J/K.kgdry air) data
col0
oC
-40
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85

Source: engineeringtoolbox.com

References

Original Source

Source: engineeringtoolbox.com