Vaisala PTU300 - Manual (Page 206)

User's Guide _______________________________________________________________________
204 __________________________________________________________________ M210796EN-G
Mixing ratio:
w
w
P p
P
x
-
99 . 621 × =
(2)
Absolute humidity:
T
P
a
w ⋅ =
68 . 216 (3)
Enthalpy:
x x T h
⋅ + ⋅ + ⋅ − =
5 . 2 ) 00189 . 0 01 . 1 ( ) 15 . 273 (
(4)
The water vapor saturation pressure P
ws
is calculated by using two
equations (5 and 6):
∑
=
− = Θ
3
o i
i
i
T C T
(5)
where:
T = temperature in K
Ci = coefficients
C0 = 0.4931358
C1 = -0.46094296 * 10-2
C2 = 0.13746454 * 10-4
C3 = -0.12743214 * 10-7