Vaisala HUMICAP HMP155 User's Guide download pdf (Page 82)

USER'S GUIDE____________________________________________________________________

80 _______________________________________________________________ M210912EN-C

Enthalpy:

xxTh







 5.2)00189.001.1(

(4)

The water vapor saturation pressure at temperature T

pws

is calculated over

water and over ice by using four equations (5-8). These formulas are

taken from Hyland, R.,Wexler, A.:

Formulations of the Thermodynamic

Properties of the Saturated Phases of H2O from 173.15 K to 473.15 K

Ashrae transactions 1983, Part 2A. pp. 500-513.

PWS over water:







pwsi

TCT

(5)

PWS over ice:

pws

T

(6)

where:

pws

= temperature in K

= coefficients

= 0.4931358

= -0.46094296 * 10

-2

= 0.13746454 * 10

-4

= -0.12743214 * 10

-7

Over water:













lnln100

iwsWATER

(7)

Over ice:













lnln100

iwsICE

(8)

where:

= Coefficients over water

-1

= -0.58002206 * 10

1 2 ... 77 78 79 80 81 82 83 84

Comments to this Manuals

No comments

Vaisala HUMICAP HMP155 User's Guide Page 82

Comments to this Manuals

Related products and manuals for Measuring, testing & control Vaisala HUMICAP HMP155