Psychrometric Formula

psychrometric formula

[¦sī·krə¦me·trik ′fȯr·myə·lə]

(thermodynamics)

The semiempirical relation giving the vapor pressure in terms of the barometer and psychrometer readings.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Psychrometric Formula

 

a relationship that permits a determination of vapor pressure from the readings of dry-bulb and wet-bulb thermometers. Mathematically, it is expressed as e = E – AP(t – t_w), where e is the vapor pressure in the air, E is the saturation vapor pressure at temperature t_w of

Figure 1. Dependence of the psychrometer constant A on the velocity of air flow past the thermometer bulb

the wet-bulb thermometer, t is the air temperature, P is the atmospheric pressure, and A is the psychrometer constant, which depends on the design of the psychrometer and, in a more direct way, on the velocity of air flow past the thermometer bulb (see Figure 1).

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.