Honeywell Design and Application User Manual

Section 2 - Enthalpy Theory And Controllers
63-8594-02 Honeywell Economizers 24
The Psychrometric Chart
This is a psychrometric chart. To use the chart
effectively the thermodynamic properties of air
must be known. Some common terms are:
Dry Bulb Temperature
The temperature read directly on an ordinary
thermometer.
Wet Bulb Temperature
The temperature read on a thermometer
whose bulb is encased in a wet wick and with
air blown across the wick at 900 ft. per minute
(274 meters per minute). The evaporation of
the water causes the temperature to drop, this
may also be referred to as the “evaporation
effect.” When the temperature stops falling
that is the wet bulb temperature. The sling
psychrometer is a common instrument used to
determine the wet bulb temperature although
there are other methods now available.
Dry bulb and wet bulb are the two most readily
measurable variables on the chart and when
known can be used to determine all other
properties on the psychrometric chart.
40 F
4 C
50 F
10 C
60 F
16 C
70 F
21 C
80 F
27 C
90 F
32 C
100 F
38 C
110 F
43 C
120 F
49 C
35 F
2 C
45 F
7 C
55 F
13 C
65 F
18 C
75 F
24 C
85 F
29 C
95 F
35 C
105 F
41 C
115 F
46 C
F 0 9
) C 2 3 (
B L U B T E W
F 5 8
) C 9 2 (
B L U B T E W
F 0 8
) C 7 2 (
B L U B T E W
F 5 7
) C 4 2 (
B L U B T E W
F 0 6
) C 6 1 (
B L U B T E W
F 5 5
) C 3 1 (
B L U B T E W
F 0 5
) C 0 1 (
B L U B T E W
5 4
F
(
7
) C
B L U B T E W
0 4
F
(
4
) C
B L U B T E W
5 3
F
(
2
) C
B L U B T E W
H R % 0 8
H R % 0 7
H R % 0 3
H R % 0 4
H R % 0 5
H R % 0 6
H R % 0 9
H R % 0 1
H R % 0 2
H R % 0 0 1 - N O I T A R U T A S
F 0 7
) C 1 2 (
B L U B T E W
F 5 6
) C 8 1 (
B L U B T E W
DRY BULB TEMPERATURES
M25278

Honeywell Design and Application Specifications

General

Brand	Honeywell
Model	Design and Application
Category	Controller
Language	English