Herrmidifier Load Calculator User Manual
Page 11
L o a d C a l c u l a t i o n G u i d e
L o a d C a l c u l a t i o n G u i d e
11
w w w. h e r r m i d i f i e r- h v a c . c o m
SECTION III LOAD CALCULATIONS
Knowing that controlled humidification is needed is the first
step toward increasing productivity and cutting losses. The
second, and most important step, is to accurately deter-
mine the amount of moisture required to be added to the air
to reach the target R.H. level. A humidification project that
starts out with good intentions can fall flat because the de-
mand load was not calculated accurately and too little or too
much humidification equipment was installed. Following is a
simple, accurate guideline for determining your MAXIMUM
HUMIDIFICATION DEMAND LOAD. Help with calculating
this can be obtained by returning form I/C DI-5 to Herrmidi-
fier.
The Psychrometric Chart
All humidification calculations involve knowing the maxi-
mum amount of moisture a given quantity of air can hold at
saturation (100% R.H.), and being able, by calculations, to
compare this with the amount of moisture present and that
which is desired in that air. The amount of moisture in the air
is measured in grains per cubic foot. This figure is used in
calculations to eventually arrive at a demand load, in pounds
per hour, for the area to be humidified. The following Table
2-A shows the grains of moisture per cubic foot of air at spe-
cific temperature.
Table 2-A
°Fahrenheit
Grains
°Fahrenheit
Grains
-10
.29
52
4.41
-5
.37
53
4.56
0
.48
54
4.72
5
.61
55
4.89
10
.78
56
5.06
15
.99
57
5.23
20
1.24
58
5.41
25
1.56
59
5.60
30
1.95
60
5.80
31
2.04
61
6.00
32
2.13
62
6.20
33
2.21
63
6.41
34
2.29
64
6.62
35
2.38
65
6.85
36
2.47
66
7.07
37
2.56
67
7.31
38
2.66
68
7.57
39
2.76
69
7.80
40
2.86
70
8.10
41
2.97
71
8.32
42
3.08
72
8.59
43
3.20
73
8.87
44
3.32
74
9.15
45
3.44
75
9.45
46
3.56
76
9.75
47
3.69
77
10.06
48
3.83
78
10.40
49
3.97
79
10.80
50
4.11
80
11.04
51
4.26
81
11.40
82
11.75
107
24.26
83
12.11
108
24.93
84
12.49
109
25.62
85
12.87
110
26.34
86
13.27
111
27.07
87
13.67
112
27.81
88
14.08
113
28.57
89
14.51
114
29.34
90
14.94
115
30.13
91
15.39
120
34.38
92
15.84
125
39.13
93
16.31
130
44.41
94
16.79
135
50.30
95
17.28
140
56.81
96
17.80
145
64.04
97
18.31
150
72.00
98
18.85
155
80.77
99
19.39
160
90.43
100
19.95
165
101.00
101
20.52
170
112.60
102
21.11
175
125.40
103
21.71
180
139.20
104
22.32
185
154.30
105
22.95
190
170.70
106
23.60
195
188.60
There are basically three (3) humidification load factors and
two (2) humidification reduction factors:
HEATING LOAD: For desired R.H. at maximum indoor tem-
perature maintained when outdoor temperature is at mini-
mum heating design level.
COOLING LOAD: To replace moisture removed by conden-
sation from cooling process -- air conditioning and/or refrig-
eration.
PRODUCT LOAD: To condition product to final desired Re-
gain when received under other conditions. This load could
be plus or minus.
PROCESS REDUCTION: Moisture vapors emitted by pro-
cesses decrease humidification load.
PEOPLE REDUCTION: People give off 0.2 lbs. per hour
when seated; 0.9 lbs. per hour when active, thereby de-
creasing humidification load. We shall take a more, in depth,
look at these factors in this section.