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Application Guide
Electric Heaters
Kilowatt-Hours to Heat Water*—Ref. 19
Quick Estimates of
Amount of Liquid
Temperature Rise °F
Wattage Requirements
ft3
Gallons
20°
40°
60°
80°
100°
120°
140°
Continued
Kilowatts to Heat in One Hour
0.66
5
0.3
0.5
0.8
1.1
1.3
1.6
1.9
1.3
10
0.5
1.1
1.6
2.1
2.7
3.2
3.7
2.0
13
0.8
1.6
2.4
3.2
4.0
4.8
5.6
Read across in table from nearest amount in
2.7
20
1.1
2.2
3.2
4.3
5.3
6.4
7.5
gallons of liquid to desired temperature rise
3.3
25
1.3
2.7
4.0
5.3
6.7
8.0
9.3
column and note kilowatts to heat in one hour.
4.0
30
1.6
3.2
4.8
6.4
8.0
9.6
12.0
For Heating Flowing Water:
5.3
40
2.1
4.0
6.4
8.5
11.0
13.0
15.0
6.7
50
2.7
5.4
8.0
10.7
13.0
16.0
19.0
kW = GPM x Temperature Rise (°F) x 0.16
8.0
60
3.3
6.4
9.6
12.8
16.0
19.0
22.0
OR
9.4
70
3.7
7.5
11.2
15.0
19.0
22.0
26.0
kW = Liters/min. x Temperature Rise (°C) x 0.076
10.7
80
4.3
8.5
13.0
17.0
21.0
26.0
30.0
12.0
90
5.0
10.0
14.5
19.0
24.0
29.0
34.0
For Heating Water in Tanks: Use equation or table.
13.4
100
5.5
11.0
16.0
21.0
27.0
32.0
37.0
kW = Gallons x Temperature Rise (°F)
16.7
125
7.0
13.0
20.0
27.0
33.0
40.0
47.0
375 x Heat-up Time (hrs)
20.0
150
8.0
16.0
24.0
32.0
40.0
48.0
56.0
OR
23.4
175
9.0
18.0
28.0
37.0
47.0
56.0
65.0
26.7
200
11.0
21.0
32.0
43.0
53.0
64.0
75.0
kW = Liters x Temperature Rise (°C)
33.7
250
13.0
27.0
40.0
53.0
67.0
80.0
93.0
790 x Heat-up Time (hrs)
40.0
300
16.0
32.0
47.0
64.0
80.0
96.0
112.0
53.4
400
21.0
43.0
64.0
85.0
107.0
128.0
149.0
66.8
500
27.0
53.0
80.0
107.0
133.0
160.0
187.0
m
e
o
n'
(D 0)
(D
1 cu. ft. = 7.49 gallons
450'
400 300
150 100
50
25 10
0 10
20 30 40 50
60 70 80 90
100 110 120 130 140 150 160 170 180 190 200
Kilowatt-Hours to Superheat Steam Ref. 20
1. Plot points on lines P, Q and S.
P represents the inlet temperature (and saturation pressure) of the system.
Q represents the liquid content of the water vapor.
S indicates the outlet temperature minus the saturated temperature.
W indicates the heat content of the water vapor.
2. Draw a straight line from P through Q to W. Read Wi.
3. Draw a straight line from P through
S to W. Read W2.
4. Required watts = Weight (lbs.) of steam/hour x (W2-W1)
Watt density is critical. Review tem­perature and velocity prior to heater selection.
Reference is 80 percent quality at 20 psig.
Q
400'
85^3
•I
I &
95-
100
%■ a
too
aF
20QÌ
f u.
\ ;
ri
3004
; (0 - 0)
—
40QE
^1
-
e 3s
500j:
l w
-
e "5
600Ì
es
700
De
350'
¡5 300'
T
"U
e
t
ra
ur 250
t
a
in
0
210-
P
t
a e H
900^
S
W
31
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