Environmental Engineering Reference
In-Depth Information
TABLE 7.6
Variables and Properties Contributing to Heat Loss
through Cylindrical Insulated Tank
Symbol
Variable
Unit
Value
Q
Heat loss
kW
0.581
K
Coefficient of
Conduction
W/mK
0.035
L
Cylinder length
m
5
T
s
Surface temperature
C
100
T
a
Ambient temperature
C
0
R
1
Tank radius
m
2.5
R
2
Insulation radius
m
3
h
t
Radius and conversion
coefficient
W/m
2
K
15
Source:
Brumleve, T.D. 1974. Sensible Heat Storage in
Liquids, Sandia Laboratories Energy Report, SLL-
73-0263. Livermore, CA
TABLE 7.7
Monetary Value of Insulating Cylindrical Tank
Insulation
Thickness
(m)
Insulation
Volume
(m
3
)
Costof
HeatLoss
($/Year)
Payback
Time
(Years)
HeatLoss
(kW)
Insulation
Cost($)
R2
18.85
0
2.5
0.00
0
6,935
Infinite
2.428
0.1
2.6
8.01
2,648
893
3
1.321
0.2
2.7
16.34
5,400
486
11
0.917
0.3
2.8
24.98
8,256
337
24
0.708
0.4
2.9
33.93
11,215
260
43
0.581
0.5
3
43.20
14,279
214
67
Source:
Brumleve, T.D. 1974. Sensible Heat Storage in Liquids, Sandia Laboratories
Energy Report, SLL-73-0263. Livermore, CA
$16,000
$14,000
$12,000
$10,000
$8,000
$6,000
$4,000
$2,000
$0
0.6
0.5
Insulation Cost ($)
Cost of Heat Loss ($/yr)
Insulation ickness (m)
0.4
0.3
0.2
0.1
0
0
5
10
15
20
Heat Loss (kW)
FIGURE 7.7
A plot of cylindrical tank heat loss versus insulation thickness shows the value of insulation.
