Civil Engineering Reference
In-Depth Information
Table 19.4
(continued)
Economic evaluation
parameters
Annual energy saving Annual cost saving
Investment life Investment
Q
el
Q
th
C
pel
Q
el
C
pth
Q
th
PAYBACK
IRR
Description of case studies
Section
MWh/year TOE/year
kU/year
Year
kU
Year
%
Refrigeration plant
Replacement of absorption system
1,140
902.0
114.0
144.3
10
305
10.06
-
Heat recovery
0.0
80.7
0.0
12.9
10
20
1.55
64.00
HVAC
Recovery from exhaust air
21.7
422
2.2
67.5
10
600
9.2
1.5
Computer control
240.0
90.0
24.0
14.4
8
200
5.2
11
Lighting
Replacement of fluorescent with HF
249.3
0.0
24.9
0.0
8
160
6.4
5.1
Replacement of HF with LED
135.8
0.0
13.6
0.0
12
100
7.35
8
Heat recovery
Water/water
0.0
474.3
0.0
75.9
10
75
1.0
101
Air/air
0.0
84.0
0.0
13.4
5
25
1.9
45.5
Plant control
278.1
101.3
27.8
16.2
8
250
5.7
8
Assumptions:
C
pel
¼
0.1 kU/MWh;
C
pth
¼
0.16 kU/TOE; additional saving and costs are ignored
a
Extra cost
b
O&M cost considered
