Civil Engineering Reference
In-Depth Information
17.9
Practical Examples
An example of computer application to energy management in a site requires a
great many details and data on process and facility equipment and on the hardware
and software chosen.
There are many kinds of software and hardware available on the market, which
make many levels of control possible.
Example
A computerized system to control a factory's facilities.
In order to give a general example of application in industry, in what follows the
factory is represented by its electric and thermal model, as detailed in Table
17.10
,
which gives estimates of energy saving in facilities on the basis of practical
experience.
Other advantages, such as reduction of working hours for plant maintenance and
operation, will certainly increase the economic advantages of the control system
(see also Example 2 in Sect.
13.7
), but they are not here considered.
Table 17.10
Energy saving due to computer control of facilities
Estimated
energy saving
(%)
Average
absorbed
power kW
Annual
consumption
kWh/year
Working
hours h/year
(kWh/year)
Electric model
Air-compressor plant
250
5,000
1,250,000
7
87,500
Pump plant
75
5,000
375,000
15
56,250
HVAC refrigerating plant
500
1,750
875,000
7.5
65,625
HVAC auxiliaries
100
3,500
350,000
12.5
43,750
Lighting
100
5,000
500,000
5
25,000
Process
800
5,000
4,000,000
0
0
Others
250
5,000
1,250,000
0
0
Total
2,075
8,600,000
278,125
c
¼
a
b
e
¼
c
d/100
a
b
d
Thermal model
(%)
(TOE/year)
Process boiler plant
7,500
5,000
3,225
3
96.751
HVAC boiler plant
1,000
1,750
150.5
3
4.515
Total
8,500
3,375.5
101.266
a
b
c (*)
d
e
¼
c
d/100
10
3
) where LHV of oil is 41,860 kJ/kg
Notes (*) c
¼
a
b
3,600/(41,860
