Civil Engineering Reference
In-Depth Information
Table 17 Solar charge controller
Battery
voltage (V)
Maximum power
of the PVs (W)
Maximum voltage
of the PVs (V
DC
)
Max. charging current
to the batteries (A)
12
1,000
80
65
24
2,000
150
48
4,000
150
outdoor conditions (sunlight, temperature, etc.) to which it must adapt. According
to the battery voltage V
cc
= 48 V, its selection involves choosing:
input voltage V >48V,
input power in solar charge controller higher than maximum power of the PV
panel at maximum voltage,
maximum charging current to the batteries I =65A.
Then, from the available products in the market (Table
17
) are chosen the solar
charge controller [
10
] with 65 A and 150 V
DC
.
D. Cogeneration unit
For sizing the CHP unit, using the Eq.
14
in Chap.
“
”
and taking from the Table
12
, the value of the speci
c energy in the
month with the biggest load of the CHP unit was obtained P
CHP
¼
5
:
65 kW, where:
daily time of operation was chosen t
oper
¼
5 h in correlation with the estimated time
for battery recharging (Table
18
in Chap.
“
”
). After that, was chosen from the market a CHP unit with nominal power
P
CHP
n
¼
es the relation: P
CHP
n
P
CHP
. Combined heat and power
unit with Stirling engine chosen [
11
] has the following characteristics:
9 kW that satis
V-stirling engine, alpha: 2-cylinder;
Displacement: 160 cm
3
;
Operating gas: Helium;
Maximum operating pressure: 150 bar;
Work rated speed: 1,500 rpm;
Produced electrical power: 2
-
9kW(3
×
380/50 Hz);
Produced thermal power: 8
-
26 kW;
Overall ef
ciency: 92
-
96 % for 50
-
100 % load;
Electrical ef
ciency: 22
-
24.5 % for 50
-
100 % load;
Power to heat ratio: 0.34;
Cooling water temperature 65
°
C;
2m
3
/h.
Flow rate in the outer system 1
-
E. Inverters
Inverters connect the batteries to the electrical appliances and convert DC voltage to
AC voltage at 50 Hz. Also, they should allow the CHP unit to supply residential
consumers and also to load the batteries.
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