TELKOMNIKA ISSN: 1693-6930
Optimal Design of Fuel-cell, Wind and Micro-hydro Hybrid System using Genetic …. Soedibyo 697
≤ ≤
≤ ≤
= f
V t
V if
Vf t
V r
V f
r V
t V
c V
if wt
t V
A c
V t
t V
if t
W P
ated Pr
. 3
. .
. 2
1 η
ρ
1 where ρ is air density kgm
3
, A is swept area of rotor m
2
, t is wind speed ms, η
wt
is efficiency of WTs, V
c
is cut-in speed, v
r
is rated speed, v
f
is furling speed and P
rated
is rated power of WTs. Table1. Specification of wind turbine
Rated power kW 100
Cut-in ms 3.5
Cut-out ms 25
Rated ms 12
Swept area of rotorm
2
314.16 Efficiency
30
Figure 3. Wind speed data Figure 4. Flow rate data
3.2. Micro-hydro Power
The electrical power generated by the hydro turbine can be determined using the following equation [5].
t . Q
net . g .H
hvd . ρ
hvd η
hvd P
=
2 whereH
net
is the effective head, the actual vertical drop minus this head loss. It can be calculated using the following equation [7].
1 h
f H
net H
− =
3 Meanwhile, Q
t
is the hydro turbine flow rate, theamount of water flowing through the hydro turbine. It can be calculated using the following equation [7].
=
max max
max min
min Q
t Av
Q if
Q Q
t Av
Q Q
if t
Av Q
Q t
Av Q
if t
t Q
4
50 100
150 200
250 300
1 2
3 4
5 6
7 8
9
Time hour W
in d
s p
e e
d m
s 50
100 150
200 250
300 0.5
1 1.5
2 2.5
3 3.5
4 4.5
Time hour F
lo w
r a
te m
3
s
ISSN: 1693-6930
TELKOMNIKA
Vol. 10, No. 4, December 2012 : 695–702 698
whereQ
Av
is the flow rate available to the hydro turbine m
3
s,Q
min
is the minimum flow rate of the hydro turbine m
3
s,Q
max
is the maximum flow rate of the turbine m
3
s [7]. Q
min
is the minimum flow rate, the minimum allowable flow rate through the hydroturbine; it is assumed that the hydro
turbine can operated only if the available stream flow is equal to or exceeds this minimum value. It can be calculated using the following equation [7]:
D Q
. W
t Q
min min
=
5 Q
max
is the maximum acceptable flow rate through the hydro turbine, expressed as a percentage of the turbine’s design flow rate [7]. This simulation uses this input to calculate the maximum
flow rate trough the hydro turbine, and hence the actual flow rate through the hydro turbine.
D Q
. W
t Q
max max
=
6
3.3. Electrolyzer
Basically, electrolyzer work based on the water electrolysis. A direct current is passed between two electrodes then submerged in water and decomposes into hydrogen and oxygen.
Then, the amount of hydrogen can be collected from the anode side. Usually, the hydrogen produces by the electrolyzers at a pressure around 30 bars. Also, the reactant pressures within
a Proton Exchange Membrane Fuel Cell PEMFC are around 1.2bar. For assumption, the electrolyzer is directly connected to the hydrogen tank. Transferred power from electrolyzer to
hydrogen tank can be defined as follows [5]:
el .
EL P
k EL
P η
= −
tan
7 Where
η
el
is the efficiency of electrolyzer.
3.4. Hydrogen Tank
