DESIGN OF PV SYSTEM FOR WATER PUMP:
The overall
design can be divided into five steps as given below:
STEP1:
Determine the amount of water required per day (as per the
considerations).
STEP
2: Determine the total dynamic head (TDH) for
water pumping.
STEP
3: Determine the hydraulic energy required per day
(Watt-hour/day) to pump the required amount of water
STEP
4:
Determine the solar radiation available at given location (in terms of
equivalent of peak sunshine radiation (1000W/m3) hours for which
solar pv module is characterised)
STEP
5: Determine the size and number of PV modules
required, which pump is used, and the pump rating taking into account the motor
efficiency and other losses)
6.2 CALCULATIONS:
Amount
of water pumped per day=2.2m3/day
Total
vertical lift = 2m
Water
density = 1000kg/m3
Acceleration
due to gravity = g= 9.8m/s2
Solar
PV module used = 10Wp
Operating
factor = 0.75
Pump
efficiency = 30% or 0.30
Mismatch
factor = 0.85 (if MPPT is used then it is 1)
STEP
1: Determine the total daily water requirement
Daily water requirement = 2.2m3/day
STEP
2: Determine total dynamic head
Total vertical lift =
2 m
Frictional losses =
5% of Total Vertical Lift
=2*0.05
=0.1m
Total dynamic head = 2+0.1 =2.1m
STEP
3: Determine hydraulic energy required per day:
Hydraulic energy required to raise
water level:
=
Mass *g *TDH
=
(1000 kg/m3)(2.2m3/day)(9.8m/s2)*2.1
=
12.57Wh/day
STEP
4: Determine solar radiation data:
=
6h/day (Actual day length is longer)
STEP
5: Determine the number of PV panels and pump size:
= 12.57 / 6
= 2.095W
0.3*0.85
Operating factor
= 8.21
/ 0.75 = 10.9W
No
of solar panels required of 10wattpower each:
=
10.9 / 10
=
1.09 = 1 Solar Panels of 10Wp
6.3 SAMPLE CALCULATION:
To
draw 25000 litres of water every day from depth of 10m:
Data
required for calculations is as follows:
Amount
of water to be pumped per day = 25000 l = 25m3/day
Total
vertical lift=12m (5m elevation, 5m standing water level, 2m drawdown)
Water
density = 1000kg/m3
Acceleration
due to gravity= g=9.8m/s2
Solar
PV module used = 75Wp
Operating
factor = 0.75(PV panels, in general, don’t operate at their rated peak
power)
Pump
efficiency =30% or 0.30
Mismatch
factor = 0.85
STEP
1: Determine the total daily water requirement
Daily water requirement (as stated in the problem)
=
25m3/day
STEP
2: Determine total dynamic head
Total vertical lift =12m
Frictional losses =5%
of total vertical lift
=
12 * 0.05 = 0.6m
Total dynamic head = 12+0.6 =12.6m
STEP
3: Determine hydraulic energy required per day:
Hydraulic energy required to raise
water level:
=
Mass *g *TDH
=
(1000 kg/m3)(25m3/day)(9.8m/s2)*12.6
=
857.5 Wh/day
STEP
4: Determine solar radiation data:
=
6h/day (actual day length is longer)
STEP
5: Determine the number of PV panels and pump size:
= 857.5 / 6
= 142.9 W
Operating factor
= 560
/ 0.75 = 747.3W
No
of solar panels required of 75wattpower each:
=
747.3 / 75
=
9.96 = 10 Solar Panels of 75Wp
Table 6.1: PANELS REQUIREMENT:
|
Sl.NO
|
Water Required(m3)
|
Head(m)
|
Panels required
|
|
1
|
2.2
|
2
|
1 panel of 10Wp
|
|
2
|
10
|
5
|
2 panels of 75Wp
|
|
3
|
17
|
8
|
5 panels of 75 Wp
|
|
4
|
25
|
10
|
10 panels of 75Wp
|
|
5
|
35
|
17
|
20panels of 75Wp
|
Table
6.2: COMPONENT PRICES OF PRESENT STUDY PUMP:
|
SL NO
|
NAME OF COMPONENT
|
QUANTITY
|
SPECIFICATIONS
|
COST (INR)
|
|||
|
1
|
WATER PUMP
|
1
|
19 W
|
1500
|
|||
|
2
|
BATTERIES
|
1
|
12 Volts, 60
A.H
|
2500
|
|||
|
3
|
MOISTURE SENSOR
|
1
|
|
1700
|
|||
|
4
|
SOLAR PANEL
|
1
|
10 W, 12 V
|
2800
|
|||
|
5
|
INVERTER
|
1
|
|
5000
|
|||
|
|
TOTAL
|
|
|
13500
|
|||
Table
6.3: PUMP SPECIFICATIONS:
|
Pump
Type
(HP)
|
Voltage
(V)
|
Max Head (m)
|
Power rate
(W)
|
Max
Discharge
(Q) (l/d)
|
Pump Diameter(D)
|
Recommend-ended panel capacity
(Wp)
|
Max land (acres)
|
|
0.5
|
220
|
30
|
1500
|
3000
|
100mm
|
500
|
1.2
|
|
1.00
|
220
|
57
|
1500
|
11300
|
100mm
|
1000
|
2
|
|
2.00
|
220
|
86
|
1500
|
22712
|
100mm
|
2000
|
4.5
|
|
3.00
|
220
|
110
|
1500
|
26497
|
100mm
|
3000
|
5
|
|
5.00
|
220
|
135
|
1500
|
45424
|
100mm
|
5000
|
9
|
|
7.5
|
220
|
156
|
1500
|
75367
|
100mm
|
7500
|
12
|
|
10.00
|
220
|
160
|
1500
|
90325
|
100mm
|
10000
|
16
|
|
15.00
|
220
|
166
|
1500
|
143235
|
100mm
|
15000
|
28
|
Table
6.4: COST ESTIMATION OF DIFFERENT CAPACITY PUMPS
|
Sl.No
|
Description
|
Quantity
Requirements
|
Cost estimation of each component(INR)
|
Total cost estimation (INR)
|
|
1
|
Requirements for 0.5 HP
a)Solar Panels
0.5KWp
b) MPPT
c)Cables,
inverter cum battery
d)Waterpump
e) Installation
|
1 NO
1 NO
1 NO
|
40000
18000
5000
3500
1500
|
68000
|
|
2
|
Requirements for 1.0 HP
a)Solar Panels
1.0KWp
b) MPPT
c)Cables,
inverter cum battery
d)Water pump
e)Installation
|
1 NO
1 NO
1 NO
|
80000
35000
10000
8000
2000
|
135000
|
|
3
|
Requirements for 2.0 HP
a)Solar Panels
2.0 KWp
b) MPPT
c)Cables,
inverter cum battery
d)Water pump
e)Installation
|
1 NO
1 NO
1 NO
|
160000
50000
15000
13000
2000
|
240000
|
|
4
|
Requirements for 3.0 HP
a)Solar Panels
3.0 KWp
b) MPPT
c)Cables,
inverter cum battery
d)Water pump
e) Installation
|
1 NO
1 NO
1 NO
|
240000
64000
20000
16000
2000
|
342000
|
|
5
|
Requirements for 5.0 HP
a)Solar Panels
5.0 KWp
b) MPPT
c)Cables,
inverter cum battery
d)Water pump
e) Installation
|
1 NO
1 NO
1 NO
|
400000
80000
25000
26000
3000
|
533000
|
Table 6.5: COMPARISION BETWEEN
ELECTRIC AND SOLAR POWER:
|
|
ELECTRIC POWER
|
SOLAR PANEL
|
|
LIFE
|
________
|
12 YEARS
|
|
INITIAL COST
|
Rs. 6000 (Initial electric line connection cost)
|
Rs. 68000 (Setup cost for 0.5 HP)
|
|
MAINTAINENCE/
MONTHLY COST
|
684/month(present)
2880/month( after 10years app)
|
1440/month(present)
1800/month(after 10years app)
|
|
EXTRA INVESTMENT
|
--------
|
3500/4years (for battery)
|
|
ELECTRIC UNIT
|
FOR 1 UNIT(APPROXIMATE COST) (INR)
|
FOR 180UNITS(1MONTH) (INR)
|
|
PRESENT ELECTRIC POWER UNIT COST
|
3.8
|
684
|
|
AFTER 10 YEARS
|
16 (approximately)
|
2880
|
|
PRESENT SOLAR POWER UNIT COST
|
8
|
1440
|
|
AFTER 10 YEARS
|
10 (approximately)
|
1800
|
Current and Voltage readings:
Solar panel output:
Voltage
= 21.0 V
Current
= 0.38 A
Charge controller output:
Voltage
= 20.3 V
Current
= 0.21A
We
know that solar panel output is equal to charge controller input. Charge
controller output is battery inlet. We get standard output from battery to the
pmp.
From
the above considerations we understand that though the initial cost of solar
power appliances is high we can have a long life time of about 12 years. We
also have less maintenance cost when compared with the grid power.
In long run, solar
panel generated power is comparatively better as there is scope of profit in
unit cost and mostly important, it is a renewable type of energy which will
save the fuel for the future.
The cost of a unit
power is Rs. 3.8 at present, so for one month we get approximately Rs. 684. Due
to shortage of fuels in future the cost of unit price may raise upto Rs 16/unit(approximately).
Similarly the present cost of unit solar power from the grid is Rs 8/unit. So
then we get approximately Rs 1440/month. After 10years it may raise only upto
Rs 10/month. This raise is very low due to the wide availability of solar
power. But we need to change battery for every 4-5 years. So when compared to
long run it is well suited as the fuel price and electric grid price will rise
in future.
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