JJUSM Solar Pump Co. Providing water to your lands at a lower cost than Diesel!
Also called a Linear current booster, which is basically a variable dc to fixed dc converter. Its job is to maximize current at the max voltage point. It boosts the current from the modules at lower insolation
levels to provide starting current, while during normal
operation, it maintains the voltage at Vmp.
C. Pump Controller
Pump Specifications
(Refer curve 70 from data sheet) Nominal Voltage 36 V Voltage at Pump 45 V Current at Pump 24.2 A Power at Pump 1089 W Min PV Array Power 1416 W Max Flow Rate 12.5 m3/h (55
gpm) In this case, for 30 ft dynamic
head, flow rate is 12.5 m3/h
D. Solar Water Pump
Problem: The average cost to pump water for a
Pakistani farmer over a period of 25 years is
$443,383 .
The modules are connected in
series & parallel configuration to
match the pump controller’s
requirements.
B. Solar Panels
The number of panels is calculated by doing a case study for the year of 2010, by taking in the data for average monthly insolation, precipi-tation and water requirement of the field over a year.
Number of panels required = 14
Array Wpeak = 2800W
This type of module chosen because it is assembled in Pakistan and
therefore cheaper. The solar cells(Q-cell) is manufactured in Germany
•These modules were preferred over thin film modules due to
high cost of importing these panels.
•Single axis manual adjustment is included in the mounting
Specifications
SUNPUMPS Model : PCB-220
Max Open Circuit Voltage 250V
Max Load Current 25 A
Max Load Power 1200 W
Efficiency 99%
Cost $ 500
2 pumps have been used, each with its own pump controller.
The calculation for the number of pumps re-quired is based on the load profile (water re-quirement over a period of one year) The pump manufacturer estimation of 1.3 times the power required for the pump has been inde-pendently verified. Number of pumps required = 2
Specifications Capacity of tank 6000 m3 (1.5 million gallons) Dimensions (m) = 26 x 26 x 9 Height above ground level 0.5 m Dynamic Head 9.5 m
E. Tank
F. Land
Kharif season -> May 1st to Oct 15th – Rice Rabi season -> Dec 15th to Mar 15th – Wheat Peak water requirement occurs on May 1, when 6 cm of standing water above the ground level is required throughout the field ar-ea. Precipitation data is used to calculate approx. rainfall and get the adjusted demand of water required from the tank. Load pro-file has a resolution of 5 days. In this way, 72 data points are ana-lyzed for the year.
The water requirement of the agricul-tural land of 10 acre area is the load profile for the study, shown in the graph. Operation is started from march 15, or alternatively Oct 15.
Performance Analysis
The size of the tank, water demand, Pump flow rate have been optimized us-ing linear programming (MATLAB).
Results have been verified in Excel. (file attached)
Tolerance limits have also been tested. Two cases have been considered in this regard. According to the results the sys-tem can meet all targets with 97 % avail-ability.
Also, if average rainfall is reduced by 6%. Our water pumping would still fulfill all demand for the entire 72 data points each year.
Graphs show how the tank is best used to cater for such high demand at the begin-ning of the rice crop.
In this way, cost has been reduced by
building a larger tank rather than in-
stalling more pumps/larger solar array.
After the first year, the storage from the tank in the 2nd year onwards provides even more water security. Also about 4200 cubic meters of extra water (once tank reaches capacity of 6000 cubic meters) can be distributed to neighbors every year.
System Design
Minimize (x)
subject to
Water (tank)*x ≥Water (demand)
400≤Vtank ≥6000
where,
x – number of modules
Ps – Power output of one module (kW)
Pload – Power drawn by the pump mo-tor to suffice the water require-ment of the field (kW)
Vtank – Volume of tank (m3) x is obtained to be 14 for the case study considered
Number of pumps is determined to be 2 as the maximum power output is around 2.16 kW, and the rating of each pump is 1.08 kW.
The optimization study was also done to look at the degradation of panels over the years, varia-bility in insolation and precipitation levels. The proposed sizing is still valid for 97% availa-bility and 6% reduction in average rainfall. The cell degradation is compensated by the ex-cess water generation over years. From the se-cond year, we can supply around 4000 m3 of wa-ter every year to negate the effect of cell perfor-
Based on NOCT value from the mod-ule datasheet, the power coefficient and the average temperature, the ar-ray power has been calculated for each month. The overall array size in chosen for assured operating level against high temperature, dust, manufacturer tolerances and degradation factors.
- Graph shows solar array power lost due to temperature
Solar Array Sizing
Exact monthly insolation data for the location obtained by us-ing the Geospatial Toolkit, developed by NREL for Pakistan.
Solar Insolation in Kwh/m2/day
About 25% of Pakistan's total land
area is under cultivation and it has
the world’s largest irrigation system
Save $41,4896
using Solar
Power
•This is the primary expenditure for the farmers
compared to the relatively low costs for the raw
materials, fertilizers etc.
• Cost of diesel is around 51 cents/kWh in
Pakistan, which is increased by 20 % from 2010.
•Pakistan is currently facing an energy shortage
of 3600MW.
SOLAR COST
For Pakistan Assumed: Inflation Rate: 10 % Interest Rate: 2% Controllers and Pump life Cycles : 15 Years Cost of Tanks, Wires, and manual Tracking : $2500 The power demand of Pump: $2800 Cost Rate of Panel: 1.5$/W Installation Cost: $2500 Maintenance Cost: $75 per year after 1st year The start-up cost of this system : $10968 The LCC is the sum of all terms : $28487 Operating hours per year : 1686 hours Power : 2.16kW Total kWh prod by panels per year : 3641.76 kWh Total kWh prod by panels for 25 years : 91044 kWh The LCOE is:
DIESEL COST
For Pakistan Assumed: Interest Rate: 7% Controllers and Pump life Cycles : 10 Years Cost of Tanks, Wires, and etc : $2500 The power demand of Pump: $2800 Cost Rate of Diesel a Year: $12000 Installation Cost including BOS : $2000 Maintenance Cost: $100 per year after 1st year
The start-up cost of this system : $5100 The LCC is the sum of all terms : $443,383 Operating hours per year : 1686 hours Total kWh prod : 33046 kWh Total kWh prod : 826150 kWh The LCOE is:
For Pakistan Assumed: Inflation Rate: 10 % Interest Rate: 2% Controllers and Pump life Cycles : 15 Years Cost of Tanks, Wires, and manual Tracking : $2500 The power demand of Pump: $2800 Cost Rate of Panel: 1.5$/W Installation Cost: $2500 Maintenance Cost: $75 per year after 1st year
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