The Smaller the Better: Designing Solar Energy Harvesting ...
Solar System Designing
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Transcript of Solar System Designing
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No. of Fans = 4 Wattage of one fan= 100 watt
Total fan wattage = 400 watt
No. of lights=4 Wattage of one fan= 25 watt Total lights wattage= 100 watt
Total wattage= fan + lights= 400+100= 500 watt
Load Calculation
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We will calculate daily watt-hour usage of each
appliance.
This is done by multiplying each appliance wattage by no. of hours usedeach day
For example if we use each appliance 4 hours daily, then watt hourcalculation is done by following way:
Total wattage = 500 watt
No. of hours used each day = 4Watt hour = 500 * 4
= 2000 watt-hours.
Watt-Hour Calculation
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For batter battery usage, we should rely on 80 % capacity
of the battery.
We can also assume that battery efficiency is about 80 %
So, dividing total watt-hours by battery efficiency , we
will get
Total Battery capacity = Total watt hour / batteryefficiency
Total Battery Capacity
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Total Battery Capacity = 2000 / 0.8
= 2500 watt-hour
Cont.
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Batteries are rated in ampere-hours(Ah).
Battery bank voltages are 2, 4, 6 ,12 volts
If we want a battery bank of 48volts , we will connect 4batteries of 12 volts in series i-e
12x4 = 48 V
Size of battery bank can be calculated by dividing totalbattery capacity to battery bank voltage.
Size of Battery Bank(Ah)
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Size of battery ( Ah) = Total battery capacity/
Battery bank voltage
= 2500 watt-hour / 12 V
= 209 Ah
Cont.
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To arrange 209 Ah battery is somehow difficult so we use series
of batteries to meet 209 ampere rating.
For example if we are using 45Ah battery of 12 V then totalnumber of batteries required are given by following formula:
No. of Batteries = Size of Battery(Ah) / 45 Ah.= 209 Ah / 45 Ah.
~ 4.6 or 5
These batteries are connected in parallel to increase current (Ah).When batteries are connected in series , voltage(V) is increased.
No. Of Batteries Required
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For Example we are using solar panels each having 60
watt power . So how much solar panels are required tomeet our requirements .
No. of solar panels required is calculated by dividingdaily watt-hours with solar panel wattage times averagesunshine.
Let us assume that average sunshine is 6 hours.
No. Of Solar Panels
Required
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So,
No. of Panels = 2000 / ( 60 x 6 )
~ 5.5 = 6 panels
Cont.
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