BASIC SOLAR PV TRAINING · Resistance Resistance limits the flow of electrons through the wires, like a nozzle restricts the flow of water through a pipe Smaller pipes restrict water

BASIC SOLAR PV TRAINING

1Climate Resilient Low Cost Buildings in Marsabit County Project, 2018

How is electricity generated from the

Sunlight?

SunlightPhotons

Solar Panel (photovoltaic (PV) module)

Electrons

Electricity

2

Basic solar system for a home

3

Source KEREA 2012

Parts of a solar system

4

Source KEREA 2012

Types solar panels

Source KEREA 2012

Source KEREA 2012

Types solar panels cont..

Batteries

Source KEREA 2012

Batteries cont..

Source KEREA 2012

Source KEREA 2012

Batteries cont..

Charge Controllers

Source KEREA 2012

Source KEREA 2012

Inverters

Inverters convert direct current (DC) power into alternating current (AC) power

The power stored in the batteries is in form of DC and this needs to be converted to AC to be used by electrical

appliances.

Basic concepts of electricity

Current

Voltage

Resistance

Power

Watt and Watt Hour

Ohm’s law

Power law

Alternate current (AC)

Direct current (DC)1

2

Current

Electricity flow can be compared

to water flow

Current is the quantity of

electrons flowing inside wires

(conductors)

Symbol: ‘I’ Unit: ‘A’ (ampere)

1

3

Voltage

Voltage is the electrical potential, or

the pressure that moves electrons

through the wires (conductors) and

can be compared to pressure in a

water pipe

Voltage is the electric potential

difference between two points

Symbol: ‘V’. Unit: ‘V’ (voltage)

Positive (+)

TerminalNegative (-)

Terminal

Positive (+)

Terminal (raised

button)

1

4

Resistance

Resistance limits the flow of electronsthrough the wires, like a nozzlerestricts the flow of water through apipe

Smaller pipes restrict water flow, justlike smaller wires restrict electricalflow (higher resistance)

Longer pipes also restrict water flow.Similarly, the longer the wires, thehigher the resistance

Lower resistance

Higher resistance

Higher resistance 7

Resistance

Resistance is the opposition

to the passage of an electric

current

Symbol: ‘Ω’ Unit: ‘Ohms’

16

Ohms law

Current, Voltage and Resistance

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Power

Power can be thought of as a

stream of water, which has

both pressure and flow rate

Power is derived from voltage

(V) multiplied by current (I)

P = V x I

Symbol: ‘P’ and Unit: ‘W’(watt)

1V x 4A = 4W 2V x 2A = 4W

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Electricity Summary

Current symbol: ‘I’, unit: ‘A’ (ampere)

I = V / R

Voltage symbol: ‘V’, Unit: ‘V’ (voltage)

V = I x R

Resistance symbol: ‘Ω’ and Unit: ‘Ohms’ R = V / I

Power symbol: ‘P’ and Unit: ‘Watt’ P = I x V

Energy symbol: ‘E’ and Unit: ‘Watt hour’ E = P x t

32

Power & Energy

If the 20W module is used to charge a

battery for 5 hours per day

Total energy generated per day is 20

W * 5 hours = 100 Watt-hours (Wh)

If the 60W bulb is used for 5 hours a

day

Total energy used per day is 60 W * 5

hours = 300 Watt-hours (Wh)20 W Power Generation

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Example: Solar water pumping.

Source KEREA 2012

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Source KEREA 2012

What can Solar Power do?

END

Well-done!!