““Solar Energy Systems Solar Energy Systems (Photovoltaics) in (Photovoltaics) in

comparison with the comparison with the conventional Generators”conventional Generators”

Prepared by: Hassan Ahmed,System Engineer,AE Department,Welt Konnect

(Basics)(Basics)

Document # AE-KHI-PDO-0002

Scope of the PresentationScope of the PresentationReasons of the Presentation:– Being a part of the Alternative Energy Department, one

should have basic know-how about the working of the systems it deals in.

– To acquire basic knowledge about How Solar Energy System (Photovoltaic) works?

– To be able to take part or engage in conversations related to working of Solar Energy systems.

– This presentation is purely to understand the technicality of the Photovoltaic.

Why Generator:– Because we all are familiar with a conventional Generator

and it is easy to learn something by comparing it to a familiar object.

A Conventional GeneratorA Conventional Generator

So we can tell the client:“Here is your 1 KW Generator for your 1 KW Load”.

1 kW Generator

Generates 1 kW continuously

1 kW Appliance

Consumes 1 kW continuously

Fuel

The The Ideal ConditionIdeal Condition for a Solar Panel for a Solar Panel

“IF” this condition were true we would have told the client:“Here is your 1 KW Solar Panel for your 1 KW Load”.

1 kW Appliance

Consumes 1 kW continuously

90˚Mr. Sun

Generates 1 kW continuously

1 kW Solar Panel

What Actually HappensWhat Actually Happens• A Solar Panel does not generate its Peak Power through-out the day.• The Power Generation at a specific time depends on the position of

the sun at that time.

1 KW Peak Power Solar Panel

500 500

800W 800W

1 kW

EastWest

Equivalent Sun Hours (Insolation)Equivalent Sun Hours (Insolation)

1 kW Solar Panel

500

800W

1 kW

EastWest

500

800W

10 Hrs.

90˚

Insolation depends purely on the Location and season eg, Karachi has average 5.44 hrs of Insolation.

But total Energy Generated in 10hrs. = 5 kWH

A Perpendicular Sun would have Generated this Energy (5 kWH) in

5 hrs. only.

How much Solar Panels do we need for How much Solar Panels do we need for our Appliance ?our Appliance ?

• The answer is we calculate Energy per day.

1 kW Appliance

Runs 10 Hrs. per Day

1 kW * 10 Hrs. = 10 kWH per Day

So Energy consumed is,

1 KW Solar Panel

Equivalent Sun Hrs. : 5 Hrs.

So Energy generated is,1 kW * 5 Hrs. = 5 kWH per Day

Conclusion: Energy req. = 10 kWHEnergy gen. = 5 kWH

So, Number of Panels required = 2

Battery Back-up & Other AccessoriesBattery Back-up & Other Accessories

• The Energy is Generated by a Solar Panel only during day-time.

• Even during day-time, Generation is non-uniform.• However we might need to run the appliance

during night and during a cloudy day as well and at uniform power.

• For these reasons we use Batteries to store Energy and provide when required.

• We use Charge controllers and inverters to provide desired and uniform power to the appliance.

ConclusionsConclusions

• A Photovoltaic system does not generate continuous Power like a Generator.

• Photovoltaic systems are specified in terms of Energy Consumption and Generation per Day.

• Solar Panel Output depends upon the Location and Season as well.

• Batteries and other accessories are added to the system depending upon the type and usage of the load(appliances).

FormulaeFormulae

Thank YouThank You