• Nayan

MemberAug 10, 2013

## Can anyone help in understanding some concept about Solar Energy?

Hey guys, I am now and then viewing new products arriving in all types of technology based on solar power. We have railway coaches being developed in IIT Madras electrified by solar energy. On the other hand we are soon to get SOL : A solar powered laptop. This seems cool.

But my knowledge being restricted in this field, can someone explain how solar energy is converted into electricity with such high efficiency. Last time i checked on this, I knew that solar cells are too weak. we need to make an array of a number of them to harvest comparatively less energy. And here I am seeing, high power equipments running on it.

Can someone explain how did they manage to harvest so much energy with small number of cells?they are supposed to carry solar panels with them for this kind of output.
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• MemberAug 11, 2013

The maximum power which is delivered by the sun is Just 1KWh per square metre

This power is lesser to run any equipment in real time

The maximum efficiency with which we can harvest is about 15 to 20% that means We can harvest a maximum of 200Wh on the actual mid day

This power will be for charging the battery that can then be used to power your invertor for other application
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Thread moved to Electrical Engineering section.
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• MemberAug 11, 2013

Conqueror
The maximum power which is delivered by the sun is Just 1KWh per square metre

This power is lesser to run any equipment in real time

The maximum efficiency with which we can harvest is about 15 to 20% that means We can harvest a maximum of 200Wh on the actual mid day

This power will be for charging the battery that can then be used to power your invertor for other application

Agreed and I had the similar idea about figures and numbers. What I don't get is, at this amount of power, it is ok if you are able to cook food or run a simple calculator. But when it comes to laptop or railway coaches, I want to know how it is harvested in such bulk quantities. If they want to deploy it on railways, they will have to convert the whole body into solar panels comparatively.
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• MemberAug 12, 2013

Nayan Goenka
Agreed and I had the similar idea about figures and numbers. What I don't get is, at this amount of power, it is ok if you are able to cook food or run a simple calculator. But when it comes to laptop or railway coaches, I want to know how it is harvested in such bulk quantities. If they want to deploy it on railways, they will have to convert the whole body into solar panels comparatively.
Ever heard about hybrid system the system doesn't completely run on solar power it is partly run on solar power This power from solar panel is used to charge the battery powering the device
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• MemberAug 12, 2013

Conqueror
Ever heard about hybrid system the system doesn't completely run on solar power it is partly run on solar power This power from solar panel is used to charge the battery powering the device

Well i get that. Solar energy -> charger circuit -> store it in rechargeable batteries -> convert to AC using invertor -> use it whenever/wherever needed.

But this still would need a lot of solar panels to be installed on the Railway coach or laptop. Or it has some better way of capturing solar energy. My basic doubt was that.
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• MemberAug 12, 2013

There is no better way to capture the solar power if the inclination is 45 degree we can expect maximum solar power trapped by the solar panel

A lot of panels are needed but they have to laid on the surface of the coach
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• MemberAug 12, 2013

The present efficiency of solar panel is around 30 to 40 % only. But research are going on for enhancing the efficiency by using nanotechnology. In standard cell, due to impact of sunlight, electrons are released to carry electric charge and some heat. But by using nano crystals, this heat can be converted to second electron, so that the wastage of heat is avoided
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• MemberAug 12, 2013

Current solar panels have efficiency levels are rated at ~15-30%@25deg temp.
It further reduces with in increase in temperature.
There are thermal-electric panels being developed which generate electricity as wel as have a liquid running through heat collectors(like molten salt) ..it increases overall energy density of the system.
concept of using solar energy is somewhat like this..
fill a bucket from dripping tap in 1hr & den use water frm bucket in 5mins.
in this way u can pwr a equipment rated higher than panel for a limited amt of time.
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• MemberAug 19, 2013

yea it would be more better if you couple solar auto tracking with this because the angle of sun changes time to time ...
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• MemberAug 19, 2013

Solar auto tracking consumes higher power than the power effectively harvested from the solar panel during a cloudy or rainy day

We need power and a little power that can be conveniently harvested is more than enough
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• MemberAug 20, 2013

The servos used for auto track consume power & the added complexity doesnt justify the power harvested.
MPPT is electrical tracking of panel which draws max pwr available.
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• MemberAug 20, 2013

yea MPPT is the best option... considers the intensity of light in account..
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