# Solar powered computer systems



## Warrigal (Aug 18, 2015)

I am interested in setting up a computer system in a village school in Papua New Guinea. I understand that solar powered systems are fairly common in parts of India where electricity is not available.

I'm exploring this idea at the moment and would appreciate any insights into what would be the necessary elements of such a system. It should allow village children access to the internet and broaden their educational experiences. It would also need to be able to be secured from robbery but that is not what I need to know first.

This site has some information and I'd be interested in your comments and suggestions for enhancements

http://www.academia.edu/5936427/Solar_Computing_Use_of_Solar_Energy_to_Run_Computer_System


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## imp (Aug 18, 2015)

Ma'am, with all due respect, the article is good, but seems "bent" more towards selling than impartial review. A few facts I offer are these: All our home PCs utilize a Power Supply, either contained within (like a "desktop"), or separate, integral with a power cord, which plugs into a wall outlet, typical set-up with a laptop computer. My own, in  use right here, has a power-cord type supply, which serves two-fold: it charges the PC's internal battery after cordless use, and it also powers the PC when in use, thereby sparing the battery. It's output is 18.5 Volts D.C., 3.5 Amperes. Knowing these things, makes one point obvious: Solar generated electric power is a "natural" for computers, well-suited since solar cells generate Direct Current, which is needed by the PC.

Here are a few drawbacks. First, computer availability will likely be desirable "24/7". The Sun don't shine 24/7 (fortunately for us!). So, the Solar Power generated during daylight must be "saved" or stored for use at such time as solar output is zero. Furthermore, computers are sensitive to input voltage changes; they want "constant voltage". Solar output will vary from near-zero (night-time) to maximum during noon day sunlight, with great variation between those limits of minimum and maximum output. So, the solar power generated is usually "stored" in the form of Chemical Energy instead of Electrical, which does not lend itself to "storage". A class of electrical devices called Capacitors have the capability of "storing" electrical energy directly, that being available for use by electrical connection to the capacitor. To my knowledge, capacitors are not yet being used for practical energy storage, but I am at the same time "behind the times" in current development aspects. This leaves us with the specter of storing our solar power in batteries, which serve as energy sources for the computers. Batteries are heavy and expensive. One "fine-tooth" decision before committing will be whether the desired solar system will be installed in an area which has _some _commercial power availability, or _no _power available at all. 


Cost: For a "grid-tie" system which provides about 800 KWH (Kilowatt-Hours) per month, about $10,000. This from: http://www.wholesalesolar.com/solar-information/solar-cost

Average lap-top PC power consumption is roughly 100 Watts. This from: https://secure.www.upenn.edu/computing/resources/category/hardware/article/computer-power-usage

Using worst-case use scenario, assuming our PC will be "On" 24/7, it will require 2.4 KWH per DAY, or, 72 KWH per MONTH. Thus, an 800 KWH solar system would be adequate to run 800/72 PCs, about 11 computers. Thus, running one computer entirely by Solar Energy, using the above mentioned solar source, would require an initial investment of about $900. Many factors here remain unanswerable, however. One is that the system mentioned is designed to supply an Alternating Current load (a home). 

A more realistic approach to cost estimating might be to use cost figures for the components themselves, solar cells, hardware, etc., then "lump in" a figure for design and construction cost, adding a profit margin, then go looking for a suitable system some company has already marketed.     imp









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## Warrigal (Aug 18, 2015)

There will be no power outlet on the wall and the system need only be used for a few hours a day. 
It in intended for use in a village school.

Battery storage is used to even out the power supply and the system needs to be able to run on DC, not AC power.

This is why I'm asking if anyone knows about this kind of system. I do know that they exist in the third world, and the cost is relatively low.


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## Falcon (Aug 18, 2015)

I saw a picture of an Indian on a stationary bicycle connected to a small generator.
He had a laptop on the handlebars and was working outdoors.

I'm pretty sure I've conferred with him when asked a company for help with something or other.

THIS, even if I've requested speaking with a person without an accent.


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## Meanderer (Aug 18, 2015)

Falcon said:


> I saw a picture of an Indian on a stationary bicycle connected to a small generator.
> He had a laptop on the handlebars and was working outdoors.
> 
> I'm pretty sure I've conferred with him when asked a company for help with something or other.
> ...


I think I talked to the same guy....he was peddling something!


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## Meanderer (Aug 18, 2015)

I have heard of solar box cookers for pasteurizing milk or water in a few hours, using only sunlight. They are made of foil-coated cardboard.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91110/


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## imp (Aug 18, 2015)

Meanderer said:


> I have heard of solar box cookers for pasteurizing milk or water in a few hours, using only sunlight.
> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91110/



One step away from a fresh-water distiller!    imp


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## Warrigal (Aug 18, 2015)

You guys are really funny, but I am serious.

Out here we had an education system for remote station children that worked on a pedal radio. 



> *SCHOOL OF THE AIR - HISTORY    *[h=3]From the early 1900's, the education of isolated children across Australia was catered for by the Correspondence Schools in the capital cities of their respective states. Lessons took days and sometimes weeks to reach their destinations and by the time the completed lessons were dispatched to their teachers, marked and returned to the children, months could have elapsed. As these children rarely had an opportunity to visit their teachers at the Correspondence School, the children inevitably completed their entire schooling without ever meeting their teacher or schoolmates.[/h] The aim of School of the Air was to bring isolated children out of the silence and give them a sense of belonging. The first "School of the Air" in Australia was established at Alice Springs on 8th June 1951. The radio network, maintained by the Royal Flying Doctor Service, was used by the school to make two-way broadcasts to the children in that area via HF Radio.
> 
> Following a visit to Central Australia, the Hon. R.J. Heffron, M.L.A, former Premier of NSW, and at the time, Minister for Education, decided that the far west of NSW should be served by a "School of the Air" similar to that operating at Alice Springs.



The idea of an internet linked computer  system to connect isolated rural children is just an extension of this older idea. Of course the equipment will have to be a bit specialised but I believe it already exists. What I need now is someone who understand just what is required and where it might be sourced.


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## tnthomas (Aug 18, 2015)

Dame Warrigal said:


> I am interested in setting up a computer system in a village school in Papua New Guinea. I understand that solar powered systems are fairly common in parts of India where electricity is not available.
> 
> I'm exploring this idea at the moment and would appreciate any insights into what would be the necessary elements of such a system. It should allow village children access to the internet and broaden their educational experiences. It would also need to be able to be secured from robbery but that is not what I need to know first.
> 
> ...



Very exciting concept, one I've been personally interested in.  The link you listed looks to covers the basics of deployment.  

Imp points out some potential financial concerns, and feasibility pitfalls.

Perhaps the folks involved in the *O*ne *L*aptop *P*er *C*hild(OLPC) might have some valuable input on the needed infastructure.

OLPC site: http://laptop.org/en/vision/index.shtml

Please keep us posted!


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## Meanderer (Aug 18, 2015)

The idea behind the Solar Box Cookers, is to free women, from spending all day gathering firewood to do this job. Also, the reflective cardboard is low-tech & inexpensive and can reach many homes and locations.


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## Warrigal (Aug 18, 2015)

Thanks for the link Tom. I'll book mark it.
I'm in the research phase of this development ATM.

There won't be a laptop per child but even one per classroom would make a big difference.
Security will be an issue. By this I mean making sure the components would be stolen or destroyed.


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