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Edward et al,<br>
<br>
I have send this info before to one fellow that was interested in this
issue. If you need more info or data, please ask.<br>
<br>
<u><b>Water</b></u>: there is HUGE difference in water availability. I
have work for mining companies from the 3,500 meters to the 5,000
meters here. There are villages were the creeks becomes a whole river
during 4 to 5 months and then get just very very small amount of water
for the rest of the year... (less water than what you get from your
shower)... the difference is so big that sometimes I have to design
"recirculating" systems to provide water for trout factories (that are
located WERE they should have never been located... but... it is a
"good neighbor" policy that mining companies have here). Distance
from the "water source" is another problem (easier to solve, we can use
some cabling to reach the batteries... but it is a factor to be taken
in account).<br>
<br>
<u><b>Wind</b></u>: Altitude doesn't comes with the wind. You need to
be 30 meters over the soil surface (if you have your feet in soil that
is at 3,500 or 4,000 meters altitude... you need to put a "tower" and
get 9 meters more! then we mount the "turbine/rotor/alternator" at the
top of the tower... (add the cost of the tower to the budget...) ... no
free lunch... Wind turbines should be sited at least
30
feet (9 m) higher than anything within 500 feet (152 m).. that is the
rule... Check this image that I have assembly with proportional data: <br>
<br>
<img src="cid:part1.02060305.04010900@olpc-peru.info" alt=""><br>
<br>
Rule of thumb: The tower needs to be 2.5 times the height of the nearby
buildings or tress ... and it will be better if there are not
surrounding
mountains (most of the
towns and villages in Peru are located in the most protected place in
the area:
the small andean valleys... even the animals that are free in the
"pampa" (flat sites) look
for refuge at the side of a hill or anything similar. I know just a
few towns that are in
"all plane" places (in "Puno" department/region/County)... but even on
those places (located over the 3,000 meters) there is not such a thing
like the "neccesary wind speed"
at flat level to move a serious "wind mill" to produce enough energy.<br>
<br>
Other "not wind" reason (for THIS project!) is that the energy power
available in the wind varies with the cube of its speed. This means
that a wind "rotor+alternator" rated at 1,000 watts at wind speed of
"28 miles per hour" might produce only 125
watts or less at half that wind speed, 14 mph. So the huge variance
add extra cost to guarantee the minimum necessary energy. Normally you
will need 8 to 13 mph winds to generate energy for a house... below 8
mph is a "hard" situation (for a house).<br>
<br>
There are formulas for calculating output based on average wind speed
and swept area: <a
href="http://www.builditsolar.com/Projects/Wind/wind.htm">http://www.builditsolar.com/Projects/Wind/wind.htm</a>
(It has a lot of other useful info for wind devices). Jim Green
(National Renewable Energy Lab (NREL)) developed other similar
calculations: annual energy output (AEO) in KWH = 0.01328
x rotor
diameter (ft.) squared x average wind speed (mph) cubed.<br>
<br>
Other "not wind" reason: Cost of the tower. 1 tower can work for many
XOs... but we need to do comparison in costs (human driven vs wind
driven).<br>
<br>
For me the "pedaling on a modified spinning wheel" is the solution.
But... time will say!<br>
<br>
regards,<br>
<br>
Javier<br>
<br>
<br>
<br>
Edward Cherlin wrote:
<blockquote
cite="mid:e574f6eb0805061755p27419029ydfc90199626045ed@mail.gmail.com"
type="cite">
<pre wrap="">On Mon, May 5, 2008 at 11:08 AM, <a class="moz-txt-link-abbreviated" href="mailto:info@olpc-peru.info">info@olpc-peru.info</a>
<a class="moz-txt-link-rfc2396E" href="mailto:info@olpc-peru.info"><info@olpc-peru.info></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Edward,
Just for your info (about energy devices).
I don't know exaclty why (I have many ideas about why! (smile))... but I
think it can be of your interest.
Javier
Hello Mel and all the people on the peripherals list,
I have been discussing the issue of energy with other fellow on the OLPC.
I am honest and I speak directly all the time: I think the solar energy is
not a realistic posibilitie in Peru: there is 100% sunny days in the Andes
JUST 6 months in a whole year. The worst moments are the 4 to 5 months were
some villages (located over the 3,500 meters altitude) get 100% cloudy time,
very cloudy, huge rainfall. According to all the investigation that I have
done (I can send to anyone if you are interested) the solar devices can
provide from 5% to 20% IF there is not a sunny day. That is a BIG problem.
</pre>
</blockquote>
<pre wrap=""><!---->
That certainly does not eliminate solar from consideration entirely.
<a class="moz-txt-link-freetext" href="http://ezinearticles.com/?Effects-of-Clouds-on-a-Solar-Panel&id=533893">http://ezinearticles.com/?Effects-of-Clouds-on-a-Solar-Panel&id=533893</a>
"Germany is typically a very cloudy country...In spite of its cloudy
climate, though, Germany is by far the world's biggest user of solar
panels."
Other possibilities are
*Wind
*Water
*Biofuels (ethanol, methane, biodiesel)
*Animal power
*Child power
How are the winds up there in the Andes?
Are villages located on or near mountain streams?
What do the farmers grow at altitude? Potatoes make a good fuel crop.
</pre>
<blockquote type="cite">
<pre wrap=""> My best understanding, based on previous experience when I have work for a
mining company is to build a mechanical device: human driven, leg driven.
But not a bycecle. We have built it before but it was without "cost"
restrictions. It is based on a spinning wheel (I have many here at my
sight). But when I have put "cost" as a variable to take in account then I
have got the next ideas:
a) Using alternators, in Peru, is expensive. Each alternator cost US$300
aprox.
b) We need to import some magnets and assembly the alternator by ourselves.
The kids on the villages can do it as part of the "experience". We must
provide the alternators, the copper wire, the circuit and components for the
rectifier, and... the battery (battery is other hard issue... short live...
expensive). Assembly this "home made" alternator, connecting to the
spinning wheel (that can need a double wheel or a "pulley" chain) can be an
improvement (according to the first results that we can get).
c) Legs are the ones that will be used. Not in a bycecle but on a spinning
wheel. It is totally possible generate enough energy for a regular laptor
with the legs, it will be easier for the XOs. Providing energy for the
XServers is a totally different issue, I don't agree with the use of
XServers. I suggest that one of the XOs MUST behave as a Server (or the
whole local XO network should behave as a "shared server" sharing processing
power... but that is a bigger task).
d) Need more energy? Put bigger magnets or "more" copper wire. Too heavy
to move? Change design: move the copper wire around the magnets. Too heavy
yet? Use concatenated pulleys.
e) Cost?: import the magnets from Korea or other asian manufacturer.
In this moment I don't have the time to develop this pilots (because I work
independently, earning bread and butter for daily living, as anyone, and my
spare time is not good enough to attack the problem in an efficient way).
So I am passing this info to you (and I can discuss and help more if there
is someone interested in develop this prototypes).
</pre>
</blockquote>
<pre wrap=""><!---->
I'll ask Engineers Without Borders and some other organizations.
</pre>
<blockquote type="cite">
<pre wrap=""> If we don't get an asnwer for the energy problem then we will be delivering
(we ARE delivering) XOs to the towns and villages that "look" poor in the
eyes of the occidental culture but we are forgetting
</pre>
</blockquote>
<pre wrap=""><!---->
No, you are forgetting that Nicholas Negroponte made it clear from the
beginning that the villages without electricity were the prime targets
for the XO, and how many people have been working to make it succeed
there.
</pre>
<blockquote type="cite">
<pre wrap="">that in Peru the deep
poverty is located in those 80,000 villages (5 million people) with less
than 100 families in each villages, without electricity, less than FIVE
HUNDRED dollars as total ANNUAL income for the family (with the work of the
father, mother and children from 6 years old).
</pre>
</blockquote>
<pre wrap=""><!---->
There are other target countries where the annual income is even less.
</pre>
</blockquote>
<br>
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