[Peripherals] Alternitive Power for Developing Countries
info at olpc-peru.info
info at olpc-peru.info
Sat May 10 21:16:28 EDT 2008
Hello Caryl,
Wind is fine, Savonius is fine. Everything works but with its own
limitations (and advantages!)
From the same article that you tell us about:
"Much of the swept area of a Savonius rotor is near the ground, making
the overall energy extraction less effective due to lower wind speed at
lower heights."
Yes, more height then you get more wind. You need 8 mph to get enough
wind energy to supply a house energy requirements. You can find this
kind of winds at 10 meters (30 feet) over the soil surface. When we
speak that you need some "heigth" we don't mean "altitude". There are
windy places in the peruvian coast (at 3 feet altitude) and there are
windy places in the high andes (at 15,000 feet altitude and more). In
both cases you need to get more "height" from the soil surface (those 10
meters or 30 feet)... then you need a tower. Yes, I know some places
(you must know some too) that at soil level you have strong winds, but
normally we need to setup the wind mill near to a house or school... and
that school is in the middle of a city or village... then, thumb rule
applies, you need a tower that is 2.5 times (height) than the houses and
trees in the area. Furthermore, villages are build in "protected"
places (in the middle of valleys tipically... ) not in the top of the
surrounding mountains... so we need to study every case, but in general
terms, if you need serious and more steady stream of wind then we need a
tower (unlucky we are... because the tower cost money, big and important
money).
600 RPM is what the normal small car alternators require to produce
energy. So... we have two options: or we get alternators that need
lower RMP (easier) or we get a method to provide more RPM with human
movement (harder). To get (build) low RPM alternators we need to do the
next :
a) Get bigger magnets (or more magnets).
b) Install bigger (or more!) copper coils.
c) Get more speed on the "turning" of the pulley/rotor in the alternator
d) A combination of all the previous options.
"Savonius turbines are used whenever cost or reliability is much more
important than efficiency."
Sure. They are less expensive because there is no tower to build. It
can be mounted in the top of a roof. The issue is that we need to test
(aritmetically) what kind of gadget (pulleys and rotors, transformation
rate of one gear to the another one) we will connect to the Savonius
wind mill. IF we get a very low RPM alternator then it would be
possible to combine with a Savonius wind mill mounted in a normal roof
(no tower needed).
I guess that we will end talking/thinking/looking for the spare parts so
we (all) can build our own electromagnet generator (alternator).
Best regards,
Javier Rodriguez
Lima, Peru
Caryl Bigenho wrote:
> Hi Javier,
>
> Yes, I definitely agree that the folks using the technology should be
> able to choose what they want and to participate in its construction.
> If they can just be given simple plans for devices they can construct
> at a modest cost, and that will work for them, it would be wonderful.
>
> This would also take away some of the suspicion the folks have of
> outsiders who want to get them to do something new and different.
> Your tale about the water wells was interesting and a good
> illustration of this suspicion. I could tell similar tales of folks
> in Bolivia who won't accept health care, from a medical doctor from
> the Catholic church who has lived among them for decades, when a child
> becomes ill with a potentially fatal but easily cured disease. They
> say it is God's will whether the child lives or dies and they don't
> want to interfere. Many children die needlessly.
>
> There is also a political concern. If the small villages of Peru are
> anything like the ones in Bolivia (they probably are), there is a lot
> of difficulty getting cooperation among the villagers to unite behind
> a community project. Customs are ancient and really shouldn't be
> messed with by outsiders. If individuals want to do something, that
> is their business, but outsiders should not try to force things on a
> community because it would be "good for them" (unfortunately things
> like potable water, sanitation, power, communications, and the like
> fall into these categories). Maybe when groups of children involved in
> the OLPC project finish their educations and come back as doctors,
> nurses, engineers, and the like, it will change. If, and it is a big
> if, they can be convinced to come back.
>
> OK...enough of my rambling and ranting...here is what I really wanted
> to write about...
>
> What do you know about vertical axis wind turbines like the Savonius
> wind turbines? Here is a link to a wikipedia article about them:
>
> http://en.wikipedia.org/wiki/Savonius_wind_turbine
>
> There are lots of sites about them on the web...some with plans for
> ones you can build. One even uses an old 55 gal oil drum cut in
> half. Would these need a tower to work?
>
> Caryl
>
> ------------------------------------------------------------------------
> Date: Sat, 10 May 2008 01:56:31 -0400
> From: info at olpc-peru.info
> To: cbigenho at hotmail.com
> CC: josh at laptop.org; arjunsarwal at gmail.com; carla at laptop.org;
> peripherals at lists.laptop.org; hbonwit at alumni.nd.edu
> Subject: Re: [Peripherals] Alternitive Power for Developing Countries
>
> Wind? No problem: you store the produced energy in batteries that
> will feed your devices during the whole day.
>
> Some rules for wind powered projects:
>
> a) You need more than 8 miles per hour to produce energy for a home.
> b) You will need a tower. Don't trust the mills at the top of the
> house or similar designs. You need a tower 2.5 times bigger than
> the nearest building or tree. Normally you need a 10 meters tower
> (30 feet aprox).
> c) Ask the people that lives in the area.
> d) Check some of the trees... if they are growing with some
> evident tendency (right sided, left sided) then you can be sure
> that there is some useful winds in the area.
> e) Wind mills use low RPM alternators if they want to be very
> efficient.
> f) It is more efficient to set up the rotor/alternator/generator
> in a direct connection to the "turning wheel" at the top of the
> tower. Setting up a pulley system at the top and the
> rotor/alternator/generator at the bottom of the tower is not so
> efficient (there is lack of energy).
> g) Winds are not constant, they change according to the hours of
> the day and the months of the year.
> h) In some areas of Peru there is huge resistance to introduce any
> wind mill to extract water from the soil because they see like a
> weird behavior to take the "blood" from the soil when mother
> nature doesn't want to provide it in a natural way (like a
> river). In old times (around 20 years ago) there was a group of
> Dutch engineers that was killed in Puno area (the peasants
> warned... don't suck the "blood" from the soil... they smile and
> they were confident that when the population see the water running
> they will be more than happy... nope. They were killed and
> buried.). Cultural things matter. Ask local people, get the
> approval of the community BEFORE you start any study. Mining
> areas are the most difficult because the past role that have
> develop the mines in those areas during more than 500 years).
> i) There are many NGOs in Peru that have studied the issue (about
> alternative source energy). But the problem keeps the same: all
> those areas are without energy. I think is due to the size of the
> problem (80,000 villages, 5 million people). There is not budget
> that can provide enough help. If this is right (I am not sure)
> then we need to think in lowering and lowering costs for wind
> mills and let that the people of the village buy the plans and
> spare parts to assembly its own solution (if that is a wind mill
> then fine, if it is a "energy" pedaling device... is fine too!).
> If we provide spare parts, plans and it is a easy and
> understandable design then they (the people) can appropriate the
> idea and getting bigger and bigger results by themselves. One
> village past the voice to other one (mouth radio).
>
> Best regards,
>
> Javier Rodriguez
> Lima, Peru
>
>
> Caryl Bigenho wrote:
>
> Hi PowerPeople!
>
> Javier and I are really "singing the same song". His spinning
> wheel parts are very similar to my proposed sewing machine
> treadle. The principle is the same. His wonderful table
> design is just about what I had in mind for my used sewing
> machine mechanism.
>
> I don't see any problem having children use them at home.
> every child could have their own and simply pedal as he/she
> uses the laptop. It would be fun, like a learning toy, and
> that is just how they make it work. Not child labor at
> all...just part of a learning game!
>
> There is, however, value in using something else at school for
> a more centralized power source. That is where a large solar
> power, windmill, water wheel or animal driven generator would
> be practical.
>
> We need to try some of these ideas with working prototypes and
> see how practical they would be. I hope to find an old sewing
> machine when I get to Montana in a few weeks.
>
> I may also have a chance to try something with a windmill.
> What exactly is the problem with windmills at higher
> elevations? Why won't they work? If I can get a small one, I
> might have a chance to test it at about 3350 meters, 2000
> meters for sure.
>
> Caryl in Southern California...soon to be Montana for a while.
>
>
>
> ------------------------------------------------------------------------
> Date: Fri, 9 May 2008 23:47:22 -0400
> From: info at olpc-peru.info <mailto:info at olpc-peru.info>
> To: josh at laptop.org <mailto:josh at laptop.org>
> CC: arjunsarwal at gmail.com <mailto:arjunsarwal at gmail.com>;
> carla at laptop.org <mailto:carla at laptop.org>;
> peripherals at lists.laptop.org
> <mailto:peripherals at lists.laptop.org>;
> hbonwit at alumni.nd.edu <mailto:hbonwit at alumni.nd.edu>
> Subject: Re: [Peripherals] Alternitive Power for
> Developing Countries
>
> Hello Josh and all,
>
>
> >Personally, I think the power requirements for the XO is
> too high for children to charge them. Yes, I'm sure
> something can be created that children could operate - but
> is this scalable and long term? Do we think that children
> are going to want to do this everyday throughout their
> entire education?
>
>
> Getting enough energy for a standard laptop from the
> pedaling in a bicycle is possible (check YouTube.com...
> there are many working examples). Even the most
> optimistic calculation or test that has been done shows
> that is possible to do a fast pedaling for a short period
> of time, then you are done and need some rest. That is
> due that you are moving the whole leg to produce the
> rotation. And that kind of high "torque" is needed
> because you are moving and object AND you are moving a
> heavy weight (yourself). Not just moving a rotor against
> a "perfect" rolling surface (pulley and internal parts of
> the alternator).
>
>
> Then you have the other side of the coin: with spinning
> wheels (that have been used by centuries) you move JUST
> your foot (right or left) not the whole leg. People has
> been able to do this hours and hours without showing any
> sight of damage or getting tired in the effort (I know
> this from first hand because I have develop groups of
> spinners and knitters in the high andes for projects
> developed in mining zones, all of them using spinning
> wheels moved by the foot).
>
>
> Our kids, peruvians, andean kids, are used to very hard
> working conditions (most of them know very well how to
> wake up at 5:00 am and push the sheep herd to the field,
> that coould be walking around 3 to 5 miles each day...
> then coming back to the house around 5 p.m. They do this
> when there is no school or when the school just work 1
> week in the month or when they have to walk more than 2
> hours to go to the school (everyday) or when the teacher
> is out in the bigger nearest village). That happens in
> the towns and villages over the 3,500 meters altitude
> (80,000 tows and villages with a total of 5 million people
> there), not in the small villages located at 2,500 meters
> altitude (this are the ones that you can reach easily and
> have schools and teachers and kids that look at your eyes
> like very poor children but are the not the ones that are
> in the worst conditions). Any peruvian kid that lives in
> the high andes, at 2,500 or at 3,500 meters altitude, will
> look at the "pedaling" device in a spinning wheel like a
> toy, like at totally integrated part of the "cost/benefit"
> system, and only the spoiled ones will refuse to do it
> (there are "spoiled" children in any culture, time and
> economic condition).
>
>
> If that is too hard to accept (seeing as "children work"
> or any form of "slavery") then we have to think that the
> ones that will use the "spinning wheels" will be the
> teacher, fathers, bigger brothers that can understand that
> they will benefit from generating its own energy and that
> is depending on them and not in the force of the nature
> (wind, water).
>
>
> >I think what is most important is to determine the sources
> of potential energy in areas that need it, then design
> technology to utilize that.
>
> >Javier I think you have mentioned that both water, wind
> and sun are too variable to design a cost effective system
> around. Can you think of energy sources that are readily
> available in these areas that could be utilized?
>
>
> Some person have talk about energy from potatoes. Yes,
> why not. And from corn and soy and many other vegetables
> too. It is named as "eco-oil" or "bio-oils"... but...
> there is huge controversy about how much "conventional
> energy sources" are spend to produce this "bio-oils".
> Furthermore, there is huge movement against using what the
> people eats in poor countries to produce "sustainable
> oils" for use in the first world. Example: in my country,
> Peru, the government has said that the rise on the price
> of some food products is due to the rise of the corn and
> soy in U.S. and Brazil. I have talk about this too much
> with my own government but without success (politic stuff
> is not always related to the law of the economy and
> sometimes is due to personal conditions in managing some
> issues).
>
>
> Some kind of a more integral aproach could be used:
> generating energy from the gas that comes from composting
> the rest of the agricultural production and the lefts of
> the animals. But that involves much more money than
> getting, modifying, and installing some number of spinning
> wheels.
>
>
>
> >You don't happen to have an abundance of zinc ore in Peru
> do you?
>
>
> Zinc? Sure. Lots. I don't have information about
> producing energy from Zinc. But... that is a work for a
> mining company, zinc is not in the form of small rocks
> that you can pick up in the surface. You need to dig,
> melt, separate and refine. Then you are a huge mining
> company.
>
>
> Best regards and thanks for your interest in the issue.
>
>
> Javier Rodriguez
> Lima, Peru
>
>
>
>
>
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