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See also: Solaroof, SolarEnergyHasPotential (Uyoga)
DIY Solar
Added to Internet Tue, 08 Jan 2008 13:20:38 UTC GrahamKnight: I am no expert in wireless but have met this problem in Africa due to us supplying low cost simple pv technology and advice.
We have been contacted by people in remote parts who are able to use the Internet via a mobile phone. We supply the pv panels to charge their 12v car battery.
Come back if you want more info.
GrahamKnight
BioDesign (non-profit)
Added to Tue, 08 Jan 2008 17:34:45 UTC Graham Knight: We provide both parts and advice on making and using tiny low cost pv panels so they can power radios, LEDs, mobile phones, etc.
Hello Friends,
We offer a free sample to anyone considering the introduction of this technique into poor communities.
More info is found at biodesign.webeden.co.uk
Added to Ricardo Wed, 09 Jan 2008 19:03:52 UTC Graham Knight: Hi Ricardo,
As you may have seen, I'm into low cost solar pv including the recharging of batteries. It can be done very cheaply.
Have a look at biodesign.webeden.co.uk and come back with queries
 Your mobile battery connector
Solar projects as practice for the FlashDriveEditor
Ricardo, My thought would be to develop the DIY Solar panels
( http://biodesign.webeden.co.uk/) as a dry run before moving forward
on the Flash Drive Editor because it is a similar approach and it
has been demonstrated in the field. Jeff
Good idea Jeff (using solar assembly as practice for the Flash drive
Editor).
Assembling something like a solar-power system with a
production-cost of say $3 to $5 to power radios etc would be good
experience for local workers. It's something that's immediately
useful, saleable and profitable. The actual cell can be just $1 for
a radio.
I should have summarised the Biodesign example project in the
message, instead of just giving a reference. They supply one example
system to a group in a developing country for people to copy. See
the http://biodesign.webeden.co.uk/ Home Page.
They can also source the solar-cells in bulk and arrange shipping.
On the home page, it says they can supply either cells (delicate,
but low shipping cost) or PV Plates from the UK or country of
manufacture (robust, but higher shipping cost).
If we copy and assemble systems, it would include...
Design work for the product and packaging (only a little).
Obtaining the components.
Cutting solar-cells with a glass-cutter, to the exact size needed to
power a customer's particular device.
Mounting the cell on a simple frame for mechanical support.
Soldering wiring and crocodile-clips (UK)/Alligator-clips (US).
Testing (with a dummy-load resistor and ammeter).
Packaging.
Sales and merketing (including setting the right price).
Advertising (online/offline).
Distribution.
Finance (micro-finance, easy-payments, hire-purchase, etc).
As well as custom-size cells, the team could produce standard
systems to charge particular battery-types (Nicad or sealed lead-
acid car/motorbike battery).
Please take a look at the .pdf file on cutting solar cells, on the
http://biodesign.webeden.co.uk/ 'PV Science' page, 'DIY Simple PV'
button.
In most cases, they use the cells without a current/voltage
regulator to keep costs down. They say that if the solar-cell is the
exact size to give the right maximum voltage and current for the
device (radio, mobile, re-chargable battery, etc), then it doesn't
do any harm to operate without a regulator.
This sounds plausible. Only over-voltage or over-current can damage
a device.
Their site says that you choose to cut the cells with a certain
height and width. The height of the cell determines the maximum
voltage and the width determines the maximum current. Cells can be
wired in series for higher voltages.
A radio that normally uses 2 x 1.5 Volts batteries to give 3 volts
will not be damaged if the maximum voltage from the cell is 3 volts.
It will draw whatever current it needs. If the sun is shining and
the cell can supply the required voltage and current, then the radio
will work, if not then it just doesn't work. It isn't damaged.
One opportunity for Mendenyo/Worknets/Minciu Sodas is to produce a
power-regulator unit for those cases where one is needed (for
example, for charging a more expensive mobile phone or car-battery).
This could be our own electronic circuit-design or more likely a
free public domain design from a hobbyist site on the internet. It
would provide some practice at soldering electronic components and
Printed Circuit Boards and even making/etching our own PCBs from
copper-clad board.
As you say, this would all be good experience for assembling the
Flash Drive Editor. It would also give people skills for earning
money doing electrical/electronic repair work.
I talked to Prince Obiri-Mainoo, a Mendenyo member from USA/Ghana,
the other day and he says people in Ghana repair CRT Monitors,
presumably cannibalising several units to make one good one. They
may combine one with a burnt out tube and one with a burnt out power
supply. People could do the same for computers. These are examples
of repair work leading to a saleable product and it re-cycles things.
Jeff, I see that One Village Foundation has a project in Kibera,
Nairobi ( http://www.onevillagefoundation.org/ovf/projects.html). Is
that somewhere this solar-power system assembly could be tried out?
The Biodesign site mentions Kibera and solar-power salesmen (Fomax
Direct Units company on the 'Enterprises Kenya' page of
http://biodesign.webeden.co.uk/).
Perhaps Mendenyo/Worknets users could get involved with them or set
up something similar. They mention some fairly high priced units, so
there's a niche for $1 to $5 panels for radios, etc.
Ricardo
I Think this is a good idea simply because many people in the developed world stay in no electricity area and solar can be a nice substitute more so in charging the mobile phones as we see that every body body is getting phones and electricity should not stop them
TomWayburn's calculations of the solar energy available for capture
Colleagues,
My report on solar energy in a controlled environment is ready for review by
the experts on solar energy in this group. It turns out that I had a lot to
learn (and still have) and, perhaps, I shot off my mouth prematurely. In
particular, I didn't realize that one can have two layers of solar energy
capture. Algae and bacteria are excellent harvesters of solar energy, but
they work better under low-intensity radiation. Thus, they can "see"
filtered light that has already passed through a leafy canopy above them
that shades them from direct sunlight. It is not clear what happens to the
incident solar energy that is not converted to chemical energy in the
biomass. Is it dissapated or is it available for further harvesting?
Experts in this group and other groups, to which I will send this letter in
due time, can correct what I have done and tell me what I should have done.
Please take a few moments to look at the Purpose of this Exercise and the
results for the cases where I have used (1) maximum insolation and
efficiencies whenever a range of values was given and (2) the average values
of these quantities. These appear below my signature with the body of the
report omitted. Interested persons can see the entire report, which is in a
preliminary form, at http://www.dematerialism.net/solarenergy.htm .
Tom
Tom Wayburn, Houston, Texas
http://www.dematerialism.net/
http://dematerialism.blogspot.com/
http://dematerialism.wikispaces.com/
Purpose of this Exercise
The purpose of this exercise is to place a reasonable upper bound on the
rate at which useful energy can be harvested from the sun by photosynthesis
in a controlled environment like a greenhouse. I shall not be concerned
here with the investment of embodied energy in the form of equipment,
physical plant, chemicals, etc.; but, rather, concern myself solely with the
yield per unit area regardless of the infusion of money and materials from
outside the project. This is not a study of sustainability; but, rather, a
study to determine if such a controlled environment can generate all of the
energy it consumes on the premises, which might include some liquid or
gaseous bio-fuels and some electricity. Therefore, the issue of Energy
Returned over Energy Invested (EROI) will not arise. The principal effort
will be to look for the maximum and average values of the appropriate
conversion efficiencies on the Internet.
[body of paper excised]
Result for Maximum Case
Thus, if we enjoyed the maximum values for every quantity that varies over a
large range, we would be able to supply all of the household’s direct energy
requirements. Of course, the household would be importing large amounts of
embodied energy in the form of depreciation on equipment, consumable
supplies such as soil nutrients, etc. The average American per capita
energy budget is more than 10 kW; therefore, a family of four might expect
to consume 0.5 · 40 kW = 20 kW under the severe constraint of 50% conserved.
As we have seen, the most we could expect to harvest by photosynthesis from
37.5 kW is 4.875 kW as chemical energy in biomass that would have to be
processed further. We have done very well to have harvested 1.135 kW at the
end-use stage for food, fuel, and electricity. It is assumed that energy
for cooking, space and water heating, and space cooling can be harvested
from the infra-red portion of the sunlight. Electricity can be made
available to assist space cooling if necessary since the average American
electric bill includes air-conditioning normally.
Result for Average Case
Thus, for average values of the important quantities that vary over a large
range, we would be on a very tight budget indeed, and 100 square meters
would not be adequate for all of the ancillary activities necessary for the
production of energy even, let alone living space of any kind. Moreover,
the household would be importing large amounts of embodied energy in the
form of depreciation on equipment, consumable supplies such as soil
nutrients, etc. The average American per capita energy budget is more than
10 kW; therefore, a family of four might expect to consume 0.5 · 40 kW = 20
kW under the severe restraint of 50% conserved. Or, we could accommodate
the electrical generating capacity of the average case by reducing our
entire energy budget, which is five times the world average, by a factor of
five across the board. Regardless of the intelligence applied to such a
formidable undertaking, we would be a very poor family. As we have seen,
the most we could expect to harvest by photosynthesis from 25.0 kW is 1.125
kW as chemical energy in biomass, which would have to be processed further
to meet our needs. The energy for cooking, space and water heating, and
space cooling could be harvested from the infra-red portion of the sunlight,
if it were still needed to service an auxiliary building. It would not be
possible to do anything with the greenhouse space other than growing leafy
plants for food, algae for fuel, and bacteria for electricity. A separate
space would be needed for household activities and the ancillary equipment
necessary for the operation of a greenhouse.
How costly to provide a 5 watt power supply?
How to Make a Solar Power Generator for Less Than $300
http://biodesign.webeden.co.uk make 2 watt solar panels http://blog.onevillage.tv/archives/2006/01/diy_solar_syste.html Fred Migai
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