Welcome to this read-only archive of the Worknets wiki. Our content is in the Public Domain. We were active at this and previous wikis from November, 2004 to July, 2010. Please join us at the sites below where we are now active!Tweet
Andrius Kulikauskas Self Learners Network. Think Through Art with Andrius Kulikauskas. Directory of ways of figuring things out. Chicago Street Artist Blog. Video summary of knowledge of everything. Notes on Gamestorming. Living by Truth working group. Twitter: @selflearners Email: ms @ ms.lt
Edward Cherlin Earth Treasury
Kennedy Owino Nafsi Afrika Acrobats
Ben de Vries
Samwel Kongere Mendenyo
George Christian Jeyaraj
Lucas Gonzalez Santa Cruz
Christine Ax, Steve Bonzak, James Ferguson, Maria Agnese Giraudo, Marcin Jakubowski, Ed Jonas, Rick Nelson, Hannington Onyango, Linas Plankis, Proscoviour Vunyiwa
Andrius helped with the following websites:
See also: Solaroof, SolarEnergyHasPotential (Uyoga)
Come back if you want more info.
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
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
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
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).
Sales and merketing (including setting the right price).
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).
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?
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.
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
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 .
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.
http://biodesign.webeden.co.uk make 2 watt solar panels http://blog.onevillage.tv/archives/2006/01/diy_solar_syste.html Fred Migai