EWB-SFP Appropriate Technology Design Team

West Africa Cashew By-Products Project Assessment Trip

2010-05-03T20:09:00.000-07:00

In late March ATDT representatives were sponsored by the ACi to visit West Africa to observe the end of the 2010 cashew harvest, and see first hand what the issues surrounding cashew byproducts are in this region. We flew into Accra, Ghana to meet the project organizers then planned to quickly head out for Burkina Faso by plane – but two days of late harmattan (sand storms) kept us grounded so in desperation we hired a car and driver and spent the next 2.5 days speeding the length of Ghana as we tried to make up for lost time. We took the opportunity to visit Ghana’s largest cashew operation, MIM Cashew, where we received an excellent introduction to cashew processing from managing director Lars Wallevik – pertaining to byproducts, they are just getting ready to introduce a cashew apple schnapps (very modern equipment), and while they burn some cashew nut shells to fuel their boiler they are unhappy with the amount of air pollution caused by the unburned CNSL. We also stopped at two agricultural research stations, in Bole and Wenchi, where we saw many varieties of cashew apples, heard about research on grafting and other agroforestry improvements, simple wine and alcohol production trials, and experiments to use dried cashew apple pomace for animal feed. Unfortunately, we didn’t have time to visit the Benedictine monastery in Techiman, where they are said to sell processed cashew apple products. Nowhere in Ghana did we get to observe fresh cashew apples (or any cashew apple product) for sale, but it could be that we were travelling too quickly; we did take every opportunity to sample the fruit and indeed found them too fragile to transport far, extremely juicy and sweet, and causing a bite of astringency at the back of the throat.

We were met at the Burkina Faso by our able escort/driver Sekou, and now that we were in French speaking territory our translator Maria Mathess proved especially invaluable. We appreciate all the help from the Ouagadougou PDA/GTZ office (the Agricultural Development Programme) – particularly Philippe Constant and Andrea Wilhelmi-Some – as we galloped from one meeting or production facility to another in Banfora and Bobo. From the second we entered BF we occasionally encountered children selling cashew apples from baskets on their heads, so we were able to use our “community engagement” tools to inquire how people value the fruit – all of the ones we tried were fibrous and the only way of consuming them seemed to be to suck out the juice and spit out the rest. As we visited several cashew production facilities (such as Sotria-B) we received the same request – help is needed particularly in extracting value from the oily shells (~25% CNSL by weight), since there is presently no way to burn them cleanly; each operation has a similar field of accumulating shells, and everyone would benefit from their efficient use. All over this portion of Africa fuel (such as wood and charcoal) is in short supply and so it is criminal that trees must be cut down when shells are so energy rich and plentiful. Later we found that a government research institution in Bobo (IRSAT, with GTZ/FAFASO) has an active program to extract the CNSL and use the remaining dry nut shells for fuel for improved cooking stoves – in cashew growing regions all over the world there is a need for simple extraction methods (and adequate markets for the CNSL), as well as ways to cleanly combust un-extracted shells for those instances where CNSL extraction is not feasible.

We also visited several cooperatives (like Association Wouol and Coopake) where cashews and dried mangoes are processed, and sampled some of the very first dried cashew apples in this region – these organizations desire new products to benefit their members so proved very receptive to learning about cashew apple products that have proven popular in other parts of the world (particularly Brazil). With Rakesh Gupta (TechnoServe) we met with representatives of DAFANI, a juice manufacturer eager to add new juice mixtures to their line, and perhaps install a biogas fermenter to capture value from their waste pulp. We spent considerable time at L’Union Yanta, both at their plant and in their cashew orchards, learning about the community that supports them. We visited a nearby home where a meeting had been organized for us to talk with families – always an important part of EWB assessment trips – and regaled several generations with our stories of cashew apple uses around the world. As always we asked “What can we do for you?”, and typically found that expanding the uses of cashew apples is probably a marketing rather than a technology problem – all the right information conceivably already exists, now how do we get it to the people who want it? Recipes, solar fruit driers, simple juicers, cooking demonstrations, technical information transfers, and so on might all be part of a comprehensive effort to encourage greater utilization of this valuable resource. And, as in most areas of the world where cooking is done with biomass, fuel is one of the largest daily expenses so access to the energy in the nearby nut shell middens would be appreciated – the best forms might be briquettes or charcoal, both areas of active interest to those developing improved stoves all over the world. For larger scale applications - say to produce process heat for industry or to provide rural electrification - gasification of shells in a reactor is the cleanest and most efficient method.

In conclusion, as we travelled we found encouraging signs everywhere – uses for cashew byproducts are of interest to everyone (and the internet is full of activities in other countries as well – waste is in no one’s best interest, so attracts attention) – and we saw or heard of examples of most of the possible uses we imagined ahead of time. The fact that commercialization of many of these has not already occurred suggests that there are hard problems to be overcome, particularly if we are to make good use of the shells. But then the expertise of ATDT members wouldn’t be needed if everything was already figured out…

Its a shame not to have more space for trip photos - you can find additional ones here!

Short video of my experiment comparing the pyrolysis (on a bed of hot charcoal, with forced air) of U.S. English walnut shells, and Burkina Faso CNSL saturated cashew nut shells. In both cases the pyrolysis gases burn nicely, and the CNSL does not seem to interfere - when they are added gradually to existing combustion. Inside a gasifier fully loaded with cashew shells we hope that the CNSL will not drain too quickly into the combustion zone as the shells preheat, resulting in noxious smoking.:

YouTube has many many videos of cashew processing throughout the world, including Thailand, Guinea-Bissau, Sri Lanka, Benin, India, Vietnam, Indonesia, Brazil, Philippines, and more. They show different levels of automation, and many discuss cashew apple utilization as well!

Intro to the Cashew By-Products Utilization Project

2010-04-13T21:07:00.000-07:00

Cashews are one of the favorites of the world’s nuts, but very few people know much about the rest of the story… the tree is closely related to the mango and a cousin of the poison ivy, it produces a fruit which is technically not really a “fruit” but an engorged stem, the “nut” (really a seed) develops outside the fruit, up to 20% of the shell weight is a valuable industrial chemical, it is raised in countries all around the globe, and the Bill and Melinda Gates Foundation has recently taken a special interest in improving cashew production methods in Africa. Through the African Cashew Initiative, their generous funding seeks to extract more value for Africa from the cashew crop – presently raw nuts are shipped abroad for roasting and packaging, when these operations could be performed locally, benefitting the communities where the nuts are grown. A specific goal is to find more uses for by-products – like the fruit and nut shell – so that small farmers can obtain additional income, improving their quality of life; EWB-SFP has committed to helping find or expand uses of these valuable resources.

Cashew trees originated in Brazil and were spread by early Portuguese traders (often simply to prevent soil erosion), but they often forgot to spread the word that the “cashew apple” is as delicious and nutritious as the nut – the juice is extremely popular in South America, and in Central America often the nut is discarded as not particularly useful but the apple has an important place in markets. All kinds of prepared foods – jam, chutney, drinks, dried fruit, candy, etc. – are consumed in other cashew producing countries (such as India and Vietnam), but what happened in Africa? Sometimes information just doesn’t flow evenly, and we hope that with some encouragement the situation will change. Of course if it was as easy as that no outside technical assistance would be needed, but in sooth the cashew apple is very soft when ripe so does not transport or store well, and it contains tannins that must be removed because they give it an astringent flavor.

Making full use of the nut shells has its tricky parts too – while the oil in them (CNSL) is valuable for use in polymers, coatings, and auto brake components it is also noxious (it causes a skin rash much like that from poison ivy) and difficult to extract. Again, sometimes we need to move technologies around the world, adapting them to new circumstances – our challenge is to do it in a way which is most appropriate for Africa. With or without the oil, the shells have a high energy content, making them suitable for providing process heat for industry or fuel for improved household cooking stoves… except that the simple technologies needed to turn them into charcoal or briquettes don’t exist there yet, and when burned in a typical way the oil produces an unacceptable amount of very unpleasant/acrid smoke. For now the landscape is littered with huge piles of messy shells, while scarce wood resources are consumed in their place.

What can ATDT do to improve the situation? As always, we’ll first seek to become minor experts in apple and shell uses around the world (we always do our homework), learning how these problems perhaps have been overcome in other places, and we’ll visit West Africa to see what the people and communities there value. Without meeting our local partners (GTZ manages the program, but there is a whole suite of professionals from TechnoServe, the African Cashew Alliance, Costco, and similar involved) and our end customers (the small farmers and cashew processors who would benefit from new ways to utilize these “waste” products) we can’t determine what paths might be best. We also have members who have recently visited Brazil and Vietnam, to examine their situations and see what we might learn from them.

Next: results of the site visit to West Africa!

The Case for Tiny Wind

2009-11-11T15:47:00.000-08:00

We have been working with the Appropriate Infrastructure Development Group (AIDG) on small wind generators for their clients in Guatemala, and recently were fortunate enough to be able to use a wind tunnel at NASA Ames in Mountain View, California - to characterize two turbines that we have been developing. Tyler describes the experiments here, and now we continue with some more general discussions.

Working squeezed/scrunched up in the belly of the Army Aeroflightdynamics Directorate 7’x10’ wind tunnel gives one lots of time to think about the world and our place within it, and how these “tiny” wind generators (the term “micro” has already been claimed for systems up to 5000 watts) can help contribute to an improved quality of life for some. Remember the target market is people who either have zero access to electricity, or who perhaps depend on charging worn out car batteries in distant grid connected towns – you pay bus drivers to transport your battery back and forth – to get a trickle of power. How people use that first few watt-hours of high quality energy they have access to fascinates me, since while we sometimes have an impression that everyone else wastes scarce resources too, in reality people with scarcity tend to know the value of conservation and wise use best – especially when their costs are high.

Extending their day by a few hours with an efficient light is usually the first use – most unconnected places seem to be close to the equator where the days are always short, and recurring costs for candle/kerosene lighting are cumbersome/prohibitive – allowing people to read, do homework, and maybe even earn extra income. Charging batteries – for flashlights, the radios all campesinos carry to the fields, and cell phones – is another priority, hopefully reducing the number of discarded disposable ones that litter the ground. Both of these applications require very little energy – for us it would be worth just pennies worth a day, but for people who all year around are used to calling 6 pm bedtime… priceless! And yes, one of the first appliances to appear is the ubiquitous television, often for soap operas and soccer matches, but also news and education.

Just a hundred watt-hours a day will do all kinds of things when the appliances

s are efficient, and in a breezy location it shouldn’t take an expensive turbine to provide this. As a slightly technical aside, it is best to remember that people use energy to do things while we have a tendency to express the output of wind generators (and photovoltaic panels, and microhydro installations, and nuclear power plants) in units of power (watts). The wind tunnel tells us how many watts we might generate at a given wind speed, but winds fluctuate so we can’t count on getting that much all of the time. Commercial turbines are almost invariably rated just in watts, and you always have to ask “At what wind speed?” – and you’ll quickly find that they choose to rate at some phenomenal (and usually unrealistic) value, like 25 miles/hour (~11 meters/sec). Southwest Windpower (http://www.windenergy.com/products/whisper_100.htm) has now started doing the right thing by helping you estimate how much energy (in watt-hours… each one of these helping to perform a useful task, such as a one watt LED lamp aiding a kid do homework for one hour) you might expect to generate from their products, after making some assumptions about your local wind speed distribution.

This brings us to the question “How do we extract power (and energy) from the wind – which comes originally from the sun?” The maximum power available from the wind, per square meter of turbine swept area, can be easily calculated from the equation

Power = ½ rAV³

where r is the density of air, A is the swept area of the turbine, and we see that the power increases as the cube of the windspeed (doubling the windspeed gives 8 times as much power), so that while there is lots of power produced at high wind speeds there is almost none available at very low speeds. Our Lenz blades sweep out an area of .75 m² (the Savonius configuration we tested is .45 m²) and we know that we can only realistically have a fraction of the energy the wind contains – Albert Benz said that 59% is the maximum, but more like 30-40% is typical for small tubines like ours. So the amount of power you can tap into depends on how much the wind blows, and with like so many other things (like per capita income) the averages provided to us by the government don’t always do us enough good – some days it doesn’t blow, some days it blows too much, and luckily some days it blows just enough for your turbine to fill up your batteries for the coming week. That’s the concept of the distribution (vs. and average), and luckily the wind speed variability tends to follow a Weibull distribution (http://en.wikipedia.org/wiki/Weibull_distribution), a statistical function, where just two variables describe the distribution. These are the average wind speed and a number related to the general amount of time with no or low winds (the shape parameter), and this site http://www.reuk.co.uk/Calculate-kWh-Generated-by-Wind-Turbine.htm does a much better job of explaining it than I can here – and they allow you to type in your power vs. wind speed data (such as from wind tunnel testing), plug in a shape factor, and get the anticipated energy output (say in watt-hours/day) at your target location. Now you can buy the right number of storage batteries to get you through the wind-less doldrums, and compare the cost of your tiny wind system with your other electricity alternatives – including continuing to charge your car battery for the equivalent of $3/kW-hr, and waiting a long time for the grid to arrive.

Taking the raw wind tunnel data Tyler showed (torque and power vs. RPM) we can determine the maximum amount of power a given blade set or configuration can extract from the wind at each speed and plot it – that upward curved shape is very important because it tells us that not much power is available to us at low wind speeds (say, less than 10 mph) Our experimental method did not include a generator to turn the winds power into the electrical power we need to run appliances, and there will be losses in this conversion process – we expect it to be ~75% efficient - so we have to take this into account, giving us the ability to get about 25% of the energy embodied in the wind – not bad if the resource is free.

As mentioned, a single “power rating” for a turbine is not very useful (and only meaningful if the wind speed it was measured at is associated with it), but people are used to hearing just one number so we may need one. Catapult Design will tend to rate these turbines (a set of blades plus the associated generator) at more realistic wind speed values, like 15 mph (7 m/sec), and then we’ll do our best to try and characterize the wind resource at a specific locale. If we choose to rate at 15 mph, for example, then the real power output of the Lenz blades is ~30 watts, and the wind will need to blow at that particular speed for ~3.5 hours/day to provide 100 watt-hours of energy per day to a family or small business. Blowing at half that speed for twice as many hours does not do us much good, since the blades of VAWTs often don’t start turning until 8 mph, and at 10 mph we might have to rate these tiny turbines at only a watt or 3. For estimation purposes, Weibull wind speed distributions with very low shape parameter values would be an example where it blows very little, much of the time.

Its unfortunate that life is never as simple as it needs to be – it seems like that if a family wanted to consider buying a tiny turbine at X dollars, to decide whether it is worth it they need that power performance curve for it, decent information on their local wind conditions, and some idea how much electricity is worth to them (for example based on how much they are presently using and the cost for charging that car battery, or how much more they want to use – say if their neighbors pay them for charging cell phones). Now if we just knew the probable lifetime and annual maintenance costs we could start to understand the cost of each future watt-hour… what an exercise, and don’t forget that investing in all forms of renewable energy is tantamount to buying at one time all the electricity you will use for the rest of your life, which is not an easy decision to make.

An interesting resource for evaluating the performance (energy generated per unit time) and financial characterisitics of a wind investment can be found here: http://estimator.solar-estimate.org/index.php?page=wind-calculator and while you have to play some tricks on it to simulate this size of wind generator (technically it would be rated at ~200 W at a traditional wind speed like 25 mph) in an off grid location where electricity is presently very expensive to acquire. It is a good tool for showing what steps are required for determining fiscal suitability, and along the way it will teach you a little about wind energy - for example, at my home in Berkeley it says that I should expect an average wind speed of 10 mph and a Weibull distribution shape parameter of 2 (I may disagree, unless they mean at the sailing marina). It is not detailed enough to take into account our specific turbine characteristics, like efficiency and cut in speed, but nevertheless is is interesting to consider their estimate of 75 kW-hrs per year of energy generation for this turbine and location. My utility bill says that last month I used 127 kW-hrs of electrical energy (needing 175 watts of power capacity), for the privilege of which I paid a grand total of $16, or ~$.13/kW-hr. Clearly a turbine providing only 75 kW-hr/year would give me $10 of energy annually and just meet a minuscule part of my demand - hog that I am, with all my phantom loads from consumer electronics - but if my cost of electricity was instead several dollars per kW-hr instead of a fraction of one then the situation changes, and tiny wind may make sense for my family or business.

EWB-SFP and the UCB/Google Pre-Engineering Camp

2008-08-01T15:31:00.000-07:00

Part of EWB's mission is to educate and encourage the next generation of engineers in a way that leads them to want to be involved in technical humanitarian activities - it can take up to a generation to change society (to recycle more, use efficient light bulbs, reduce individual carbon footprints, have broader horizons than just your own country, etc.) so the best time to start is now. Google has graciously funded, University of California (Berkeley) is hosting, and EWB-SFP is teaching engineering topics to 30 gifted high school students this summer - we have projects on developing world fuel efficient stoves, pico wind energy (Guatemala), solar water pumping, and designing a water distribution system (Tanzania). Work sessions take place at UCB but we also have off site workshops for more detailed experiences.

As an example, Charlie Sellers' two 5 student stove teams are investigating options for cooking stoves in places where there is not nearly enough fuel for everyone - the refugee camps in Darfur are a good example of this so it is appropriate that one of the stoves being tested is our own Berkeley Darfur design! Their goal is to document experiments where they compare a typical 3 stone fire with various improved stoves burning a wide variety of fuels - such as ordinary wood, charcoal, paper pulp and sawdust briquettes, walnut shells, and more. There is no better way to test a new stove than by tending a fire in it for awhile - a real mother and cook has to tend sick children while cooking, and if the baby is sick then she has even less time to spend on a clumsy stove.

Wood is so scarce around these denuded camps that even saving half the wood compared to simple stoves may not be sufficient (but it sure helps) - the world is just starting to consider whether we need to re-think our approach to helping in large emergencies/disasters like this by providing instead densified waste biomass (a fancy term for briquettes of non-woody materials), either for the latest generation of improved stoves (like the sheet metal one for Darfur) or for briquette specific stoves like fan assisted gasifiers. Whenever there is a tsunami or major earthquake, enormous amounts of supplies are rushed in by select NGOs because other kinds of aid can't respond fast enough to replace an entire destroyed infrastructure - it is not the intention to replace everything for the long term, but immediately provide basic human needs like clean water, sanitation, shelter, and cooked food. We're not talking big screen LCD televisions here, just enough to stave off hunger and disease until the needs of millions of people can addressed more completely. As such, emergency stoves and fuel can be airlifted in, alleviating suffering and reducing the immediate impact on the local environment - these inexpensive stoves might only last until the emergency is over, but they may change the way they view stoves and cooking for the rest of their lives.

The students are creating presentations for Google HQ where they analyze how people cook, what they need out of their stoves, and which fuels might be best suited for a range of situations. One of the biggest challenges in the field is to overcome the natural resistance to change - if their mother did not cook with a new stove design or fuel, then the present generation of cooks might not want to either. Technology "fixes" which are not introduced appropriately are usually doomed to fail quickly - as soon as the engineers disappear the benefits don't seem nearly as apparent, spare parts and maintenance efforts are nowhere to be found, and people just plain have a tendency to prefer or to revert to old ways.

For a view of what things looked like, here is a preliminary Youtube video (Pat Coyle is behind the camera) of the day Alex Brendel visited to explain his briquettes made from waste such as paper, sawdust, and even algae. And here are some photos!

A visit to The Shipyard on Saturday gave an opportunity to try another type of improved traditional stove (the Justa, for Central and South America) and see a range of larger biomass gasifiers - including one that will run a car just on walnut shells. We cooked on the Justa, which seemed to take only a few sticks at a time to cook for everyone, with zero smoke coming out of the chimney. Everyone's experiences were accompanied by data taking, so that results could be graphed in Excel spreadsheets - the temperature of the water as it came to a boil, the amount of fuel used per minute to cook, and the temperature of the chimney gases.

2007-12-08T01:04:00.000-08:00

Experiences Using a Hand Crank Generator for Fan Stoves

Charlie Sellers and Brad Ballard

January 2008

For about four months I have had a hand crank powered LED flashlight that I have been very impressed with (http://www.freeplayenergy.com/products/illumination/jonta, and other retailers such as REI sell it for less - ~$50) – it can either be charged by its AC adapter or by turning a hand crank, the high performance LED is extremely bright, the flashlight has several intensity settings, it lasts longer on a full charge than I can easily measure, and my model is heavily rubberized for ruggedness and waterproof characteristics. It is by far the best of the many LED flashlights that I have tried, including both moving magnet and straight battery powered ones – this one seems very bombproof and efficient; several of us have been very pleased with it.

Brad’s flashlight broke after it was submerged in water so we had the opportunity to disassemble it and both investigate its construction and measure its electrical characteristics, and then use it to power the commercial WoodGas campstove. A very successful experiment showed that we had plenty of power for the fan - this is all contrary to my previous comments, because it uses a well designed generator that is well matched to this particularly efficient stove fan – it supplies the correct voltage and it has enough battery life,

Upon opening the broken unit we were very impressed with most of its construction – the 2 beautiful circuit boards were ruined by the exposure to water, the LED turned out to be the very high intensity 1 watt Luxeon Star warm white model (http://www.luxeon.com/pdfs/DS23.pdf, with a forward voltage rating of 3.42 V, 350 mA – USD $9 each when purchased separately), the batteries were very low capacity (three 1300 milliamp-hr NiMH batteries with a total parallel rating of 3.6 VDC, while good rechargeable AA batteries have 2500-2700 mA-hr of capacity each, at the same 1.2 VDC) but adequate, the generator was a nice sintered NdFeB magnet version somewhat like those used to drive HDD and CD/DVD drives in computers, and all the electronics were surface mounted (the most modern method); there was nothing to complain about except for the 2 nylon gears, that might wear out too quickly with hard use.

We removed the obviously ruined main circuit board (which

contained somewhat unnecessary

control/indicator functions like switches and status

LEDs) and then rewired it so that we had access to the unadulterated output from

the generator’s alternator – this is a 3 phase motor connected to a resistor

bridge circuit board, which then produces a simple DC output. We could then use the manual crank to produce an incredibly bright light output, or connect it directly to other loads. At the leads we measured a voltage of ~4 VDC and ~250 mA at ~1 turn per second – approximately supplying the 1 watt that the LED is rated at (and we could power the LED without the removed circuitry – from the bridge we got a smooth 4 VDC for the LED or for other purposes). We don’t know yet how many mA-hrs of energy each turn of the crank generates.

The commercial TLUD WoodGas’s stove fan also requires only about 1 watt at 2.5 – 5 VDC (quite efficient - it is designed for 2 AA alkali batteries, but I usually use 3 NiMH AA batteries to achieve a similar voltage, or alternatively I sometimes use for testing a variable voltage power supply for up to 5 VDC – above that the motor sounds unstable). We used the simple hand crank mechanism (with just the 3 phase power converted to single phase) to power the WoodGas fan, both with and without the LED in series (together, for amusement only and to limit the voltage). Lo and behold, this hand crank generator powered the fan beautifully! Fortunately the voltage was approximate matched to that needed by the WoodGas fan. At ~1 crank/sec we got good flame (no smoke) from the stove and easily cooked quesadillas quickly. When we got down to the “charcoal stage” (after the obvious yellow flame disappeared) we inserted a device to occlude all of the secondary air holes at the top (a trimmed stainless steel hose clamp, spring fit – doubling the primary air flow at the bottom of the stove) and again easily cooked another batch of quesadillas. We thought that the mostly constant cranking was a little tedious, and that a treadle powered mechanism (like an old sewing machine) would work better; this company also sells a foot generator for 12 VDC power output to any device.

http://www.freeplayenergy.com/products/portable-power/weza

Now that we had prowled the interior of one, we could hack my own functioning one to power a commercial WoodGas stove – I just took the necessary screws out, attached wires to the LED, used 6 ft. of wire to allow for powering the stove from a distance, burned a hole in the flashlight casing to pass the wires out, and soldered a new power plug on the end. Now I can use the 3 intensity settings with the fan (the setting for pulsing/blinking the power might just work to save energy using a fan stove…), and the batteries charge if there is extra cranking. Trying it on a stove with wood pellets it performed beautifully, with the voltage/power evened out by the battery circuit – always constant and just enough. One minute of cranking from completely discharged batteries seems to yield from 1 to 14 minutes of fan time, depending on the setting. With a full charge (from the AC adapter, or an unknown amount of time spent cranking) we can expect to get many hours of operation, and by installing a simple switch we can turn off the LED while the stove is on

Initial experiments put the stove fan in series with the LED, then in parallel, but finally the best circuit is to isolate the fan from the LED with a simple switch (single pole, double throw) so that the two can be operated independently – a full charge then powers the fan at very high rpms for +2 hours, and with this particular flashlight we have more fan speeds than the WoodGas stove has usually. This stove is designed for 2 AA alkaline batteries and has 2 settings, but the 3 AA rechargeable NiMH batteries that I normally use with a speed controlling rheostat are better (a PWM controller is even better - both environmentally, and it permits both a higher fan speed and a longer run time – though the motor is not designed for these rpms) – and this flashlight approach permits even more variations (including the pulsed mode).

It is still unknown how many turns of the crank it takes to power this stove for a meal – if you charged it fully (AC or by hand), the 3 AA batteries are somewhat anemic (you can easily buy ones with twice the energy capacity of these) so few hours of operation result – you can calculate this, and maybe my flashlight version is just outdated. And remember that you cannot extract all of the energy from any battery: http://en.wikipedia.org/wiki/Nickel_metal_hydride_battery.

Charging with the AC adapter was a tad curious – it seemed to take too many hours before it indicated that there was a full charge. Further experience showed that a one hour charge (from a dead discharge state) resulted in 30 minutes of full fan power (or at "low" LED power of closer to 14 hours - the obvious reason for more like 14 hours, a clear reason to use a higher efficiency motor or better fan blade design, such as the Philips stove uses) – any project would want to analyze the situation further, since every load is different.

An ultimate WoodGas batch of fuel might be 400 g of wood pellets (as are used in North American pellet stoves), which requires ~20 minutes to burn completely at the full fan speed (stove firepower is generally correlated with fan speed) – several hours of energy then corresponds to a number of batches of fuel with this stove, a very considerable amount. More typically, batches of ordinary fuels (wood chips, pine cones, nut shells, etc.) are closer to 100-150 g so this same amount of battery energy would not result in nearly as much total energy output – the denser the fuel (in g/cm³) the better this type of stove performs for the user.

In conclusion, an efficient and rugged hand cranked generator can easily power a efficient fan motor for biomass cooking stoves – provided that they are electronically voltage matched (a simple circuit can do this) and that the generator is of this quality. Other applications (such as for off grid operation of medical instruments) can similarly be supplied with power, but a decent knowledge of the requirements – e.g. volts, amps, watts, LED lumens, and mA-hrs of energy storage – is recommended.

LEDs and Other Technologies for Producing Light

2007-10-26T18:23:00.000-07:00

Whenever I come across a technology that is not well summarized on the web I feel an urge to take all the information accessible and blog on it - so everyone else does not have to fight as hard to find all the links, and get all the necessary information... like I did. Lighting, by whatever method, is one of the handful of areas that we involved with appropriate technology need to be familiar with - in addition to quality shelter, decent sanitation, clean water, efficient cooking, secure production of food from their agricultural efforts, and good health. This week I became particularly interested in lighting again (I pushed compact fluorescent bulbs since the early '80s, when they were expensive and regularly problematic - now they are cheap and mainstream) after I recently did a workshop on photovoltaics (see the post below) for emerging economies - high grade electrical energy is hard enough to produce that you want to consider what might be the best lighting for your electrical system. In remote locations electricity (from sources like solar, hydro, wind, etc.) is so expensive that the lifetime cost of electrical devices is far more important than their purchase price - operating costs (for lighting, something resembling the cost per lumen) are the largest proportion.

The trouble I found was that it is presently too complicated to compare different kinds of lighting products - especially if we want to focus on the quality of light instead of just the quantity (or the cost, or combinations of various parameters). The most common types of light bulbs available to consumers are the incandescent, the fluorescent, and (just recently) the LED (light emitting diode - I believe in anticipating the future, since technology never seems to stand still) - there are many other types like metal halide, sodium vapor, kerosene lamps and other combustion based, neon, high intensity discharge, sulfur, etc. but these are mainly used for industrial applications or are not electric). I thought that lighting selection for energy efficient applications (like ones powered by alternative energy) was as simple as "light output per watt of electricity" but have just found out that life is not that easy - other things come into play if you really want "good light". First, let's define some basic lighting terms:

lumen - a measure of the amount of light produced, but it does not describe how well that light suits the eyes of human beings.
luminous efficiency - what portion of the emitted electromagnetic radiation is usable for human vision.
candle power
CRI - the color rendering index compares a light source to daylight in the way that it makes a colored object appear; higher CRI values mean that things look closer to how they do at noon, in natural sunlight (CRI = 100). Lower CRI values are acceptable when colors are not important, like for street lighting, while very high values are desired when you want a retail item in a store to look its very most colorful.
lifetime - an ill defined term to describe how long a product is expected to last in service, but usually it is only for ideal conditions (moderate temperatures, not too much switching, etc.), and this number does little to describe how many parts will vary (the statistics of reliability and lifetime - mean time between failure, distribution of failures over time, etc.)
color temperature - a rough comparison of how the frequency distribution of the light compares to that of a "black body".
environmental sensitivity - how stable a product is as the temperature of use changes; some technologies for example don't perform as well when the temperature is cold.

Every time we need light we tend to need a certain combination of these things - just cheap lumens are no good if we want light of reading quality, and efficiency doesn't make much sense if the lifetime of the bulb is too short...and in reality there always seems to be trade offs. Life would be relatively easy if we could just choose one parameter as "most important" when we are selecting a bulb, but I have found that there is unfortunately more too it than that - if you are looking for an easy solution then stop here.

Most of us are familiar with the venerable incandescent bulb - a hot tungsten filament that gives off mostly heat, but some light as well (I think of them as "resistive" bulbs because when current flows through a wire with a high resistance it gets hot, and it also happens to glow somewhat in the visible spectrum) - and also fluorescent bulbs - either in linear tube or "compact" varieties - where the bulb is cooler and more efficient (less heat, more light). Compact fluorescent lights (CFLs) have recently become very popular with the gov't and media, but when they were first offered they did not seem to be a very realistic alternative to incandescents - now their combination of characteristics is such that several countries have banned resistive bulbs with the expectation that consumers will buy CFLs instead and thus reduce the need for additional electrical power plants. Prohibition will have the usual problems - fewer choices will mean some disgruntled users, since incandescents have their benefits for some applications. Light emitting diodes (LEDs) are a newer form of "solid state" light - sort of the opposite of silicon-based solar cells, where when light falls on special semiconductor devices we get electricity. In an LED an electrical current causes energy transitions in these more exotic semiconductors, and then light is emitted - with much less heat produced as an unwanted/unnecessary byproduct. But LEDs are a newer technology, so they are still under development - much like CFLs were in the 1980's when they were more expensive than we would have liked - but luckily technology advances in response to our needs, and this will happen with LEDs as well. If we can just be patient, and encourage the technology by investing in new products, we'll soon have better solutions... and then the next improved lighting technology will start to evolve (such as microwave sulfur lamps, or electroluminescent wire - if its not just a Burning Man thing). Such is the nature of science.

So this week I invested in my very first LED bulbs, trying various different styles (5 different ones) - all "Edison" socket ones, like fit household fixtures. It was fascinating how different the bulb appearances were - unlike incandescent bulbs the exterior of each one of these was completely different! This alone would confuse many consumers so I predict that these differences will eventually go away - consumers want to compare apples with apples, so only minor differences in appearance may be acceptable if the other properties are the same. And the color of each was different - their specifications should have indicated that they would be (and they might be - to a more knowledgeable consumer), but I just assumed that they would combine different types/colors of LEDs so that all would be (more or less) equivalent and optimal for the human eye. Nope, each one looks different to me, but because I am technically colorblind I don't assume that my color judgment is worth a damn.

I was surprised to find that they are many things, but not necessarily more efficient than CFLs for alternative energy (or other) applications - my lights, ranging from 1.3 to 3 watts for a total of 12.5 W, cost $84 and have a rated total output of just 285 lumens (both the wattages and the lumens seem to be approximate though), leading to a very pricey 23 lumens/watt. Individual bulbs were as efficient as 40 lumens/watt but they are not marketed according to to this measure. For comparison, common CFLs now cost $2-$4 for an 11 W bulb, which puts out approximately 600 lumens - an efficiency of 55 lumens/watt; one of those bulbs then puts out twice as much light as all my new LED bulbs, at twice the average efficiency, for a tiny fraction of the bulb cost! But I am simplifying too much here - other 11 W CFL bulb models may not be as efficient or long lasting, very few of them can be used with a dimmer, they tend to decrease in intensity a little over time, etc. And we have only compare cost and efficiency, not all the other factors which may also impact your decision. The table here does a much better job of assessing just the luminous efficiency comparison for various lighting technologies, showing that incandescents are ~2.6% efficient (it depends on the wattage - efficiency of these and fluoescents tends to increase with wattage), CFLs are ~8% (the latest T5 straight tubes are more like 15%!), and present LEDs are up to 10% efficient but results in laboratories show the potential for more like 22%!

Now we can start to see that LEDs will tend to be better for small output bulbs (such as those that are typically used in alternative energy systems where the cost of each extra installed watt of capacity approaches $20, and they are generally suitable for developing countries where there is not such a tendency to "over illuminate" homes), and where they will be valued because they are unbreakable, dimmable, longer lasting, and available in so many colors and configurations. And, while CFLs are a mature technology that is well on its way to predominance, LEDs are still improving so their future efficiency and costs are yet to be seen. Now I feel better about my new investment in them - I am cutting edge. In the developed world we are seeing LEDs used just for their color variety - in traffic lights, billboards and other forms of advertising, nightclubs, art installations, etc. - and it may be some time before plain white ones are used for lighting alone, since incremental efficiency improvements are not as highly valued.

The bottom line? Be prepared to ask a lot of questions if you want the very best light technology for your application. Incandescent bulbs have a long history so people are familiar with them and they are perfect for some applications, fluorescents of various types are the near future and will continue to get better with time, and LEDs will be coming down in price at the same time as they are improving their light quality and efficiency. And there will always be something that is next.

Green Empowerment Workshop - PV/RE in Developing Countries

2007-09-30T21:01:00.000-07:00

Heather recently sent around an email saying that there would be an Oakland photovoltaic/renewable energy workshop that would focus on sociocultural issues of developments as well - exactly the direction that I'm headed toward now that I have decided that the "technology" part contributes only maybe 10% to the probable success of the project. Human dynamics, cultural differences, education, planning, maintenance, risk management, etc. seem to make up the rest of any possible local solution. Green Empowerment seems to focus on bottom up development (vs. big plans and big money), allocating most of their funds for local NGOs. They lead tours, advise, install, and teach good things like principles of solar cells for electricity (e.g. lights) or water pumping, and pico/microhydroelectric.

The 2.5 day workshop included both technical aspects - everything that you could imagine about planning a PV system - plus a discussion of things that went awry in countries all over the world (cultural issues). Unlike many humanitarian aid projects, solar power installations require a moderate amount of technical skill in the community - some solid state physics, decent electrical practices, and a good sense of maintenance/troubleshooting if the project is to succeed for years. The global PV industry (now in almost every country) still sells mostly "components" and then users have to specify what they need to provide enough power, order the right pieces (there is lots about all this in the GE handouts for the class), wire it all together, test if for mistakes, and train the populace - not particularly a consumer friendly process. And there are all kinds of assumptions that need to be made in sizing a system (too big is to be avoided because of $), but in the end you round up number in the number of solar panels and batteries so it doesn't really matter that you have uncertainties. Except that the cost can be higher.

Demos and hands - on sessions gave people experience with all the components, and with wiring them all together, and I'll be building my own tiny system soon. There might be +10 years until household solar is mainstream (I remember trying to promote compact fluorescents, CFLs, 25 years ago, when their quality was poor), but I saw the need for a handful of engineered widgets that might help hurry solar measurements along. LED lighting is going to be the next big thing (look at the lumens per watt table in the middle), and research is making them better everyday. Exciting to be on a steep curve for a new material - commercialized but still under intense development. The auto and industrial markets are going to be first adopters, because they measure costs much more carefully - watch their $/lumen costs. And here are 120VAC LED Edison bulbs ($1-$2/lumen). But using auto LED lights in other applications is hampered because they require special sockets - has anyone seen socket adapters to convert 12VDC "twistlock" or "bayonet" car lamps into household screw "Edison" bulb bases? A little adapter can be co-injection molded (to insert the metal parts) that should only cost $1 - but is it really needed by the people in the field? I think options will be needed because auto lamps are available in a variety of low wattages, they are dropping faster in price than residential bulbs, there are many incentives for improvement, there will soon be an incredible number on the market (economies of scale), etc. Let the auto industry do the work and home PV systems will benefit for free.

Also, a few more diagnostic tools may be needed - some manufacturers build more features into their best products, but for example is there a tiny, cheap power meter that can be used for various purposes? A kW-hr meter is not needed to charge homes for the exact amount of electricity they use, but it would be handy to see how the PV load is distributed throughout the community, and over time. Or battery characteristics - state of charge, health, input and output, etc. Someday the best of these parameters will be clearly shown on a standard panel (like consumer electronics now) that makes solar easy, but for now a little cheap datalogging and some USB connectivity wouldn't hurt.

And, the more I look the more I find - industrial lights (floodlights, streetlights, traffic lights) are here http://www.ledtronics.com/ and I am still trying to figure out why a traffic light seems to cost so much less (in $/lumen/watt, or similar units) than %$#@&! consumer models.

One thing that will take time to seep into the mentality for PV installations everywhere is the drive for quality that system manufacturers in other industries (automobiles, computers, DVD players, medical instruments, and similar complex things) now use to increase reliability and prevent consumer problems. From the start of a project new ways to determine risk (system too large or small, things that might happen to break the system, quality of components...) should be identified and then slowly reduced. This kind of thing is what can be missing when things are manufactured in developing countries, where quality is a new concept (the last thing to learn in every new business). But QC tools are everywhere - new types of connectors (so no mis-wiring), error proofed maintenance, more robustness, better instructions, community participation, an overall rise in familiarity with technology, etc. will eventually make solar as easy as connecting up to the big grid (plugging into a wall socket) right now - and for now we can just try to facilitate this change.

next post - I'll try to review the recent book "White Man's Burden", which postulates that grassroots efforts like these are the best solutions - and big aid projects are doomed because they provide none of the right incentives.

Developing World Water Quality Issues and Technologies

2007-02-08T15:45:00.000-08:00

Clean water problems in developing countries are pervasive (along with shelter, sanitation, food, and other core quality of life issues) - almost every EWB team deployed overseas can expect to be asked to help improve the water quality, and just finding clean water for themselves to drink while they are there is a concern as well. There is no single solution - every area has its own needs, on a variety of scales from just for one person, enough for a field team or family, sufficient for an emergency situation of any size, or for the permanent needs of a remote village. There are all kinds of different water quality problems, dozens of types of ways to use technology to address them, and a wide range of costs - all have to be taken into consideration. A fantastic first resource is the great general overview from the World Health Organization(WHO) on bad water in general
Managing Water in the Home: Accelerated Health Gains from Improved Water Supply - 83 page .pdf document (or 11 chapters/web pages).

Another good resource is the summary of the 2004 conference "International Network to Promote Household Water Treatment and Safe Storage" with the complete document available from the Center for Disease Control(CDC) with very good references.

The CDC also has a one pager Preventing Diarrheal Disease in Developing Countries:
Proven Household Water Treatment Options - with links to get details on a few favored technologies (for example, see the PuR product - flocculation plus disinfection):

Just as its name implies, Safe Water International covers all types of purification, and the link on Commercial Filters has 15 pages of details on
different commercial models. My latest experience with a filter in the field came in Guatemala last month, at the tiniest cafe in a tiny village - they had a beautifully simple double bucket system from HELPS. HELPS is a U.S. charity known primarily for its plancha stoves in Guatemala, and now I see that they are also involved in coffee, corn, and clean water projects and products. The water filter ceramic they use is a commercial one made by Fairey Ceramics, a U.K. company that makes parts for other water filters as well. As a materials scientist I am interested in modern solutions of this type - and there are many other first world suppliers of technical porous products that are used in developing counties, but I see that these can also be made by blending clay and fine organic products (like sawdust) which are then fired (to burn out the organics and form pores)in a simple kiln. Potters for Peace (but this site has
better info on it) promotes this technology and trains local people. International Development Enterprises is an interesting group (are there no end to these other AT groups similar in purpose to EWB?)who believe that the rural poor are customers, producers, and entrepreneurs, not charity recipients - so they use market forces to provide technologies such as simple water pumps (hand, treadle, and more coming soon), drip irrigation, water storage, rainwater harvesting, and similar. The promote selling the Potters for Peace product, mention an arsenic filter technology.

And here are more engineers offering help with silver impregnated locally made clay filters! Engineering for Developing Communities, offers help with other technologies as well.

Another sustainable technology is slow sand filters and they are among the simplest to construct (and are used by the Tanzania team of EWB-SFP)and here is a good 2006 article on their use: Appropriate Technology for the Treatment of Drinking Water in Roche, Tanzania.

And of course this review would not be complete unless we have an article about our famous Prof. Gadgil, on removing arsenic from ground water - Susan will visit Bangladesh next month.

Measurements and Statistics for Stovers

2006-10-06T09:35:00.000-07:00

Our Berkeley Darfur stove development experience, comparing the efficiency of different designs, indicates that the noise in the measurements of the fuel use will make the clear demonstration of improvements in efficiency difficult – even with a very good testing method (designed just to reduce measurement uncertainties) a difference of 30% in performance between two tests (with different designs and/or cooks) may not be enough to show improvement. The statistical aspects of implementation are non-trivial and deserve plenty of attention, and good data retention practices – save me the data Brian and I’ll try to help crunch it.

In manufacturing we often have the need to compare two “populations” to see if there is a difference – say because the products are made on two different injection molding machines, are made during different shifts or at different factories, or because we are bringing out a new design. Here is how we go through the process, with just enough statistics to do the job:

Develop a procedure – which is a carefully written procedure and a testing station – that seeks to minimize test to test variation, measuring the right things and using what we know about the product’s end application to make the test robust and reliable. For a stove we know that the start up phase is awkward so the test must be long enough to reduce the impact of this, and we know that losses from the pot due to evaporation are a problem because this changes from test to test. So we might decide that boiling more liters of water (a typical cooking surrogate – at this phase there may be no need to duplicate actual cooking, since that test comes later) for a longer time will reduce test-to-test variation. The test should be designed to most easily highlight the differences between a good product and a worse one, so extreme conditions may be considered – in the case of a stove perhaps a consistent wind is used (if this is a realistic condition) since this has been show to differentiate similar stoves.
Analyze the test itself - the basic tool used is the “gauge R and R analysis” – examining how repeatability (the same person, testing over and over) and reproducibility (different people testing) affect the outcome of controlled testing. For this test with a particular stove, several cooks perform the same task several times each, then these results (say time to boil or amount of wood used) are put into a special spreadsheet to mathematically determine how much of the observed variation (ideally there should be none – it is the same stove after all) is due to the testing method and stove, and how much is due to the differences between the techniques of each cook. It’s a challenge, but this kind of approach – technical without being obsessive – may be the way that engineers can help most; in this manner new stove designs and implementation approaches can be clearly shown to be effective and funding agencies can feel that they can invest with confidence that they will get results and people will be helped. Until then, we will only be able to make crude wishful projections about what the potential impact of a project will be – and this is not good enough. More detail on R&R measurements (from NIST) at http://www.itl.nist.gov/div898/handbook/mpc/section4/mpc4.htm but remember that you just have to plug your measurement results into a spreadsheet and the conclusions fall out.
Demonstrate that the testing process is “well behaved” – a test is not good enough if there are too many variables impacting the results We must try hard to make sure that the differences between tests are due only to random variations, such as weather conditions, slight operator differences, random construction variations between stoves, etc. Systematic variations might include gross differences between manufacturing shops, poorly trained operators, or changes in construction materials – these are things that we are testing for (lapse in quality) so the test itself should eliminate their impacts as much as possible… In statistics we say that the test results should follow a “normal distribution” (also called Gaussian http://en.wikipedia.org/wiki/Normal_distribution), so that the variable that is being tested for – say the fuel consumption used for a specific task, such as boiling 5 liters of water for 45 minutes - has a central value that defines an average, and a bell shape due to the random fluctuations about this mean. There are many other types of population distributions (bimodal, etc.), but the normal distribution is the one that allows us to use the mean and standard deviation (and other traditional statistical tools) to describe its mathematical properties. In Excel you use the "frequency distribution" function to separate all your data points (each one is a value for fuel consumption from an individual test) into small ranges (or "bins") and then you plot the range values against the number of test results in each bin (just like in the figure). If it doesn't look like this figure then your testing method needs work for it to be reliable.
Improve the testing if necessary – if the distribution is not normal, or the gauge R&R results are too large (i.e. we can’t reasonably tell if one stove is better than another, even though one should be) then the test must be modified. Examples of changes might be a clearer written procedure, better operator training, or actual test changes (such as narrowing the allowable temperature range in a simmer test or using a longer boil time, to reduce startup/transient effects or brief operator errors). Remember, a poor test wastes time – it may make more testing necessary (so that results can be averaged) or require superfluous testing (like continual testing of the control stove). The goal is the minimum testing that demonstrates the smallest acceptable difference between dissimilar stoves. The results of each individual test must be trustworthy, so that the results are as clear as they can be. The R&R method is well worth the effort – in the case of a 3x3 evaluation (3 operators test the same stove 3 times each – done just one time, just to evaluate the test procedure) it may take 1 day for the R&R but it cuts the new stove testing time in half (because the control stove no longer needs to be tested every time) for the rest of the program life! And regular R&R testing at different locations (such as at Khartoum and Nyala and the IDP camps) eliminates uncertainty about place-to-place testing variations – a real worry when testing is geographically distributed and can only be lightly supervised.

With Brian in Khartoum and now making stoves for Darfur, it is worthwhile talking about new product introduction quality control – there are several ways to make sure that your new stove performs in every way like you designed it to, and you don’t necessarily have to build a fire in each one. In manufacturing we use several statistical techniques to prove within a certain degree of confidence that your manufacturing effort is good. The process goes something like this:

Determine what it is about your stove that makes it work right – tight construction, the right pot gap width, weight (are the right materials used throughout?), time to boil X liters of water (firepower), amount of wood for a specific task (efficiency), etc. You are correlating some few things that says that new stove owners will be pleased, you want to make the correlation as reliable as possible, and you want the measurements be as easy and quick as possible.
For just a few stoves you’ll be handling every one to see if it feels right – if you know how your stove tests well enough then you should be able to tell bad product, but LOTS of stoves means too much handling, so this start up phase is the time to practice inspections and testing. Do sloppy stoves mean bad efficiency and short life in homes? How sloppy is too sloppy? Nothing is perfect so some issues are OK (small gaps, poor joints, etc.) and have to be passed, and others are unacceptable; don’t sweat the small stuff.
Decent measurements might be weight, air gap width using a standard pot (or no pot – just a measurement), and fuel efficiency. Often you can do the efficiency measurement only when you suspect it needs to be tested (new manufacturer, new materials, different city, etc.) – this test is the hardest and has the most error. In any case you should do a gauge R&R of the measurement, to see that the results are normally distributed so that you trust your measurements – how efficient your stove is will be something people want to talk about. Accumulate measurement numbers all the time and they will add up to a good record that someday you can publish to show the stove’s effectiveness.
Set specifications – create some measurements that show obviously that something is either acceptable or not. The stove maker can use them, you can, people in different cities can. Any spec is better than no spec – you can’t talk about quality unless you have even a tiny amount of information on how things vary. The challenge of doing this in strange countries is there, but maybe you will get lucky and everything will be perfect - there is no variation to measure!
The best quality technique is 6 Sigma (http://en.wikipedia.org/wiki/Six_Sigma, and see the section on DMAIC) – only a few defective parts in a million allowed. Here you measure parts even as they are made, so bad stoves are never created. If the parts are handmade and there are weighing scales available, then using can be quick method of checking craftsmanship. And there are lots of variations of 6 Sigma – I practice the “lean” version where the main goal is to eliminate as many parts and operations during manufacture as possible. Less parts = less things to worry about. Under ideal circumstances you do very little inspecting at the end, since why would there be a bad stove? But if you can’t be there while things are made, all you can do is simplify the design, and ask to get the first few asap.
The government and other folks use the AQL method – specifying an Acceptable Quality Level – where there are tables to tell you how many out of each thousand to test, so that you don’t have too many bad stoves (all based on the statistics of a normal distribution). This website http://www.sqconline.com/ lets you plug your desired quality level into a on-line form and it tells you how many stoves to test, but you still have to decide what is an effective measurement. I have used this method but am not excited by it – it assumes that you accept bad parts, and that you don’t have good enough control of manufacturing. And this is true if you don’t have a good enough relationship with your machine shop.
Continuous improvement is always a part of the equation – your first stoves need to be good or people will be disappointed and then you’ll spend the rest of your life answering questions and fixing things. Half of quality is about not wanting to waste time like this. Nip problems in the bud as quickly as possible, bring things to the attention of your stove man and emphasize why problems hurt his chances of future business. Keep reminding them of their defects – details about problems will hopefully keep them thinking about improving. Unfortunately, this is about the time when you need competitors, so that you have negotiating power. Having a second supplier is a great thing, because distributing business between them (even if one is a little more expensive) keeps both on their toes – you can have one make a much smaller percentage, but not having two will cause you problems eventually.

References on stove measurements and performance statistics:

Peter Scott's World Health Organization Indoor Air Pollution workshop presention "Stove Design and Performance Testing" (Uganda, 2005)
Dean Still's "Comparing Stoves and Proposed Stove Benchmarks" (ETHOS 2006 Proceedings, Session 6)
The master UCB web page for modern (March 2006) stove testing methods - the lab WBT, the Controlled Cooking test, and the Kitchen Performance test is here.

Next: Links just on stove implementation experiences from around the world

Berkeley Darfur Stove Project Well Underway!

2006-10-02T09:26:00.000-07:00

After several stove design revisions and a good bit of what we hope is field appropriate stove testing, Brian (the project engineer-on-the-ground) has arrived in Khartoum – let the next phase of the project begin! For those of you who are catching up, LBNL researchers and UCB students have been working on a new wood/biomass burning cookstove for IDP (internally displaced people – a nice name for refugees who still live within their own country) in Darfur, Sudan. I won’t get into the political or humanitarian aspects of the problem here (see earlier posts and the links within them), suffice to say that 2 million people live in mass camps in western Sudan, supplied with food aid by international agencies, but they are not provided with fuel to cook it. The women are forced to hike ever farther away from the camps to find firewood in an increasingly denuded landscape – at serious risk to their security. A single round trip can take 7 hours and several trips a week are necessary. Presently they use mostly simple stoves and “3 stone fires”, which are not inherently fuel efficient – improved stoves which are suited for their environment and cooking situation will not restore their homes, but it would reduce their risk (by reducing the number of trips they need to make) and buy some time until the world can figure out how to get fuel trucked in, so that people are safer and the environment can recover from the deforestation caused by so many people in so small a place.

This research group developed a stove which addresses local needs – it fits traditional pots sizes/shapes, it can be staked to the ground to secure it during their vigorous stirring, the pots are shielded from the both of their wind to improve efficiency, it can be manufactured locally by craftsman metalworkers, and it saves sufficient fuel day-after-day so that the purchase price is affordable. To find ways to make it more manufacturable locally, they contacted Engineers Without Borders – engineering skills and experience were needed to make the implementation on a mass scale more likely. Western engineering methods and tools were then used to adjust the design, but the local materials, skills, tools, and cooking methods were always kept in mind – even the stove testing used actual pots (and onions stir fried in oil – to simulate their local mulah dish) to monitor the efficiency as different designs were evaluated.

Back to the present. Brian will stay in Khartoum (the far away capital, but the only city that has some of the metal working tools needed to see how stoves can be initially built) for 3 months, assessing the situation, developing local contacts for metal supplies and tools, establishing local efficiency testing for quality control of stoves, and diving into the local culture. He left the U.S. with the best information that we could supply him with – stove plans, possible methods of assembly, an assembled stove and several kinds of templates for teaching people how stoves should be made (so that usability and efficiency are not altered significantly), and the best stove testing methods that we know of. His computer contains SolidWorks software models of the stove – one of the tools that EWB contributed – so that he can demonstrate how the stove parts are assembled, what they do, why they are necessary, and he can alter the design as needed. This won’t help him directly in machine shops there, but it is a powerful tool for talking about stove designs and illustrating our approach. But all of this only tries to anticipate what he will find in Khartoum (let alone Darfur!), where we expect that nothing is what we think it is, despite several fact finding trips there to see what the stove building possibilities and use situations are.

Once he shakes of the jetlag and adjusts to the local accommodations and diet, he’ll explore the already identified metalworking shops, find more choices, see how local craftsmen make sheet metal products by hand, see if immediate modifications need to be made because of obvious local limitations (we hope not many – we tried to take many possibilities into consideration), and try and establish how prototype stoves might be made and how much they will cost to produce. Lots of flexibility and patience are expected to be necessary. The latest stove design left without any efficiency testing (it is hopefully just an incremental change to the previous tested design), but Brian has a stove testing lab with assistants there so he has some hands to help him. We tested in Berkeley (and Alameda – I am still trying to remove the soot stains) with simulated Sudan conditions, but how do they really cook there, and how will this change the testing procedure? What size pieces of wood do they use in the camps, can the stoves be elevated for ease of tending or must they be on the ground, and does the WBT adequately simulate local conditions (though it is expected that this will only be used for stove development – field cooking tests are the next phase of the project)? His charter is to start by developing the process for the first 50 prototypes stoves – we can only hope that he can start to understand real implementation in Darfur, where many other stove use questions need to be answered.

How do they feed their fires, how do they view any process of improving the efficiency of precious wood utilization, can their cooking processes be slightly modified just to save wood, will they share stoves between families, what challenges do they face in their lives that may hinder efficiency improvements (Dean Still’s the “sick child scenario” – real cooks cannot just focus on tending fires optimally), what further stove design changes will they ask for, and what do they value in stoves that we can emphasize so that efficiency improvements will not be lost over time.

It is my estimation that the stove design itself addresses some of the wood consumption problem, but just as important is how fires are tended – a program that just seeks to teach the best possible methods (no new stoves) would by itself have a tremendous impact on efficiency. What prevents IDP women from presently selecting the best present methods (copying the most efficient cooks), and disseminating these through the camps – to reduce fuel use on their own? This kind of cultural issue can only be answered by visiting, sitting, and learning. Too much to worry about for right now, especially with the present situation in the camps becoming more volatile, we can only start the process by making stoves available for the cultural evaluation phase – will people use them and will they indeed reduce fuel use? Once this is worked out, expanding manufacturing and working out the dissemination details will come next. I doubt that we will ever be done evaluating the impact of the whole effort (stove design and manufacture, plus effective implementation), and engineers can help with this as well – we are trained to collect data, evaluate it, then solve the problems identified by the analysis.

Next: Testing and Statistics for Stovers

Sheet Metal FES Stove Design and Construction

2006-07-23T00:42:00.000-07:00

The EWB ATDT stove group had a fantastic month, with some teams designing, some making, some assembling, some testing, and some taking new stoves to Darfur, Sudan.

The purpose of this particular post is to educate myself (and preserve the information on the web), and perhaps you too, about Fuel Efficient Stoves (FES) for developing countries. More information is never a bad thing, so ATDT members who want to know a little more deserve a resource. The focus here is on details of metal stoves (a subset of FES) - design, cultural and functional assessment, local resources, quality control, initial introduction, social analysis, continuous improvement, diffusion based on merits, sustainability, benefit analysis, project documentation, etc. Because we have another round of stove design going on right now - to make changes based on more feedback from Sudan - I will start with very design oriented links, and then more general ones will be added for completeness. No need to look at all of these - just the ones that catch your attention.

There have been sheet metal stoves in the past, and the one being developed here for Sudan is special because it has been optimized for the local cooking conditions and culture. To get a glimpse of just how many FES stove types have been named (like butterfly species?) and listed and linked - there are at least two current tabulating sites (numerous older stove pages have gone defunct over the years) that show the diversity of this genus:
http://www.repp.org/discussiongroups/resources/stoves/StovesA_Z.html
or by country: http://www.repp.org/discussiongroups/resources/stoves/Countries/country.html
http://bioenergylists.org/en/stoves

But zooming in to just the very specific arena of metal FES - of course there is a blog just on metal FES stoves! What could be more specialized, the nitty gritty details of home diabetes treatments for cats? Scattered through these pages there are important tidbits of information on every aspect of offering new stoves to people in foreign countries. You know I like a good concise blog...and we similarly find a manageably sized chunk of information on the rest of the web - some of the classic stoves that are in use all over the world include:

A short video of the assembly of a sheetmetal stove (the VITA) that is somewhat similar to the Berkeley/Tara stove is here - everyone should take a quick look at this: http://www.aprovecho.net/stoves/web-content/media/vita/vita.html. Perhaps the original smudged and photocopied notes about the VITA stove (1987), rolling up a pre-cut sheet of steel; he understands the gap!: http://www.repp.org/discussiongroups/resources/stoves/apro/VITA/vitastove.pdf
I am not quite sure what these guys sell, but for some reason they evaluate 4 different cylindrical sheet metal stoves from Niger, Gambia, Uganda, and Kenya http://www.newdawnengineering.com/website/stove/singlestove/ and one even has a price - 250 Rand.
Here is a stove from Finland stove, with very simple (low grate open area) perforated parts:http://www.index2005.dk/Members/nyshobhumy/homeObject. They had the same vision that we do – shipping flat stoves in bulk to be assembled near the point of use.
Here is a truly beautifully first world version of a metal stove! http://www.permapak.net/volcano.htm
A metal Cambodian rice husk metal stove is described here: http://www.reap-canada.com/bio_and _climate_3_3_1.htm
An all metal design that the mind of Jonathan might have developed – but his is even better so he should patent it quick! http://www.pyromid.net/info/index.html and you can even read the manual at: http://www.pyromid.net/support/PyromidManual.pdf
And the word from Eritrea (right to the east of Sudan) is: http://www.punchdown.org/rvb/mogogo/MogogoEval200108.html where from March 2000 to August 2001 the efficient stove program funded by the Eritrea Technical Exchange resulted in over 3000 stoves being installed in 15 villages at a cost of approximately $25 per stove. Could you possibly have a more relevant report title than "Design, Promotion, and Dissemination of Energy-Efficient Stoves"?
Maybe an even better name is "Cooking Options in Refugee Situations", by UNHCR: http://www.repp.org/discussiongroups/resources/stoves/Refugees/CookOptionsRefugeeUNHCR.pdf

Getting a little more specific here, with links just pertaining to metal stoves in Sudan/Africa:

http://www.chfinternational.org/content/general/detail/2927
http://yoomi.bethechange.org/?p=77 – a delightful informal article on evaluating stoves in Darfur by cooking, and the cultural situation there.
A good overview article on selecting metal stoves designs for Mauritania, plus doing the training on the ground (with good photos): www.sunsmiles.org/slide_show Mauri/PhotoWeb/MauritaniaReport.doc
The recent analysis by Prof. Gadgil is here:http://www.darfurstoves.lbl.gov/d/LBNL59540.doc
a good general article on the situation in Darfur: http://www.refugeesinternational.org/content/article/detail/7099/?PHPSESSID=5ce00f92779c166324e1d
Just on the issues of women collecting firewood is this site - supremely detailed and readable: http://www.womenscommission.org/pdf/df_fuel.pdf
An analysis of some aspects of the stove situation in Darfur last fall, by Aprovecho: www.bioenergylists.org/stovesdoc/ETHOS2006/Langol/LangolETHOS2006.pdf

In this post I have sucessfully avoided all mention of technical things like the size of the stove-pot gap, the exact optimal range of the grate "open area", the sensitivity to the grate-pot distance, heat transfer aspects of the different thickness of steel recommended (and the overall mass of the stove), the diameter or volume to efficiency relationship, the possible unimportance of the Biot number, the relative or absolute amount of particulates and CO emitted (and even efficiency details - or at least what method to use when measuring), how to effectively use these stoves in the field (and how to teach people how to use them), maintenace and repair, construction details (Who, how, where, and when?), libertarian assumptions, dissemination dilution and dispersion methods, viral distribution tendencies when provided free, and so on; so far this isstill all just light background reading. And itis possible that no one in history has yet solved many of these problems. But they might have - those of us who do not learn from the past are doomed to repeat it.

Appropriate Infrastructure Development Group

2006-07-12T22:55:00.000-07:00

Check out the work of these appropriate technologists working in Guatamala. We'll hear more about them at our next AT-Team meeting. In the meantime, check out the technologies they've been developing at www.aidg.org.

* picture above is an emergency alcohol stove -- fashioned out of a soda can, fiber glass, and an aluminum baking sheet

Design of Stoves for Use in Developing Countries...

2006-06-02T23:35:00.000-07:00

Many of you may know by now that EWB-SFP has become engaged with efforts to improve the efficiency of wood burning cook stoves for IDP (internally displaced people - "refugees" who have not left their own country) in Darfur, Sudan. As discussed earlier in this blog, the distance that people need to venture to gather firewood is increasing all the time as the surrounding countryside is de-nuded, and this has led to problems that can be addressed by a more energy efficient cooking stove. This project is described at:
http://darfurstoves.lbl.gov/
http://www.lbl.gov/Science-Articles/Archive/sabl/2006/Mar/01-Darfur.html
http://www.chfinternational.org/content/general/detail/2927
and contributions by EWB-SFP are getting underway - the "Tara stove" (an inexpensive sheet metal stove presently produced in India) has been altered by Prof. Ashok Gadgil's team (from Lawrence Berkeley National Laboratory, LBNL for short) to meet the local conditions and needs that they have researched there on the ground. This modified stove design is being tweaked further, even as I write, to make it easier to manufacture locally, it is now in a computer format that allows the design to be examined easily and modified, and we are at the point of manufacturing a few of this latest design so that they can demonstate it again in Sudan soon. And see how it can be further improved for production in small villages in the region.

The purpose of this post is to provide background information for those interested in learning more about the development of improved "biomass" stoves (fueled by wood and other natural materials) all around the world. The efficient stove problem has been well described (environmental, health, security, etc. issues) and researched/documented extensively; so much has been written and is available on the web. I'll try to distill here some of the very best resources into a shorter list than is found at any particular website, with just a few releantv details about each one. Dig deeper into any of these sites and you'll find much more than you want. Trust me, these are the best that can be found in one day with Google.

In these very links you'll find information about designs, calculations, experiences, efficiency testing, etc. for all kinds of stoves for the developing world - the Darfur/LBNL stove is a sheet metal design, and others discussed include masonary ones and those of mixed metal and masonary construction. The stove that we are working on should perhaps be considered as an emergency design - where some aspects have not yet been optimized in the interest of delivering something fast and inexpensively to an area in extreme need. There are severe time constraints if this project is to be started quickly (flexibility is the benefit of small groups), but the design can be expected to improve over time to improve its manufacturability in the local area, reduce the cost, and make it more suitable for the cooking conditions of the local people. It is extremely important to make this technology "appropriate", so we need to learn what resources are available locally and what is needed by the local cooks.

Enough background! My latest favorite general resource is:
http://journeytoforever.org/at_woodfire.html
and many of the links below are extracted from here, in a fashion that emphasizes the stove designs and experiences that might be most relevant to the Darfur need. For example, some very detailed on line design resources (almost book length!) described there include:
http://144.16.93.203/energy/HC270799/RWEDP/acrobat/fd44.pdf - Improved Solid Biomass Cookstoves: A Development Manual, by UN-FAO. 125 pages of great information, all the way up to combustion science, heat transfer, and fluid flow calculations. This is stove science!

Similarly as good (each resource is different, and better than the others in their own way) is the website of the Renewable Energy Policy Project's (REPP) discussion group on Biomass Cooking Stoves:
http://www.repp.org/discussiongroups/resources/stoves/
where you will find loads of photos of stove designs and case studies - look at this first if you want immediate gratification! Four years worth of discussion are archived here.

Within this site there is a vast number of other links, including:

http://www.repp.org/discussiongroups/resources/stoves/Pcia/Design%20Principles%20for%20Wood%20Burning%20Cookstoves.pdf Design Principles for Woodburning Cookstoves, a 40 page discussion of what we should consider when designing developing world stoves. Large section devoted to measuring efficiency, includin sample data taking forms.
http://www.repp.org/discussiongroups/resources/stoves/Grover/paper-grover.htm a careful technical and economic description of an "ultimate stove" design for developing countries, a good general approach.
There are specific pages just on stoves for refugees (simple) and displaced peoples:http://www.repp.org/discussiongroups/resources/stoves/Refugees/CookOptionsRefugeeUNHCR.pdf http://www.repp.org/discussiongroups/resources/stoves/refugee.html
And there is a link to an analysis of the Darfur efficient stove situation (complex for all kinds of reasons - just the cultural aspects are intimidating) that is only 6 months old!:
In fact this particular report (in part authored by the Approvecho Research Center, an AT establishment in Oregon which seems to be a world leader for research into locally made stoves for developing countries) lead me to all kinds of other resources on AT stove projects already ongoing in Darfur, as a result of UN encouragement to implement fuel efficient stoves (FES) on "a massive scale". More links on how the world is responding to this challenge in Darfur in a new post.
They sum it all up with an extensive list of links to organizations working on international cookstove issues, of course including the ONIL stove in Guatemala that EWB-SFP is fond of: http://www.repp.org/discussiongroups/resources/stoves/organizations.html

Max Chen reminds us that this site (and the CD/book offered there) reviews published books on improved cookstoves (and a billion other AT topics):
http://www.villageearth.org/atnetwork/atsourcebook/index.htm

The web almost has too much information! Increasingly specialized sites and discussions hopefully help people find only what they need, instead of becoming mired in excess - even a problem for somewhat narrow topics like AT. Here are some examples of books reviewed in the AT Sourcebook:

Technology, Markets and People: The Use and Misuse of Fuelsaving Stoves
Burning Issues: Implementing Pilot Stove Programmes, A Guide for Eastern Africa
Modern Stoves for All
A Woodstove Compendium - empasizes the role of engineers
Helping People in Poor Countries Develop Fuel Saving Cookstoves
Cookstove Handbook
Testing the Efficiency of Wood-Burning Cookstoves: International Standards
Wood Conserving Cook Stoves: A Design Guide

the books are about far flung places like Africa, Guatemala, Sri Lanka, Nepal, and Java - each country has unique needs and resources, so requires different stove designs.

Speaking of different countries, this site lists an amazing volume of stove information from online discussions over the years - page after page of just detailed stove links, describing research projects country by country (+55 countries)!:
http://www.crest.org/discussiongroups/resources/stoves/Countries/country.html

One of my very favorite NGOs (a major goal of theirs seems to be preserving and transferring the best existing information around the world - to me a most efficient method for change) is ITDG - formerly the Intermediate Technology Development Group but now called Practical Action. If only for variety, take a look at some IDTG sites - over the years they have published some of the best information, in huge quantities:
http://www.itdg.org/docs/energy/EnergyBooklet3.pdf
and their book publishing arm is one of their strong suites - they have many pages of books of interest to us under their "energy" heading:
http://www.developmentbookshop.com/

Stove Maker, Stove User - fuel-efficient stoves in Sri Lanka
Stoves for People - disseminating stove knowledge internationally
The Kenya Ceramic Jiko - a manual for stovemakers
The Stove Project Manual

For those who like wikis this is just an AT one (the stove entry needs to grow - volunteers?):
http://wiki.villageearth.org/
And I can't resist adding this link to the ultimate western world stove research discussion site - for lightweight backpacking stoves only though. Still worthy of note for our work:
http://zenstoves.net/

In summary, I hope that an examination of some of this information will lead you to believe that this Darfur stove project is based on an immediate need which is not being adequately addressed by other aid organizations. The design of the stove, the proposed local production model, the efficiency and measurement approach, the performance in Darfur cooking trials, and the phased approach are meant to improve our chances of meeting real needs by continuously improving the design... and almost all seem like "appropriate technology" for this situation to me. Towards this goal, we expect that all manufacturing of the stove will be near the IDP camps ASAP, so that users can quickly contribute to the stove improvement process.

"Any third-rate engineer can make a machine or a process more complex; afterwards, it takes a first-rate engineer to make it simple again."
E.F. Schumacher, author of Small is Beautiful, and a founder of ITDG/Practical Action

In April reader SL commented on a blog posting here:
Isn't designing appropriate technology of secondary importance to building local capacity to innovate technological solutions to local problems?

I just get tired of these types of programs because they seem to focus on designing solutions to problems that local NGO's understand better than western engineering students.

What is your position on these issues?

I (Charlie) open this topic up for discussion and start it by observing that it appears that the smaller the aiding organization the more likely it seems as if the project will actively seek the input of local people, and try to follow their recommendations. International develoment dollars too often go to western "experts" instead of the local economy, so I believe that efforts like this one - with no ideology, funding or salaries, assumptions and pre-conceived notions, and with a healthy dose of on the ground work to identify the real problems and needs - are an improved way of trying to improve conditions in very local regions. I am a beginner at development projects but have traveled often in places with extremely low per capita incomes. I have seen that happiness has little to do with wealth, and western misperceptions about local conditions (variety of diet, perceived water quality, comparison of sanitation with our standards, living situations, employment levels and cash earnings, lack of modern amenities like electricity, etc.) can lead to development project proposals (and spending) which do not meet the real needs of people. Who are we to try to manipulate their "quality of life" without first being in their shoes? As the commenter implies, local experience is everything - listen to people, live with them if you can, understand their history and available resources, speak the language if that is what it takes, ask about what NGO efforts already have helped and those which have not, and prioritize your ideas of their needs only afterwards. You might find that addressing core issues like very basic health care, food security, and environmental protection (all using local resources) will go a lot further than inserting alien technologies that we think they need. Appropriate Technology projects in particular hopefully tend to work this way. I hope that the Darfur stove project, and all EWB-SFP ATDT projects, will spend extra time on the ground working with local NGOs just so we don't make the most common mistakes.

EWB-SFP Appropriate Technology Design Team

2006-05-29T15:55:00.000-07:00

cookstove project printed references or good starting point-

one of the first postings on this blog mentions the Village Earth website. Or Appropriate Technology sourcebook. Going back to that website I found a large article/book review section concerning "Energy: Improved Cook stoves". And some of the recommended books are available through Amazon.

The Play Pump

2006-05-25T21:54:00.000-07:00

The play pump, very interesting appropriate tech case:

http://www.pbs.org/frontlineworld/rough/2005/10/south_africa_th.html

ATDT New Project Questionaires

2006-04-02T20:34:00.000-07:00

The EWB-SFP Appropriate Technology Design Team (ATDT) is still just getting started, so nothing is "final", but already there are two questionaires ready for groups/people to fill out to propose a project for the ATDT to consider. A "project" is some carefully considered design project need that an organization (either "inside" EWB-SWP or "outside" EWB-SFP) requires to make progress in helping people employ appropriate technology (AT). If a project meets basic ATDT/EWB-SFP requirements then the ATDT will start the process of trying to marshal EWB-SFP's engineers to consider it and help out.

Unfortunately, there is no guarantee that an accepted project will recieve EWB-SFP help - after the ATDT gives it the thumbs up the proposed project may still have problems meeting EWB-SFP needs (such as for financing, organization, or engineering requirements) or EWB-SFP may not be able to find the appropriate resources/engineers to help out. But the questionaires start the process!

For the moment, we don't have a web based method for downloading the inside and outside questionaires (does anyone know how to post Word documents so that they can be downloaded from a blog like this?), but for now you can contact csellers42@yahoo.com to get either one, and/or get a copy of a sample completed form. Your completed questionaire helps us quickly evaluate your need and and our ability to meet it - if your project looks like something that EWB-SFP can help out with, we'll ask you to make a short presentation to us so that we can get a more details. Not every project's needs can be met by a small local organization like EBW-SFP (because this is a young effort, locally based projects may be initially preferred), so we appreciate your understanding if we cannot help you immediately.

"Bridging the Divide 2006" AT conference at UC Berkeley Next Week

2006-04-01T15:47:00.000-08:00

Ken Chow reminds everyone that next weekend is an important Appropriate Technology conference in Berkeley:

Bridging the Divide 2006
http://bridge.berkeley.edu

Check out the website, but here are some quick comments on what it looks like:

- the conference mission statement is "The divide between the world’s developed and less-developed regions has grown more extreme with the expansion of the global economy, resulting in increased economic marginalization for a significant part of the world’s population. As part of its mission, UC Berkeley seeks solutions to this trend through development and deployment of appropriate technologies and business models that address this divide."

- sponsored by the United Nations Industrial Development Organization (UNIDO) and the UC Berkeley Management of Technology Program

- this is the 3rd annual conference

- it starts Friday afternoon (big speakers and reception) and then runs all day Saturday (more speakers and many panel discussions), and consists of all kinds of programs related to improving conditions in the developing world.

- sample discussion topics that might be of interest to EWB members include microfinance, health issues, designing and implementing appropriate technologies, and renewable energy.

- registration is is $150 for the general public, $100 for non-profits, and $30 (negotiable) for students.

The website also include archives from past conferences and descriptions of student projects - snippets about microfinance, water purification, efficient lighting and stoves, electrification, biodiesel, etc. that indicate some of the range of activities taking place in the Bay Area; for AT there may not be any better place to be. Check it out!

ApproTEC/KickStart

2006-03-17T17:08:00.000-08:00

March's meeting will feature two speakers formerly of ApproTEC/Kickstart (http://kickstart.org). Check out their website and read up on the cool technologies they've worked on for villages in Kenya.

Potential project - developing world stove improvements

2006-03-15T19:01:00.000-08:00

The core group (several ATDT people who are willing to meet more often in person - not exclusive, just folks with a little more time on their hands) has been considering how to get the ATDT impact realized sooner - how do we illustrate to people (local EWB members and regional groups that need engineering assistance) what the ATDT purpose is and why/how they can become involved? A potential project that has been proposed involves an efficient stove for developing countries - we know that improved stove efficiency is needed, but what exactly can be done to meet the all needs of the people who might use it? Does it sacrifice space heating to optimize fuel and cooking efficiency? This might be a good example of a project that needs engineering help:

http://www.onilstove.com/default.htm

This stove minimizes environmental impacts by increasing combustion efficiency and thus reduces the need to burn as much firewood, frees up time for (mostly) women so that they can do other things, it improves health by decreasing indoor air pollution, and it reduces the risk of stove burns to children and women - who could ask for more!

Comment on this post if you are particularly interested! In the meantime we will also be seeing how EWB-SFP can contribute.

EWB-SFP Appropriate Technology Design Team

2006-03-01T08:33:00.000-08:00

i had to remove the word doc questionaire from my website. The site has had issues recently and it did not survive the great purge. I will post it and the Sri Lankan review on the FTP site.

feedback from Sri Lankan Orphanage project

2006-02-03T09:39:00.000-08:00

Heather and I presented the first draft questionaire to the Sri Lankan orphanage group. We will summarize the findings, but in the immediate future they want to research or talk to someone who knows about biogas production and composting systems. The contact is Seth (suprseth@yahoo.com)

Questionaire for potential projects

2006-01-26T21:37:00.000-08:00

Max Chen tosses out some ideas for what it takes to evaluate a new project - see his website:
www.oilycog.com/appro-tech-questions.doc
This document is intended to be used to evaluate the needs of present internal projects (e.g. Haiti, Tanzania, Sri Lanka, India), to see if there are AT problems that they need solved. To make this a "live" document that can be added to or modified by others it might be put on the FTP site established by Dave, and/or we can comment on it here on the blog, we can put it right in the blog (instead of linked), or some combination of all three. How do you want to use your blog? Interactive or as a place to shout out to the others?

Particularly for outside projects, where groups approach us for assistance, we need to decide what our interpretation of AT projects might be, and how we are going to use this definition to select potential projects which might be suitable for the Design Team to consider.

Max sez... great resource!

2006-01-26T21:19:00.000-08:00

From Max Chen: for a really good link leading to many, many short book reviews on AT subjects (Grasses—Their Use in Building?):
http://www.villageearth.org/atnetwork/atsourcebook/index.htm
They call this a "guide to practical books on village and small community technology". 1150 publications from international and U.S. sources are reviewed, covering small water supply systems, renewable energy devices such as water mill and improved cook stoves, agricultural tools and implements, intensive gardening, conformal education, small business management, transportation, small industries and other topics. Extensive index. Price and ordering information are provided for each publication. At the very least this might prevent you from buying the wrong book, and it should remind you of the full scope of AT.

Design Team FTP Site

2006-01-24T18:48:00.000-08:00

I have created an FTP site for file sharing for the design team. Any files you would like to share with the group, please post them to this ftp site. Please keep the site clean and create appropriate folders for different subject groups so that the ftp remains useful. Login info:

host: ewbwestcoast.org
user/pass: contact Charlie or others
If you don't have an FTP program already, I recommend Filezilla

Dave

2006-01-16T10:33:00.000-08:00

Since the topic of refrigeration came up at the last meeting I have a copy of a very good primer on the subject. Refrigeration for Pleasureboats covers in detail how small refrigeration systems work and how to design them. Since almost all refrigerator/freezer systems on boats are custom designs you have to know how to design the box and choose the correct components. This is applicable to the home refrigerator and if you want to know how to increase their efficiency knowing the basics is the starting point.

If anyone would like to borrow it I can bring it to the next meeting.

Some Sources, by Pat Coyle

2006-01-15T12:33:00.000-08:00

(from 11/11/05 email to team)

Most will have seen this content before, but I wanted to try the blog.

Looking at the reading list at Toby Hemenway's site, http://www.patternliteracy.com/reading.html, then looking at titles on Amazon (look for the details using their new "search inside" feature for excerpts, the TOC, index, etc.):

Guide of Appropriate Technology
by Barrett Hazeltine ,
At $70, it is just a bit pricey, but youcan preview it.
This is worth looking at in terms of the lists of types of technologies. It also addresses cultural, social,and business aspects.

There is also:

Appropriate Technology: Tools, Choices, & Implications
(Academic Press Series in Engineering)
by Barrett Hazeltine
It is older, '99 vs 2003; but about $27

I also think I found the title I asked about, the "Red R Book", it has emphasis on relief worker's being able to respond to engineering issues:
ENGINEERING IN EMERGENCIES - A Practical Guide for Relief Workers
Jan Davis & Robert Lambert

Looking at EWB projects, I found a link to CSM's http://humanitarian.mines.edu/ and then to

http://www.mondialogo.org/engineering-award/?&L=en
Where there is a description of the MONDIALOGO ENGINEERING AWARD: Mondialogo is looking for students who want to apply their knowledge and expertise in order to improve living conditions in developing countries on a lasting basis. With the Mondialogo Engineering Award we are challenging young engineers and technologists to enter into an intercultural dialogue and to find solutions for a better world.
The list of winning projects is an interesting cross section and they will be doing 2005/2006 call for proposals, so it may be of interest.

Finally, if you might be interested in the invitation for open source approach to educational, demonstration, sustainable development operation based on 40 acre Belize property, you can check it out at: http://belizeopensource.jot.com It presents a number of appropriate technology decisions that will need to be made. (I am going to migrate it to belizeopensource,org but not much there yet)

Pat

Aqua Sun Portable Water Purifiers

2006-01-12T18:22:00.000-08:00

Here is some information on the Aqua Sun portable water purifiers. There are 2 models, the PWP-C with a solar panel and the PWP-V without a solar panel. These were designed for groups such as EWB teams who need to bring in the means to make potable water for their own use. Aqua Sun also makes several models of fixed water purifiers for larger applications.

The wholesale/dealer prices are $1500 for the PWP-C and $1300 for the PWP-V. This includes a 2 year replacement parts kit.

Check out their web site for some interesting case studies, partnerships, and history of the company.

I wanted to put a table here with the specifications of the unit but the blog does not display the table correctly once it is published, so go here to see the table on the Aqua Sun website.

Excellent AT Stove Link

2006-01-10T11:52:00.000-08:00

Every once in a while there is a great link out there - the Internet has tons of information but too much of it is useless. This is a great one just on appropriate technology for stoves:

http://journeytoforever.org/at_woodfire.html

It covers everything imaginable - efficiency, indoor pollution, different fuels, environmental costs, etc. And if you include the many links in it, it is a huge amount of information from a zillion sources. If we had more resources like this we would be rich - then when we encountered specific needs in the field (water purification, irrigation, microcredit, livestock, food security, etc.) we could see what has been done and then customize a solution with our engineering skills. For example, most of the stoves described have not been fully developed - the job is not done until they are reliable and you can manufacturer them efficiently and inexpensively in developing countries. And what might be "appropriate technology" in one country may not be in another.

LBNL Seminar on Efficient Stoves in Sudan

2005-12-12T08:58:00.000-08:00

If anyone is interested in Ashok Gadgil's work on fuel efficient
stoves in Sudan, there will be a seminar next week at Lawrence
Berkeley National Lab (LBNL), Dec. 13, 1:30PM. LBNL is located just up
the hill from UC Berkeley in Berkeley. Access is fairly easy. There
are shuttle buses from Berkeley BART, but you need to get on the
visitor list, so don't wait until the last minute, if your plan to
come. See posting below for details.

Howdy

You're invited to attend this Environmental Energy Technologies
Division seminar taking place from 1:30 to 2:30 PM on Tuesday,
December 13th, in LBNL Bldg. 90, Room 4133. (Please note the unusual
time and location of this seminar.)

TITLE: EETD's Mission to Darfur

SPEAKERS: Ashok Gadgil (Indoor Environment Dept.) and Christina
Galitsky (Energy Analysis Dept.), both with EETD

DESCRIPTION: We will describe preliminary findings from our recent
field trip to Darfur, Sudan, where we aimed to introduce fuel
efficient stoves to the internally displaced persons (IDPs) camped
there. There are 2 million IDPs in Darfur refugee camps, with another
200,000 across the border in Chad. We visited two camps in South
Darfur, Otash and Kalma -- the latter is the largest camp in the world
housing more than 100,000 refugees. With our improved stoves we
demonstrated fuelwood savings of about 50%. The talk will describe the
background and the goals of this visit and our technical and field
impressions along with illustrative slides.

For further information about this seminar please contact Hugo
Destaillats at (510) 486-5897, or send e-mail to HDestaillats@lbl.gov.
Visitors from offsite who plan to attend and will need gate access and
parking arrangements, or who need information about riding the LBNL
shuttle bus should contact JoAnne Lambert at (510) 486-4835, or send
e-mail to JMLambert@lbl.gov.

Some Useful Links

2005-11-30T16:08:00.000-08:00

There is nothing as bad as a crummy web link, but there is nothing as satisfying as a really good one - it can take you places that you have never heard of, where you can learn things that you only imagined. These links have been tested extensively and they either point directly to useful Appropriate Technology information or they point to someplace useful in other ways (e.g. a source of good links). I promise. Feel free to post your own favorites (its nice if you provide a little info with each), or send me individual ones and I'll group them all together into a master list.

http://www.i4at.org/library.html#water – Institute for Appropriate Technology (USA)
http://journeytoforever.org/at_link.html - Intermediate Technology Development Group
http://www.itdg.org/ - the group Practical Action (formerly ITDG)
http://livelihoodtechnology.org/ - more ITDG resources on intermediate technology
http://www.alternative-finance.org.uk/en/ - ITDG’s microfinance literature resource
http://www.itdgpublishing.org.uk/ - more ITDG, they are distributed all over the web
http://www.developmentbookshop.com/ - even more ITDG! Good book title resource (
http://www.researchinformation.co.uk/apte.php - Appropriate Technology magazine
http://www.farmafrica.org.uk/ - FARM Africa, farmer assistance group
http://www.mamud.com/ - ethnovetrinarianism, agroforestry, food security in Africa
http://www.yearofmicrocredit.org/ - International Year of Microcredit 2005
http://www.foodsecurity.net/ - Food Security Network (news articles)
http://www.fao.org/spfs/ - FAO’s Special Programme for Food Security
http://topics.developmentgateway.org/foodsecurity# - Development Gateways’s page on Food Security
http://www.eldis.org/ - Eldis (UK), sharing information on development
http://www.ifad.org/media/success/index.htm - success stories from the International Fund for Agricultural Development (UN)
http://www24.brinkster.com/alexweir/CD3WD/index.htm - 680 MB of downloadable documents on 3rd World development (many topics)

Photo: Wood and stone constructed, water powered grain mill - one of the very few uses of the wheel in the mountains of Nepal.

How to Use this Blog

2005-11-29T20:48:00.000-08:00

Blogs are beautifully easy to use - just come to the blog, click on the Blogger icon in the top left corner, type in your password (this keeps blog spammers from interfering with us), select "create" a posting, and start typing. We'll start off with the basics (just cut and paste things into the space), resulting is a linear look, and then we will improve on it - with links to other webpages grouped together if that is appropriate, other pages off the main one for special topics, and so on. There should be a way to post just about any type of information, but sometimes we'll have to figure it out. For now try posting things like good web links, books that you feel are appropriate (add a little review of them), questions or comments for the group, photos, announcements (upcoming events, etc.), and more. A blog is only worth having if you use it regularly. If you wish use the "edit HTML" option to fine tune your posting, and always feel free to post photos using the photo icon. Look at other blog pages (including their HTML code) to see what is possible and effective. One of mine is http://travelswithcharlie.blogspot.com/. Blogspot has information on how to improve your technique as well.

If you want to become a "member", so that you can post, or if you have comments or questions email me (Charlie Sellers) at csellers42@yahoo.com

Photo - the streets of Vientiane, capitol of Laos.