Sam Redfield on Pico-hydro at La Florida
by Catherine LaineJune 29th, 2008
The pico-hydro system we’re working on just got featured on MAKE and Gizmodo so I asked Sam Redfield, the primary developer on the project, to send over some more info on his invention and time with us in Guatemala.
I recently returned from a 3-month stint with AIDG Guatemala. As part of their program in Central America, they are pursuing an ambitious project to develop cheap, small hydroelectric systems under one kilowatt known as Pico-Hydro. Prior to my arrival in Guatemala I had developed a small hydroelectric system housed in a 5-gallon bucket. Using a Permanent Magnet Alternator as the generator in the system and made almost entirely of PVC, we conducted field tests in the small community of La Florida to determine what the possibilities were for generating power with the device. La Florida had lost its primary source of electricity and was depending on candles and batteries for their energy needs.
La Florida is a small community based around a coffee plantation on which a group of landless campesinos ceded from ruin after the previous owners abandoned the property. It now runs as a collective producing excellent organic coffee. Set in the foothills below a semi-active volcano near the Pacific coast in the tropical lowlands of western Guatemala, La Florida offered a temperate climate with easy access to water. Our work in la Florida focused around the prospect of charging cellular phones using the Pico-Hydro system that I had developed in the States.
Charging 11 cell phones off the battery
To charge cell phones, members of the community have to take an expensive and time consuming taxi ride an hour each way to pay a service for charging. Cell phones have become increasingly important in small isolated communities as they give these communities access to medicine, the market and family. Our field tests began by identifying a site with access to abundant water and a steep incline for the pipe to feed the generator. After a site was identified, we laid the pipe and tapped into an existing stream. In all we laid 80 meters of 2- inch pipe to achieve a head, or drop in elevation, of just under 30 meters.
The generator was then installed with a voltage regulator, car battery and inverter. The regulator insured that the battery was not overcharged, the battery stored the energy for use and the inverter bumped up the power to 110 volts. Three power strips were then attached to the inverter. After we determined that the generator was producing electricity, we began gathering cell phones from the community. In all we gathered 18 phones. The generator was producing 60 watts, not a whole lot of power, but enough to charge 10 cell phones at a time without depleting the battery. Because the car battery could remain fully charged with a load of ten cell phone chargers working, we would be able to charge ten cell phones at a time 24 hours a day without depleting the car battery. Alternatively, we could charge considerably more cell phones simultaneously and allow periods for the car battery to recharge. The system produced enough power to charge all the cell phones in the community and potentially could provide a service that would save the people of La Florida considerable time and money.
Micro-enterprise schemes are being investigated to provide an individual with the generator as a business venture. The owner of the business would charge a small fee for charging cellular phones that would be affordable. The cost of the generator would be paid back over time with the proceeds of the charging service. Another application of the generator being explored is for household lighting. With the emergence of high output super efficient LED’s the prospect of creating small-scale lighting utilities is within reach. Again, people would be charged a reasonable fee to receive four to six high output LED lighting fixtures in their homes. The provider of the service would make a modest profit, and pay for the generator over time.
Duration: 1min
Work continues. One of the issues that we face in deploying the system is cost. The Permanent Magnet Alternator that generates the electricity in the system costs more than $300.00 US and has to be imported from the States. As part of my program with AIDG in Guatemala, I investigated the possibility of rebuilding a Toyota alternator to function as a Permanent Magnet Alternator. After investigating several possibilities, I am happy to report that we now have a working prototype, which is being integrated into the system. Other improvements include integrating the voltage regulator into the device and improvements in turbine performance. In the coming months trials will continue and no doubt improvements in economy and performance will be made. My work with AIDG Guatemala was invaluable to me in understanding the energy issues people face in the developing world and provided me an excellent opportunity to develop my technology in an environment that fosters innovation in a setting where people’s lives are positively effected. Thanks AIDG!
-Sam Redfield
Update:
Sam is building a generator for Professor Brian Thomas at Baylor University to be installed in Honduras as a cell phone charging micro business.
He’s going to try to get me a parts list with general specs to post on the blog in the next few days. Until then if you have pressing questions, you can email him a samredfield [@} earthlink {dot] net
More info:
Wind Stuff Now Gm Alternator Mod
Related Posts:
Update: Parts List. Manual Coming Soon.
Communities We Work With: La Florida (Guatemala)
12 Days of Xmas - 10 drops a dripping
12 days of Xmas: 5 cell phone rings
Link of the Day 042308: Human Centered Design for the BOP [NYTimes]
Letter to Inverters R Us
June 29th, 2008 at 4:33 pm
Awesome job, folks! This kind of story makes my day!
June 29th, 2008 at 9:18 pm
Splendid work! If, as described, you have a battery in the system to energize the field coils, would you need a permanent magnet alternator? Also, what is the potential for microcredit entrepreneurship here in order to increase financial self-sufficiency?
June 30th, 2008 at 4:28 am
Hi, do you actually need to convert from 12volt to 110? most cellphone chargers do need only a fraction of 12 volts. I am not a technical type, so please bear with my “stupid” question.
June 30th, 2008 at 6:49 am
Fantastic idea people.
Nice to see technology being used for an honest cause.
Keep up the good work.
June 30th, 2008 at 3:23 pm
i agree with elkin. most phones that use a usb port, only require 5v at 1A, peak. it seems like all that is necessary is some rectifying diodes and a buck converter chip, to avoid the use of a power inverter (120ac). maxim-ic makes some awesome dc-dc converter ic’s check em out:
http://para.maxim-ic.com/en/search.mvp?fam=dcdc_all&tree=powersupplies
-Dane
July 1st, 2008 at 2:31 pm
I’ve been reading on this from multiple sites for a few days now - it sounds pretty darn cool.
One thing that I suspect, from some alternate reading, is that the lid of the bucket turbine needs to be securely fastened? Is that correct? My thinking is that is how they build up the pressure to leverage the drop?
Without sealing the lid, you basically lose the pressurization of the system, and you’re not going to get more juice than you would from a perpetually refilled 5 gallon bucket, correct?
By keeping the lid sealed, you can basically increase the pressure of the bucket, so that 30 feet (or whatever) of the water pressure is leveraged?
Yes, no, maybe? Back to physics class for you, infidel?
;)
Thanks - great concept and social cause though!
July 1st, 2008 at 4:21 pm
Great design. We live on a property with a small stream, but one that would easily fill a 2 inch pipe. A question I have is whether one needs a full 30m drop or whether one could get a 15 m drop and just have batteries charge up more slowly.
Another question I have is whether one can design a storage capacity based on 220v. We have a water pump for our well which is based on 220 AC, which, in addition to lights, would be the main use for such a device should the power go out.
July 2nd, 2008 at 1:44 am
Lose the inverter! Double your power.
July 2nd, 2008 at 10:03 am
I would buy one in a heartbeat !!,especially if it was wind run,might you consider them as a possible saleable item in the US ?.
July 2nd, 2008 at 11:44 am
I would REALLY like to see a photo of the underside of the lid on that bucket! :) Pretty please!
July 7th, 2008 at 12:33 pm
More photos are in the AIDG flickr group
http://flickr.com/photos/aidg/sets/72157604349207990/
July 8th, 2008 at 7:14 am
If you used cigarette lighter mobile phone chargers then you could go straight from 12v without having to worry about the exact voltage each phone requires.
@MO’B, I don’t think the bucket is pressurised. Looking at the picture of the turbine, it looks like it is an impulse turbine. torque is generated by fast flowing water hitting the turbine blades and pushing them round, rather a pressure drop as fluid flows through the turbine providing torque (a reaction turbine)
Dan
July 15th, 2008 at 5:48 pm
Great post. Partially re-blogged @: http://www.echoinggreen.org/blog/micro-generation-blog-roundup
July 25th, 2008 at 2:37 am
I am living in Costa Rica. Right next to my house is a water overflow tube which is about 12 inches in diameter which runs (from the mountain above) rain or shine. The volume of water that comes from this tube sounds like I have a large river next to my house! I would LOVE to figure out how to harness the energy from this overflow but can’t seem to find step by step instructions anywhere. I know nothing more than the absolute basics of hydroelectric power and if someone could direct me to (or post) a resource for plans and materials that would be fantastic.
Thanks!
August 4th, 2008 at 10:55 pm
I’ve been trying to find specs on this, but have basically pieced most of it together from the many blogs and pics. I thought there was a reservoir inside the bucket also, but that was just to house the alternator/motor.
The main pipe is split to 4 seperate pipes that feed all the way to the bottom of the bucket. Each end is angled to best hit the turbine on the bottom.
Housing everything in the bucket is quick and easy and keeps the electronics out of the rain.
I’m trying to work out a more universal model to take with me when I go camping, to power a light, radio, or something like that.
Camping near water isn’t really a problem, but getting enough drop to provide power might be depending on the design.
August 20th, 2008 at 7:01 am
Hi there,
a couple of years ago I visited North Vietnam. There almost everyone used a watergenerator (miniature watermill hanging in de streams) for minimal electricity. Sometimes they had linked more than 100 metres of old electricitywire going up the hill to a small bicyclebulb for light. These contraptions could be bought in some places for less than USD 50,–
In other words it might be cheaper to import from Vietnam than to develop it yourself. The name used is pico-hydro. Further information can be found http://www.winrockindia.org/newsletter_pdf/Resource_Vol29_Dec06.pdf
Good luck
August 25th, 2008 at 8:41 pm
Very cool. I’d love to see an urban version designed to fit onto the on rain gutter downspouts. Perhaps it will eventually be cost effective enough to be a practical add on to solar.
January 27th, 2009 at 10:30 am
Hi,
I’m a design engineering student from Glasgow University, Scotland. Our current team project is to develop a pico hydro power system (to fit in a drainpipe!). We are very interested in your design. Could you give us any ideas on ways we could make this on a smaller scale? Our flow is relatively slow (about 2 litres per second).
Many thanks,
Anna
May 4th, 2009 at 10:21 am
i was excited about the project . it’s job well done. i am happy because it offers me some ideas on my very similar project that i am presently working on. i will mind having a sketch of your design on the turbine.
Thanks a million
seyi
June 7th, 2009 at 1:57 pm
I’ve been using microhydro for the past 18 years. It works great. I am planning to replace my Ford alternator with a permanent magnet alternator which will save the need to replace brushes or rebuild annually. The following is the manufacturer of the system I’ve been using: http://www.microhydropower.com/
I have a large battery bank & use an inverter to supply 110 to the house. I have freezer, internet, Satellite TV, washer, table saw, power planers etc. all running thanks to my microhydro.
July 30th, 2009 at 3:12 am
Magnets on the OUTSIDE?
Hmm. Would be wizer to have the magnets ‘locked’ INside a ‘ring’, imho
if this thing starts turning fast, and 1 magnet comes loose…. i would not want to be standing near to it.
If you place the magnets inside a continues metal ring, the faster you turn, the more the magnets get compressed AGAINST the ring. More solid design. I think.