Last fall we were very fortunate to get funding from the Lemelson Foundation to support our tech development and business incubation work. Lemelson is very interested in supporting new inventors in the US and developing countries and helping with the diffusion of technologies that improve people’s lives. Their grant is allowing us to form partnerships with companies and university groups designing for the bottom of the pyramid. Just a few weeks ago one such group from the Michigan State University came to work with us in Guatemala on solar refrigeration. Eric Tingwall, a mechanical engineer and freelance writer, writes about the team’s experience.
Mechanical Engineering team from Michigan State University at AIDG Guatemala working on a solar refrigerator
With unreliable or nonexistent electricity infrastructures, rural regions of developing countries often have high vaccine spoilage rates. With no way to keep vaccines cold over an extended period, these medicines sometimes must be administered within 48 hours from the time they’re put into a vaccine carrier for delivery.
On March 8, six mechanical engineering seniors from Michigan State University arrived at the AIDG Guatemala workshop as part of their work to address this problem. Working with the Appropriate Technology Design Collaborative, our goal is to develop an affordable, robust refrigerator that uses passive solar energy to maintain temperatures from 2°C to 8°C. The end goal is a set of clear manufacturing plans that will be posted online in an open-source format, free for anyone to access.
Filing Steel
Building the solar collector
Since we wouldn’t have electricity to power our fridge, previous Michigan State teams directed us away from compression refrigeration and pointed us to adsorption refrigeration. The Internet is stacked with academic knowledge on solar adsorption refrigeration, but our team has the goal of developing a system and assembly instructions that can be used by anybody. Our adsorption refrigerator design uses passive solar energy rather than electricity and has no moving parts. But before the adsorption process can be understood, it is necessary to understand the basics of refrigeration. All fridges operate on the principal that a liquid boiling to a gas takes heat away from its surroundings. It is also important to know that a liquid can be made to boil at a very low temperature by altering the pressure. While water boils at 100°C at atmospheric pressure, it can be boiled at 0°C under a very high vacuum.
A refrigerator operates by allowing the refrigerant to boil at temperatures as low as the desired cold space temperature. Eventually, the evaporated refrigerant must be condensed back to a liquid to repeat the cycle for continued cooling. While a typical home refrigerator relies on an electric condenser to turn the gaseous refrigerant back to our liquid, our system uses chemical processes to drive the evaporation and condensation of the refrigerant.
CAD drawing of solar fridge design
Previous Michigan State teams working on this project directed us to use ethanol as a refrigerant, since it is almost universally available and nontoxic. While pure ethanol may be difficult to find in developing countries, liquor with high alcohol content can be used in its place. As our ethanol boils, it is adsorbed by activated charcoal, a porous solid that is often used in fish tank and drinking water filters to remove impurities. In our refrigerator, the activated carbon allows the system to maintain a constant pressure as the ethanol evaporates. When the sun heats our solar collector and activated charcoal bed in the middle of the day, the heat causes the release of the adsorbed ethanol. The raised pressure and condenser cooling allow the ethanol to return to a liquid state so it can be evaporated again to cool the refrigerator.
Our trip to Guatemala was intended to be a learning experience – an opportunity for our team to understand what materials were available in developing areas and what challenges would slow manufacturing. The team faced issues with material availability, manufacturing capabilities and power outages, but was still able to complete the build in less than three days. Our final product uses a simple cooler fitted to a system of copper pipes and connected to a steel solar collector, held in a wood frame. With just one day to test the device, we recorded our lowest temperature at 1.3°C.
Back in East Lansing, Michigan, we still have several weeks of work to refine the design, complete testing and compile our final instructions for manufacturing. There is also significant room for this design to evolve, especially in regards to cost. Currently, the device costs in the range of $400 to $500 for one-unit manufacturing. One area for substantial cost reduction is the activated charcoal. While the team currently buys activated charcoal at a cost of $200 per fridge, it can be made simply by burning coconut shells in a controlled environment.
Michigan State University Team and AIDG crew
The solar adsorption refrigerator project is sponsored by the Appropriate Technology Design Collaborative with the financial support of the Lear Corporation and Chrysler Foundation. The project is part of the Michigan State University Mechanical Engineering senior capstone class. The spring 2009 team members are Nabeel Aslam, Kevin McPhail, Ryan McPhee, Brent Rowland and Eric Tingwall, guided by faculty advisor Dr. Craig W. Somerton.
Sam Redfield, Project Manager of AIDG’s pico-hydro program in Guatemala was just accepted for MIT’s International Development Design Summit in Ghana this summer! Here is an account of some of his work at our new facility in Guatemala. Keep an eye out for the build manual he is producing for the Five Gallon Bucket Generator!
Hi everyone. I’m back in Xela, home of AIDG’s offices and research facility in Central America. Big things are happening down here. This January we moved into a beautiful new compound. Rising above the neighboring buildings, the new office resembles a pagoda. Its red corrugated roof flanking three stories of golden clapboard walls is something of an enigma in a neighborhood dominated by low concrete block houses. In addition to much needed additional office space, we now have a new fabrication shop, electronics and water lab and, under construction, housing to accommodate several interns and visiting researchers. The new office is full of light and the staff and interns that work here are noticeably happier with the new work space. In what can be chilly mornings in a city perched at roughly 7000 ft., it’s nice to work in a place where the brilliant morning sun comes in through the windows and warms the space.
I have returned to Xela to continue my work on the pico-hydro system that I field tested in La Florida last year. Pico-hydro systems are small hydroelectric generators that produce less than one kilowatt of power. We are looking at using the generator to provide basic lighting, cell phone charging and ultra violet water purification in under served communities. Housed in a five gallon bucket, and employing a modified car alternator driven by a turbine, the generator promises the potential of cheap clean energy to those without access to the electricity grid.
Pico-hydro test in La Florida in 2008
The Permanent Magnet Alternator
Last year, we established that the generator was viable as a single point power source that could be installed quickly with limited resources and could produce consistent power with modest water usage. Still unresolved were issues of cost, longevity of service and overall performance for electrical output. The generator was built using a rather expensive modified GM alternator produced in the States for the home brew wind turbine market. This modified alternator, called a permanent magnet alternator (PMA) produces energy at low RPM’s and works well in small-scale hydroelectric systems. In addition to the price, (more that $300.00 U.S.), the alternator would have to be shipped to its destination country, adding additional cost. The PMA was by far the generator’s most expensive component and the only element in the system that would need to be imported, so we looked to it to reduce the generator’s overall cost.
My solution was to modify the Nippo Denso alternator produced for Toyota’s 22R engine. They key was using low-tech mods that could be cheaply and easily reproduced in a basic machine shop. The Nippo Denso alternator, found in most Toyota pickup trucks and many sedans in developing countries, might just be the most common alternator in the world. They are often shipped to developing countries to be rebuilt for the market in the US and other developed countries. Where in the States these alternators are simply replaced with rebuilt alternators when they fail, in developing countries there is extensive infrastructure to rebuild them. They are available in quantity in Guatemala and are cheap.
My design for the Toyota based PMA uses only the alternator casing and the stator (the wire coils that surround the rotor inside the alternator). For the conversion, the rotor is completely rebuilt with powerful neodymium magnets and the stator is rewound with thinner gage wire. Non-functioning Toyota alternators can be had for about $20.00 US in Guatemala if bought in bulk. The magnets are the only part of the new alternator that may need to be imported.
Left: Rebuilt permanent magnet rotor. Right: Toyota rotor.
Toyota based permanent magnet alternator
Our new hydro test bench
Last year we lacked the facilities to do extensive testing of the PMA and could only determine that, yes, it worked and that it produced energy at low RPM’s. But we couldn’t determine which gauge windings of the stator would produce the most power given the bucket generator’s RPM ranges. We needed more controlled study conditions, particularly as field tests were difficult to repeat (distance to test site, variability of water flow, etc.).
This past month, we set up both a hydro and a PMA test bench. The hydro test bench simulates the head and water flow rate that determine the output of a small hydroelectric system. By varying the head and flow in the test bench, we can simulate the various conditions under which the bucket generator operates and rate its performance under different loads.
Bucket generator connected to hydro test bench
We can’t directly measure the RPMs of the bucket generator when it is hooked up to the hydro test bench, but we can estimate this number using the PMA test bench. Simply put, we find the number of RPMs in the PMA test bench that replicates the current produced by our bucket generator in the hydro test bench, and thereby get an estimate of the bucket generator RPMs. Using the PMA test bench we can only investigate which windings offer us the highest current at the appropriate RPMs for the system.
PMA test bench
Direct comparison of the GM and Toyota PMAs is difficult due to differences in configuration, size and layout of the 2 systems. That said we were able to determine that the Toyota PMA offers performance in the same general range of the GM system and at a fraction of the cost. If manufactured in bulk, the Toyota PMA would come in at around $120.00 U.S. and the entire bucket generator could cost about $160.00 U.S.
Currently, we are trying to determine which wind of the Toyota PMA will give us the maximum current at the RPM ranges of the bucket generator system. At our maximum available head on the test bench, about 90’, we were able to produce over 1,200 RPMs and 90 watts. We expect to get more than 100 watts in the field at slightly higher heads. We don’t know yet what the maximum output will be.
This spring, we’ll be installing at least two of the bucket generators in Haiti to power ultra violet water purification equipment. A portion of the funding for this project was generously provided by St Peter’s Church in Weston. AIDG’s Haiti office is partnering with local NGOs, including our good friends at SOIL, to address the lack of clean potable water in their service areas. Each ultra violet purification device draws about 30 watts. With the generator, we expect to be able to power three or more UV devices at 100’ of head and 50 gallons a minute of flow. Currently, sites surveys are being conducted in Haiti to determine head and flow conditions and find suitable sites that provide year round consistent water. These long term test sites will provide data on performance as well as service and maintenance needs of the system.
We all know there is an economic crisis going on and that people are having to cut some of their expenses, including donations to charities (sniff!). This all means that we need more help from people like you to keep our programs going strong. But why not make it a little spicy.
A simple proposition
We’re looking for volunteer fundraisers to help us raise the money to continue our work in Haiti and Guatemala. In appreciation for your time, energy and enthusiasm, the top fundraiser gets a trip to Guatemala to visit AIDG’s international office hub “”where sustainable development is put to action”!
Interested fundraisers will receive an information pack with all the details. You must have a phone and internet access to participate. This fundraising campaign begins April 15th, 2009 and ends December 31st 2009. Contact volunteers@aidg.org to request the information pack and please include a bit of information about yourself.
Fine print: The minimum for “top fundraiser” qualification is $3,500 and this is NOT a paid position.
Although most nonprofits pay lip service to collaboration, many of them really see other groups as competition for scarce resources. But highimpact organizations help their peers succeed, building networks of nonprofit allies and devoting remarkable time and energy to advancing their fields. They freely share wealth, expertise, talent, and power with other nonprofits not because they are saints, but because it’s in their self-interest to do so.
Taking this lesson to heart, AIDG became one of the founding members of ANDE, the Aspen Network of Development Entrepreneurs in early 2009. ANDE, housed in the Aspen Institute, is a member-driven organization of NGOs, venture funds, and foundations dedicated to the creation and growth of small and growing businesses (SGBs). *** Jargon alert***: the previous term was SME or small and medium enterprise. I haven’t a clue why the switch to SGB was necessary.
ANDE was launched to deal one of the major issues effecting the success of organizations working on “development through enterprise“.
The true constraint to growth of capital and assistance for SGBs is the gap between investors with capital and funding for technical assistance and the opportunities on the ground in emerging markets. ANDE is, in part, a collective effort to bridge the gap. The amount of capital and technical assistance made available to SGBs has grown rapidly. We have identified an estimated 150 organizations providing approximately $4 billion in capital and services to small and growing businesses in developing countries
The membership fee was steep to weed out pretenders, but the benefits are huge. The biggest is that it enables increased collaboration between groups working toward the same general goal: to help entrepreneurs in developing countries “generate much needed employment, and in the process, address critical social and environmental problems in the developing world”.
Xela Teco, a small manufacturer in Guatemala, worked with the Boston-based nonprofit Appropriate Infrastructure Development Group to develop a better design for a wood burning stove that uses 50% less wood and funnels the smoke out of the home through a chimney. It sells for around $150; the payback on the stove is about one year, since it can cut in half the average $25 families spend per month for wood.
4th Annual Tufts Energy Conference “Global Green Infrastructure: Powering the 21st Century” Date: March 28th, 2009 Time: 9am - 5pm Location:
Sophia Gordon Hall
Tufts University
15 Talbot Avenue
Medford, MA 02155
09:30 - 09:45
Welcome and Introduction by Sherman Teichman, Director of the Institute for Global Leadership (with introduction from Peter O’Regan, Conference Co-Chair)
10:00 - 11:30
Panel 1: Innovation and Diffusion of New Infrastructure Technologies
Theme: This panel is an examination of efforts to both finance and develop technologies that allow us to use power more efficiently and sustainably. It brings together the science and technology of infrastructure development and explores the future of new technological innovation and diffusion.
Confirmed:
• Jon Karlen, Flybridge Capital
• Rob Pratt, EnergyClimate Solutions
• Philip Guidice, Commissioner Mass Department of Energy Resources
• James Bickford, Draper Labs
• Richard Larson, MIT
11:30-11:45
Coffee Break
11:45-12:15
Opening Keynote: Peter Droege, World Council for Renewable Energy
12:15 - 1:30
Panel 2: Revitalizing National Infrastructure
Theme: This panel will explore the future of U.S. Infrastructure policy. What role will the U.S. Federal government, state governments, utilities, and other actors play in the future of U.S. Infrastructure policy? How can we alter our grid to encourage more sustainable power use? Is distributed generation a better means to greener power supply and usage than grid-based infrastructure?
Confirmed:
• Watson Collins, NE Utilities
• Suzanne Watson, American Council for an Energy Efficient Economy
• Alan Nogee, Union of Concerned Scientists
• Penny Conner, NSTAR
• Professor Bill Moomaw, Tufts (moderator)
1:30-3:00
Networking lunch with keynote Gregg Dixon
3:00-4:00
Panel 3: Powering the Developing World
Organizer: Charles and Luo
Theme: This panel will examine developing world energy infrastructure. It seeks to see how growing nations will get their power in the future, especially as many countries see rapid population growth and subsequent energy demand growth. What are the best routes for meeting this need in a sustainable manner? Can distributed generation technologies carry the load? What other technologies and policies are needed? To what extent will developed nations contribute to the process?
Confirmed:
• Richard Hanson, Soluz Inc.
• Sam White, Promethean Power
• Professor David Dapice, Tufts (moderator)
4:15-4:45
Mindy Lubber, CERES
4:45-5:00
Closing remarks, Alex Clough, Conference Co-Chair
Co-sponsored by the Tufts Institute for Global Leadership and the Tufts Climate Solutions Coalition
We’ve been so busy over here at AIDG that unfortunately our blogging has fallen by the wayside. Good for our programs (yay!), bad for our readers (boo!). That said, I’ve have been twittering up a storm.
Here are some choice tweets from the past few weeks. Some abbreviations have been expanded for readability and to not incur the wrath of grammarians.
Haiti: From Natural Catastrophe to Economic Security by Paul Collier (Bottom Billion author ) [PDF] http://bit.ly/HPHI3. Today
Getting close to picking the Final 5 for our biogas biz plan compeition! Our extra push brought in some great apps from the community. Today
One of the dry composting public toilets we built with SOIL in the slum Shada is full. Yesterday we did some emptying at the compost site in Milot. 7:35 AM Mar 20th
Thinking about capital requirements for small business development in poor countries. It’s interesting to think about 10 Fortune 500 Companies that started w/little http://is.gd/lwSz . 8:10 PM Mar 19th
Pretty eye-opening and useful meeting with CHF International today. 8:00 PM Mar 18th
Bottom of the pyramid design is filled w/lots of vaporware. The design process tends 2B underfunded &/or paying clients can b hard 2 find. 1:53 PM Mar 18th
Checking out http://www.egiforhaiti.org/ and US based NGO that qualified Haitian university grads start small businesses. 12:42 PM Mar 16th
Had an excellent day talking to community groups about biogas and entrepreneurship. We’ve extended the business plan comp deadline to get more apps. 9:10 PM Mar 15th
4 ppl int in Last Mile internet, in Haiti we have NLOS wireless broadband provided by Access Haiti using Motorola’s Expedience. Wimax, baby. 12:38 PM Mar 14th
Woohoo. Jose Ordonez, our tech lead in Guatemala, & Meg Harper, a former intern, were both also accepted to MIT’s Int’l Dev Design Summit. 8:17 AM Mar 14th
3/3/86 Blast from the past: When was the last time that People magazine featured the wives of 3rd world dictators? http://tinyurl.com/aa9b73 . 12:01 AM Mar 13th
Congrats to Sam Redfield who got accepted to MIT’s Int’l Dev Design Summit taking place in Ghana this summer. 4:23 PM Mar 12th
Interested fundraisers will receive an information pack with all the details. You must have a phone and internet access to participate. This fundraising campaign begins April 15th, 2009 and ends December 31st 2009. Contact volunteers@aidg.org to request the information pack and please include a bit of information about yourself.
