The Twig Light: Ultra low-cost lighting in Ghana


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This session describes the development of a new, low cost, sustainable light source for poor villagers in developing countries called the Twig Light. The light makes use of a compact thermoelectric generator sandwiched and providing a thermal bridge between two pieces of ten-centimeter aluminum channel approximately fifteen centimeters in length. The lower section is cooled by sitting it in a small amount of water, while the upper section serves as a combustion chamber in which small pieces of wood or other combustible materials are burned. The subsequent temperature difference across the thermoelectric generator results in enough power to light a bank of LEDs sufficient to illuminate a small room. The technology was distributed in the rural Ghanaian village of Domeabra in the summer of 2009, and the performance will be evaluated during a return visit in 2010.

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The Twig Light: Ultra low-cost lighting in Ghana

  1. 1. Brad Rogers Mark Henderson Michael Pugliese College of Technology and Innovation Arizona State University at the Polytechnic Campus
  2. 2. GlobalResolve improves the world by building partnerships to create technological and economically sustainable solutions for villages in the developing world. The results are: 1. New products for the BoP to improve lives 2. New business ventures to build village economies 3. Life-changing educational experiences for students.
  3. 3. The GlobalResolve Method
  4. 4. •  Gelfuel production system •  Efficient stoves for Gelfuel •  Jatropha Curcas partnerships •  Low cost water filters •  Fire into Ice project •  Orange juice pasteurization system •  Developed at request of Chief
  5. 5. •  Classes provide “traditional” education and incubate and develop ideas •  Undergraduate students are engaged in design for the BoP market •  Courses Include: 1.  Traditional Engineering capstone sequence (6 credits) 2.  Three semester interdisciplinary capstone sequence (6-9 credits) 3.  Village Energy Systems
  6. 6. •  One semester, 3 credits •  Seniors, Graduate students •  75% Engineering students •  Format is Problem Based Learning •  Class requirements: –  Class project for BoP market •  Chosen by Instructor –  Individual project for BoP market •  Chosen by each student based on their interest and talents
  7. 7. •  Graduate Student (Michael Pugliese) decided to address the problem of clean, safe and affordable lighting •  Solution was to utilize a Thermoelectric Generator to power a bank of LEDs.
  8. 8. •  Upper and lower chambers are aluminum channel •  Lower chamber sits in pan of water •  Supported by NCIIA and manufactured in ASU labs
  9. 9. •  Successful products require field testing in a well understood environment •  Domeabra is a typical rural African village, and is serving as a Village Laboratory
  10. 10. •  Villagers preferred to use leftover coals from cooking fires to power the unit •  The increased surface temperatures from the hot coals led to burnout of the TEGs. –  This was not observed in the limited testing with twig combustion •  Initial student designed prototypes from the capstone suffered the same fate –  Thermal control is a key
  11. 11. •  Combustion based lighting is expensive and unpleasant, but is often all that is available. •  Competing “clean” technologies include PV coupled with rechargeable batteries and direct battery devices. –  Solar PV systems are typically more than $30. •  D Light claims a $10 product will be out soon •  Twig Light material costs are in the range of $10. –  Advantage of Twig Light – no need to wait for the Sun to recharge •  Attending the Lighting Africa conference in Kenya for more careful assessment
  12. 12. •  Engineering Capstone team developing next generation for field testing –  Power unit •  Thermal Management has been primary design constraint –  Application unit •  LED arrays •  Cell phone charging •  High frequency sound for mosquito control (?)
  13. 13. •  Capstone students are graduating soon •  New team of students applying for Edson entrepreneurial grant to develop business •  Product design efforts have been initiated
  14. 14. •  Several villages, with Domeabra being the largest •  About 30 square miles •  More than 10,000 people •  Typical income is less than $2 per day, usually less than $1 •  Most villager’s income is primarily obtained from small farms
  15. 15. •  Village appraisal meetings provide a forum to establish trust. •  Villagers use products under realistic conditions and report on performance.
  16. 16. •  Nana Frempong Afaokwa: –  Graduate of the Massachusetts Institute of Technology in Mechanical Engineering –  Started and operated a successful manufacturing business in New York for 25 years –  Returned to Africa as Paramount Chief of the Domeabra Traditional Area in the Asante region of Ghana
  17. 17. •  Our partners in Domeabra and at KNUST provide continuous feedback to us. •  Product improvements are made in Arizona as needed, and further tested in Domeabra. –  Principles of Design for Extreme Affordability are always followed –  All products will be manufactured in Africa to the extent possible •  When the products are shown to be reliable and useful in the African environment, supply chains are identified and the product is offered in the greater market
  18. 18. •  GlobalResolve is having an impact •  More than 100 students have been involved in GlobalResolve projects •  18 ASU students have worked on the ground in Africa on GlobalResolve projects •  We are just beginning!
  19. 19. •  Water capture in Gamoa-Dago •  Twig Light optimization, marketing, supply chain (KITE) •  Cell Phone charging attachment for twig light •  Gelfuel demonstration at Kumasi elementary school •  Fire into Ice project •  Jatropha Curcas as a Village Energy Resource –  Extraction –  Diesel based multifunction platforms –  Cooking –  Industrial fuel for Suame Magazine •  Developments in Uganda •  Certificate Program at ASU •  Global Innovation capstone at ASU
  20. 20. •  Seniors in Engineering at the Polytechnic Campus –  Students given opportunity to work on BoP problem –  Gelfuel production facility –  Improved Gelfuel stoves –  Development of Twig Light
  21. 21. •  Interdisciplinary, International, Intercultural approach to reduction of extreme poverty through social entrepreneurship •  Travel, learn and identify problems. •  Form global teams to address problems –  Students –  University Faculty –  Villagers and Chiefs –  NGOs –  Government organizations
  22. 22. •  WeVillages ask the questions: •  What are the problems? •  Who can solve the problem? •  Who can implement the solution? KITE •  What funding sources are available? •  We create alliances for expertise, connections and funding •  Universities, Companies, Foundations •  We involve partners on the ground •  Villagers, Companies, NGOs, Local university students