Research » Fluids and Heat Transfer
Title
The µPower stove generator
Project coordinator(s)
Dr. Tony Robinson
Email: arobins@tcd.ie
Tel: +353 1 896 3919
Post Doctoral Fellow
Dr. Séamus O'Shaughnessy
Post Graduate
Mr. Maurice Deasy
Project Sponsors
Irish Aid, IRCSET, Intel, Electric Aid (ESB), Cara Malawi, Dr. Anthony Robinson
Description
This technology generates electricity from the heat of efficient biomass cook stoves currently being deployed on an unprecedented scale in the developing world. Approximately 2.5 billion people living in the developing world burn biomass as a primary energy source. This number is expected to grow to 5 billion by 2050. Over half of those who burn biomass lack access to grid electricity. An astonishing number of people at the base of the pyramid have no access to night time lighting, meaning complete darkness once the last cooking fire goes out. Those who do have the luxury of lighting predominantly use kerosene. The negative cost, health, safety, security and environmental consequences are too numerous to list.
Operation of Generator
The µPower Stove Generator utilizes a thermoelectric generator (TEG), a solid state device which converts heat directly into electricity by means of the thermoelectric effect. A thermoelectric module generates electricity when heat flows across the module from a heat source and is dissipated to a heat sink. In application, the heat source is the fire in the cooking stove and the heat is dissipated to the surroundings using a commercially available heat sink and a specialized fan system.
The heat is extracted from the stove using collecting rods which also act as a grate. A metal shim is also used to protect wires from the flames. Both the grate and the shim are additions to the stove which ensure that there is no adverse effect on cooking time and to potentially improve the performance of the stove.
Assembled generator with heat collection rods, heat sink, fan and circuit box
The electricity is then used to power a low power fan with the excess power being stored in a rechargeable battery. The fan uses a maximum power of 0.4 Watts while the generator is capable of generating a maximum of around 6 Watts. The power in the battery can then be used from a 5 volt USB connector to charge mobile phones or lights and even radios.
Circuit bow which contains charging circuit, battery and USB output
Tests carried out in Trinity College Dublin showed that over three one hour cooking periods, the µPower Stove Generator was capable of generating and storing 8Whrs of electricity. This is sufficient electrical energy to charge a phone and still have enough to charge a LED lantern.
Malawi Field Trials
The generator was developed for integration into an improved cook stove, the Chitetezo Mbuala. The Chitietezo Mbaula is promoted by Irish Aid and Concern Universal and is produced predominately by women’s groups in rural areas. To date almost 17000 cooking stoves have been disseminated by Concern Universal.
Chitetezo Mbaula stoves ready for integration of Thermoelectric Generator. Courtesy of Deirdre Mulrooney
Balaka Field Trial
The Field trials began in Balaka, Malawi in December 2011 and were carried out in collaboration with Concern Universal. Initially five generators stoves, with data logging equipment, were deployed to homes villages surrounding Balaka along with five control stoves without generators though with logging equipment.
Completed Generator stove being tested in Concern Universal Courtesy of Deirdre Mulrooney
Children observe the distribution of generators stove in Mponda Village , Balaka
Distribution of control stoves in Dulani village, Balaka
We are very grateful to all those who participated and made the field trial possible, especially the Concern Universal staff. The data-loggers were retrieved after nearly three months in the field to evaluate the performance of the generators while the generators remained with the participants to allow them continue to charge their mobile phones and lights from power generated while cooking with their Chitetezo Mbaula cook stove.
A generator stove being used for cooking and charging a phone at the time of collecting of the data
The stoves proved successful and very well liked by the participant families. Some of the stoves were used for an average of seven to eight hours a day, far exceeding expectations of three one hour cooking periods. On collection of the data all the participants spoke of the benefits of charging the LED lanterns and mobile phones from their Chitetezo Mbaula. We even observed a stove that had been rigged to power a radio, showing the inventiveness and resourcefulness of the local people.
A generator stove being used to power a radio
Ntcheu Field Trial
With the successful first trial of the generators, a second field trial began in July 2012 in Ntcheu, Malawi. This trial involved ten generators deployed in two separate villages using data-logging equipment to monitor the usage of the generators. Several improvements were made to the generator including a lower cost heat sink and more efficient charging circuitry.
Integration of generator and data-logging and testing of stoves prior to deployment
It is believed that this field trial will continue to give technical and behavioural information on the usage of the stoves and the performance of the generators. This information will then be used to make further refinements to the design of the generators leading to the first commercially viable prototype.
Generator stoves being distributed in Ntcheu, Malawi
This project has been possible due to support of the funding bodies as well as with the assistance of Concern Universal and its wonderful staff whom have made it possible to bring this research to the field.
For further reading follow the links to the videos, paper and articles and please feel free to contact us about this project.
Related Links
Journal Paper
S.M. O’Shaughnessy, M. Deasy, C. Kinsella, V. Doyle, A.J. Robinson, (2012) “Small Scale Electricity Generation from a Portable Biomass Cookstove: Prototype Design and Preliminary Results,” Applied Energy (in press). http://dx.doi.org/10.1016/j.apenergy.2012.07.032
YouTube Videos
Off the Grid in Malawi:
http://www.youtube.com/watch?feature=player_embedded&v=3OU2ruj-fKQTCD Malawi Stove Project Video
http://www.youtube.com/watch?feature=player_embedded&v=Uot0g9Xwys4
Articles
Deirdre Mulrooney in Village Magazine
http://deirdremulrooney.blogspot.ie/2012/03/sustainability-in-colourful-malawi-in.html