A low-cost solar cooker for the developing world

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

Abstract

The aim of this project is to improve on existing research carried out by Oxford and user-test in the field a prototype solar cooker. This will develop the technology to improve the usability of the final prototype. The proposed work will be carried out in collaboration with an industry partner, Dytecna Ltd.

An estimated 1.6 million people in the developing world die each year from smoke inhalation due to cooking indoors using biomass and fossil fuels (WHO). An effective low-cost solar cooker would not only save lives but would enhance the quality of the lives of women and children by removing the necessity of long treks to collect ever decreasing amounts of brushwood. This would allow more time for children to study or play and for women to do other important activities. They would also reduce the risk of accidental fires, which can be a hazard in dry climates. Solar cookers can be used in large parts of Africa, in parts of India and China, and elsewhere in the world, so the potential humanitarian benefit is significant.

The UN has recently laid down a challenge to industry and academia (http://www.solarcookers.org/index.html) to develop a better solar cooker than is currently available: in particular, the widely used foil-lined cardboard panel cooker, which heats a cooking pot inside a plastic bag, is not very durable and is not felt by the large relief organizations to be a viable technology.

Research funded by the Leverhulme Trust on a low-cost solar concentrator using simple surfaces has shown that two single curvature surfaces can focus sunlight to a point and in a way well-suited for a solar cooker: the Sun's energy is directed to the underside of the cooking platform, which is located away from the ground and where the user can be shielded from the direct sun. The first reflective surface is conical and the second parabolic and the combination can produce ~350 W at a point focus from a system that has a footprint of only 0.8 m2.

The single curvature surfaces in the concentrator mean that the reflective surfaces can be formed from flat reflective sheets, so tough anodized aluminium sheets could be used. This would not only reduce costs and enable the concentrator to be flat-packed - an essential requirement for disaster relief operations, but also to be very durable. A cooking temperature of about 200 0C is estimated, avoiding the need for any special heat enhancing and easily damaged consumable cooking aids, such as a delicate plastic bag. No other system will concentrate so much naturally available renewable energy into such a compact and usable solution. The design has been called the 'Albedo Solar Cooker'.

Field trials in the UK, Europe and Africa will be carried to user-test the performance of the design based on a pre-prototype, which only had limited functionality, with a successful evaluation allowing the project to proceed to the next commercial phase. The results of the field trials will be used to improve the production standard design. The potential will be looked into for using non-imaging concentrators to increase the concentration and hence temperature of the cooker, for adding thermal storage to enable evening cooking and possibly thermoelectric generation for mobile phones.

Publications

10 25 50
 
Description We have trialled the first prototype solar cooker in Italy in August 2014. The cooker performed well. We are making some small changes to simplify the construction of the cooker before sending several cookers to Africa for trials.

The trials in Tanzania were useful, and the volunteers showed enthusiasm for use of the cooker and some meals were cooked. Since direct insoaltion is required, the performance was compromised by haze in the coastal region and dust in the inland areas.

There is now a follow-on project with GCRF funding and a solar concentrator with a 25 m^2 aperture is being built in India. This is intended with water treatment and other higher temperature applications
Exploitation Route The trials are essential for establishing that our design fulfils the needs of the local communities in Africa. A native Tanzania university lecturer thought that the design was well suited to his communities' cooking and will be helping with some of the trials.
Sectors Agriculture, Food and Drink,Healthcare

 
Description Oxford Alumni event at Kellogg College 11 June 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Several Oxford alumni interested in solar cooker and its role in improving health and welfare in developing world

Useful discussion with aid agency worker about solar cooking issues
Year(s) Of Engagement Activity 2014
URL http://www.energy.ox.ac.uk/wordpress/wp-content/uploads/2013/09/CaseStudies_5.pdf