Solar cookers
Page data
Keywords solar, cookers, Homepage, manufacturing
SDG Sustainable Development Goals SDG02 Zero hunger
SDG07 Affordable and clean energy
Authors David Williams
Tiago Galletti
Joshua M. Pearce
Chris Watkins
Pedro Kracht
Tom Sponheim
Published 2006
License CC-BY-SA-3.0
Derivatives Kubika nesimba rezuva
Language English (en)
Impact Number of views to this page. Views by admins and bots are not counted. Multiple views during the same session are counted as one. 15,681

A solar cooker converts sunlight to heat energy that is retained for cooking. Sunlight is the "fuel." The requirements for solar cooking are very simple. You must be able to place the solar cooker in a location that gets sun for several hours and be protected from strong wind. Solar cookers, obviously do not work at night or on very cloudy days. The sunlight is absorbed on dark surfaces that heat up. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture. To retain the heat created when the black pot absorbs the suns rays some form of transparent cover is needed. This can be as simple as a clear plastic bag or as complicated as evacuated multiple layers of glass. One method to speed the cooking process is to use reflectors to increase the concentration of sunlight on your collector.

The overarching authority on solar cooking is Solar Cookers International (SCI). They spread solar cooking awareness and skills worldwide, particularly in areas with plentiful sunshine and diminishing sources of cooking fuel. SCI has enabled 30,000 families in Africa to cook with the sun's energy, freeing women and children from the burdens of gathering wood and carrying it for miles. SCI also maintains an excellent wiki of solar cooker designs.

Projects on Appropedia[edit | edit source]

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Designs[edit | edit source]

Solar cookers are solar concentrators where precision and efficiency has been sacrificed for ease of construction and use of readily available materials. Inexact geometries that still allow for water boiling or bread baking temperatures are used.

Solar cookers are usually of the solar funnel, Parabolic (e.g. Focus-balanced paraboloid) or compound parabolic type. See also Using Two Parabolic Troughs to Simulate a Paraboloid.

Some calculations relevant to the design of solar cookers with paraboloidal reflectors can be found on the Sun related calculations page.

Solar funnel[edit | edit source]

Funnel.png
A solar funnel is the basis for many solar cooking designs. In it, light is funneled by flat reflectors to a pot or other surface to be heated which is located on the other end of the funnel. This differs from designs where the pot sits between the sun and the reflectors, as in most parabolic cookers. A solar funnel is the flat version of the more idealized Compound Parabolic Concentrator.

Parabolic solar cooker[edit | edit source]

Sun cook.jpg

A parabolic solar cooker is essentially a solar thermal collector used to cook food or pasteurize water. Parabolic designs have been used for centuries. The idea to concentrate light using curved mirrors was developed by the Greeks, Aztecs, Incas, Romans and Chinese. The Incas used bronze and gold for their mirrors and they built structures that were several stories high. This technology seems to have appeared around the same time for each of the civilizations.

There are many designs and models for parabolic solar cookers. Some are made with locally gathered scrap materials while others are manufactured using highly machined, durable but more expensive materials. Here are links to and photos of a number of parabolic solar cooker designs.

Compound parabolic concentrators[edit | edit source]

Compound parabolic concentrators (CPCs) are a class of concentrators that consist of rotated parabolic sections which have a concentration factor for planar receivers which is the thermodynamic limit: 1/sin(θa) where θa­ is one-half of the angle within which the reflectors direct all the light incident onto the aperture down to the receiver. Compound parabolic concentrators (CPCs) can be additions to solar water stills, solar water pasturizers, and solar cookers. CPCs can increase the output of these devices along with their efficiency by concentrating the sunlight to make the device more effective.

Recently research has shown that by incorporating compound parabolic concentrators (CPCs) for augmenting the light collection of a solar still [1] and a solar water pasteurizer,[2] the efficiency and throughput can be improved.

Integrated cooking[edit | edit source]

Integrated cooking combines the use of:

  1. An appropriate solar cooker model whenever the sun is shining;
  2. A retained heat cooker (hay basket or fireless cooker) to extend cooking time and keep food hot for 3-4 hours after cooking; and
  3. An improved cookstove (i.e. efficient cook stove) for use when there is not sufficient sunshine.

Solar cooking and health[edit | edit source]

Figure 2: Box oven, Bolivia. Photo; David Whitfield.

The good news is that it is possible to breathe fresh air at the same time as cooking – using a solar cooker. Solar cooking produces no smoke at all.

In the past, the main reason for people adopting solar cooking was to reduce the environmental degradation caused by using too much fuel wood. More recently, respiratory diseases caused by toxic smoke from cooking fires have been recognized as a major health problem. They kill 1.5 million women and children each year, according to the World Health Organization (WHO). Solar cookers address these major threats to health as well.

Solar cooking technology has been around for decades, but has been poorly understood and has not been widely disseminated. Here are some ideas on what solar cooking is about, and its capabilities – as well as its limitations.

Solar cooking and violence[edit | edit source]

Solar cooking has an unexpected relationship - good and bad - with violence.

  • Anecdotes exist that solar cookers are not promoted by some NGOs in Africa due to domestic violence. When the weather has not been suitable for cooking, and the husband returns home to find no meal ready, he may become violent towards his wife. (This raises other issues, but one immediate issue is not to aggravate the victim's situation by having an unreliable cooker.)[verification needed] This failure of the meal to cook may have a technological solution: integrated cooking (see Wikia:Solarcooking:Integrated cooking method).
  • In Darfur, solar cooking has meant women have not had to leave safe areas searching for firewood - thus these cookers are keeping them out of harms way.

The points above come from email conversations. I hope to find get people with experience in these things to contribute to Appropedia. --Chriswaterguy · talk 00:20, 31 October 2007 (PDT)

Solar Cookers World Network[edit | edit source]

The Solar Cookers World Network is an alliance of more than 500 non-governmental organizations (NGOs), manufacturers, and individuals actively promoting solar cooking in more than 100 countries. This wiki-based site allows Network participants to share information and collaborate on projects and research. Solar cooking is an important part of Integrated Cooking, which also includes the use of fuel-efficient woodstoves and heat-retention cookers.

See also[edit | edit source]

External links[edit | edit source]

References[edit | edit source]

  1. Joshua M. Pearce and David C. Denkenberger, "Numerical Simulation of the Direct Application of Compound Parabolic Concentrators to a Single Effect Basin Solar Still", Proceedings of the 2006 International Conference of Solar Cooking and Food Processing, p. 118, 2006. http://images.wikia.com/solarcooking/images/c/cd/Granada06_Joshua_pearce.pdf open access
  2. David C. Denkenberger and Joshua M. Pearce, "Compound Parabolic Concentrators for Solar Water Heat Pasteurization: Numerical Simulation", Proceedings of the 2006 International Conference of Solar Cooking and Food Processing, p. 108, 2006. Available: http://images.wikia.com/solarcooking/images/2/2e/Granada06_david_denkenberger.pdf