The original author of this article is Dr. Ashok Kundapur. Find more of Dr. Kundapur's work on his website: http://www.solcooker.net/Cindex.htm. |
Template:Compendium TOC
Introduction
The main purpose of this compilation is to present all possible major designs and their variations so as to prevent the solar cooker designer from wasting time creating a design which has already been under the sun.
- For more details on the Compendium, see Compendium Introduction.
Concentrator Types
Concentrator cookers offer several advantages, including a mode of cooking very similar to day to day cooking. They come in many designs, classed according to whether they concentrate light from above or from below.
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|Cylindro-parabolic cookers
This design was common in water heating, but was later tried out for cooking as well, so as to cook food in more vessels.
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|Plane mirrors
Plane mirrors, especially small pieces, yield very well to form various shapes, be it parabola, or cylindrical configurations.
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Cookers which concentrate light from above
In this type of solar cooker, the light is concentrated from above. Though this approach is not the most efficient for cooking, there are several old designs and many new designs that have used this method. One of the most interesting and popular design in this category is the CooKit created by Professor Roger Bernard of France.
Lenses These cookers use one or more lenses (often a fresnel lens) to concentrate light instead of reflectors. | |
Panel cookers Simple, cheap, effective - most panel cookers are just a packet of interconnected reflectors. They unfold into a small bracket of reflectors around a central space where a cooking vessel sits in a transparent container of a heat resistant plastic. The simple cooker works well and is one of the most popular solar cookers on the planet. | |
Funnel cookers The funnel cooker has several advantages: it is simple to construct, and also store, and there is hardly any wastage of sheet. Supporting the funnel may pose problem in the beginning but you can easily solve the problem with, for example, a small hole in the ground to hold the base of the funnel. |
- For more details on this topic, see Concentrators from above.
Box-types
Box cookers are another group of old but popular solar cookers. The very first box cooker design was probably that of Nicholas de Saussure (1740-1799). It was simply an insulated box with glazing; this design forms the basis of all present designs of box-type cookers including Warenham’s (1995) ‘Sunstove’.
The box cookers presented here are classified on the basis of the presence or absence of reflectors, i.e., those without or with mirrors boosters.
See also Principles of Solar Box Cooker Design.
Box cookers without external reflectors One of the first cooker types designed on this planet. They are still on the scene. | |
Box cookers with external reflectors The Box cooker work well, but to improve the performance reflector boosters are added. Further classification of this type of cooker is based on number of reflectors. |
- For more details on this topic, see Box cookers.
Selecting the best design
Evaluation of cookers
Suggested criteria for evaluation:
Ease of use
This has to be the primary criterion. No matter how good a design is in other respects, if it is difficult to use it will not succeed.
Cooking capacity
Capacity can be measured by the volume of food that can be cooked at one time, or by the mass of that food.
Cooking power
Power measures the amount of heat the cooker can produce in a specified time. Power may be measured in watts, or in Btu per second, or kilogram-calories per second. Maximum power depends on the angle of the sun, the ambient temperature, wind speed, air clarity and other factors that should be specified in describing the cooking power. This is the criterion that allows us to identify regions of the world where a particular design is appropriate.
Maximum temperature achieved
In addition to cooking power, the maximum temperature achievable should be defined. This also will depend on angle of the sun, ambient air temperature, wind speed and air clarity. Since different foods require different cooking temperatures, it is important to identify this criterion as well as cooking power.
Cost of materials
Since it is often the case that solar cookers will be used by the poor, cost is an extremely important criterion. Even minor differences in cost can make a significant difference in comparisons of designs.
Availability of materials
Even very low cost materials, such as the shiny wrapping paper that is discarded in developed countries, may be difficult to obtain in developing countries. Indigenous materials in a given location may be important benefits to the overall design.
Ease of construction
It is desirable that solar cookers be assembled by local unskilled labor in order to save cost and reduce training requirements.
Transportability
Cookers should be able to fold in some way to make them more compact for storage and shipping. They should be light in weight.
Durability
Cookers should last a long time without need for repair. Reflective surfaces should not require frequent cleaning.
Safety
Cooker temperature should be moderate, never burn food or cause smoke or fire, pots should have cool handles and be stable against spills, etc. Protection of children should be considered in the overall design.
Open source
Recommendations
- See Recommendations
Conclusions
Solar cookers are here to stay, or to put it in the other way, if we have to preserve our planet then each and every one of us has to use one or the other type of solar gadget, be it a cooker, a solar water heater, or solar photovoltaic panel.
References
- See References
Other links
- See Other links