Solar Cooking
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[[File:Solar Cooking in Africa - A Remarkable Technology Transfer|450px|none]]
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Below you will find an '''introduction to solar cooking'''. The Solar Cooking Wiki also provides an individual page for [[:Category:Countries|{{CountryCount}} different countries]] where you will find news, NGOs, manufacturers, and individuals working on solar cooking projects in that country. Links to possible funders are also available:
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Depending on [[Where is solar cooking possible?|where you live]] and how you cook, solar cooking can save you time, effort, and fuel. It is also an environmentally friendly and fun way to prepare your meals. All foods can be cooked in some type of solar cooker.
   
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Cooking with a [[solar box cooker]] or [[solar panel cooker]] is similar to using a [https://en.wikipedia.org/wiki/Slow_cooker slow cooker (crock-pot)]. Typically, [[Guidelines and cooking tips|cooking times]] for these types of cookers are twice that of conventional cooking methods, however, slower cooking also has its advantages. These cookers provide a moderate, even heat, are only reoriented once towards the sun over several hours of cooking, and the food does not have to be stirred during cooking. This frees the cook up to do other useful tasks while the food cooks independently.
   
  +
[[Parabolic solar cooker]]s offer another approach to solar cooking by being able to reach higher temperatures and perform more like a traditional stovetop. As such, they require more attention while cooking to avoid burning the food and they need to be turned periodically to follow the sun, depending on cooking time.
[[File:KoZon_Iridimi_May_2007_1.jpg|thumb|Tens of thousands of solar cookers are in use in [[refugee camps]] in Chad.]][[File:Sharon_cousins1.jpg|thumb|Tens of thousands of solar cookers are also in use in developed countries.]]
 
Below is a collection of articles about solar cooking basics. If you are interested in trying solar cooking for the first time yourself, you may be wondering whether it is best to build your own solar cooker, or to buy a finished solar cooker commercially. Take a look at [[How solar cookers work|how solar cookers work]] to help understand the principles of solar cooking. Building your own solar cooker can be fairly easy and inexpensive way to go. Various types of solar cookers that are available to build are listed at [[:Category:Solar cooker plans|build a solar cooker]]. You will find information there comparing the [http://solarcooking.wikia.com/wiki/Category:Solar_cooker_plans#Selected_designs advantages and disadvantages] of each style of cooker. There are also many solar cookers available commercially. Commercial cookers are typically well made, and waterproof. The location of the retailer will be important to consider to avoid high shipping costs. See possibilities at [[:Category:Manufacturers and vendors|buy a solar cooker]].
 
   
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For areas in the world experiencing [[deforestation]] and limited access to [[Water pasteurization|clean water]], solar cooking is a valuable [[Integrated Cooking Method|part of the solution]], by providing a safe, [[Household air pollution|smoke-free]] alternative method of cooking and pasteurizing water.
Once you have decided on a cooker, you will need to find appropriate [[Solar cooking pots|cookware]]. Thin-walled dark enameled metal cook pots work well. They are good at heating up quickly. Cast iron pots also work, and are typically preheated in the solar cooker before cooking. The advantage of the heavier pots is that they will help maintain an even cooking temperature if the sun is occasionally blocked by clouds, but most solar cooks seem to use the enamel pots. Because dark cooking pots work the best in solar cookers, it is important to remember to use a [[Paint|nontoxic paint]] for the exterior cook pot surface if you choose to darken your own pots.
 
   
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==Buy or build a solar cooker?==
Consider the type of foods you will be preparing in your cooker. [[Solar panel cookers]] and [[solar box cookers]] are simple to use, and are best at baking and slow cooking, similar to crockpot cooking. [[parabolic solar cooker|Parabolic solar cookers]] will require frequent reorientation to the sun, but have the ability to fry foods and cook food on a griddle. [[Cooking guidelines]] will explain the best way to prepare specific food types. There are also many [[Recipes|recipes]] of proven approaches to great dishes, but basically, most any recipe will work with the right solar cooker, by simply allowing for more cooking time. Most solar cooks will advise to not add much extra liquid when cooking, as you might do with traditional stovetop cooking. The natural juices of the food are retained when solar cooking.
 
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[[Image:CooKit.jpg|right|thumb|275px|The [[CooKit]] is an example of a simple [[solar panel cooker]], probably best suited to locations close to the equator]]
 
  +
If you are interested in trying solar cooking for the first time, you may be wondering whether you should [[:Category:Solar cooker plans|build your own solar cooker]], or to [[:Category:Manufacturers and vendors|buy one from a manufacturer]]. There are advantages to both options:
==Introductory articles==
 
  +
#Building your own solar cooker can be a fun and cost-effective way to get started.
*[[Why solar cooking is important]]
 
  +
#A wide variety of solar cookers are available for purchase, and you will often receive a higher-quality cooker than one you might build yourself.
  +
  +
If you would like to build a cooker, visit the [[:Category:Solar cooker plans|build a solar cooker]] page to choose a design that's right for you. You will find information there comparing the characteristics of each style of cooker.
  +
  +
If you would like to purchase a cooker, check out the list of manufacturers and vendors on the [[:Category:Manufacturers and vendors|buy a solar cooker]] page. Commercial cookers are typically durable and efficient, and offer an easy way for new users to experience solar cooking. As cookers are manufactured globally, consider potential shipping costs when selecting a design.
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==How do solar cookers work?==
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Solar cookers work on this basic principle: Sunlight is converted to heat energy, that is retained for cooking.
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Many [[solar panel cookers]] and [[solar box cooker]]s are capable of reaching {{Degree|150}}, or higher. The captured solar radiation passes through a greenhouse enclosure enclosing a dark colored cook pot. As it hits the dark surface, the solar radiation is converted to heat, which is contained within the [[Glazing|glazing]] enclosure, and cooking temperatures are achieved. The same principle is often experienced by drivers returning to a hot car that has been parked in the sun. The efficiency of these cookers is typically determined by the amount of reflector area available of the solar cooker to gather sunlight, and the ability of the greenhouse enclosure to receive the available light and help insulate the hot cook pot. Double Pyrex bowls have been shown to work well as greenhouse enclosures for solar panel cookers. See: [[Glazing]] for additional enclosure ideas.
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<table style="width:100%">
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<td>[[File:Intro-sun.gif|thumb]]</td>
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<td>'''{{ColoredText|Fuel: Sunlight|green}}'''<br/>
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Sunlight is the fuel. A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days.<br />&nbsp;<br /></td>
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</tr>
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<tr><td colspan="2">'''{{ColoredText|Convert sunlight to heat energy|green}}'''<br />
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Dark surfaces get very hot in sunlight, whereas light surfaces don't. Cooking is typically best done with dark, shallow, thin metal pots with dark lids to hold in heat and moisture. The thin metal cook pots heat up quickly, but thicker pots will retain heat longer and should be preheated before adding the food.
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[[File:Intro-pot_color.gif|center]]
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</td></tr>
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<tr><td colspan="2">'''{{ColoredText|Retain heat|green}}'''<br />
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A transparent heat trap around the dark pot lets in sunlight, but keeps in the heat. This is a clear, heat-resistant plastic bag or large inverted glass bowl (panel cookers) or an insulated box with a glass or plastic window (box cookers).
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[[File:Intro-glazing.gif|center]]
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</td></tr>
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<tr><td colspan="2">'''{{ColoredText|Capture extra sunlight|green}}'''<br />
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One or more shiny surfaces reflect extra sunlight onto the pot, increasing its cooking potential.
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[[File:Intro-reflectors.gif|center]]
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</td></tr>
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</table>
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*[[Parabolic solar cooker]]s use a bowl shaped reflector to focus the light directly onto the cook pot, usually from below. Typically they do not require a greenhouse enclosure to retain the heat. They reach much higher temperatures than the other styles of solar cookers, usually above {{Degree|200}}, and also have the ability to fry and broil foods.
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::[[File:SolSource_Solar_Stove_with_Cookware.gif|thumb|left|250px|[[SolSource]] is an example of a [[parabolic solar cooker]] shown with cookware. The light is focused at the bottom of the cook pot.]]
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[[File:Industrial_scale_cooking,_Solare_Brucke,_6-10-15.png|thumb|300px|[[Institutional solar cooking]] can employ many large [[parabolic solar cooker|parabolic]] reflectors to generate steam, and cook for thousands of people daily. A number of these systems are in use in [[India]]. This example, was built with technology from [[Solare Brücke]].]]
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{{clr}}
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{{Main|How solar cookers work}}
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==Solar cooker types==
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The three most common types of solar thermal cookers are [[box cookers]], [[panel cookers]], and [[parabolic cooker]]s. Hundreds — if not thousands — of variations on these basic types exist. [[Evacuated tube solar cooker designs|Evacuated tube cookers]] and [[Trough solar cooker designs|trough cookers]] are two lesser known styles of cooker design. The two approaches are often combined, as the geometry of each is suited to the other. Additionally, several [[Institutional solar cooking|large scale]] solar cooking systems have been developed to meet the needs of cooking for lerge numbers of people.
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===Box cookers===
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[[File:All American Sun Oven.jpg|thumb|200px|[[All American Sun Oven]] [[Solar box cooker]]]]
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{{BoxCookerDescription}}
 
{{Main|Solar box cooker designs}}
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===Panel cookers===
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[[File:CooKit_photo_Make.jpg|thumb|200px|[[CooKit]] [[panel cooker]]]]
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Panel cookers incorporate elements of box and parabolic cookers. They often have a large reflector area and the cook pot has some form of clear enclosure to retain heat. Panel cookers are capable of cooking at approximately {{Degree|170}}. They are the easiest style to [[:Category:Solar_panel_cooker_plans|make]] and relatively inexpensive to buy.
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{{Main|Solar panel cooker designs}}
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===Parabolic cookers===
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[[Image:AlSol 1.4.jpg|thumb|300px|The [[AlSol 1.4]] [[parabolic cooker]] demonstrates how the cook pot is supported to receive the focused light from below from the reflector.]] Parabolic solar cookers use a bowl shaped reflector to focus the light directly onto the cook pot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. The parabolic name refers to the shape of the curve of the reflector cross-section.
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They require more frequent reorientation to the sun, possibly every fifteen minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching temperatures over {{Degree|200}}. They also have the ability to fry and broil foods. Generally parabolic solar cookers will need to be attended to more than box or panel cookers to avoid possibly burning the food at the bottom of the cook pot. They are especially useful for large-scale [[institutional solar cooking]] systems.
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{{Main|Parabolic solar cooker designs}}
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===Trough cookers===
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[[File:Early GoSun cooker, 2-29-16.png|thumb|250px|The [[GoSun]] is an example of a [[Trough solar cooker designs|trough solar cooker]] that also uses an [[Evacuated tube solar cooker designs|evacuated tube]] cooking chamber.]]
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For capturing sunlight, trough solar cookers use a reflector with a curved parabolic cross-section, that continues as a straight trough in the other direction. Instead of focusing the light at one spot like a typical bowl-shaped [[Parabolic|parabolic solar cooker]], the light is reflected along what is known as a focal line. These reflectors are easier to fabricate than a parabolic dish, but require a long fairly narrow cooking tray, which is why they work well with [[Evacuated tube solar cooker designs|evacuated tube]] enclosures.
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{{Main|Trough solar cooker designs}}
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===Evacuated tube cookers===
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[[File:SLiCK SM70 photo, 8-19-15.png|thumb|250px|The [[SLiCK SM70]] is an example of an [[Evacuated tube solar cooker designs|evacuated tube]] style solar cooker.]]
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Evacuated tube literally means that the cooking chamber is constructed of two layers of blown glass in the shape of a sealed tube, where the air has been removed between the layers.
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Heat loss often happens by conduction through a medium or by and convection through the air. With no air between the layers of glass, the chamber is nicely insulated, and well suited for retaining cooking heat. The chamber is so effective at insulating it often does not require a large reflector to capture sunlight. A slender cooking tray can be inserted from one end. The opposite end is either sealed with a stopper, or has been sealed during the manufacturing process. Improvements in glass technology is allowing for larger diameter tubes to be fabricated, which will allow larger cooking trays to be inserted inside.
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{{Main|Evacuated tube solar cooker designs}}
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===Other types===
 
*[[Fresnel solar cooker designs]]
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*[[Solar wall oven designs]]
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*[[In-the-ground solar cooker designs]]
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*[[Photovoltaic cooker designs]]
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*[[Hybrid solar cooker designs]]
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*[[Institutional solar cooker designs]]
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==Beyond performance ratings==
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Various methods of [[Testing|testing]] are available to evaluate the performance of solar cookers. [[Solar Cookers International]] responded to requests from cooks, manufacturers, and organizations to create an objective, scientific process to evaluate the cooking potential of different cookers, and developed the [[Performance Evaluation Process]] (PEP). A number of solar cookers have been tested with this method, and can be seen at [[PEP tested solar cookers]].
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Beyond cooking performance, other factors should be considered when designing, [[:Category:Manufacturers and vendors|purchasing]], or [[:Category:Solar cooker plans|building]] a solar cooker.
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*'''Cost:''' The cost of all supplies needed for the solar cooker - including estimated replacement parts needed within five years, compared to the cost of alternative cooking methods and the fuel used in them over five years. Also to consider: [[Environmental benefits of solar cooking]]
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*'''Convenience:''' The cooker either needs little or no attention during cooking or, the instructions address how often adjustments are needed during a cooking period (for example with [[:Category:Parabolic solar cooker designs|parabolic cookers]], frequent turning to track the sun or stirring to prevent burning). If movable, is the cooker easy to move and easy to store? What is required to check on the cooking food, and remove it from the cooker when done?
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*'''Safety:''' The cooker should be incapable of starting an accidental fire inside or outside the cooker. A warning included that the reflectors remain at ambient temperature, but the cook pots become quite hot. In the case of [[:Category:Parabolic solar cooker designs|concentrator cookers]], warn of risk for accidentally damaging eyes or burning hands at the focal point. Modern designs usually incorporate a deep parabolic reflector to avoid these types of accidents. See also: [[Health benefits of solar cooking]]
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*'''Cooking capacity:''' Can the cooker prepare a meal for at least a small family, and/or specify size of family it is intended to cook for? In some cultures it may be important for the cooker accommodate a variety of covered pots and pans to prepare the local cuisine.
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*'''Durability, maintenance:''' Repairs should be infrequent, and/or possible to do without special equipment, with replacement parts readily available or easily made DIY. Instructions included for ordinary maintenance or repair as needed (such as wiping off dust from windows and reflective surfaces). Information should indicate expected durability under various weather conditions, and/or guides for protecting it when weather may damage it.
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*'''Wind stability:''' The cooker should be reasonably stable in wind to avoid spilling food, or should include instructions to easily make it so (for example; tie-downs or placing rocks in specified places).
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*'''Instructions:''' Clear guides for estimated length of cooking time and variables that influence cooking time (food quantity, wind, etc.) See: [[Guidelines and cooking tips]]
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==Using your solar cooker==
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[[File:CooKit_photo_Make.jpg|thumb|300px|The [[CooKit]] solar panel cooker with a dark pot enclosed in a plastic bag]]
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The golden rule for solar cooking is get your food on early, and do not worry about overcooking. Most people starting to solar cook will be using a [[solar panel cooker]] or [[solar box cooker]]. These cookers are oriented to the sun and typically don't need to be turned to follow the sun during a 2-4 hour cooking period, though cooking time can be shortened if the cooker is turned.
  +
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Once you have decided on a cooker, you will need to find appropriate [[Solar cooking pots|cookware]]. Thin-walled dark enameled metal cook pots work well. They are good at heating up quickly. Glass jars can also be used, either clear or preferably [[Paint|painted]] on the outside. Please note that all cooking vessels need to have a lid, but not be completely sealed to avoid steam pressure build-up. Pots that reflect light, such as silver aluminum pots, will not work as well. Paint these first.
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When using a solar panel cooker the pot is normally placed inside some sort of [[Glazing|clear glass or plastic enclosure]] to retain heat and make use of the [[Principles_of_Solar_Box_Cooker_Design#Greenhouse_effect|greenhouse effect]].
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{{Main|Guidelines and cooking tips}}
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==Introductory manuals==
 
<br />
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*[https://www.solarcookers.org/why Solar Cookers: How to Make, Use, and Enjoy] (There are also detailed versions in Arabic ([[Media:CooKit_ar.pdf|Standard]], [[Media:Solar Oven Instructions Arabic.pdf|Variation]]), [[Media:CooKit_french_plans.pdf|French]], [[Media:CooKit Plans detailed Spanish.pdf|Spanish]], and [[Media:Solar_cookit_nairobi_booklet.pdf|English for Kenya]], and [[Media:CooKit - Galician.pdf|Galician]].)
 
::<imagemap>
 
Image:Solar cookers international handbook.jpg|180px|none
 
default [https://www.solarcookers.org/why Solar Cookers: How to Make, Use, and Enjoy]
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desc none
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</imagemap>
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* [[Media:Cookers_english_BD.pdf|Construction of solar cookers and driers]] - ''Christelle Souriau & David Amelin'' (This is an excellent overview of solar cooking basics and simple solar cooker and dryer construction methods.)
  +
::[[File:Solar_orientation,_Construction_of_solar_cookers_and_driers,_Souriau_&_Amelin,_6-9-15.png|thumb|none|400px|Solar orientation, [[Media:Cookers_english_BD.pdf|Construction of solar cookers and driers]], ''Souriau & Amelin'']]
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==Learn more==
 
*[[How solar cookers work]]
 
*[[How solar cookers work]]
 
*[[Where is solar cooking possible?]]
 
*[[Where is solar cooking possible?]]
  +
*{{NewNov19}}[https://www.solarcookers.org/work/capacity/distribution-solar-cookers Interactive map of known solar cooking projects]
*[[The case for solar cooking]]
 
*[[Most significant solar cooking projects]]
+
*[[Why solar cooking is important]]
*[[Media:The Case for Solar Thermal Cooking.pdf|The Case for Solar Thermal Cooking: Free Fuel—Zero Emissions]]
 
*[[United Nations Millennium Development Goals]]
 
 
*[[:Category:Solar cooker plans|Build a solar cooker]]
 
*[[:Category:Solar cooker plans|Build a solar cooker]]
 
*[[:Category:Manufacturers and vendors|Buy a solar cooker]]
 
*[[:Category:Manufacturers and vendors|Buy a solar cooker]]
*[[Health and safety]]
 
*[[How to start solar cooking]]
 
*[[The history of solar cooking]]
 
*[[Solar cooking frequently-asked questions]]
 
 
*[[Introduction & Cooking Tips|Solar cooking tips and tricks]]
 
*[[Introduction & Cooking Tips|Solar cooking tips and tricks]]
*[[Recipes]]
 
 
*[[Cooking guidelines]]
 
*[[Cooking guidelines]]
 
*[[Recipes]]
 
*[[Books|Solar cookbooks]]
 
*[[Books|Solar cookbooks]]
 
*[[Health and safety]]
 
*[[Solar cooking frequently-asked questions]]
 
*[[Most significant solar cooking projects]]
 
*[[United Nations Sustainable Development Goals]]
 
*[[The history of solar cooking]]
 
*[[Emergency preparedness|Solar cooking and emergency preparedness]]
 
*[[Emergency preparedness|Solar cooking and emergency preparedness]]
 
*[[Promoting solar cooking]]
 
*[[Promoting solar cooking]]
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*{{NewJul19}}[[Media:SCI_White_Paper_-_Edward_Ortiz_-_July_2018.pdf|Solar Cookers International White Paper]] - ''Edward Ortiz''
 
==Introductory Manual==
 
<br />
 
<imagemap>
 
Image:Solar cookers international handbook.jpg|180px|none
 
default [[Media:CooKit_plans_detailed.pdf]]
 
desc none
 
</imagemap>
 
[[Media:CooKit_plans_detailed.pdf|Solar Cookers: How to Make, Use, and Enjoy]]
 
 
==Reports==
 
   
 
==Audio and video==
 
==Audio and video==
  +
*{{NewNov20}}'''November 2020:'''
[[Video:Solar Cooking in Africa - A Remarkable Technology Transfer|500px|none]]
 
  +
::[[File:Virtual_Café_Sci-_DARE_to_Solar_Cook_-_The_Physics_of_Cooking_with_Sunshine|thumb|none|400px|DARE to Solar Cook - The Physics of Cooking with Sunshine - ''[[Alan Bigelow|Dr. Alan Bigelow]], Mary Buchenic, and Jennifer Gasser'']]
 
==See also==
 
   
  +
*{{NewOct15}}'''June 2015:'''
*[[Developing an intuitive feel for the dynamics of solar cooking]]
 
  +
::[[File:Star Tides 4 Solar Cookers|thumb|none|400 px|Our last series on the [[STAR-TIDES]] expo in Washington, DC continues with technology available for emergency crisis and [[disaster relief]]. VOA’s Carolyn Turner talked with [[Solar Cookers International]] about their exhibit displaying how to cook with only the sun - ''Voice of America'']]
*[[Media:Pejack_on_solar_cooker_technology.pdf|In-depth look at solar cooking]] - ''Dr. [[Ed Pejack]]''&nbsp;
 
*[[Compendium of solar cooker designs]]
 
*[[:Category:Solar cooker designs|All solar cooker designs]]
 
*[[Principles of Solar Box Cooker Design]]
 
*[http://solarcooking.org/ISES-2005.pdf Affordable Solar Cookers For The Neediest] - ''Beverly L. Blum''
 
   
 
==External links==
 
==External links==
*[http://solarcooking.org/kerr.htm The Expanding World of Solar Box Cookers] - ''[[Barbara Kerr]]''
+
*[http://solarcooking.org/kerr.htm The Expanding World of Solar Box Cookers] - ''[[Barbara Kerr]]'' (This is the full-text of the book by this solar cooking pioneer)
  +
* [[Media:Cookers_english_BD.pdf|Construction of solar cookers and driers]] - ''Christelle Souriau & David Amelin'' (This is an excellent overview of solar cooking basics and simple solar cooker and dryer construction methods.)
 
*Three part series by Sharon Cousins on practical, humanitarian, and environmental aspects and potential uses for solar cooking: [http://valeriecomer.com/?p=1113 Solar Cooking: Clean, Bright and Accessible], [http://valeriecomer.com/?p=1313 Out of the Smoke, Into the Sun], and [http://valeriecomer.com/?p=1438 Cleaner Cooking, Healthier Planet]
   
*Three part series by Sharon Cousins on practical, humanitarian, and environmental aspects and potentials of solar cooking: [http://valeriecomer.com/?p=1113 Solar Cooking: Clean, Bright and Accessible],[http://valeriecomer.com/?p=1313 Out of the Smoke, Into the Sun], and [http://valeriecomer.com/?p=1438 Cleaner Cooking, Healthier Planet]
 
 
[[Category:Introduction to solar cooking]]
 
[[Category:Introduction to solar cooking]]
  +
[[Category:Curated pages]]

Latest revision as of 21:53, 12 October 2023

Searchbox
Last edited: 28 September 2023      

Below you will find an introduction to solar cooking. The Solar Cooking Wiki also provides an individual page for 143 different countries where you will find news, NGOs, manufacturers, and individuals working on solar cooking projects in that country. Links to possible funders are also available:

Country2

Depending on where you live and how you cook, solar cooking can save you time, effort, and fuel. It is also an environmentally friendly and fun way to prepare your meals. All foods can be cooked in some type of solar cooker.

Cooking with a solar box cooker or solar panel cooker is similar to using a slow cooker (crock-pot). Typically, cooking times for these types of cookers are twice that of conventional cooking methods, however, slower cooking also has its advantages. These cookers provide a moderate, even heat, are only reoriented once towards the sun over several hours of cooking, and the food does not have to be stirred during cooking. This frees the cook up to do other useful tasks while the food cooks independently.

Parabolic solar cookers offer another approach to solar cooking by being able to reach higher temperatures and perform more like a traditional stovetop. As such, they require more attention while cooking to avoid burning the food and they need to be turned periodically to follow the sun, depending on cooking time.

For areas in the world experiencing deforestation and limited access to clean water, solar cooking is a valuable part of the solution, by providing a safe, smoke-free alternative method of cooking and pasteurizing water.

Buy or build a solar cooker?

CooKit

The CooKit is an example of a simple solar panel cooker, probably best suited to locations close to the equator

If you are interested in trying solar cooking for the first time, you may be wondering whether you should build your own solar cooker, or to buy one from a manufacturer. There are advantages to both options:

  1. Building your own solar cooker can be a fun and cost-effective way to get started.
  2. A wide variety of solar cookers are available for purchase, and you will often receive a higher-quality cooker than one you might build yourself.

If you would like to build a cooker, visit the build a solar cooker page to choose a design that's right for you. You will find information there comparing the characteristics of each style of cooker.

If you would like to purchase a cooker, check out the list of manufacturers and vendors on the buy a solar cooker page. Commercial cookers are typically durable and efficient, and offer an easy way for new users to experience solar cooking. As cookers are manufactured globally, consider potential shipping costs when selecting a design.

How do solar cookers work?

Solar cookers work on this basic principle: Sunlight is converted to heat energy, that is retained for cooking.

Many solar panel cookers and solar box cookers are capable of reaching 150 °C (302 °F), or higher. The captured solar radiation passes through a greenhouse enclosure enclosing a dark colored cook pot. As it hits the dark surface, the solar radiation is converted to heat, which is contained within the glazing enclosure, and cooking temperatures are achieved. The same principle is often experienced by drivers returning to a hot car that has been parked in the sun. The efficiency of these cookers is typically determined by the amount of reflector area available of the solar cooker to gather sunlight, and the ability of the greenhouse enclosure to receive the available light and help insulate the hot cook pot. Double Pyrex bowls have been shown to work well as greenhouse enclosures for solar panel cookers. See: Glazing for additional enclosure ideas.

Intro-sun
Fuel: Sunlight
Sunlight is the fuel. A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days.
 
Convert sunlight to heat energy

Dark surfaces get very hot in sunlight, whereas light surfaces don't. Cooking is typically best done with dark, shallow, thin metal pots with dark lids to hold in heat and moisture. The thin metal cook pots heat up quickly, but thicker pots will retain heat longer and should be preheated before adding the food.

Intro-pot color
Retain heat

A transparent heat trap around the dark pot lets in sunlight, but keeps in the heat. This is a clear, heat-resistant plastic bag or large inverted glass bowl (panel cookers) or an insulated box with a glass or plastic window (box cookers).

Intro-glazing
Capture extra sunlight

One or more shiny surfaces reflect extra sunlight onto the pot, increasing its cooking potential.

Intro-reflectors
  • Parabolic solar cookers use a bowl shaped reflector to focus the light directly onto the cook pot, usually from below. Typically they do not require a greenhouse enclosure to retain the heat. They reach much higher temperatures than the other styles of solar cookers, usually above 200 °C (392 °F), and also have the ability to fry and broil foods.
SolSource Solar Stove with Cookware

SolSource is an example of a parabolic solar cooker shown with cookware. The light is focused at the bottom of the cook pot.

Industrial scale cooking, Solare Brucke, 6-10-15

Institutional solar cooking can employ many large parabolic reflectors to generate steam, and cook for thousands of people daily. A number of these systems are in use in India. This example, was built with technology from Solare Brücke.


Solar cooker types

The three most common types of solar thermal cookers are box cookers, panel cookers, and parabolic cookers. Hundreds — if not thousands — of variations on these basic types exist. Evacuated tube cookers and trough cookers are two lesser known styles of cooker design. The two approaches are often combined, as the geometry of each is suited to the other. Additionally, several large scale solar cooking systems have been developed to meet the needs of cooking for lerge numbers of people.

Box cookers

All American Sun Oven

All American Sun Oven Solar box cooker

Solar box cookers typically cook food at temperatures between 90 °C (194 °F) and 200 °C (392 °F). They can often accommodate multiple pots, and usually take between one and three hours to cook various foods. The sides and bottom are insulated to retain cooking heat. Worldwide, they are the most widespread. There are several hundred thousand in India alone.

Panel cookers

CooKit photo Make

CooKit panel cooker

Panel cookers incorporate elements of box and parabolic cookers. They often have a large reflector area and the cook pot has some form of clear enclosure to retain heat. Panel cookers are capable of cooking at approximately 170 °C (338 °F). They are the easiest style to make and relatively inexpensive to buy.

Parabolic cookers

AlSol 1

The AlSol 1.4 parabolic cooker demonstrates how the cook pot is supported to receive the focused light from below from the reflector.

Parabolic solar cookers use a bowl shaped reflector to focus the light directly onto the cook pot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. The parabolic name refers to the shape of the curve of the reflector cross-section.

They require more frequent reorientation to the sun, possibly every fifteen minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching temperatures over 200 °C (392 °F). They also have the ability to fry and broil foods. Generally parabolic solar cookers will need to be attended to more than box or panel cookers to avoid possibly burning the food at the bottom of the cook pot. They are especially useful for large-scale institutional solar cooking systems.

Trough cookers

Early GoSun cooker, 2-29-16

The GoSun is an example of a trough solar cooker that also uses an evacuated tube cooking chamber.

For capturing sunlight, trough solar cookers use a reflector with a curved parabolic cross-section, that continues as a straight trough in the other direction. Instead of focusing the light at one spot like a typical bowl-shaped parabolic solar cooker, the light is reflected along what is known as a focal line. These reflectors are easier to fabricate than a parabolic dish, but require a long fairly narrow cooking tray, which is why they work well with evacuated tube enclosures.

Evacuated tube cookers

SLiCK SM70 photo, 8-19-15

The SLiCK SM70 is an example of an evacuated tube style solar cooker.

Evacuated tube literally means that the cooking chamber is constructed of two layers of blown glass in the shape of a sealed tube, where the air has been removed between the layers.

Heat loss often happens by conduction through a medium or by and convection through the air. With no air between the layers of glass, the chamber is nicely insulated, and well suited for retaining cooking heat. The chamber is so effective at insulating it often does not require a large reflector to capture sunlight. A slender cooking tray can be inserted from one end. The opposite end is either sealed with a stopper, or has been sealed during the manufacturing process. Improvements in glass technology is allowing for larger diameter tubes to be fabricated, which will allow larger cooking trays to be inserted inside.

Other types

Beyond performance ratings

Various methods of testing are available to evaluate the performance of solar cookers. Solar Cookers International responded to requests from cooks, manufacturers, and organizations to create an objective, scientific process to evaluate the cooking potential of different cookers, and developed the Performance Evaluation Process (PEP). A number of solar cookers have been tested with this method, and can be seen at PEP tested solar cookers.

Beyond cooking performance, other factors should be considered when designing, purchasing, or building a solar cooker.

  • Cost: The cost of all supplies needed for the solar cooker - including estimated replacement parts needed within five years, compared to the cost of alternative cooking methods and the fuel used in them over five years. Also to consider: Environmental benefits of solar cooking
  • Convenience: The cooker either needs little or no attention during cooking or, the instructions address how often adjustments are needed during a cooking period (for example with parabolic cookers, frequent turning to track the sun or stirring to prevent burning). If movable, is the cooker easy to move and easy to store? What is required to check on the cooking food, and remove it from the cooker when done?
  • Safety: The cooker should be incapable of starting an accidental fire inside or outside the cooker. A warning included that the reflectors remain at ambient temperature, but the cook pots become quite hot. In the case of concentrator cookers, warn of risk for accidentally damaging eyes or burning hands at the focal point. Modern designs usually incorporate a deep parabolic reflector to avoid these types of accidents. See also: Health benefits of solar cooking
  • Cooking capacity: Can the cooker prepare a meal for at least a small family, and/or specify size of family it is intended to cook for? In some cultures it may be important for the cooker accommodate a variety of covered pots and pans to prepare the local cuisine.
  • Durability, maintenance: Repairs should be infrequent, and/or possible to do without special equipment, with replacement parts readily available or easily made DIY. Instructions included for ordinary maintenance or repair as needed (such as wiping off dust from windows and reflective surfaces). Information should indicate expected durability under various weather conditions, and/or guides for protecting it when weather may damage it.
  • Wind stability: The cooker should be reasonably stable in wind to avoid spilling food, or should include instructions to easily make it so (for example; tie-downs or placing rocks in specified places).
  • Instructions: Clear guides for estimated length of cooking time and variables that influence cooking time (food quantity, wind, etc.) See: Guidelines and cooking tips

Using your solar cooker

CooKit photo Make

The CooKit solar panel cooker with a dark pot enclosed in a plastic bag

The golden rule for solar cooking is get your food on early, and do not worry about overcooking. Most people starting to solar cook will be using a solar panel cooker or solar box cooker. These cookers are oriented to the sun and typically don't need to be turned to follow the sun during a 2-4 hour cooking period, though cooking time can be shortened if the cooker is turned.

Once you have decided on a cooker, you will need to find appropriate cookware. Thin-walled dark enameled metal cook pots work well. They are good at heating up quickly. Glass jars can also be used, either clear or preferably painted on the outside. Please note that all cooking vessels need to have a lid, but not be completely sealed to avoid steam pressure build-up. Pots that reflect light, such as silver aluminum pots, will not work as well. Paint these first.

When using a solar panel cooker the pot is normally placed inside some sort of clear glass or plastic enclosure to retain heat and make use of the greenhouse effect.

Introductory manuals


Solar cookers international handbook
Solar orientation, Construction of solar cookers and driers, Souriau & Amelin, 6-9-15

Solar orientation, Construction of solar cookers and driers, Souriau & Amelin

Learn more

Audio and video

  • November 2020:
Virtual_Café_Sci-_DARE_to_Solar_Cook_-_The_Physics_of_Cooking_with_Sunshine

Virtual Café Sci- DARE to Solar Cook - The Physics of Cooking with Sunshine

DARE to Solar Cook - The Physics of Cooking with Sunshine - Dr. Alan Bigelow, Mary Buchenic, and Jennifer Gasser

  • June 2015:
Star_Tides_4_Solar_Cookers

Star Tides 4 Solar Cookers

Our last series on the STAR-TIDES expo in Washington, DC continues with technology available for emergency crisis and disaster relief. VOA’s Carolyn Turner talked with Solar Cookers International about their exhibit displaying how to cook with only the sun - Voice of America

External links