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Below you will find information about how solar cookers work. 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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==How do solar cookers work?==
 
==How do solar cookers work?==
Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is retained for cooking.
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Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is used for cooking.
   
Below is the basic science for [[solar panel cookers]] and [[solar box cooker]]s. The other main variety of cookers are called [[parabolic solar cooker]]s. They typically require more frequent reorientation to the sun, but will cook more quickly at higher temperatures. They also have the ability to fry foods.
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Below is the basic science for [[solar panel cookers]] and [[solar box cooker]]s. Another style of solar cooker is a [[parabolic solar cooker]]. They typically require more frequent reorientation to the sun, but will cook more quickly at higher temperatures, and can fry foods. [[Evacuated tube solar cooker designs|Evacuated tube solar cookers]] use a highly insulated double-wall glass tube for the cooking chamber, and do not require large reflectors.
   
[[File:Solar_Cooking_basics,_SCI_2004,_pg._1,_12-9-14.png|none|600px]]
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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, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall.
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<td>[[File:Intro-sun.gif|thumb]]</td>
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<td>'''Fuel: sunlight'''<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">'''Convert sunlight to heat energy'''<br />
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Dark surfaces get very hot in sunlight, whereas light surfaces don't. cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture.
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[[File:Intro-pot_color.gif|center]]
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A solar cooker needs an outdoor location 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, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall.
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</td></tr>
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<tr><td colspan="2">'''Retain heat'''<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>
   
[[File:Solar_Cooking_basics,_SCI_2004,_pg._2,_12-19-14.png|none|600px]]
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<tr><td colspan="2">'''Capture extra sunlight'''<br />
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One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potentional.
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[[File:Intro-reflectors.gif|center]]
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</td></tr>
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</table>
   
*[[Parabolic solar cooker]]s use a bowl shaped reflector to focus the light more directly onto the cook pot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. They also have the ability to fry and broil foods.
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*[[Parabolic solar cooker]]s use a bowl-shaped reflector to focus the light more directly onto the cookpot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. They can also fry and broil foods.
::[[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 focussed at the bottom of the cook pot.]]
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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 cookpot.]]
 
[[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. Many of these systems are in use in [[India]]. This example, was built with technology from [[Solare Brücke]].]]
 
[[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. Many of these systems are in use in [[India]]. This example, was built with technology from [[Solare Brücke]].]]
 
{{clr}}
 
{{clr}}
 
===Converting sunlight to heat energy===
 
===Converting sunlight to heat energy===
At its simplest, the sunlight-to-heat conversion occurs when photons (particles of light) moving around within light waves interact with molecules moving around in a substance. The rays emitted by the sun have a lot of energy in them. When they strike matter, whether solid or liquid, all of this energy causes the molecules in that matter to vibrate. They get excited and start jumping around. [[Principles_of_Solar_Box_Cooker_Design#Heat_gain|This activity generates heat]].
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At its simplest, the sunlight-to-heat conversion occurs when photons (particles of light) moving around within light waves interact with molecules moving around in a substance. The rays emitted by the sun have a lot of energy in them. When they strike matter, whether solid or liquid, all of this energy causes the molecules in that matter to vibrate. [[Principles_of_Solar_Box_Cooker_Design#Heat_gain|This activity generates heat]].
   
 
Dark surfaces get very hot in sunlight, whereas light surfaces don't. While food cooks best in dark, shallow, thin metal [[pots]] with dark, tight-fitting lids, there are many other containers that can also be used in a solar cooker.
 
Dark surfaces get very hot in sunlight, whereas light surfaces don't. While food cooks best in dark, shallow, thin metal [[pots]] with dark, tight-fitting lids, there are many other containers that can also be used in a solar cooker.
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===Capturing extra sunlight energy===
 
===Capturing extra sunlight energy===
One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used.
+
One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, Mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used.
 
{{Main|Reflective material}}
 
{{Main|Reflective material}}
   
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The three most common types of solar cookers are [[box cookers]], curved concentrators ([[Parabolic cookers|parabolics]]) and [[panel cookers]]. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.
 
The three most common types of solar cookers are [[box cookers]], curved concentrators ([[Parabolic cookers|parabolics]]) and [[panel cookers]]. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.
   
===<u>Box cookers</u>===
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===Box cookers===
[[File:All American Sun Oven image, 12-11-13.jpg|thumb|200px|[[All American Sun Oven]] [[Solar box cooker]]]]
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[[File:All American Sun Oven.jpg|thumb|200px|[[All American Sun Oven]] [[Solar box cooker]]]]
 
Box cookers cook food at moderate to high temperatures and often accommodate multiple pots, typically taking between one and three hours to cook various foods. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
 
Box cookers cook food at moderate to high temperatures and often accommodate multiple pots, typically taking between one and three hours to cook various foods. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
 
{{Main|Solar box cooker designs}}
 
{{Main|Solar box cooker designs}}
   
===<u>Panel cookers</u>===
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===Panel cookers===
[[Image:Panel-type.jpg|right|200px|woman with panel cooker]]
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[[File:CooKit_photo_Make.jpg|thumb|200px|[[CooKit]] [[panel cooker]]]]
 
Panel cookers incorporate elements of box and parabolic concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "[[CooKit]]" is the most widely used combination cooker.
 
Panel cookers incorporate elements of box and parabolic concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "[[CooKit]]" is the most widely used combination cooker.
 
{{Main|Solar panel cooker designs}}
 
{{Main|Solar panel cooker designs}}
   
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===Parabolic cookers===
===<u>Parabolic cookers</u>===
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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 cooker]]s use a bowl shaped reflector to focus the light more 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.
[[Image:AlSol 1.4.jpg|thumb|300px|An [[AlSol 1.4]] parabolic cooker demonstrates where the cook pot is supported to receive the focussed light from below from the reflector.]] [[Parabolic solar cooker]]s use a bowl shaped reflector to focus the light more 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 will require more frequent reorientation to the sun, possibly every 10 minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching over 200°C (400°F). They also have the ability to fry 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 cooking.
 
They will require more frequent reorientation to the sun, possibly every 10 minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching over 200°C (400°F). They also have the ability to fry 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 cooking.
 
{{Main|Parabolic solar cooker designs}}
 
{{Main|Parabolic solar cooker designs}}
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  +
===Evacuated tube solar cooker designs===
  +
[[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]] solar cooker.]]
  +
[[Evacuated tube solar cooker designs|Evacuated tube solar cookers]] use a double-wall glass tube for the cooking chamber. The space between the glass is created as a vacuum, providing excellent heat retention. While efficient, glass technology somewhat limits the size of opening of the glass tube, requiring smaller cooking pots.
  +
{{Main|Evacuated tube solar cooker designs}}
   
 
==See Also==
 
==See Also==
*[[Introduction to solar cooking]]
 
 
*[[Principles of Solar Box Cooker Design]] - ''Mark Aalfs''
 
*[[Principles of Solar Box Cooker Design]] - ''Mark Aalfs''
 
*[http://images2.wikia.nocookie.net/__cb20080215180446/solarcooking/images/3/3a/Pejack-on-solar-cooker-technology.pdf The Technology of Solar Cooking] - ''[[Ed Pejack]]''
 
*[http://images2.wikia.nocookie.net/__cb20080215180446/solarcooking/images/3/3a/Pejack-on-solar-cooker-technology.pdf The Technology of Solar Cooking] - ''[[Ed Pejack]]''
 
*[[:Category:Solar cooker designs|All solar cooker designs found on this wiki]]
 
*[[:Category:Solar cooker designs|All solar cooker designs found on this wiki]]
  +
*[[Introduction to solar cooking]]
 
*[[Why solar cook]]
 
*[[Why solar cook]]
 
*[[Where solar cook]]
 
*[[Where solar cook]]
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==External links==
 
==External links==
  +
*{{NewFeb17}} [https://www.desmos.com/calculator/y90ffrzmco Parabola-Focus-Directrix: interactive parabolic curve calculator]- ''Jose Antonio Gutierrez Guerra''
 
* [http://www.isf-cameroun.org/sites/default/files/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.)
 
* [http://www.isf-cameroun.org/sites/default/files/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.)
 
*[http://www.ccathsu.com/files/uploads/Parabolic-Solar-Cookers.pdf Parabolic Solar Cookers] - ''Humboldt State University''
 
*[http://www.ccathsu.com/files/uploads/Parabolic-Solar-Cookers.pdf Parabolic Solar Cookers] - ''Humboldt State University''

Latest revision as of 18:20, January 19, 2020

Last edited: 19 January 2020      

Below you will find information about how solar cookers work. The Solar Cooking Wiki also provides an individual page for 141 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

How do solar cookers work?Edit

Most solar cookers work on the basic principle: Sunlight is converted to heat energy, that is used for cooking.

Below is the basic science for solar panel cookers and solar box cookers. Another style of solar cooker is a parabolic solar cooker. They typically require more frequent reorientation to the sun, but will cook more quickly at higher temperatures, and can fry foods. Evacuated tube solar cookers use a highly insulated double-wall glass tube for the cooking chamber, and do not require large reflectors.

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. cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture.

Intro-pot color

A solar cooker needs an outdoor location 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, though during the best months for cooking, many foods can be cooked under intermittent clouds or a light haze, as long as food is put out early and there is definitely more sun than not overall.

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 heat potentional.

Intro-reflectors
  • Parabolic solar cookers use a bowl-shaped reflector to focus the light more directly onto the cookpot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. They can also 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 cookpot.

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. Many of these systems are in use in India. This example, was built with technology from Solare Brücke.


Converting sunlight to heat energyEdit

At its simplest, the sunlight-to-heat conversion occurs when photons (particles of light) moving around within light waves interact with molecules moving around in a substance. The rays emitted by the sun have a lot of energy in them. When they strike matter, whether solid or liquid, all of this energy causes the molecules in that matter to vibrate. This activity generates heat.

Dark surfaces get very hot in sunlight, whereas light surfaces don't. While food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids, there are many other containers that can also be used in a solar cooker.

Main article: Pots

Retaining heatEdit

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

Light passes through the plastic bag or glass cover as a relatively short wavelength. Heat is reflected back as a longer wavelength, and does not easily pass back through the clear enclosure. This explains why cars left in the sun, especially those with black interiors, will slowly become hotter and hotter, even on days with low air temperatures.

Parabolic solar cookers typically do not require a heat trap, as the light from the reflector is tightly focused on the cook pot. They cook at higher temperatures, but require more frequent reorientation with the sun than box or panel cookers.

Main article: Glazing

Capturing extra sunlight energyEdit

One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential. Mirrors, aluminum foil, Mylar, mirror-finish metals, chrome sign vinyl, and other shiny materials have all been used successfully for solar cooking, depending on the type of cooker and the environment in which it will be used.

Main article: Reflective material

Solar cooker typesEdit

The three most common types of solar cookers are box cookers, curved concentrators (parabolics) and panel cookers. Hundreds — if not thousands — of variations on these basic types exist. Additionally, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.

Box cookersEdit

All American Sun Oven

All American Sun Oven Solar box cooker

Box cookers cook food at moderate to high temperatures and often accommodate multiple pots, typically taking between one and three hours to cook various foods. Worldwide, they are the most widespread. There are several hundred thousand in India alone.

Panel cookersEdit

CooKit photo Make

CooKit panel cooker

Panel cookers incorporate elements of box and parabolic concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "CooKit" is the most widely used combination cooker.

Parabolic cookersEdit

AlSol 1.4

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 more 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 will require more frequent reorientation to the sun, possibly every 10 minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching over 200°C (400°F). They also have the ability to fry 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 cooking.

Evacuated tube solar cooker designsEdit

SLiCK SM70 photo, 8-19-15

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

Evacuated tube solar cookers use a double-wall glass tube for the cooking chamber. The space between the glass is created as a vacuum, providing excellent heat retention. While efficient, glass technology somewhat limits the size of opening of the glass tube, requiring smaller cooking pots.

See AlsoEdit

External linksEdit

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