1. The Problem Half the world ’ s people must burn wood or dried dung to cook their food.Half the world ’ s people must burn wood or dried dung to cook their food. Nearly 1.2 billion people, a fifth of the world ’ s population, do not have access to clean drinking water.Nearly 1.2 billion people, a fifth of the world ’ s population, do not have access to clean drinking water. Over 1 million children die yearly because of un-boiled drinking water.Over 1 million children die yearly because of un-boiled drinking water. Wood cut for cooking purposes contributes to the 16 million hectares of forest destroyed annually.Wood cut for cooking purposes contributes to the 16 million hectares of forest destroyed annually. Half the world ’ s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating.Half the world ’ s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating.

2. Box cooker Among easiest and most popular to build and use Lid of a cardboard box reflects light onto pots under glass Advantage of slow, even cooking of large quantities of food

3. Panel Cooker Sunlight is reflected off of multiple panels onto a pot under a glass lid or in a bag Can be built quickly and at low cost Many different varieties

4. Solar Funnel Cooker Safe, inexpensive and easy to use Concentrates sunlight into a dark pot in a plastic bag Combines best of parabolic and box cookers Anyone can make one

5. Parabolic Cooker Highly focused light and high temperatures Cooks nearly as fast as a conventional oven Costly and complicated to make and use – have to turn frequently to follow the sun Potentially hazardous-not recommended

6. The basic principles - C.A.R.E.S. C ollect the lightC ollect the light A bsorb the lightA bsorb the light R etain the heatR etain the heat E ase and EfficiencyE ase and Efficiency S afetyS afety

7. C: Collect the Light Collect the sunlight using reflectors with an approximately 400 square inch opening (20x20)Collect the sunlight using reflectors with an approximately 400 square inch opening (20x20) Easy way to measure: the minimum opening of the cooker needs to be the diameter of an adult ’ s armEasy way to measure: the minimum opening of the cooker needs to be the diameter of an adult ’ s arm Reflective surface materials include: aluminum, Mylar, aluminized Mylar of any thickness, aluminum or chromium paint (Note: mirror like reflectors can lead to eye damage)Reflective surface materials include: aluminum, Mylar, aluminized Mylar of any thickness, aluminum or chromium paint (Note: mirror like reflectors can lead to eye damage)

8. A: Absorb the light Absorb the light – paint the pot matte black or another dark color to absorb the heatAbsorb the light – paint the pot matte black or another dark color to absorb the heat Pots can also be elevated by a wire base or posts, allowing the bottom of the pots to collect sunlightPots can also be elevated by a wire base or posts, allowing the bottom of the pots to collect sunlight

9. R: Retain the Heat Retain the heat – hot vessels lose their heat to the air quickly so they need to be coveredRetain the heat – hot vessels lose their heat to the air quickly so they need to be covered Cover with plastic, glass, Plexiglas, or tempered glassCover with plastic, glass, Plexiglas, or tempered glass A tight lid will trap steam and speed up cooking Ex: Canning jars work like inexpensive pressure cookersA tight lid will trap steam and speed up cooking Ex: Canning jars work like inexpensive pressure cookers

10. R: Retain the Heat A note on plastics Oven bags are the best way to retain heat. They are sold in most large U.S. grocery stores, although they may be hard to find in other places (Reynolds © bags work well)Oven bags are the best way to retain heat. They are sold in most large U.S. grocery stores, although they may be hard to find in other places (Reynolds © bags work well) If you can ’ t find oven bags, an alternate solution is transparent High Density Polyethylene bags (HDPE)If you can ’ t find oven bags, an alternate solution is transparent High Density Polyethylene bags (HDPE) Prevent the HDPE bags from touching the pots or jars, as they may meltPrevent the HDPE bags from touching the pots or jars, as they may melt Avoid polyethylene – it melts too easilyAvoid polyethylene – it melts too easily Good plastic may be the most difficult material to find, and may require extra planning, possibly including importing the oven bagsGood plastic may be the most difficult material to find, and may require extra planning, possibly including importing the oven bags

11. E: Ease and Efficiency Ease – simplicity of everyday use Funnel and box cookers are the easiest to use – they don ’ t have to be turned to follow the sunFunnel and box cookers are the easiest to use – they don ’ t have to be turned to follow the sun Efficiency - how fast the cooker heats food Parabolic cookers focus light to a point (most efficient) causing dangerous conditionsParabolic cookers focus light to a point (most efficient) causing dangerous conditions Funnel cookers focus light across a broader area down the center of the cooker (efficient but not dangerous)Funnel cookers focus light across a broader area down the center of the cooker (efficient but not dangerous)

12. S: Safety S afety – Avoid highly focused light such as that in the parabolic cooker. It can damage eyes and start firesS afety – Avoid highly focused light such as that in the parabolic cooker. It can damage eyes and start fires Always exercise caution with cookers. Sunglasses are useful when looking into a cookerAlways exercise caution with cookers. Sunglasses are useful when looking into a cooker Cooking pots are hot and should be treated as though they were on a stove-topCooking pots are hot and should be treated as though they were on a stove-top