This is a guide to different kinds of solar cookers. I’ve worked with these fun little devices myself, on models used by NGO’s (Non-Governmental Organizations) to help feed the poor in Africa.
Solar cookers are cheap to make and need only sunlight to cook food or purify water. With all the direct sunlight Africa receives, this is a good fit. They also reduce deforestation, and the hazards that come from having wood stoves in densely populated areas.
But solar cookers aren’t just for the poor. They are a fun DIY project that can increase your energy independence, giving you another option for cooking food if you ever lose power. They’re helpful if you spend a lot of time in the wilderness as well. This article reviews some of the more popular commercial solar cookers, which might give you some guidance about which DIY project to select.
Let’s take a look at how they work, and the different kinds of solar cookers you can make.
The 4 Principles Solar Cookers Use to Cook Food
There are 4 principles incorporated by solar cookers to reach temperatures high enough to cook food. They are:
- The Greenhouse Effect: Like a greenhouse, a solar cooker lets thermal energy (sunlight) into the device, and does a good job at keeping it there.
- Concentration of Sunlight: Like a magnifying glass, solar cookers collect sunlight and direct it onto a small cooking area.
- Heat absorption: The cooking area is often made a dark color, so once the sunlight is directed there it absorbs it and heats up.
- Insulation: With all that heat focused on the cooking spot, it is important to keep it there and not have it escape the device.
Using these 4 principals, solar cookers can reach temperatures that sometimes match regular ovens.
Now let’s look at some of the different designs we can make.
3 Kinds of Solar Cookers
The most effective models, these use the parabola shape to direct different streams of sunlight and focus them on a single cooking spot. They can very often reach temperatures similar to that of regular ovens.
They are often used for large scale cooking and pop up all of over the place in China.
Because of the shape of parabola cookers, they are difficult to produce, and as such are the most expensive. They also require some skill to use.
A cool, cheaper alternative is to turn an old umbrella, with its parabola shape into a cooker. For a step-by-step guide to making one, go here.
A second option is a box cooker. Insulated boxes with dark interiors and transparent tops, these devices incorporate all four principals to cook their food. They can often reach up to 150 degrees, not quite oven temperature territory but good enough to purify water and cook most food slowly. To learn how to make one of these, go here.
The cheapest models (you can often buy one for under $5), they use reflective panels to direct sunlight onto a single cooking point. Food is often cooked in a black pot, inside or a sealed plastic bag, to maximize temperatures.
These are the least effective cookers, but can still purify water, pasteurize milk and cook grains like rice. To learn how to make one of these, go here.
How to Cook With a Solar Cooker
Solar cookers take longer to cook than regular ovens. How long they take depends on many factors, such as:
• The quality of the model
• The type of food you are cooking
• How much direct sunlight you receive
• The time of year
• Your latitude
Set your solar cooker up by 10 am to directly face the equator (south in the Northern Hemisphere, north in the Southern Hemisphere). This will maximize the amount of direct sunlight your cooker receives. Leave it alone to work its magic, checking back every hour to see the progress.
I hope you have fun with these solar cooker designs. I know I did!
Good luck and stay prepared!
Guest post by Rambo Moe.