Solar Ovens
Table of Contents
Introduction
Solar ovens work well in places that receive ample sunlight, so this solution may not work as well if you live in a place with shorter daylight hours, lots of tall trees or surrounded by tall buildings.
Impact
As you can see in the graph beneath, cooking accounts for only a small percentage of home energy use in countries like America, however cooking energy can account for the majority of a household's energy use and pollution in places like Africa where less clean fuels such as wood fires are often used.Â
Types of Solar Cooking
There are two primary ways to cook directly with solar energy.
Solar Ovens will work best in countries closer to the equator, on sunny days. They can't be used at night, and the efficiency is hard to control due to their reliance on natural direction and intensity of light.
Solar Dehydrators use ventilation and solar energy to dehydrate foods that might otherwise go to waste. This is a good method for herbs, chilis, tea leaves, mushroom, vegetables, and fruits.
If you have access to solar panels or a utility company that offers renewables such as solar, you can also use electric devices powered by solar.
Sun Drying Resources
Why Sun Dry Fruits & Vegetables Lists health benefits and a short list of appropriate foods for sun drying.
National Center for Home Food Preservation: Drying This resource page talks explains which foods can safely be dried outside, vs which should be preserved indoors with more a more easily controlled environment. It then explains methods and equipment including a diagram.
Solar Dehydrator Resources
Solar Oven Resources
Kitchen Appliances
Use an electric kettle or microwave to heat water or other liquids. These are much faster and more efficient than heating on a stove.
Microwaves are fast, energy efficient, and can save water. Microwaves are amazing for heating potatoes. You just take off any unhealthy looking parts on or under the skin, stab the potato with a fork or knife a few times, and heat on a microwave-safe plate for ~3 minutes on each side for large potatoes. Cook for longer if you have a large bowl of potatoes for roasting or mashing.
Electric stove tops don't leak dangerous gases while they are off, like gas stoves do. They are also more efficient, only heating the pot or pan on each circle, will less space for heat to escape then the earlier oven models.
Efficiency Tricks
By Food Type
Microwave Potatoes to save time and the environment. You can make potatoes saltier and tastier by boiling them (do this before roasting them in an oven), but if you just want potatoes for mashing, or are going to put the potatoes into something like a curry or stew, then this can save energy and water. Acidic sauces with ingredients like lemon juice or tomato sauce will stop certain foods like potatoes from cooking even after many hours of heating. Boiling in water usually takes around 30 minutes, but you can put 1-3 potatoes and microwave them for about 1:30 -3:30 on each side till they are soft when tested with a fork. Skin off any damaged skin or weird looking pieces of potatoes, and stab each potato a few times on each side to let the internal juices escape as steam.
Squeeze your raw potatoes (or other roots) before making hash browns as this not only ensures they are crunchier, but they seem to cook faster too.
Tips for Success
Equipment with Doors
Keep oven doors shut as much as possible, otherwise you loose heat, and things will take longer to cook.
Pots & Pans
If using a pot, keep the lid on pot the pot to reduce energy needs and speed up the cooking process. If you are trying to "reduce" your food, then leave the lid off, and you may want to leave the lid off or to the side to allow steam escape if you want something like a pudding to set instead of going watery as it cools.
Solar Dehydrators & Ovens
Install or use a nearby fan for increased air flow if your food is not drying reasonably well or evenly. Alternatively you may be able to simply move the dehydrator to a location with better air flow, perhaps away from a wall or bushes, and into a more open area or the edge of a balcony.
Make sure your solar cooker or dehydrator is angled towards the sun. As the sun moves across the sky, the device may become more shaded or catch less direct light as the sun's angle changes.
This Technology Pairs Well With...
Warming Baskets
These go by many names but most of the information we have found on these suggests that they save between 70-80% on cooking fuel (such as wood or gas), since the food only needs to be brought to a boil before being taken off the heat and placed inside the device where it cooks via retained heat for 30 minutes or a certain number of hours depending on the food being cooked.
In the old days, people also made these out of wood or metal. The main principal being that heat from warmed food or water would remain inside, continuing the cooking process even without applied heat. Modern examples are woven baskets or other insulative items, lined with newspaper, then insulated with a fiber such as cotton or wool, then re-lined with a black material. This material is sewn down to create a space for a cooking pot. An insulated, cloth lid it created to help keep warmth inside.Â
Apps & Resources
Calculating Your Impact
Click the link below for access to multiple calculators based on different cooking methods, and different amounts of food.
Projects
This section is for projects designed to help others. You can help fund them, or even join as an educator for example.
Africa
Kenya
Unterstützung von Warmhaltekorb-Präsentationen in Afrika "Förderung von Warmhaltekorb-Workshops und -Präsentationen zur Unterstützung der Verbreitung von Solarkochern und zur Minderung der Entwaldung in Kenia."
(translated to ->) Supporting Warming Basket Presentations in Africa  "Promote warming basket workshops and presentations to support the spread of solar cookers and reduce deforestation in Kenya."
Organizations
Africa
Uganda
A Rocha Uganda "Training women to make briquettes & fireless cookers: saving money & trees"
