The solar oven for the garden or terrace

Cooking with the solar oven

Those who love cooking outdoors can not ignore the existance of the solar oven, an object that for the simplicity that distinguishes it can be made by anyone with a minimum of manual skills by spending a small amount of money and dedicating only a few hours of work.

Useful when you want to cook in the garden, the solar oven becomes essential in places where the sun is one of the few resources available for boiling and consequently sterilize water.

Solar oven and solar kitchen

We must first clarify the difference between solar oven and solar kitchen: they both exploit solar energy, but while the first is constituted by a box and work thanks to the greenhouse effect that is created inside, the second is comparable to a portable stove, provided with a parabola able to concentrate sunlight in one point.

Some examples of solar ovens

One of the best known solar oven is definitely the one called Kyoto box, by the Norwegian Jon Bohmer, that use only two cardboard boxes and a transparent panel. The advantage of the Kyoto box is very easy to carry and quick to produce. Just fold the edges to the instructions and in a moment the oven is ready.

Solar ovens are classified for the ability to harness the light intensity, also called efficiency. The Kyoto box, being made entirely of cardboard, falls into the category of low efficiency solar ovens and can reach at most a temperature of about 100 degrees, depending on where it is used.

The solar oven, however, can achieve the levels of a traditional oven if built with the right materials and the right precautions. The prototype of solar furnace high efficiency built by Ottavio Tarabelloni measures two meters high by two meters in length, carries like a common wheelbarrow and is able to reach also 250 degrees.

The footprint of this type of furnace makes it suitable mainly in certain contexts, such as houses or summer camps, but those who want to build their own garden can follow the advice and technical drawings made available freely on the internet by the author of the book Solar Oven for cooking .



Obviously, the efficiency of a solar furnace does not depend only on the quality of the materials used and the skill to realize it, but also by climatic conditions; in the best conditions the sky must be clear and free of clouds that may filter the solar rays, otherwise the efficiency of the oven will be less.

How to build a solar oven to medium efficiency

Portable solar ovens typically fall into the category of medium-efficiency furnaces. A solar oven of medium efficiency can reach up to 180 degrees, for giving a parameter is the minimum temperature required to bake bread. The small dimensions mean that it is easy to transport and perfect to accompany as necessary the barbecue in the garden.

Material needed to build the solar oven

Tentatively to build a solar oven portable media efficiency requires two days of work and the following material:

-Three Plywood panels marine 60X60 cm by 12 mm thick. Wood Okum is ideal to withstand wet environments without deterioration

-Screws and metal plates to fix the reflective panels, straight and L to 120 degrees

-Grill and metal rods, preferably made of brass so that they do not oxidize

-A glass quite thick of 70x60 cm, equipped with a knob for maneuver

-Aluminum thin slabs or in paperboard for kitchen coated to realize the external reflective panels

-Metal black sheet to apply inside the oven

-An insulating mat in rock wool or rigid polystyrene panels 4 cm

-Wooden handles to move the oven without burning.



Once you have cut the wood panels as illustrated to optimize the material and not needlessly wasting wood, you have to join the pieces and build the structure. The form that is usually used is the trapezoid with angles of 30° to 60° and 90°, in such a way as to follow the position of the sun only changing support base. The grid inside will rotate on itself supported by the pin and retains the content of the furnace in a horizontal position.

Subsequently you need to cut the insulation panels to the size of the inner sides of the box and line the whole with a black metal or cardboard kitchen coated aluminum to be painted subsequently.
As lid must cut to fit a glass quite thick, giving it the top with a knob as you remove it easily.

A solar oven is all the more efficient as more sunlight it is able to convey inside the box, therefore the last step is to equip the furnace reflective panels of thin metal sheet. To fasten them you need the brackets, both straight and of 120 degrees, to be applied as in the picture.

Who tried to cook with the sun says that the flavor of the food is different, especially vegetables that are under ground, like carrots or potatoes: try it!