A solar cooker consists essentially of a well-insulated box with a window (glass or plastic), through which sunlight can pass. Within the box, sunlight is absorbed by the black base and walls (offset plate) or by the dark cooking pots, that is to say, the solar energy is converted into heat. Temperatures of up to 170°C can be achieved with this method.
Advantages of the solar cooker
- Solar cookers are very simple and cheap to make, and the units require practically no maintenance. The cookers have useful lives of about 20.
- Cooking with the solar cooker is free. This means fuel costs can be saved, so the initial cost of the cooker is quickly paid off.
- Solar cookers are suitable for boiling, baking, simmering, making fruit and vegetable preserves, drying, sterilising water or medical equipment.
- Dishes are cooked and bread is baked to perfection. Cooking pots can neither burn nor boil over, and consequently do not need constant supervision. This also saves time.
- The deforestation of threatened forests is slowed, and CO2 emissions are reduced, because less wood is burned.
- In many southern, economically poor countries with high levels of sunshine, solar cookers are a genuine survival support, both for people as well as for the forests and fauna.
Disadvantages of the solar cooker
- The solar cooker is particularly suitable for countries with high levels of sunshine and long sunlight hours (above all in the subtropics and at high altitudes )
- Cooking time is roughly twice that of conventional cookers, although the labour-saving nature of the solar cooker makes up for this.
- Changing cooking habits away from the open fire to a closed solar cooker is the greatest difficulty when it comes to introducing solar cookers in developing countries. Nevertheless, this new, environmentally-friendly cooking technology has already been successfully introduced in many regions. (see Projects)
In addition to the basic "cooking box" or "solar oven" type, there are many other models, e.g. with parabola reflectors, a combination of both types, funnel reflectors, drum cookers (made from half oil-drums). Basic method special models for drying, see Manufacturing.