Types of Solar Cookers

Solar cookers are the cheapest way of harnessing the sun's energy. They work with no or very little complex circuitry, therefore they have little chance of malfunction. Most types of solar cookers works on the principle of reflection and concentration. It can be reflected concentration where multiple surfaces reflect sunlight on to a single area or concentration from multiple sources to same area, where different lens like objects concentrate sunlight at a given spot.

Reflected Concentration Method

The most commonly used reflective surface is any concave surface or a group of glass panels arranged in such a way as to concentrate the reflection on to an area. This principle is very effective and cheap to implement. The raw materials required for building such a cooker can be found in most back yards. 

Reflected concentration produces heat according to the surface area of the reflecting material.A major disadvantage of this method is that the heat stops as soon as the sun goes down. 

This method is being used widely for making solar cooker and even large solar power electricity generating plants. The beauty of this method is its simplicity of design and ease of construction.  

Trapped Heating 

Another type of solar cooker are based on the green house principle where a dark heat absorbing surface is enclosed in a greenhouse chamber. The build quality highly determines the temperature.  This principle does not attain very high temperatures but provide medium temperatures for longer duration. 

The insulation of the thermal box is very important and also the quality of the heat absorbing material. Such solar cookers are also cheap to build as wood, wool, glass and black paint can build good quality solar cookers that work on this principle. 

Trapping heat is most commonly applied for solar water heaters. Cookers can also be made from this principle but cooking will be slow, how ever they are more commonly used as hot boxes than for cooking. In different parts of Rwanda you can find solar cookers being used as hot boxes for storing Samosas and other eatables. This is a result of the co-operation between the solar sisters and the local artisans (Go here to read more about Rwanda and its artisans)  

Converted Heating 

Very in efficient yet provide quick heating, this involves first converting the solar energy into electricity and then using it to heat coils. This method provide very fast heating but it is very in efficient and more over very expensive. 

This is used in some remote clinics etc to sterilize products etc. This method is not very common and not at all popular in the masses. 

Heat concentration 

This involves concentrating heat using lenses, water etc. This method produces extremely high temperature to the tune of 1000 of degree centigrade. This method is hardly used as a solar cooker model as it is usually expensive. The method can be seen used at the Tirupati temple in South India where it is being used to boil milk used for preparing the sacrificial offerings. 

These are the different types of solar cooker that are commonly used. There are hybrids which are based on one or more of these types.