1. Catching the solar beam as much as possible
2. Keeping the collected solar energy as much as possible With the above features, anyone can make solar cookers with inexpensive materials. Solar Cookers are generally categorized into three types: A. Concentrator Type
<Features>
Curved reflector, mostly in parabolic shape, with the ample area can collect solar light effectively and heat up a pot to the cooking temperature quickly. The heating power varies according to the projection area receiving the sunlight. In this system, due to some energy loss, about 20% out of the total collected energy is used for heating up water (the loss by air convection is about 45%, the loss by evaporation heat is about 35%).
However, the heating power is sufficient enough to be comparable to a normal portable cooking stove.
<Style of possible cooking >
All styles of cooking such as baking, boiling, steaming, frying are possible.
<Price>
Although the price depends on the materials to be used, making a curved reflector with a large surface generally costs us more than that with a non-curved reflector.
B. Box Type
<Features>
The feature of box type solar cooker is to keep collected heat as much as possible. The box with the high insulation will capture the solar beam and heat up the pot with the entire inner air like an oven. The countries, which are located near the equator, such as Africa and India can enjoy strong sunshine from high altitudes all year round and can cook without reflectors. Whereas the countries which cannot expect strong sunshine all the time need booster mirrors as a complementary reflector but require fewer frequency of adjustment of the angle than the concentrator type cooker.
<Style of possible cooking>
The cooker is not good at searing but is able to cook and boil it.
<Price>
In many cases, they are easy and inexpensive to be produced compared with concentrator type solar cookers.
C. Panel Type
<Features>
The simple cooker which consists of a combination of plane reflectors is called the panel type. Sometimes the cooker with bent panels are also referred to the panel type. A pot needs to be kept warm by a heatproof plastic bag, a plastic case, or a glass made cover. The heating power and the way of cooking is almost the same as those of box type.
<Style of possible cooking>
The possible cooking style would be almost the same as the box type.
<Price>
The cooker is easy and less expensive to be produced by using common materials such as cardboard so that the people in developing countries can utilize it with little burden to their family budgets.
A’. Balloon Type (film reflection type)
<Features>
The balloon type is one of concentrator type solar cookers. Its advantage is that the manufacturing cost would be considerably low when the aperture of the reflector is large, compared with conventional concentrator type cookers.
By this reason, it is more suitable when used as a community cooker at places such as hospitals and schools. It also features a high portability by releasing air inside the cooker.
<Style of possible cooking>
All styles of cooking such as baking, boiling, steaming, and frying are possible.
<Price>
This cooker is inexpensive because it is entirely made of synthetic materials including the reflector itself and this allows the production in large amount at lower costs compared with cookers with metal sheets such as aluminum or stainless steel.
In addition, it can reduce not only material costs but also shipping costs by packaging it in flat shape by releasing the air inside.