Concentrating Solar Cookers

Earlier we have seen the solar box Cookers. Now we will discuss about the Concentrating Solar Cookers also Known As Parabolic Solar Cookers.

This type of solar cookers are very much used in all over the world due to the faster cooking ability. They are also known as solar dish cookers. As per the constructional point of view there are many design available in this type of solar cookers.

Main Parts Of Concentrating Solar Cookers
As per the figure you can have a idea about the simple construction of concentrating solar cookers. The main Parts are
Reflecting Structure: Mainly all concentrating solar cookers are made with parabolic shape in circular or rectangular profile. Reflecting material can be anodized aluminium sheet, reflecting mirror or any other reflecting media with reflectivity more then or equal to 90. This will reflect all the sun rays to one focal point known as focus of the parabola.

Cooking Pot: At the focus of the parabola the heat is maximum due to concentration of the sun rays. The cooking pot is kept at the focal point so that maximum heat can be utilized. In this type of cookers the temperature can go beyond the 250 deg cel. Due to this it can be used for frying also. which is not possible in the box cooker or in panel cooker. The proper pot holder is provided at the focus of parabola.

Support Structure: This is the structure on which the complete parabolic cooker rest and perform its operation. It must have Rigid structure to withstand the higher wind velocity and also it should be protected with the corrosion resistance paint/ Coating.

Castor Wheel or Tracking Mechanism: This type of solar cookers require continuous tracking along with the rotation of the sun. So there is automatic tracking or the wheel is provided for the manual tracking.

How It Works: It concentrates all the sun ray at one focal point due to this the temperature is higher at the focal point where the cooking pot is kept. this can boil one ltr of water in just 9-10 minutes.

Advantages:
>>The cooking is very fast compared to Box Cookers And Panel Cookers.
>>The frying and making Chapaties is also possible.
>>Other commercial use like melting of wax, boiling of fruit juice etc also possible.
>>Due to Folding design it can be easily transport.
>>Smaller version with 1 mtr Dia can cook for family of 10.

Disadvantage:
>> Due to higher temperature the burning of food can be possible.
>> loss of food value compare to box cooker and panel cooker is higher in this type.
>> Attention is must for tracking and to check for over burning,


Different types of Concentrating Cookers Available in market:
As per the constructional point of view there are lots of concentrating solar cookers are available in market.
SK-10 = parabolic circular cooker with dish dia 1.0 mtr
SK-14 = parabolic circular cooker with dish dia 1.4 mtr
SK-23 = parabolic circular cooker with dish dia 2.3 mtr
Prince 15 = parabolic square with area 1.5 sq mtr
Prince 40 = parabolic square with area 4.0 sq mtr
Butterfly = Butterfly type design with total area varies from 2 sq mtr to 5 sq mtr.

Also as per the size there are big community solar cookers are available in market in next post we will discuss about all above along with complete technical details.

Devang Joshi
Rudra Solar Energy