System Construction

Solar Concentrating Disc (Primary Reflector) – Part A

The Community Solar Cooker (Rotating Disc Type) works on the principle of solar energy concentration using a Reflecting Parabolic Solar Concentrator. A 7-squaremeter area parabolic solar concentrator is used for concentrating solar radiation on a focal area where the cooking vessel (Part D) is placed.

Automatic Tracking System – Part B

With the help of a simple automatic mechanical tracking system the solar disc rotates in the direction of the movement of the Sun to give continuous and accurate solar energy concentration. This mechanical device is made up of a simple clock mechanism with chain & gear arrangement to provide regulated tracking motion to follow the path of the sun through out the day – from dawn to dusk and gives daily about 6 – 8 hours of operation time.
 

Secondary Reflector – Part C

This is provided opening in the north-facing wall of the kitchen or the cooking place just below the cooking vessel. This reflector receives the concentrated solar radiation and reflects it on to the bottom of the cooking vessel as shown in the figure above.

Installation and Working of a Community Solar Cooker

The Solar Cooker is installed in the open shadow-free area or on terrace tops facing the South. The reflection of the disc falls on a secondary reflector housed in an opening in the North kitchen wall. The secondary reflector further reflects the radiation on to the cooking vessel place above in the kitchen. See photograph.

Simple Operation Method

The Solar Disc is installed in an open area - terrace or courtyard, facing the South. The cooking place and vessels faces the North (at the same ground level).

The cooker is very simple to operate and easy to maintain.

Daily in the morning the disc is manually oriented so as to face the morning sun – in the east. The daily orientation action winds the clock mechanism to work throughout the day and the disc starts rotating in the direction of the Sun guided by the Sundial. The Cooker begins to work automatically as the concentrated solar energy is directed to the cooking vessel. The primary concentrated reflection falls on the secondary reflector, which is placed right below the cooking vessel. The secondary reflector diverts the solar energy on the cooking vessel and the heating begin.

The seasonal orientation (adjustment) of the disc is required to be done once in six months due to shift of the Sun’s position, with respect to the Earth axis, i.e. when the Sun changes its angle at the summer and winter solstice on 14th January each year.

Other Applications of the Rotating Disc Solar Concentrator

This system besides the cooking function – twice a day, can be utilized for water heating during the non-use period. The hot water can be used for cleaning cooking and other utensils. This will increase its utility.

These Solar Concentrators can also be used for industrial applications for heating water or other liquids.

This device is an ideal renewable energy application for saving conventional energy costs in community kitchens to a great extent. Kitchens operated by ashrams, educational institutions, hostels, hospitals, religious places, etc. can effectively utilized the Community Solar Cooker.