Dish Type Solar Cooker
Dish solar cooker is used for faster outdoor cooking for about 10-15 persons with solar energy. A dish cooker usually with a dish diameter of 1.4 meter is made of single reflector or by joining smaller pieces of reflector, fixed to a rigid frame, when exposed to Sun in the normal direction; a point focus would be formed for cooking food. It consists of bright anodized aluminum sheets of 0.4 mm thick or 3 mm thick glass mirrors, bowl supporting frame, bowl stand, and manual tracking mechanism. Accessories like cap, hand gloves, goggles, manual and 5 ltr capacity ISI marked pressure cooker are also supplied with dish cooker. This cooker may be used for cooking food without any conventional fuel for large families or institutions where food is cooked for 10-15 persons everyday.
Specifications of DishType Solar Cookers:
Configuration – Parabolic dish, made of single reflector, or by joining smaller pieces of reflector, fixed firmly to a rigid frame. Size and shape of the dish shall be such that when exposed to sun in the normal direction, a point focus would be formed.
Dish diameter – 1.4m, minimum
Reflector material – Bright, anodized aluminium sheets of thickness 0.4mm or glass mirrors, thickness about 3mm, with suitable protective layer on back to minimize degradation of the reflective coating due to weathering.
Reflectivity – >80%, minimum
Useful life – 5 years, minimum
Focal point – When dish is exposed to sun’s rays at normal incidence, the size of the point where reflected rays get focused would be less or equal to the size of base area of the cooking pot.
Supporting frame of the dish –
Made either of MS rings supported by MS strips, FRP material, or thick MS wire – mesh structures
Rigid enough to resist any deformation of the dish shape due to wind pressure or manual handling
The MS structure will have epoxy/anti – rust coating
Stand for the dish –
Made of MS with epoxy/powder coating
Equipped with an arrangement to hold cooking pot of different sizes
Having a suitable provision to secure the cooker to the ground
Tracking mechanism –
Manual or automatic, allowing unrestricted rotation of the dish along its horizontal and vertical axes enabling its adjustment in the normal direction to the sun’s rays
Provision of locking arrangement to hold/fix the dish at a desired position
Equipped with an arrangement to enable users to position the dish in a direction normal to the sun’s rays
Cooking vessels –
For dish of about 1.4m dia, a pressure cooker of 5 1 capacity is usually being provided.
For other sizes, proportionately higher capacity of pressure cooker is to provided.
High temperature resistant black powder coating at the bottom to be provided.
This Cooker can cook as fast as a conventional electric burner and even can fry foods
Box Type Solar Cooker
Box type solar cooker consists of box and a reflector fitted lid. Cooking utensils are placed in closed insulated enclosure where they get heated up to 80 ° C which is enough for proper cooking. Due to gradual cooking process, essential vitamins are retained and the food is not damaged which might be the case due to excessive heating.
Scheffler Cooker (Community Type)
This is a solar concentrating parabolic cooker consisting 7 m2 Scheffler concentrating dish. The schefler dish acts a primary reflector. The secondary reflector is flat surface located inside the kitchen on which the cooking utensil is placed. The concentrating action of the scheffler dish achieved the temperature between 450 to 600’C within the comfort of the kitchen. The system can be used to cook a wide variety of food, including Chapatis and traditional preparation that required roasting or frying. Cooking is possible in the kitchen and useful for 4-50 peoples cooking. There is not need to stand in the heat of the sun during the cooking. Once it is set in the morning, tracks the sun automatically.