Solar Parabolic Cooker is an umbrella like structure that reflects hest energy from sun to an object. The reflected heat energy is used to cook food material. The sun rays are made to reflect on a parabolic surface and concentrated on a focal point on which the cooking pot is placed. The reflector is made up of thin aluminum sheets coated with mercury and is supported by metallic frame. The reflector can be easily adjusted according to sun orientation. The temperature obtained is very high but the loss due to convection and conduction is also considerable. In any solar cooker the time of cooking is inversely proportional to reflector area.

The cooking time and temperature in a solar cooker depends upon:

• The ambient temperature is more in the summer than in the winter. Hence, cooking is faster in summer.
• Time of day (11.00 – 14.00 hours is the best time)
• Type of food ( soft or hard)
• Depth (thickness) of food layer. Thin layer of food is cooked faster. Maximum thickness of the food layer should be 6 cm.
• Cooking utensils of thin metal with tight lids, painted dull black outside, cook faster.

Technical Specification

• Name : SK-14
• Size : 1.4m (Diameter)
• Shape : Parabolic
• Weight : Iron Frame (25 kg)

                : Reflector Sheet (3.6 kg)

• Reflector Sheet : Aluminum
• Output Obtained : 600 watt
• Efficiency : 50% (Related to direct solar radiation)
• Expected to last for 5 – 10 years.

Advantages

The following advantages can be achieved by the user of the solar cooker:

• Simple and proven technologies; no training is needed to operate it.
• Saves energy and money by reducing the use of kerosene, LPG, oil, etc.
• Solar Cooker retains nutrition and cooked food has natural taste.
• Smoke-free, environmental friendly design and saves time.
• No repair & maintenance cost required.
• Easy to manufacture, simple to use and portable.

Durability

Solar Cookers require almost no maintenance, except that for optimum performance, the glazing surface should be kept clean. If properly cared for, the solar cookers can be expected to last for 5 – 10 years.

Potential

The average solar energy potential of Nepal amounts to around 700 – 800 watts/sqm or 6 kWh/day with 8 hours of sunshine. Promotion of the solar cooking/heating technology for poor people in the rural areas at low cost may partly solve their cooking problem.

Efficiency

A properly designed solar cooker can cook daytime meals for a family of 5 for4 about 250 days a year. Utilizing the rays of sun falling on 1 sqm area for a whole day, 50 liters of water at 20 deg. C can be boiled.