Know About Solar Power

Prof. Ghai’s (Anon. 1970) parabolic concentrator was of a different type (PRS2, Figure 6). Evolved in the 1950s, the reflector was made from spun Aluminium sheet. It had a hole at the centre through which projected an arm of the stand to hold the cooking vessel. Part of the reflector was cut out to enable easy access to the vessel. The entire unit had to be turned to face the sun.

These types of cookers did not become very popular, but The German News, 38 (June-July): 5-6, 1997, informs that 180 sq. m, parabolic concentrators have been installed at an institute at Mount Abu, to generate 600 kg. of steam at 16 bar pressure and cook food for 1200 people (Herms 1977).

Fig 3a. Parabolic Mirror array form Mt. Abu ( Source SCI site )

Recently Sintex Plastics of India seems to have entered the Solar Market in a big way. They had been manufacturing Solar Water Heaters of Plastic, but now they are trying their hand at Solar Cookers, the Parabolic as well as Box type Cookers. I am yet to receive the samples for evaluation. The photo presented here has been copied from their site, though it does not display any innovations, the price is very competitive at just Rs. 2500. Of course, much depends on the reflective coating too, and again I am yet to receive details regarding the same. With a long lasting Reflective material, and at the price, this Parabolic Cooker should steel the market.

Another recent addition to the family of Parabolic cooker comes from the prolific inventor Mr Deris of California. The Parabola it self is simple, he seems to have discarded the interesting design of square Parabola invented by himself. The parabola he uses is held vertically, and it directs the focused rays on to a Cooking vessel kept on a reflector kept horizontally on the ground.

Interestingly way back in 1980, I had proposed that a reflector/focusing device kept outside or in a suitable position would point focus the image in the house which could then be used for cooking. This design you would see under Type ---but such a concept has already taken shape, independently at Bahai institute in India and with the help of a parabolic reflector kept out side the hut cooking even Chapathis are being cooked.

Fig 3a1 & 2 Photos from Bahai Institute, India ( Ref. their site on the web )

The following diagram shows the principle of Scheffler's reflective cooker design in detail.

The photos bellow shows Scheffler's reflective cooker, a 2.7 m dia cooker, just out side an Indian Home, The photos are from ecosolar.com. The second photo shows a lady cooking in a small kitchen.

The parabolic cookers are being uses in Africa as well and the photo below confirms it further.