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Energy Conservation in Cooking

PostPosted:Thu Jul 27, 2006 7:53 pm
by krishan arora
An extremely high proportion of fuel energy is wasted, in conventional cooking practices, as heat lost to the surrounding air, even if we are using the relatively energy efficient pressure cookers. This heat loss may be as high as about 80% for soft foods, like rice etc, to as high as about 95%, or even more in the case of open vessel cooking, for the harder foods like black gram etc. This can be readily understood from the fact that once the temperature in the cooking vessel has reached boiling point there should ideally not be any further need for fuel consumption if the heat losses are not taking place. In actual practice however it is seen that fuel consumption continues for long after boiling point has been reached, in order to compensate for the heat loses and thus to maintain the food at boiling point till the cooking is complete.

This is also borne out mathematically by considering the calorific values of the fuel used and the theoretical times required for cooking, in the absence of heat losses, and comparing these with the cooking times actually needed with conventional cooking practices. We can then readily imagine the extremely high fuel savings that can therefore be achieved just by eliminating the heat losses using the thermal insulation methods.

Most of these heat losses can be avoided if we were to use thermally insulated cooking vessels, by switching off the fuel as soon as boiling point has been reached and then allowing the food to remain inside the closed insulated vessel for the time required for the food to be cooked with the heat already built up inside. If insulated vessels are not available, then, in the case of small vessels these could be transferred into insulated boxes once boiling point has been reached, while in the case of large vessels, particularly those used in commercial establishments, even just the use of insulated lids would often suffice to retard the heat losses sufficiently to allow cooking to be completed in due time, particularly for the softer foods, without further fuel consumption once boiling point has been reached.

Cooking consumes a very large part of the total domestic energy use, particularly in the lesser developed countries, and the cumulative heat savings on a global scale would be significantly large enough to not only reduce our dependence on fossil fuels but could also retard global warming to some extent because of the reduced total heat emissions into the atmosphere. May I add that energy saved is as good as energy generated, and cheaper!

A cheap and practical option would perhaps be to use brushable/ sprayable insulation coatings on the vessels; and such coatings appear to be already available in the market in the USA and in use for various other purposes, as seen from various advertisements.

There are many other significant benefits too with this method, particular on the health and environmental sides, and these can be discussed separately.

Reward: Rapid, worldwide adoption of the method would be reward enough for me. I would of course like to know the details of the coatings adopted and a sample cooker for further trials.