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Energy Saver: Cooking Techniques
(continued ...) temperature to simmer in the flavors for about ten (10) minutes. Dinner is ready! Sound familiar? Okay, I'm no chef.
Running those two heating elements for twenty-five (25) minutes each to make dinner will create about 7,000 to 9,000 Btu of heat energy. Did you make a more complex meal and it took an hour to make dinner? Then the total would be 17,000 to 22,000 Btu per hour. Either way, a large portion of that energy wasn't used for the desired output of making a meal.
How much heat energy was actually used productively for the cooking task? A lot of variables can play a role in getting that heat energy transferred to the water. Before I get off onto a tangent again, let's jump over the minutia and round off the numbers. Let's say you have two (2) quarts of water in your pot on the element. We want to go from tap temperature to boiling. The temperature increase would be about 150 degrees rise. That requires roughly 600 Btu. Once upon the 212 F (100 C) threshold, the temperature of the water stops rising and then the energy goes into phase change to water vapor (steam) but the rest is lost. The other burner is doing about the same thing in browning the burger for another 600 Btu. But you said the burners created about 8,000 Btu to get to boil and simmer. What gives?
Exactly; something on the order of 7,000 Btu was wasted energy! Where did the wasted energy go? You heated the pot, the stove, the adjacent air, converted water liquid-to-vapor and a dozen other losses. Among other examples, this is what I call 'junk' heat energy that went into the surroundings in your kitchen ...