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A blacksmith’s good heat and bad heat

An engineer friend visited a working blacksmith on a museum and asked him about the metallurgy and heating processes. The blacksmith pointed out that coke is the best fuel for getting a good hot furnace and that a gas-fired furnace, while able to get up to the same temperature does not produce as “good” heat as coke.

Now, this sounds almost silly…doesn’t it? Heat is heat – vibration of atoms in a substance and temperature is the measure of that rate of vibration. How can some forms of heat be better than others? Well, my friend, his curiosity piqued, wonders whether processes analogous to fluorescence might occur in with infra-red. Perhaps, he suggests, as with a bright light shone on a fluorescent watch face or child’s decorative wall stars and planets, the materials store up some of the radiant energy from the burning coke and release it as fluorescent heat. The temperature would be the same, “red hot” but there would be more energy available. Is this what the blacksmith means by good and bad heat? There would be none of the potential for such a fluorescence process if the furnace is being heated directly with burning gas.

It reminds me of a concept chemical engineers use when they want to lower the temperature of a system, such as a distillation tower: they add “coolth”…the opposite of warmth, negative heat, uncoolth. It’s a concept that works for their “back-of-an-envelope”, “rule-of-thumb” calculations to set up vast quantities of refluxing liquids and reagents optimally. Is the blacksmith’s good and bad heat nothing more than a coolth-like fudge, or is my engineer friend on to something?

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