An engineer friend visited a working blacksmith on a museum site 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” a type of 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 with infrared. 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 adding warmth. Negative heat, uncoolth (see also: the deceived wisdom of negative pressure). The coolth concept works for the chemical engineers’ “back-of-an-envelope”, “rule-of-thumb” calculations so that they can set up vast quantities of refluxing liquids and reagents optimally at the right temperature, add a bit of coolth to bring it down to the right temperature, that sort of thing.
Is the blacksmith’s good and bad heat nothing more than a coolth-like fudge to explain what happens in practice or is my engineer friend on to something with his IR fluorescence idea?
UPDATE: Coolth is a term used to describe the cooling potential or cooling capacity of a substance or a system. It refers to the amount of cooling effect that can be achieved or the magnitude of heat that can be removed from a system to achieve a lower temperature. Coolth is the counterpart of warmth, which refers to the heating potential or heat capacity of a substance or system. Both coolth and warmth are important concepts in thermodynamics and heat transfer, and they are often used in discussions related to refrigeration, air conditioning, and thermal management systems.