I'm baffled by this whole Crisco/shortening candle-in-contraptions meme circulating around. You've got folks shoving these things in everything from copper pots to elaborate sand enclosures, claiming superior heat output and somehow making a case for off-grid energy.
Let's unpack the physics, because frankly, it doesn't add up:
Combustion 101: A candle (or our Crisco-fied iteration) works by burning the fuel source (fat in this case), releasing heat and light through a chemical reaction with oxygen. The material surrounding it doesn't inherently influence this combustion process. Copper, terracotta, or sand won't magically accelerate the burning rate or somehow trap more heat.
Radiation & Conduction: Sure, these materials might hold and radiate a BIT more heat absorbed from the flame compared to open air. But the difference is negligible. Convection (hot air rising) is the primary heat transfer mechanism, and the enclosure doesn't significantly enhance it.
Scaling Up Fallacy: If this contraption truly held the key to efficient off-grid heating, wouldn't we be ditching fuel oil and natural gas entirely? Imagine a skyscraper-sized Crisco candle in a cosmic copper pot - it wouldn't magically solve our energy needs. The heat output wouldn't scale proportionally due to limitations in combustion itself.
In short -- why are people so fascinated with this? A simple test will show that it is not more effective than a simple candle, yet people seem to be continually fascinated by it.
It’s not that there is superior heat output, it’s that there is superior heat collection and observation.
Not familiar with the meme directly, taking your attached picture example I can guess why they think it’s better:
It’s trapped closer to them.
Heat, that you recognize exists but usually rises out of reach of an uncapped candle, to the ceiling, is now trapped near the observation area. The pot is trapping it and radiating it much closer to the person thinking they’ve just solved the universe.
It’s observable. Like people who don’t understand the need for vaccines because they’ve never personally seen the disease the vaccine helped beat down, a majority of people struggle to grasp theory, and direct observation is all they understand.
Yeah. The effects of convection from an uncapped candle will spread the heat to the room and ceiling much faster than when trapped. The pot absorbing the heat traps it and changes the heat transfer to radiative heating which will csuse a lower convective heat transfer coefficient when heating the air around it.