Most pots and pans have flat bottoms.
A gas stove uses a flame to heat the pot or pan, but what's really happening there is that hot gases from the flame flow past the bottom of the pot or pan and some of the heat is transferred to the metal.
Now, this metal is often copper already for excellent conduction of the heat to the food. That's not what this is about. Not all of the heat in the gases is transferred to the pot or pan (nor can it be, because they only equalize in temperature at best). But they probably don't even equalize near fully, because that takes time, and the gases flow out of contact with the metal before that can happen.
In computer water cooling, it has been found that turbulent flow in a waterblock is more effective than increased internal surface area.
Therefore, I propose adding concentric rings of protruding metal to the bottom of pots and pans, with some holes in them. Hot gases are impeded in their journey to the outer edge of the bottom surface, and their flow is made turbulent. This should increase the amount of heat they transfer to the pot or pan.-- notexactly, Jan 28 2016 Multi Boiler Tube Kettle Steam-Age_20Kettle [bs0u0155, Jan 28 2016] You mean like this? http://www.jetboil....ccessories/Fry-Pan/Flux ring pan. Also comes in pots. A few other brands starting to make them as well. [Custardguts, Jan 28 2016] You can get kettles like this, with wire cages welded to the bottom-- pocmloc, Jan 28 2016 One bun each for the idea [+] and for [Ian]'s anno.-- pertinax, Jan 28 2016 There's an object named the "simplex quick boil kettle" that has a kind of metal skirt around the bottom with holes, and on the base, I hear stories of some form of coil. I've never seen a real one and the internet doesn't have pictures of the base. But in theory it should be possible to improve the heat transfer. I had the idea of stealing steam engine technology <link> by running multiple tubes through the water, but there must be a simpler way. I like your concentric rings idea. It may be a total pain to clean however, and there will be hell to pay if it scratches the counter top. I think the most subtle, modestly effective but aesthetically acceptable solution would be holes in the base which lead into channels through the base metal and exit pointing upward at the curvy peripheral bit. You'd need a good thickness of base material to get significant upward gradient, but that's a desirable feature anyhow.-- bs0u0155, Jan 28 2016 Unfortunately, the concept of a heat exchanger on the underside of a pan for efficiency when using gas cookers, is well developed in the hiking cookware field. See link.
Case in point the jetboil pots, which are something like 2 or 3 times as efficient in absorbing the heat from the gas flame. They also insulate the pot walls to maximise heat retention. Boils quicker for a given stove heat output, and also/therefore uses less gas overall. Much less heat input required to simmer - although with aluminium or titanium heat exchangers (they call it a flux ring) - you run the danger of burning out the fins if you either a) boil the pot dry or even b) have something stick to the bottom and develop a hot spot.
I'd be very keen to see this technology adapted for home use.-- Custardguts, Jan 28 2016 random, halfbakery