[bch]

There used to be (still is?) a sort of vertical chute/collar available to put around camp pots. Think mountaineering applications. The idea was that they would capture heat energy escaping off the bottom of the pot that would rise/disperse into the environment, and channel it close to the side of the pot where it would heat the vessel as it rose. Think of wrapping a section of corrugated cardboard around the outside wall of a pot. Now a birds-eye view down the cardboard should reveal the energy capturing channels that will allow the sides of your pot to heat the pot contents. Adjust your material and tune the sizing and you’ve got a camping gadget.

[amluto]

This is maybe useful for boiling water but not so great for cooking. You want your pot to have a relatively uniform temperature, and gas burns very hot. This means that, especially if the walls of the pan are thin, any part of the wall that has good thermal contact with combustion products and poor contact with food will get extremely hot, with various unfortunate consequences. Also the handles will get hot.

[nerdponx]

Well it takes absolutely forever to boil water on a camp stove, so I"ll take it.

[chipsa]

Look into jetboil campstove/pot. It's got a heat exchanger fin stack on the bottom of the pot to improve boil time.

[thebiss]

Typically, those collars are used as a wind screen.

https://www.rei.com/product/139472/toaks-titanium-windscreen

[bch]

No - found a reference:

https://www.msrgear.com/stoves/stove-accessories/heat-exchan...