Originally Posted by
Western Flyer
I have to disagree; I am neither a chemist nor an engineer.
Say wha...?
Originally Posted by
Western Flyer
Not so, you could burn the lower heat content fuel twice as fast and transfer heat at the same rate as the more heat dense fuel. I offered a cat-can stove I built that boiled a half liter of water in the same time as an Optimus canister fuel burner. Perhaps you didn’t see my entry and pictures.
You can't burn a lower heat content fuel at twice the rate
and transfer heat faster by just making the pool of fuel larger. First, the fuel has a specific amount of heat per mass. If it has less heat per mass, you have to burn more of it to transfer that heat. If you make a large pool of it, you just lose more of the heat to the surroundings. You also have mass transport problems with larger pools of fuel. The yellow flame of your picture and the sooted bottom of the pot indicate that you aren't burning the fuel efficiently because the fuel isn't getting enough oxygen.
There are natural laws that you simply can't violate which dictate how much heat a substance has and how fast that heat can be delivered. You can't break them or even bend them. You may think you have bent them but you really haven't. You are likely comparing caulk to cheese by doing a poorly controlled experiment. You can compare the fuels and the heating rates but you need to use equipment that is the same or at least similar enough to give you a meaningful comparison.
Originally Posted by
Western Flyer
I am sure this is true, all things being equal, but it is my understanding that plutonium is a very energy dense fuel but it boils water very inefficiently. That is the closer the temperature of the heat source is to the desired temperature of the substance being heated the more efficient the heat transfer. Quite frankly I have no idea if the energy transfer potential between ethanol burning Trangia and say a kerosene burning Wisperlite International is enough to put a period between.
Let's not wander off into silly territory. Sticking to the point of liquid fuels used for camp stoves, there is definitely a difference in the energy transfer between ethanol and kerosene and the equipment used to burn the fuel. For example, kerosene used in a Trangia would provide more heat than ethanol because it has a higher amount of energy to give up. In an open burn situation, however, the amount of oxygen getting to the fuel would be limited and it would burn cool. It would produce lots of unburned carbon which is an indication energy loss. Pressurize it, atomize the fuel and efficiently mix it with oxygen and you can capture nearly all of the energy the fuel has to offer.
On the other hand, if you were to do the same with ethanol, i.e. pressurize it, atomize it and efficiently mix it with oxygen, you would see a gain in capturing energy but there isn't as much to gain as hydrocarbon fuels. Your fuel is partially oxidized and therefore doesn't has as much energy to give up.
Originally Posted by
Western Flyer
But this is precisely the beauty of alcohol it is so readily available that in theory you might not have to carry any fuel at all. You just need to buy enough at the end of the day for dinner and breakfast. That’s assuming you don’t stop for high tea in the afternoon.
This leads to one of the prime reason I prefer ethanol as a stove fuel. It's a biofuel and renewable. I know biofuels are in their infancy and it is supposed to take one barrel of oil to produce 1.25 barrel equivalence of corn based ethanol energy. I can live with that with the fuel economy I get on my bicycle. I read MIT has developed a
biopropane and someday I may buy a green Pocket Rocket stove when one comes on the market.
:
I hate to break this to you, but most of the alcohol fuels you are likely to use, outside of something like Everclear, are produced from petroleum. Drinking ethanol is made by biological processes and has been for millennia. But commercially produced ethanol that is use in denatured ethanol is made through refining and cracking and treating oil.