Join Date: Feb 2000
Location: Annapolis, Md
Thanked 82 Times in 63 Posts
Rep Power: 10
Quote from Eherlihy
"I always thought that (in general) you would get a higher BTU rating from a propane stove than an alcohol stove. I imagine that with more surface area per burner, an alcohol stove will have a higher BTU rating, but Propane is still a hotter flame."
If an alcohol burner has a higher BTU output that burner is putting out more heat per unit of time, which is what effects the rate that a pot heats up.
But I want to comment on the quote above. While it is a true that a theoretical flame temperature of propane flame is hotter, the difference is tiny. In real life applications it is not necessarily the case. The heat of the flame is determined by the design of the burner and access to oxygen. With a proper blemd of oyxgen propane burns at temperature that is only 1% higher than Alcohol. (see table below) The brilliance of a catalized alcohol stove (like a Origo) is its high efficiency in getting heat out of alcohol while marine propane burners are not especially high efficiency.
In making the statement, I suspect that like many people Eherlihy is mistaking the heat capacity of propane per pound (propane produces nearly than twice heat per pound of alcohol or 10% more than diesel fuel) for the heat of the flame.
|Fuel||Flame Temperatures (in degrees Kelvin)|
| ||Constant cp (value at 298 K)||Variable cp||CET89|
|i-C8H18 iso-octane (the main component of gasoline)||2895||2411||2275|