Ok, they don't show 100# tank, but extrapolating from 200# looks like it might be a stretch for cooktop that might be pulling 50Kbtu/hr or so with all burners in use.
propane conundrum
- Thread starter RustyShackleford
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100lb tanks have a really small surface area. The tank is tall and thin so there isn’t much surface to evaporate from. A fatter tank will be able to evaporate more.
I'm not sure; a fatter (more resembling a sphere) tank will have less surface area relative to its volume.
The same volume in a cylinder has more surface area.
It’s not the sides that matter. It’s the circle where the liquid propane can evaporate. The top of the liquid. A wider tank has a circle with a larger area. I’m probably not saying this right.
No, it's the heat input that creates evaporation. The boiling does not happen at the surface of the liquid, it happens at the interface between liquid and metal tanks - that's where the heat comes in.
Like water boiling in a kettle or pot: the bubbles get formed at the bottom where the heat input is.
The surface area of the tank determines the heat input from the ambient environment. Bubbles will form at that interface (walls and bottom), and will rise to whatever small "top of the liquid surface" there is.
Same as having a beer bottle on a stove; the boiling will happen regardless of how narrow the neck is where the (small) surface of the liquid is.
It's based on the surface area of the propane tank exposed to the outdoor temperature that allows the liquid propane to absorb heat from the surroundings.
A couple square inches of surface area is all that is needed if the temperature is sufficient to boil the propane.
Keep in mind that chart is for steady state operation. A propane tank that is only used occasionally, say for half an hour a day to run a couple stove burners, can supply the required gas solely by its own internally stored heat.
We use 500k btu propane torches on 20lb bottles all the time, the torch works great for the first 5 or 10 minutes until the entire bottle cools off, then the rate of gas boil off is proportional to the amount of heat the bottle can absorb from its surroundings.
A couple square inches of surface area is all that is needed if the temperature is sufficient to boil the propane.
Keep in mind that chart is for steady state operation. A propane tank that is only used occasionally, say for half an hour a day to run a couple stove burners, can supply the required gas solely by its own internally stored heat.
We use 500k btu propane torches on 20lb bottles all the time, the torch works great for the first 5 or 10 minutes until the entire bottle cools off, then the rate of gas boil off is proportional to the amount of heat the bottle can absorb from its surroundings.
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