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redarrow7216 t1_j4nch76 wrote

Reply to comment by festerwl in I have a ventless propane fireplace insert that had a 100 gallon tank outside. Can I replace it with a refillable 10 gallon tank? by KevinAnniPadda

Wait what? The volume does not matter for pressure. For propane/butane tanks only the temperature is of importance as they liquefy on lower temperatures and the pressure decreases. Also pressure drop in tubing/piping is neglible in low flow short run conditions. Smaller tanks do run empty quicker though.

https://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

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festerwl t1_j4neh8z wrote

The larger tanks have the ability to hold temperature better. If the heater is using a large amount of propane the smaller tanks can ice up quicker than the larger tanks.

And yes the pressure drop isn't noticeable in short runs but some use 1/2" black pipe like natural gas and a grill size tank will have a hard time if you're out like 20ft.

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redarrow7216 t1_j4rgdzz wrote

An average 3-4kW chimney uses only about 500L of gas per hour. That are really low volumes, even for 1/2" pipe.

Joule Thompson effects are measurable over an orifice i.e. Regulator but not really in these cyllinders. Also with these low pressures 1-2bar JT effect would be +-1 degree Celsius for pressure drop to atmosphere entering the chimney. Yes, the tank can hold more heat as more fluid is present but will still quickly cool down/warm up with the ambient temperature.

I dont think OP has any benefit with a bigger tank looking at his consumption or other circumstances.

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West-Advertising-545 t1_j4ne271 wrote

There’s a difference. It will be listed as a minimum tank size in the manual for proper performance.

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