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OT: Propane question

redneck6497
redneck6497 Posts: 180
edited November -1 in EggHead Forum
Hi All,

I was cooking last night, and using my propane powered heater. I noticed that the flames were getting low. I jiggled the propane tank a little, and they kinda came back up a little. Then, I noticed there was a good bit of frost on the whole tank (not anywhere near cold enough for frost). The tank seemed pretty light compared to the new one I brought out. I hooked the new one up, and it seemed to be normal again. I thought the propane tank was relatively full.

Where did the frost come from??

Comments

  • FlaPoolman
    FlaPoolman Posts: 11,676
    Been a while since I did gas work and forget the temps but you could tell the level of gas left in the tank by feeling for the temp difference on the tank. The lp is much colder than the steel tank.
  • Fidel
    Fidel Posts: 10,172
    As the liquid inside the tank decreases (as it empties) the gases expand and temperature decreases as well - so the air and liquid inside the tank get colder than ambient temperatures. The humidity in the air condenses onto the tank and will freeze in some cases, like you've witnessed. Compounding the issue is that the propane converts from liquid to gas by absorbing heat from its surrounding environment.

    Look up the Joule-Thompson effect for a more thorough explanation.
  • Wow... Dr Fidel!
    I've seen that happen too, actually on the little bottles when I used them on a coleman campstove while out in the woods, they collect frost on those no matter how hot or how long you run the stove.

    Thanks for the explanation!
  • RRP
    RRP Posts: 25,880
    back in my gasser days I had plastic strips that were glued vertically to my tanks. They were temperature affected and changed color so at a quick glance you could see how low they were without needing to lift them. Very handy and cheap as I recall.
    Re-gasketing America one yard at a time.