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9 months agoThis is the right answer. As LP gas converts from a liquid to a gas in the tank the latent heat of vaporization is provided by cooling the bulk of the liquid. Eventually, the liquid becomes so cold that it will not evaporate, it will not become a gas. You cannot use more of it until there is enough heat input to evaporate the fuel. This can happen in warmer weather when the withdrawal rate is too great, so that even then, you have to provide supplemental energy, heat, to allow the liquid to vaporize. LP gas, commonly “propane” but typically a blend of propane and butane, is difficult to use in cold weather for exactly this reason.
That reference is garbage. The temperature at which a liquid becomes a gas is the boiling point. At atmospheric pressure the boiling point of propane is -44F. According to the textbook Organic Chemistry by Joseph M. Hornback, propane has a boiling point of -44° F (-42° C) at atmospheric pressure. 20F is is a problem because it is getting closer to the boiling point at atmospheric pressure so that more external energy is required than can move from the exterior of the tank to the interior to prevent bulk cooling to the the point where the tank can’t make pressure greater than atmospheric pressure.