LOL! You can't do that. The state of candle wax (solid or liquid) depends on its temperature. Heat it, it melts. Cool it, it solidifies. The atmospheric pressure might play a part--for instance we all know water boils at a lower temperature when the pressure is reduced. I'm not sure if that applies to wax, but even if it does you're also changing the availability of oxygen so that would invalidate your results.
If it's any consolation to you, wax that burns in a candle is always liquid. It has to be liquid to be absorbed into the wick and travel up to the flame! If a wick was simply suspended in a pool of molten wax, it might burn better, because it isn't using some of its heat to melt the wax as it goes, which is how a candle normally works. But there's no way to avoid that that melted wax is hotter than solid wax, because if it wasn't, it would be solid!