[!bob]

as the title says i was watching a review on the valken proton and it frosted over i was wondering why that would happen. i thought that was the point of hpa.

[HeroForADay]

Thermodynamics - and as far as I know when a gas is placed under a high amount of pressure, a significant drop in temperature will occur when that pressure is released.

The quicker you compress a gas - more heat is created. The faster you decompress it - a more significant drop in temperature.

This post has been edited by HeroForADay: 28 January 2013 - 01:45 PM

[andrewthewookie]

It doesn't even have to come from a compressed state (or what we think of as compressed, since ambient pressure at sea level is being compressed by the weight of the atmosphere), as long as the pressure of the gas is reduced quickly enough, significant cooling occurs.

This post has been edited by andrewthewookie: 28 January 2013 - 03:49 PM

[mr.satire]

Its due to energy transfer, compressed gas, contains more energy than a gas at a lower pressure, so it transfers that energy to the lower pressure gas when the pressures equalize, and thus since the high pressure gas is loosing energy it gets cold

[!bob]

so what helps prevent this? more volume in a gun to help the transition from the tank to the atmosphere?

[Danny D]

It's usually a non issue. If you want to prevent it from happening, limit your rof and don't shoot the whole tank at once.

[Pakistani]

!bob, on 28 January 2013 - 11:40 PM, said:

so what helps prevent this? more volume in a gun to help the transition from the tank to the atmosphere?

in pretty much any real world scenario, you'll never have to worry about it. Unless you plan on shooting an entire case straight through from the back center, then it won't happen to you. If it does, then it wont affect anything.

[HeroForADay]

Yep, the only real way to have this not happen is to slow the rate of decompression. So in a real world scenario, you shoot slower, and you have less reduction in temperature. It's the same principle that people sometimes criticize Bob Long for in his early G6R efficiency videos.