Venting propane will cool the C3

only thing is that you need a proper propane to oxygen ratio to get good ignition. flooding the combustion chamber with propane would cool it down but it would also cause the mixture to be too rich. plus you gotta look at it like this. combusting propane only creates a certain ammount of pressure, that cant be increased withought adding another oxidizer in order to add more propane (to keep the combustion ratio proper) so if they are using all the pressure from the the explosion to simply fire the paintball, you'd have a hard time using it to also cock the gun. if you were to use a compressed bottle of nitroud oxide or pure oxygen lol (please dont try this) you could probly generate enough pressure.. thats how i understand it anyways. please correct me if i'm wrong..

semi auto i think is possible and the heat problem could be adressed with a gripframe made with a material that didn't conduct heat well.. the body would be hot but just dont kiss ur gun after laying down some heavy fire lol. i think that full auto would be hard tho or any high rate of fire for that matter cause u have to keep venting the gas after each time you shoot. i think if you added some sort of electrical componant to it. to suck and vent air quickly.. i dunno it would get complicated.. worth looking into tho. would be cool

FYI: Propane becomes a liquid at about 140 psi depending on temperature too of course. When a tank is marked with ounces it means it's measured for liquid. The tanks are filled with about 80% liquid for safety reasons. That sure seems like a lot of liquid to me. I will partially agree with what you said about the lower pressure of propane, which when you compare it to something like CO2 it's a big difference. The more pressure you have the more energy it takes to create the pressure, therefore generating more heat/friction. With that being said you also have more potential energy from the higher pressure and thus more cold is created once it's released. Every winter several of my above ground pipes become covered with inches of ice because of the higher winter pressures. In the summer when the upstream pressure is only about 300psi, the same pipe gets very cold. EG: Winter=550psi dropping to 180psi/Summer=300psi cut to 180psi. Our natural gas is NOT liquid but seems to REFRIGERATE just fine. What gives?

I'm not claiming to be an expert but I do work with natural gas every day at work, and am very familiar with the properties of gases. I'm a gas measurement technician for a natural gas pipeline company, meaning I work on the electronic equipment that measure the temperature, differential, and pressure to calculate flow rates. Enough about my credentials though.

That being said I am not an HVAC guy, but I do know refrigeration is about expanding gas and compressing gas. Compression makes heat by friction. Expansion makes cold. I don't care what pressure you start with, if you release a pressurized gas to a lower pressure environment you get a temperature drop/cooling effect. Maybe not ice cold but colder than a hot C3.

I appreciate your reply, trust me i do, but I don't think your criticism is very constructive. Everything you said makes me think your the one that doesn't understand refrigeration. I would like to know how liquid has anything to do with this.

For anyone that thinks that 140psi is not high pressure, try cracking a valve open on a tank at that pressure. Trust me, you won't believe your ears.

Edited by getnbizzy - 27 September 2007 at 10:03pm

tallen702 wrote: It was a smart idea, but the laws of physics can't really be changed.

Unless...

oh startrek how i love thee..

You'd have to find some way to keep people from touching the heat-sink as, like any other heat-sink, it gets just as hot as the part it is cooling, it just radiates the heat more efficiently. Now, think about this. If you could get, say, a closed circuit alcohol evaporation system going on that ran through the heat-sink, you might have something, but then again, you're getting really complex and far more expensive than it's worth. Alcohol, btw, is a GREAT coolant. It evaporates at a low temperature making it ideal for keeping things cool. It also condenses at a reasonably high temperature due to it's volatility, which makes it idea for closed-circuit cooling systems. Nothing new, the old browning A-3 machine-guns from WWI used an alcohol cooling system.