# Closed loop gas system for cooling

I'm having issues when setting up a "closed (infinite) loop gas pipe" in Oxygen Not Included. Does anyone have a set of reliable instructions for building such a system within the game? (to be used for cooling).

Start with a long a long pipe with a pump at the input and a gas vent at the output. Pump a bunch of gas through it, then connect the output pipe to the input pipe and disconnect the pump and the vent. And voila, you have gas which circles infinitely through the pipe without needing to spend any energy pumping it.

Except... not quite. Sometimes you wind up with each gas "packet" getting briefly stuck somewhere, such that every packet is only moving every other tick instead of every tick. Sometimes some of your gas packets decide to stop and turn around - in general, the gas is still flowing in a circle, but there are back ups which slow the whole thing to a crawl.

There are lots of tutorials on how to set up the infinite toilet/water seive loop, but none that I could find on this kind of gas loop. But I've seen it, so I'm pretty sure it can be made to work.

Anyone know how to do this consistently? Or, can anyone confirm that there's a mechanic (e.g. friction inside pipes) that would prevent this perpetual motion machine from working long term?

• @Stese this is bad advice. Please do not post this question on Superuser. Rant aside, I would assume the reason it sometimes work is the exact amount of gas in the pipes. I'd try with fuller/emptier pipes and see if it works out better. Commented Jan 10, 2018 at 14:25
• Also, it might have something to do with bouyancy, see if it works better to have to cold parts below the hot parts. In reality, warmer gas will end up on top of the colder gas, maybe they have coded this into the gas physics. Commented Jan 10, 2018 at 14:32
• For those confused, Oxygen Not Included has a robust gas and liquid simulation system that the game is built around. Commented Jan 10, 2018 at 15:00
• The amount of gas definitely has an impact, but the exact timing of when you disconnect the pump and/or vent seems to affect it too. Once I get my automation (logic circuits) upgrades up and running I'll play with a few methods that are better controlled / timed and see if I can find something repeatable. P.S. @DJ Pirtu I'm not sure a "robust" simulation is accurate when making a perpetual motion machine is possible ;) Commented Jan 10, 2018 at 15:30
• @Stese Imaginary "tone" issues aside, if you're going to take it upon yourself to tell people their question doesn't belong here, you should make sure you actually know what the question is about first. Commented Jan 11, 2018 at 8:23

Liquids and gasses in pipes work the same, so the tutorials involving loops apply just the same. In order to have a good loop you need to tell the loop which direction to take via pipe bridges.

I'd suggest deconstructing two sections of the pipe and build a bridge on one side of the section (the part of the bridge to be built onto the section must be the input).

Wait until all gasses move in next to each other and then build the closing pipe from the bridge output onto the rest of the loop.