tutorial MiniLOX - A small Oxygen Liquefier in 5 steps

[Sevio]

Edit: Testing has uncovered an unexpected problem where the hydrogen in the system slowly disappears. Unless I can find a way to avoid this from happening or I can work out another compact, simple liquefier which isn't prone to gas loss, I unfortunately can't recommend building this right now. But perhaps the instructions can still aid someone with building their first oxygen liquefier of their own, or inspire them to build an even better liquefier!

Hello everyone and welcome to my Oxygen Liquefier tutorial! In this tutorial I aim to show newer players in 5 straightforward steps how to build the MiniLOX, a compact machine that makes liquid oxygen. You can use this to clean up caves filled with Polluted Oxygen and make it safer to breathe for your duplicants.

I've seen various designs floating around the forums in newer and older threads, there are multiple ways to go about it but one thing they tend to have in common is that they tend to be large and can look pretty intimidating for players who are not used to building and experimenting with large systems. I also haven't seen a step by step building guide for them yet, so here I am with this one.

The oxygen liquefier I will show in this tutorial isn't among the most powerful, nor is it the most power efficient. But it is compact and I've done my best to keep the startup time low so you get to see your first liquid oxygen as soon as possible after building it, without waiting for many cycles for your room to cool down. If you're already familiar with oxygen liquefiers and are looking towards the Aquatuner as your favorite way of making liquid oxygen, this build's minimal startup time also makes it suitable as a temporary setup to make a starting supply of liquid oxygen, allowing you to get the Aquatuner party started.

Here's the MiniLOX in action:

What you will need:

• 12 kg of Hydrogen
• Good supply of Abyssalite (for pipes and tiles that keep the heat out)
• A good amount of battery storage on your main power network  and a Power Transformer (not shown in build)
• A good building location - because this machine will make a fair amount of heat, it's a good idea to build this low in your base, so the heat has a chance to spread out and upwards instead of getting bottled up where the Thermo Regulators are. The area you build it in should also have no CO2.

While following this tutorial, keep these things in mind:

• Where you see insulated Purple tiles, you build normal tiles made of Abyssalite.
• Where you see insulated Yellow pipes, you build normal pipes made of Abyssalite.
• Where you see normal White pipes, you can use standard materials like Sandstone.

So without further ado, here's the 5 steps in which to build the MiniLOX!

Step 1: Building the pump chamber

We will build the pump chamber first as shown below. We also build some pipes and wires on this side of the build as this part of the room will become inaccessible to duplicants in the next step. Make sure your duplicants can access the chamber via the ladder and not from above, as this will be important later.

In the gas overlay, we build abyssalite pipes out from the pump and to the side:

Wiring overview:

Step 2: Building the liquefier

In this step we build the rest of the liquefier room and all the machines and wiring that we'll need. The order doesn't matter, as everything that still needs to be built is accessible to the duplicants from here on.

We add the Thermo Regulators, a thermo switch to control the gas pump, the liquid pump and a hydro switch to control it. We add two vents, one for the hydrogen and one for the polluted oxygen. And we add a gas valve so we can control how much polluted oxygen we let into the room. More on the liquid and wire bridges below.

In the gas overlay we build Abyssalite gas pipes for the Pump and the Thermo Regulators, as well as the polluted oxygen input line with normal materials. The polluted oxygen line doesn't have to come from above, this just happened to be convenient for me in my debug savegame.

In the Liquid overlay we build an Abyssalite pipe out of the room for our liquid oxygen. Also note the two overlapping liquid bridges - they don't have any pipes connected but they will help the hydrogen cool the oxygen much faster. Any material except Abyssalite will do.

Wiring overview - note the wire bridge here on the right side of the room. It's not connected but again, helps the hydrogen cool the oxygen faster.

Step 3: Vacuuming the liquefier

Now that all of the machines are built, it's time to remove the access ladder and close up the room, so we can make it a (near) vacuum. Because the access was in the lower right corner of the room, any CO2 that your duplicants breathed out should have left the room by the time you're ready to close it up. If the area you were in has filled with CO2 since you started building, you should get rid of that first before closing the room. Now that it's closed, set the Atmo Switch to Above 0 g, the Thermo Switch to Above -200 C and the Hydro Switch to Above 50 kg.

Now you can connect the machine to your power line (remember to have a Power Transformer between your main network and the MiniLOX!)

In the gas overlay we build a temporary vent so we can pull out most of the oxygen still in the room. We connect it up with a temporary gas bridge to prevent the gas from going into the thermo regulators. Once the gas bridge is in place, the pump should start pumping all the gas out of the room.

You don't have to wait until the room is completely vacuum - once only a few grams of oxygen per tile is left, it's fine to shut off the pump. You should do this by setting the Atmo Switch to Above 600 g. We also deconstruct the temporary gas bridge and vent. Now the MiniLOX is ready to accept hydrogen!

Step 4: Adding hydrogen

The MiniLOX needs enough hydrogen to circulate through the Thermo Regulators but not so much that the room gets overpressurized too easily once there is liquid oxygen and polluted oxygen inside. We build a gas pipeline to the Gas valve. This will be used later for polluted oxygen, but for now we can also use it to fill the room with just the right amount of hydrogen.

To make sure we add exactly 12 kg of hydrogen, we set the Gas Valve to 0 g/s so it doesn't let any gas through. Then we fill the gas pipeline with hydrogen from electrolyzers. While this is filling up, make sure you have constructed the new gas bridge on the left. This will help combine the hydrogen packets from the pump into larger ones and save you some power on the thermo regulators.

Once 12 pipe tiles have filled up with hydrogen, we can cut off the rest of the pipe, as we have exactly 12 kg of hydrogen now. In this example the gas pipe with the yellow X is the 13th gas pipe and should be deconstructed.

Now we build a gas bridge with the green arrow on top of the end of the pipeline to push the hydrogen towards the Gas Valve and set the Gas Valve to 10000 g/s to allow all the hydrogen in.

Once enough hydrogen has made it in, the MiniLOX should start up and begin cooling the hydrogen to -200 C. Any residual oxygen in the room will end up in the bottom right of the room and get liquefied once it has reached a low enough temperature.

Reminder: Atmo Switch should be set to Above 600 g, the Thermo Switch to Above -200 C and the Hydro Switch to Above 50 kg.

Step 5: Starting up!

Now that it has hydrogen and is cooling down,  The MiniLOX is ready to run! All that's left to do is set your Gas Valve to 50 g/s and connect your gas pipeline to some polluted oxygen. If you gave the room time to cool down to -200 C, you should see your first liquid oxygen start to form very quickly. If it hasn't entirely cooled down yet, it will take a bit longer but the pump will start working faster now that the hydrogen is being pushed into the top half of the room.

If you want it to go faster, you can turn up the gas valve but if you don't have much liquid oxygen yet, adding too much polluted oxygen at once will make it evaporate again, which can sometimes allow too much polluted oxygen to build up inside the room. If that happens, you should shut off the Gas Valve and give the Thermo Regulators to catch up and make everything liquid again.

The MiniLOX will create quite a bit of heat while you're making liquid oxygen. One way to deal with it is to put some wheezeworts nearby, another is to put a liquid vent above your thermo regulators and connect the liquid pipeline to it. This way, the liquid oxygen you're making will cool your thermo regulators and you get your oxygen back into your base at the same time!

And that's it for this tutorial! You now have a working Oxygen Liquefier that fits in a pretty small space. I hope you found my tutorial useful and maybe following it has made you a bit more familiar with how you can use Hydrogen and Thermo Regulators to cool things down and how the different switches and valves can help you precisely control pressure and temperature.

If you'd like to have a look at the savegame I used to make this tutorial, you can check it out below. There's also some radiator based designs I experimented with but those take a longer time to cool down to temperature and need a lot more space.  (Warning, you will need to use debug mode in order to see everything)

The First Law Superchill.sav

[Saturnus]

You technically don't need 3 thermoregulators in series in this design. One with a single step feedback loop is plenty. You see, feedback loops are ideal on thermoregulators as the maximum output of a pump is precisely half the maximum throughput of a thermoregulator, so using feedback loops with thermoregulators actually saves a lot of power without any performance hit.

[Sevio]

That's a possibility and I hadn't thought of that before, however conceptually I think 3 thermo regulators might be easier to understand than a feedback loop and Thermo Regulators aren't too expensive. After some testing the throughput appears to be slightly higher than the theoretical maximum performance of a single thermo regulator (Throughput is just under 200 g/s where a single regulator with maximum uptime could pull about 149 g/s), so going back to one would reduce throughput a bit.

Lastly, because the flow from the pump is intermittent I think a feedback loop would lead to pipe freezing, I had a similar problem with that in my Final Boiler Fantasy V build, which is why I didn't include the feedback loop as standard.

[Saturnus]

41 minutes ago, Sevio said:

That's a possibility and I hadn't thought of that before, however conceptually I think 3 thermo regulators might be easier to understand than a feedback loop and Thermo Regulators aren't too expensive. After some testing the throughput appears to be slightly higher than the theoretical maximum performance of a single thermo regulator (Throughput is just under 200 g/s where a single regulator with maximum uptime could pull about 149 g/s), so going back to one would reduce throughput a bit.

Lastly, because the flow from the pump is intermittent I think a feedback loop would lead to pipe freezing, I had a similar problem with that in my Final Boiler Fantasy V build, which is why I didn't include the feedback loop as standard.

480W saved is nothing to sneeze at. Remember, power is technically limited in OU (yes, I know you can get around it).

EDIT: Removed wrong illustration
 

 

[WanderingKid]

Since this will probably end up as a collection of more experienced players on this topic, I'd like to ask a simple, overriding question I've had for a while: WHY?!

Okay, sure, it's fun... but deodorizers and 1/100th of my 4 billion kilograms of sand do basically the same thing, and doesn't use a drop of power.  Other than "Because it's there"... what is the value of this?  I'm currently liquidizing chlorine just to keep slime from being able to kick chlorine out of the way while I'm disinfecting it, but hyper cooling PO or O2 seems like overkill to me.

EDIT: Sorry, great tutorial btw.

[Sevio]

@Saturnus That's a useful tweak to save on thermo regulator count, but the power savings won't be as great as the 480 W you mention since those three thermo regulators aren't running nonstop and the power spent while they do run isn't wasted. The main difference will be steadier power draw and slightly reduced throughput.

It took quite some time to build the pieces and write this tutorial up though, and I don't have time right now to redo the entire guide and all the screenshots.

For those who are following the tutorial,  if you're interested in using the feedback loop you can adjust your thermo regulator setup according to Saturnus' schematic after you finish step 4 or 5. (make sure the regulators are idle before you make changes)

@WanderingKid

Deodorizers are easy to use to clean up new caves, but they generate duplicant jobs while doing so. An oxygen liquefier is something you can build once and then feed from wherever your polluted oxygen is coming from. It's a completely hands-off system once it's built and doesn't require dupe maintenance. This is good if you're going to exploit polluted water outgassing or morbs to produce polluted oxygen for you, which you then want to clean into normal oxygen.

Also, as I mentioned in the original post, this liquefier is a suitable stepping stone to an Aquatuner based liquefier which can create liquid oxygen much faster. Even if you don't have that much polluted oxygen to liquefy, you could use liquid oxygen with the aquatuner to make a pipe radiator that cools your base.

[WanderingKid]

19 minutes ago, Sevio said:

Deodorizers are easy to use to clean up new caves, but they generate duplicant jobs while doing so. An oxygen liquefier is something you can build once and then feed from wherever your polluted oxygen is coming from. It's a completely hands-off system once it's built and doesn't require dupe maintenance. This is good if you're going to exploit polluted water outgassing or morbs to produce polluted oxygen for you, which you then want to clean into normal oxygen.

Ah, okay, now I understand.  You're trading electrical power for dupe power for large quantities of PO -> O2 production.  Thank you, that didn't seem to want to get through my thick skull.

[midjones]

Thank you for this elegant design -- I love the compactness! Looks easy to build.  How long does it seem to take to start up? Any idea how much liquid O2 it can produce per day?

[Sevio]

@midjones Glad you like it! I haven't closely timed it but because I tried to put only the minimum amount of stuff inside the room that it needed, it should cool down to -200 C within a cycle or two once Step 4 is finished and the hydrogen is inside. I did a short throughput test earlier and it looks like it averages just under 200 g/s, so almost two dupes' worth of breathing. That's a bit under 120 kg of liquid oxygen per cycle.

[GreatGameDota]

Doesn't seem very power to oxygen efficient based on the fact you'll need a ton of those just to support one dupe and having something so compact only hinders efficentcy, but great job on explaining your build

[Lifegrow]

You know my feelings on these teeny-tiny builds, but a very nice guide for the newbies none the less - good work buddy  

[Townkill]

The problem i have with this build is you're going to eventually get a circuit overload when the gas and liquid pump kick on at the same time

[Sevio]

3 hours ago, Townkill said:

The problem i have with this build is you're going to eventually get a circuit overload when the gas and liquid pump kick on at the same time

It hasn't been a problem during my throughput test. Even when the pump is active, the thermo regulators aren't active 100% of the time. The pump also activates only in very short bursts, so even if everything were active during one single game tick, it's not long enough to cause overload damage.

[Sevio]

While doing another throughput test I came across a very strange problem after letting it run for a bunch of cycles - the hydrogen appears to be slowly depleting from the system. Where I originally put 12 kg of hydrogen in, the liquefier has now stalled due to too low pressure and only  4 kg is left in the system. This was very unexpected, any ideas why this might be happening?

[GreatGameDota]

On 9/20/2017 at 10:39 AM, Sevio said:

While doing another throughput test I came across a very strange problem after letting it run for a bunch of cycles - the hydrogen appears to be slowly depleting from the system. Where I originally put 12 kg of hydrogen in, the liquefier has now stalled due to too low pressure and only  4 kg is left in the system. This was very unexpected, any ideas why this might be happening?

Vents delete gas a lot more with the OutBreak upgrade. Especially with two different gases in the room. 

[eggsvbacon]

1 hour ago, GreatGameDota said:

Vents delete gas a lot more with the OutBreak upgrade. Especially with two different gases in the room. 

Nothing to be done then? SAD!

[Sevio]

R.I.P.

[Lifegrow]

On 20/09/2017 at 4:39 PM, Sevio said:

While doing another throughput test I came across a very strange problem after letting it run for a bunch of cycles - the hydrogen appears to be slowly depleting from the system. Where I originally put 12 kg of hydrogen in, the liquefier has now stalled due to too low pressure and only  4 kg is left in the system. This was very unexpected, any ideas why this might be happening?

I went into a bit of detail about this recently in another thread. It's partly caused by the vent deletion bug - but mostly cause by the changing in states.

It's easily witnessed in a co2 cooling chamber - because of the relatively small window between solid and liquid temperatures - and their ease to attain. The changing from solid debris (which can occupy the same tile as gasses/liquids) to a liquid state, and possibly bouncing back and forth like they occasionally do - you can literally watch your hydrogen (or whatever cooling gas you're using) getting deleted. 

I'm assuming the cooling gas is rushing into the tile space where the now liquified/solidified element was - only to be squashed when it changes state again. Same concept applies with cooling PO2 to liquid oxygen. It's why if you're going to use a "bubbler" design you must have a top up valve, ideally a filter set to an atmo switch.

[Sevio]

52 minutes ago, Lifegrow said:

I went into a bit of detail about this recently in another thread. It's partly caused by the vent deletion bug - but mostly cause by the changing in states.

I can see how state changes could cause gas to be suddenly compressed and deleted, however in the steady state the hydrogen is always in the top layer (and gets refilled by a vent in the top layer) whereas the PO2 gets refilled from the second layer (just above the liquid O2). And once in the steady state it seems like the PO2 just condenses into the existing liquid rather than creating a new liquid tile that drops down. But even knowing that there is a gas destruction bug with state changes, it's surprising to me that the hydrogen is getting deleted even though this one doesn't technically bubble, just conduct. The hydrogen isn't mixing in with the tiles where the PO2 is condensing.

[Lifegrow]

16 minutes ago, Sevio said:

I can see how state changes could cause gas to be suddenly compressed and deleted, however in the steady state the hydrogen is always in the top layer (and gets refilled by a vent in the top layer) whereas the PO2 gets refilled from the second layer (just above the liquid O2). And once in the steady state it seems like the PO2 just condenses into the existing liquid rather than creating a new liquid tile that drops down. But even knowing that there is a gas destruction bug with state changes, it's surprising to me that the hydrogen is getting deleted even though this one doesn't technically bubble, just conduct. The hydrogen isn't mixing in with the tiles where the PO2 is condensing.

Well having a pump that empties the liquid off the floor, which then spreads out, etc etc is another surefire way of displacing (and possibly destroying) gasses too. I'm assuming you have your liquid pump set to only be active above a certain level, but couldn't see it in your guide?

I normally set mine to "active if above 480kg" to leave a near full tile of liquid o2, without making a 2nd layer.

[Sevio]

8 minutes ago, Lifegrow said:

Well having a pump that empties the liquid off the floor, which then spreads out, etc etc is another surefire way of displacing (and possibly destroying) gasses too. I'm assuming you have your liquid pump set to only be active above a certain level, but couldn't see it in your guide?

I normally set mine to "active if above 480kg" to leave a near full tile of liquid o2, without making a 2nd layer.

It's set to "Above 50 kg" which is high enough to not deplete the tile before shutting off.

[Lifegrow]

29 minutes ago, Sevio said:

It's set to "Above 50 kg" which is high enough to not deplete the tile before shutting off.

Well it's occupying a full tile as soon as it's above 1g, so it'd probably make sense to allow it to build up more, then skim off once the tile nears 500kg - just for a bit more stability in the room. the extra 4 tiles worth of liquid oxygen would go a long way to keeping things running smoothly.

[eggsvbacon]

34 minutes ago, Lifegrow said:

Well it's occupying a full tile as soon as it's above 1g, so it'd probably make sense to allow it to build up more, then skim off once the tile nears 500kg - just for a bit more stability in the room. the extra 4 tiles worth of liquid oxygen would go a long way to keeping things running smoothly.

So it might not be RIP?

[Sevio]

@eggsvbacon It's still RIP, as that would only slightly reduce temperature fluctuations, but those aren't actually harming anything as long as the Liquid Oxygen doesn't evaporate. I actually designed this liquefier with minimal total heat capacity in mind to lower the startup time as much as possible.

As long as you can avoid unnecessary phase changes and you have enough area for the heat exchange (for a radiator or conductor), I actually don't see value in adding thermal mass for no reason with things like doors and high capacity tiles. Usually that can be achieved with just a small layer of liquid oxygen on the floor of the room. But if the gas destruction bug can't be avoided, then a radiator system with the lowest total heat capacity possible is probably what I would lean towards.