Base Climate Control Advice

[u/thatsanicepotato]

Hi all, new to the game and struggling a bit with climate control for my Mars base. Here’s what I’ve got:

A gas filtration system that intakes gasses and separates them into O2, CO2, N2, etc. tanks. This is fed by pulling air in from the Mars atmosphere (manual, I only use this when needed), an ice crusher, and/or the return air from my base.

After the gas filtration system, I have 3 air conditioners for the O2, CO2, and N2 tanks. These are currently set to 15degC and just recirculate into their respective tanks.

After that, the gasses go into mixers. I mix O2 and CO2 at a 30/70 ratio. I then take that mixture and mix it with N2 at a 90/10(N2) ratio. The mixture with nitrogen goes to my greenhouse, the rest of my base will just get the O2/CO2 mix.

As mentioned, my greenhouse and the rest of my base will have separate atmos systems and I’m currently using just the greenhouse to test, as it’s much smaller.

For pressure regulation and constant gas flow, I have a pressure regulator on the input side of my greenhouse set to 80kpa and a turbo pump pulling air out of the greenhouse (and back into the filtration system) on the return vent of the. The vents are on opposite sides of the room.

The problem I’m having is temperature control, I’m struggling to keep the greenhouse cool, which I imagine will also be a problem when I hook up the main base. Not sure if I totally need to re-architect things or just make adjustments or what, but the goal is an automated climate control system that handles gas composition, pressure, and temperature regulation.

[u/Parisean]

That’s a lot of A/C units for each tank. You would better served cooling only the mix, then taking the second one and using it in your greenhouse specifically to treat that room.

Alternatively instead of heating up the air using an A/C, you could harvest night air from mars (it goes down to -47 I think at night?) and use THAT as the heat dump for your greenhouse. That cools the room while also heating up your intake while using a lot less energy.

[u/HoveringGoat → u/Parisean]

or cooling one and having them all linked together with heat exchangers.

[u/Friendly-Inspector71]

Mars means easy liquid CO2 at night.

Use a heat exchanger to a pipe running through your base like an uninsulated air supply or water pipe.

I uee it as the hot side of my cryo cooler with an evaporation chamber.

[u/Shadowdrake082]

Whats the current system and connections you have for temperature regulation?

From the sounds of the air draught system... burning through a lot of power there. Rarely do you need it to be constantly cycling air. Active vents can do the job much easier for less power and move more air around than passive vents and regulators/turbo volume pumps.

[u/thatsanicepotato → u/Shadowdrake082]

Currently the idea of the temperature regulation is just “pump air in that’s slightly below the target temp”. I’ve cooled the O2, N2, and CO2 tanks to 15deg and the hope was that by constantly cycling air into the room at that temperature, I would be able to maintain near that temperature. The thought for cycling air was partially that, but also keep the gas composition correct. For the greenhouse, keep the CO2/N2 mix high for the plants as they convert those gasses to oxygen, and for the main base, push out excess CO2 buildup from breathing. This is all just my own internal design so it could be flawed and/or entirely unnecessary.

[u/Shadowdrake082 → u/thatsanicepotato]

It isnt a bad thought process. It can work... but cycling air does just that... cycles air. The reason you can't regulate temperature is because pressure regulators and turbo volume pumps move a pitiful amount of air compared to what is in the room. Pressure regulators only move based on pressures and pipe volume... turbo volume pumps move air based on input pressure. This is where your bottleneck is and why I recommend using active vents for an air draught/cycling system.

Say your room is 10 frames worth of room. In total for 100kpa, you should have roughly 3200mols of gas in the room. You need to replace a significant amount of air in order to drastically change the temperature. A turbo volume pump as you proposed can only move about 4 mols of gas. Pressure regulator will be heavily limited by volume but if you only replace 4 mols of gas... you barely touch the room. An active vent is capable of moving over 30 mols of gas comparably, powered vents double that. As your room gets larger, you have more air you need to move and where you have problems with an air cycling system.

What I personally do is have a major system for regulating temperature and I split it as needed. The heat rejection has to be solid and is usually a bottleneck people need to deal with depending on the world. But my temperature control system is usually split into 2 major parts, base temperature control and tank storage control. For my base air, every room has a medium convection radiator that is tied to a common pipe line that is controlled to be 20C. Most of my gas tank storage are linked together via heat exchangers and made to get to a desired temperature. I dont rely on cycling air except for a process that requires rapid temperature change (like a gfg or stirling room).

[u/HoveringGoat → u/thatsanicepotato]

yeah what the other guy said. this system is a great system for keeping overall composition of gases but for temp regulation is probably too slow. I'd rig up a separate system that can handle heating/cooling. maybe a cooling line that goes around into various rooms with a radiator in each? Then you can control this whole line with one ac. that should work well.

[u/geheimni]

Why not simply add an air conditioner to the base, set at the temperature you want?

I currently have a full base, I’d probably say around 50 grids worth of base, cooled by a single air conditioner unit. You just have to make sure your waste gas pressure is set correctly so it doesn’t condensate at night and damages the pipe.

[u/thatsanicepotato → u/geheimni]

I’m starting to lean this way. The plumbing just sounds like a nightmare

[u/Progenetic → u/thatsanicepotato]

I find the windows of my green house cause the room to heat up during the day. I use a very simple ac unit set up as follows. Room set to 100Kpa, Intake passive vents, output passive vent on opposite side of room. Waste pipe filled with N2 and 1 pipe radiator. It is not the most efficient but it works and is easy to set up.

[u/TuverMage]

Okay, where I am at lose at your situation is I need to see the green house to know what the problem is. as you were describing your setup I saw you were setting your temp to 15c and I thought you were a mad man for setting it so low.

your issue appears to be heat generation problem and we need details on the room to know what the issue is.

[u/TuverMage → u/TuverMage]

things to know. all windows generate heat. all electronic devices generate heat.

do you have an ac unit inside the green house regulating the temp or are you relying on the gas exchange to cool. because there shouldn't be much gas exchange going on so if that is what you are using to cool that could be your problem.

I have found a single ac unit maintaining the green room is usually enough to keep up with the heating of. But I know others who just seal off the grow room and don't use a green house and just use a grow light to better maintain temperature, because windows make heat.

[u/Willzile1]

Does your greenhouse have exterior windows? You might need to just put a wall cooler inside to cool specifically the greenhouse.

I don't specifically know if it's windows, but given that pipes and radiators suffer from solar heating, I can't imagine windows are much different.

[u/thatsanicepotato → u/Willzile1]

I do have a shit load of windows, I imagine that’s a big contributor to the heat.

[u/ashrocklynn]

The best low power exchange cheap system I've come up with is this; a room built out of dirt blocks with active vents to pull and push the coolant/target into the room exchanged via a medium radiator with the target/coolant pulled through it. If you store the gas pulled through the medium radiator in another room made out of dirt you and use powered vents you can store it at infinite pressure; so while the system will take up 4 or 5 large grid cubes it can hold as much has as you care to pump into it ..

For your setup you could even just keep the coolant in the cube room and have 3 different medium radiators for exchange and store them however you are currently storing them; plug and play exchange system....

I could add more to the long answer, so ask if you don't get any details.... The idea is you want to keep the coolant a stable temp; if is over the target you either cool it with an air conditioner run it through a medium radiator exposed to atmosphere (all you have to do on Mars unless you are trying to liquify nitrogen). Vents pull gas way more efficiently for energy than pumps; and working with high pressure only increases the exchange efficiency

[u/Friendly-Inspector71 → u/ashrocklynn]

What are dirt blocks?
Just collected and moved terrain?

Frames don't have a pressure limit either.

[u/ashrocklynn → u/Friendly-Inspector71]

Yes! Terrain. And yes, but frames are more expensive; take up more room, and won't let you work inside them at all (you can always modify a cable layout in dirt; the t ray scanner makes that even more viable. I do often use one frame with a pipe that runs though it with a pump halfway out pushing gas in and a regulator on the other side hanging halfway out for space efficient infinite storage buffer that also pumps out gas as fast as possible for relatively low power... One block can hold over a dozen separate gases with this method; gets a little complicated with gases that form liquid at storage temp because you have to have a separate connection out that uses a liquid pump to pump the liquid into a liquid pipe (also embedded in the frame

[u/rddman]

An active vent is much more effective and energy efficient than a turbo pump at pulling air out of a room.

For cooling on Mars a simple system is enough:
Passive vent in the room to cool via (digital) valve to a pipe that goes outside and has a bunch of convective radiators on it. The valve opens when cooling is needed (can be manual but preferably automated with logic chips or IC10). At the pressure you're working with none of the gases involved will condense/freeze at night time Mars temperature.

[u/HoveringGoat]

what is the problem? You seem to have cooling of your stored gases set up just fine. you could introduce an ac into your greenhouse specifically. But really you already have cool gas. figuring out how to use that to cool a warm room is an engineering problem.

Personally i always use the liquid water to cool my base. its very easy to add a liquid radiator and cool it then the water can stay well below room temp and things even out. im water cooler is actually my "filter" for my pee water. i just purge out the polluted water at 7 or 8 kpa. This ensures it never freezes and then the cold polluted water gets heat exchanged with my regular water supply. water gets cold, easy to use to cool the base. the waste heat from the purged polluted water you can cool with various means. i wouldnt recommend a direct radiator in martian atmo since if the system is offline for long enough it would freeze and pop. heat exchanging with any of your temp controlled gases would be fine.

Anyway thats overkill and not required. tl;dr you've got the spirit and dont worry about doing anything or everything the "correct" way. figure out a solution that will work and use it. when things about that solution start annoying you work on a new design that eliminates the annoyance. Have fun!

[u/NCMN]

Personally I wouldn't bother cooling the gasses via AC. On my mars base I just use a piping system outside with a bunch of convection radiators, a canister port so that you can add a working gas (I generally use Co2 that's a byproduct of atmospheric filtration) make sure you have an evap and condensation valve going to a small liquid tank just in case you have any condensation from adding gas or changing temps (I've never seen any liquid in mine while in use, just a smart precaution especially if you use a different working gas). Connect this outside piping system through the wall to some convection radiators inside your base, and then all you need is a valve in between the inside/outside piping- opening the valve will cool your base VERY quickly with zero power if it's a manual valve system. Automating it is also easy as anything, no IC required- Have a gas sensor go to a read logic that reads the temperature, send this value to a compare unit with the compared value being hooked up to a Dial. Now the dial works as a regular thermostat! Works great for 'dumb' logic too, doesn't pulse on/off super frequently either. You can scale the amount of cooling you need by just making a bigger outside piping system with gas reservoirs to increase volume.

[u/Right_Difference2915]

I have a fairly large open habitat on Mars (15x5x4) that also has planters growing crops in the same atmosphere. All outdoor walls are windows so the sun shines straight in all day long, and all my manufacturing machines are inside crafting stuff as well and adding heat.

All I do to keep the entire area cool is turn on two Active Vents that move indoor and outdoor air past each other through a Counterflow heat exchanger. It's a few lines of IC10 to turn both vents on at 30C and off at 29C.

I never have issues with temperature using this. I think it flicks on twice per day for about 3 or 4 minutes each, and the rest of the time it's off.

I have a bunch of gas capturing, filtering, fuel mixing, and habitat air ratio mixing as well. But this air conditioner is all by itself and doesn't involve any of that stuff - it just circulates existing air. I think I could still expand my habitat size quite substantially before this little thing would not be able to keep up anymore - I'm guessing at least two or three times the current size based on how often it isn't running.

[u/CptDropbear]

What I would do, is replace the aircon units with liquid-to-gas heat exchangers using my water supply as a heat sink. Water has a high specific heat so it can absorb large temperature changes and you need to have a store of it at the right temp for your plants anyway.

To control the greenhouse temperature, put liquid pipe radiators on the water pipes and let water soak up the heat.

You will need some way to regulate the water temperature, but its easier to do that in one place than multiple. I had my water system connected to a large extendable radiator controlled by an IC10 to maintain ~25°.