air circulation in a greenhouse

[ddrei]

help me out here...

i have a nice base with breathable air and everything and i started my greenhouse. started with 12kpa of pure co2 and did grow some plants. so far so good. o2 got added to the atmos as expected.

i used the same setup atmos wise as for my base:
gas line - valve - pressure regulator set to 15kpa - passive vent and
passive vent - back pressure regulator to 12kpa - valve - waste line

the problem i have now is that o2 gets added to the room quicker than i can cycle it. meaning my co2 % drops below 10% after a while and i fear that the plants won't grow anymore.

can anyone give me any hints on how to cycle the air in a way that i constantly get co2 pushed into the room and remove o2 at the same time? i tried with air filters as usual and active vents but that did not work really. also creating a bigger draft (30kpa in - 10kpa out) did not help.

thanks in advance!

edit: i basically want a system that works on its own - also for huge amounts of plants. currently i have to vent the whole room after a crop cycle and sometimes in betweeen. then reheat it quickly and continue. not really a great system :(

edit 2: temperature i have under control with a heating and a cooling system.

[Adam De Beers]

check this, maybe it helps:

https://www.youtube.com/watch?v=jBim961qQwc

[Adam De Beers]

I am removing O2 from the greenhouse with portable air scrubber, which is piped to main filtration line

when the pressure drops, new CO2 gets pumped into greenhouse to fill the gap after O2

[ddrei]

i don't like the portable air scrubber solution. it sucks so much air out of the room in an instant.. when i don't have the co2 in my pipe system at the correct temperature already, the room gets cooled down a lot.

i basically want an always on system that does not need manual items like the scrubber.

[Adam De Beers]

I keep my CO2 tank in the base so it has ambient temperature, I am using scrubber, because if you plant the crops, you need to return there anyway

[mariosevin]

are you pumping in just CO2 or is it a mix? if you are using just CO2 then try using more than 1 inlet. I have my gas lines are all seperate and use logic to allow only the gas I need or want into the room. It does take a long time to get set up but so far it works fine for me.

[Bunyan]

OP... first, I am not by any means an expert on this part of the game, but I've read a ton, watched a bunch of videos, and have found 2 systems that have worked for me.

The first and easiest is in a closed off hydroponics room...like you I started with a PR....Then hooked up an atmospheric filter to filter out O2 but cycle back into the room the CO2 "waste"...instead of this running constantly, I had this hooked up to a sensor and logic that if the oxygen rose above 30%, it would kick on. I also had a BPR set up at 101kpa to also feed into the O2 output, just in case... But I found this required more oversight and I never really felt like it was truly set-it-and-let-it-run.

That said, what I've settled on since then is more complex but I'm much more pleased with it. In my newer setup, I do NOT have the hydroponics sealed off. Instead it is in a room open to the main hallway of my base, supplying me with constant oxygen. I run my base on 10-20% O2, 40-45% N, and 40-45% CO2....So with this I don't actually need a separate filter system for my hydroponics room. (BTW, these percentages are for flex, so my system doesn't kick on at every 1% change of gas mix.) Each of the gases are fed individually to the base with logic circuits...If the pressure gets too high, gas is pumped in mass out until the pressure is correct. (So they are mixed in base room, not in the pipe.) The only thing I have a sensor on to filter OUT is volotiles (H) and pollutants (in one singular atmospherics filter)...All gases taken out of the atmo are put back into my gas filtration system and made ready to use again. So with this mix, plants grow, you can breathe, things rarely if ever combust, and you have a self-feeding system that keeps perpetuating itself.

Again, I'm not an expert, and all of these ideas were just put together from learning from other people's good (and some not-so-good) examples, but hopefully this helps.

Oh--and I DO have a rapid de-pressurization that I can hit if I need to clear the base of gas to rip out a wall or something.

[ddrei]

thanks!

i will try the multiple inlet thing and maybe even the co2 in the base. never thought of anything other than o2/n2 mix.

[Weyland-Yutani HR]

Here's how I got around this using logic chips.

I have a main pressure fill for my greenhouse. 75/25 N2/O2 so I can work without a suit. This is controlled by logic IF pressure < 100, open mixing valve.

There's then a separate volume pump for CO2. Logic control is IF % CO2 < .02, turn on CO2 pump.

Now I have my oxygen filtration. The filters are actually N2 and CO2 so those get sent back into the greenhouse and oxygen is sent for processing.
Logic here is IF % O2 > .25, start filtration.

I actually setup a buffer to pull O2 until the percentage gets down to 25.

Add in automatic temp controls and your greenhouse atmosphere will regulate itself. I've left that setup alone for several game days and the atmosphere is perfectly regulated when I go back in.

If you're wondering how to get the odd decimals in memory you'll need an extra memory chip, logic writer, and a math chip. Set the number you want to work with in memory, divide by 100 in math chip and write it to the final memory chip where the setting will be.

[robcreid]

I have a similar setup to you. I added a filtration unit with an O2 filter in it with passive Vents on the Input and and Waste. The O2 from Output connects to the existing waste line.

I have also seen someone elses setup that has a logic controlled Volume pump on the incoming CO2 gas line. Volume pumps have higher throughput than a regulator. They had logic that detected if CO2 % was below a threshold and activated the volume pump.

[ddrei]

do you only use passive vents on the filter machine or also a pump between it?

[Weyland-Yutani HR]

Originally posted by ddrei:

do you only use passive vents on the filter machine or also a pump between it?

I only use passive vents on those. They provide their own suction.

[Bunyan]

Originally posted by ddrei:

do you only use passive vents on the filter machine or also a pump between it?

At first I used passive vents, and this works if you know your pressure behind the vents will be less than the room it's sucking from... Like if your vents are piped straight to your atmo filters.

I eventually changed that to active vents which also act like valves when off, so nothing can leak back into the room if the room pressure is lower than the pipes. For my setup, this really helps... My setup has active vents --some on logic control and some on manual "fast depressurization" setup--that feed in a safe "holding" area (basically a pipe that feeds my filter, but before the filter I attached 2 (to start) and eventually 6 (now) of the large stationary ball tanks to temporarily hold any gas fed to the system. The filters can then filter at their leisure. Basically they act as holding tanks while the filters take their time doing their thing. This means I never worry about pipes (or anything else) bursting from sudden changes in pressure from being fed a whole base's worth of gas. This also means I don't lose anything from a BPA venting.

On a side note, this is just one of many changes I made AFTER fishing through my base for burst pipes or blown electrical...the work of repairing things has driven me to making sure my stuff is as protected as possible