# Question about water cooling and heat transfer mechanics

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I have an enclosed box of hot water I want to cool with aquatuner with the steel door thing. This works in principle. The question is about the gas in that chamber. It contains 1.5 kg of oxygen per tile. Which I assume would be compressed when I pump in water. Does this oxygen mess with the heat transfer/cooling? Like would it slow the cooling because it contains heat itself (it seems to heat up quite a bit when I pump in the water), or something to that effect? Making it a vacuum just in case is not hard, but I'm wondering about the game mechanics around this.

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1 hour ago, Steve8 said:

I have an enclosed box of hot water I want to cool with aquatuner with the steel door thing. This works in principle. The question is about the gas in that chamber. It contains 1.5 kg of oxygen per tile. Which I assume would be compressed when I pump in water. Does this oxygen mess with the heat transfer/cooling? Like would it slow the cooling because it contains heat itself (it seems to heat up quite a bit when I pump in the water), or something to that effect? Making it a vacuum just in case is not hard, but I'm wondering about the game mechanics around this.

Gas has such a small mass and specific heat that it will have no measurable effect.

This said, I'm assuming that the gas is not between the cooling and the water. That would screw things up.

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I have an enclosed box of hot water I want to cool with aquatuner with the steel door thing.

The Aquatuner does not delete heat! Every ounce of energy pulled out of the water ends up going into the aquatuner. You need a viable way to get rid of the heat, or the tuner will cook itself to death. Typically this involves placing the tuner in a steam room under a steam turbine. The aquatuner heat goes into the steam and the turbine transforms hot steam into hot water, deleting a large amount of heat in the process.

You don't always have to cool down huge amounts of water. Many places do not care about water temperature at all. Good destinations for hot water include electrolyzers, cooking recipes, pincha peppers and oil wells/reservoirs. Don't worry about cooling down water if the consumer doesn't care.

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I got that part working already. I have an aquatuner with a steam turbine that cools a box of polluted water. That box is connected to my hot water box with diamond windows and a steel airlock. This is the sandboxed version. The real one as some tiny differences, but is basically the same:

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Many places do not care about water temperature at all.

I'd say some things would care if I fed them 70-95° water from a cool steam vent  The electrolyzers would take it. The wiki claims that feeding it hotter water is better, but I'm using an AETN to chill the oxygen. The AETN can cope so far, but if I were to expand it, it would struggle and not reach 0°C oxygen anymore. In sandbox I found out that if I feed it pre-cooled water, I can use that water to chill the oxygen in the SPOM chamber via radiant pipes. So it does get  electrolyzed hotter. But end result is cooler, which means the AETN can reach a lower output temperature. Sure I could use an aquatuner "properly" and just cool the hot oxygen directly, but its main purpose is to deal with the steam vent!

In any case by cooling it down between eruptions I can use the water for basically anything and don't have to worry about keeping different water sources. And the aquatuner is there anyways, so it may as well do some work when the steam vent is dormant. Having its constant load on the power grid is good too as it burns of the excess hydrogen from my electrolyzers.

Maybe it's not the most effective, min/max-y thing, but I like it so far.

But the question is more theoretical than practical. The overall reasons for this aren't too important. It's about the difference between a vacuum and an oxygen atmosphere in regards to the cooling mechanics here. Mostly in the top chamber, but I heard that having the steam vent in vacuum helps too with condensing the steam. So I'd like to understand how the gases affect the cooling process here.

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18 hours ago, Steve8 said:

And the aquatuner is there anyways, so it may as well do some work when the steam vent is dormant. Having its constant load on the power grid is good too as it burns of the excess hydrogen from my electrolyzers

I know that this is not what you are asking about, but cannot resist pointing out that this is somewhat backwards logic. You do not need to artificially create load on the circuit to burn off excess hydrogen. Just have a simple bridge-based overflow that goes to a hydrogen generator that is not connected to any automation, so that it runs every time the hydrogen backs up to the bridge. This way you can at any moment decide to e.g. create more gas storage tanks behind the bridge to start banking for your rockets (eventually it will be the hydrogen that you will want more of, and you will be looking for ways to get rid of excess oxygen), and the overflow will still work. This should have nothing to do with your trying to waste energy on cooling water.

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18 hours ago, Steve8 said:

I got that part working already. I have an aquatuner with a steam turbine that cools a box of polluted water. That box is connected to my hot water box with diamond windows and a steel airlock. This is the sandboxed version. The real one as some tiny differences, but is basically the same:

You're cooling the water in the top chamber right? The air on top shouldn't have any noticeable detriment to the cooling provided, but the steel door trick by itself as a cooling element will provide relatively slow heat exchange without other heat exchange elements like radiant pipes. Also, you do know you'll have to pump that water back out after you cool it right? You might consider running it through radiant pipes instead, the pipes will significantly improve thermally conductivity and having the water in motion will help spread the cooling, you can use a liquid reservoir to temp balance your water supply.

Another suggestion if you haven't already considered it, is splitting off your water supply for hot and cold lines. Hot water for electrolyzers, oil wells, etc. and cold water for life support systems to keep living areas cool.

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Yeah, I know I have to add some more pumps. I did so in in the proper game and added a liquid lock in case I need to mess with anything in there. So I could add some radiant pipes.

Yeah cooling is relatively slow without piping, but it's a decent sized tank it should last a while given my current consumption. I could have three tanks: hot, cooling and cold. Lots of pumps though...

3 hours ago, Majestix said:

Just have a simple bridge-based overflow that goes to a hydrogen generator that is not connected to any automation, so that it runs every time the hydrogen backs up to the bridge

I still need some power draw for that generator to run or it will just fill up eventually. I play very slowly and and there were really times where I used almost no other power in the base. Basically everything idling. Running the aquatuner is no issue since I have two natural gas geysers right next to each other and the steam turbine contributes some too.

At the point where I'll need to make hydrogen for rockets I can make another electrolyzer setup. Or just reroute the hydrogen

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28 minutes ago, Steve8 said:

I still need some power draw for that generator to run or it will just fill up eventually.

Last I checked, this is not how generators work. If you don't hook up any automation to the hydrogen generator, and attach it to a battery, it will just burn off everything it receives (unless something was changed very recently).

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Maybe more because the battery slowly discharges and needs to be reloaded. That could have worked, yeah.

Well, even without the the aquatuner drain, it should no longer be an issue now. Just needed to scale up things

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46 minutes ago, Majestix said:

If you don't hook up any automation to the hydrogen generator, and attach it to a battery, it will just burn off everything it receives (unless something was changed very recently).

That sounds about right. Only the hamster wheel is capable of automatically shutting down at full battery.

Last I checked, power generators in general have weird behavior when automation shuts them off. Coal generators will abandon and reject refilling jobs, which is a real pain. Hydrogen generators do the same, except worse. If the gas network has a packet flowing into the hydrogen generator, the packet will be destroyed. It's not very noticable with the 90g packets but when a full 1kg goes POOF it gets pretty costly.

You can minimize the hydrogen destruction by very rarely turning the generator off. Each shut down is a potential packet lost. Another way is to use gas valves. Keep the generators "always on" and throttle the gas going in. When the battery is full, turn the valve off and let the generator starve.

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This thing about cooling your water first and then using cold water to feed electrolyzers. Even if you set up your pipes to pre-cool the oxygen on its way out, you're wasting a significant amount of power and printing heat.

The thing is that water has a much much higher specific heat capacity than the resulting oxygen and hydrogen. So, there are a few approaches you can take that spend about a quarter as much power cooling and also delete heat instead of creating it.

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55 minutes ago, avc15 said:

The thing is that water has a much much higher specific heat capacity than the resulting oxygen and hydrogen. So, there are a few approaches you can take that spend about a quarter as much power cooling and also delete heat instead of creating it.

And here we go again with the constant min/maxing. If the entire purpose of this would be too have chill oxygen, then yes. Of course it would better to just cool the oxygen at the end instead of the water going in. I know that the normal way is to just run the oxygen by an aquatuner. But I use an AETN for that which is basically free cooling. And the infrastructure is all there. It works fine for now, but it does have its limits. The more you try to feed fit it the warmer the oxygen gets. It would still be perfectly usable if it were warmer, yes, but I really like my cold oxygen to cool everything a bit.

It may be possible to use the same aquatuner for all of this, but I didn't want to overcomplicate things for now. I never built a cool steam geyser tamer before, so I left it relatively simple. It's hard to experiment with these things in in a regular game as large changes are extremely difficult to build.

Also, technically I'd not be directly electrolyzing the cool water. It would suck up the signifcant heat in the SPOM chamber and heat up in the process. And then the AETN doesn't have to deal with such a large temperature difference. I can't remember the numbers though. Is it the best way? Probably, not, but it worked.

In any case, the water from the steam geyser gets cooled anyways. I have other uses for it, like science, farms, etc. which do need colder water. It's mainly there as a renewable water source. Electrolyzing is not why I built this. That was just something I discovered when my sandboxed my SPOM setup and may do later. I haven't decided yet. I have enough oxygen and plenty of polluted water pools I can get rid of for now. But for just regular use the geyser produces more water than I need at the moment. Sure, I'd be running the aquatuner more than I really need to. I could just cool enough water I absolutely need and stop the thing when I have enough for that. That would be the efficient thing to do in this scenario. But it's just not that big of a deal for me. Maybe when I run into power issues, later...

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If the water going into your electrolyzers is below 70c, you're printing heat. If it's above 70c, you're deleting heat. If your feed is 40c and you're passively exchanging heat, that inlet water won't be higher than 55c at the electrolyzers. (Water has quadruple the heat capacity)

I don't understand having contempt for efficient design. Piping in cool water is an active hinderance, not just passing up a cost savings. Doing so creates heat that wouldn't exist otherwise.

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15 hours ago, Steve8 said:

And here we go again with the constant min/maxing

Yes it is a type of min/maxing, but it's the good kind where we try to be as lazy as possible.

Cooling down water for electrolyzers is a lot of extra effort. You don't NEED to spend that extra effort. pass hot water into the electrolyzers, and worry about the much much easier job of cooling down the oxygen.