Is the electrolyzer heat-deleting?

[ProfMembrane]

If I use very hot water in the electrolyzer, will it produce very hot oxygen, or does it come out at a standard temperature?  I want to know if this is a good or bad use for geyser water or runoff from smelting.

[Amara3113]

5 minutes ago, ProfMembrane said:

If I use very hot water in the electrolyzer, will it produce very hot oxygen, or does it come out at a standard temperature?  I want to know if this is a good or bad use for geyser water or runoff from smelting.

It comes out at 70c, no matter how hot or cold of water you use.  

[landromat]

1 hour ago, ProfMembrane said:

If I use very hot water in the electrolyzer, will it produce very hot oxygen, or does it come out at a standard temperature?  I want to know if this is a good or bad use for geyser water or runoff from smelting.

Yes. Just pump water straight from the geyser to electrolyzer through insulated pipes and you'll get 0 heat and 70 deg oxygen.

The only thing you have to cool water for is farms

[Tranoze]

Yes and no,  if the water is above 70, it heat deleting, if not, heat addition.

Always use 90C water for them.

[trukogre]

1 hour ago, tranoze said:

Yes and no,  if the water is above 70, it heat deleting, if not, heat addition.

Always use 90C water for them.

Since oxygen and hydrogen have different specific heats than water, it's actually quite a bit more complicated than that.  since ONI as a whole doesn't obey conservation of mass/energy, in the end what we often care about is temperature, not heat, so you could rephrase it that way if you so desired.

 

p.s.  if ONI did obey conservation of mass/energy, then:

if you look at wikipedia, the enthalpy required for formation of water is around 290 kiloJoules per mole.  Current methods of electrolysis are about 80% efficient.  285 kJoules/mole * (1/80% efficiency) * 55.55 moles of water per kilogram * 1 kilogram water/second used by electrolyzer = 19,790,000 watts needed to run an electrolyzer breaking down 1 kg/second of water into oxygen and hydrogen.   slightly more than 120 watts, as it turns out.  Elsewise in wikipedia on the article about electrolysis it mentions that 

Practical electrolysis (using a rotating electrolyser at 15 bar pressure) may consume 50 kilowatt-hours per kilogram (180 MJ/kg), and a further 15 kilowatt-hours (54 MJ) if the hydrogen is compressed for use in hydrogen cars.^[21]

^{Since 50,000 watt hours is 180,000,000 joules, and 19 million watts for 9 seconds would make 1000g of hydrogen in the above calculation, and 19.8million * 9 is around 180 million, this math checks out.}

For some reason, the people complaining about various unscientific quantities in ONI never complain that electrolyzers don't require 20 million watts to work.  The fact that they have a constant temperature output really cheeses them off though.  The power requirement seems more basic than the temperature of the output though, so I wonder why they don't object to that first??

[ToiDiaeRaRIsuOy]

Simple to calculate:

-Water has 4.179 (J/g)/K heat capacity, oxygen has 1.005 (J/g)/K, and hydrogen has 2.4 (J/g)/K.

-Electrolyzer converts 1000g of water into 888g of oxygen and 112g of hydrogen, each second (assuming 100% erfficiency and no bugging out), and puts out both gasses 343.15°K.

-Let's assume you pump in 363.15°K (90°C) of water.

That gives 4.179=(J/1000)/363.15 or kJ=1517.60 worth of energy/heat you pump into the system. You pump out oxygen and hydrogen, both at 306.241 kJ and 92.239 kJ respectively, or 398.480 kJ combined. Each second for the record. 1517.60 kJ into the system gets converted to 398.480 kJ.

So you are deleting around 74% of the heat at 90°C input of water and of course assuming your electrolyzers don't do weird stuff like deleting gasses (if they do, that percentage goes further up).

[hostagesaverfuz]

gases from electrolyzer are set at 70 degree ,but i won't call it heat deleting because the only use for oxygen is for breathing, and oxygen cannot turn into recyclable resources. Pwater evaporation is similar

[ToiDiaeRaRIsuOy]

4 minutes ago, hostagesaverfuz said:

i won't call it heat deleting because the only use for oxygen is for breathing, and oxygen cannot turn into recyclable resources. Pwater evaporation is similar

It's heat deletion, period. You can reason how useful the end product all you want, but that's really beside the point, especially if you use electrolyzing not for oxygen primarily, but for heat deletion. SImple example: I use water as a coolant for my metal refinery. I will keep pumping that water around until it comes close to the evaporation point The hot water afterwards will be dumped in an electrolyzer. Now I suddenly deleted the vast majority of the heat produced by the metal refinery.

For the record, I don't immediately consider it as a bug exploit due lack of choices regarding cooling. I think once the game developers start to invest time into that, we will be able to get rid of this kind of heat deletions tricks, which kinda are unfortunaly mandatory at this point.

[trukogre]

8 minutes ago, ToiDiaeRaRIsuOy said:

It's heat deletion, period. You can reason how useful the end product all you want, but that's really aside the point, especially if you use electrolyzing not for oxygen primarily, but for heat deletion. SImple example: I use water as a coolant for my metal refinery. I will keep pumping that water around until it comes close to the evaporation point The hot water afterwards will be dumped in an electrolyzer. Now I suddenly deleted the vast majority of the heat produced by the metal refinery.

In a certain technical sense it's heat deletion...it's not heat in a 'real physics' kind of way, because electrolysis in the real world doesn't free energy, but requires it, vast quantities of it, so everything you're talking about completely contradicts the real universe.  In the "cooling your metal refinery' way, what matters isn't really heat so much as it is temperature.  No one talks about dupes as 'effective heat deleters', but a dupe breathing 27 C oxygen is certainly deleting heat. 300 K * 1 J/g/K * 100 grams of oxygen/second = 30,000 dTu per second, per dupe. So 20 dupes is 600,000 dTu heat deletion, technically.  Wow, that's like 8 AETN, why do I even need to cool my base at all?  It turns out the absolute heat change (measuring heat from 0 kelvin, like in the real world) in your base doesn't really matter, because ONI doesn't obey mass conservation.  What matters is whether things entering/leaving your base leave or enter at a temperature different from your desired temperature, usually around 20 C.  If we imagine some new type of heat, where objects have 0 heat at 20 Celsius, and more or less as they differ from 20 C, call it dupliheat, doing our calculations in dupliheat is actually much more relevant to most gameplay.

[ToiDiaeRaRIsuOy]

11 minutes ago, trukogre said:

In a certain technical sense it's heat deletion...it's not heat in a 'real physics' kind of way, because electrolysis in the real world doesn't free energy, but requires it, vast quantities of it, so everything you're talking about completely contradicts the real universe.  In the "cooling your metal refinery' way, what matters isn't really heat so much as it is temperature.  No one talks about dupes as 'effective heat deleters', but a dupe breathing 27 C oxygen is certainly deleting heat. 300 K * 1 J/g/K * 100 grams of oxygen/second = 30,000 dTu per second, per dupe. So 20 dupes is 600,000 dTu heat deletion, technically.  Wow, that's like 8 AETN, why do I even need to cool my base at all?  It turns out the absolute heat change in your base doesn't really matter, because ONI doesn't obey mass conservation.  What matters is whether things entering/leaving your base leave or enter at a temperature different from your desired temperature, usually around 20 C.

You do realize I only gave a very simple example. The point primarily being water having a much larger heat capacity, which can either lead to heat death to new people who underestimate what that high energy capacity can do, or can lead to simple way of dumping annoying amounts of heat into water.

Yes, that is primarily a problem when the temperature is too high. but the amount of heat something can hold will play a bigger role when you get fancy with oil cookers, or dealing with stuff at the asteroid surface. For instance, having 20ton chunks of regolith at 300°C laying around in a sensitive area will be able to nullify quite a few wheezeworts of cooling, the problem being the huge amouge amount of heat/energy that is stored in the regolith. That is me calling from my own experience: I tried to convert the gravitas centry into a forward colony to get rid of wasting dupe time. The centre already got bombarded by meteors and hundreds of tons of regolith already got in the structure. I set up oxygen production in there, but the regolith quickly heated it up to over 200°C. 20 wheezeworts could not keep up with cooling, and the regolith did not cool down in any significant way just because of the high mass.

[trukogre]

Yes, 20 ton chunks of regolith at 300 C are a much bigger problem than most other things you encounter, and using dupliheat would show that difference from less extreme examples even more clearly than using traditional heat. Great example of how calculating from 0 kelvin is usually a waste of time in this game!

[ToiDiaeRaRIsuOy]

It's also great to know for electrolyzing. Let's put all the fancy stuff about abusing heat deletion aside: at which temperature would you prefer not to electrolyze the water? I think that can be relevant because when presented with choice, it's good to know which pond you want to use for electrolyzing and which not.

To do that, let's calculate at which temperature this breaks even and there is no heat deletion or heat creation! To do that, we first determine the equation: K(breakeven)=[J(water)/g(water)]/HC(water). At the break even point, the input energy is equal to the output energy, so J(water)= J(oxygen+hydrogen). Output energy is always 398,480. All the other variables we already know, so: (398,480J/1000g)/4.179HC)=95.35°K or -177.797°C. Which is impossible of course as you can't pump in ice. Meaning you'll always have heat deletion and never heat creation with electrolyzing. So the advice is simply always using the hottest water you have for electrolyzing. Yes, even I was not expecting this.