niahoo

Ice box of polluted water keeps producing 5kg of water

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niahoo    1

At first I thought because I had too many polluted water in  the box. I still worked as when the aquatuner was running, there was enough pipe length to make room for the water to go out the veen. But suddenly 5kg of water appeared here. it was very annoying because that additional 5kg made the vent overpressured even with the full pipe running, which blocked the pump pipe, so no more cooling.

I reloaded and managed to watch the moment where the water appears, but I have no clue about what is going on. Maybe its some of the steam ? Steam pressure is 103kg/tile. Maybe polluted water went to cold and  froze (but that would produce polluted ice anyway, isn't it?)  In the screenshot there is now 10kg, but I dont know if 5kg appeared twice or 10kg in one shot.

So I just emptied it all, and refilled with just 60kg on the top tiles. So this time it still works. I set the thermo sensor to 1°C so no ice block (though I made the whole box go to -4 and couldn't freeze the water to just dig it out :( )

The worst  is that I cannot filter it out because the pump does not pull water from that tile space ...

So, any idea of why there is water here ?

Thank you  for reading :)

 

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mathmanican    3379

5kg seems like a partial evaporation event. I'm guessing one of the tiles touching your pw pool got too hot and caused the pw to partially evaporate into steam and then condense back to water.

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TripLykely    43
41 minutes ago, mathmanican said:

5kg seems like a partial evaporation event. I'm guessing one of the tiles touching your pw pool got too hot and caused the pw to partially evaporate into steam and then condense back to water.

That’s what it looks like to me; the room with the steam turbines can exchange heat with the polluted water through the joint plate which is where the water is appearing.

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niahoo    1

Hey thanks :)

That could be but the temperature is very cool since I added solar panels to the power grid. Plus it would have either evaporated a full water tile, which is unlikely, or maybe the content of the pipe that runs with 10kg, but it is an insulated pipe. I know such pipes can exchange heat but no way it could let pwater between 1°C and 7°C turn to 120°C in an instant, right ?

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edit: I missed the "partial" word, that is a thing. I looked it up and found your post

I struggle to find where the heat comes from. I can't believe that the bottom adjacent insulated tile would go above 50°C.

Anyway I should just remove the icebox altogether,  I do not like it very much as it is slow to cool down the forge when all the smelters are smelting.

Edited by niahoo

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kbn    286
5 hours ago, niahoo said:

I struggle to find where the heat comes from.

I think the flaking is caused by the Abyssalite tile on the right.

According to the wiki, the heat transfer efficiency of gas to solid is 25 times higher than that of liquid to solid.
The hot steam heats the abyssalite tiles slowly, but the cold pw does not cool the abyssalite tiles.
As a result, the abyssalite tiles slowly heat up, and when the boiling point temperature of pw is exceeded, it is presumed that flaking occurred.

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niahoo    1

Oh, that is a good explaination if it is true, but I was believing that abyssalite natural tiles had no heat conductivity ?

So, if I follow you, it means that the abyssalite heats my water all the time, and that my aquatuner is kind of heating the same  water it is cooling ...  So if I let a tile of CO2 between the ice box and the abyssalite, it would solve my flaking problem and in the same time save some power ? I'll  try that.

Thank you all.

Edited by niahoo
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blakemw    48
16 hours ago, niahoo said:

Oh, that is a good explaination if it is true, but I was believing that abyssalite natural tiles had no heat conductivity ?

 

This is a common misconception because in the game the thermal conductivity of abyssalite is rounded to 0, but it's actually 0.00001. In fact abyssalite usually conducts more heat than insulated tiles, usually about 2-30x as much depending on the insulation material and exact elements involved. (in particular, Insulated Tiles are much betterer at dealing with high conductivity gases, they are still better when dealing with low conductivity gases but the disparity is smaller)

The game does not perform heat transfers which it considers too small to be significant, so for example there is usually truly zero heat transfer between two abyssalite tiles, or two insulated tiles. There also may be zero heat transfer between an insulated tile and solid or liquid (putting aside flaking) but it is very peculiar to the exact materials and temperature delta involved. Gas will nearly always exchange heat with Insulated Tiles (unless they are made of Insulation) if there is a significant temperature delta, and hydrogen and steam are particularly prone to causing issues as they have very high thermal conductivity for gases.

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wachunga    448
9 hours ago, blakemw said:

There also may be zero heat transfer between an insulated tile and solid or liquid (putting aside flaking) but it is very peculiar to the exact materials and temperature delta involved.

The magic delta for insulated igneous tiles is very easy to remember at ~10C. Below that and insulated igneous will transfer no heat at all with gases. From there you can derive the values for solids or liquids or other insulated materials. ~250C delta for a solid or liquid. Insulated ceramic is ~27C and ~677C respectively. Insulated obsidian is ~2C and ~50C. Actual numbers are slightly less with igneous being 9.something, but I can never remember exactly.

Edited by wachunga
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blakemw    48
12 hours ago, wachunga said:

The magic delta for insulated igneous tiles is very easy to remember at ~10C. Below that and insulated igneous will transfer no heat at all with gases. From there you can derive the values for solids or liquids or other insulated materials. ~250C delta for a solid or liquid. Insulated ceramic is ~27C and ~677C respectively. Insulated obsidian is ~2C and ~50C. Actual numbers are slightly less with igneous being 9.something, but I can never remember exactly.

This would actually be a useful thing to have on the wiki, if no-one beats me to it I'll derive the exact formula for the magic delta (which should be pretty simple) and make a chart for every relevant material.

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wachunga    448

For insulated igneous interacting with a solid or liquid, the precise delta is 248.0507C. Below that no heat exchange. Running the math, that delta would cause a 1/65,536 change in temperature of the igneous. I imagine that number jumps out at the computer science folks.

I haven't thoroughly checked all materials to verify how precisely that actually plays out in game. In my usage, I just do rough estimates based off the 10C igneous number by adjusting for a material's SHC and conductivity relative to the reference igneous.

As for wiki know how, I am clueless.

Interacting with thermium should halve all the deltas since it gets an undocumented 2x multiplier. Again not thoroughly verified, but that ought to be the case.

Edited by wachunga

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wachunga    448

Very interesting. Now that I think about it, I can't recall if I ever tested with the insulated tile substantially away from 20C. So probably not.

Good find. 

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psusi    307
1 hour ago, blakemw said:

The fact that the magic delta gets smaller as the insulated tile gets colder, suggests it's because the floating point system can more precisely represent values which are closer to 0.

Definitely not.  Single precision floating point has about 8 decimals to work with, so if you are below 1000K you still have 5 past the decimal place.  Wasn't one of the rules for heat transfer that it has to cause at least a 0.1K change to bother?

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blakemw    48
8 hours ago, psusi said:

Definitely not.  Single precision floating point has about 8 decimals to work with, so if you are below 1000K you still have 5 past the decimal place. 

Well in practice generally a temperature change smaller than 0.0001 K is not observed when the temperatures is in 3 digits. Which is 4 decimal places. So seems like a good starting point for where to limit things to avoid floating point wonkiness. For example, if the tool I'm using is correct (relative to the floating point system ONI uses), a 0.0001 K temperature change to something at around 300 K, can involve substantial inaccuracy, for example 273.15 is represented as 273.149993896484375 and 273.1501 is represented as 273.15008544921875, so what should be a 0.0001 K temperature change is actually 0.0000915 K, 9% error. Clearly this kind of temperature change is at the limit of 32 bit floating point precision and the real question is if the magic delta is a direct and natural consequence of the floating point calculations, or if there is some code which acts as a safeguard against going too deeply into the territory of floating point imprecision - but I'd expect it's the former case.

8 hours ago, psusi said:

Wasn't one of the rules for heat transfer that it has to cause at least a 0.1K change to bother?


I think you're thinking of 0.1 DTU? This can apply with Insulated Tiles, but it's trivially obvious that it's not the mechanism responsible for the magic delta. For example the heat transfer with an Insulated Tile should be identical whether it's made of Igneous Rock or Obsidian since both have identical thermal conductivity, but Igneous Rock has a magic delta 5x greater than Obsidian. So there is a temperature range where the Obsidian Insulated Tile is exchanging heat, but the Igneous Insulated Tile is not. This doesn't make sense in terms of the 0.1 DTU rule since both should exchange exactly the same amount of DTUs if they are the same temperature. In fact, we can determine that at the magic delta for a 20 C Igneous Rock Insulated Tile, an Obsidian Insulated Tile is transferring 8 DTU per tick and the Igneous Rock one should be too.

I have seen it proposed that there is a minimum temperature change, perhaps the value of 0.0001 K, but testing readily shows this is is only the minimum temperature change at 3 digit temperatures. For example close to 0 K, a temperature change such as 0.000004 K can be observed (using Debug mode).

Edited by blakemw

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psusi    307
19 hours ago, blakemw said:

I think you're thinking of 0.1 DTU?

Nope... I believe there was a rule that if say, it is decided to transfer 500 DTU of heat, but that transfer won't change the actual temperature of the target cell by 0.1K ( say, because it has high mass and/or SHC ), then the transfer isn't done.  Or maybe it was if the heat transfer would cause the destination to have a higher temperature than the source?  I don't remember now.

19 hours ago, blakemw said:

it's trivially obvious that it's not the mechanism responsible for the magic delta. For example the heat transfer with an Insulated Tile should be identical whether it's made of Igneous Rock or Obsidian since both have identical thermal conductivity, but Igneous Rock has a magic delta 5x greater than Obsidian.

Right.. that's because of the 5x difference in SHC, so the actual heat energy one holds is 5x less than the other.  Thus the delta T is 5x.

 

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blakemw    48
15 hours ago, psusi said:

Nope... I believe there was a rule that if say, it is decided to transfer 500 DTU of heat, but that transfer won't change the actual temperature of the target cell by 0.1K ( say, because it has high mass and/or SHC ), then the transfer isn't done.  Or maybe it was if the heat transfer would cause the destination to have a higher temperature than the source?  I don't remember now.

There is clearly no such rule because smaller temperature changes are easily observed. If you aren't using Debug mode, then to easily see this you need to take advantage of the fact that the game displays temperatures between 0 and 1 C to 4 decimal places instead of 1 decimal place, then it can be seen that a 0 C tile can increase in temperature to 0.0001 C or whatever. With Debug mode enabled you can use the sample tool to see a high precision temperature for any tile at any temperature.

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