Need help with heat capacity calculations.

[MustardWarrior]

What I want to do is dig a big pool of oil down to the abyssalite, then dig the abyssalite down to where it just barely doesn't let out the magma, then build an insulated tile box around the magma pocket dig out the abyssalite, exposing the magma, then run out and immediately seal up the insulated tile box.  Then leave it there for however many cylces it takes, wait for it all to turn into petroleum, then come back and crack it open when it's done.

So what I want to do is scroll over some of  the oil tiles and magma tiles in the neutronium pocket, guestimate an average temperature and density (kg/tile), count the number of magma tiles, adjust the size of the insulation box so that I get the right number of oil tiles, so that I can do this without overcooking the petroleum too much though I will probably overcook it a little just to leave a margin of error.

So I tried testing this out in debug mode.  I built an insulated tile box using insulation to test the heat capacity numbers since insulation has 0 conductivity.

So I figured just to be safe I'd use the heat capacity of sour gas since it is higher than crude oil or petroluem, that way I would definitely get over 420 celsius I was targeting.

So the specific heat capacity is 1.9 for sour gas vs 1 for magma  and 1 for igneous too 

So I set the density to 1840 kg/tile for magma and 870kg/tile for crude oil which seems like it approximates a standard non pressurized oil density and standard magma density. 

I set the crude oil to 80 degrees Celsius and the magma to 1560 degrees Celsius.

I then calculated that crude oil is 340 degrees away from the desired temperature while the magma is 1140 degrees away.

So I calculated 1140*1840*1 for the magma for the amount of heat given off per tile and 870*1.9*340 for the amount of heat absorbed per tile.  Since insulation has a thermal conductivity of 0 I expected this to work out to:  (1140*1840*1)/(870*1.9*340)  = 3.73 or every tile of magma is going to give off 3.73 times as much heat as the oil tiles would absorb in this situation so I round down to 3.5 to err on the side of caution. And I build 20 tiles of magma and 70 tiles of crude oil the crude on top of the magma in a 10 wide by 9 tall box (that is the size, not included any walls) in debug mode and...

Not even close.   What am I doing wrong and how do I do it right?

[simonchvz]

8 hours ago, MustardWarrior said:

So the specific heat capacity is 1.9 for sour gas vs 1 for magma  and 1 for igneous too 

Are you looking at the thermal conductivity for magma instead of the specific heat?  I'm not at my PC, but one of my (admittedly old) reference sheets has the specific heat of magma at .2 and thermal conductivity at 1.  That would put your numbers off by a factor of 5, assuming the sour gas numbers aren't similarly off.  Otherwise the logic looks correct.

As an aside:

8 hours ago, MustardWarrior said:

Since insulation has a thermal conductivity of 0

This isn't strictly true, it's just a very small number that rounds to zero in display.  Insulated tiles will transfer heat very slowly.  Adjacent tempshifts will exacerbate this pretty dramatically.  Didn't sound like it would be particularly relevant to your question, but just in case...

[Angpaur]

If your target temperature is 420C and you want to use 1840kg magma then I hope that this will help:

http://www.oni-heat-calc.cba.pl/?mt1=liquids&mt2=liquids&m1=Crude%20Oil&m2=Magma&t1=80&t2=1560&mm1=3650&mm2=1840&st=0

[SakuraKoi]

After doing another way to calculate (which did also math the factor of ~2 of the tool), I can not help but ask how it is "not even close" since it should be and after doing some other math, I arrived at the this conclusion: Someday it should be and the day would not be this week even if you play at top speed without pause .

So how long did you wait?

After all, thermal conductivity is rather low since at best you move the required shift of

41 952 000 000 DTU (36 800 000 g Magma times 1140 temperature difference in an unit that is not Fahrenheit times 1 SHC)

at the very best at a rate of 26 600 DTU per second. I.e at best you need 1 577 142 seconds or 2682 cycles.

 

The rate is indeed from the best case scenario: Igneous Rock with Crude Oil = 2 DTU per °C difference per tile =>2*(1410-80)*10 =>26 600 DTU transfer.

I'm not quite sure since I have read that transfer rates of different states to different states but even then, I doubt you'd have less than a tenth of that without even considering the speed drop off (which I suppose increases the time many fold). Unless you maybe at refined metal tiles in between (not quite sure if the transfer rate is 16 times better then)

Problem of course also is that you do have much oil that transfers heat with oil of a much lower temperature, so while what is cooked by the magma is somehow hot, decreasing the rate of transfer, oil and oil are not that far apart.

tl;dr I am afraid you simply had too much mass in your experiment. Also one magma tile between two metal tiles and oil tiles beyond should be the best way I'd say. Might as well do a small experiment later...

[MustardWarrior]

Okay so I may have found the culprit and the math might work after all.  Okay so I put the crude oil on top of the magma and at very beginning it goes crazy as the magma tries to float to the surface and apparently it will destroy energy during this process.  I'm not sure where the saves are located but it's as I described a 10x7 tile crude oil on top of a 10x2 magma with the aforementioned mass and temps.  It's cycle 11 Most of the crude oil is at like 330 degrees C and there's only 1 tile of sour gas that is about 1039 kg that is at like 473 degrees C  and everything else, all of the rock is well below 400 mostly in the mid 300's.  I did it the other way around with the magma on top and it actually looks like it's going to work, I started that one a few cycles after.  The rock formed a coherent wall unlike in the previous example where bits of rock float halfway up the box before hardening, leaving lots of debris everywhere.

Okay it worked, with heat to spare and in only about 15 cycles.  So basically what this shows is that magma is less dense than oil and when it tries to float to the surface it can destroy heat.  I think my scenario is pretty close to a worst case scenario and it only brought the oil about 75% of the way from 80C to 420C.  Okay good now I can be more confident in my calculations and I feel like a science man.  Edit: just to avoid confusion I started the one on the right a few cycles later.