Debug mode Energy calculation

[adelfaidah]

Hey everyone, 

I am using debug mode and just checking on calculations for the sake of confirming for myself which processes delete heat and which dont.

I realised either something is off in the calculations of the debug mode or I'm missing something. I placed a 200kg 20C sandstone tile in a vacuum and selected it via debug mode as can be seem in the screen shot below. The debug mode says that it contains 234.5 kJ per kg which when I do the calculation my self (Specific heat * temperature in kelvin * mass) It matches it just fine.

However, the total joules is displayed as 56.28 MJ, which essentially should be simply obtained by multiplying the 234.5 kJ/kg by 200 kg. But that gives me 46.90 MJ which doesnt match at all. Any ideas to what am I getting wrong here?

[wachunga]

So the tile you are experimenting with is comprised of a solid cell of 200kg sandstone with a tile building in front of it. In ONI, buildings have 1/5 of the thermal mass they "should" (mass * specific heat). The selection tool is adding up the solid cell and this "facade" building for the total joules, which is 1.2x what you are expecting (the building adds the 0.2x).

In practice, this tile building has zero mass and heat is conserved properly when interacting with other cells of gas/liquid/solid. Most of the time. For some things which are this cell/building hybrid, the building portion adds mass erroneously. Farm tiles are one example, they are 100kg in mass but behave as 120kg. There are others which I forget offhand, there was a thread about this years ago, good luck finding it.

Do something like this in your experimenting to see how heat is or isn't conserved properly:

 

The top cells/tile are at 20C, the bottom shows what happens when a equivalent mass cell of 220C is placed next to them. Equilibrium should be 120C, which it is for the tile and the regular cell (heat transfer stops once the delta reaches 1C, so really 119.5 and 120.5). The farm tile on the other hand equalizes at ~111C, which shows the farm tile is 20% more massive then it should be. Increase the adjacent cell to 120kg and you get 120C as expected (or extremely close, there is some tiny error).

The rightmost and highlighted tile shows what happens when you replace the 200kg background cell with a vanishingly small amount of gas. The selection tool shows joules per kilogram for the gas, but total joules of the building. After one tick, the gas evaporates into vacuum and no heat transfer occurs because there is nothing for the adjacent cell to interact with.

[adelfaidah]

Thank you so much for the response this was really helpful!