Factorio Forums

there something odd in temperature distribution when a storage tank is in a circuit

it looks like temperature is carried along with the fluid flow, so that if you have a downpipe at a lower temperature but the previous pipes are full at 10.0 water there is no more heat exchange as no fluid returns backward

test case:



here I attached a tank after the engines. the tank filled up, raising temp while filling. at full, it was at 41 deg (and boiler were no longer heating water)

the bug is, dropping water at 100 deg in the tank made the water magically become 27 deg, then temperature raised up while filling

but there is more:



I attached a tank on the other end (before the boilers)

the second tank filled up, reaching an equilibrium of 35 deg.

the first tank, which provide some water to fill up the second tank, raised its temperature to 47 deg

so, looks like boiler only heat passing water, and if there is no flow, heat doesn't circulate trough the pipe.


note that when attaching the second tank, heat circulated 'backward' from the boiler. so if heat transmission is ever implemented, boiler would also heat backward to the nearest pump

Good analysis. The temperature is at the moment indeed exchanged only when there is a flow of fluid. This is a simplification in design we have done a long time ago. This might be revisited in the future (especially if we go for more realistic energy production circuits). For now it goes to not a bug.

Yeah but what about the other thing?

Not the flow: the fact that 100deg water enters in reservoir at 27deg?

LoSboccacc wrote:Not the flow: the fact that 100deg water enters in reservoir at 27deg?

As I understand this is solved arithmetically (Although only the devs know the real answer)

If you have 100 units water stored at 27 deg and eg 10 units of hot water at 100 deg are added, the whole stored water ends with 110 units with (100*27+10*100)/(100+10)= 33.64 deg

The first drop may have been the result of some units of cold water between boilers and tank in the first place? And yes, the fluid simulation seems to be very simplified and buggy sometimes, hence as the "steam engine" is using up water instead of just cooling down overheated steam to hot water.

I attached a brand new empty tank to a pipe holding 100deg water.

No averaging there should have happened

Does it happen again when you deconstruct the tank and rebuild it?

Connecting the storage tank makes the flow faster. Faster flow means that the boilers have less time to heat the water. Therefore the water becomes less warm. Combined with the fact that the temperature is exchanged only when water is flowing this will lead to cases when storage tank connected to the output of boilers will never reach 100 degrees. I tried to connect the storage tank after a line of boilers and that is exactly what happens:

- water remaining in pipes with 100degrees goes in
- the fluid columns are equalizing here the less than 100degrees water goes in
- the fluid columns get closer, the fluid slows down, the water is heated to 100degrees again

This can be really confusing, I agree. So while it is not really a bug per se we will fix it. But not for 0.9.x - hence I put it to known issues so it doesn't get lost

This style of boiler is no longer in the game, so this issue no longer occurs