Factorio Forums

For the longest time, I believed that steam engines can only extract energy from steam of at most 165°C, because this is what "max temperature: 165°C" generally means. However, if you provide steam from heat exchangers to steam engines, they will happily make use of the full energy in the steam, provided that you trick the fluid system into not providing full flow into a steam engine. Then you can reach states like this: How to reproduce
Load the savegame I provided for the other issue over here: viewtopic.php?f=47&t=97361
Apparently the fluid update logic makes it a bit unpredictable which steam engines will immediately get preferential steam flow.

Suggestion
Change the tooltip to make clear that 165°C is the optimal or ideal working temperature, since this is the temperature at which the steam engine will reach full output power at full input steam flow.
Alternatively, implement an internal cap or filter for the temperature, so that steam of temperatures >165°C is reduced to 165°C in its energy content. Then, the tooltip would become indeed correct.

it seems like a localisation issue.

Should say minimum temperature, not maximum.

ptx0 wrote: ↑

Sun Mar 28, 2021 5:49 pm

it seems like a localisation issue.

Should say minimum temperature, not maximum.

Except it's not a minimum temperature. They work perfectly fine with lower temperature steam, except the obvious lower power output at max fluid use.

Silari wrote: ↑

Sun Mar 28, 2021 5:55 pm

They work perfectly fine with lower temperature steam

there is no lower temperature steam.

It isn't that they can't use higher temperature steam, it is that they waste the energy of the steam. 500 degree steam can produce more energy per unit than 165 degree steam.

From the wiki: https://wiki.factorio.com/Steam "The energy storage of steam is exactly 200 Joule / unit / degree Celsius." Steam engines just don't take advantage of the higher temperature.

NotRexButCaesar wrote: ↑

Sun Mar 28, 2021 9:29 pm

It isn't that they can't use higher temperature steam, it is that they waste the energy of the steam. 500 degree steam can produce more energy per unit than 165 degree steam.

From the wiki: https://wiki.factorio.com/Steam "The energy storage of steam is exactly 200 Joule / unit / degree Celsius." Steam engines just don't take advantage of the higher temperature.

My screenshot proves this statement is not true: steam engines can extract the energy from the entire energy scale, but the input flow rate of the steam will be wasted if you fill in too much steam. The only upper limit is the total output power. You can increase temperature and reduce input flow rate and still reach maximum power output. What you cannot do is reduce temperature and increase input flow rate, because the tooltip about maximum input flow rate is actually correct.

ptx0 wrote: ↑

Sun Mar 28, 2021 6:04 pm

Silari wrote: ↑

Sun Mar 28, 2021 5:55 pm

They work perfectly fine with lower temperature steam

there is no lower temperature steam.

Not sure why you think that, but the game disagrees with you. Fluids can have different temps, including steam. Sometimes their max temp is the same as their default temp, like lubricant, but they all allow it. Pretty sure it's been like that since steam was made it's own fluid, at least.

Silari wrote: ↑

Mon Mar 29, 2021 1:11 am

ptx0 wrote: ↑

Sun Mar 28, 2021 6:04 pm

Silari wrote: ↑

Sun Mar 28, 2021 5:55 pm

They work perfectly fine with lower temperature steam

there is no lower temperature steam.

Not sure why you think that, but the game disagrees with you. Fluids can have different temps, including steam. lowertempsteam.jpg

Sometimes their max temp is the same as their default temp, like lubricant, but they all allow it. Pretty sure it's been like that since steam was made it's own fluid, at least.

not in vanilla.

ptx0 wrote: ↑

Mon Mar 29, 2021 1:48 am

not in vanilla.

Just because the vanilla freeplay has no way of producing steam at temperatures below 165°C does not mean that the infinity pipe from /editor mode cannot make steam at 110°C. In fact, the tooltip for vanilla steam says the minimum temperature for steam is 15°C, which is why the energy in one unit of steam is actually
(165°C-15°C)*200J/°C = 30kJ

ptx0 wrote: ↑

Sun Mar 28, 2021 6:04 pm

there is no lower temperature steam.

I can’t test it right now, but shouldn’t it work the same with steam turbines? They are the same prototype as steam engines. For them exists a lower temperature steam even in vanilla.

I think it means:
Steam Engine can use steam with termperature up to 165 degree.

valneq wrote: ↑

Mon Mar 29, 2021 1:54 am

ptx0 wrote: ↑

Mon Mar 29, 2021 1:48 am

not in vanilla.

Just because the vanilla freeplay has no way

i'm just gonna stop you there and agree with you on that... just because freeplay is the recommended way to play the game, and the editor has a number of differences that would make the freeplay descriptions appear incorrect.

ptx0 wrote: ↑

Tue Mar 30, 2021 4:40 pm

i'm just gonna stop you there and agree with you on that... just because freeplay is the recommended way to play the game, and the editor has a number of differences that would make the freeplay descriptions appear incorrect.

This starts to go off topic. The issue I describe in the original post is entirely a vanilla freeplay issue.
Steam at 500°C is readily available, just as is the steam engine.

seems like changing it at this point is going to result in confusing inconsistencies in different translations.

valneq wrote: ↑

Sun Mar 28, 2021 1:39 pm

However, if you provide steam from heat exchangers to steam engines, they will happily make use of the full energy in the steam, provided that you trick the fluid system into not providing full flow into a steam engine

That somewhat makes sense to me ... tiny amount of too hot steam would mix with colder air, creating colder steam&air mixture with the same energy potential as before, maybe?
Anyway, message of the tooltip is ... steam engines is not supposed to be connected to heat exchangers. And if somebody does, and figures out how to limit the flow such that the steam engine uses full energy potential of the 500°, I'd say good on them. If someone wants to document it on wiki, so be it, but in-game tooltip should be simple, imo.

posila wrote: ↑

Wed Mar 31, 2021 10:19 am

Anyway, message of the tooltip is ... steam engines is not supposed to be connected to heat exchangers. And if somebody does, and figures out how to limit the flow such that the steam engine uses full energy potential of the 500°, I'd say good on them. If someone wants to document it on wiki, so be it, but in-game tooltip should be simple, imo.

So "not a bug"?

As I said, the issue is more confusing with modded entities, such as bob's boilers and steam engines.
Any chance there will be a change in internal logic so the output power will be
flow_rate * (min(temp, max_temp) – min_temp) * heat_capacity
rather than
flow_rate * (temp – min_temp) * heat_capacity
?