Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

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macdjord
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Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by macdjord »

TL;DR
Since 2.0.7, 1 water turns into 10 steam, meaning boilers and heat exchangers use 1/10th as much water now, but the amount of water they store has not been updated to match; it should be.

What?
Reduce the amount of water boilers and heat exchangers can contain from 200 to 20.
Why?
Since boilers and heat exchangers cannot be controlled using circuit networks, there are only three ways to disable them:
  1. Cut off their supply of fuel or heat
  2. Cut off their water input
  3. Cut off their steam output
Option 1 has never been very viable; it doesn't work at all for heat exchangers, and even for boilers it is complicated to implement since, without a circuit connection, there is no way to check how much if any fuel a boiler already holds.

Prior to the steam rework, options 2 and 3 were ~equally viable. A boiler or heat exchanger had equal storage for steam and water (200 units of each) and consumed/produced them at equal rates (60/s for boilers, 103.1/s for heat exchangers); thus cutting off either one would cause the device to shut down promptly (in 3.33s for boilers, <2s for heat exchangers).

Now, however, the water consumption is 1/10th what it used to be, but the amount of water each device can store is unchanged. A boiler cut off from water supply can thus continue to run for over 33s, while a heat exchanger can do so for nearly 20s, effectively making this method of controlling them nonviable.

These devices should have their water storage capacities reduced to restore the old balance and make this method of control viable again.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by angramania »

And why this "balance" should exist in the first place? If for some weird reason you need to shutdown your boilers then use 3rd option. And let everyone else to have half minute to change water supply configuration without brownout.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by Hurkyl »

"Weird" reason? I understand this to be a relatively common mid-game thing to keep a legacy steam plant around for backup power. For example, wanting to prioritize accumulators when using solar power, or to have an emergency backup that should only run if you accidentally brick your nuclear plant.


I've never used it myself, but I've heard a number of people describe "disable the offshore pump" as their favorite method of disabling a steam power plant. Blocking the steam output sounds like it's much more intrusive on your design; e.g. you can't use that at all with the most common early game power plant design.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by mmmPI »

4rth method : use a power switch
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by computeraddict »

mmmPI wrote: Fri Mar 27, 2026 8:15 am 4rth method : use a power switch
Method 2 doesn't require any rewiring of the existing plant
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by mmmPI »

computeraddict wrote: Fri Mar 27, 2026 12:32 pm
mmmPI wrote: Fri Mar 27, 2026 8:15 am 4rth method : use a power switch
Method 2 doesn't require any rewiring of the existing plant
Correct, but as mentionned in OP, given the change in consumption for the fluid, it now has quite the latency whereas the power switch is more reactive, the fastest method of the 4 i think.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by macdjord »

The specific use-case that prompted me to notice this problem is in my nuclear plant. I have a large steam buffer in my design, and when the reactors don't have any fuel in them, I like to shut off my heat exchangers and run off the tanked steam exclusively. This way, the heat exchangers remain at 500+ degrees, and so they can all start producing new steam at full output as soon as the steam buffer runs low and another set of fuel cells are inserted. If I didn't do this, then the whole system would keep cooling down until all heat exchangers were at exactly 500 degrees; if demand then suddenly spiked, the steam buffer might run dry entirely before enough heat exchangers had heated up enough to keep up with demand.

In the 1.0 version of the reactor, the steam storage and transport system required many pumps to keep up with the required flow rate. Thus the natural way to shut off the heat exchangers was simply to use circuit logic to shut off the pumps on the steam pipes at the end of each row of heat exchangers and let them back up on steam, which would take ~3.5s (each heat exchanger could hold 200 units itself, plus there were 3 units of piping per heat exchanger in the output pipe, but two columns of heat exchangers would share the same output pipe).

With the new fluid mechanics in 2.0, I initially thought I could do away with pumps altogether and have the heat exchangers, steam buffer tanks, and turbines all in a single fluid box. This would have made things simpler, and also meant that no power was required to get steam from the exchangers to the turbines, making the system less susceptible to brownouts and less dependent on external power during cold-starts. However, this meant I needed a different way to cut off steam production between reactor heats. I thought I had a simple solution to that: disable the offshore pumps feeding water into the heat exchanger columns. However, much to my annoyance, I discovered the change in steam-to-water mechanics meant that the heat exchangers would continue to run for ~20s instead of 3.5s now, which was more than long enough for the heat exchangers to remove a large portion of the heat reserve from the system before they ran dry.

mmmPI wrote: Fri Mar 27, 2026 8:15 am 4rth method : use a power switch
That doesn't stop steam production; it stops steam consumption.

mmmPI wrote: Fri Mar 27, 2026 1:16 pm Correct, but as mentionned in OP, given the change in consumption for the fluid, it now has quite the latency whereas the power switch is more reactive, the fastest method of the 4 i think.
Currently, the method with the least latency is cutting off the steam output, since you only need to fill up the boilers/heat exchangers and the pipes between them and the pump. Using a power switch is slower because, even if you don't have a deliberate steam buffer, you still need to fill up all the generators/turbines (each of which can itself hold 200 steam), and any pipes within the generator columns or between there and the steam producers.

If water consumption worked the way it used to, or the fluid boxes of the steam producers were reworked to compensate, then that would become the fastest method, since you'd only have to drain the fluid boxes of the steam producers themselves, whereas when you're working with the steam outputs you're going to have at least 3 segments of pipe per boiler/heat exchanger.

(Of course the fastest method of all would be disabling the boilers/heat exchangers directly via circuit control, but making that possible is a separate request.)
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by angramania »

I do not see what problem do you have with stopping steam. Let all heat exchangers output to single pipe. Add pumps(one per 11 heat exchangers) to it. After pumps put another single pipe connected to all tanks and turbines. It will work even faster than stopping water flow because steam takes 10 times space in pipes.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by Tertius »

If your use case is the nuclear power plant, here is proof it's not necessary to change fluidbox sizes or to enable temperature reading of heat exchangers or heat pipes to get fast and exact responses. Approach: keep fluid boxes full instead keeping them empty. If the standard state is full, any change to not full is immediate, and the actual size doesn't matter.

Consider this physical setup.
Heat: Nuclear reactor connects to heat pipes connects to heat exchangers.
Water: connects to heat exchangers.
Steam: heat exchangers connect to pumps. Pumps output to steam turbines+storage tanks for steam buffer.

We read these values:
  • temperature T and fuel from 1 reactor (all reactors are connected, so this 1 is representative for the whole reactor line)
  • fill state (steam) from 1 storage tank (all storage tanks are connected, so this 1 is representative for the whole steam buffer)
Minimum temperature:
The reactor has a temperature goal. Its temperature must be at least so the coolest (most far away) heat exchanger is still above 500°C at full load with full output of 103.2/s. This is a layout specific value, and for the setup I built this is 750°C, determined empirically. A fuel cell is inserted into all reactors, if T<750°C and no fuel cell yet present. This way the minimum power plant temperature (reactors+heat exchangers) is ensured.

Steam valve:
There is a valve (pumps) between heat exchangers and steam turbines+steam buffer. As default, it's closed.

To work as a power plant, steam turbines need steam, so if the steam buffer reading is below 200, pumps open to get a minimum amount of steam to the turbines. Not enough for full power but enough to provide about 70% of the reactor maximum. This holds back steam in the heat exchangers and make them heat up, and so do the reactors.

When the reactor temperature reaches the temperature goal of 750°C, the pumps open until the steam buffer reading is 1000. At 1000, it's empirically determined that this is enough to provide each turbine with enough steam to produce 100% of its power output. The plant reached full power production.

When power consumption is below 100%, less steam is being consumed than it's possible to produce. But since the pumps only open if the buffer is below 1000, steam will buffer up in the heat exchangers, making them heat up and so does the reactor. The reactor temperature raises, while the steam buffer stays at 1000.

Now 2 things can happen.
  1. The fuel cell may run out. In this case, the reactor will not heat up any more but starts to cool down. As soon as the temperature falls below the goal, a new fuel cell is being inserted and the cycle starts again.
  2. The reactor temperature reaches an upper limit. I defined a limit of 950°C. If this limit is exceeded, the pumps open. Steam is moved from the heat exchangers to the steam buffer at maximum throughput, so all heat exchangers work fully and pull as much heat from the reactor as it is being produced by the fuel cells. So the reactor temperature stays at 950°C.

    Now again 2 things can happen.
    1. The fuel cell may run out. In this case, the reactor will not heat up any more but starts to cool down. As soon as the temperature falls below the upper limit, the valve closes and the steam buffer is being consumed until it gets below 1000. This is state 1 above. The steam buffer is at minimum and it's being fed by the temperature control behavior from 750°C-950°C. Eventually the temperature gets below the goal, a new fuel cell is being inserted, and the cycle start again.
    2. The steam buffer gets full, so steam valve throughput lowers, so the reactor temperature raises again. If it reaches 1000°C heat is wasted. Eventually the fuel cell runs out and the cycle starts again with state A. This will happen if power consumption is very low (below ~10%) and/or the steam buffer is small.
And that's all. The crucial thing is opening the pumps permanently above 950°C, and you will see an immediate reaction on the reactor temperature. It suddenly stops raising and will not raise above ~960°C (until the buffer gets full). No need to change anything with any fluidbox size.
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Re: Rebalance Boiler & Heat Exchanger Fluid Volumes to Account for New Water-to-Steam Mechanics

Post by mmmPI »

macdjord wrote: Mon Mar 30, 2026 3:07 am With the new fluid mechanics in 2.0, I initially thought I could do away with pumps altogether and have the heat exchangers, steam buffer tanks, and turbines all in a single fluid box.
You can on Nauvis if you use a power switch i feel (depending on your definitons). Since you can now read the temperature of the nuclear reactor, you can make sure it never gets under a certain temperature , you refuel it when temperature is under 700°C UNLESS your steam buffer is above 50 % for example with a decider combinator reading both temperature and steam buffer, and only allowing output when steam AND temperature ( and burning fuel) are low.

All in 1 fluidbox, no pumps. It reacts in 1 tick when the power switch open or close. Heat exchanger turn off when steam buffer is full while the switch if off. Maybe the temperature will drop under 700°C in that time, but only if there a steam buffer, already shared with turbines so it is super reactive, worst case is you ramp up consumption when the temperature is 500°C, and you need to make sure that threshold of 50% of the steam buffer last long enough for new steam to be generated. ( you can math the required size of steam buffer or choose a different %, or determined empirically).

The decider logic is the same kind of thing i would use on a space platform to make sure there is no brownouts.

It is easier to set up for boilers than for heat exchanger because then the power switch stops both consumption and production if you use a single fluidbox and no pump after the boilers and before the steam engines, this is what i would do for the legacy steam engine when i upgrade to solar. I used to wire the offshore pump as you mentionned, and noticed it wasn't as good anymore so power switch is my new go-to when my stuff is small enough that i can avoid pumps. When it gets bigger it can get messy with the poles and you may be required to use pumps due to size anyway, then wired pumps it is for me.
macdjord wrote: Mon Mar 30, 2026 3:07 am (Of course the fastest method of all would be disabling the boilers/heat exchangers directly via circuit control, but making that possible is a separate request.)
I don't think it would be faster it think it would be the same, 1 tick, given how i would use a power switch, and that water or steam "teleport" even to the further away turbine/steam engine now. But even though i don't share the reasonning , i don't mind the aim of the suggestion. I understand both your suggestion and the one you linked aimed at making things a bit easier, i feel allowing player to read the temperature on the nuclear reactor was a bit of a similar move and i like connecting stuff the with the circuit network. I feel it doesn't remove the puzzle, you can still use the other methods ( even the method 4 :D ). Here the morre the better for me :) . I tend to share the observation that wiring the offshore pump was easy and effective before and it isn't the case anymore now. Overall i don't mind both suggestions. I just wanted to mention the power switch as a viable method (imo) when you are not in space.
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