coffee-factorio wrote: Mon Jun 30, 2025 12:54 am
You have this thing running in a test environment under high draw. If I graphed the temperature it'd look like a wave with a peak and a valley.
There's going to be a time period where (t-750) < 0. The inserters needs to swing. This takes less than a second to perform fuel load but it gets you thinking about what the actual issue might be: The reactors need to reheat the system, which is going to be difficult under high draw or worst case test conditions.
During that latency period bots will reload the logistics chests in an arbitrary order, which will see the chests overloaded or misloaded. Faster bots will compound the issue. Ultimate cause is high power draw, since the amount of heat added to the system will be T_added - T_removed. It'd be hard to replicate because everything has to fail perfectly, depending on how much power you pull from the system reactors might heat everything fast enough that it'd never be an issue. If bots are "slow enough" it's not relevant either... granted; bots are never fast enough so that isn't saying anything.
I don't see how "slow bots" can cause an issue here, because they have 200 seconds time to refill 4 chests. If they aren't able to do that in time, you need to improve your logistics. If there are not enough fuel cells, you need to improve your fuel cell production. Also you need to transport away your used up fuel cells and provide enough capacity to recycle them. All this is no issue with the reactor setup. The fast inserters will insert the cells in 1 swing, which takes 0.208s, and they're always available.
About power draw: as long as you're not having full load of 480 GW, which is the case for probably 99.5% of all the time, the 4 reactors will produce 480 GW heat, the 48 heat exchangers will convert 480 GW heat to steam, and the power being consumed is less than 480 GW, so more steam is produced than consumed. First all the integrated buffers in turbines and steam buffers will fill, and if they're full no more heat is consumed. In this moment the heat exchangers will heat up, and the reactors too. Heating up under power draw is a slow process, the more power is consumed the slower it is, but it happens. So the temperature will eventually rise above the threshold. It will also rise to the threshold if full 480 GW is pulled, because if the temperature is lower than required to heat up the farthest heat exchanger to 500°C, that heat exchanger will not work, so just 470 GW is being produced, so the reactor will heat up, and eventually all heat exchangers are at least 500°C.
In this setup, with 4 reactors and this heat exchanger layout, the minimum reactor temperature to operate with full power, is about 580°C (I tested). So to have a bigger heat buffer for extremely low power situations, you can set our threshold to 600°C (value T=-600 in constant combinator), not 750. If you run the power plant that way, and you pull 400-450 GW, you will see the temperature will rise to about 602°C but not much higher during one fuel cell burning phase. If the cell is burnt up, temperature will drop almost immediately (just a fraction of a second), and the next cell is being inserted. This is a delay of about 1/3-1/4 second, including the inserter swing. This time there is no cell burning, so the power that could be generated during that time is not produced, so this is what the whole plant will produce less than 480 GW. If this is 1/3s or 0.33 seconds, it's 0.33s/200s = 0.00166 or 0.166% of a burning period of 200s. So there's 0.00166 * 480 GW = 0.8 GW power missing during that period, and the whole plant is effectively producing 479.2 GW instead of 480 GW. As long as your draw is below 479.2 GW, your reactors will always heat up, and as long as you set the threshold to ~600°C or above, the plant will be able to continuously provide that power since the heat exchangers will not cool down to 500°C and stop working.
The reactors will not go below 580°C (the threshold where the farthest heat exchanger will not get enough heat under full power draw and stop working) while the next fuel cell is being inserted - the insertion is fast enough.
The 4 reactors are always within a temperature corridor no bigger than about 3°C. No reactor will be more than 3°C hotter or cooler than one of the others. They're directly connected next to each other, and the setup is symmetric and homogeneous. So there's really no need to read more than 1 reactor.
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