Amount of items to put in a closed loop

[septemberWaves]

I'm wondering if there's a particular way of calculating the most efficient number of items to put in a closed loop (like water barrels for creatures, or bricks for hot air). For systems which need replenishing, like the lamps used in making hydrogen chloride, it's a simple matter of adding a priority inserter. But I'm not sure how to figure out the optimal number of items for a completely closed system. I'd rather avoid just putting everything into the logistic network, so that I don't end up having machines craft vastly more items than are needed and fill up storage.

[error0664]

not sure if i understood your question correctly but i can give you an example how i did make a setup for water barrels / creaturs:

i have a external source of new empty water barrels that is producing until a buffer is reached (eg 1000 empty barrels) that are transported to each creature location

each creature location is requesting 200 empty barrels so there is a buffer of 200 empty barrels (i do this with my train network)
in each of these locations i have a simple (logistic) circuit condition on an inserter that is putting from these 200 empty barrels into a passive provider; condition: filled water barrel < 10 (which is one stack)

so this is putting empty barrels into my system until i have at least 10 filled barrels sitting in the same logistic network (usually more than 10 because transport takes some time which is ok, but it will stop putting more into the network if you not fall below 10)
i have one or many filling stations which simply request empty barrels (requester chest) and fill them with water and put water barrels into passive provider

with no consumers, this makes sure that there are always at least 10 filled barrels in the system sitting at the filling station

then with consumers (eg. auog padd) again simple setup: requester chest requesting water barrels for auog, and when they produced, i use a filter inserter to pick the empty barrels again into provider chests, these empty barrels are transported to my filling stations again

barrels usually go with a completly closed loop
this makes it easy to extend (double auog padd for example) as more empty barrels are sitting in the new auog padds, and if i fall below 10 filled barrels it just puts some more into the system

i do the same with cages, these trigger sometime a refill from my 200 cages buffer since there is a kind of 80% yield at producing auog for example

this worked fine for me until breeding; where there is a yield of >100% for cages due to some productivity is allowed there - so my cages building up over time and i need to get rid of them rather than replenish



for a non logistic setup, for example you have a belt for closed loop bricks (for hot air as an example) I am hand feeding into the loop until all entities along the loop are producing at 100% uptime (you only do this once since you have no loss/gain of bricks)

[fractalman]

To uuse a closed loop and the logistic's system, you put the output-e.g. the empty barrel-into an active provider chest. It will then be taken to either a requester directly or a storage chest, where it will be pulled from before a passive provider

Then, when making the "input"item, e..g. the barrel of water, you put them into a passive provider.

[mathiaszealot]

Personally? Bricks and Barrels are cheap, why are you trying to be efficient with them to save a few hundred?

That said it's an interesting question, the naive approach would just be to have enough in the system to inserter fill every production entity: 40 Auog Paddocks taking 5 water barrels per craft fills to twice capacity, plus one set in operation for 15 barrels each, or 600 water barrels.

This starts to break down under several conditions:
1) Long distance between production and reprocessing areas: If the empty barrels need to return down a single line of 40 Paddocks to reach the Automated Factory you have refilling them, then all the way back down there's a time lag longer than two cycles, meaning you'll need extra barrels to make up for the "in-transport" barrels. This also applies if, for some reason, you're not refilling barrels or cooling hot bricks on site.
2) Insufficient Transport capacity: More a structural design problem, but at some point my single line of Auog paddocks couldn't be supplied by one belt.
3) Insufficient Reprocessing capacity: Likewise, you'll need enough re-processors filling barrels to keep up.

Given that #1 is the only one that causes you to need more barrels, I assert the calculation would be something close to:
(Production_Facilities * Recipe_Quantity * MAX[3, (Transport_Distance / Transport_Speed + Reprocessing_Time )/ Actual_Craft_Time]

Which is, roughly, the Naive assumption of 3 crafts worth of materials per facility, modified upward if the transport and reprocessing time becomes more time consuming than 3 crafts at the production facility. This should probably be calculated per-facility, as a bulk average distance won't be correct. Could calculate the function's discontinuity at 3 craft time's distance and take the average distance beyond that to save a bit of time, though.

[BlueTemplar]

You have to be careful to not to put in too many of them - or the whole system will lock up !

For simple 2-machine setups I use a rule of thumb of "two items worth of production for the main building, one worth for the recycler".

(However, sometimes I still find my cooling towers to lock up for some reason ??)

[fusion_future]

You have to be careful to not to put in too many of them - or the whole system will lock up !

For simple 2-machine setups I use a rule of thumb of "two items worth of production for the main building, one worth for the recycler".

(However, sometimes I still find my cooling towers to lock up for some reason ??)

I found if you put productivity modules in a FTS reactor you actually produce slightly more steam than water that's consumed so the 1:1 balance goes off and eventually your cooling tower loop locks up. After I realized this I then noticed any recipe/building combo that has loops and allows the use of production modules i.e. cages or lamps in hydrogen chloride you actually end up creating extra resources than the loop intended. It seemed a bit like an exploit so I decided to only use speed modules for these types of recipes to stick with the developers intended design.

[BlueTemplar]

Yeah, thanks, I eventually figured this out !
(And set up an overflow system for the excess steam, reheating it in a heat exchanger and then burning it for power.)

Here's hoping for some temperature sensors in the Factorio expansion !

P.S: What do you mean, neither of the two HCl recipes takes prodmods, at least not in pY 1 ?
Yeah, cages out of nowhere are annoying, still, it seems to have been designed like this on purpose (see also : limestone produced out of nowhere in the acetylene loop), unlike for efficiency modules in bioreserve collectors ?
(IMHO these limestone and cage loops should at least be designed so with maximum possible productivity you still don't get any extra material - after all the productivity modules are supposed to represent more efficient processes resulting in less ingredients wasted in botched recipes !)

[BlueTemplar]

Wow, looks like a temperature sensor does exist now ?!

[...]

Using this : https://mods.factorio.com/mod/FactorIO !
There is a sensor for fluid temperature.
[...]

Holy $#!+, is this actually possible ?!
Why did it take until 2018 for someone to make a mod like this ?!?