Heat Pipe Math for Aquilo

[jimbroof]

Hi everyone,

I recently landed on Aquilo for the first time and I'm finding that it would be nice to fully understand the math behind heat transfer through heat pipes. The wiki page has this to say about the topic:

> with P being the power going through this entity expressed in MW ... we can thus express the maximum length of a straight line of heat pipe as 500 / (1 + P/15)

The "500" in the numerator comes from the scenario where a nuclear reactor is running at 1000 C and connected to a heat exchanger which requires a 500 C connection; in other words, the numerator in this formula is the maximum allowed temperature difference between the source and the destination.

On Aquilo an entity will freeze if its temperature is below 30 C. I can assume that my reactor setup will generate around 1GW of power, so I plug these numbers into the formula: Maximum heat pipe distance = (1000 - 30) / (1 + 1000/15). This gives me a distance estimate of about 14 tiles. Which is obviously wrong.

Looking more closely at the formula I'm noticing that as power increases the expected distance decreases, which makes no sense to me. Am I misinterpreting something here, or is the wiki just completely wrong on this one? If the latter, has anyone come across an accurate formula?

Edit: I was assuming that P is just the power input. It appears that P is determined as min(max source power, destination power draw). So if a reactor is producing 40mw but your heat exchangers or freezable entities are only using 10mw, then P = 30. Leaving this up for now in case it helps someone else

[computeraddict]

What's unobvious about the Aquilo heat piping is how much each entity draws to keep warm

[jdrexler75]

Yeah, distance is not relevant, it's limited to 969 tiles away from the source due to the minimum 1 K difference between adjacent heat pipes. What matters is how many entities you can keep warm. I don't have hard math to back this up, but each entity that's connected to your heat pipes seems to draw heating power equal to the number of titles it occupies. Heat pipes on their own lose no heat to the ground however.

One 40 MW heating tower can support about 1000 tiles, so probably each tile draws around 40 kW.

[Mr Wednesday]

The power draw to keep different things warm is at least documented in the wiki. It's not as simple as the number of tiles occupied.

When I was planning out my Aquilo base, I set up a spreadsheet with estimated numbers of different things and the heat loss for each of them so I could figure out the thermal power demand (and make sure I could satisfy it).

[jdrexler75]

The power draw to keep different things warm is at least documented in the wiki. It's not as simple as the number of tiles occupied.

Huh, I should've checked back more often. On average 40 kW per tile seems to be a decent rule of thumb, guess I got lucky.

[Tertius]

I did a rough calculation of item heating power consumption according to the wiki Aquilo page and built one heating tower per approx. 30 MW heating requirement to be on the safe side. I completely ignored distance calculations.
My rule of thumb: for one heating tower providing heat, I can build approx. 200 blue underground belts or undergrund pipes. Everything else doesn't matter that much, 1 underground piece counts as much as a hand full of other items except the assembling machine variants, who need almost as much as one underground piece. In the end, I built perhaps double the heating towers than required, but who cares? It's so cheap, and rocket fuel is free on Aquilo.

For energy production I added dedicated heating towers, according to the desired energy power production (40 MW per tower), just as you would calculate for nuclear power.