Lessons Of The Tribe

[DuckBoy]

Life wasn't easy before electricity.  Save the tribe with tips and tricks!

Instead of slaughtering your muffalo this winter, why not surprise her with a room full of roses, grown indoors by campfire light.  Roses (and dayblooms) grow in 1.5 days in 30% light conditions and provide a delectable .05 nutrition.  Train your growers all year long, and your muffalo (and colonists!) will thank you.  (You can do dandelions in 2.5 days for .18 nutrition outside, but at that point, maybe just switch to haygrass)

Sick of the endless raiding by your mother in law?  We have the perfect surprise for her too!  Just mine 40 jade and place it in the center of your room full of roses.  Now, place a crafting station and convert that beautiful (+6!) jade into a club.  Don't worry, it takes literally 0 crafting skill, and every jade club is better than even a good steel longsword. 

So winter is coming quickly, and that last raider torched your food supply before his awful pistol burned through your heal root supply.  Have no fear, you can grow food, healroot, even devilstrand harshest of winters, all you need is a TON of space, a TON of wood, and (optionally) some geothermal geysers.  Remember that temperature in an indoor, but unroofed, space does not instantly equalize with the outdoor temperature.  You can unroof skylights within rooms in your base to grow plants, and use either geothermal geysers or campfires to keep the rooms warm all winter long. 

Example: In an 8x8 room with a double thick wooden wall (12x12 total space) around a geyser, you can unroof exactly 15 tiles, leaving a 7x7 space for whatever else you want to build.  Warning:  If you choose to use geysers, watch the temperature inside closely over the non winter months, you may need to unroof, double wall, or even add campfires during a cold snap.  You can also use multiple campfires for truly intense cold. 

[Shurp]

Farming indoors with open skylights... that's genius!  But I imagine you need a boreal forest's worth of wood to keep it going!

(I dare someone to try to farm devilstrand this way)

Added bonus: safe from solar flares!

[Canute]

But you are doomed when you are run out of wood/trees.

Winter at temperated biome's are harmless, try out a biome with perma,. winter. :-)

[Shurp]

But would you run out of wood?

Think boreal forest, huge map, campfires last a day or two, right?  How much would could you grow... oh, wait, if it's cold you're not growing much wood.  So eventually the map runs out and you're done.  Hope you have solar power by then

OK, there's another angle on it -- which consumes less power, a sunlamp, or several heaters keeping partially unroofed 'greenhouses' warm?

[DuckBoy]

As far as I can tell, you can get up to 24.99999% of a room unroofed before temperature pops instantly to outside temps.  So expect an 8x8 room to support 4x4-1, a 16x16 room to support 8x8-1, and thus an nxn room to support (n/2 x n/2) - 1, at least for even n. 

A sunlamp can grow what... 11x11?  13x13?  Not even a full square.  The question then becomes, how many heaters does it take to heat a room of size 22x22 or 26x26.  Based on the wiki, a heater and a campfire supply exactly the same temperature.  Now this does depend on a lot of details in the temperature simulation that I don't know very well, but based on my campfire testing in the frozen tundra, I'd bet it's less than 8 with a standalone double walled room. 

I'm going to try adding another surrounding hallway for additional insulation which might be able to get the wood usage down even further, depending on where the temperature is leaking out. 

Do note that this does have limits:
There is a max room size before the room is considered outdoors.  --EDIT: This is false.  You can wall the entire map into a 60000 cell room if you like.  Outdoors is just a word for having lots of unroofed area.--
Crops harvested and left in this room get hurt by sunlight. 
Power/wood outages wreck your crops almost as fast as growing hydroponics. 

Finally, as a question for future research:  I believe you can heat a massive room for free with a single skill-less pawn throwing molotov cocktails in the corner.  I don't think you can beat the efficiency of the skylight plan in that case. 

[DuckBoy]

Sustained 34 degree temperature differential from 6 campfires in a 16x16 room:

[Shurp]

So you have 66 squares vs the 100 of a sunlamp.  A heater runs at 175 * 6 * (100/66) = 1500 W vs. 2900 W for a sunlamp.  But the sunlamp is on for only a portion of the day; I think 1800 is the net power per day.  Meaning the open roof is slightly better, but then you have to take into account how much light you actually get up north and such.

So the campfire method is definitely workable.  The heater method is probably more trouble than it's worth.  (Especially when you consider the component cost of all those heaters)

Oh, that's neat, I just noticed you're making good use of all that extra space for your workshop and barracks.  That's a great tribal base design!

[DuckBoy]

A great many tribals died performing science today.  They also called upon the wisdom of the ancients (https://www.reddit.com/r/RimWorld/comments/52980c/the_thermodynamics_of_rimworld/), the modders, some xml, and debug mode. 


First, let's talk about heat loss.  I'm going to simplify and ONLY use double walls.

As visible in debug mode (through options, debug mode)
A room computes how much heat is transferred (lost, gained) as a function of
W = Double Walls along the perimeter
R = Thin Roofed Tiles
U = Unroofed Tiles
C = Overhead Mountain Tiles
T = Temperature Differential With Outside Temp

For an NxN interior with a thin roof, this function is approximately:
HeatTransfer = 4 * N * W * T + N * N * R * T

For an NxN interior with 25% unroofed, this function is approximately
HeatTransfer = 4 * N * W * T + N * N * .75 * R * T + N * N * .25 * U * T

Based on my testing and research
W = 0.0001
R = 0.00006
U = 0.0008
C = 0 (For Indoor Temperature < 15)

This is to say, Walls leak 5/3 faster than thin roof tiles, and unroofed tiles leak 8 times faster than walls (~13.3 * thin roof).  Further, overhead mountain roofs do not leak -AT ALL- (for temperature < 15). 

In practice, this means for a 10x10 room 40% of the heat leaks out through walls, and 60% leaks out through roof tiles.  For a 30x30 room, only 18% of the heat leaks out through walls, the other 82% of the heat leaks out through roof tiles.  Due to the n^2 term, the thin roof dominates heat loss as the size of the room increases. 


Now, let's talk about creating heat.  Rimworld uses a system called energy per second (eps).  I believe I have identified all sources of eps:

Electric Smelter 12 eps
Electric Crematorium 15 eps
Wood Fired Generator 4 eps
Chem Fuel Generator 3 eps
Camp Fire 21 eps
Heater 21 eps
Passive Cooler -11 eps
Air Conditioner -21 eps
Insect Hive 7eps (Yes, really.  Counter challenge you to grow devilstrand in a tundra with this as your only heat source!)
Torch Lamp 3.5 eps

There are also a number of other less regular sources that I will list without units, as I have not perfectly tracked down when they apply heat.  Take these with a grain of salt. 

Frag grenades/Explosions: 5
Fire: 160 (Not as big as you think, it is applied once for every 7.5x campfire heat generation intervals.  Tier of fire may multiply heat generation.)
Steam Geyser IntermittentSteamSprayer: 40 (while active, active period is random, anywhere from 10% to 50% of the time)


Finally, let's put it all together. 

As shown by the eps counts, campfires and heaters are indeed interchangeable.  Torch lamps are less wood efficient than campfires.  Wood fired generators and chem fuel generators are interesting, but out of scope.  Same for fire.  Geysers can be treated as a less reliable campfire, I suspect that on average, they are slightly weaker than a campfire overall.  Campfires and heaters are therefore your most efficient non-exotic heat sources. 

Let's return to the heat loss equation. 
ThinRoofedHeatTransfer = 4 * N * W * T + N * N * R * T
UnroofedHeatTransfer = 4 * N * W * T + .75 * N * N * R * T + .25 * N * N * U * T
UnroofedHeatTransfer = ThinRoofedHeatTransfer - .25 * N * N * R * T + .25 * N * N * U * T

As shown by heat loss calculations, every unroofed tile is approximately 13 thin roof tiles. 
UnroofedHeatTransfer = ThinRoofedHeatTransfer + .25 * N * N * 12 R * T
UnroofedHeatTransfer = ThinRoofedHeatTransfer + 3 * N * N * R * T

That is, unroofing 25% is equivalent to quadrupling the internal space as far as heat loss is concerned.

As such, for any room that you can sustainably heat above 10 degrees C with X campfires with a thin roof in your chosen biome, you can remove 25% - 1 of its roof tiles for indoor growing with less than or equal to 4X campfires. 



And finally, back to the real topic of this thread.  Hey tribals in tundras and boreal forests, you can heat HUGE overhead mountain areas with a single campfire in absurdly cold conditions!

[Shurp]

And finally, back to the real topic of this thread.  Hey tribals in tundras and boreal forests, you can heat HUGE overhead mountain areas with a single campfire in absurdly cold conditions!

And then die horribly when insects spawn and eat your tribe

[TheMeInTeam]

Farming indoors with open skylights... that's genius!  But I imagine you need a boreal forest's worth of wood to keep it going!

(I dare someone to try to farm devilstrand this way)

Added bonus: safe from solar flares!

The bigger issue is doing it when far north or south; external light is actually realistically terrible for much of the year in these biomes, making food yield on a small number of ground tiles pretty awful per time.

When closer to the equator this isn't true, but those usually have growing seasons.  This tip is actually best on those worlds rigged to be cold, where you can have permawinter at the equator, use this trick, and grow at regular light values.

Also normal indoor growing will not die to solar flares, just hydroponics.  Hydroponics are really an ice sheet/sea ice only thing though; usually just making an extra sunlamp on regular soil is better than throwing all those extra components/steel around (way more to spam basins than power another sunlamp, and more maintenance replacing breakdowns).  On extreme deserts you can just plant in gravel, they usually have growing seasons.

Finally, as a question for future research:  I believe you can heat a massive room for free with a single skill-less pawn throwing molotov cocktails in the corner.  I don't think you can beat the efficiency of the skylight plan in that case. 

Hahahahahaha!  This is something I had not considered, that's pretty awesome.  Usually takes a bit for tribesmen to get one.  Kind of dangerous to try to perma-sustain that, would need day/night shifts with a ton of micro.
[/quote]

And finally, back to the real topic of this thread.  Hey tribals in tundras and boreal forests, you can heat HUGE overhead mountain areas with a single campfire in absurdly cold conditions!

Their problem is more so growing/hunting food .  On biomes tundra or easier you get enough game to hunt to keep a small colony going, and are typically able to loot warm enough clothing such that only bedrooms need to be heated.  These can be in overhead mountain as you say to save wood, but infestation chance there isn't pleasant and even in tundra you usually have > 1000 wood to work with, plenty of time to research before running out of that.

It's tribal ice sheet where it starts getting hard, and tribal sea ice where it gets super RNG.

[Snafu_RW]

A great many tribals died performing science today.  They also called upon the wisdom of the ancients (https://www.reddit.com/r/RimWorld/comments/52980c/the_thermodynamics_of_rimworld/), the modders, some xml, and debug mode. 
[... etc]

V. interesting. So (fuelled/electric) cook stoves don't generate heat? That's.. unusual

[DuckBoy]

If they do, they don't use the constant push per time interval of the other buildings, nor the GenTemperature.pushHeat call of Fire and SteamGeyserSpray one shot events.  Doesn't mean it isn't elsewhere in the code though. 

The ancient wisdom specifies an exploit that produces a perfect seal in a room under a mountain below 15 degrees C, if that still works, you may be able to test it by dropping a pawn in and making a few hundred meals to raise the temperature up to 15.