Thermodynamics 101

[carewolf]

I wouldn't use the 175 watt heaters as a "reasonable example" of anything, though.  Multiply the wattage by 10 and now you're in the range of "Portable Space Heaters".

Yes and i forgot about those. Such heater should have at least 2kW to heat up a small room. If i remember correctly, we need around 100W to heat up a 1m2 in winter, with good thermal isolation etc. Without isolation (steel or stone walls) it should be 200W or more. So for small rimworld bedroom 4x4 with very poor isolation and a thin steel tile roof, we need at least 3kW to keep it warm.

I grew up in a house with electric heating and cold winters. We had 1000-2000W heaters in each room depending on size. But the didn't actually use anywhere near their maximum capacity most of the time. On average a 20m² room would use 100-200W of heating. The full power is only needed to warm a cold room in a reasonable time after airing out (which also meant you couldn't reheat all rooms at the same time as that would blow the fuses to the entire house).

[Perq]

I wouldn't use the 175 watt heaters as a "reasonable example" of anything, though.  Multiply the wattage by 10 and now you're in the range of "Portable Space Heaters".

Yes and i forgot about those. Such heater should have at least 2kW to heat up a small room. If i remember correctly, we need around 100W to heat up a 1m2 in winter, with good thermal isolation etc. Without isolation (steel or stone walls) it should be 200W or more. So for small rimworld bedroom 4x4 with very poor isolation and a thin steel tile roof, we need at least 3kW to keep it warm.

I grew up in a house with electric heating and cold winters. We had 1000-2000W heaters in each room depending on size. But the didn't actually use anywhere near their maximum capacity most of the time. On average a 20m² room would use 100-200W of heating. The full power is only needed to warm a cold room in a reasonable time after airing out (which also meant you couldn't reheat all rooms at the same time as that would blow the fuses to the entire house).

Absolutely not. You either had super-efficient insulation (like spaceship level efficient), or it was like 10oC outside. :V I actually have masters in power engineering (if something like that exists in the west - it sure does here, in Poland ), and I can guarantee you that 200W is nowhere near enough for a free-standing house to be heated during cold winter. Again, a human is considered to be a source of 100W of heat. This would mean such room could be heated by simply adding 2 people to it, which is obviously bollocks. :V

Also, if you had electric heating in your house (and only that) fuses were also designed to be able to operate in such conditions. If I were to guess, I'd go with three-phase on that, but nothing guaranteed. :2

If you really want me to, I can make you some calculations for the designed heating power (or whatever it is called) - the way you determine how much heating capacity you want to have in your house.

[b0rsuk]

If carewolf lives in some northern country like Finland, Sweden or Denmark I wouldn't be surprised if he did have a super efficiently isolated house. Poland is known for cheap, shoddy craftsmanship, short-term thinking and saving pennies on material quality. Low prices are most common thing advertised on billboards. I know - I live here. By the way, Poland's best university is barely in the top 300 universities of the world, and it's getting money cut because of political reasons. So unless you made your degree somewhere abroad... yeah. Nordic and Scandinavian countries have people who value quality, good design and wisdom.

[Catastrophy]

It's a simplified model for gameplay reasons. A useful heater should probably be a magnitude up in power, but whatever.
I find this "a human is a 100W heater" kinda funny. Isn't the purpose to keep the warm inside the body? Not exactly good radiators.

[Perq]

If carewolf lives in some northern country like Finland, Sweden or Denmark I wouldn't be surprised if he did have a super efficiently isolated house. Poland is known for cheap, shoddy craftsmanship, short-term thinking and saving pennies on material quality. Low prices are most common thing advertised on billboards. I know - I live here. By the way, Poland's best university is barely in the top 300 universities of the world, and it's getting money cut because of political reasons. So unless you made your degree somewhere abroad... yeah. Nordic and Scandinavian countries have people who value quality, good design and wisdom.

Lol, are you undermining what I said because I'm from Poland? D:
Also, you want to check those lists of top universities, namely those in US, who are promoting absurd Kickstarter projects and BLM and what not. Don't want to undermine their credibility (nor to open can of worms about them), but suggesting I can't be right because Polish Universities are so top 300 is pretty silly. :2 Look up the facts for yourself instead of guessing.

By the way, good insulation (the good quality North you are suggesting) does not mean it is any different from what we are using in Poland.
Execution, yes. Materials - no. The poor, cheap houses you are talking about are usually 40+ years old.

But, well, you REALLY want me to bring you these calculations, don't you?

[Hans Lemurson]

...
But, well, you REALLY want me to bring you these calculations, don't you?

NUMBERS FIIIIIIGHT!!!!! 

On a different subject though, I have found that Heat seems to only be conducted in straight lines.  A room that touches another room corner-to-corner will receive no heat from it.

[Bozobub]

This is possibly the best place to remember "It's a GAME, silly!"

No, not all light from any fixture (greenhouse lamp or not) is converted back to heat.  Yes, the plants absorb a good bit, and so does literally every other surface.  A large part of that will be re-radiated back inside as heat but some will be radiated out of the structure by traveling through the walls — no matter how good your insulation is — some will be consumed by various microflora/fauna present on every surface, and some will drive miscellaneous photochemical reactions that "lock up" energy.

As for whether or not 175 watts can be enough heat to warm a room, damn straight it can, at least for a small room!  If the room has enough insulation/surrounding thermal mass, this is nowhere near as difficult as you might think.  You'd definitely, however, have issues with fresh air circulation; this would kill most kinds of plants pretty fast, much less humans .  So, impossible?  Nah.  Likely to be used as a regular heating source?  Nah x2 - lol.  Suffocation isn't much fun.

Off the cuff, I'd estimate about 1000 watts of heat for a reasonably well-insulated 10x10x10 cubical room/building in very cold (freezing or below) weather, although that's probably lowballing it a bit.  Using that rough estimate, I'd guess 1200w or so of lighting would be enough for this purpose, if relying exclusively on lighting for both heat and illumination.

This actually meshes pretty well with my experience with growing weed, by the by, although it's a good bit more efficient than our current tech.  You can also increase the effect of limited light by keeping the source very close to the plant, thus increasing light flux on the plant's surface via the "inverse-square" law.  I used this to greatly increase the effectiveness of fluorescent fixtures, while using far less power than sodium-halide or standard halogen lamps.  Similarly, a lot of growers are starting to use multi-spectrum LEDs exactly this way; less heat, far more efficiency, and much more reliability.

It actually takes startlingly small wattage to power lights meant just for growing, as long as the spectrum involved is suitable.  Remember, current LED lamps meant for illumination commonly run 9-12 watts and ones meant for growing often run 10-50 watts (50 watts is a GIGANTIC LED lamp o.O').

Tl;dr?  I don't blame you .  The short of it is, while the space heaters in Rimworld aren't even remotely realistic, the sunlamps are at least plausible.

[Hans Lemurson]

Tl;dr?  I don't blame you .  The short of it is, while the space heaters in Rimworld aren't even remotely realistic, the sunlamps are at least plausible.

Plausible for 20 tiles, maybe, but not 100.

[Bozobub]

At the wattage given — 1600w— sorry, I can't agree.  You could place 32 50-watt LED fixtures in that space, and yes, it would work just fine.  And that's with TODAY'S tech.  I don't think you have any real comprehension of how ridiculously bright a 50w LED fixture is; a 50w LED gives off about as much light as a 250w halogen fixture! (example)

The only real caveat is that you need the proper "color" LEDs — by default, they're very, very "blue" to give the illusion of white light*, since they are actually monochromatic, similar to a laser — or you won't get optimal results. (although it will still WORK).  So your grow room would likely have either a markedly reddish tint to the lighting, or multi-LED fixtures would be used for a "full spectrum".  Fluorescents usually are rather blue as well but can be coated internally to give off a more useful (and wider, if desired) spectrum.
________
*This is implicated, btw, in a significant number of health problems in humans , including retina damage and sleep issues.

[TheMeInTeam]

Absolutely not. You either had super-efficient insulation (like spaceship level efficient), or it was like 10oC outside. :V I actually have masters in power engineering (if something like that exists in the west - it sure does here, in Poland )

The US equivalent is called electrical engineering, if it's the program I'm picturing.  Engineering is not easy stuff so don't forget you're a few inferential distance iterations in front of a lay person in understanding.

Regardless, it's pretty obvious the game intentionally doesn't care about the realism of absolute scale...or about energy in general overmuch. 

As we have discovered in another thread, it is possible to burn trees to heat/light further tree growing and come out slightly ahead in energy in this game, so I wouldn't worry overmuch about accurate wattage or scaling of energy usage of devices to real-world equivalents.  When you're modeling a system where even the trees disobey thermodynamics I don't think our physics apply in general .

[Bozobub]

{snip}

Exactly.

[Jovus]

When you're modeling a system where even the trees disobey thermodynamics I don't think our physics apply in general .

And this isn't bad. In fact, it's good, because what I want is a game that will run on my box, not a detailed statistical mechanics simulation that won't.

(Detailed statistical mechanics simulations are resource-intensive. I should know; I make them.)

Which isn't to say that people should stop posting in this thread or anything. Making fun of something we all enjoy because of its 'flaws' is part of the fun.

[Hans Lemurson]

I made a test world to try out a bunch of different configurations for rooms and walls to see how insulation works.  Heat Conduction occurs only in straight lines.  It will not move diagonally, and it will not turn corners.


The right-hand building provides the best example of this.  The two heaters were able to thaw the snow in their rooms (95c) and the rooms adjacent to them (20c), but the central one-tile room remains frozen, equilibrated with the outside temperature of -7 degrees.

Other observations:

• The corners of walls can be left entirely empty with no effect on the internal room temperature.
• Double-walls have roughly twice the insulation as single-walls. (Can achieve the same temperature difference with half the heat)
• Insulation maxes out at wall-thickness of 2.  Anything beyond that has no detectable effect.
• A room with double-walls will lose heat to the environment, but seems to provide no detectable heat to neighboring rooms.  Surround a double-thick room with an outer wall (roofed over, of course), and the space between them will be scarcely different than the outside temperature.

[Perq]

Absolutely not. You either had super-efficient insulation (like spaceship level efficient), or it was like 10oC outside. :V I actually have masters in power engineering (if something like that exists in the west - it sure does here, in Poland )

The US equivalent is called electrical engineering, if it's the program I'm picturing.  Engineering is not easy stuff so don't forget you're a few inferential distance iterations in front of a lay person in understanding.

Regardless, it's pretty obvious the game intentionally doesn't care about the realism of absolute scale...or about energy in general overmuch. 

As we have discovered in another thread, it is possible to burn trees to heat/light further tree growing and come out slightly ahead in energy in this game, so I wouldn't worry overmuch about accurate wattage or scaling of energy usage of devices to real-world equivalents.  When you're modeling a system where even the trees disobey thermodynamics I don't think our physics apply in general .

Well, yeah, that is the point of this thread, I guess? We're still in Alpha, stuff will be changed, and if we provide enough accurate (so no I think it works that way or My friend of friend told me that...) information/feedback, it is only for the better, amarite?

Nobody is calling to make it mesh-calculations - by simply adjusting the numbers, so that they make sense both gameplay wise and are somewhat realistic, it is enough. Having a 175W heater doesn't feel right.

I actually have masters in power engineering (if something like that exists in the west - it sure does here, in Poland )

The US equivalent is called electrical engineering, if it's the program I'm picturing.  Engineering is not easy stuff so don't forget you're a few inferential distance iterations in front of a lay person in understanding.

Hmmm, my degree actually deals more with energy than electricity (but does not exclude electricity, naturally). It includes powerhouse level turbines, engines, heat exchangers, pumps (from mechanical and hydromechanical standpoint) but also transformers, electrical engines, power lines and so on. 

[Bozobub]

Frankly, I can't be bothered to care overmuch, even though it's fun to speculate on the "why" and "how" of the mechanics.  Remember, the essential point of the current values given is to effect a specific balance of resources (man-hours, materials, power) in the game, not pretend to be a fine-grained reality sim .