Thermoelectric Exchange CBM

It turns out this is a lot simpler than I thought, most of the relevant warmth/wet/wind values this bio needs seem to be consolidated in player.cpp, I was just looking in the wrong place this whole time.

Edited title to match the updated description thanks to darktoes.
“A biomimetic layer of thermoelectric material has been grafted into your skin, exploiting the difference in ambient and body temperature to produce power.”

I’ve been trying to replace the Internal Furnace CBM with Thermoelectric Exchange CBM in my build since the current benefit is … too quick. ie: “500+ PU per Log” ?

Its essentially a passive power source with the contact surface covering large parts of the body.
I was reusing parts of the internal climate control code in .cpp to do this until i realized doing it that way wouldn’t be an accurate description of what the bionic is supposed to do.

Different body parts experience different ambient temperatures depending on the clothing worn so a ‘general’ temperature just won’t be precise enough to account for exposed arms in the rain or wind passing over thinly covered legs, and I’m not familiar with body_part code.

Basically the bionic generates more power the further away ambient temperature is from the temperature of each body part, with Minus points from Insulation and Humidity followed by Plus points from Wind and Wet.
ie: Torso_Heat_Flow = (37c - Ambient) - (Insulation + Humidity) + (Wind + Wet).

This wont work well for warm/hot climates because the closer you get to core body temperature, the less difference there is to exploit, but its a different story for lower temperatures when you’re the only heat source around.

And any further decrease in ambient temperature would be counterbalanced by the risk of getting frostbite or dying.

What do you guys think? Is the bionic too weak? is replacing internal furnace too much?

Normally I keep any code changes i make to myself but i figure some of you guys might have the same … OCD about instant power-up CBM’s like the Internal Furnace.

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Seems strange, and awfully exploitable to just run an internal climate control cbm off of and stand in an ice lab.

One would assume that internal climate control would cancel out any benefit from thermal exchange if that were the case.

Besides I find it hard to imagine that any internal heating system would be more power efficient than drawing from the body’s waste heat.

It’s like putting an infrared solar panel below a light bulb to harvest the waste heat and expecting it to power a second light bulb.

Yes, that’s what I’m saying. it needs to be balanced around that.

So less than 1 PU/4 turns that’s already what i had in mind.

I was thinking of Thermo generating lower amounts than Joint Torsion which generates 1 PU/2 metres moved, since this is a passive bionic.

That’d actually be quite good for long reading sessions, sleeping, driving, etc. It might also be worth having it increase/decrease the character’s temperature a bit, but that might be overpowered.

You mean walk outside? sure you could do that if you wanted a better heat sink to increase power flow for the time being, but I get the feeling that’s not the objective most players have in mind when they step out of their shelters.

Sure its like having a 2nd Torsion Ratchet in terms of power gain but isn’t that the point of self improvement?

Bear in mind I’m also trying to replace the equally-if-not more overpowered Internal Furnace cbm, where i could spend a few minutes chopping down a tree to instantly restore thousands of PU from logs alone.

I like that image of a bionic smoke break though, it sounds pretty cool.

I meant have the bionic increase or decrease your own temperature while on, so you had to wear more/less clothes with it on.

Personally I think the internal furnace is a bit of a stretch realism wise but it is pretty cool. Also, it does take a pretty long time to cut down a tree and they aren’t renewable under normal circumstances.

Naw then it just becomes a 2nd internal climate control mod, and takes away from its original purpose.

Well having items burn slower like a charcoal kiln would see the furnace make more sense but at the moment its not where it should be, stretching the limits of belief like that.

I’m not even sure if its possible though since I haven’t seen any indication of mutation/bionics being able to save their own states. Maybe the capability is already written somewhere else in the code but I don’t know.


Maybe having a fake_item (Int_Furn) that acts exactly like a charcoal kiln with 0 weight would work.
As long as the burn timer is above 0, it produces power.
When it reaches 0, the fuel and fake_item disappear.

No? Just brainstorming here.

I meant more along the lines of it always raising your temperature. Make it uncomfortable to use indoors with normal clothing, to limit when it can be used.

Or make it lower your temperature, so you always have to wear extra clothing with it on.

Always raising your temperature? then the heat engine would stop working, there needs to be a flow of heat to generate any amount of power.

Always lowering your temperature implies that the bionic is actively refrigerating you, definitely not within the functions of a passive heat engine.

I doubt a skin graft of biomimetic materials would even provide that amount of insulation anyway.
As reducing the impedance of heat would likely be the first priority of any manufacturer looking to exploit thermal differences.

Perhaps the generation of energy stimulates the nerves in such a way that the body thinks it’s hotter/colder than it is? It forces the body to generate more heat for increased efficiency? I dunno, I was just trying to think of some balance techniques.

This is a ways outside my area of expertise, but if it’s generating power from your body heat it seems like it should absorb some of it and cool you.

Maybe more like warm you. I think it would absorb some of it and provide at least 1+ point of warmth.

As efficient as they are even heat engines generate their own waste heat.
It might be negligible on such small scales but covering large surfaces of the body might net you 1 point of warmth or 2.

In which case having it toggled for players wishing to shave off that bit of warmth would be the prudent thing to do but the material would still there under the skin, unless you’re like taking a scalpel to it.

I think its a small detail that could be overlooked as something barely noticeable at best.


This bionic works best when you’re not insulated by the way, so its not like you can strap on a suit of armor and expect the same performance. Bite wounds and low armor are things one would have to take into consideration when deciding how much use they want out of it.

If it’s taking your body heat and producing energy by allowing you to radiate it, then how could it produce body heat?

I’m not sure how you intend for this to work, but I’m basically imagining a thermocouple. One side is hot, one side is cold, the cold side gets hotter (and vice versa) inducing a current. I don’t see a reason you couldn’t do that all over the body and it would mean it would actually cool your body.

It wouldn’t, the layer itself would insulate you slightly.

Its not like the engine itself is colder than you, only the other side of it is.
The heat would have left the body anyway by radiation or convection, keeping a fraction of that energy in the system in the form of useful work like electricity is what the bionic would do while the rest of it becomes secondary waste heat.

No engine is 100% efficient.

Thermocouples would probably be more efficient than your body’s natural radiation, assuming your skin could take the excess heat.

It can’t be warmer than your body or no heat would flow into the engine, otherwise it would require energy to draw the heat into the engine, in which case you’re taking energy rather than generating it.

In terms of a heat engine, the thermocouples aren’t the engine. Your body is the engine and the heat radiating off it naturally is the waste energy. Thermocouples under the skin would only improve the efficiency of your own body as a heat engine, since some of your waste heat would become energy.

In fact, adding this as a separate bionic at all is silly. We should just make the internal climate control CBM generate electricity instead of using it up when the ambient temperature is lower than your internal temperature (which would be most of the time).

EDIT: Turns out, seems the human body is around 20% efficient while most thermocouples are only 5-8%, or up to 15% for some new experimental ones. Not sure if it would insulate you heavily and cook you alive or just only produce a miniscule amount of energy…

Thermocouples, you mean temp sensors? I kinda had Stirling engines in mind.
Ye regardless of the engine type the rest of its energy would just be unused motion.

Making Internal CC produce power was my first thought before reusing its code, until I remembered it takes energy to keep something the same temperature regardless of what the environment is like.

Unless there is an ICC Upgrade with a super-efficient heat engine on top of it, providing energy to refrigerate/warm with extra power to spare.

But multi-function bionics like that are a weird design choice, and I don’t think I’ve seen an example of one in Cataclysm.

Thermocouples are used in RTGs a lot. They’re inefficient, but they’re as simple as it gets, and the only thing I could see you fitting inside someone’s skin. I don’t think you could fit a Stirling engine inside someone.

It shouldn’t take energy to cool something hot in a cold environment, you just need to let the energy flow where it wants to. Thermocouples would let you control how much energy flows, so you could use it to heat or cool the skin, depending on whether you take or give it energy. Only problem is unless science made a breakthrough ingame, it would be less efficient than your body itself, so you would either cook yourself or freeze to death, depending on external conditions.

There is the advanced reactor which technically includes the dosimeter and radiation scrubber, but that’s the exception rather than the rule, and not a particularly good one at that since those are needed to stop it from killing you.

Right, I see your point about thermocouples.

Well the super science elements of 2045 in Cata don’t seem to obey today’s realism when it comes to efficiency, its just assumed that whatever breakthroughs were made before the apocalypse were thanks in large part to the use of xeno materials.

Problem is, heat doesn’t much like being made into electricity, so doing just that is difficult.

Having said that, we already have a bionic that steals enemy body heat and converts it into energy, so we could safely have this and handwave the science.