>>4283 >I was thinking that the internal air and coolant tube in the left lung of the diagram could be kept completely closed in order to limit the need for a filter I see, ofc that's a good idea. I forgot about that constraint. >while the right lung would just expand and contract in order to circulate out the hot air as it is dispersed by a heat sink. The more I think about this, the more I like the idea of devising a bellows arrangement. Not only can it be quite efficient mechanical-energy-wise, but it also will nicely mimic human breathing patterns. And that can only be a plus on cold, snuggly nights together with robowaifu. :^) >The left lung would probably need a fan to keep air flowing and a pump to keep the liquid flowing, Yes, unless we can take advantage of the bellows mechanism for the airflow on that side as well. And the liquid might be able to gain by some sort of bladders around the robowaifu (that could ostensibly be used for padding, shape & form, etc) that could be passive pumping action by her day-to-day movements, etc. Probably would only serve as a small ancillary boost to the fluid pump's basic work, but every little helps. It will all need to be analyzed in the end for cost/benefit against the energy budget. But things like temporarily storing momentum inside rotating flywheels is well understood now, so we might find little bonus energy savings like that with a little clever exploration. >but my concern is that one or even a few coolers may not be enough. Probably not, unless it was a big honking one. Any information on the available plate sizes on these things Anon? >From what I can find, silicone is just a generally insulating material. Yeah, makes sense ofc. >There seem to be a few examples of heat spreading, which is very good, but none of them are elastic enough to be used as a skin Hmm, that's interesting. Since from a systems engineering perspective, we already need to solve differing surface materials with differing softness/resiliency then we might just be able to capitalize on that fact by judicious use of these materials. Can you provide more information on your findings here? >I don't see a better alternative to a silicone elastomer as skin, but given the low conductivity it could prove challenging Agreed. Good post Anon.

>>4303 >bellows arrangement The artificial lung system could probably be supported by a diaphragm type muscle that separates it from what would be the liver, stomach, and intestinal tract in a human. Considering the limited space for computation and other potential features, it might not be space efficient enough, but it is definitely an interesting idea. If the closed loop lung is hooked up with a couple valves it could possibly be used to naturally pump air through the air veins in the same way the heart pumps blood, but it probably isn't the most efficient system. Technically, it may be possible to pump coolant in the same way we pump blood as well, but with a centrally located dedicated artificial heart. >Any information on the available plate sizes on these things Anon? The small ones are only about $3 each, but plate size doesn't seem to be as important as having a good heat sink. Without any sort of fan the things will overheat, so what seems to matter is more the transference of the heat. I gather that depending on the voltage applied, each side will have a difference of about 30 C. This does mean that if the device itself heats up too much the cold side will heat up along with the warm side, so venting that heat is a must. Unfortunately, even with a heat sink and a diaphragm it may not be enough to disperse the heat quickly enough, even for a single very small plate.

>>4334 >Considering the limited space for computation and other potential features The general consensus (I think) is to house all the SBCs and other sensitive electronics in a 'breadbox' that would both serve as a cushioned hardshell for physical protection, and a Faraday-cage for RF protection. It also simplifies the cooling need for the computers as well. So, I think some sort of central lever arm back near the spine, that spans the chest transversely, that slowly pumps two cylinders situated on either side of the central breadbox might be a feasible approach to have this bellows solution and still share the space with other components. Think sort of where our lungs are, but half the size and situated just inside our ribcage on the far right and far left of her chest. >Technically, it may be possible to pump coolant in the same way we pump blood as well, but with a centrally located dedicated artificial heart. Yeah, that's perfect. We need some sort of centralized thermal management core, probably just above the breadbox. That way the exchange of heat can be simplified by being near the 'lungs' and also directly adjacent to the breadbox (which will be a significant heat source). >but plate size doesn't seem to be as important as having a good heat sink That seems to suggest we have some honking big spun-aluminum fins situated on both the hot and the cold sides inside the central thermal mgmt core. >Unfortunately, even with a heat sink and a diaphragm it may not be enough to disperse the heat quickly enough, even for a single very small plate We can add a forced-air fan and vent heat directly out her upper back near the neck, as it will literally be 1 inch away from the core. Care to off critiques of my suggestions here Anon?

>>4348 >Care to offer* >"Your post looks like spam. Please adjust it."

>>4348 Hard to visualize without a diagram, but I think I get the picture. It could work, but without knowing how much heat will be produced from the various motors and electronics as well as how much heat can be dispersed with this method, I think it may be impossible to tell until a general model is made and tests are run. Really, as long as we can get a decent body made we can probably adjust the temperature needs once we have the limbs, muscles, and general torso blocked out.

>>4359 >I think it may be impossible to tell until a general model is made and tests are run Agreed. I'll break out the old mouse and try to knock together 9'001 hours in MS Paint for you here.

> RF protection I had the same idea. However, premium models will need to use a lot of conductive material for sensors in the skin anyways, which might also help with heat dissipation. So it has a triple use, but will be expensive. > Breadbox I'm thinking of using air tanks in the head and/or upper chest. Computers would be inside or outside of these. Either way, using the heat to increase the pressure. Additional cooling should kick in if necessary. Tanks on the other side could use hot water from other areas to heat themselves up. > 4283 What do you think about only having a thin skin of silicone/spandex on top, underneath conductive material like textiles with silver and underneath that, tubes with the hot water, maybe with some conductive connections to a higher layer. How could we test stuff like that? Hot-water bottles are made out of silicone, I think. If we test how much time it takes to cool a bit down, and compare it to a scenario in which there are other layers on top and heat can't go away to the side bc styrofoam? Then we would know a bit more.

>>4371 >How could we test stuff like that? I guess buy a couple of water bottles, a heater, a thermometer, a stopwatch, and some styrofoam? No time like the present to run your own scientific experiments right?

>>4377 I thought about it a bit more, I might first need a thermometer with a water probe. Then, using only two flexible tubes glued side by side with a little distance between them. One side with four layers of thin textiles with a thin layer of silicone on top. The other sides need to be isolated much more. Of course, this doesn't account for new heat coming in. It will just show if the water cools down in a certain amount of time. I'll try that in some time, don't know when, but it's on my mind.

>>4424 Aquarium supply stores can provide both water-immersible heaters and thermometers Anon. Buy a cheap strofoam cooler as your basic containment vessel and you can get a 2-pack of gatorade and chug them to get your bottles. Sound good?

>>4433 I don't need bottles, since I already have the tubes. With hot-water bottle I meant one out of silicone to put on a belly. But, yeah I might have a pet shop here, I planned to go with AliExpress bc prices and it isn't urgent. We'll see.

Did anyone consider heatpipes? The fastest heat conductor? https://youtu.be/OR8u__Hcb3k https://youtu.be/BCQKwMSgmRI https://youtu.be/ezb3qRq3ACc Maybe useful for some areas which aren't bending.

>>4443 Definitely. Heat pipes are extremely effective at bringing heat from one place to another. I don't think the robot could likely function without them. I guess the question is where they could be used most effectively. Around the computation would be the most obvious of course, but there is the potential for their use generally in the torso. Shame there aren't any small flexible heat pipes, but is makes sense given the design.

>>4446 They might help here and there with getting heat away from motors and batteries, not only computers. In the bigger ones heat cold be distributed over longer distances if we make the pipes part of some bones, which would also make them sturdier.

>>4446 >Shame there aren't any small flexible heat pipes, but is makes sense given the design. This may not be flexible Anon, but it looks pretty small (in diameter) to me. > (1) >sauce: https://en.wikipedia.org/wiki/Heat_pipe / other commercial info https://www.heatpipe.com/what-are-heat-pipes/ https://www.1-act.com/innovations/heat-pipes/ Also, there are flat heat-sink versions that perform a similar function, if not as efficiently. > (3) https://en.wikipedia.org/wiki/Heat_spreader

>>4469 >related >Your post looks like spam, please adjust it.

An engineering specialty I find particularly interesting is a Spacecraft thermal control system (TCS). These systems have lots of budget, and the stakes are quite high (both for success and for failure). https://en.wikipedia.org/wiki/Spacecraft_thermal_control Surely this domain offers lots of informative lessons for /robowaifu/ to learn from? A wide array of agencies, institutions, and organizations have been doing this kind of thing for 60+ years now.

Thermal pads might be very usefull for areas where there's not much space. They could transport heat horizontal. They're are not so good for replacing thermal paste: https://youtu.be/ipFhGlt8Qkw I recalled that video and method when thinking about having some motors and solenoids side by side, we can't put a watercooler in between in every case (bc space) and air might also not be a option in every case.

>related xpost >>8986

What about Stirling Engines, /robowaifu/ ? Surely some areas of the breadbox and hip/shoulder actuators will get quite hot enough to run some type or other of one of these things? https://en.wikipedia.org/wiki/Stirling_engine

>>9572 >related

>>9572 I think to have any reasonable shot at success, the waste heat will need to be piped directly into a central heat consolidator, and a single Stirling engine located attached to it. This might be enough heat to gain enough effective work to make it worthwhile. Of course, all the cooling systems for the robowaifu would also need to route directly there as well, whether liquid or air based. These things must have both a hot and a cold side to work at all.

I don't consider that to be a good idea, however he is building one: https://youtu.be/eZUteOLEKz8 - I'd rather use something like that externally to harvest solar thermic energy to gain electricity, and then one use cases would be charging robowaifus. So it's more of a prepper thing, or pushing alternatives to carbon based energy, and maybe for hiding huge energy consumption from the officials.

Insects have it better on cooling. Using exhaust ports for pushing hot air out. So we can probably have a dual system for passive and acrive cooling. Just put vents mainly at the core and at the limbs so when she passive cools you can feel heat as well.

>>9587 Dependent on the kind of build, there's a big vent - the mouth. Let's just use this one, or not? Also heat is usefull to be spread out throughout the outer shell which might be some kind of skin. Then it will radiate out, no extra holes required.

>>9587 >>9594 Certainly, all three forms of heat transfer conduction, convection (forced or otherwise), and radiation will all play a role in keeping our robowaifus cooled off. But Anon is right >>9585 if for no other reason than the loud noise associated with the mechanisms of the engine. I withdraw the suggestion, as far as in internal device in our robowaifus. :^)

>>11080 Related. https://en.wikipedia.org/wiki/Thermoelectric_cooling While not as efficient as Carnot Cycle cooling, it's advantages of it's solid state nature (no moving parts, low maintenance, compact size, and orientation insensitivity) are highly-valuable characteristics for robowaifu designs.

In the event that cheap, high-temperature superconducting, supercomputing hardware becomes available for our robowaifus, we can even create our own liquid nitrogen directly from the air itself. There are small commercial systems already available for this: https://www.cryomech.com/liquid-nitrogen-plants/ Or, even homemade systems are possible! https://www.instructables.com/Homemade-liquid-nitrogen-generator/

>>11069 >>11086 In regards to the concept of Processors and Chips embedded 3d in a liquid or gel or resin substrate https://www.nature.com/articles/s41598-020-71745-w >Electrically insulating and thermally conductive polymer matrix composites are desirable for industry applications as they improve the reliability of high-performance electronic devices, particularly via heat dissipation in devices loaded with several electronic components. In this study, an aggregated β-Si3N4 filler with randomly oriented grains was produced via combustion synthesis to improve the thermal conductivity of epoxy composites. The thermal conductivities of the prepared composites were investigated as a function of the filler content, and the values were compared to those of composites loaded with commercial β-Si3N4 (non-aggregated). Negligible difference was observed in the thermal conductivities of both types of composites when the Si3N4 content was below 40 vol%; however, above 40 vol%, the aggregated β-Si3N4 filler-loaded composites showed higher thermal conductivities than the commercial β-Si3N4-loaded composites. The aggregated β-Si3N4 filler-loaded composites exhibited isotropic thermal conductivities with a maximum value of 4.7 W m−1 K−1 at 53 vol% filler content, which is approximately 2.4 times higher than that of the commercial β-Si3N4-loaded composites, thereby suggesting that the morphology of the aggregated filler would be more efficient than that of the commonly used non-aggregated filler in enhancing the thermal conductivity of a polymer matrix composite. >Improving the thermal conductivity of epoxy composites using a combustion-synthesized aggregated β-Si3N4 filler with randomly oriented grains https://iopscience.iop.org/article/10.1088/2053-1591/ab2215 >We report on the thermal and electrical properties of hybrid epoxy composites with graphene and boron nitride fillers. The thicknesses, lateral dimensions, and aspect ratios of each filler material were intentionally selected for geometric similarity to one another, in contrast to prior studies that utilized dissimilar filler geometries to achieve a 'synergistic' effect. We demonstrate that the electrically-conductive graphene and electrically-insulating boron nitride fillers allow one to effectively engineer the thermal and electrical conductivities of their resulting composites. By varying the constituent fraction of boron nitride to graphene in a composite with ~44% total filler loading, one can tune the thermal conductivity enhancement from a factor of ×15 to ×35 and increase the electrical conductivity by many orders of magnitude. The obtained results are important for the development of next-generation thermal interface materials with controllable electrical properties necessary for applications requiring either electrical grounding or insulation.

>>11106 It's really encouraging to see an explicit focus on this Anon, it sounds promising. Any change a materials-science/ME/physicist can give us all a tl;dr ? To wit; is it at all likely that we, as hobbyists, be able to use this in our robowaifus within say, 5 years?

>>11111 I mean we could literally use Silicone oil now as its available at any hardware store. Obtaining graphene is not unreasonable, I think there's even a process for making it at home (I'll let you google this since there are so many results), and epoxy is also readily available (new age types use it to make those "orgone generators") Now the tricky part, actually applying this. Personally I'd like to see a demonstration with a custom "flexible-pcb" bus linking a CPU to memory and ports (could be mini usb or usb C instead of standard), like an "uncrushable" raspberry Pi. Something that would flex if dropped rather than crack open. Then I would see how miniaturized we could get it, and surround it inside a mold with either the Silicone Oil inside of a bladder of sorts, or simply the epoxy with graphene and let it harden (with the ports exposed obviously) - from there, troubleshoot what goes wrong and try again.. repeat until successful.

>>11116 >the Silicone Oil inside of a bladder of sorts This seems like a feasible approach that should be reasonably doable at home. Ofc, introducing liquids of any sort inside our robowaifus brings along some issues that need to be addressed. Leaks will be inevitable at one point or other, for instance. How should one deal with the cleanups for this? Seal maintenance, and reservoir/replenishments? Not attempting to dissuade any anon, but simply bringing up a few necessary points to address.

I've had this idea for a while now, but I was wondering how practical it'd be to run coolant around the body pumped by an artificial heart. I don't mean a real artificial heart, but back in the 60's there was a magazine article about how saltwater can be pumped with a railgun, using magnets perpendicular to the rails to boost the efficiency. I think this is what's used in molten salt reactors. Without any moving parts, you can circulate coolant around the body for realistic human body temperature and can mimic a heart beat sound in the chest just by pulsing the power to the rails instead of flat DC. The coolant would have to be electrically conductive unlike most PC coolants, where leakage could cause something to short, but it could be useful to transmit signals around the body. My biggest problem with the idea is that it needs to be non-toxic, and too much power could cause electrolysis, meaning it could produce either toxic or flammable gas and gradually dehydrate over time. Leaking coolant from a small cut is also a problem if there's no good way to stop it.

>>13165 Not only is this a very interesting idea Anon, but I greatly appreciate your breakdown analysis of the notion's pros and cons. Very helpful stuff for the community here, thanks.

>>13167 Gladly. I only just learned (or re-learned, I might have forgot) about this board, so I've been posting a number of the things I've written and thought about to myself on this subject. I figure that the more I share, the more feedback I can get, but if nobody's interested enough to reply, I'll just put the idea away for later. I forgot to mention the idea that the veins/coolant could possibly be used for infrared light piping if trying to use them as wire is impractical, or maybe serve as both. Due to the "Wiedemann-Franz law" thermal conductors are typically also electrical conductors, and it'd need to be electrically conductive for that railgun pump to work efficiently, so that works out pretty well. Off the top of my head colloidal silver or copper might be the best "robot blood" for this, but I'm sure there's probably some odd cocktail of ingredients that would do the job far better and cheaper, and hopefully without too strong a smell, or being mercury. I also like the idea of it mimicking the look of real human blood, if only because it could help with artificial skin complexion, with subsurface scattering and creating a pink flush/blush. And now that I think about it I don't have much interest in hydraulics for actuators, but if there's already liquids being pumped around in the robot, then it might be worth considering using the robot blood as hydraulics fluid too. If only for the lady bits.

>>13165 How salty would the water need to be? >>13181 Okay, decent idea. However, please keep in mind we want the water not to damage the hoses inside, and being easily disposable through the bathtub or toilet. The materials should also be easiely available. Also, not being toxic or damaging if leaking. Last but not least, the idea was to use it for internal cleaning, so flusing other cleaning agents away, and maybe mixing it with alcohol (after using this one as disinfectant) so it can go into a ethanol fuel cell. Which would return acidic water which could still be usefull for flushing. >infrared light piping I assume this is for internal communication. I was thinking about using led lights for that but in glasfibers or something simpler. We have enough space for tubes and cables, I guess (dependent on the size/type of robowaifu).

>>13183 >How salty would the water need to be? That I don't know. It just needs to be conductive enough, which is why I mentioned colloidal silver and copper, which are relatively non-toxic, are electrical conductors and silver is usually used in heatsink thermal paste anyway. If it were saline made by adding sodium chloride to water, electrolysis could cause it to produce chlorine gas and hydrogen, which is why electrolysis is usually done with baking soda (sodium hydrogen bicarbonate) because it produces hydrogen & oxygen instead. It should be conductive, but need to avoid it being electrolyzed. I really don't know enough chemistry to know what ingredients would be best. All I could do is some brute force trial and error, which would be expensive and time consuming. I would, I mean it sounds kinda fun, but I don't have the time or money for that right now. >Last but not least, the idea was to use it for internal cleaning, so flusing other cleaning agents away, and maybe mixing it with alcohol (after using this one as disinfectant) so it can go into a ethanol fuel cell. I don't like the idea of an ethanol fuel cell in general and don't think ethanol is really compatible with the railgun-pump idea for electrolysis reasons. I don't really like the idea of using the coolant for cleaning either. It should just stay in the body and circulate. Cleaning should be as simple as maybe some soapy water and that's probably not good for making the coolant I was going for. If it is, all the better, but I really doubt it. >I assume this is for internal communication. Yeah, I just figured that if the liquid were clear enough it could double as fiber-optics. I specified infrared because if the skin weren't perfectly opaque then light could shine through it, and you wouldn't notice it if it were IR. Unless you want strobe lights under the skin or something, but I don't.

>>13233 >Unless you want strobe lights under the skin or something, but I don't. >but I don't. <not wanting flashing-light-waifu to go dancing with I like the idea of using internal coolant directly as communications pathways, I admit that's a new idea to me. With the relatively short distances involved, and the absolute brightness of some types of LEDs, that signal degradation could basically be eliminated entirely as an issue for any relatively low-speed (say <= 1 Mbps) comms. Nice one Anon, thanks!

>>13242 I would add that further, at the very least we should be able to use this approach as a sort of "low-speed, back-channel & backup comms buss". BTW, do we have any thread here where exploring this idea further would be on-topic?

>>13181 Glad you made it back Anon. >I figure that the more I share, the more feedback I can get, but if nobody's interested enough to reply, I'll just put the idea away for later. I would encourage you to post your ideas here, regardless of feedback. The board has slowly grown to be something of an archive of Anon's thoughts and concepts of robowaifus, and as such serves the interests of historical posterity at the least. Not that we're satisfied with just that of course! :^) Point being, the 'traffic patterns' of IBs can be quite sporadic, even chaotic, and you never know who will pick up on a good idea at some point and have an 'aha!' moment. Factor in the future anons who will find us and the fact the board is actively archived in different ways, and you have a kind of robowaifu research library of sorts. One I personally consider well worth investing into, regardless of approvals.

>>13281 >still have a number of files saved from http://www.svn.net/krscfs/ at least as far back as 2010 http://web.archive.org/web/20130319004610/http://www.svn.net/krscfs/ >EVO-shooter and Tesla's death ray Sounds like BS. Is this guy in a ward now?

>>13319 Oh, okay. So it seems to have some credibility. I'll download the PDFs then. Thanks.

Crosslink to Solid State Cooling, a new tech which deserves further investigation: >>22730

Today I looked into the filling of cold packs. One of mine broke a while ago and I wondered what this goo inside is made of. I thought it might be some kind of silicone rubber. Instead I found are ways to store heat: https://en.wikipedia.org/wiki/Phase-change_material >Organic PCMs: Hydrocarbons, primarily paraffins (CnH2n+2) and lipids but also sugar alcohols. >Inorganic: Salt hydrates >Hygroscopic materials >Solid-solid PCMs >The most commonly used PCMs are salt hydrates, fatty acids and esters, and various paraffins (such as octadecane). Recently also ionic liquids were investigated as novel PCMs. Fore example: >highly water absorbent >expands when placed in water https://en.wikipedia.org/wiki/Polyacrylamide Useful for things like Thermal Comfort: https://en.wikipedia.org/wiki/Thermal_comfort Waste heat recovery: https://en.wikipedia.org/wiki/Waste_heat Thermal protection of electronic devices: https://en.wikipedia.org/wiki/Thermal_protection Generally, something like these hand warmer pillows (heating pads) which get warm might be a way to store heat, and release it later, without relying on liquid water and the storage "tissue" can still be soft. Some patents to look into (sorry, partially in German): >Patent US2114396: Heating pad. Veröffentlicht am 19. April 1938, Erfinder: Roland Lyman McFarlan, Neck Marblehead, John Bowles.‌ >Patent US2118586A: Thermophoric composition. Veröffentlicht am 24. Mai 1938, Erfinder: John Bowles, Roland Lyman McFarlan (C09K5/06).‌ >Patent DE2917192A1: Mehrfach verwendbares Wärmekissen. (Reuseable heating pad) Veröffentlicht am 6. November 1980, Erfinder: Gustaf Arrhenius (A61 F7/03, C09K5/06) I didn't find an article in the English Wikipedia, but in the German one: https://de.wikipedia.org/wiki/Latentwärmespeicher#Wärmekissen These pads or similar storages are mostly made with: https://en.wikipedia.org/wiki/Sodium_acetate https://en.wikipedia.org/wiki/Sodium_sulfate https://en.wikipedia.org/wiki/Alum https://en.wikipedia.org/wiki/Sodium_hydroxide

Wings! We pump thermal fluids through the robowaifu and then use thin "wings" filled with little tubes as heat exchangers. I took inspiration from how elephants use their ears to help regulate their body temperatures.

>>25300 Yeah I always found thermal chemistry fascinating NoidoDev, thanks! :^) >>25305 Heh, this is in fact a great idea Anon.

Don't think I'd seen the term 'thermoelastic' ITT yet. Particularly interesting was the phrase 'high volumetric energy density'. Presumably this implies a more efficient solid-state cooling system by volume and/or mass. >XJTU latest breakthrough in solid-state refrigeration published in Science http://en.xjtu.edu.cn/2023-05/19/c_893543.htm >=== -minor edit

>>25479 Not sure if it's related: >>22748 but it's also solid-state cooling, I just forgot the hyphen in solid-state.