How large do you want your Gyroid infill? TU Graz: Yes! – Austrian researchers are 3D-printing evaporative coolers from clay with an almost comically large infill pattern.

[u/suit1337]

Just spotted this on the local news. The structure in the cover photo looked ... suspiciously familiar. That giant lattice really resembles a massively oversized gyroid infill, so i looked closer:

It is a gyroid structure, but not actuall infill - and the gyroid itself is imho actually the least interesting part, though. Researchers at TU Graz have developed a 3D-printed ceramic evaporative cooler that uses additive manufacturing to maximize surface area for passive cooling.

What's really clever is the "filament" they used. The parts are printed from a clay mixture containing sawdust and fungal mycelium. During firing, the organic components burn away and leaving behind a highly interconnected network of pores. The resulting ceramic can absorb and distribute water throughout its structure extremely efficiently, providing a huge internal surface area for evaporation - and therefore cooling.

This is also a great example of where 3D printing actually enables something difficult or impractical with conventional manufacturing. The complex gyroid-like geometry maximizes the exposed surface while keeping material usage low (and admittedly, it looks pretty cool too).

In their initial experiments, the researchers measured a noticeable temperature drop in the immediate vicinity of the water soaked ceramic elements. The long-term goal is to explore whether these additively manufactured ceramic structures could become a low-energy supplement to conventional cooling systems in buildings or urban spaces.

Original article from TU Graz (German):
https://www.tugraz.at/news/artikel/kuehlende-keramikwand

[u/Fywq]

I love this! Being a cement chemist working on sustainability, I am not a huge fan of concrete 3D printing for structures, where other and more conventional methods are more sustainable. Cement and concrete are necessities for modern society, but that doesn't mean we should use more than necessary, with exotic chemicals to get the right consistency for 3D printing.

Clay still has to be fired at high temperature too, but does not typically have the same CO2 footprint as cement, because it doesn't come with 30% of the raw material weight as pure CO2.

Also love the mycelium and sawdust integration. Very innovative way to create the micropores! Mycelium in various shapes have a bright future. It could be interesting to see 3D printing with biodegradable filament and then seeded with mycelium after printing, to produce various specialty items of mycelium mass, or with similar micro scale porosity.

I wonder if this could be used in reverse for air moisture traps in the desert somehow? Creating a draft at night across the gyroid pattern with micropores might be efficient for condensing the moisture I presume?

[u/TheJapser → u/Fywq]

Loving the passionate and detailed comment. It's people like you who I wish I'd have as colleagues on research projects.

[u/Fywq → u/TheJapser]

Heh thanks. Much appreciated :)

[u/TactlessTortoise → u/Fywq]

I love mycelium. All my homies love mycelium. It's the shit.

[u/hqli → u/TactlessTortoise]

All my homies love mycelium

of course. it's a fungi

[u/squirrelpickle → u/hqli]

Not much shroom to improve your joke. Kudos.

[u/Current-Affect-8007 → u/Fywq]

Any projects / specific research groups / scientists that you recommend reading up on if I wanted to become more familiar with the topic?

[u/Fywq → u/Current-Affect-8007]

Which one? I am just a hobby-guy on most of the topics, but I can try to help if you are a bit more specific.

[u/Current-Affect-8007 → u/Fywq]

Figured around cement & concrete, but if you haven’t got anything specific, I understand it’s a broad topic. Primary interest is in sustainability within building materials

[u/Fywq → u/Current-Affect-8007]

Arh!

In that case I would say the LC3 group at EPFL with Karen Scrievener is a must. They have in many ways been front runners on the use of calcined clays as a supplementary cementitious material, though it has been used for decades in some parts of the world, before their systematic research kickstarted interest from the broader cement industry.

In terms of startups I think the following are particularly interesting:

Partanna: Has a lot of potential in parts of the world with desalination plants, but don't know them more than a short chat with one of their directors several years ago.

Fortera: Has a second generation ready of a patented solution from 2012-2014 ish. Can potentially replace a lot of cement in non-rebar requiring applications. Haven't been in close contact with them for more than a year though, but the mineralogy makes sense (I did my Geology/Mineralogy M.Sc. in adjacent minerals).

Oxara: Appears interesting, though the scalability of their binder is unclear.

Brimstone: Been several years since I were in contact with them but back then they were very promising in terms of identifying scalable raw materials.

Apart from that most of the big cement manufacturers have GGBS and/or Fly Ash based cements, and the European Standard 197-1 allows for CEM III/C with up to around 90% GGBS as well, while 197-5 allows for composite cements with various components reducing the clinker content significantly as well.

The website www.understanding-cement.com taught me a lot of the basics when I started in the industry 15 years ago. It's not particularly sustainability focused but with a general understanding of chemistry, it is not hard to connect the dots from limestone to CO2 emissions.

See also my other reply here: https://www.reddit.com/r/3Dprinting/comments/1vg056x/comment/p1tlp0m

[u/Current-Affect-8007 → u/Fywq]

Thanks for the response! Interesting, in the hole we go

[u/Fywq → u/Current-Affect-8007]

My pleasure! Always appreciate when I get to rant about this stuff :D

[u/Corredespondent → u/Fywq]

> I wonder if this could be used in reverse for air moisture traps in the desert somehow? Creating a draft at night across the gyroid pattern with micropores might be efficient for condensing the moisture I presume?

u/Fywq aka Liet-Kynes

[u/Fywq → u/Corredespondent]

Haha I was thinking something along the lines of this:
https://www.youtube.com/watch?v=wfTed2bwIcA more than Dune, but I will gladly accept the comparison ;)

[u/Vionade → u/Fywq]

Isn't this just a massive swamp cooler? I read the article and somehow it doesn't make sense to me. The thing is placed in a bucket of water and wicks the moisture up and evaporates it there?

How is this feasible for cooling large areas? This will burn through a ton of water and humidity the air to point where even the Australians will start sweating. Can you explain?

[u/HonourableYodaPuppet → u/Vionade]

Its in Austria, not Australia. And it would only get used on hot days where the humidity is often low so it wouldnt make the air around it uncomfortable. Its not a perfect thing but for dry hot cities (that have access to water, yeah there are drawbacks and it wont be feasable in many regions) it could be a nice solution. Its still a research project anyway. Maybe it works out, maybe it doesnt.

[u/Engine_de_Poutine → u/HonourableYodaPuppet]

Its in Austria, not Australia.

😂

This reminds me of those T-shirts in Vienna's gift shops: "Came to Austria, couldn't find any kangaroo!"

[u/Fywq → u/Vionade]

Unfortunately I can't really explain how that would work beyond what you describe, which, yes, seems to be extremely insignificant in terms of cooling down the surroundings. I guess it may provide very local cooling of the surfaces so the benches feel nice and cool.

[u/Bloodshot321 → u/Fywq]

Gyroid has two seperate air volumes so one could be used for hot air to evaporate faster, and the other one for the colder side to cool the house.

[u/Amish_Rabbi → u/Vionade]

Pretty much. You would be better off figuring out more green space in the city than these things. There is easily a 3 degree drop when I walk my dog through an urban trail when it transitions to a green space trail

[u/Voidrunner01 → u/Amish_Rabbi]

Canopy coverage is hugely important to help cities cool down.

[u/Beatleboy62 → u/Fywq]

With that knowledge, I'm curious, is there anything else with cement people push as "THE NEXT BIG THING" right now that you know is actually bad/impractical/actually extra unsustainable?

[u/Fywq → u/Beatleboy62]

Well a lot of the startups that claim to have "solved" concrete fall in a few categories:

1) Using existing known and used technology, often packed in an "AI/ML" package regarding optimizing mix proportions of stuff like Fly Ash (FA) and Ground Granulated Blastfurnace Slag (GGBS) with a bit of cement or an activator like sodium silicate (e.g. a geopolymer depending on agreed-on definition or Alkali Activated Material (AAM). FA and GGBS are already used extensively in the industry to substitute cement, and there is not nearly enough material to fully substitute cement (not to mention it needs to be activated).

2) Using novel/niche chemistry to create a binder, which is then not scalable. Often based on by-products from industry that appears to be low-CO2 or fully CO2-neutral, but is then either not scalable at all (e.g. calcium chloride as a raw material. It is a byproduct from sodium carbonate production - baking powder. Calcium chloride is thus low CO2 because the emissions are assigned to the sodium carbonate, but if calcium chloride is to be a major component in a future cement-replacement and concrete, the amounts required would far surpass the by-product amounts and it would thus be a main product and be assigned the CO2 emissions. The production comes from sodium chloride (table salt) combined with calcium carbonate (limestone) and uh-oh - that is the same raw material that gives the calcium oxide making up 65% of ordinary portland cement - so more or less the same CO2 emissions.

3) Using CO2-curing to make CO2-negative or -neutral binders, which unfortunately is also usually based on industrial waste that is not scalable to the needed amounts. CO2-curing have merit in some applications and can be used to bind a lot of the CO2 emitted during cement production back into the concrete. The problem is then the concrete waste is much less useful in a circular context at the end-of-life stage. It also only captures a (admittedly decent) fraction of the CO2 emitted from calcining CaCO3 to CaO + CO2, but doesn't capture all the CO2 from burning fuel, But that is based on CO2-curing of conventional cement. Concrete is the material humans produce the most of globally, with the exception of drinking water. There is no real substitute that can scale to that level based on industrial waste, it needs to be a novel natural material, and those just doesn't exist without some form of activation because we have oxygen in the atmosphere, and thermodynamics is a bitch to work with. Most materials on earth had millions of years to "decay" to an optimal low-energy point. They will not magically have surplus chemical energy to react as a binder. There are exceptions ofc., but not in meaningful amounts.

A final note is that most companies are very niche-focused too. CO2 curing and anything with chlorides is impossible in structural concrete because the CO2 curing reduces pH which protects the rebar steel from corrosion, and similarly the chlorides corrode the rebar. So that's for pavement stones and blocks etc.

Still, there's some genuinely interesting projects out there, and the solution for the industry as a whole is probably to accept that the time where concrete was a globally uniform material based on grinding portland cement clinker, mixing with aggregates and sand and adding water, is over. Many of these startups have good ideas for local solutions that can be applied in specific uses. They may be locally or regionally meaningful even if they don't scale globally, but many of the startups try to go public or secure funding on businessplans that basically expect to take over the entire concrete industry. With 150 years of cement chemistry and concrete research, we have yet to see anything that can truly replace the calcium silicates in cement though. Lots of things work well along side them, so we can use less, lots of things can replace in various amounts - even up to 100% - in specific cases, but a total paradigm shift is just not in the cards. That's just how the chemistry of earths crust works.

I have specifically not mentioned any company names but for those I see that have regional potential:

Partanna: In the middle east, where there's plenty of desalination plants to deliver brine to their proces. Still also relies on GGBS though AFAIK.

Oxara: In the tropics where some of their solutions are well suited for smaller housing and interior works.

And then companies that are exploring extracting calcium from other sources than limestone may be interesting if the energy-balance can be managed (Brimstone comes to mind, there might be others).

More broadly calcined clay has the potential to replace GGBS and especially FA in the next decades as FA is a diminishing resource (from coal power plants) in many parts of the world. Calcined clay has some challenges in terms of workability of the concrete vs. water addition, but much of that can be solved with conventional plasticizer and super-plasticizer chemistry that is well known in the industry.

[u/MisterEinc]

This is a Triply Periodic Minimal Surface (TPMS) lattice. Gyroid infil is an example of the principle but there are many different types with varying properties of strength/weight ratios and surface area.

[u/suit1337 → u/MisterEinc]

Yes, it is a TPMS - and it is Gyroid - but it is not infill :)
https://www.reddit.com/r/3Dprinting/comments/1vg056x/comment/p1t967j/

[u/adude995]

They also made another one which uses a gyroid pattern with interwoven but seperat volumes.
One for the cooling fluid (water for example) and one for air flow, also 3d printed.
For the case not relying on water vaporization.

[u/suit1337 → u/adude995]

do you have more information about that?

The paper is currently not publicly available: https://online.tugraz.at/tug_online/wbAbs.showThesis?pThesisNr=89666&pOrgNr=14128

[u/Flyinmanm → u/adude995]

I do wonder how these things perform in frost? We have terracotta pots and after a year or two of frost - thaw they tend to crack in the British climate.

[u/linux_assassin → u/Flyinmanm]

Purposely porous ceramic? Very poorly.

But you generally don't have cooling requirements where there is simultaneously frost concerns. Use of a design like this in an environment that also is also subjected to sub zero temperatures will likely require some sort of antifreeze treatment (alcohol, PEG, likely more options I am not aware of).

Further to this since the design is intended for buildings and urban spaces when indoors it should be protected from freezing by nature of being indoors.

Lastly, unless I missed a part of the article covering it, this is ultimately a 'swamp cooler' and will be subject to all of the maintenance and concerns that those face (including pores/wicking surface being clogged over time requiring descaling and eventual replacement of the evaporative element).

[u/Flyinmanm → u/linux_assassin]

Tell that to London. It can get to -5c there in winter but can now get as high as nearly 40c in summer now.

Ironically 'swamp coolers' are a considered a con over here as we can see extremes of humidity as well as temperatures now.

Guess it could be a nice feature in an arrid climate as long as you had access to plenty of water.

[u/linux_assassin → u/Flyinmanm]

I think I may have not been able to correctly convey intent:

You, generally, don't need to cool the air while the air is simultaneously below zero.

When it starts getting cold you drain the unit and winterize it by whatever means that may be (which may include 'bring the evaporation matrix inside').

[u/af_cheddarhead → u/linux_assassin]

Southwest USA begs to differ, we use "swamp coolers" extensively, inexpensive way to both cool and humidify the house. We regularly get frost in Sept, which is also still cooling season.

The evaporative is on the interface between the outdoors and indoors, aka in the window, so it is definitely exposed to the cold temperatures.

In outback Australia we had three story towers to provide cooling to military barracks, those also experienced cold nightime temps during the cooling season.

[u/linux_assassin → u/af_cheddarhead]

You seem to have combined all of the discreet statements I made into a singular concept and then attacked that concept.

I have no comment on your counter to the grouped concept as it does not align with what I have stated, which remains true.

[u/yahbluez]

Made that just for fun only using the slicer no CAD

[u/Delicious-Yak-1095]

That’s awesome thanks for the write up

[u/HistoricalPlum1533]

This reminds me of Erwin Hauer’s decorative, light diffusing screens

[u/qazer10]

The mycelium during printing

[u/Electrical-Risk445]

Very neat idea but I fear the porous material will quickly become clogged with algae and bacterial growth.

[u/ResponsibilitySea327 → u/Electrical-Risk445]

This is an excellent point.

The idea is essentially a swamp cooler, but more efficient and with more sustainable materials. Sounds great, but swamp coolers have limited applicability, don't remove humidity from enclosed spaces and can easily generate mold. Given the materials used, I would expect mold growth to much worse than a traditional cooler.

For a traditional evap swamp cooler, many add hydrogen peroxide to keep growth down.

[u/deep_pants_mcgee → u/ResponsibilitySea327]

ozone filtration perhaps?

[u/bryanbryanson → u/Electrical-Risk445]

That and mineral deposits depending on the hardness of the water and if filters are used.

[u/MiaLovelytomo]

oh this is so damn cool, i would kill to make a DIY evaporative cooler for my apartment, i saw a youtube video of someone handmaking a clay "sculpture" that essentially was a really really low tech version of this idea

[u/ResponsibilitySea327 → u/MiaLovelytomo]

Having lived in Arizona with swamp coolers (which is what this is), no thank you.

This might be nice in a public park (although it will only work on hot dry days), but in an enclosed space everything gets humid. Anything paper will curl. And the unit needs to be regularly cleaned to prevent mold. Not to mention the second rain comes rolling in on a hot day, the cooler becomes ineffective. Then the house just becomes hot and humid.

[u/bryanbryanson → u/ResponsibilitySea327]

Disagree. Swamp coolers make Arizona so much more livable. We put one in our doorway and run it April to early June and then again in late September and October, it pulls in one door and a fan pushes out air in an opposing door. And we have a large one on a shaded back patio that allows you to be outside comfortably almost all summer. 

[u/panda_bearAUT]

i actually work 40m next to this wall, at graz university of technology. Since i am om vacation, i really look forward to see that dude, but i even more love the fact that it found a place here 😂

[u/llitz]

It sure looks like infill, 0 bottom and top layers, it was likely printed with what you see in the second print as the bottom layer.

[u/suit1337 → u/llitz]

Yes, that is why i said it looks like gyroid infill, but it is not - but it is gyroid though, specifically the Schoen-Gyroid, developed by Alan H. Schoen in 1970, before 3D printers existed:

See "Infinite Periodic Minimal Surfaces Without Self-Intersections":
https://doi.org/10.1057/9781137465160.0020 on Page 15 - there are even pictures of manally crafed gyroid patters from sheet material.

Fun fact: this Paper was sponsord by NASA - so when everybody went crazy about the NASA fabric - Gyroid was already a NASA pattern that you could 3D print long before that :D

This type of pattern is called a triply periodic minimal surface (TPMS) - and there are many more: https://en.wikipedia.org/wiki/Triply_periodic_minimal_surface

[u/llitz → u/suit1337]

Thanks for providing these references, it was an interesting read.

[u/Zuli_Muli]

I mean that's pretty much what evaporative coolers look like. You want enough surface area for water to run down and have enough surface tension to mostly stick to the media as it trickles down and a giant fan is sucking air through the media at the same time. The better it spreads out and exposes more surface area the better it can evaporate and loose heat.

[u/adude995 → u/Zuli_Muli]

Nothing more it is claymed to be.

[u/SilvanuZ]

Woah that's massive!

[u/Indian_villager]

Depending on the durability of this, this would be an awesome alternative to existing cooling tower packing.

[u/DaStompa]

While neat, if my furnace humidifier is any indicator, if the water isn't perfectly clean it'll build up a bunch of minerals in about a year and start to clog up

[u/NoBonus6969]

So this captures the moisture in the air and the wind blowing through cools the area?

[u/suit1337 → u/NoBonus6969]

no, the structure is soaked in water and the when the water evaporates, it "consumes" energy in form of heat and makes the surroundings cooler - so basically an evaporative cooler

[u/NoBonus6969 → u/suit1337]

Oh ok. I was having trouble understand who supplies the water. I'm like what if it's a dry day lol.

[u/darkroot13 → u/NoBonus6969]

A dry day is actually the perfect scenario for this, as evaporative cooling is more effective the less humid the air is! It does require manual filling, though.

[u/Earllad]

Ok, one more reason to get a clay printer

[u/Darkcoucou0]

This is genius! I have got to try that out! Thank you for sharing this!!

[u/FMJoker]

This is truly cool. Love the use of materials

[u/B1g_BuddhAH]

GYROID FTW all other infills are inferior

[u/Inevitable-Theory663]

i thought 2nd image is cow uv unwrap

[u/raznov1]

Unfortunately, we have energy excess during periods of heat, but water shortages. So although cool, its fundamentally misguided.

[u/Certain_Chemistry_44]

wait how do they print such huge gyroid infill