Cool it, Woody

May 26, 2019 10:26 AM

Boiled in hydrogen peroxide, soaked in fluorosilane and densified in a press, wood can be really, really cool. Like, below ambient cool.

"One good way to reduce the amount of cooling a building needs is to make sure it reflects away infrared radiation. Passive radiative cooling materials are engineered to do this extremely well. Li et al. engineered a wood through delignification and re-pressing to create a mechanically strong material that also cools passively. They modeled the cooling savings of their wood for 16 different U.S. cities, which suggested savings between 20 and 50%.

posted by seanmpuckett (18 comments total)

Ars Technica's story on it:

Stronger than aluminum, a heavily altered wood cools passively
Boiled in hydrogen peroxide and compressed, the wood can passively manage heat.

posted by XMLicious at 11:17 AM on May 26, 2019

Honey, get me my bark shield, I'm going into town!
posted by Oyéah at 12:30 PM on May 26, 2019 [4 favorites]

The English language has a word for wood that has been delignified and then re-pressed: “Paper.”

So. Is. This like. A wood semiconductor??

No.

For one thing, thermal conductivity is not electrical conductivity. For another thing, this treated wood paper has less thermal conductivity than regular wood.
posted by Sys Rq at 1:28 PM on May 26, 2019 [1 favorite]

For another thing, this treated wood paper

Nice work being snotty and everything, but the properties of the product are coming from the fact that the cellulose is in the same structure it is in the wood, modulo some amount of recrystallisation.

The ars writeup is pretty interesting. And there's no reason to think we won't be seeing this in use before too long.
posted by ambrosen at 1:59 PM on May 26, 2019 [5 favorites]

Do you still have to paint it?
posted by Huffy Puffy at 2:12 PM on May 26, 2019

Painting it will stop it radiating the heat, so no. It's weatherproof from the fluorosilane.
posted by ambrosen at 3:05 PM on May 26, 2019 [1 favorite]

I am uninformedly alarmed by fluorine chemistry, so extra props to working out a process with it.

How amazingly clever to find something that radiates at the transparent bands in the atmosphere. Anybody here know of a ... list or estimate for how warm a climate has to be before a building of a given size has cooling load but no heating load?
posted by clew at 3:16 PM on May 26, 2019 [3 favorites]

More importantly, will termites eat it?
posted by halfbuckaroo at 3:23 PM on May 26, 2019 [1 favorite]

More importantly, can you dovetail it?
posted by ActingTheGoat at 4:55 PM on May 26, 2019 [3 favorites]

clew, it doesn’t have to be that hot for certain kinds of occupancies. In many temperate areas office buildings are cooling-predominate for more than half of the year due to the internal heat gain from people, computers, and lights.
Here’s a good primer for the UK, which shows an office building is cooling-dominated in that region for about 6 months out of the year. Where I am, in Southern California, it’s closer to 9 months.
posted by q*ben at 5:04 PM on May 26, 2019

... although using heating degree days as a metric you have to get pretty close to the equator before you hit zero.
posted by q*ben at 5:08 PM on May 26, 2019

Probably at least as termite resistant as pressure-treated timber.

Cool that the process mostly involves hydrogen peroxide.
posted by aspersioncast at 5:13 PM on May 26, 2019

Nice work being snotty and everything, but

When you remove the lignin from wood, it is no longer wood; it is cellulose mush. When you compress the cellulose mush into a product, that product is called paper. That’s just a fact. I’m deeply sorry if this fact offends you.

If I were trying to be snotty, I’d’ve pointed out that, “A very thin graphite coating is applied on both faces of the samples,” sure sounds a hell of a lot like a roundabout way of saying, “We scribbled on the paper with a pencil.”
posted by Sys Rq at 8:34 PM on May 26, 2019 [1 favorite]

Well, in the paper, they’ve said it has the tensile strength higher than steel, but in a quick rescan, I didn’t see how big the bits of wood were that they used for tests, so I don’t know if this is a process which is applied to structural components, Like 2x4s, or if, as SysRq suggests, this is a thin cladding which is an exterior element. However, I haven’t read the Ars article yet, so perhaps they go in to use application.
posted by SecretAgentSockpuppet at 7:18 AM on May 27, 2019

Heh.

But at least from the Ars article it seems that one of the defining characteristics of the process is that the finished product retains the cellulose latticework of the existing piece of wood - no cellulose mush stage.
posted by aspersioncast at 7:21 AM on May 27, 2019 [1 favorite]

That's cool if you think I'm too stupid to know the difference, Sys Rq.

For everyone else, yes, the technology is interesting, and that's why Science published the paper.
posted by ambrosen at 9:27 AM on May 27, 2019

All I said was “hey guys this sounds a lot like paper,” and you said I was snotty. Yeah, clearly I’m the asshole in this situation.

I don’t think you’re stupid and never said you were — I have no idea who you are and couldn’t care less — but I do think you’re being obnoxiously confrontational, and I hope never to interact with you ever again.
posted by Sys Rq at 12:53 PM on May 31, 2019

Like I said, it's interesting technology, and worthy of a paper in Science.
posted by ambrosen at 2:45 PM on May 31, 2019