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[dupe] A clear, strong, and thermally insulated wood for energy efficient windows (usda.gov)
99 points by bookofjoe on Oct 4, 2020 | hide | past | favorite | 47 comments




> The wood is oxidized in a special bleach bath and then penetrated with a synthetic polymer. The resulting material is not only virtually transparent, it acts more like plastic.

As someone commented in a previous thread, it is essentially wood fiber reinforced plastic. It would be interesting to compare it with other plastics commonly used instead of glass, like polycarbonate.


It sounds unrecyclable, and unreusable.


Most material waste from a home renovation is tossed into the local dump. It is rare anything is salvaged.


Yeah, but to be fair, windows tend to be used in roles where they last a very long time.


Why would you need to recycle wood? It's biodegradable and cheap.

Recycling is overrated for cheap products. Plastic is practically impossible to recycle effectively. If it were made to be biodegradable that would make much more sense. But even failing that, there is no shortage of landfill space, as long as it goes to the garage and not to the environment - a huge problem in the developing world and where the plastic in the ocean originates from.


Wood is biodegradable. If mixed with plastic however (which this seems to be), it's not.

While it's relatively easy to recycle pure plastics for composite materials it's notoriously difficult.


This plastic, PVA, is the one used in white glue, the one that kids use in school or carpenters use to glue things together. Wikipedia [0] says it biodegrades slowly. I believe (keyword: believe and am not sure) it could be redissolved in warm water, or might even be replaced by a renewable glue like gelatin.

[0] https://en.m.wikipedia.org/wiki/Polyvinyl_alcohol


Not sure you'd want a window that easily dissolves in water...


To help others parse the last paragraph, I would add a comma because clauses:

While it's relatively easy to recycle pure plastics, for composite materials it's notoriously difficult.


*between clauses I meant to say


Neither is glass, which I'd hazard lasts longer in the environment as well - although glass at least doesn't float so it can't "wander off".


Firstly, it is a natural material - its basically sand. It does as much damage to the envirobment as any random rock.

Secondly it has been recycled for decades and is actually a relatively simple material that can be molten, purigied abd re-cast, much like metals can be.


However glass is inert, whereas plastic is not


Apparently if you dump glass into the ocean, within 10 years it looks like those decorative pebbles so it's actually a pretty good way of dealing with it.


Now imagine dumping a million tons of it at a time, in a few select spots of the ocean. That’s what we did with plastics.


No.


Recycling wood products is actually quite environmentally unfriendly and produces inferior products. It really only makes sense to recycle glass.


> It really only makes sense to recycle glass.

And metals like aluminum, iron, copper, etc.


The thermal conductivity of the polymer is pretty close to the thermal conductivity of their window[0]. It looks like literally any fiber with an appropriately balanced fiber size v. refractive index difference would do the same job.

If you were going to support this between two panes of glass for waterproofing, you might as well just use the PVA and skip the wood, as it will likely be much cheaper eliminating the harvesting, rotary cutting, delignification, and impregnation steps. Or, you might even put nothing between the two panes of glass, since air is a good insulator as well.

[0] https://pubs.acs.org/doi/pdf/10.1021/acs.macromol.5b02477


Vacuum-insulated glass exists too. Better than air but trickier to work with.


Err plexy glass and similar materials have been around for quite some time. They have a major problem though. They scratch easily!


>A Clear, Strong, and Thermally Insulated Transparent Wood for Energy Efficient Windows

https://onlinelibrary.wiley.com/doi/10.1002/adfm.201907511

>Transparent Wood Could Be the Window of the Future [U.S. Department of Agriculture]

https://www.usda.gov/media/blog/2020/10/01/transparent-wood-...


Very interesting (as a new material).

It being not waterproof/waterresistant (unless painted) doesn't seem to make it a good glass replacement for windows, though.

Possibly as an inner pane(s) of sealed multi-pane windows (with traditional glass on the outside) as - also - since it can be cut with ordinary rotary tools, it probably is not scratch resistant.

The light weight seems to me like the most relevant feature.


> It is approximately five times more thermally efficient than glass, cutting energy costs.

Seems even more useful than its weight. There is a lot of energy loss from the windows of buildings. Would be a huge gain if that can be brought down significantly.


You have to factor in the usual lifespan of glass as compared to this. A clean glass pane will resist water and ice for hundreds of years. This stuff will need to be repainted every few months to keep integrity.


I honestly do not understand why I m getting downvoted here. Am I saying anything untrue? Or did I only find a flaw which is not mentioned here?

Imagine leaving a house unattended in a humid or rainy area for one year, you would come back to swollen up windows which I am sure are far from clear. I guess you would have to replace these windows at least 5-10 times as often as regular glass. Also, glass is 100% recyclable whereas this would produce even more plastic waste.


It sounds like they’re comparing it to single pane glass, which is not what most windows are made of these days when thermal efficiency is a concern.


Well it's one to one, it's a single pane of this stuff to a single pane of traditional glass. Nothing says you can only use a single pane of this new material.

Someone mentioned that this isn't weatherproof, but it could still be used for the inside plies of a triple glazed window for instance.


Multi-pane windows are great thermally, but they need to be replaced when the seal breaks and they get filled with condensation. If this material addressed that issue, it might make longer-lasting multi-pane windows?


Not a big issue, they last for decades nowadays


Or, have it sealed in the middle between two panes of glass, giving you water and abrasion protection. If you could glue it together, the glass can be super thin.


>Or, have it sealed in the middle between two panes of glass

Yep, not much different from:

>Possibly as an inner pane(s) of sealed multi-pane windows (with traditional glass on the outside)

I mean, what is the "Or,"?


Your original sentence is hard to understand, so it is being ignored.


Glass/glue/wood Vs Glass/air,vacuum/wood


I wonder if this is the same material I've recently come across as transparent containers sauces and the window in cardboard packaging, which are supposed to be "industrially compostable".


Cellulose films are supposed to be in this category but I've never understood how a consumer is supposed to distinguish it from plastic


The recycling label, presumably.


Those are likely just plastics.

Some of them might be PVA (though water solubility isn't really a great feature for packaging).


They say they're made from vegetable material (for the containers, I think) and wood for the window, but I don't know what that actually means, of course.


I meant the containers are just plant based plastics, with no wood in them. There's a whole bunch of processes to derive plastics from plants:

https://en.wikipedia.org/wiki/Bioplastic


Yes, ultimately I suppose all(?) plastics are from plants, possibly via geological processes. I don't know what the legal definition would be, and the packaging which says "plastic free" might well contravene it, but at least it's (apparently) compostable.


> Glass production in construction also comes with a heavy carbon footprint. Manufacturing emissions are approximately 25,000 metric tons per year.

Actually I think it’s closer to 50 million tons (0.5 tons of CO2 per ton of product times 100m tons of flat glass per year).

Relatively we’re talking about ~0.1% of worldwide emissions. Glass production used to emit closer to 1.3tons/ton, but it’s gotten a lot more energy efficient over time.


there's a few videos from years ago attempting earlier versions of this[0]. In the end, it is very little "transparent wood" and more "plastic with wood bits in it".

[0] e.g. https://www.youtube.com/watch?v=x1H-323d838


PVA fibers get weak when heated (read: typical Texas summer) I wonder how this will perform with the wood cellulose.


They don’t mention cost compared to glass?


I thought it was suppose to be transparent aluminum we got in the future. Scottie!




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