5 ms·
Researchers have come up with a new way to store electricity in cement
- raydiatian 3y agoElectrified cement? LK-99? Where are the aliens. Who talked.
- LinuxBender 3y agoI am curious, how does this material react to lightning? Does it overcharge and burn up or just stop storing power? One can test this with a long enamel coated wire and a model rocket on a stormy day to induce a lightning strike.
- hnisg4y 3y agoWhy does the lightning hit the rocket instead of an antenna that's a lower height than the rocket? Where does energy want to flow, to a higher concentration of energy or a lower concentration?
- LinuxBender 3y agoThe lightning hits the enamel wire attached to the rocket and flows from positively charged earth to the negatively charged cloud. One can find videos of people doing this on youtube but I do not have any links handy. I am more curious what this does to the concrete as it is not uncommon for lightning rods to be grounded to a grounding rod that is in the building's concrete foundation. I think this should be tested prior to mass adoption.
- hnisg4y 3y agoThe grounding wire would just bypass the concrete into the earth.
- LinuxBender 3y agoThis is not quite true. All ground rods have resistance and are supposed to be tested with a megger and documented to be below a specific ohm rating. With time they gain resistance and some of that energy will be induced into nearby objects, notably anything with electrical properties. In this case we are talking about a concrete that stores and conducts electricity. A lightning strike can be over 1,000,000,000 joules of energy. Some of that will be induced into that special concrete. Regular concrete can heat up and fracture which is mostly harmless but I would like to know what happens with this special concrete.
- hnisg4y 3y agoWell the article says it's made of material that wouldn't catch fire if that's what you're specifically Wondering. Presumably smart people would be insulating the battery from an external surge like a lightning strike. However in practical senses the lightning would go into the rest of the ground as the grounding wire would be bypassing the concrete.
- barbariangrunge 3y agoMy wife's coworker saw a cow go flying into the air last year when lightning struck nearby. Does lightning dissipate perfectly harmlessly when something taller is struck nearby? Actually curious
- hnisg4y 3y agoGenerally yes because the taller person has lower resistance relative to the shorter person. So unless they're connected, lightning would pass through the person with the least resistance to the ground (easiest way to dissipate a voltage difference).
- shagie 3y ago(Aside: https://practical.engineering https://practical.engineering just released a video on "Where Does Grounded Electricity Actually Go?" )
- LinuxBender 3y agoProof he is a time traveler that reads HN. I enjoy his videos. Maybe he can play around with this concrete.
- barbariangrunge 3y agoThe cities are already perpetually under construction/maintenance and still, there's decade-old potholes in some places. Electrified cement: how much more maintenance effort will that take? Are the economic and environmental benefits worth it? It could be Also, if it's a smart city and big tech is involved, think of the scale of the planned obsolescence issues
- wudangmonk 3y agoThis has to be a racket to extract as much public money as possible. At least in the US and in most cities I have been, projects take years and they usually only send a few guys to work on it about once per week. A few years later they suddenly finish everything in a few months.
- mulmen 3y agoAre those workers at home or are they at other job sites with closer deadlines? In other words, is the squeaky wheel getting all the grease?
- TechBro8615 3y agoIn software, projects take years and they usually send a few guys to work on it for eight hours every day. A few years later they suddenly decide to rewrite everything and never finish it.
- freitzkriesler2 3y agoReally it comes down to allocation of (affordle) resourcing and the bidding process construction companies have to do for the cities. Typically the teams you see are being split between several projects and one construction project mnanager is managing several projects. Then throw in city permitting and inspections which take an awful amount of time and expense. Is there a reason it's slow? Yes, they're trying to keep budgets low. However there isn't a reason it needs to be slow. When there's a political will and cultural to do it fast and safely, it gets done. That bridge collapse in Philly on i95 took like 10 days to repair. It also probably cost a lot to repair as well but there was a political will to do it because of how critical that infrastructure is. Same goes for bridges and highways on California destroyed by earthquakes or landslides. Those get rebuilt quickly but the cost to do so is very high.
- tortoise_in 3y agoWhat about flood like situations?
- _Microft 3y agoSee also: "MIT engineers create an energy-storing supercapacitor from ancient materials", 85 comments, https://news.ycombinator.com/item?id=36951089 https://news.ycombinator.com/item?id=36951089
- foota 3y agoAh yes, ancient materials, like graphene.
- dontrustme 3y agoYour average architect is barely managing the coordination of their structural, electrical, mechanical, civil, and plumbing engineers. As green adaptive technology accelerates, it deeply concerns me that our notoriously slow moving construction and design industry will fail to incorporate these technologies and deliver the built environment we need to succeed against climate change. This technology is great, but the real breakthrough will be getting someone like Lennar homebuilders to incorporate this into their constructions by default.
- AlexandrB 3y ago> This technology is great. Not yet it's not. There's a world of difference between using samples of concrete "about the size of a button" and scaling up to something the size of the foundation of a house. And that just gets it to "buildable". To get to "ubiquitous" it also has to be cheap.
- datavirtue 3y agoUse law.
- mistrial9 3y agoanimals and other living things are sensitive to electrical charge in a way that we are not -- sounds more like a useful industrial application, not something to add to a home.
- andrewflnr 3y agoIs the idea here that there are actually two layers of cement separated by membrane? Or maybe more? Anything that breaks up the monolithic cement blob makes it worse at its primary job.
- masswerk 3y agoI guess, this would fail fail on any material properties we use cement for in various flavors of concrete in the first place. Also, the building material is concrete, not cement. Cement is just one ingredient. (It's kind of sad that a publication like Science would mix these up. A road made from cement exclusively would be blown away in a minute. Cement is [just] a binding agent for the aggregate.)
- criley2 3y agoFYI had you read the article, you'd see that they use cement/concrete accurately throughout, and are accurate in their usage of cement in the title. One such quote, although it's throughout the article > The problem is that cement, a primary ingredient in concrete, is normally a poor electrical conductor. So, in recent years, several groups have made structural supercapacitors by spiking cement with highly conductive forms of carbon, such as graphene or carbon nanotubes. Although these perform well, the ingredients are expensive and hard to produce in the massive volumes used in the cement industry, notes Franz-Josef Ulm, a civil engineer at the Massachusetts Institute of Technology (MIT).
- masswerk 3y agoBut, how and why do you jump from what is to all assumptions an interesting surface material to building structures? Also, most capacitors are phono-sensitive, meaning they react to contraction and tension and all kind of vibrations, which wouldn't suggest load bearing masses as a prime candidate for this, even if the doping added to the cement didn't have any effect on the material properties. Let alone the practical problems of having significant charges in any structure, like a road or a building.
- slt2021 3y agoimagine your house catching random fire just like Lithium ion batteries sometimes do while you are asleep. or some random dude (or a tree fall) punctures the wall of your house and sets it on fire
- wduquette 3y agoMy electronics knowledge is extremely rusty; but don't capacitors discharge all at once? Every so often I see another article about using capacitors as batteries, but I've never seen one that addresses the discharge issue.
- seertaak 3y agoYou can just slap a resistor in series, which will induce a drop in potential over it. That, in turn, will mean the potential difference across the capacitor is lower, leading to a more shallow exponential decay of the current over the circuit - ie a slower discharge. And that's just a passive circuit, with an active circuit you have a lot more options. Note: I studied maths and computing so I could very well be wrong. I would appreciate being set straight by elec eng majors!
- kloch 3y agoCapacitors do have a different discharge curve than batteries and this requires more sophisticated power management electronics but nothing too difficult. You basically need a power supply/regulator that can start with much less than rated input current and increase current draw as voltage drops to deliver a constant power output.
- jjk166 3y agoIt takes time for them to discharge, and the rate they discharge can be controlled by the circuit, just like batteries. They just are much less limited in how much power they can handle, so they can discharge the same amount of energy faster. This is a feature, not a bug, as most applications need oversized batteries to handle peak power usage which is substantially higher than average.
- jjk166 3y agoConveniently, the energy density means that 1 cinderblock would hold approximately the same energy as 1 AA battery.
- deltarholamda 3y agoMan, that will turn my Walkman into a Lugman, no thanks, future science.
- getwiththeprog 3y agoSo you could plug in a LED fixture directly to a powered wall block and run overnight, charged by solar fixed to same wall during the day.
- NemoNobody 3y agoThe is one of the biggest technological innovations I have ever read.
- zorrobyte 3y agoThat will promptly be debunked like solar roadways, etc by thunferf00t and others ;)
- pvaldes 3y agochasing bugs about to enter at a totally new level in the history of computers
- jauntywundrkind 3y agoWith what efficiency? >50% of energy returned?
- NegativeLatency 3y agoThey mention roadways, which makes me wonder: Given that this has so much carbon black in it how much more solar energy would it absorb that would normally be reflected. Not many pictures but the samples look quite dark: https://www.pnas.org/doi/full/10.1073/pnas.2304318120 https://www.pnas.org/doi/full/10.1073/pnas.2304318120
- Ekaros 3y agoHow practical this would be? Considering use cases of reinforced concrete and like? Or how sound structurally it would be compared to what we currently use? We use reinforced concrete for reasons. And if this stops it from working is it really worth the effort?
- moomoo11 3y agoDumb question (please don't mad) Why don't we put springs under massive buildings like skyscrapers that anyway move a little bit with wind? Maybe the millions of tons compressing the springs a little bit could result in some electricity? Or under roads and airport tarmac?
- function_seven 3y agoFor the swaying buildings, you'd almost certainly not get enough power out of it to make it worth the cost and additional complexity to install. For roads, whatever power you generate from the traffic would be less than the additional power those cars require to drive on your road. It would be a net loss. Basically generating electricity from gasoline, with extra steps.
- jokoon 3y agoShouldn't moderators remove this? This is not /r/upliftingnews or /r/futurology. I know I'm being grumpy and highly skeptical, and that Y combinator is about innovation, but why not make a hackernews to compartmentalize those things? I would be okay about a paper that discuss feasibility instead of the usual "maybe yes? maybe no." blogspam.
- dang 3y agoHN's only criterion is whether something is intellectually interesting. I don't see why we should remove this one - but I do think the baity title could be replaced (this is in the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html), so I've replaced it with a more representative sentence from the article.
- lloydatkinson 3y ago> electrified roadways could power electric cars as they drive Here we go again, SolarRoads…
- Animats 3y agoThe article is all hype.[1] The paper isn't much better. There's a bullshit "Significance" section at the top. Most of the "references" are to generic papers about energy. If there's a watt-hours/kilogram value, the number that matters, I can't find it. Here are Wh/Kg values for known ultracapacitors.[2] Numbers are in the 4 to 15 range. Where is this new thing? [1] https://www.pnas.org/doi/10.1073/pnas.2304318120 https://www.pnas.org/doi/10.1073/pnas.2304318120 [2] https://en.wikipedia.org/wiki/Supercapacitor https://en.wikipedia.org/wiki/Supercapacitor