Solarpunk technology

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perestroika , in New MIT Discovery Just Solved one of Physics BIGGEST Mysteries! - YouTube

Thanks for the news, but also - thanks for posting a proper summary. :)

(So many videos have only the YouTube-compiled summary, which is typically totally off topic.)

taanegl , in What Will Life Really Be Like After The Internet Gets Incinerated?
@taanegl@beehaw.org avatar

Those of us who know how to write cursive will run thungst, mostly because nobody would be able to read what we write lol

The world would be run by doctors, is what I'm saying.

keepthepace , (edited ) in When It Comes to the Environment, There Really Is No Such Thing as a “Good” Car

That’s according to a peer-reviewed study funded by the Ford Motor Company, a company that makes most of its profits from gas-powered vehicles.

If you want to see if a tech is part of a renewable future, it is direct emissions that should be counted. EVs are at zero. They don't emit CO2 when running, when being produced or when being disposed of. They use electricity and transport, two things that we can provide without emitting CO2. They are a piece of the puzzle of a sustainable society, something thermal cars will never be, and something these graphs hide.

Of course we will be better off without cars and trucks, but the road towards them being totally gone is long, and it is time we don't have.

benjhm , (edited ) in When It Comes to the Environment, There Really Is No Such Thing as a “Good” Car

Even if we had low-emissions, low-noise, low-accident cars, there'd still be the concrete jungle surface needed to drive them - and loads of emissions to make the steel and cement of highways.
Although cars carrying four or more people directly to a medium-distance destination can be relatively efficient per pers-km, people buy oversized cars imagining some dream holiday, then use them for daily life on one-person trips that (electric-) bicycles and/or trains could do - car-sharing could help avoid that and solve the EV-range issue (although personally, my dream holidays would be in places with no cars at all).

HollandJim , in Tesla partners with BYD's FinDreams for energy storage Megafactory in Shanghai - ArenaEV

Great for batteries, and yes - trying my best to ignore Tesla, et al.

And for folks looking for home systems, EG4 is killing it with their hybrid systems. A couple big wires and it’s done! Not affiliated in any way, but check out this ~$3400 14.3kWh plug-and-play battery. Noice!

7U5K3N , in freesewing.org - software that adjusts sewing patterns to your exact measurements

How spiffy! Thanks for the link!

I've passed it along to a few other folks I know that sew!

guillem , in freesewing.org - software that adjusts sewing patterns to your exact measurements
@guillem@aussie.zone avatar

For all those people so abundant on Lemmy that love plush sharks, they have a pattern to sew that.

plenipotentprotogod , in Fairphone 4—the repairable, sustainable smartphone—is coming to the US

I'm a big fan of upgradable hardware, but lately I've found that the bigger problem with Android phones is the lack of software support. I had my last phone for 5 years and finally upgraded not because there were any major hardware problems, but because the android version was so far out of date that I was starting to feel the pain of missing out on some major improvements, plus some apps actually were starting to break. I picked my current phone specifically because Samsung was promising to support four major version upgrades which is, unfortunately, industry leading among Android OEMs despite lagging hugely behind Apple's software support for their older models.

Fairphone seems to have a mixed track record on this. According to their website the Fairphone 2 got 5 major updates (great!). But the Fairphone 3 got only one update (bad). And the fairphone 4 has received one update so far with a second one promised. After that they say that they'll try to provide two more updates, but they're not making any promises because the processor will be out of support with Qualcomm by then.

This is, unfortunately, a very understandable position to take. The fact that Android OEMs rely on third parties like Qualcomm to design and support their processors is definitely the major problem here. Big guys like Samsung and Google can throw their weight around and squeeze a year or two of extra support out. But for small players like fairphone it's not surprising that they find themselves in this position.

The fact is that any sane company would prefer to make money selling new chips, rather than spending it to support old ones. This problem will persist until consumers start demanding longer software support on their devices and making it a major part of their buying decision.

JacobCoffinWrites ,
@JacobCoffinWrites@slrpnk.net avatar

I've posted about this elsewhere on this instance, but LineageOS has made a good start on supporting Android phones beyond their official support

anothercatgirl , in A green roof or rooftop solar? You can combine them in a biosolar roof — boosting both biodiversity and power output

At that point you might as well just place an entire agrivoltaic system on your roof, although it requires significant structural support and you would be living underground.

DarkThoughts ,

Agriculture is terrible for biodiversity and so are cities. This is one way of supporting more biodiversity in areas where it is already struggling.

anarchotoothbrushist , in Use for excess clean energy at home

I'm no expert, but I'd imagine figuring out a (safe) way to use it with your water heater would be the low-hanging fruit, in terms of least-complexity for the amount of grid consumption you'd potentially save.

evasive_chimpanzee OP ,

That's an interesting idea. A water heater is a really underutilized battery that most households have. I suppose you could hook it up to a thermostat with a set point a couple degrees higher than the mains (or gas) powered thermostat.

A quick search says in my location with a 100W panel, I'll generate 400Wh as my daily average (1.44 MJ). With a 150 L tank, that gives you about 2.25 K increase in temp for a day.

That's not nothing.

ptz , (edited ) in Use for excess clean energy at home
@ptz@dubvee.org avatar

I had a spare 50W panel and charge controller that I used similarly for camping. Had more or less the same thought as you: I should use this year round.

Ended up building a wooden box with a couple of old car batteries inside along with the controller. Kept it outside and ran a cable inside carrying 12v (make sure you put an inline fuse after the battery in case it short circuits along the way). Used the 12v from that and some old car chargers to set up a charging station for all my devices.

The car chargers were all random plug styles since they were from a box of stuff I've accumulated over the years, so I cut those off and spliced on USB-A female ports so they could charge any USB device. I eventually ran a second pair of 12v wires so I could run a small 100w inverter from the batteries.

Worked great, but the car batteries crapped out after about 3 years (in all fairness, they were junk to start with).

If I had to do it over again, I'd do it similarly but use 12v USB-C power-delivery adapters instead so I could charge bigger stuff like my laptop without having to use an inverter.

lettruthout ,

Awesome effort! If not done already, you may want to look into venting that outside box. I believe there are examples of the out gassing of enclosed lead-acid batteries causing corrosion of nearby metals. Hilarity ensued.

ptz ,
@ptz@dubvee.org avatar

It doesn't exist anymore, but yeah, good call. I never replaced it once the batteries finally gave out, and I moved less than a year later.

It did have vents on the sides for airflow, but that was more of a consideration for heat build up and keeping the controller from cooking in the summer. It was also less a "box" and more like a small doghouse (including shingles lol). I atually gave it to a neighbor after I was done with it; they cut a hole in the door and used it as a cat house.

evasive_chimpanzee OP ,

3 years seems pretty good for using a car battery outside of it's preferred use case. I guess that depends on how good/bad you were about deep cycling it.

Currently, the batteries I'm using are my power tool batteries, which are 18V so they charge through a dedicated (12V) charger, and I have a little USB A/C and low powered inverter that uses them. I probably wouldn't necessarily want to put my lithium batteries through every day cycling, though.

I've thought about generating hydrogen with it to use for experiments and such, but idk if I have the space for that.

ptz , (edited )
@ptz@dubvee.org avatar

3 years seems pretty good for using a car battery outside of it's preferred use case.

Better than that :) They were junk car batteries when I got them, and I still got 3 years out of them. But yeah, they didn't get deep cycled much or at all since there were 2 in parallel and the loads I had on them were very small (5-6 500 mAh cell phone chargers and occasionally some LED rope lights).

When I eventually hooked an inverter up to charge my laptop or run a lamp during power outages, they started to show their age with the extra current draw. I think that's what finally did them in.

Yeah, lithium batteries wouldn't like that kind of daily cycle without some kind of charge/discharge limiter to keep them in the 30-70% range. That's basically what hybrid and EV battery managers do to prolong their useful lifespan. I think LiFePO4 lithium batteries would tolerate that better (they're the ones typically used in e-bikes), but they're not cheap. I've also found it difficult / expensive to find solar chargers for them (to be fair, mine is 48v 20AH so finding any aftermarket charger for it has been a challenge lol).

solo , in New recycling method makes solar cells even more environmentally friendly

the number of cells ready for recycling will grow dramatically within a few decades, and there are expected to be 80 million tonnes of panels ready for recycling each year by 2050.

That sounds like it's a lot

The new work, rather than focusing on completely dissolving the materials used in constructing the panel, relies on a brief chemical treatment that largely severs the connections among the individual layers. While this results in some chemical byproducts, most of the material ends up intact and in a relatively pure form.

That sounds impressive. Hope the chemical byproducts are environmentally friendly or something.

Cybermatrix1 , in Sand Batteries vs Water Batteries
@Cybermatrix1@slrpnk.net avatar

It is an interesting these technologies you compare. Yes, a sand battery is in potential capable of storing higher temperatures if the source can generate these temperatures. We also have to look at the heat transfer that will seperate both energy buffers if seen from an application point of view. The heat transfer in sand is very low and this intrinsic insulation of sand begins to be very interesting when larger volumes are used. Water has a problem that it needs an extra insulation layer and larger volumes would be less interesting in comparison. However water is faster in exchange and is interesting as smaller buffer with shorter bursts and intake of heat.

proctonaut ,

Alright so I have a question for you. Let's say I'm designing one of these things for a greenhouse or something. I'm thinking underground storage tank of 500 gallons or so but basically filling it with sand and then again topping it off with water. It should minimize convection currents in the water and where it there isn't much of a thermal draw there shouldn't be much of an issue right?

Cybermatrix1 ,
@Cybermatrix1@slrpnk.net avatar

Unfortunately that would negate the high storage temperature of sand (up to 800 degree c) as water will turn into steam after 100deg. So it is either low temperature sand or water with lower energy density.

proctonaut ,

Thermal mass would be secondary for the sand. I'm more concerned with it helping the structure of the tank underground and avoiding slump from what the tank would be buried in. Probably feeding it heat from a thermal solar set-up.

DadBear OP ,

Good question, not being an expert I don't have a great answer. But maybe doing a composite sand that combined something like copper, iron, it aluminum dust with the sand to increase the ability of the battery to more easily move heat around. Or using the chosen metal in a bar or pipe as heat transfer out of the center. The only issue with that is it lowers the operating temp and would require more active cooling, this negating some of the self-insulating benefits of sand. This could be solved by treating them like control rods, and make them movable so they could be drawn out when extracting energy is not necessary.

Cybermatrix1 ,
@Cybermatrix1@slrpnk.net avatar

I like aluminium powder idea. And use the metal bar as heatpipe is a good idea. I would not see temperature as problem as most materials you mention can handle 800 deg. The idea is that you can draw energy from it thus cooling it. I think a molten salt chamber uses this combination of fast transfer and high temperature

DadBear OP ,

You're right about rapid transfer out. I guess I wasn't clear about the imagined scenario where the battery may sit untapped for hours or more, and that could definitely cause issues with the metal melting at the upper end of operator temps. Interesting idea for solarpunk story conflict: for whatever reason heat isn't being extracted fast enough so the batteries are overheating and 'slagging' themselves.

lemmyng , in Sand Batteries vs Water Batteries
@lemmyng@lemmy.ca avatar

What about loss of material due to evaporation? Sand batteries can retain their mass in an unsealed container, vs water batteries which would lose mass in an open container or be under dangerously high pressures in a sealed container.

FiniteBanjo ,

Assume closed system. The theory here is that when under pressure it becomes more difficult for some materials like water to change state, making it a viable energy storage medium.

perestroika , in Sand Batteries vs Water Batteries

I have superficially researched both options (with the conclusion that I cannot use either, since my installation would be too small, and would suffer from severe heat loss due to an unfavourable volume-to-surface ratio - it makes sense to design thermal stores for a city or neighbourhood, not a household).

I'd add a few notes:

  1. A thermal store using silicate sand is not limited by the melting point of the sand, but the structural strength of the materials holding the sand. You can count on stainless steel up to approximately 600 C, more if you design with reserve strength and good understanding of thermal expansion/contraction. Definitely don't count on anything above 1000 C or forget the word "cheap". I have read about some folks designing a super-hot thermal store, but they plan to heat graphite (self-supporting solid material) in an inert gas environment.

  2. Heat loss intensifies with higher temperatures, and the primary type of heat loss becomes radiative loss. Basically, stuff starts glowing. For example, the thermal conductivity of stone wool can be 0.04 W / mK at 10 C, and 0.18 W / mK at 600 C.

  3. Water can be kept liquid beyond 100 C. The most recent thermal stores in Finland are about 100 meters below surface, where the pressure of the liquid column allows heating water to 140 C.

  4. However, any plan of co-generation (making some electricity while extracting the stored heat) requires solid materials and high temperatures.

DadBear OP ,

Thanks for the input! I've had several more thoughts:

  1. You're absolutely right about the cost, but it could be contained with refractory cement and would not have to rely solely on metal casings. It seems like buying either in bulk has comparable pricing.

  2. interest problem. I tried to find some info, but there's a lot of engineeting math (I'm an English teacher who also loves the sciences) I don't have the time to sort out right now. I think that using rock wool and refractory cement (see number 1) could help offset this energy loss.

  3. I knew that water could be kept liquid under pressure, but for the purposes of citizen science and making tech more democratic, high pressure systems are a lot of risk and can be devastating when mistakes are made.

  4. Absolutely. And that's the goal of my thoughts. Finding a cheap material that can hold high temperatures and remain solid. The transfer to electricity could be done by using the heated mass to heat a hot pumped liquid or using transfer rods made of a solid material with a high heat transfer coefficient.

perestroika ,

The transfer to electricity could be done by using the heated mass to heat a hot pumped liquid or using transfer rods made of a solid material with a high heat transfer coefficient.

Alternatively, heat can be extracted by pumping liquid metal (sodium, tin, low-temperature eutectic alloys) in a pipework of copper (if there is chemical compatibility with copper). But handling liquid metal with a magnetic pump isn't typically done on the DIY tech level.

To be honest, I tried a fair number of experiments on the subject, including low-temperature Stirling motors. They're difficult to build well. I would recommend plain old steam turbine. Steam means pressure, pressure means precautions (risk of bursting, risk of getting burned), but modern approaches to boilers try to minimize the amount of water in the system, so it couldn't flash to steam and explode.

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