perestroika

joined 1 year ago
[–] [email protected] 0 points 4 days ago

P.S. I have once used DC to power a pump "directly". I use quotation marks because the pump (a water pump) was a brushless DC motor with an integrated controller. I used it on a field for removing water after a spring flood. Its controller accepted 24..48 V input, and it was powered from a 40 V solar panel brought on a wheelbarrow. :)

[–] [email protected] 0 points 4 days ago* (last edited 4 days ago) (1 children)

instead of powering the heat pump from the wall, the heat pump can be connected directly to a PV

I have no experience with this exact combination. I know that "batteryless" inverters exist, but most of them are on-grid inverters. In that scenario, all that matters is monitoring your production: if you don't want grid energy, you only run your system when your PV produces enough.

Another type of batteryless inverters are "pump inverters". Farmers seem to like them for pumping water from wells into water towers. A pump inverter can be configured to run at 50 Hz (or 60 Hz for North Americans) and 230..240 V (or 110 V for North Americans) alright, but it is not designed to power electronic devices, but dumb agricultural motors. There is considerable risk involved with powering a heat pump from a pump inverter, unless you find an exceptionally simple and dumb heat pump with very limited or resilient steering electronics.

Efficiency losses are small anyway, but mostly happen during battery storage or when voltage needs to rise or drop considerably (e.g. a transition of 700 -> 24 V or 24 -> 240 V would cause a small efficiency loss).

I’ve heard that a PV can directly power a compressor

This seems unlikely as the compressor would have to be a brushed DC motor. That kind of motors don't last long, they wear out their brushes. Long-lasting motors are brushless, and those generally cannot be run on DC power. For example, a "brushless DC" motor is essentially a three-phased AC motor, just its controller (full of smartness and MOSFET transistors) accepts DC input.

If you have a good technical overview of your heat pump system, maybe you can locate a point where regulated DC can be fed into the system, but that would be hacking. Alternatively, maybe a niche market already exists for DC-powered heat pumps, e.g. for caravans, trucks or ships? But on niche markets, prices typically aren't good for you. :(

[–] [email protected] 0 points 2 weeks ago (1 children)

Relays: my use for truck relays is switching on heaters in my thermal storage water tank. Not big ones, though - I use relays rated for 24V and 40A of current. Since they are old, I have applied a safety margin and only let 25 A flow through them, so each of them handles 24 x 25 = 600 W.

As for using DC appliances: benefits do exist. If a household has a low voltage DC battery bank (some do, some don't) then dropping the battery voltage a few times to power car parts comes with a smaller efficiency loss. In my household, DC appliances are used for lighting, communications, computing, cooling food, pumping water and soldering electronics. The rest goes via AC. I think a car air conditioner could cool some small storage room decently. With big living rooms, it would have difficulty since it's a small device.

[–] [email protected] 0 points 2 weeks ago* (last edited 2 weeks ago)

it would (as far as i understand with high school chemistry) be strictly more efficient to electrolyse rust directly

I'm not a chemist either, but I do know a bit of chemistry.

Typically, you need a solution of NaOH (sodium hydroxide) to directly reduce iron oxide in an electrolysis cell. If your iron oxide contains impurities, those may react with NaOH and ruin the fun. Also, if you have exposure to CO2, your NaOH will gradually degrade, producing NaHCO3 and losing potency.

My impression: wet electrolysis is great for making high purity iron, but it would be hard to make it work for energy storage.

[–] [email protected] 0 points 2 weeks ago* (last edited 2 weeks ago) (5 children)

Relays can be used for anything, and a car contains a fair number.

You can make a pulse jet engine from a muffler parts, but a solarpunk society would probably not do that. :)

Copper brake pipe and cooling radiators can be used as heat exchangers for other stuff.

Air conditioner parts can be reverse-used for Stirling engines or to pump heat in other contexts.

 

This is not just a "happy birthday" post for Linux, but also a reminder that despite it becoming big and professional, the freedom to tinker with Linux remains accessible.

I had to use this freedom recently when I discovered that V4L video pipelines could buffer up to 32 frames both on the encoder and decoder (unacceptable, we demand minimum latency!) so it was again time to recompile the kernel. :)

My previous time to recompile parts of Linux had been a week ago. Some hacker had discovered a way of tricking their WiFi card beyond the legally permitted power - with what I understand as thermal compensation settings. Wanting to taste the sweet extra milliwatts, I noticed that nobody was packaging that driver as a binary, so the only way to get it was to patch and recompile its kernel module.

Finally of course, thanks to Linux we have countless open-source drivers and if you want to venture onto the path that Linus Torvalds took - of building an operating system - congratulations, you have less obstacles in your way. :) Some people have taken this path with the Circle project and you can compile your homebrew and bare-metal kernel for a Raspberry Pi with reasonable effort, and it can even draw on the screen, write to serial ports and flip GPIO lines without reverse-engineering anyone's trade secrets. :)

[–] [email protected] 0 points 1 month ago* (last edited 1 month ago) (2 children)

Yep, indeed, I'm already discovering differences too. :) A good document for techies to read seems to be here.

https://reticulum.network/manual/understanding.html

I also think I see a problem on the horizon: announce traffic volume. According to this description, it seems that Reticulum tries to forward all announces to every transport node (router). In a small network, that's OK. In a big network, this can become a challenge (disclaimer: I've participated in building I2P, but ages ago, but I still remember some stuff well enough to predict where a problem might pop up). Maintenance of the routing table / network database / is among the biggest challenges when things get intercontinental.

[–] [email protected] 0 points 1 month ago* (last edited 1 month ago) (4 children)

Interesting project, thank you for introducing. :)

I haven't tested anything, but only checked their specs (sadly I didn't find out how they manage without a distributed hashtable).

Reticulum does not use source addresses. No packets transmitted include information about the address, place, machine or person they originated from.

Sounds like mix networks like I2P and (to a lesser degree, since its role is proxying out to the Internet) like TOR. Mix networks send traffic using the Internet, so the bottom protocol layers (TCP and UDP) use IP addresses. End to end messages use cryptographic identifiers.

There is no central control over the address space in Reticulum. Anyone can allocate as many addresses as they need, when they need them.

Sounds like TOR and I2P, but people's convenience (easily resolving a name to an address) has created centralized resources on these nets, and will likely create similar resources on any network. An important matter is whether the central name resolver can retroactively revoke a name (in I2P for example, a name that has been already distributed is irrevocable, but you can refuse to distribute it to new nodes).

Reticulum ensures end-to-end connectivity. Newly generated addresses become globally reachable in a matter of seconds to a few minutes.

The same as aforementioned mix networks, but neither of them claims operability at 5 bits per second. Generally, a megabit connection is advised to meaninfully run a mix network, because you're not expected to freeload, but help mix traffic for others (this is how the anonymity arises).

Addresses are self-sovereign and portable. Once an address has been created, it can be moved physically to another place in the network, and continue to be reachable.

True for TOR and I2P. The address is a public key. You can move the machine with the private key anywhere, it will build a tunnel to accept incoming traffic at some other node.

All communication is secured with strong, modern encryption by default.

As it should.

All encryption keys are ephemeral, and communication offers forward secrecy by default.

In mix networks, the keys used as endpoint addresses are not ephemeral, but permanent. I'm not sure if I should take this statement at face value. If Alice wants to speak to Bob tomorrow, some identifier of Bob must not be ephemeral.

It is not possible to establish unencrypted links in Reticulum networks.

Same for mix networks.

It is not possible to send unencrypted packets to any destinations in the network.

Same.

Destinations receiving unencrypted packets will drop them as invalid.

Same.

[–] [email protected] 0 points 1 month ago* (last edited 1 month ago)

Well, today they are actually in production, while 5 years ago they were in laboratories.

[–] [email protected] 4 points 1 month ago* (last edited 1 month ago)

As an anarchist who would welcome other anarchists - sadly, I doubt if that's a reliable recipe to stop climate change.

Limiting (hopefully stopping) climate change can be done under almost any political system... except perhaps dictatorial petro-states. However, it takes years of work to tranform the economy. Transport, heating, food production - many things must change. Perhaps the simplest individual choices are:

  • going vegetarian (vegan if one knows enough to do the trick)
  • avoidance of using fossil fueled personal vehicles
  • improving home energy efficiency (especially in terms of heating)
  • avoidance of air travel
  • avoidance of heavy goods delivered from distant lands

The rest - creating infrastructure to produce energy cleanly and store sufficient quantities - are typically societal choices.

As for corals - I would start by preserving their biodiversity, sampling the genes of all coral and coral-related species and growing many of them in human-made habitats. If we're about to cause their extinction, it's our obligation to provide them life support until the environment has been fixed.

Also, I would consider genetically engineering corals to tolerate higher temperatures. Since I understand that this is their critical weakness, providing a solution could save ecosystems. If a solution is feasible, that is.

Corals reproduce sexually so a useful gene obtained from who knows where would spread among them (but slowly - because typical colonies grow bigger asexually). Also, I would keep in mind that this could have side effects.

As for tempeature - it will be rising for some time before things can be stopped. Short of geoengineering, nothing to be done but reduce emissions, adapt, and help others adapt. The predictable outcome - it will get worse for a long while before it starts getting any better.

[–] [email protected] 17 points 2 months ago* (last edited 2 months ago)

News of the sentencing reached the public broadcaster here in Estonia, including Dale Vince's comment that "this resembles Russia or maybe North Korea" and Chris Packham's assessment that "this is a threat against freedom of speech".

I hope the judgement gets overturned on appeal, and the law that enabled the judgement gets scrapped or rewritten.

I also suspect that the next people who want to stop traffic will not choose peaceful assembly as their method, but will use far more dangerous methods - sabotage from distance, e.g. no more traffic lights on a big intersection. Needless to say, state will cry "terrorism" then, and that is not a desirable outcome, so I hope nobody feels compelled to prove the point.

[–] [email protected] 0 points 2 months ago* (last edited 2 months ago) (1 children)

The article is mostly correct. :)

Notes: out of the three, Latvia has serious energy storage - a 4 billion cubic meter (at normal pressure) underground gas store, sufficient to carry all three countries over the winter. So far, it's filled with fossil natural gas - but some day it could be filled with synthesized methane.

As a backup option, Estonia has oil shale - probably the worst fuel on Earth, so the price of emitting CO2 keeps those plants out of the energy market during summer. During winter, they come online though.

As for solar, we aren't planning to rely much on that. Solar capacity has of course skyrocketed, but only because it's very easy to install. For me, it provices a nice way to charge my car from April to October. But at latitudes 55 to 60, days are really very short in midwinter, so wind and waste wood are the likely candidates in future - after oil shale leaves the scene, but before synthetic gas becomes feasible.

Regarding pumped hydro - it can stabilize a day, but can't stabilize a week or month. Lithuania has a biggish (~10 GWh) pumped storage facility. The rest of Baltics don't have suitable terrain. Estonia has limestone banks, but they're under various forms of protection and even if one built a lot of pumped hydro, the low elevation difference (up to 50 meters) means one couldn't support the electric grid through more than a few days.

Regarding hydrogen - maybe. But hydrogen is difficult to store, so I'm betting on wind, and on sourcing technology from Germany to produce synthetic methane from excess power during summer, and pumping it to Latvia for storage.

Finally - connecting to the continental EU power grid allows importing energy when local wind isn't strong enough, and exporting any surplus. So far, all three countries are still in the ex-Soviet synchronization area (common with Russia and Belarus, but with no trade, just synchronization), and thus unable to connect with the EU synchronization area. Local power companies have been building synchronous compensators (devices that steer grid frequency) for the past 2 years to drop this dependency.

If things go as planned, Baltic countries will sever those connections and join the EU grid via Poland in winter 2025. Undersea cables already go from Estonia to Finland and Lithuania to Sweden, but in the current political conditions, I don't think anyone counts of them for sure (a Chinese-owned but Russian-crewed ship broke the Estonia-Finland gas pipeline last autumn when dragging its anchor during a storm - it's still unsure if the damage was accidental or not).

[–] [email protected] 1 points 3 months ago (1 children)

The Ugandan military playing security guards for a China-controlled oil project... I think explaining human rights over there will have to start from zero - and may have to be backed with "or else" statements - if there exists an institution in a suitable position to issue them. :o

 

Long story made short: apparently, the previous administration didn't really try (since it was Bolsonaro's, I am not surprised). EU import controls and financial interventions have also helped:

He believes the slowdown is due to a combination of factors: the resumption of embargoes and other protection activities by the government, improved technical analysis that reveal where problems are occurring more quickly and in more detail, greater involvement by banks to deny credit to landowners involved in clearing trees, and also wariness among farmers generated by the European Union’s new laws on deforestation-free trade. It may be no coincidence that deforestation has not fallen as impressively in the cerrado savanna, which is not yet covered by the EU’s controls.

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