perestroika

I think the study analyzed the footprint of the person, not the vehicle:

In this new study, the research team investigated whether consumers who purchase and drive such vehicles have a smaller carbon footprint than other consumers

The merits of electric vehicles are irrelevant to their study - and their study is irrelevant to the merits of electric vehicles.

So maybe they're not lying (or maybe they are, if they made a direct claim about the power mix of the Finnish grid), but they're definitely far from barking under the correct tree. They're barking in a different forest, not of transport economy, but of wealth and consumption. :)

The proliferation of a new technology typically doesn't start from poor people.

It starts from fanatics first. I built my first EV. It was crap, I cut it apart and sold the metal (environmental footprint: awful). Then I built my second EV. It drove around 10 000 km, but had to be retired due to metal fatigue (enviromental footprint: neutral at best, lesson learned: big).

I bought my third EV on a crashed vehicle auction. New front axle, stretching the frame back to correct dimensions... I drive it every day, but it's a crap car that I'd not recommend to my worst enemy. :) Environmental footprint: positive, I can produce fuel for myself from April to October. But if the same vehicle would be used by someone who doesn't produce (or buy) renewable power, the footprint would be less positive.

Anticipating the demise of my factory-made electric microcar, I am however building another EV. Again the footprint is negative, but I need information about how to easily manufacture one, and obtaining information has a cost in resources. :(

Meanwhile, of course, truly rich folks buy fancy and electronics-laden self-driving EVs which some then proceed to crash or mishandle due to lack of clue. People are like that and it will stick out in statistics.

IMHO: if they hadn't bought an EV, they'd have bought another kind of status symbol and would have used it even more wastefully. What matters more is what the average person can and will do. And how do we influence the auto makers to produce less resource-intensive vehicles?

I have a solar panel that died. A piece or plywood flung by a storm went right through it, leaving a 30 cm "wound".

Well, to be honest, it's alive, just weaker - the panel remains suitable for pumping water on the field during muddy season. I wouldn't take a good panel to such a bad place, but this panel, I have no worries about.

As for what happens when they really, really die - they get disassembled. The aluminum frame gets taken off and goes into metal recycling. Junction boxes go to where plastic goes - not a nice place. The glass and doped silicon go into a crushing mill, after which they get separated. The glass is easy to recycle, but the doped silicon is difficult to refine again to such a purity, so it likely won't become a solar panel. But it's a very small fraction of the panel's mass.

Looking at the beatiful show, I cannot avoid thinking: "each of them a potential weapon".

So in fair weather, when communication is smooth and all navigation systems are working, it's entirely feasible to coordinate a swarm of 10 000. Wow. :)

Soon enough, they will be coordinating each other in the presence of electronic warfare, and swarms of 100+ fly already, so 1000 is the next step. Anyone doing air defense is probably designing energy weapons (lasers, masers, etc) at a pace approaching madness, besides making ever-cheaper drones.

As for the environmental footprint - if each drone withstands 10 performances, they will probably save resources. :)

On individual scale, precisely that - a split type AC with one half indoors (or in a water tank) and the other half in an outdoor environement (air, water or ground).

If you're extracting heat from the environment, the machine lets the working fluid evaporate into the outdoor heat exchanger and compresses it back into the indoor heat exchanger. If you're cooling your premises - reverse that.

However, on a city scale, it's like "you've got a lot of sewage at 30 C" -> "your heat pump is a large building" -> "your sewage outflow is now at 10 C, but your underground heat reservoir gets charged to 140 C (stays liquid because of water column pressure), and you spend much less energy pumping the heat than you would spend heating the water directly".

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. :)

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. :(

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.

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.

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.

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.

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.