5 ms·

Nuclear batteries removing the need for electrical wiring seems very pie in the sky to me but perhaps I'm just ignorant of the practical application of it. Con

Nuclear batteries removing the need for electrical wiring seems very pie in the sky to me but perhaps I'm just ignorant of the practical application of it. Concrete seems far more common in residential construction outside of the U.S. I wonder if technologies such as aircrete (concrete with uniform foam produced air bubbles). Also well There's Your Problem had an interesting article about the 5-1 construction that is used for a lot of new apartment buildings in the U.S. https://wtyppod.podbean.com/e/episode-46-five-over-ones/ https://wtyppod.podbean.com/e/episode-46-five-over-ones/

vbezhenar 5y ago
Aerated concrete is extremely popular in Kazakhstan and Russia in private houses. It's cheaper than bricks, it's sturdy enough, it provides good insulation, it does not require much skill to use, pieces are huge, so it's much faster to build. There are drawbacks, of course, but overall it's a very popular technology.
- bolangi 5y ago
  I know a guy who researched aerated concrete. He used a slimy additive to help hold the bubbles. Basically, the compression strength of concrete is so much higher than necessary that addition of a large portion of air results in a material that is much lighter with more than adequate compression strength. He couldn't find interest among concrete companies in his state.
- elihu 5y ago
  I think in the U.S. the only place that makes the stuff (Aercon) is in Florida, and there's Hebel that has a plant in Mexico near Texas.
- jessaustin 5y ago
  ...it provides good insulation... This might be true, but it would be surprising, since even "aerated" concrete would still be made of highly thermally conductive... concrete.
  - R0b0t1 5y ago
    The thermal mass of your house is part of the perceived insulation. In the desert especially nights are cold, the house chills, and retains that chill throughout the day, keeping it cool inside.
    - earleybird 5y ago
      Thermal mass to manage comfort could be seen as tuning latency for your arrival and departure of your heat packets.
  - elihu 5y ago
    If memory serves, normal concrete has an R value of about 1 per foot, whereas AAC is more like 1 to 2 per inch. So, an 8 inch wall would have an R-value of about 8-16. That doesn't seem like enough for a cold climate, so I'd assume for those applications you'd probably add an extra layer of actual insulation. (This would mean having pretty thick walls.) You wouldn't need as much supplemental insulation as you would with a regular concrete wall, though. The thermal mass is also nice, though it doesn't really help much in winter-time. I think AAC is a bit more suited to warm desert climates where you have a daily hot/cold cycle.
    - vbezhenar 5y ago
      20-inch wall is enough for pretty cold climate according to my calculations. Either that or thin wall with insulation (or thin wall and more money on heating which might be an acceptable solution, if you have cheap coal and your country does not care what you build).
    - PaulDavisThe1st 5y ago
      Fairly sure that AAC has less thermal mass than regular concrete. It's more air, less concrete, and the thermal mass comes from the concrete.
      - elihu 5y ago
        Yeah, that sounds right. Still, a lot less than concrete can still be a lot. And I think in most cases I'd rather have better insulation than more thermal mass.
- fpoling 5y ago
  In has been popular in the whole former USSR. But for some reason in past it was not considered as a suitable material for houses, only for storage facilities etc. But it could be just a cultural perception. For example, my father built a temporary house from it in Belarus in 1980s while waiting for the main house construction that was using ordinary bricks. I remember as a child that building from aerated concrete was indeed very quick affair.
  - ArkanExplorer 5y ago
    Disadvantages From Wikipedia: "Installation during rainy weather: AAC is known to crack after installation, which can be avoided by reducing the strength of the mortar and ensuring the blocks are dry during and after installation. Brittle nature: they need to be handled more carefully than clay bricks to avoid breakage. Attachments: the brittle nature of the blocks requires longer, thinner screws when fitting cabinets and wall hangings and wood-suitable drill bits or hammering in. Special, large diameter wall plugs (anchors) are available at a higher cost than common wall plugs. Insulation requirements in newer building codes of northern European countries would require very thick walls when using AAC alone. Thus many builders choose to use traditional building methods installing an extra layer of insulation around the entire building." https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete
- kingsuper20 5y ago
  >Aerated concrete is extremely popular in Kazakhstan and Russia in private houses. In California (FWIW), I expect that you hit seismic issues.
  - Gibbon1 5y ago
    Problem in California is insane mandated R values for walls. Aerated concrete can meet previous standards. But not the new ones. So it's use is effectively banned. Old saw about Generals fighting the last war. Energy efficiency standards assume the need to conserve limited supplies for fossil fuels. And the need to not interfere with building large houses for upper middle class people. Bad thing is R value is a metric designed to upsell insulation. R30 insulation is twice as good as R15, if you're the guy selling it. If you're the guy buying it, not as much.
    - falcolas 5y ago
      Considering that you can put foam on the inside and outside of walls (exceptionally common in high-efficiency homes), this is likely not the issue.
      - Gibbon1 5y ago
        I run my furnace for 5 months out of the year. Total yearly cost for nat gas is about $600. And my house is a really drafty 1950's era one. So the max that insulation could save me is $600, that's it. A heat pump and solar installation needed heat my house in the winter would cost about $12000. But actually the heat pump would only run as I mentioned above for 5 months out of the year. So really just to offset the energy, $6000. Economically high performance insulation systems lose to solar panels. That wasn't true 10 years ago. But it's true now. And it'll get worse going forward.
        falcolas 5y ago
        When you're building a house, it's not hard to add additional insulation on either side of the framing. Not terribly expensive, either. You also save on the installation of the furnace (and AC) because it just requires very little heating and cooling. Since insulation is low maintenance, you'll get those savings over the whole lifespan of the house. Now, if you're in an existing house, it likely doesn't make sense to tear down all your siding and drywall just to add insulation, since you're having to both demo and build.
- falcolas 5y ago
  Can you pre-tension aerated concrete? Concrete is already poor in tensile strength, it feels like creating voids in it would only make that worse. And tensile strength is largely required for larger, earthquake safe concrete fixtures.
  - vbezhenar 5y ago
    AFAIK for earthquake-safe buildings you're supposed to build a frame from an ordinary reinforced concrete and then fill walls with blocks from aerated concrete. Not sure about details, I'm not living in earthquake-dangerous area, so never had to research more about it.
elihu 5y ago
I think that was kind of a whimsical suggestion; like, even if you had a magical technology that eliminated all need for electrical wiring, you'd still only reduce building costs by a small amount.
- Gibbon1 5y ago
  I've thought that creating a 100-150 watt power over Ethernet standard for home wiring would be a win. Advantage faster install, cheaper cabling, and better safety. Better safety because you can limit the default power to under 15W. Faster install because you use crimp connectors.
  - imgabe 5y ago
    What if you want to plug in a vacuum cleaner, hair dryer, space heater, curling iron, or any other thing that might use more than 150 watts?
    - Gibbon1 5y ago
      > vacuum cleaner Battery powered. > hair dryer, curling iron. Bath room. > space heater Just no.
      - imgabe 5y ago
        Desktop computer? Large TV + stereo system? Refrigerator? Toaster oven? Printer? There’s a lot of things that use more than 150w. I can’t imagine how you’re going to sell people on “here let’s make your house fundamentally worse and less capable. Oh, and you also need to buy all new appliances with different plugs“
      - tapland 5y ago
        So you created a system for providing lamps with electricity. Why not battery power those low power items as well?
R0b0t1 5y ago
> Nuclear batteries removing the need for electrical wiring seems very pie in the sky to me but perhaps I'm just ignorant of the practical application of it. tl;dr very feasible sans NIMBYs The DoE investigated this exact thing. I happened across the papers while browsing microfiche. It makes the most sense to serve a neighborhood off small house/shed sized generating facility. As you scale up you can switch to normal turbine operation, as you scale down you move back to thermoelectric operation. Single houses could be powered from thermoelectric piles but this would probably have been reserved for expensive, remote vacation homes. Closer to battery sized, you can layer radioactive material against quantum dots that turn alpha particles into photons and emit those photons directly onto a PV cell.
- falcolas 5y ago
  What’s the estimated kWH for one of those “nuclear batteries”?
  - R0b0t1 5y ago
    Abysmal. A current design you can see is the tritium nuclear battery. I misspoke, it is beta particles that generate the photons. The reaction produces nanowatts. If you remake this system with quantum dots and layered materials it is actually useful and can power small electronics, like a bug. But it needs light shielding.
tootie 5y ago
I thought the point about modular wiring was interesting. Why aren't all wall studs fitted with grommeted mouseholes at outlet and switch height?
- 015UUZn8aEvW 5y ago
  You only need holes in certain places and they can be drilled in seconds. Electricians use specialized right angle drills called "hole hawgs" to drill them.
- mikebelanger 5y ago
  Most wall studs don't have an outlet or a switch attached. Besides, wires come in from all heights, making the height for the hole of the wiring highly variable. Also people's preferences for switches and outlets varies (albeit probably not much).
  - falcolas 5y ago
    Not to mention requiring a certain distance between wires for high (plugs, lights, etc) and low voltage (i.e. ethernet) applications.
- falcolas 5y ago
  Some are. Especially engineered studs (like those which are closer to beams and filled with insulation) and joists. But holes are fairly quick to add to wood.
- prawn 5y ago
  Made me wonder about 'service walls' which would be a pre-built piece that was incorporated into a regular build, but had wires/pipes/etc already built in. You could have a "spine" of a house setup like this, or like a hub, but that doesn't help power points or piping on other walls of a room. So much of the hassle and cost is that we are building almost a unique house each time and everyone has their own idea of what they want in a house, or uses that unique aspect to express themselves.
ben_w 5y ago
Nuclear batteries have their place, but consumer products are not it. First, you can’t switch them off, so they are either always warm or the are trickle-charging another storage system (batteries, capacitors, whatever) within the device. Second, the radiation. You can do various things to limit the risk, but the LD50 is something like 0.25 watts of absorbed ionising radiation sustained for 18 minutes, so damage to the batteries (malicious or accidental) would have significantly greater harms than, say, asbestos, CFCs, or domestic carbon monoxide sources. You absolutely do not want a 10 watt lightbulb powered by built-in atomic batteries anywhere it can get messed with, let alone a 2 kW kettle or a 5 kW oven. https://en.wikipedia.org/wiki/Acute_radiation_syndrome https://en.wikipedia.org/wiki/Acute_radiation_syndrome

vbezhenar 5y ago

Aerated concrete is extremely popular in Kazakhstan and Russia in private houses. It's cheaper than bricks, it's sturdy enough, it provides good insulation, it does not require much skill to use, pieces are huge, so it's much faster to build. There are drawbacks, of course, but overall it's a very popular technology.

bolangi 5y ago
I know a guy who researched aerated concrete. He used a slimy additive to help hold the bubbles. Basically, the compression strength of concrete is so much higher than necessary that addition of a large portion of air results in a material that is much lighter with more than adequate compression strength. He couldn't find interest among concrete companies in his state.
elihu 5y ago
I think in the U.S. the only place that makes the stuff (Aercon) is in Florida, and there's Hebel that has a plant in Mexico near Texas.
jessaustin 5y ago
...it provides good insulation... This might be true, but it would be surprising, since even "aerated" concrete would still be made of highly thermally conductive... concrete.
- R0b0t1 5y ago
  The thermal mass of your house is part of the perceived insulation. In the desert especially nights are cold, the house chills, and retains that chill throughout the day, keeping it cool inside.
  - earleybird 5y ago
    Thermal mass to manage comfort could be seen as tuning latency for your arrival and departure of your heat packets.
- elihu 5y ago
  If memory serves, normal concrete has an R value of about 1 per foot, whereas AAC is more like 1 to 2 per inch. So, an 8 inch wall would have an R-value of about 8-16. That doesn't seem like enough for a cold climate, so I'd assume for those applications you'd probably add an extra layer of actual insulation. (This would mean having pretty thick walls.) You wouldn't need as much supplemental insulation as you would with a regular concrete wall, though. The thermal mass is also nice, though it doesn't really help much in winter-time. I think AAC is a bit more suited to warm desert climates where you have a daily hot/cold cycle.
  - vbezhenar 5y ago
    20-inch wall is enough for pretty cold climate according to my calculations. Either that or thin wall with insulation (or thin wall and more money on heating which might be an acceptable solution, if you have cheap coal and your country does not care what you build).
  - PaulDavisThe1st 5y ago
    Fairly sure that AAC has less thermal mass than regular concrete. It's more air, less concrete, and the thermal mass comes from the concrete.
    - elihu 5y ago
      Yeah, that sounds right. Still, a lot less than concrete can still be a lot. And I think in most cases I'd rather have better insulation than more thermal mass.
fpoling 5y ago
In has been popular in the whole former USSR. But for some reason in past it was not considered as a suitable material for houses, only for storage facilities etc. But it could be just a cultural perception. For example, my father built a temporary house from it in Belarus in 1980s while waiting for the main house construction that was using ordinary bricks. I remember as a child that building from aerated concrete was indeed very quick affair.
- ArkanExplorer 5y ago
  Disadvantages From Wikipedia: "Installation during rainy weather: AAC is known to crack after installation, which can be avoided by reducing the strength of the mortar and ensuring the blocks are dry during and after installation. Brittle nature: they need to be handled more carefully than clay bricks to avoid breakage. Attachments: the brittle nature of the blocks requires longer, thinner screws when fitting cabinets and wall hangings and wood-suitable drill bits or hammering in. Special, large diameter wall plugs (anchors) are available at a higher cost than common wall plugs. Insulation requirements in newer building codes of northern European countries would require very thick walls when using AAC alone. Thus many builders choose to use traditional building methods installing an extra layer of insulation around the entire building." https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete
kingsuper20 5y ago
>Aerated concrete is extremely popular in Kazakhstan and Russia in private houses. In California (FWIW), I expect that you hit seismic issues.
- Gibbon1 5y ago
  Problem in California is insane mandated R values for walls. Aerated concrete can meet previous standards. But not the new ones. So it's use is effectively banned. Old saw about Generals fighting the last war. Energy efficiency standards assume the need to conserve limited supplies for fossil fuels. And the need to not interfere with building large houses for upper middle class people. Bad thing is R value is a metric designed to upsell insulation. R30 insulation is twice as good as R15, if you're the guy selling it. If you're the guy buying it, not as much.
  - falcolas 5y ago
    Considering that you can put foam on the inside and outside of walls (exceptionally common in high-efficiency homes), this is likely not the issue.
    - Gibbon1 5y ago
      I run my furnace for 5 months out of the year. Total yearly cost for nat gas is about $600. And my house is a really drafty 1950's era one. So the max that insulation could save me is $600, that's it. A heat pump and solar installation needed heat my house in the winter would cost about $12000. But actually the heat pump would only run as I mentioned above for 5 months out of the year. So really just to offset the energy, $6000. Economically high performance insulation systems lose to solar panels. That wasn't true 10 years ago. But it's true now. And it'll get worse going forward.
      - falcolas 5y ago
        When you're building a house, it's not hard to add additional insulation on either side of the framing. Not terribly expensive, either. You also save on the installation of the furnace (and AC) because it just requires very little heating and cooling. Since insulation is low maintenance, you'll get those savings over the whole lifespan of the house. Now, if you're in an existing house, it likely doesn't make sense to tear down all your siding and drywall just to add insulation, since you're having to both demo and build.
falcolas 5y ago
Can you pre-tension aerated concrete? Concrete is already poor in tensile strength, it feels like creating voids in it would only make that worse. And tensile strength is largely required for larger, earthquake safe concrete fixtures.
- vbezhenar 5y ago
  AFAIK for earthquake-safe buildings you're supposed to build a frame from an ordinary reinforced concrete and then fill walls with blocks from aerated concrete. Not sure about details, I'm not living in earthquake-dangerous area, so never had to research more about it.

elihu 5y ago

I think that was kind of a whimsical suggestion; like, even if you had a magical technology that eliminated all need for electrical wiring, you'd still only reduce building costs by a small amount.

Gibbon1 5y ago
I've thought that creating a 100-150 watt power over Ethernet standard for home wiring would be a win. Advantage faster install, cheaper cabling, and better safety. Better safety because you can limit the default power to under 15W. Faster install because you use crimp connectors.
- imgabe 5y ago
  What if you want to plug in a vacuum cleaner, hair dryer, space heater, curling iron, or any other thing that might use more than 150 watts?
  - Gibbon1 5y ago
    > vacuum cleaner Battery powered. > hair dryer, curling iron. Bath room. > space heater Just no.
    - imgabe 5y ago
      Desktop computer? Large TV + stereo system? Refrigerator? Toaster oven? Printer? There’s a lot of things that use more than 150w. I can’t imagine how you’re going to sell people on “here let’s make your house fundamentally worse and less capable. Oh, and you also need to buy all new appliances with different plugs“
    - tapland 5y ago
      So you created a system for providing lamps with electricity. Why not battery power those low power items as well?

R0b0t1 5y ago

> Nuclear batteries removing the need for electrical wiring seems very pie in the sky to me but perhaps I'm just ignorant of the practical application of it. tl;dr very feasible sans NIMBYs The DoE investigated this exact thing. I happened across the papers while browsing microfiche. It makes the most sense to serve a neighborhood off small house/shed sized generating facility. As you scale up you can switch to normal turbine operation, as you scale down you move back to thermoelectric operation. Single houses could be powered from thermoelectric piles but this would probably have been reserved for expensive, remote vacation homes. Closer to battery sized, you can layer radioactive material against quantum dots that turn alpha particles into photons and emit those photons directly onto a PV cell.

falcolas 5y ago
What’s the estimated kWH for one of those “nuclear batteries”?
- R0b0t1 5y ago
  Abysmal. A current design you can see is the tritium nuclear battery. I misspoke, it is beta particles that generate the photons. The reaction produces nanowatts. If you remake this system with quantum dots and layered materials it is actually useful and can power small electronics, like a bug. But it needs light shielding.

tootie 5y ago

I thought the point about modular wiring was interesting. Why aren't all wall studs fitted with grommeted mouseholes at outlet and switch height?

015UUZn8aEvW 5y ago
You only need holes in certain places and they can be drilled in seconds. Electricians use specialized right angle drills called "hole hawgs" to drill them.
mikebelanger 5y ago
Most wall studs don't have an outlet or a switch attached. Besides, wires come in from all heights, making the height for the hole of the wiring highly variable. Also people's preferences for switches and outlets varies (albeit probably not much).
- falcolas 5y ago
  Not to mention requiring a certain distance between wires for high (plugs, lights, etc) and low voltage (i.e. ethernet) applications.
falcolas 5y ago
Some are. Especially engineered studs (like those which are closer to beams and filled with insulation) and joists. But holes are fairly quick to add to wood.
prawn 5y ago
Made me wonder about 'service walls' which would be a pre-built piece that was incorporated into a regular build, but had wires/pipes/etc already built in. You could have a "spine" of a house setup like this, or like a hub, but that doesn't help power points or piping on other walls of a room. So much of the hassle and cost is that we are building almost a unique house each time and everyone has their own idea of what they want in a house, or uses that unique aspect to express themselves.

ben_w 5y ago

Nuclear batteries have their place, but consumer products are not it. First, you can’t switch them off, so they are either always warm or the are trickle-charging another storage system (batteries, capacitors, whatever) within the device. Second, the radiation. You can do various things to limit the risk, but the LD50 is something like 0.25 watts of absorbed ionising radiation sustained for 18 minutes, so damage to the batteries (malicious or accidental) would have significantly greater harms than, say, asbestos, CFCs, or domestic carbon monoxide sources. You absolutely do not want a 10 watt lightbulb powered by built-in atomic batteries anywhere it can get messed with, let alone a 2 kW kettle or a 5 kW oven. https://en.wikipedia.org/wiki/Acute_radiation_syndrome https://en.wikipedia.org/wiki/Acute_radiation_syndrome