3 ms·

A few thoughts: - Someone needs to watch the stacking process. If there is a single error the whole tower can collaps and do a lot of damage. - You need a big

A few thoughts: - Someone needs to watch the stacking process. If there is a single error the whole tower can collaps and do a lot of damage. - You need a big (and expensive) foundation for a tower like this. - Is the low-cost-concrete a strong enough building material? - The generator needs cooling (in hydro pump it is cooled by the water flowing through)

ebikelaw 8y ago
Everybody seems fixated on the stacking, but it's clearly not central to the system, merely an artifact of the demonstration-scale (and presumably demonstration-budget) implementation. They could just as easily be lifting a tremendously massive object a small distance and then letting it back down again with fixed hoists, which eliminates all of the structural problems this stack of barrels faces. Also, that would allow a single unit to sink and source power continuously instead of intermittently like this crane.
- gitgud 8y ago
  Yes, you could have 1 massive block, but the stresses and risks on the system would be much higher. Probably not achievable with current common tower cranes. The beauty of this idea is that these tower cranes are standardised and ubiquitous. So it could be implemented immediately in almost any city in the world.
- foota 8y ago
  I think the engineering there is more difficult because you need very strong cabling and pulleys that can deal with huge load.
  - pas 8y ago
    Just use multiple attachment points. I think the problem with the one big weight is that it'd require an extra structure (a gantry) to hold it, whereas this is really simple logistically. Easy to transport and assemble.
adrianmonk 8y ago
It seems pretty easy to verify the blocks are stacked properly. First, make them out of a shape that naturally fits together. Then, build them with a vertical hole (shaft) through them. Put a reflector under the bottom one. Before the crane releases a block, it shines a light down the hole and checks if it is reflected back. Misalignment will block the light. (Or, you can do something similar with electricity, connected contacts on the top and bottom, and a check that current flows through the entire stack.)
- kardos 8y ago
  Sounds good except what do you do about biology that decides to take up residence in the holes?
  - adrianmonk 8y ago
    I suppose you'd have to clean it regularly. When the crane goes to pick up a block, it could do the optical continuity check then too. If it fails, that indicates that either the block was moved after it was stacked correctly (unlikely but possible) or it got dirty. In that case, something comes along and cleans it. Maybe a rod-shaped brush (like a vacuum beater) that spins. Or a water jet. Also, you can have more than one hole for redundancy. If one of them is clear, that should be good enough. Hmm, or rather than holes through the middle, make them notches or grooves on the side and shine a laser through them.
- progfix 8y ago
  That only works in theory. In practice the reflector, light, whatever gets dirty and you would have false alarms non-stop.
- saulrh 8y ago
  Slap a tiny solar-powered GPS unit and transmitter on each block. ~$10 of electronics is marginal compared to the $2000 of concrete for each block. If any break, you already have a crane that you can use to move the block out of the way for repair; just hand it over to an operator who can do the special-case operation by hand. If you get a beacon unit with a MTBF of 10 years and not awful clustering you might get one to five failing per stack per day, so you'd probably be able to handle a hundred stacks with a single operator dedicated to remote failure-handling.
VectorLock 8y ago
How big an expensive of a foundation do you think it would need? I can't even imagine that being a major cost driver, compared to other elements of the system.
- progfix 8y ago
  A foundation like for a skyscraper and they can get pretty big if the ground isn't rock.
  - bodas 8y ago
    But skyscrapers are built in economically beneficial areas, whereas you can build this thing anywhere.
  - VectorLock 8y ago
    I don't think it would have anywhere approaching the kind of foundation a skyscraper would have. A quick google search and it looks like a tower crane sites on a 1.5m x 6.5m square footing. So 6 of those. Assuming the soil can handle it and the 'energy' weights act as their own foundations.
CydeWeys 8y ago
> Someone needs to watch the stacking process. Why do you say that? We have fully automated CNC machines and 3D printers that can make things to amazing tolerances without human intervention. Stacking blocks neatly isn't a hard AI problem like self-driving cars are. > If there is a single error the whole tower can collaps and do a lot of damage. My reading of it is that the whole thing is fenced off anyway, since it contains an autonomous crane. Just put it somewhere that land isn't too valuable. If it all does collapse, the worst that can happen is it damages itself. Most wind turbines are similarly situated in places where, if they fail, there's nothing else really there to damage anyway. > Is the low-cost-concrete a strong enough building material? Presumably so, or if it's not, then it won't be used. I'd leave that to the engineers. > The generator needs cooling (in hydro pump it is cooled by the water flowing through) Cooling is not a hard problem. There are much larger plants generating way more power that operate 24/7 that handle cooling just fine. This idea is only generating as much power as a tower crane typically uses anyway, so whatever a tower crane has for cooling its motors should be fine. Probably some kind of closed loop liquid cooling system going to a big radiator with fans, like for a typical automobile engine.
- progfix 8y ago
  > CNC machines and 3D printers Those are very controlled environments. Outside where there is weather and wind, anything can happen. Also if there is a bug in the software or some hardware fails in a CNC machine then you loose some material, not a big of a deal. If the concrete tower collapses you loose a skyscraper volume full of concrete, also it takes days or weeks to clean the area up.
  - regularfry 8y ago
    I'm kinda surprised they're not talking about wrapping this thing in a cylindrical tower. Wouldn't add that much to the cost.

ebikelaw 8y ago

Everybody seems fixated on the stacking, but it's clearly not central to the system, merely an artifact of the demonstration-scale (and presumably demonstration-budget) implementation. They could just as easily be lifting a tremendously massive object a small distance and then letting it back down again with fixed hoists, which eliminates all of the structural problems this stack of barrels faces. Also, that would allow a single unit to sink and source power continuously instead of intermittently like this crane.

gitgud 8y ago
Yes, you could have 1 massive block, but the stresses and risks on the system would be much higher. Probably not achievable with current common tower cranes. The beauty of this idea is that these tower cranes are standardised and ubiquitous. So it could be implemented immediately in almost any city in the world.
foota 8y ago
I think the engineering there is more difficult because you need very strong cabling and pulleys that can deal with huge load.
- pas 8y ago
  Just use multiple attachment points. I think the problem with the one big weight is that it'd require an extra structure (a gantry) to hold it, whereas this is really simple logistically. Easy to transport and assemble.

adrianmonk 8y ago

It seems pretty easy to verify the blocks are stacked properly. First, make them out of a shape that naturally fits together. Then, build them with a vertical hole (shaft) through them. Put a reflector under the bottom one. Before the crane releases a block, it shines a light down the hole and checks if it is reflected back. Misalignment will block the light. (Or, you can do something similar with electricity, connected contacts on the top and bottom, and a check that current flows through the entire stack.)

kardos 8y ago
Sounds good except what do you do about biology that decides to take up residence in the holes?
- adrianmonk 8y ago
  I suppose you'd have to clean it regularly. When the crane goes to pick up a block, it could do the optical continuity check then too. If it fails, that indicates that either the block was moved after it was stacked correctly (unlikely but possible) or it got dirty. In that case, something comes along and cleans it. Maybe a rod-shaped brush (like a vacuum beater) that spins. Or a water jet. Also, you can have more than one hole for redundancy. If one of them is clear, that should be good enough. Hmm, or rather than holes through the middle, make them notches or grooves on the side and shine a laser through them.
progfix 8y ago
That only works in theory. In practice the reflector, light, whatever gets dirty and you would have false alarms non-stop.
saulrh 8y ago
Slap a tiny solar-powered GPS unit and transmitter on each block. ~$10 of electronics is marginal compared to the $2000 of concrete for each block. If any break, you already have a crane that you can use to move the block out of the way for repair; just hand it over to an operator who can do the special-case operation by hand. If you get a beacon unit with a MTBF of 10 years and not awful clustering you might get one to five failing per stack per day, so you'd probably be able to handle a hundred stacks with a single operator dedicated to remote failure-handling.

VectorLock 8y ago

How big an expensive of a foundation do you think it would need? I can't even imagine that being a major cost driver, compared to other elements of the system.

progfix 8y ago
A foundation like for a skyscraper and they can get pretty big if the ground isn't rock.
- bodas 8y ago
  But skyscrapers are built in economically beneficial areas, whereas you can build this thing anywhere.
- VectorLock 8y ago
  I don't think it would have anywhere approaching the kind of foundation a skyscraper would have. A quick google search and it looks like a tower crane sites on a 1.5m x 6.5m square footing. So 6 of those. Assuming the soil can handle it and the 'energy' weights act as their own foundations.

CydeWeys 8y ago

> Someone needs to watch the stacking process. Why do you say that? We have fully automated CNC machines and 3D printers that can make things to amazing tolerances without human intervention. Stacking blocks neatly isn't a hard AI problem like self-driving cars are. > If there is a single error the whole tower can collaps and do a lot of damage. My reading of it is that the whole thing is fenced off anyway, since it contains an autonomous crane. Just put it somewhere that land isn't too valuable. If it all does collapse, the worst that can happen is it damages itself. Most wind turbines are similarly situated in places where, if they fail, there's nothing else really there to damage anyway. > Is the low-cost-concrete a strong enough building material? Presumably so, or if it's not, then it won't be used. I'd leave that to the engineers. > The generator needs cooling (in hydro pump it is cooled by the water flowing through) Cooling is not a hard problem. There are much larger plants generating way more power that operate 24/7 that handle cooling just fine. This idea is only generating as much power as a tower crane typically uses anyway, so whatever a tower crane has for cooling its motors should be fine. Probably some kind of closed loop liquid cooling system going to a big radiator with fans, like for a typical automobile engine.

progfix 8y ago
> CNC machines and 3D printers Those are very controlled environments. Outside where there is weather and wind, anything can happen. Also if there is a bug in the software or some hardware fails in a CNC machine then you loose some material, not a big of a deal. If the concrete tower collapses you loose a skyscraper volume full of concrete, also it takes days or weeks to clean the area up.
- regularfry 8y ago
  I'm kinda surprised they're not talking about wrapping this thing in a cylindrical tower. Wouldn't add that much to the cost.