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Is it possible to pipe free sunlight into a vertical farm using fiber?

by bloat 11y ago

maliker 11y ago
You would need a fiber collection area the same size as the total floor space of your vertical farm. So it would have to be absolutely massive.
- scott_karana 11y ago
  Well, if the intensity of light in your locale is double what you need, couldn't you diffuse it with a lens/prism system accordingly? Eg, if you're growing a mild-sunlight plant in high-sunlight climes like arizona, you could have a collection grid half the size of the delivery grid.
- e12e 11y ago
  So, this sounds like it could be great for very arid areas, where it might be easy(?) to build a massive solar farm in the desert, and run a cable to the city -- but not sustainable to water the same area where one can put solar? Switch solar for wind turbines in areas with little sun light and strong winds. I wonder if it would be any easier to recycle water in a city/building than if used for "normal" farming?
tagawa 11y ago
I'm based at a university where there are a couple of solar-tracking devices feeding fibre optic cables to a corridor in a nearby building. The light from the 1 metre-wide trackers is laughable. You can see the light source but it's not strong enough to practically illuminate anything. Maybe this is an old installation and the technology has since improved, but my instinct is that solar panels powering batteries to light LEDs would be much more efficient.
exelius 11y ago
No, but it is possible to convert that sunlight into solar energy and use that to power LEDs. More efficient too; since you can use LEDs that emit the proper spectrum for the plants you're growing.
- dragonwriter 11y ago
  > No, but it is possible to convert that sunlight into solar energy and use that to power LEDs. More efficient too; since you can use LEDs that emit the proper spectrum for the plants you're growing. Citation needed on the "more efficient" part. Sure, if you assume that the photovoltaics, transmission systems, and LED lights themselves are all 100% efficient (and that there is no energy cost to maintain any of those systems) so that you are transforming the spectrum for free, it would be more efficient, but none of those things are true, and some of them are very far from true.
  - exelius 11y ago
    Sorry; I meant "potentially more efficient". Anything relating to vertical farming is decades away from being commercially viable on a large scale; so it's not a crazy assumption that the efficiency of all those systems will be greatly improved by then. Regardless, most plants utilize only a small part of the light spectrum. Photovoltaics can capture a much, much larger spectrum and convert it to electricity. They don't need to be 100% efficient; just efficient enough that they can deliver all the parts of the spectrum that plants use without any of the parts they don't.
cousin_it 11y ago
1 sq km of vertical farm + 1 sq km of sunlight collectors = worse in every way than 1 sq km of horizontal farm. And that's assuming perfect efficiency, which is wildly unrealistic.
- giltleaf 11y ago
  Not true if you count for the negative externalities of the horizontal farm and the fact that the vertical farm is producing way more food.
  - cousin_it 11y ago
    Do you think 1 sq km of farmland causes more negative externalities than building and maintaining a skyscraper + 1 sq km of solar panels? That sounds really implausible, can you explain a bit?

Is it possible to pipe free sunlight into a vertical farm using fiber?

by bloat 11y ago

Is it possible to pipe free sunlight into a vertical farm using fiber?

You would need a fiber collection area the same size as the total floor space of your vertical farm. So it would have to be absolutely massive.

scott_karana 11y ago
Well, if the intensity of light in your locale is double what you need, couldn't you diffuse it with a lens/prism system accordingly? Eg, if you're growing a mild-sunlight plant in high-sunlight climes like arizona, you could have a collection grid half the size of the delivery grid.
e12e 11y ago
So, this sounds like it could be great for very arid areas, where it might be easy(?) to build a massive solar farm in the desert, and run a cable to the city -- but not sustainable to water the same area where one can put solar? Switch solar for wind turbines in areas with little sun light and strong winds. I wonder if it would be any easier to recycle water in a city/building than if used for "normal" farming?

tagawa 11y ago

I'm based at a university where there are a couple of solar-tracking devices feeding fibre optic cables to a corridor in a nearby building. The light from the 1 metre-wide trackers is laughable. You can see the light source but it's not strong enough to practically illuminate anything. Maybe this is an old installation and the technology has since improved, but my instinct is that solar panels powering batteries to light LEDs would be much more efficient.

exelius 11y ago

No, but it is possible to convert that sunlight into solar energy and use that to power LEDs. More efficient too; since you can use LEDs that emit the proper spectrum for the plants you're growing.

dragonwriter 11y ago
> No, but it is possible to convert that sunlight into solar energy and use that to power LEDs. More efficient too; since you can use LEDs that emit the proper spectrum for the plants you're growing. Citation needed on the "more efficient" part. Sure, if you assume that the photovoltaics, transmission systems, and LED lights themselves are all 100% efficient (and that there is no energy cost to maintain any of those systems) so that you are transforming the spectrum for free, it would be more efficient, but none of those things are true, and some of them are very far from true.
- exelius 11y ago
  Sorry; I meant "potentially more efficient". Anything relating to vertical farming is decades away from being commercially viable on a large scale; so it's not a crazy assumption that the efficiency of all those systems will be greatly improved by then. Regardless, most plants utilize only a small part of the light spectrum. Photovoltaics can capture a much, much larger spectrum and convert it to electricity. They don't need to be 100% efficient; just efficient enough that they can deliver all the parts of the spectrum that plants use without any of the parts they don't.

cousin_it 11y ago

1 sq km of vertical farm + 1 sq km of sunlight collectors = worse in every way than 1 sq km of horizontal farm. And that's assuming perfect efficiency, which is wildly unrealistic.

giltleaf 11y ago
Not true if you count for the negative externalities of the horizontal farm and the fact that the vertical farm is producing way more food.
- cousin_it 11y ago
  Do you think 1 sq km of farmland causes more negative externalities than building and maintaining a skyscraper + 1 sq km of solar panels? That sounds really implausible, can you explain a bit?