Half a croissant, on a plate, with a sign in front of it saying '50c'
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passive solar street lights

fibre optic
  [vote for,

Bundles of fibre optic cable are laid around the globe, with each strand being half a circumference long. One end of each fiber is attached to a large diffuse reflector facing the sky. The other end is fitted to a downward pointing diffuser on a long stick.
pocmloc, Sep 10 2020

inspiration one big light source - many streetlights
[pocmloc, Sep 10 2020]

Site of Waitangi Solar Collector https://www.geodato...ipodes/france/paris
[bs0u0155, Sep 10 2020]

Chatham Islands, home of Waitangi https://web.sll.fi/mpe/chatham/
[bs0u0155, Sep 10 2020]

Passive - Aggressive Infra-Red Detector Passive_20-_20Aggre...nfra-Red_20Detector
Prior Art [8th of 7, Sep 12 2020]

Peter Sellers' Rolls-Royce https://www.google....uCtgznyhhUzGp0hZ8xG
Fault-finding the Goon Show way ... [8th of 7, Sep 12 2020]


       Sheer genius. [+]   

       Almost no running costs ! Only the capital cost of installation, and a small amount of maintenance - just keeping the inputs and outputs clean.   

       It would make sense to pipe light from areas with a surplus of light - the Namib, Sahara, Gobi etc. through concentrators, and run a big, thick fibre to the destination where a splitter shares out the illumination to individual units.
8th of 7, Sep 10 2020

       For applications where lots of power are being routed, fiber optics become saturated and instead the solution is often something called a liquid light guide. Even they start to get unwieldy in the kW range which is very much low end for both sunlight and even the most modest of urban lighting projects. If you want to move a lot of light, and you don't really care about coherence, spectral shift etc. then angled mirrors and straight lines are the way to go.   

       Lets work through a pilot project to check feasibility. Take the small community of Waitangi in the Chatham islands <link>. As the community is small & remote the electrical infrastructure is likely to be inefficient diesel/lpg generators etc. likely reliant on ships to resupply. Even at a large capital cost, I imagine the New Zealand government would entertain a sustainable, low- carbon solution to street lighting that would need almost no maintenance.   

       For Waitangi, we will need a solar collector on the opposite side of the globe (antipode) <link>. To account for atmospheric, mirror & misalignment losses, I think that covering a few hundred square km of Paris would do the job nicely. Then, it's just an orbital mirror or two in the appropriate orbits and the good citizens of Waitangi can walk the streets at night in comfort. I can't see the downside to this scheme.   

       In researching this study I stumbled upon the Chatham Islands website <link> an absolute gem of an internet fossil.
bs0u0155, Sep 10 2020

       // covering a few hundred square km of Paris would do the job nicely //   

       Well, that could be done anyway, and then if it can also be used to provide lighting for Waitangi that would be a bonus.
8th of 7, Sep 10 2020

       Is Waitangi in dire need of high-contrast rat silhouettes?
lurch, Sep 12 2020

       If we just fibre optic-ed every inch of the planet to its antipode we'd become invisiball.   

       If you could find a way to make these passive solar street lights dim in an annoying way as people or cars approach them you could market them as “passive aggressive solar street lights“
hippo, Sep 12 2020

8th of 7, Sep 12 2020

       Perhaps both ends could be on a long stick, with the diffusers pointing up at one end during the day, and down during the night. This would halve the number of fibres needed and mean that street lights would be "twinned" with ones approx 12 hours away.   

       The fibres may not need to be as long as you think, since you don't need to go half a world away - you can stay at the same latitude, provided you are well clear of the arctic/antarctic circle.
Lemon, Sep 12 2020

       Possibly the idear of the yea. [+]
pertinax, Sep 12 2020

       Nice idea to have 2-way fibres. Could there be a passive switch to flip the incoming/outgoing light? Probably not.   

       And I would think there could be some kind of optimisation algorithm about how long the fibers need to be. Especially if the lights don't need to be on all night but only sunset to midnight and 6am to sunrise (for example)
pocmloc, Sep 12 2020

       Watches pocmloc tooling around in gold Rolls- Royce, from the gutter, remember me, your old pall Nmrm...
not_morrison_rm, Sep 12 2020

       // gold Rolls- Royce //   

8th of 7, Sep 12 2020

       All we need is three balloons about the size of the moon, and some small tubs to keep them in orbit. Of course the astronomers won't like it, but we can just give them some cameras on the dark side of the balloons to shut them up.
Voice, Sep 13 2020

       [nmrm] I will always keep coming back to where you are lying there in the gutter, as long as you still have that rag and the hubcaps still need polishing. Its a very useful service you provide. Cheap too!
pocmloc, Sep 13 2020


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