Fiber optic solar transmission and tank lighting applications

[RMc]

Fiber Optic Solar Condensers and tank lighting applications

I think we can agree that tank lighting is one of the most controversial topics in reefkeeping. I think if we had the $ to front the electric bill and ability to export heat we’d all be using metal halide. It isn’t because it’s the most efficient, but because it most closely approximates real sunlight. There’s just no way around it… if you want full spectrum light, you have to pay for the power.

But, what if we used fiber optic condensers to channel light from a nearby window – or better yet roof top array. Not too many people want to cut holes in their ceilings for solar tubes; fiber optic condensers could be a great, non-invasive method to get natural sunlight into your tank.

These systems are a bit expensive, but maybe there’s a DIY solution that we could start playing with.

http://www.sunlight-direct.com/
http://www.monotsukuri.net/japan/himawari/himawari.htm

There are a lot of unanswered questions here, like whether the fiber can truly transmit broad spectrum light, what the losses are, and what array size you'd need to get started.

 

[this is me]

I would go solar tube before looking into this. The installation on solar tube is easier and would cost considerably less. However, judging by where we are, going solar will unlikely work out for what I'm keeping(SPS dominant). And also, I like my tank to be lit when I'm home and not at work.
Here's a lengthy thread on solar tube. I don't know what happen in between the time he installed the tube and the latest post but all of his sps are gone and he did stated that it didn't work out so well for sps. I'm sorry, but if I'm doing a large tank, it'll better be more than a tank full of sea fans and gorgonians.
http://reefcentral.com/forums/showthread.php?t=1457056

 

[RMc]

Just to get minds ticking - a large fresnel lens (cheap - or free from an old big screen TV) could be used for the main collector.




A one sided convex focusing lens like those used for 20-100W multichip LED's could be used to force the cone of light back into a parallel beam. This light would then travel into a thick bundle of unjacketed fiber optic cable. I assume we'd want cheap stuff since we're not targeting a specific wavelength. Unfortunately, since it would be a broad spectrum of light entering the tubes, we'd have a lot of leakage - so the cable couldn't have any sharp bends or kinks.

On the other end, we'd have a reversed fresnel lens above the tank to redirect the light back down.

 

[Flame Angel]

Just to get minds ticking - a large fresnel lens (cheap - or free from an old big screen TV) could be used for the main collector.

View attachment 93825


A one sided convex focusing lens like those used for 20-100W multichip LED's could be used to force the cone of light back into a parallel beam. This light would then travel into a thick bundle of unjacketed fiber optic cable. I assume we'd want cheap stuff since we're not targeting a specific wavelength. Unfortunately, since it would be a broad spectrum of light entering the tubes, we'd have a lot of leakage - so the cable couldn't have any sharp bends or kinks.

On the other end, we'd have a reversed fresnel lens above the tank to redirect the light back down.

There was a guy on "Doomsday Preppers" that built something like what your picture has. He used it to boil water and cook meat.

Might want to test it before using as lighting.

 

[panayiote73]

Skeptical on the physics. Light directly from the source i.e. sun, or MH bulb is a lot different than light defracted from a lens or mirror. Something is always lost. Not to mention here in the NE we get very little direct sunlight, especially this time of year.

 

[RMc]

The fresnel lens will have minimal effect on the median spectrum we're after - far UV and IR may be curtailed, but the middle won't change. It's like light hitting the surface of the water - the refraction itself has no effect on the content, but the filtration of light through the water column does. Physics wise, we will likely lose some intensity in transmitting the light through the fiber, but as long as the run is relatively straight the losses will be minimal. Think of it this way; fiber is used to transmit data (binary) signals over hundreds of miles with relatively no losses at all. The signal is just "light" of a specific frequency.

 

[cilyjr]

Also let's bring into the equation the Riddle article is it really natural light we want.
Many animals we keep are collected from depths where they have grown accustomed to very different light than what is at just below the surface.

The article for those who have not seen it. I know the op has
http://www.advancedaquarist.com/2013/12/lighting

 

[Fishport]

It's fun to see this type of thinking. You can't get around the climate limitations on such a light source. But in the interest of sustainability, perhaps a hybrid system with a smart dimmer on LEDS could use sunlights as a supplement to LEDs, thereby taking advantage of what "el sol" has to offer.

It was an interestng article except I found that it didn't provide a conclusive argument for the answer to the question. The biggest unknown with wild coral is what depth and amount of shading existed at their source location. Cultured coral may adapt to varying lights. The issue is how not to harm corals wiith the targeted light spectrums LED offers. For example, consider the points raised in this passage from Dana Riddle's just published article article, Ultraviolet Radiation and Aquarium Lghting
http://www.aquarium-design.com/reef/uvlighting.html

Biological Effects of Ultraviolet Radiation

It has long been recognized that UV radiation penetrates natural waters
(Jerlov, 1950; 1976). Lewis (1995) noted that reef organisms employ
several mechanisms to protect themselves from UV: avoidance, protection
and repair. Obviously, many corals colonize areas with relatively high UV
energy, so they have measures to protect themselves. Shibata (1969)
found UV-absorbing pigments in certain Staghorn corals (Acropora) and
Cauliflower corals (Pocillopora) as well as a blue-green alga. He speculated
that a compound he called S-320 (meaning it absorbed UV energy at and
around 320 nm) might protect marine organisms from ultraviolet energy
penetrating shallow water. An even earlier researcher, (Kawaguti, 1944)
speculated that some coral pigments offered protection against “strong
sunlight.” Jokiel (1980) was perhaps the first to report UV as an important
ecological factor on shallow water tropical ecosystems. Together, these
papers along with others suggested that UV radiation could have deleterious
effects on coral reef communities.

When I read this it made me wonder whether our delight in stimulating fluoescence pigments is shared by the corals who developed this ability to protect themselves. On the other hand if there is also some other physiological benefit to fluorescence such as attracting zooplankton or being able to colonize locations that other corals avoid, then we and the corals can enjoy the glow.

Sorry to have taken such a long digression from the threads topic. I believe it ties back in that there is still so much to learn aboout meeting coral light requirements and how we can use new technological tools,whether LEDs or fiber optics to advance our reefer accomplishments.