Better photovoltaic design by using fiber optics?

(Stevan White) #1

A way to increase photovoltaic efficiency using fiber optics?

One of the claimed inhibitors of efficiency was the band gap of materials which contrasts to that of a photon. My idea is a way to possibly mitigate this loss by increasing the frequency of the electricity being generated(?) and taking it directly to coil.

In a glass fiber from fiber optics, light bounces back and forth many times before finally exiting out the other end of the fiber optic thread.

What if you were to manufacture a fiber optic thread so that it has a thin copper coil embedded in it that would have a staggered patterned coating on bare copper of n type and p type silicon? Think n,p,n,p,n,p etc for the nano coating facing the light source. The copper winding would be encapsulated at this point to prevent energy leakage. The copper coil would not be tightly wound and would leave space for some of the light to reflect to the other parts of coil.
The nano silicon of p and n types would directly transfer the photovoltaic charge to the copper coil and it would remain homogenous to the coil. A secondary coil would be used (not coated with anything save for an insulator) to transfer the energy elsewhere. So basically this is induction.

Would the back and forth motion of electrical charges be sufficient for this to work?

Would the induction frequency occur near the speed of light?

(noboxes) #2

Sounds to me like your goal is to make the light bounce as much as possible and avoid the photons making any electricity on the pv material. And somehow you will get a static charge on one length of copper which will induce alternating current in another coil.

Are you aware a great deal of thought goes into pv panels, so there’s less light bouncing, less glass, shorter lengths of light travel, and making large flat surfaces to intercept the light asap? And it always puts out dc because that’s all it can do?

(Philip Mousley) #3

Always nice to see some out of the box thinking, however i do not think this one is viable. I am unsure what you mean by increasing the frequency of the electricity generated - the frequency of AC mains electricity is to do with the rate at which the direction of current flow switches per second. This is different to the frequency of an individual photon which is related to the amount of energy the photon contains. I think the former is irrelevant to the quantum efficiency of a solar cell, whilst the latter as you pointed out is controlled via the manipulation of the bandgaps present within the material.

I do not see how the multi-junction silicon would work, if you have multiple p-n junctions you cannot simply connect up either side of the device to collect the current. You need to add in extra layers to encourage quantum tunnelling between each p-n section (see for more detail). This is usually done when you are creating multiple junctions with different bandgaps, so that each layer can absorb a different part of the incident spectrum. However if all layers are just silicon, then this would be much less efficient that a single photoactive layer with some reflectors tuned to give photons multiple passes through the layer.

For induction to work you need to have an alternating magnetic field, which would require a changing electrical current (e.g. AC supply). As far as i know all solar cell designs can only produce DC because the energy levels within the materials are designed so that electrons flow to one side of the cell.

There would also be much to say about the difficulties in manufacturing and production of such a device, but i think on theoretical grounds it does not appear functional.

(Stevan White) #4

Here’s the drawing.

I think the difference in time between photons hitting different parts of the coil may help generate or simulate the AC.

I would like to try to test and see if this would work but obviously not by using materials on the Nano scale… that would be expensive.

Maybe to test concept by just using a glass rod or fused quartz rod and wrapping the coil around it with little pieces of n and p type silicon.
Where to buy these materials? I couldn’t just take pieces off of a solar cell because both types are bound I believe.

Thanks for taking the time to respond.

(noboxes) #5

I think you should send all your time and money developing this! The financial benefits of sharing your inevitable success with the computer industry would be incredible! I’ll bet Intel never thought of this when they were laying down pure copper nanotraces (like you describe) on their Coppermine series of CPUs!

I hope i am not treading on your patent, but will you set the copper spacing based on the wavelength of “cool” or “warm” white light?

(Stevan White) #6

I take no explicit claim and will not patent this. This is an open sourced idea. See a way to improve it? Patent your own variation? Knock yourself out.

It’s funny you’re the only one so far to make the data/computing capability connection with this concept!

(noboxes) #7

Well, computers use frequencies, right? And your idea can make a lot of the tall ones for free? Even right on top of the cpu? Good deal!

(Gordon Hoffman) #8

It would be great if someone solves the band gap issue. I’ve read a report on an attempt to alter wave lengths so that a full spectrum of light can be changed into the more productive wave lengths. The only original thought I had on improving the efficiency of a solar array is to make smaller (4 - 6 inches square) high voltage cells (60 volt nominal) for a 48 volt battery system. In my case, I want to cover a curved top of a three wheeled, leaning, human/electric vehicle, so that I can maintain full power on the cells pointing most directly at the sun. Also, one bird poop wouldn’t shut down the whole array. Each cell would need it’s own MPPT circuit, but those could be small, low current circuits - and hopefully not too expensive. Then you would only need a simple charge controller. But, I don’t even know who to ask to help build such a thing, or if it would be a good idea to try.

(noboxes) #9

What P-N junction do you know of that will make 60v when photons hit it?

I have been following solar energy in general since the early 1970’s, and the best chance of efficiency i have seen is only recently, in overlaying translucent cells that respond to different sunlight frequencies (UV, visable, and IR). I don’t expect to see them in production. Might help to glue IR cells to the back of the normal blue ones, BUT if you get the blue ones hot enough to heat the IR cells, the output of the blue ones will tank.

Way easier to build the best vehicle, and then tilt the panels around the long axis of the vehicle separately. The edge-on wind resistance of a panel as you are driving is almost nothing. Who wants to drive a car that’s leaning sideways just so the panel can try to get more sunlight?

(noboxes) #10

As long as people are still putting up stupidities like

we won’t need fantastical artsy CGI designs, or pricey outlandish speculation, or even new technology.

(Gordon Hoffman) #11

Nice carport! I wouldn’t have one when I got to work, and that’s why I would take mine with me. And my array would be the top/cover of the vehicle - hopefully arranged in a low drag configuration.
One junction wouldn’t be 60 volts, but the cluster of cells to make the small square panel could be. I might need a bigger format to discuss the nuances of the design. There’s one Italian company that is doing something close to what I’m talking about, on about a 2 foot square panel - they are using one of the spaces for the cells to house the MPPT controller - it was mounted on the top of a motorhome too (if I see it again I’ll send a link).

(noboxes) #12

But it’s NOT nice! Half the car is still in the direct sun, the posts are way too close to the car, the panels are not sun tracking, and to recharge the car in the few daylight hours when the owner is home there is not enough panels.

Seriously, put the posts at the corners of the array, then turn the entire thing 90 degrees, so the posts aren’t an obstacle course to back the car between. And the way it’s placed in the parking area, there’s not really enough room on either side to park a 2nd car, or even a motorcycle.

At that sun angle, half the max rated power of the panels is not being used, or to put it another way, the owner is paying twice as much for the power they are getting. Panels must be dead-on to the sun to get full output. And there’s only one kw of panels there anyhow, or after MMPT and battery inefficiencies, one useable driveable hp-hr if the sun is directly over the panels.

A good install is not about the pretty shade of blue or perfect paint job on the posts.

It’s more cost effective to not put the heat-producing controller in with the cells, but to mount it somewhere else. Anywhere else. Anywhere it’s not heating the cells. Anywhere the sun isn’t directly heating the controller.

Did you sketch it out, so you can see that when one edge of your domed roof is pointed directly at the sun, the opposite edge is barely putting out any power at all, but you paid just as much for the ones not putting out power?

Then just use any panels you find, and wire them in series to get the voltage you want. For instance, ten panels of 17v each wired in series is perfect to cheaply direct convert to 120vac. But finding or custom making a bunch of small 170v panels is rediculous.

(.) #13

In my opinion; it would be a good thing to try.
I often think about solar powered electric propulsion, mostly for a boat.
Wheeled vehicle is similar.
I came to the conclusion, that I want many smaller panels instead of few larger panel.
The advantage, I see, of smaller panels, they can be removed and stored under the deck,
in case of adverse weather. The other advantage is the smaller panels can be connected
in series or parallel mode.
When there is not enough sunlight for the panel to produce 12V , a 12V battery would not
be charged to max capacity. 9V charging voltage will not charge the battery to 12V.
But when the panels can be switched to series circuitry, the 2 9V will add to 18V and that
would charge to full capacity of a 12V battery, provided there is enough current and time.
So the sacrifice of current and longer time makes it possible to charge, when otherwise
it would not be possible to charge. This could work with other voltages too.

(noboxes) #14

(Gordon Hoffman) #15

The solar carport is unsightly, but maybe it is large enough to make a usable amount of power. There is not enough surface area on top of a car to make enough power to push a vehicle of that weight. BMW put a panel on top of one of their cars to run a ventilation fan. Another problem of mounting panels directly to the top of a roof is that they get hot and transfer heat to the inside (of a car, motorhome, or a house), increasing the air conditioning load. A worthy vehicle would need to weigh about 150 pounds - so the panels would have to be lightweight too.

I have 3 - 24 volt panels on my house, in series, sending 72 volts to my charge controller, which is converted to the correct voltage for my 24 volt battery bank. One bird poop affects the entire array. Smaller panels of 60 volts wired in parallel might be very effective (IMHO).

And thanks for posting those links. I read everything I can about solar power, and sometimes questions don’t get answered in the Home Power magazine.

(Gordon Hoffman) #16

(noboxes) #17

We are a lil offtopic here, discussing electric cars on an insane thread of putting fiber optics between the sun and the solar cells on boats… but…, you almost drew a Sparrow, which may now be known as something else or perhaps something newer. The newest oem for the Sparrow is in Canada, and the newer Sparrow is slightly different, and maybe half the price.

I am pretty sure in the usa it will need to be heavier, and i since i have a few golfcart transaxles out in the barn, and some forklift motors, and some deep cycle batteries (one is powering this desktop computer right now), and etc etc etc, you cannot build an electric car as light as 150 pounds. And that’s a good thing, because if you could, the first 18-wheeler that passed you on the interstate highway would blow you off the pavement.

For what it’s worth, the original Sparrow had an optional trailer with a generator on it, for long drives. That company also had a couple of unique gasoline powered cars. When i saw that, i wanted the car, and if i lived in a small town (no way!) i would still want one.

There was once a start-up electric car company in Tampa in the early 1970’s. I tried to get a job there, they weren’t hiring, and they folded. Prolly a good thing, found out later they had some design problems rooted in the 1960’s Detroit way of thinking.

(noboxes) #18

Individual (one for each panel) max power controllers should help. In the olden daze, a bird flying over could cause all the magic smoke to leak out of the panels it’s shadow landed on. A diode on each panel to prevent reverse current helped a lot. With all the high tech available in the last 20 years, i am still amazed that one of the biggest operating expenses of a solar farm is the guy driving around in his truck, with a water tank and a soft brush on a stick, manually cleaning the panels or mirrors.