Why this subject? Well, the Nexus has many a brilliant minds from all sorts of professions, so I thought I would ask some piece of advice on some mechanical aspects.

The story goes as follows:

I was talking to a guy the other day, he is trying to make some developings
on the solar energy capture technology.

This guy was stating that photovoltaics are not that good, and that they capture maximum
20% of the sun's potential energy. Plus they need some sort of maintenance that could
make them not very efficient for developing countries.

But anyway, he was saying that he's working on a solar parabolic disk. This is mega
powerful in capturing above 90% of the sun's energy. The disk can be 1-2 meters in
diameter, and it focuses all the harvested rays on a single point which it heats up
easily above 350 C). This energy can be utilised in millions of different ways (e.g.
converting to electrical). Actually he was talking about distilling sea water to pure
water and the generated steam can be coupled to an electicity generator. So, you get pure
water PLUS stored electricity from the steam.

There is one big problem though:

There needs to be a good tracking device that will be able to move the solar parabolic
dish along the sun's orbit. The disk needs to be always positioned with respect to the sun so that it can effectively focus the rays to the collector. A static disk will get energy only 1-2 hours per sunny day, this is not very efficient. So, this guy is trying to develop some easy (i.e. not involving expensive and complicated computer-manipulated motor driven incidence-tracking device) automatic tracking system for the plate, so sun can be harvested during the whole daylight.

Now, as a biologist I proposed him that plants have excellent and amazing sun tracking mechanisms; Especially the sunflower, which is the king of heliotropism.

Now comes the mechanical problems:

1) Could one couple the solar disk to a plant using a fairly easy and simple to maintain system?

2) Would that be easy to imitate the system that plants harness for heliotropism?

Note that not much are known about the mechanics of heliotropisms in plant. It seems however that water accumulates on the shady side of the stem, and as the pressure builds up, it forces the head in a steady arc toward the light. This force is enough to move a large surface in a 180-degree arc.

Any suggestions are highly appreciated.

Recently there was IMHO a major development that created a very cheap solution to concentrate solar power:



You can find more information on this link:
http://www.coolearthsolar.com/technology

Parabolic type collectors already exist, I've seen a few around, has he checked out the competition? I stumbled upon a few when I was trying to source some PVs a while back, but I don't have the links.

I'm sure sun-tracking devices are around already, but if you might be able to make something better definitely go for it!

Last I heard solar dyes could be replacing the current PV technology, maybe check out that technology too?

a one hundred and eighty degree array of small inexpensive solar panels(very small) up to eight...coorisponding to sun position...when each individual panel is aligned with the sun it will create a charge greater than the rest of the array...therefore closing a low voltage relay switch coorisponding to that particular direction

as the sun pans across the sky each direction specific solar panel will align your parabolic dish or photovoltaic array to that direction

and it would be really cheap to do

what about a transparent(maybe glass) sphere designed to concentrate the light in the center wherever it may come from? in the middle one could have another little sphere which captures the heat and transmits it through some sort of metal stem. one could position these spheres very high in the air so that they will capture the light more efficiently. just an idea.. i'm not a physicist so it could also be total bullshit.

I watched a television show recently. I think it was called Ecopolis or something on the Science channel. A man in Australia has already invented something just like this. I believe it's parabolic (that's like satellite dishes, right?) and comprised of a bunch of mirrors. It even tracks the sun too and captures close to 100% of the energy that reaches it. Of course, it's effective in Australia because apparently they get more sunshine.

It's called a heliostat ...

Nice website explains construction and gives help:

http://www.iwilltry.org/...ar-heating-and-lighting/

Infundibulum,

I think the most recent "state of the art" solar power generator is a device similar to what you describe--except it's formed from a small array of parabolic mirrors all held on a frame which tracks the sun. The heat beam is concentrated on a stirling engine, which directly produces the electricity.

The main electrical utility in California has already contracted for many thousands of these to be arrrayed in the desert in several locations outside of Los Angelos and San Diego.

Here are some vids about them:

25KW

10KW