BS: Solar Power big improvement at last

Subject: BS: Solar Power big improvement at last
From: Keef
Date: 18 Mar 06 - 05:22 AM

The cost of solar voltaic panels has been stuck on about $20 per watt for about 20 years. With the cost of all other silicon based products (processors, memory etc) having improved in cost/ performance by a factor of thousands over the same period this might start to look like an energy cartel conspiracy.
An Aussie inventor has come up with an idea that gives approximately 5 times more watt hours per day than a similar priced conventional panel.
The idea uses a low cost fresnel lens to concentrate the suns rays onto a fairly small area of photocells plus an intelligent tracking mechanism to follow the sun all day. I wonder how far this idea will go before it mysteriously vanishes like so many other inventions that might upset the status quo?
http://www.abc.net.au/newinventors/txt/s1487858.htm

Subject: RE: BS: Solar Power big improvement at last
From: Pied Piper
Date: 18 Mar 06 - 06:14 AM

Thanks for the link Keef I'd thought along similar lines myself but using a Fresnel lens is a great solution.
The day will come when sustainable distributed power systems will be adopted because; in the long run there is no alternative. The power companies and governments have a vested interest in keeping us dependent on centralised power supply the utilities because they have an unwritten cartel and the authorities because they want to be able to cut off our supplies easily when we get stropy. In the UK the whole national grid is controlled from 2 sites, which in an age of terrorism is insane.
Imagine a system with thousands of small sustainable generation points, contributing power to a grid with relatively small local energy storage systems to smooth out supplies and cope with variable demand. It would be more flexible and reliable but almost impossible to use as a weapon of extortion.

PP

Subject: RE: BS: Solar Power big improvement at last
From: The Fooles Troupe
Date: 18 Mar 06 - 06:55 AM

Currently (pardon the pun!) research is going on with electrolyte type solar cells, which require a bunch of small beads of one chemical immersed in a solution of an electrolyte. Efficiency is only about 4% in the prototypes, but they believe that they can eventually obtain higher efficiencies than silicon solar cells - the back of the cell is mirror reflective to help reflect any light that bypasses the bed of beads.

Subject: RE: BS: Solar Power big improvement at last
From: Amos
Date: 18 Mar 06 - 09:24 AM

It's a good scheme, that! If you had an array of eight of them you'd about have the house powered, using Sydney's exposure. I'd think it would be useful to capture the excess heat in a coil of copper tubing to pre-heat your hot-water tank. No sense wasting it! :)

A

Subject: RE: BS: Solar Power big improvement at last
From: Alice
Date: 18 Mar 06 - 09:26 AM

Back in the late 1970's when I was doing renewable energy public awareness campaigns, I remember lecturing on the beads of silicon in a solution - at the time it was an idea of the inventor of the Texas Instruments hand held calculator. The beads, created by putting molten silicon through a pilling (shotting) tower, solved the problem of the amount (cost) of silicon needed in rolled or sliced cells. Also, if a connection from one cell to the next was lost, you have a problem there, but the silicon beads in a solution did not have to connect to each other the way a system of connected cells did.

Alice

Subject: RE: BS: Solar Power big improvement at last
From: Rapparee
Date: 18 Mar 06 - 10:11 AM

Hmmm...could recycled silicon from old computers be used? Could the tracking components be recycled from old PCs? Could an old PC -- say an 8088 or earlier -- be used for the "follow the sun" controller?

This would work out here quite well; we have LOTS of sun during the years (although not right now!).

I think that decentralization -- of energy, of government, of many things -- is part of the ultimate solution to many of our problems.

Subject: RE: BS: Solar Power big improvement at last
From: GUEST
Date: 18 Mar 06 - 06:02 PM

This is definitely not a new idea. Several Solar concentrators using Fresnel lenses were built around 1980 using U. S. government funding and none of them worked nearly as well as ancicipated. The added cost of optics, tracking devices and cooling equipment outweighed the savings in silicon.

There were large concentrating solar arrays built at Sky Harbor Airport in Phoenix, at Dallas-Ft. Worth Airport, on the roofs of a buildings in Albuqueque, New Mexico and Oklahoma City and at a Junior College in Arkansas, among others.

That being said, it still might be a good idea if properly pursued.

Bev and Jerry

Subject: RE: BS: Solar Power big improvement at last
From: GUEST,Robomatic
Date: 18 Mar 06 - 10:19 PM

There is great progress being made in Solar Voltaics. Saw an interview of a couple who are manufacturing great quantities of solar generating material which, while not as efficient as silicon solar cells, are amorphous, i.e. in the real world they can take a lot of punishment and still put out voltage. They can manufacture it in great long strips of stuff, and it is effective out of direct sunlight.

In addition, there is the 'big concept' version of solar power, putting satellites in space to accumulate raw sunlight and convert it to microwaves and beam it back to earth. This is perfect for generating huge government subsidies in the near future.

Nice topic

Subject: RE: BS: Solar Power big improvement at last
From: The Fooles Troupe
Date: 18 Mar 06 - 11:47 PM

'in space' - read the Sci-Fi stores decades ago - One of the 'I Robot' stories involved giving the robots religion, didn't it? :-)

Subject: RE: BS: Solar Power big improvement at last
From: Keef
Date: 19 Mar 06 - 02:22 AM

Have to agree, it is not a new idea. From my own dabbling in solar power it is apparent that correct alignment with the sun i.e. active tracking yields at least a doubling of energy gained through the day.
Rated power reduces considerably with temperature rise, this is the reason that the sunball does not incorporate solar water heating.
BTW I have no connection with this company whatsoever, just an interest in trying to save the only planet we have.
From what I can see on the website this is a simple idea that could really make a difference.
It used to be the case that peak power here in Australia was during the winter when all the heaters were turned on.
Now that we can buy an air conditioner from Harvey Norman for less than $500 dollars (hard to resist this last summer) the peak demand in midsummer has caused overloads all over the country.
The cost of increased infrastructure to support the additional load is estimated at about $3000 per air conditioner. That is not taking any account of the increased emissions needed to power the new coal powered generators.
This simple little idea is a here and now solution.
If a tiny fraction of the money that was used to subsidise the nuclear industry was chanelled into solar, then we would all have free power and less nasty toxic waste and big go bang thingies.
Here is another plug for my cause of the day.

http://www.greenandgoldenergy.com.au/

Subject: RE: BS: Solar Power big improvement at last
From: Bert
Date: 19 Mar 06 - 02:26 AM

I have a friend who designed a solar air conditioner but couldn't get financing to bring it to the market.

Subject: RE: BS: Solar Power big improvement at last
From: Bunnahabhain
Date: 19 Mar 06 - 07:12 AM

Keef,

Solar power is how to run an Air conditioner. In hot, sunny climates, where they are very common, the biggest load on the power system is in the middle of the day, when solar cells work best. If it's cloudy, then the A/C demand drops.

This link is to a big , New solar power project in Southen California.
Big Solar power set-up

Subject: RE: BS: Solar Power big improvement at last
From: The Fooles Troupe
Date: 19 Mar 06 - 07:13 AM

You can now buy 'heat pump' hot water heaters in Australia, but at a thousand dollars, it's a bit out of my price reach - even though they supposedly cost less to run - and electric rate 33 is 'switched' and cheaper than normal rate. I also turn it off if I am going away for more than a day or two.

Subject: RE: BS: Solar Power big improvement at last
From: JohnInKansas
Date: 19 Mar 06 - 07:31 AM

A few links that I've had on file:

US Dept of Energy: National Center for Photovoltaics

National Solar Supply Co. (Commercial stuff you can buy now.)

Southwest Photovoltaic (More stuff you can buy now.)

My link, a few months old, to US DOE information on storage batteries for PV electric systems now takes me to a "redirect" site for a variety of info from the new UD EOE "Energy Efficiency and Renewable Energy" (EERE) dept. Since this page gives a number of categories of info, with links, it may be useful, although I haven't run the new links:

US DOE EERE Redirects

Lots of links also at EERE Home Page

The "Batteries" link that was deleted (when they reorganized things in response to Bushie's recent speech perhaps?) can be found at NREL Battery Power for Residential Solar Energy (.pdf 351 KB) Before discussing dispersed photovolaic power you really need some understanding of the "peripherals" that go with solar panel power supplies, so I'd strongly urge looking at this one if you want to speak coherently on the subject. It's "consumer grade" info, and not up to what I'd want to know before laying out cash, but gives a general concept.

As noted, the use of Fresnel lenses and sun-tracking arrays/collectors is nothing particularly new. Attempts date back at least to the 1950s.

While the "patterns" that do the focusing in Fresnel lenses are not necessarily at optical wavelength scale, they tend to be very fine, and are easily disrupted by fairly small amounts of dust, dirt. smog, birdshit, insect spit, and other contaminants. It costs money to do frequent maintenance, even if it's just "washing windows," and previous Fresnel systems have been only moderately useful due to extremely high maintenance costs. Reflector panels are frequently used, and provide similar boosts in collection area without increasing the size of the PV panels. The boost with passive reflectors is a bit less than with Fresnel focusing, but it doesn't require tracking, and requires much less maintenance.

Sun follower systems have also shown some marginal improvement in raw numbers for efficiency, but are suited only for fairly low power uses. If significant (whole house power) sizes of installations are needed, it generally has been much more cost effective – in total lifetime cost of ownership – just to use more collecter panels and add simple fixed/passive reflectors.

It is almost a given, that a Fresnel collector requires a sun-follower method, and the combined cost of maintaining both has made such systems "unattractive."

It's a lot easier to build a large solar power installation that it is to obtain cost-effective installation in sizes appropriate to single-home use.

Few people may have noted, and it's not obvious unless someone reminds you, that most photovoltaic elements respond only to a certain specific wavelength of ambient light. Unless the incoming photon is a close match to the frequency of the electron transition that produces the voltage, it does nothing except heat up the panel. Heat reduces the efficiency of the panel for the conversion of the light that it can trap and convert. Some commercially available panel systems incorporate "passive heat" units that absorb the heat from the wavelengths that the PV element can't absorb and convert to electric power. This improves the efficiency of the PV elements, by keeping them cooler, but the PV electric generating system must be integrated with a solar heat system that can use, or store for later use, the removed heat in order to maintain continuous efficient heat removal along with the electric generation.

The same frequency dependent PV conversion is used in a few laboratory version PV elements that use multi-layer structures. The frequency appropriate to the top layer is reflected back into that layer, and the frequencies appropriate to other subsequent layer are passed by "color filters" built into the device. Thus far, only a few "frequency bands" can be built into efficient PV devices, but the potential improvement in overall conversion, for a given ambient light input, is fairly significant. As an incidental note, this particular "technology" is very popular with the "plastic semiconductor" people who claim – within only a few decades – to be able to produce flexible PV elements that you can rip and tear to fit your own roof.

A significant area of development recently also attacks the problem of the "frequeny band" limitation. Most commercially available PV semiconductors work primarily with light in the visible spectrum. It is very difficult to modify the "best frequency" for a given device, since the "energy gaps" are an inherent property of the semiconductor used. By using semiconductors other than Silicon, a few PV devices that work with InfraRed inputs have been produced. With these devices, you don't need a clear sunny day to get power, as long as the air is warm in the vicinity of the device. Thus far, peak power densities are somewhat lower than for "visible light" PVs, but the longer daily working cycle appears capable of more than compensating. This kind of "different" cells are commercially available now in limited quantities, but could be fairly widely available within a fairly short time.

Faskinating Stuffs going on. Still marginal on a $/watthour basis, for most people, but there are a lot of people working on it.

John

Subject: RE: BS: Solar Power big improvement at last
From: Keef
Date: 20 Mar 06 - 06:20 AM

Hi John (and others wot is interested)
I'm not here to plug any particular product, but if you have a look at the Sunball website I believe most of the likely issues have been taken into account.
The fact that something similar was tried in the eighties is not terribly relevant, price of the electronics and servos to perform the tracking is now way cheaper and the solar cells used are very high efficiency
Quote...
"The SunCube Solar Appliance uses 32 - 37% efficiency triple junction solar cells normally only used in space. Close cousins of our solar cells power the two Mars rovers Opportunity and Spirit. Flat panels solar cells normally rate around 15%."
Cost of batteries is prohibitive unless you are off grid and there is no other alternative. Grid connected solar such as the Sunball can provide very useful energy contribution and will obviously give the most output on sunny days at the same time that all those dreadful air conditioners are turned on!
(Many houses have appalling design with no overhanging eaves and huge windows that are unliveable unless the airconditioner is running)
Once again I stress that I have no connection with this company but I am impressed with the fact that it is a good Aussie invention (Yeah) and that it does appear to give much more bang for the buck than anything else on the market.
And yes I am intending to buy one, if this had been on the market when I was starting construction on my new house 2 years ago then I would definately have gone solar power. I do have solar hot water and a well designed passive solar house that requires no heating or cooling.