Cheaper solar: This solar concentrator uses mirrors and lenses to focus light, reducing the amount of semiconductor material needed and cutting costs. The rectangular module is mounted with the same hardware as conventional flat solar panels.
Soliant Energy, Inc. Patent Pending
A new roof-mounted system that concentrates sunlight could cut the price of photovoltaics.
A new mechanism for focusing light on small areas of photovoltaic material could make solar power in residential and commercial applications cheaper than electricity from the grid in most markets in the next few years. Initial systems, which can be made at half the cost of conventional solar panels, are set to start shipping later this year, says Brad Hines, CTO and founder of Soliant Energy, a startup based in Pasadena, CA, that has developed the new modules.
Concentrating sunlight with mirrors or lenses on a small area cuts the costs of solar power in part by reducing the amount of expensive photovoltaic material needed. But while concentrated solar photovoltaic systems are attractive for large-scale, ground-based solar farms for utilities, conventional designs are difficult to mount on rooftops, where most residential and commercial customers have space for solar panels. The systems are typically large and heavy, and they're mounted on posts so that they can move to track the sun, which makes them more vulnerable to gusts of wind than ordinary flat solar panels are.
Soliant has designed a solar concentrator that tracks the sun throughout the day but is lighter and not pole-mounted. The system fits in a rectangular frame and is mounted to the roof with the same hardware that's used for conventional flat solar panels. Yet the devices will likely cost half as much as a conventional solar panel, says Hines. A second-generation design, which concentrates light more and uses better photovoltaics, could cost a quarter as much. He says that a more advanced design should be ready by 2010.
The Soliant design combines both lenses and mirrors to create a more compact system. Each module is made of rows of aluminum troughs, each about the width and depth of a gutter. These troughs are mounted inside a rectangular frame and can tilt in unison from side to side to follow the sun. Each trough is enclosed on top with a clear acrylic lid. Inside each trough, a strip of silicon photovoltaic material runs along the bottom. As light enters, some of it reflects off the inside surface of the trough and reaches the strip of silicon. The rest of the incoming light is focused on the strip by a lens incorporated into the acrylic lid.
As a solar concentrating system, this design has a few drawbacks. Because the troughs are mounted close together, they shade each other during parts of the day, decreasing the total amount of electricity produced. They can also only track from side to side, which makes it impossible for them to follow exactly the arc of the sun across the sky. This second problem will be addressed in the second-generation design, in which each trough will be divided into sections, each of which can pivot from side to side and also up and down.
Skyline Solar, a new startup, is combining conventional technologies to lower solar-power costs.
A more efficient way to concentrate sunlight could reduce the cost of producing solar power.
An issue may be with the heat generated by the panel to the roof. How is that handled in this situation?
Why not consider doing something with the waste heat, like heating water. Solar cogeneration is seldom considered. I wonder why not.
That is a great idea. How long before we see integrated water heating and photovoltaic systems? You could image a system that handles the infrared separately from the other spectra. Using each part of the spectrum to its fullest advantage and reducing "waste heat".
Thanks. I'm sure it would boost overall efficiency somewhat. Cogenerators using gasoline engines are old hat but why those tricks aren't being used with photovotaics and hot water systems in the home are beyond me. Gasoline powered cogenerators burn gas, generate electricity, and use the hot water from the engine block to warm a building. The overall efficiencies can be very high.
First the infrared heat and UV heat is block (56%) with a polymer substance, same as found in the new windows films. Then the rest of the heat is dissipated with heat sinks. There are several companies that have solved this problem and are waiting for funds to going into the production phase. We will most likely no see any products until the completion of the Bush administration.
Solar cogen great idea, but water a bear
Solar PV cogeneration sounds like a great idea.
Intense concentrators, like www.greenandgoldenergy.com.au's 500:1 fresnel lens system, absolutely have to have a method to dissipate that tremendous thermal load, otherwise the silicon PV "melts". Essentially, they're deliberately using the aluminum structure as a heat sink to disipate that heat.
Using water sounds great.
But water always has the potential leakage issue.
A bigger deal because of the proximity of electrical devices.
Worse yet, at these heat / potential temperature levels, there is the danger of a steam explosion.
An all too real and really seriously bad thing.
Probably have to have a wicked good safety system.
Or some sort of elegant / cool totally failsafe passive intermediary heat transfer system.
HI,
There are several German companies who combine the 2 technologies in a very interesting way. I don't remember the name but I have seen several installation of this type here in south of France where I live.
Best regards,
/Farhad
In addition to the plumbing issues, there is the problem that silicon solar cells are much less efficient when they get hot. By the time you allow them to run at temperatures high enough to provide useful water heat, the electricity output has been seriously impacted (realize that the cells will run substantially hotter than the temperature of the "cooling" water).
If you really need hot water, the tradeoff may be worthwhile. But in many cases, it may be actually be more cost effective to install separate PV and solar hot water systems.
There's a story on just this in the recent edition of "Alternative Energy Retailer."
Check out the webpage http://www.aer-online.com/splash.phtml
It's a paper magazine, and I don't know if you'll actually be able to get this particular article anymore, but it's free, and if you're into this stuff might be worth getting.
There is no need to heat water to a very high temperature. In fact, it would be possible to heat the water to a lower temperature to that required, and then complete the heating using a conventional method. One key issue is achieving the required rate of heat transfer with the solar cells running at as low a temperature as possible. Of course the rate of heat transfer is direcly dependent on the temperature difference of the source.
unless a roof is mirrored it will be heated by the sun anyway, but all the heat will be wasted. this diverts a little of that energy into electricity.
so the roof will actually stay a bit cooler.
How about all the heat that is generated by appliances in the house (ie: Refrigerator, oven, etc...we have to find a way to capture that energy as well)
I'm glad that you're looking for novel ways to produce energy. However, the two appliances you mentioned (a refrigerator and an oven) probably could not be used to harvest energy and efficiently produce electricity.
The purpose of a refrigerator is to remove heat from an interior chamber. If you try to attach something to the hot area at the back of the fridge (for producing electricity), that would increase the thermal resistance and make it harder for the fridge to do its job of getting rid of heat from the inside compartment. The fridge would have to consume additional electricity, more than you would be able to produce.
As for the oven, it is possible to use it to generate electricity, but since you want the appliance to reach and maintain a nice high temperature (for cooking your food), I think the best choice would be to get an oven which is more insulated. That way, the oven would be losing heat (to the kitchen environment) more slowly, and it would require less energy to maintain the high temperature and cook your food. IF, after you finish cooking, you could attach some system which would cool your oven and produce electricity in the process, that might be worthwhile, but I think that the cost of such a system would be much higher than the value of the small amount of electricity it could produce.
Summary: Don't use your household appliances to make electricity. Buy more efficient appliances.
One can combine the generic solar water heater with the PV concentrator system to get both the technical and the cost synergies. This basically mean sandwiching the PV system into the hot water panel, twixt the transparent glass/acrylic cover and the water plumbing. Wherein the heat transfer medium is ordinary car water+antifreeze mix.
As it circulates this mix cools the PV cells and transfers the solar heat into the heat sink being the in-house hotwater tank, via a heat exchanger.
This then implies the auto industry absorbing the solar sector. After all in the manufacturing context the generic solar hotwater systems are the assembly of the car's windscreen, radiator, plumbing and related components. Which is why Toyota and Fiat are the biggest manufacturers of solar hot water heaters in Japan and Italy respectively.
For them to incorporate the PV panels is the logical next step.
Wouldn't the same sunlight hit the roof anyway The solar panel would not generate any heat of its own
There are moving parts in this, they say long life, but I wonder what that life is, and if replacements parts are something that will be available when you need them.
Still, even with that, this is a fantastic development. I hope when they say it's comparable with grid, they mean without subsidies.
What is the energy return on investment? I have heard conflicting things about PV ranging from the just break even on EROI over their life time to they break even in a fraction of their life time.
Why is there a big deal about EROI?
No one asks about EROI when they buy an automobile, truck, flat screen television, surround sound system.
The solar system adds value to the property it is being installed on so that has be an incentive to purchase the unit.
Firstly, the energy return on investment is absolutely fundamental to the role of solar energy in the energy economy. If it isn't positive, the devices do not improve sustainability at all.
Secondly, modern photovoltaics do have a positive EROI, but it does take a long time to break even.
How resistant is it to hail? Have to think about that, especially since I live in the MidWest.
see the website http://www.greenandgoldenergy.com.au/
for a similar australian invention (the suncube)
website contains
a detailed discussion of the issues and economics
The www.greenandgoldenergy.com.au product, a 500:1 fresnel lens 2-axis concentrator 3J (triple junction) system is currently commercially available.
A post mounted system, versus this "flat" "roof" system.
An obvious potential competitor to this system.
It is quite likely that immprovements in solar concentrators will occur as the cost of controllers (Moore's Law) and small motors decline and solar designers incorporate these improvements into solar systems.
We invented a system several years ago that accomplished the same idea without the need of the Acrylic lenses. Our system would track automatically, too. We should talk soon.
Charles G. Nutter, CEO Silacon.com
Guest (rhapsodyinglue)
It seems with this type of flat panel, even with the second generation able to pivot on two axis, it would need to be on a south facing pitched roof to track closely and get the most advantage from the concentrating. Due to that and the loss of efficiency in indirect sunlight, I wonder if this really would pay off in most/many situations.
If I were to consider putting one of these on my roof, it certainly doesn't seem easy to figure out what the real average output would be over a year.
Best companies SolFocus and EnergyInnovations
The best companies in this space are SolFocus which has a thiner safer cheaper concentrator with fewer moving parts.
http://solfocus.com/technology.html
And Energy Innovations which has the SunFlower that fulfills the dreams of an earlier poster about using heat energy in a heat engine as well as visible energy in a PV cell.
http://www.energyinnovations.com/sunflower.html
Guest (slapstick)
Re: Best companies SolFocus and EnergyInnovations
The sunflower? Not only was that bulky and completely impractical, it was just plain old ugly.
I hear EI is coming out with a new design, but if its anything like the sunflower it has about zero chance of succeeding. Solfocus has some promise, I think they are still a lot further from commercial production though. We'll see.
Re: Best companies SolFocus and EnergyInnovations
Good points. Also, be aware that the SolFocus product has more moving parts than they let on. Above a factor of few in concentration, there's no way around the basic need to track, no matter how small or clever the optics are.
That said, the two products (SolFocus and Soliant) really serve different markets. The Soliant product targets flat roofs, whereas the SolFocus product targets applications where a pole mount is acceptable.
I am not as familiar with solar cells as most of you, however, if the photo-voltaic cells can be made as a rod or tube and that is placed down the center of a collecting/reflecting trough, it seems to me that tracking becomes a non-issue. Then you only need to adjust the angle of the panel to maintain the 90 degree angle for maximum exposure. Is that so?
I believe you are essentially correct; this is basically the approach taken by large solar thermal trough collectors installed in California. (Why isn't there more interest/discussion about thermo-electric generation?) However, your surface/cell multiplier is not squared, but linear, so you need more Expensive(!) PV cell area. (You also lose that small percent at the ends of the troughs, but let's assume the troughs are long enough to neglect this effect.)
Sometimes I am simply amazed at the answers right in front of our face. So by concentrating the sun's photons on a smaller panel we are able to conduct for energy with much less space. That's awesome reminds me of frying ants with a magnifying glass
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nekote
139 Comments
Total $ / net KWH
Total $ / net KWH
Always the key question.
The delivered price of the energy.
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Higon Lee
3 Comments
Re: Total $ / net KWH
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Higon Lee
3 Comments
Re: Total $ / net KWH
Dear Sir,
I want to know the price of module.
Thanks,
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nov.1118
1 Comment
Re: Total $ / net KWH
i am seeking info on advances in solar technology&price info on panals, installation costs,and all materials. Potential KWH/#panals,and time savings will equal installation costs estimate.
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minkram
1 Comment
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no comm.
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