I am working with the idea of building my own Concentrator with about 50 times the mirror space then collector space. That Is why the question was asked in the first place I was wondering if placeing a 50watt solar panel at the focal point would increase the power output. I've read that it is more then 100% liner increase in power output when increasing the amount of light on it. a normal panel at 50 watts would be 2500 watts at 50 suns. I know it would need to be kept cool. due to the fact that they are only 20-30% efficent, but I could use the coolant to heat my biodiesel processor, then the hot water going into my home before a tankless heater. If I were to get a grid tied inverter It would suppliment my normal power useage and maby with netmetering it might come close to canceling out my power requirements alltogther. a simple temp sensor could be used so if the temp is over 150f in the coolant it will shut down and not collect the sun anymore. As for a solar tracker that is relative easy with very simple electronics. The setup to hold everything would be a simple build for most people who can make their own biodiesel processor. And If I base it off a 7 meter dish I can get those free. I just have to use the labor to remove it.
Logan Vilas ----- Original Message ----- From: "Zeke Yewdall" <[EMAIL PROTECTED]> To: <Biofuel@sustainablelists.org> Sent: Friday, May 12, 2006 3:59 PM Subject: Re: [Biofuel] Solar Concentrator & PV Modules >I am speaking mostly from experience, from what I have seen work and > fail in the field, and what I can buy to install for my clients. The > reason I talk about trackers on large poles is because that is what is > commercially sold right now (at least in the US, europe is ahead of us > in many areas). And the biggest reason I see for failed systems is > lack of maintenance (mostly batteries, but also anything that moves). > Also, the number of new innovative PV systems that I have seen come on > the market over the years, only to dissapear within another year... > We're still basically doing the same thing as PV was in the 70's, with > incremental improvements in efficiency and incremental cost decreases. > I called the concrentrating PV exotic merely because I can't call up > one of 200 some suppliers and buy one that meets all current > electrical code, whereas I can with silicon PV modules. Maybe another > breakthrough is coming, but in the mean time, alot of people will keep > using coal generated power because they are waiting for those > breakthroughs. I would rather see working PV systems going in today, > even if they aren't all that high tech, rather than people thinking > they have to wait before solar energy can work for them -- and in the > mean time continuing to support coal and oil. It's not that I want > to limit the new technology, but what I have seen is that the > layperson holds out the possibility of a paradigm shift in the > technology in the future as a reason to do absolutely nothing now. > And if I recall, the original question was about concentrating > sunlight on a normal old PV module -- which isn't the best idea -- > they tried that at the carrizo solar plant in the early 80's, and a > few years later, a whole lot of used Mud-lams (because the encapsulant > turned varying shades of brown) flooded the market for off-grid use. > > I do admit that this list's members are not your average layperson, > and most of us won't just use the news of new inventions as an excuse > for procrastinating, so I apologize for that. > > Zeke > > > On 5/12/06, Michael Redler <[EMAIL PROTECTED]> wrote: >> >> By now, you may have noticed my resistance to "conventional wisdom" >> whenever >> someone gives negative feedback about a particular energy scheme. Here is >> an >> example. >> >> The idea of concentrating light onto PV cells is a relatively new idea in >> some circles. What to do about waste heat is a natural progression in the >> discussion of such technology. But, why is it seen as such an obstacle - >> especially when schemes for harvesting waste heat are so abundant in >> energy >> related discussions? >> >> You wrote: "...regular PV is cheap enough that the simplicity of not >> having >> >> moving parts will probably outweigh any advantage of trying to get more >> from >> the same amount of silicon." >> >> >> The sweeping statements are getting old Zeke. Adding trackers become >> advantageous when you run out of roof. By the way PV that works on >> concentrated sunlight isn't so exotic and will probably become the PV of >> choice in a large percentage of applications. The large cost of >> concentrating PV is likely to be offset by an increase in power >> conversion >> requiring the use of heliostats, tracking technology and those pesky >> moving >> parts. >> >> >> Mike >> >> Zeke Yewdall <[EMAIL PROTECTED]> wrote: >> >> Most of the highest efficiency PV cells do use concentrators. These >> are the 35% efficient super exotic ones that NREL and others are >> working on. Compared to 20% which is about the highest commercial >> single sun efficiency right now. In general the power produced by a >> PV cell is linearly related to the energy input. More sun = more >> power. So if you put 25 suns on it, you get 25 times the amount of >> power from the same cell (assuming you don't change the spectral >> composition of the l ight). It's not quite linear, so I think you >> actually get a tiny bit more power at higher concentrations than just >> the concentration ratio would imply -- say 28 instead of 25. The >> problem is that a typical crystalline silicon cell also decreased its >> power about 0.5% for each degree celsius the temperature goes up. So >> if you increase the operating temperature of the cell from 60C >> (typical for one sun) to 200C, you've just lost all the power you >> gained by putting more light on it.... Plus if you get too hot, >> you'll damage it -- usually the encapsulating material degrades well >> before the temperature at which the actual PV cell is damaged though. >> The other thing is that concentrators require tracking the sun usually >> (at least to achieve more than 2 or 3 times concentration. This >> introduces moving parts to the equation, and destroys one of the nice >> features of PV. If it's a big central power station where you can >> hire a full time maintenance operator, then go ahead. If for your own >> house, regular PV is cheap enough that the simplicity of not having >> moving parts will probably outweigh any advantage of trying to get >> more from the same amount of silicon. >> >> Zeke >> >> On 5/12/06, Joe Street wrote: >> > Actually mirrors can be used to concentrate the light from a large area >> > onto a small high efficiency solar cell. It is being done. This is one >> > of the justifications for the cost of high efficiency cells but the >> > extra cost of the concentrators and the lengths one has to go to to >> > keep >> > from overheating the PV module unfortunately outstrip the savings the >> > idea hopes to offer. Too bad but on the other hand if you are just >> > fortunate to have access to heterojunction cells on the cheap then >> > maybe >> > you should go for it! You will need a liquid cooled backing plate for >> > the cells but if you are crafty you might be able to use the rejected >> > heat somehow as well! >> > >> > Joe >> > >> > Lugano Wilson wrote: >> > >> > > hi Logan. >> > > >> > > PV modules and solar concentrators are two different technologies and >> > > unfortunately, their individual energy capture principle is >> > > contradicting to each other. consequently, they can not be used at >> > > same >> > > application. PV modules need to absorb all the solar radiation so as >> > > to >> > > generate electricity through the module cells where as solar >> > > concentrators have to reflect all the solar radiation and direct it >> > > at a >> > > specific location (ie concentrated) for the purpose of heating a >> > > medium >> > > that can latter generate required energy. you therefore need to >> > > choose >> > > one for a specific application. however, when it comes to electricity >> > > the pv modules are good due to the fact that you can size them >> > > depending >> > > on your requirement starting with one module and increasing. >> > > concentrators for electricity is a large scale project - not so >> "modular". >> > > >> > > Lugano >> > > >> > > */Logan Vilas /* wrote: >> > > >> > > Would a standard PV module produce more when used with a Solar >> > > Concentrator >> > > or does it require a special PV module? >> > > >> > > Logan Vilas >> >> [snip] >> _______________________________________________ >> Biofuel mailing list >> Biofuel@sustainablelists.org >> http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org >> >> Biofuel at Journey to Forever: >> http://journeytoforever.org/biofuel.html >> >> Search the combined Biofuel and Biofuels-biz list archives (50,000 >> messages): >> http://www.mail-archive.com/biofuel@sustainablelists.org/ >> >> >> >> > > _______________________________________________ > Biofuel mailing list > Biofuel@sustainablelists.org > http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Search the combined Biofuel and Biofuels-biz list archives (50,000 > messages): > http://www.mail-archive.com/biofuel@sustainablelists.org/ > > _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
