Torben V. Mogensen wrote:
....
> Hej Glenn
>
> Tak for dit link. Jeg er godt klar over at der også er meget varme i
> lyset, og målte også 160 grader på solcellen under mit forsøg. (det kunne
> den ikke lide) Og virkningsgraden falder i takt med at den bliver
> varmere, det er ærgeligt synes jeg. Det ville være godt hvis
virkningsgrad
> var den samme, selvom den bliver varm.
> Altså hvis vi sender 1000 W ind på den og den giver 12 % strøm.
> Og så hvis den også kunne give 12 % strøm ved 3000 W ind på den.
Men der
> viste mit forsøg at den måske så kun giver 2-3 % strøm ved 3000 W.
>
> På dit link, er det så mon en speciel solcelle i materialer, eller
bare en
> alm solceller der bliver meget kølet med kølevand?
Jeg formoder at det er almindelige solceller - men med god kobling til
køling - og ledningsbaner, der kan klare højere strømme.
>
> Hvad står N for i NIR?
Kig på:
http://da.wikipedia.org/w/index.php?title=Infrar%F8d_str%E5ling
>
> Den elektromotoriske kraft over en solcelle falder med stigende
temperatur.
> Hvad er det som ikke kan følge med, hvilket materiale bliver sløvere, for
> meget andet i fysik/kemi så reagerer stoffer hurtigere ved stigende
temp.?
> Men ikke lige i solceller.
Halvledere (og plasma) har den umiddelbart ikke-intuitive egenskab, at
deres modstand falder med temperaturen. Småforurenede halvlederepletter
N, P får også lavere modstand med temperaturen:
http://da.wikipedia.org/wiki/Halvleder
Dioder og transistorer får større lækstrømme med temperaturen.
> Er der en bestemt frekvens som er gunstig for solceller til at lave
strøm?
Ja, det er der faktisk - solceller er snæversynede. De "almindelige"
solceller giver størst virkningsgrad ved NIR (Mit gæt: omkring 800 nm
....1000 nm). Ved lavede bølgelængder bliver overskuddet lavet om til
varme. Løsningen er måske her:
25 July 2002, Photons double up for solar power.
Solar cells could get an efficiency boost of 30% using a device proposed
by physicists in Australia and Germany. Martin Green of the Centre for
Third Generation Photovoltaics at the University of New South Wales and
colleagues say that 'down-converters' could be connected to existing
solar cells to double the number of 'useful' photons they capture (T
Trupke et al 2002 J. Appl. Phys. 92 1668).
Citat: "... But the most promising arrangement would see the
down-converter connected to the 'front' of a solar cell. Although this
would block out low-energy photons, it would still boost the overall
efficiency of the cell to 38.6%. Most importantly, say the researchers,
this set-up would allow existing semiconductor solar cells to be fitted
with down-converters.
http://physicsweb.org/articles/news/6/7/19/1
According to Green and colleagues, the down-converters should be simple
to make from materials such as aluminium arsenide or gallium phosphide,
using established 'epitaxial' manufacturing techniques. ..."
7 December 2001 Solar cell edges towards endless energy
http://physicsweb.org/articles/news/5/12/2
-
Her er "solceller" - faktisk "termiske varmeceller"?:
Har de mon fået den masseproduceret?:
Device could aid production of electricity
November 27, 2001
http://web.mit.edu/newsoffice/2001/electricitydevice.html
November 27, 2001
Utah Company Improves Process to Convert Heat Into Electricity
http://www.eneco-usa.com/news/improves.htm
ENECO UNVEILS NEW ENERGY TECHNOLOGY
Jan 1, 2002 12:00 PM
http://ceenews.com/mag/electric_eneco_unveils_new/
thermionics converter
Microchip can turn heat into electricity
http://www.newscientist.com/hottopics/tech/article.jsp?id=99991862&sub=Nanotechnology
"...
By placing an additional highly doped electron-rich layer between the
emitter and collector, the team got more electrons to traverse the gap,
though they are not quite sure how yet. "The details of the mechanism
are still under discussion," says Hagelstein.
They speculate that high-energy electrons reaching the electron-rich
layer cause a scattering "chain reaction" whose overall effect is to
turn more of the heat into current.
...."
Material boosts thermoelectricity
http://www.trnmag.com/Stories/2004/040704/Material_boosts_thermoelectricity_Brief_040704.html
-
Men husk at det der bedst betaler sig er solceller som kan give mest
energi/kr i hele deres levetid. Også i overskyet vejr, som vi har en del
af i Danmark i løbet af året.
Her er lidt til solcellestyring:
The Zener-based solar engine
Using a Zener diode as a voltage sensor
http://www.solarbotics.net/library/circuits/se_t1_zener.html
SCC3 - 12 Volt 20 Amp Solar Charge Controller Kit
http://www.solorb.com/elect/solarcirc/scc3/
http://www.cirkits.com/scc3/
http://www.cirkits.com/scc3/scc3specs.html
SCC2 10 Amp Solar Charge Controller
http://www.solorb.com/elect/solarcirc/scc2/index.html
-
Bemærk at hvis man vil anvende bly-akkumulatorer så se deres
begrænsninger her:
BATTERY INFORMATION LINKS LIST
http://www.uuhome.de/william.darden/batlinks.htm
Car and Deep Cycle Battery Frequently Asked Questions (FAQ) 5.1
http://www.uuhome.de/william.darden/index.htm
-
En bedre energi gemmemetode er her:
http://da.wikipedia.org/wiki/Svinghjul
F.eks.:
2003-11-14, Science Daily: University Of Texas At Austin Flywheel Spins
To A Milestone Speed Record:
http://www.sciencedaily.com/releases/2003/11/031114071848.htm
Citat: "...charged and discharged a flywheel 110,000 times with no
change in performance...it wastes less than 5-10 percent of the energy
stored as it is charged and discharged..."
RPM's No-Loss Power Storage/Regeneration System:
http://home.earthlink.net/~fradella/homepage.htm
RPM's Power Storage/Regeneration:
http://rpm2.8k.com/
Hvem har mon en opskrift på hvordan svinghjulslagre laves på køkkenbordet?
>
> MVH
>
> Torben
Kig på disse adresser:
2004-08-26, Sciencedaily: Vast New Energy Source Almost Here: Solar
Hydrogen Fuel Dream Will Soon Be A Reality, Australian Scientists Predict:
http://www.sciencedaily.com/releases/2004/08/040825094820.htm
Citat: "...
Using special titanium oxide ceramics that harvest sunlight and split
water to produce hydrogen fuel, the researchers say it will then be a
simple engineering exercise to make an energy-harvesting device with no
moving parts and emitting no greenhouse gases or pollutants.
It would be the cheapest, cleanest and most abundant energy source ever
developed: the main by-products would be oxygen and water.
....
"Based on our research results, we know we are on the right track and
with the right support we now estimate that we can deliver a new
material within seven years," says Nowotny.
....
Solar hydrogen, Professor Sorrell argues, is not incompatible with coal.
It can be used to produce solar methanol, which produces less carbon
dioxide than conventional methods. "As a mid-term energy carrier it has
a lot to say for it," he says.
...."
-
Solcelle revolution lige om hjørnet? Vurder selv:
Wladek Walukiewicz, Materials Sciences Division, Berkeley Lab.: Full
Solar Spectrum Photovoltaic Materials Identified.
A team led by Wladek Walukiewicz, working with researchers at Cornell
University, and Ritsumeikan University, Japan, has discovered that,
contrary to earlier reports, the band gaps of the In1-xGaxN ternary
alloy system extend over a very wide energy range (0.7 eV to 3.4 eV) and
thus provide a near-perfect match to the solar energy spectrum. This
creates the opportunity to design and fabricate new multijunction solar
cells that will have greatly improved efficiencies, possibly reaching
the theoretically predicted ultimate efficiencies.
http://www.lbl.gov/msd/PIs/Walukiewicz/02/02_8_Full_Solar_Spectrum.html
Citat: "... Maximum, theoretically predicted efficiencies increase to
50%, 56%, and 72% for stacks of 2, 3, and 36 junctions with
appropriately optimized energy gaps, respectively...."
22 November 2002, Semiconductor lights up solar cells.
....indium nitride... The result means that alloys containing the two
elements could be used to improve the efficiencies of solar cells...:
http://physicsweb.org/article/news/6/11/14
08 December 02, Solar cells aiming for full spectrum efficiency
http://www.newscientist.com/news/news.jsp?id=ns99993145
Citat: "... It should allow solar cells to jump in efficiency from
today's best of 30 per cent to 50 per cent or higher.... By varying the
ratio of indium to gallium in different layers, they were able to tune
InGaN's bandgap to match the criteria exactly. And because the range of
the bandgap matches the solar spectrum so perfectly, a cell could use
multiple layers tuned to bandgaps across the range to squeeze out even
more energy...."
November 20, 2002, Material Discovered For Full Spectrum Photovoltaic Cell:
http://www.futurepundit.com/archives/000668.html#000668
Citat: "... A new discovery raises the prospect of a more efficient
photovoltaic cell for lower cost solar energy. Two layers of indium
gallium nitride in a solar cell design could convert sunlight to
electricity at 50% efficiency.
....
"It's as if nature designed this material on purpose to match the solar
spectrum," says MSD's Wladek Walukiewicz, who led the collaborators in
making the discovery.
What began as a basic research question points to a potential practical
application of great value. For if solar cells can be made with this
alloy, they promise to be rugged, relatively inexpensive -- and the most
efficient ever created.
....
Furthermore, the discovery extends the range of potential optoelectronic
applications of III-V nitride alloys from the near infrared to the deep
ultraviolet spectral regions...."
25 November 2002, Bandgap of indium nitride measured as 0.7 eV.
New measurements indicating that the bandgap of indium nitride is 0.7
eV, rather than 2.0 eV, could open up new possibilities for
high-efficiency solar cells.
http://www.compoundsemiconductor.net/articles/news/6/11/17/1
Citat: "... The bandgap range of InGaN from 0.7 to 3.4 eV provides a
very close match to the solar spectrum..."
20 December 2002, Comments on "Bandgap of InN is 0.7 eV" story:
http://www.compoundsemiconductor.net/articles/news/6/12/17/1
-
March 29, 2002, Scientists Create New Solar Cell:
http://www.sciam.com/article.cfm?chanID=sa003&articleID=0004C094-02CC-1CD0-B4A8809EC588EEDF
Citat: "...semiconducting plastic material known as P3HT... 1.7 percent
for sunlight..."
15 February 03, 'Denim' solar panels to clothe future buildings:
http://www.newscientist.com/news/news.jsp?id=ns99993380
Citat: "... Unlike conventional solar cells, the new, cheap material has
no rigid silicon base... The bumpy surface presented by the spheres
offers a large area for absorbing light, giving the material an overall
efficiency of 11 per cent...."
-
Måske kan dette også bidrage til at designe mere effektive solceller:
20 December 2002, CdSe quantum dots boost organic LEDs:
Researchers have produced an organic LED that is about 25 times more
efficient than the best quantum-dot LEDs to date.
http://www.compoundsemiconductor.net/articles/news/6/12/18/1
Citat: "... Another advantage of this type of LED, say the team, is that
every electron-hole recombination can produce a photon -- leading to a
possible 100% quantum efficiency at any visible wavelength. In many
materials quantum statistics limit the efficiency to 25%...."
-
"PhotoElectroChromic" eller "PEC solar" information:
12 February 2003, Dyes provide solar cell alternative.
Researchers develop a device that could be a low-cost alternative to
silicon-based solar cells.
http://optics.org/articles/news/9/2/9/1
Citat: "... The main advantage of the method is that an unusually large
number of the photons absorbed by the dye layer - about 10% - generate
electric current..."
18. juni 2002 Indland Vinduer kan producere strøm:
http://www1.dr.dk/nyheder/indland/article.jhtml?articleID=59293
http://www.solenergi.dk/solceller_pec.asp
NewScientist.com news service, 7 August 03, Most efficient solar cell
yet revealed:
http://www.newscientist.com/news/news.jsp?id=ns99994033
Citat: "...Spectrolab, a subsidiary of Boeing based in California, US,
has created a photovoltaic cell capable of converting 36 per cent of the
Sun's rays into electricity...."There is still room for improvement."..."
Solceller - formod. 50% effektivt. Zink, mangan, tellurium og oxygen
baseret:
http://cph.ing.dk/konf/root/hvemhlp/html/5776.all.html#12641
November 10, 2003, Scientific American: Novel Semiconductor Could Soup
Up Solar Cells:
http://www.sciam.com/article.cfm?chanID=sa003&articleID=000C80EF-20D6-1FAC-A0D683414B7F0000
Citat: "... could form the basis of solar cells with nearly 50 percent
efficiency....Kin Yu of Lawrence Berkeley National Laboratory and
colleagues investigated the properties of a new semiconductor material
comprising an alloy of zinc, manganese and tellurium... added oxygen
impurities..."
08 December 02, Solar cells aiming for full spectrum efficiency:
http://www.newscientist.com/news/news.jsp?id=ns99993145
Citat: "... It should allow solar cells to jump in efficiency from
today's best of 30 per cent to 50 per cent or higher.... By varying the
ratio of indium to gallium in different layers, they were able to tune
InGaN's bandgap to match the criteria exactly. And because the range of
the bandgap matches the solar spectrum so perfectly, a cell could use
multiple layers tuned to bandgaps across the range to squeeze out even
more energy...."
mvh/Glenn