[lifesaviors] Electro-Magnetic Casting: EMC, high volume lowest energy PV solution
- From: <lionkuntz@xxxxxxxxx>
- To: TheEnvironmentalMovement@xxxxxxxxxxxxxxx,wastewatts@xxxxxxxxxxxxxxx
- Date: Mon, 15 Sep 2003 15:08:44 -0700 (PDT)
The following information includes Solar PV Breeder
webpage links, and exerpts from same links.
Electromagnetic casting generates silicon PV ingots at
the lowest enrgy costs and fastest rates of all
systems known today. The original patent expires in
three years. Licencing of use of the patent can allow
sooner use. The EMC process is the heart of the
proposed "Solar PV Breeders" technology providing the
low-cost solar panels needed for Palaces For The
People power systems autonomy. Palace PV breeders will
grow PV wafers and thereby earn the payoff of the cost
of their initial solar power equipment in the first
year of operation. Further years provide an income
stream to the Palace as additional Palaces are
equipped at a rate of one per year.
http://www.nrel.gov/silicon/EMC.htm
Electromagnetic Casting
We discovered and patented the semicontinuous
electromagnetic cold-crucible casting technique for
silicon in the mid-1980s (Theodore F. Ciszek, "Method
and Apparatus for Casting Conductive and
Semiconductive Materials," U.S. Patent 4,572,812,
1986. This method has a higher throughput than any
other Si ingot technology, because of the easy heat
transfer to a cold environment. A trade-off is that
grain size is small because of the rapid cooling.
However, the purity level is very high because this is
essentially a "containerless" method. All things
considered, the method makes >13%-efficient production
cell efficiencies at a high throughput. While it has
not caught on in the US, it has been more vigorously
developed in Europe and Japan, where ingots weighing
over 190 kg with cross sections of 22 x 22 cm are
produced.
http://www.nrel.gov/silicon/Nmulticrs.htm
Electromagnetic casting (EMC), shown here, has some
similarities to the casting and DS methods just
described, but also has several unique features that
change the ingot properties and warrant a separate
discussion. The method was first applied to
semicontinuous silicon ingot casting by Ciszek (1985,
1986). EMC is based on induction-heated cold-crucible
melt confinement, except that unlike the conventional
cold crucible, there is no crucible bottom. A
parallel, vertical array of close-spaced, but not
touching, water-cooled, conducting fingers is attached
at one end to a water-cooling manifold. The other end
of each finger is closed. An internal distribution
system carries cooling water to the tip and back
again. The shape of the region enclosed by the
close-spaced fingers determines the cross section of
the cast ingot, and a wide variety of shapes are
possible (circular, hexagonal, square, rectangular,
etc.). Silicon is melted on a vertically moveable
platform (typically graphite) located within the
finger array. The melting is accomplished by
induction heating after suitable preheating. The
induction coil, placed outside the finger array,
induces a current to flow on the periphery of each
finger, around the finger's vertical axis. Like a
high-frequency transformer, each finger in turn
induces a current to flow in the periphery of the
silicon charge, about its vertical axis. The silicon
is heated by its resistance to the current flow.
There is Biot and Savart-law repulsion between the
current flowing in the periphery of the silicon melt
and the currents flowing in the fingers, because they
are induced to flow in opposite directions at any
particular instant in the RF cycle. Thus, the melt is
repulsed from the water-cooled fingers. The
open-bottom arrangement allows the platform to be
withdrawn downward, solidifying the molten silicon,
while new melt is formed by introducing feed material
from the top. In this way, a semicontinuous casting
process can be carried out.
A variety of feed silicon geometries can be used
(melts, rods, pellets, scrap, etc.). Because the
interface is submerged, feed perturbances or slag at
the melt surface do not affect the solidification
front. Ingot lengths of 3 m have been demonstrated.
The cross section of the ingots has evolved over years
of development and is currently about 350 mm x 350 mm.
The cold fingers allow steep thermal gradients and
fast growth speeds (~1.5-2.0 mm/min), even in ingots
with large cross sections. But they also cause a
steeply curved interface that is concave toward the
melt. Thus, grains are neither as columnar nor as
large as in conventional DS. The average grain size
is on the order of 1.5 mm in large ingots. This
decreases t, but the relatively high purity and
freedom from oxygen and carbon impurities (O < 6x1015;
C < 8x1016) largely offset the grain-size effect, so
that solar cell efficiencies of about 14%-15% are
obtained on 15 cm x 15 cm cells. The throughput of
EMC is the highest of any ingot growth technique - up
to approximately 30 kg/h. The power consumption is
about 12 kWh/kg.
http://www.nrel.gov/silicon/Nfuture.htm
Future Trends in Silicon PV Materials Technology
... Multicrystalline casting, directional
solidification, and electromagnetic casting
are commanding an increasing share of the Si PV market
(53% of all ingot ...
www.nrel.gov/silicon/Nfuture.htm - 13k - Sep 14, 2003
http://www.nrel.gov/silicon/NCompGr.htm
Silicon Crystal Growth Methods - A Comparison
... For example, the highest throughput ingot method,
electromagnetic casting, yields
lower cell efficiencies than the slower CZ growth
method because of smaller ...
www.nrel.gov/silicon/NCompGr.htm - 56k - Sep 14, 2003
http://www.nrel.gov/silicon/industry.htm
Silicon Materials Research with Industry at NREL
... a "containerless" silicon feedstock particulate
consolidation system based on
our cold-crucible electromagnetic semicontinuous
casting process (Theodore F ...
www.nrel.gov/silicon/industry.htm - 10k - Sep 14, 2003
http://www.nrel.gov/docs/fy01osti/30280.pdf
PDF]Solar Electricity: The Power of Choice, Second
Quarter 2001
File Format: PDF/Adobe Acrobat
... There are also 140 patents, spanning materials
innovation (such as electromagnetic
Si casting, new transparent con- ducting oxides),
through devices (GaInP/GaAs ...
www.nrel.gov/docs/fy01osti/30280.pdf
http://www.chem.uu.nl/nws/www/publica/95057.htm
Summary 'Environmental life-cycle assessment of
multicrystalline ...
... conventional casting, electromagnetic casting, ...
Environmentally relevant substances
which may be released in multicrystalline silicon PV
module production are ...
www.chem.uu.nl/nws/www/publica/95057.htm
http://www.sumitomocorp.co.jp/o-hitetsu/emcsolar.htm
EMC SOLAR GRADE POLY CRYSTAL SILICON WAFER
... effective manufacturer of high quality polycrystal
silicon wafer for photovoltaic
(PV) industry. The method of wafer production is
Electromagnetic Casting (EMC ...
www.sumitomocorp.co.jp/o-hitetsu/emcsolar.htm - 9k
http://www.ecotopia.com/apollo2/pvepbtne.htm
Energy Pay-Back Time (EPBT) and CO2 mitigation
potential
... silicon process in combination with
electromagnetic casting of mc ... Because the (energy)
costs of silicon are virtually ... will improve only
when the PV market is ...
www.ecotopia.com/apollo2/pvepbtne.htm - 17k
=====
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Sincerely, Lion Kuntz
Santa Rosa, California, USA
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http://groups.yahoo.com/group/Palaces4People/
http://groups.yahoo.com/group/Palaces4Japan/
http://www.ecosyn.us/ecocity/Proposal/Palaces_For_The_People.html
http://www.ecosyn.us/ecocity/Challenges/Asia_Floods/Wet/All_Wet.html
http://www.ecosyn.us/Interesting/
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