In dem oben erwähnten Forum "ENTECH SOLAR - DER NEUBEGINN" war
zuletzt das Thema "Fresnel Kollektoren" als kostengünstige(re)
Alternative zu "Parabolrinnen" näher beleuchtet worden.
Hier noch ein paar Ergänzungen zum Begriff "Fresnel refractors"
Auszug von S. 15 der folgenden "Texas Roadmap":
http://www.citizen.org/documents/TexasSolarRoadmap.pdf
Entech Solar, Inc., a Fort Worth based company, uses crystalline
solar cells in its concentrating PV systems, which it has been
designing and installing for the last 25 years. Entech’s suite of
products produce only electricity, electricity and heat, or heat
only. Entech has completed the build out of a new 71,000 square
foot facility and is now finishing up a production line that will
produce 50 MW per year of concentrating PV. Entech’s PV terrestrial
products use mono-crystalline solar cells under
Fresnel lens at 20 suns concentration. Entech uses high-efficiency
multi-junction solar cells under its Fresnel lens in the Company’s
space solar systems for NASA and U.S. DOD.
Crossing Boundaries: Concentrating PV
The mirrors used in CSP plants to focus and capture the sun’s heat
can also be used to focus sunlight on photovoltaic modules –
reducing the amount of silicon needed for PV systems.
Entech
Solar, a Fort Worth-based company, has developed technology that
focuses sunlight on a string of photovoltaic solar cells using
Fresnel refractors.
Und dann noch die einleitenden Ausführungen zum SLA-Projekt:
http://www.stretchedlensarray.com/TheProject.htm
Background
For several years now, NASA and ENTECH have been developing and
refining space-qualified photovoltaic solar arrays that use a
refractor concentrator technology. There are advantages to
using refractive concentrators instead of reflective concentrators
(this will be discussed later). Back in the early 1990's, the first
refractive concentrator array was flown on the PASP Plus
(Photovoltaic Array Space Power Plus Diagnostics) space mission.
The array was composed of ENTECH's "mini-dome" focusing lenses over
Boeing's mechanically stacked multi-junction solar cells. The
lenses were a point-focus design and were coated to provide
protection against the ultraviolet radiation (UV) and atomic oxygen
(AO) that is found in space. It was one of a number of small,
advanced arrays and it performed very well in a year-long mission
that was in a very high radiation environment. It validated both
the high performance and radiation hardness of the refractive
concentrator approach.
Indeed, SLA is unique among all solar array technologies in its
portfolio of attributes, which include world-record-level
solar-to-electric conversion efficiency (high W/m2), ultra-light
mass density (low kg/m2), spectacular stowed power density (kW/m3),
highly scalable power (kW to multi-MW), high-voltage capability
(kV), modularity (individual lens/cell building blocks),
mass-producibility, and cost effectiveness. SLA’s unique portfolio
of attributes matches the critical requirements for space power
systems for many of planned NASA’s Exploration missions.
P.S.
Allen Zweiflern zum Trotz - die Weltraumforschung wird ihre Früchte
auch für "terrestrische" Anwendungen tragen - so wie es bereits in
2005 in dem folgenden Report zur ICSC2005 dargelegt worden
ist...
http://www.stretchedlensarray.com/Papers/ICSC2005.pdf
ENTECH's Stretched Lens Array (SLA) for NASA's Moon/Mars
Exploration Missions,
Including Near-Term Terrestrial
Spin-Offs
Mark J. O’Neill
ENTECH, Inc.
1077 Chisolm Trail
Keller, TX 76248 USA
Zitat ( Auszug ):
More recent SLA mini-concentrator modules have
routinely been measured by ENTECH at over 30% net
operational efficiency in outdoor tests under a wide range of
conditions [14]. These spectacular SLA efficiency values
are essentially twice the efficiency values of ENTECH’s
previous terrestrial concentrator systems, which employed
mass-produced silicon cells. Because of this enormous
efficiency leverage, ENTECH has been performing
development for the past five years, aimed at adapting the
core elements of SLA space technology to terrestrial solar
power. The two core technology elements are ENTECH’s
patented color-mixing Fresnel lens, and multi-junction
concentrator cells made by Spectrolab, EMCORE, and
others. In space, array mass is a key driver. On the ground,
energy cost is the key driver. Thus, a higher concentration
ratio (to minimize cell area and cost) will be needed for the
terrestrial version, implying a point-focus color-mixing lens
in place of the line-focus color-mixing lens used in space.
While the details of ENTECH’s spin-off plans remain
proprietary, the terrestrial module is expected to resemble
the mini-dome lens module shown in Fig. 13. Since higher
concentration generally implies higher efficiency (with
proper cell and thermal design), future terrestrial systems
should be even more efficient than the 30% miniconcentrator
modules discussed above
Und dann gibt Mark J. O'Neill auf einer im November 2009 in Hamburg
stattfindenden Experten-Konferenz den folgenden Statusbericht
ab:
http://www.photovoltaic-conference.com/fileadmin/template/re…
http://www.photovoltaic-conference.com/search.0.html?&L=0&L=…
Tuesday, 22 September 2009
ORAL PRESENTATIONS 1BO.5
10:30-12:00 Space and Concentrator PV Technology
1BO.5.1 R. Campesato, M. Casale, G. Gori, G. Gabetta & C.
Flores
CESI RICERCA, Milan, Italy
M. Kagan & V. Semenov
OJSC RPE "KVANT", Moscow, Russian Federation
Triple Junction Solar Cells and Solar Panels for the New Generation
of Russian Spacecraft
1BO.5.2 H.W. Brandhorst Jr., J.A. Rodiek & S.R. Best
University of Auburn, United States
M.J. O'Neill
ENTECH, Fort Worth, United States
M.F. Piszczor
NASA Glenn Research Center, Cleveland, United States
High-Voltage Multi-Junction-Cell Concentrator Array Direct-Driving
an Electric Thruster Test Results