Annual Report 2006 - Plataforma Solar de Almería

FACILITIES AND INSTALLATIONS
nominal mean 90% reflectivity, the solar tracking error on each axis is
1.2 mrad and the reflected beam image quality is 3 mrad. The CESA-1 facility
has the most extensive experience in glass-metal heliostats in the world, with
first generation units manufactured by SENER and CASA as well as second
generation units with reflective facets by ASINEL and third generation facets
and prototypes developed by CIEMAT and SOLUCAR. In spite of its over 20
years of age, the heliostat field is in optimum working condition due to a strategic
program of continual mirror-facet replacement and drive mechanism
maintenance. To the north of the field are two additional areas used as test
platforms for new heliostat prototypes, one located 380 m from the tower and
the other 500 away from it. The maximum thermal power delivered by the
field onto the receiver aperture is 7 MW. At a typical design irradiance of
950 W/m 2 , a peak flux of 3.3 MW/m 2 is obtained. 99% of the power is focused
on a 4-m-diameter circle and 90% in a 2.8-m circle.
The 80-m-high concrete tower, which has a 100-ton load capacity, has
three test levels:
• A cavity adapted for use as a solar furnace for materials testing at
45 m, which has been used very successfully in reproducing the heat
ramp on space shuttles during their reentry into the atmosphere in
test pieces of the ceramic shield and also for surface treatment of
steels and other metal compounds.
• A cavity with a calorimetry test bed for pressurized volumetric receivers
at 60 m. At the present time this cavity houses the SOLGATE project
infrastructure, which includes three volumetric receivers with a total
incident power of nearly 1 MW, 250-kW solarized turbine, and corresponding
electric generator, air loop, heat rejection system and
thermal shield.
• The 2.5-MW TSA volumetric receiver test facility at the top of the
tower at 80 m.
The tower is complete with a 5-ton-capacity crane at the top and a freight
elevator that can handle up to 1000-kg loads. Finally, for those tests that
require electricity production, the facility has a 1.2-MW two-stage turbine in a
Rankine cycle designed to operate with 520ºC 100-bar superheated steam
2.2.2 The 2.7-MWth SSPS-CRS Facility
The SSPS-CRS plant was inaugurated as part of the International Energy
Agency’s SSPS project (Small Solar Power Systems) in September 1981.
Originally an electricity production demonstration plant, it used a receiver
cooled by liquid sodium that also acted as the thermal storage medium. At the
present time, as with the CESA-I plant, it is a test facility devoted mainly to
testing small solar receivers in the 200 to 350-kW th capacity range. The heliostat
field is made up of 91 39.3-m 2 first generation Martin-Marietta units. A
second field north of it has 20 52-m 2 and 65-m 2 second generation MBB and
Asinel heliostats that can be used as support. The CRS heliostat field has recently
been improved with the replacement of all the reflective facets, which
now have a lightweight structure and low-iron glass. The most innovative feature
are the completely autonomous intelligent heliostat-control units installed
in 2003, powered by photovoltaic energy and communicating the entire field
by radio by a concept developed and patented by PSA researchers. This first
autonomous heliostat field, which does not require the use of channels or cabling,
was made possible by financial assistance from the Ministry of Science
and Technology’s PROFIT program.
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