Technological constraints, materials availability, production capacity, and manufacturing and installations plans and costs at different production levels are included in a study of concentrating collector industrialization. As cobalt for the engine and receiver is supply limited, alternative lower temperature alloys and higher temperature materials such as ceramics are discussed. Economics and production efficiency favor co-location of cellular and thin glass production for reflectors. Assembly and installation are expensive for small sites and few alternatives exist to apply mass production techniques to lower these costs for the selected design. Stepping motors in the size and quantities required are not commercially available today but could be in the future

Butterfield, J. F.

English

NASA Technical Reports Server

N80 24'789
A STUDY OF MASS PRODUCTION AND INSTALLATION
OF SMALL SOLAR ',rHERMAL ELECTRIC POWER SYSTEMS
J. Butterfield
Arthur D. Little, Inc.
One Maritime Plaza
San Francisco, California
ABSTRACT
This study of concentrating collector industrialization included
technological constraints, materials availability, production capacity,
and manufacturing and installations plans and costs at different
production levels. Several constraints were identified.
Cobalt, for the engine and receiver, is supply limited. Alternative
lower temperature alloys and higher temperature materials (ceramics) are
discussed. Economics and production efficiency favor co-location of
cellular and thin glass production for reflectors. Assembly and
installation are expensive for small sites and few alternatives exist to
apply
 mass production techniques to lower these costs for the selected
design. Stepping motors in the size and quantities required are not
commercially available today but could be in the future.
The study concluded that additional development should be concentrated on
design modification to permit industrialization of the assembly and
installation process, the use of alternative materials in the
engine/receiver subsystem, the design'of motors and gearboxes matched to
concentrator requirements, and development of an integrated process for
reflector production.
PROJECT DESCRIPTION
This project is based on a conceptual design of a concentrating solar
collector system developed by Jet Propulsion Laboratories. The hardware
elements of the system were divided into four basic component packages:
•	 Power Conversion Component	 including the
receiver, engine, and generator units.
•	 Reflector Component -- including second surface
"thin" glass mirrors, cellular glass support gores,
and mounting hardware.
•	 Structure and Foundations Component--- including
receiver and engine support structure, reflector
support ring structure, ballast support structure,
intermediate structure, pedestal, pedestal
foundation, and intermediate structure track and
foundation.
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https://ntrs.nasa.gov/search.jsp?R=19800016296 2020-03-21T18:58:45+00:00Z
4. -
•	 Drive and Control, Component -- including the
elevation actuator, azimuth drive, two-axis shadow
band sun sensor, on-board controller, and power
communication connections.
Each component was described in terms of the process steps and materials
and equipment needed for the manufacture of 5,000, 50,000, and 500,000
concentrators per year. The transportation requirements from points of
manufacture to installation sites and the on-site assembly and
installation processes and techniques were also developed. Based on the
criteria established for concentrating collector systems, the maximum
size of any one site would be 500 collectors or approximately 10
megawatts electric.
INDUSTRIALIZATION ISSUES
Materials-related Issues
in the course of the analysis two components of the system were found to
be resource limited -- the receiver and buffer storage units of the power
conversion package and the stepping motors and generator of both the
drive and control and power conversion components. In both instances
cobalt was the material in short supply that would tend to limit
industrialization.
The receiver and buffer storage units use cobalt in a high-temperature
superalloy called Haynes 188. At the intermediate volume level, 5Q,000
units per year, the concentrator manufacturer would use 27% of domestic
cobalt consumption; at 500,000 units per year the requirement would be
838 of the world's annual use. Since the dedication of these quantities
of cobalt for concentrator systems is unrealistic in view of the current
priority uses of cobalt, two other high-temperature alloys were
investigated and found to be practical if the design temperature were
lowered by 1000F. These alloys are Inconel 601 and Incoloy 800H.
In addition to being commercially available in the necessary quantities,
these alloys possess two other advantages; they are considerably less
expensive and more workable than the cobalt alloy. In the longer term,
ceramics - particularly sintered silicon carbide and hot pressed silicon
nitride -- offer both cost and higher operating temperature advantages.
However, 10-20 years of research and development will be needed to
develop the strength requirements necessary for solar applications and
the processing technology to obtain net or near net shapes in ceramic
products.
The generator in the power conversion component and both of the stepping
motor drives use cobalt in their permanent magnets. Although the
quantity of cobal.` in any one unit is relatively small, at the higher
volume levels the total material requirement is significant. However,
alternative designs using wound coil units have been designed and
212
produced commercially. Although such units carry a premium cost, they
have an offsetting advantage of being capable of higher torque than units
currently produced with permanent magnets. Hither torque driven, in
turn, permit simplification of the gear drive units without significant
degradation in the pointing accuracy of the drives.
Process TechnoloSX Issues
Although the manufacturing technology for all of the components of a
concentrating collector system exists in industry today, two important
developments must still, be made. In the case of the power conversion
component, the majority of the elements, although similar to automotive,
aircraft, or gas turbine technology, contain one or two differences which
will limit volume production. The first is industrial capacity. Vor the
cellular glass gores, the thin glass reflector, the engine recuperator,
receiver, and buffer storage units and stepping motors, industrial
capacity exists to fabricate the units needed for the collector system at
the 5000 unit annual volume but not at the 50,000 unit per year level.
In some instances, such as for reflectors, it can be argued that the
separate locations of existing industrial production are inappropriate
for the process needs of solar collectors. Nevertheless, in virtually
every instance the potential- fabri cators of the units or subsystems would
be drawn into plant and equipment investments based on the growth of
viable collector system business.
A separate problem exists for components such as structures and
foundations. The components of a collector system are by design high
bulk-low value elements. As a result,it is highly desirable, indeed
necessary, to subcontract or otherwise locate the production facilities
for these components on a regional basis to minimize transport costs. At
higher volumes of production this poses little if any problem but at the
Lower end of the volume scale, transportation costs represent an
impediment to industrialization.
Site-specific Issues
The conceptual design of the concentrating collector employs an 11-meter
diameter dish, long and heavy structural components, and components such
as reinforced precast concrete foundations and drive, control, and power
conversion packages that are unlikely to be fabricated in the same
production plants. As a result large concentrator systems are not
transportable when fully assembled; therefore, a site assembly process is
required. in addition, since alignment of the reflector panels, engine,
and sun sensing mechanism is critical, a portion of the assembly process
on site must be conducted in a protected environment. When this factor
is combined with the relatively small number of units to be located at
any one site, the result is not only a relatively costly assembly and
installation charge but also an essentially flat cost curve relative to
increasing annual production volumes.
Concentrator Costs
A summary of the costs associated with an installed collector iv,
contained in Table 1 below.
213
TABLE 1
SUMMARY OF COMPONENT AND PROCESS COSTS FOR
THE CONCEPTUAL DESIGN OP A CONCENTRATING SOLAR COLLECTOR
Per Unit Costs in
Third Quarter 1979 Dollars
51000	 50,000	 500,000
Concentrator Concentrator Concentrator
	
Units Yr	 Units Yr	 U'nits/Yr^,
;Power Conversion component
	 $25,250	 $12 , 300	 $ 6,925
Reflector Component	 21136	 1,747	 1,747
Structure, Poundat4,on,
Assembly, and Installation	 16,060	 12,706	 12,592
Driv°N and 4lIItLVls 	 S/36F	 4,174	 3,656
«.. -.
Installed Cost/Concentrator	 $0,832	 $30,927	 $24,920
As can be seen, the components which are produced in traditional
manufacturing plants such as the power conversion package, drives and
controls, and reflectors demonstrate cost reductions with increasing
volume. Costs for the structures, foundation, assembly, and
installation, however, are relatively constant at high and intermediate
volumes and are sharply increased at low volumes due to the higher costs
of fabricated structural elements and transportation and limited
applicability oC "mass production" techniques.
AREAS FOR FURTHER RESEARCH
Since the conceptual design for a concentrating collector system is but
the first in a series of designs, the costs estimated in this study
should be utilized as an indication of where effort should be expended to
achieve cost reductions rather than as absolute or immutable values.
Based on these costs the primary benefits of redesign efforts or of
alternative designs may be experienced by increasing the
industrialization associated with structures, foundations, assembly, and
installation. Three possibilities suggest themselves:
•
	
	 Smaller concentrators which require less field
assembly and installation processing may permit
reductions in cost with increasing volume.
•
	
	 Larger sites of up to and over 50 	 megawatts electric
will favor mechanization and automation of site
processes and tend to drive costs lower.
214
r	 Alternative designs that permit subassembly of
component parts of a collector system in the
fabrication planto will permit reductions in
site-related activities and, more importantly, will
tend to retain collector costs on an experience
curve related to volumes produced.
in addition to the points indicated above, other components of the
collector system will either require or benefit from further development
activity. These includes
•	 Directed development of ceramics for the receiver
and buffer storage units.
•	 The involvement in the engine development program of
alternative suppliers to increase the source
availability.
•	 Co-development of drive motor and gearbox packages
matched to meet both the torque and accuracy
requirements of a collector system.
•	 integrated process development for complete
reflector panels. This would include gorse
fabrication and shaping, "thin" glans fabrication
and mirroring, lamination of the two components,
sealing, hardware installation, and environmental
testing.
215


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