An improved design for stretched-membrane heliostats
Science Applications International Corporation (SAIC) has developed an improved stretched-membrane heliostat mirror module under contract to Sandia National Laboratories, Albuquerque, New Mexico. Both a 150-m/sup 2/ commercial mirror module and a 50-m/sup 2/ prototype mirror module have been designed. The prototype mirror module has been fabricated and is being tested at the Central Receiver Test Facility (CRTF) in Albuquerque. Two .0762-mm (.003-in) thick stainless steel membranes are stressed to approximately 90 MPa (13,000 psi) and welded to either side of a carbon steel, rectangular cross-section ring, which is compressed to approximately one-tenth of its yield strength. The ring is supported by five trusses, which radiate from a central hub. The mirror module is mounted on a conventional pedestal drive system for sun-tracking purposes. The mirror module is air-tight, and focusing is achieved by modulating the position of the back membrane. The ring stiffness and tolerance achievable by conventional manufacturing methods dictate the ring distortions prior to installation of the mirror module. Once the mirror module is installed, wind loads on the heliostat exert additional out-of-plane loads. A comprehensive finite-element computer model of the mirror module was used for the structural design of the ring/membrane system and truss supports. The analysis and design methods used are reported, and an improved mirror module design is described. Preliminary test results indicate the prototype mirror module meets all design performance goals. The unit has a full cone angle reflected beam dispersion of 2.8 mrad and can defocus in five seconds. 25 refs., 77 figs., 17 tabs.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Science Applications International Corp., San Diego, CA (USA). Energy Projects Div.
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6110729
- Report Number(s):
- SAND-89-7027; ON: DE89013872
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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HELIOSTATS
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ENGINEERING DRAWINGS
FABRICATION
FINITE ELEMENT METHOD
MATERIALS
MIRRORS
SOLAR TRACKING SYSTEMS
STAINLESS STEEL-304L
STAINLESS STEELS
WELDING
ALLOYS
CHROMIUM ALLOYS
CHROMIUM-NICKEL STEELS
DIAGRAMS
EQUIPMENT
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
JOINING
LOW CARBON-HIGH ALLOY STEELS
NICKEL ALLOYS
NUMERICAL SOLUTION
SOLAR CELL ARRAYS
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR TRACKING
STEEL-CR19NI10-L
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CSP
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140702* - Solar Thermal Power Systems- Central Receiver
141000 - Solar Collectors & Concentrators