Optical evaluation of prototype stretched - membrane mirror modules for solar central receivers

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7102861

Alpert, D J; Houser, R M

Under contract to Sandia National Laboratories, two independent studies were performed to develop a commercial-scale heliostat design and to assess the fabrication and costs of stretched-membrane heliostats. The studies, performed by Solar Kinetics, Inc., and Science Applications International Corp., concluded that stretched-membrane heliostats would cost between 15% and 20% less than comparable glass-mirror designs. As part of these studies, 50-square-meter prototype mirror modules were built and installed for testing at the Central Receiver Test Facility (CRTR) at Sandia. Major issues addressed in our testing program included the optical performance of the stretched-membrane mirror, the performance of the mirror's focus-control system in windy conditions, the performance of the defocus system, and the durability of the reflective film. The results of the evaluation indicate that the optical performance of SKI's first-of-a-kind mirror module is at least as good as that of current glass-mirror designs. In calm conditions, the mirror can be defocused to a convex focal length of -200 meters in 7 seconds. The optical performance on windy days is within Sandia's heliostat specifications. After 2 years of exposure, the reflective surface was generally in good condition, having a clean reflectivity of nearly 90%.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7102861
• Report Number(s): SAND-87-2886C; CONF-880655-4; ON: DE88011884
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140702* -- Solar Thermal Power Systems-- Central Receiver
141000 -- Solar Collectors & Concentrators
DESIGN
EQUIPMENT
FABRICATION
FILMS
HELIOSTATS
MEMBRANES
NATIONAL ORGANIZATIONS
RESEARCH PROGRAMS
SOLAR EQUIPMENT
US DOE
US ORGANIZATIONS