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Title: Development of sheet molding compound solar collectors with molded-in silvered glass reflective surfaces

Technical Report ·
DOI:https://doi.org/10.2172/7081344· OSTI ID:7081344

The reflecting concentrator of a parabolic trough solar collector system comprises approximately 40% of initial system cost. The parabolic concentrator structure is also the most influential component in determining overall system efficiency. Parabolic test moldings have been fabricated from a general purpose sheet molding compound with flat chemically strengthened glass, flat annealed glass, and thermally formed glass. The test panel configuration was a 1.22 m x 0.61 m, 45/sup 0/ rim angle (0.762 m focal length) parabola. Attempts to mold with annealed sheet glass (1 mm thick) and thermally formed glass (1.25 mm thick) were unsuccessful; only the chemically strengthened glass (1.25 mm thick) was strong enough to survive molding pressures. Because of the mismatch in thermal expansion between glass and sheet molding compound, the as-molded panels contained a sizeable residual stress. The results are given of dimensional changes taking place in the panels under accelerated thermal cycling and outdoor aging conditions; these results are compared to an analytical model of the laminate. In addition, the sheet molding compound has been examined for thermomechanical properties and flow behavior in the rib sections. Results indicated that lowering the thermal expansion coefficient of the sheet molding compound through material modifications would produce a more stable structure.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
7081344
Report Number(s):
SAND-80-0702
Country of Publication:
United States
Language:
English