Abstract:
The design of a solar dish usually involves the complex trade-off between cost and optical quality. The use of
off-the-shelf elliptical television antennas in a vacuum-membrane solar dish array is investigated in this paper, in an effort
to reduce the cost of solar concentration. Each facet comprised a 50-ȝm-thick Mylar sheet membrane, stretched and sealed
over the elliptical rim of an off-the-shelf satellite television antenna, forming a narrow cavity in which a vacuum could be
drawn to pull the Mylar sheet into a concave shape. The shape of the facet concavity was investigated using
photogrammetry. An elliptic paraboloid and a hemi-ellipsoid were fitted to the photogrammetry results, and it was
determined that both fits could be used to represent the concave shape. The investigation allowed for the concave shape to
be modelled in a ray tracing analysis, where the flux map was compared with the result from a lunar flux mapping analysis.
Comparison of the intercept factor trends showed that further investigation into quantifying the contributions of individual
facet alignment errors should be performed to further improve the model. With improvements in individual facet alignment,
the use of off-the-shelf elliptical television antennas in a vacuum-membrane solar dish array can be a viable solution to
reduce the cost of solar concentration.
