A User's Manual for DELSOL3 - prod.sandia.gov - Sandia National ...

1I.C. Heliostat Pattern and Density
It is assumed that the heliostats are arranged in the radial stagger pattern
illustrated in Figure 11-9. They lie on isoazimuthal and isoradial lines. The local
heliostat density, p, (Le., the ratio of mirror area to land area) is related to the
local row spacing, AR, and azimuthal spacing, AAz, by the equation:
p = DENSMR x WM x HM x ROUNDI(ARAAZI2) (11.C - 1)
where DENSMR =fraction of mirror area of a heliostat whose overall
dimensions are WMx HM
WM =heliostat width (meters)
HM =heliostat height (meters)
1.0 rectangular heliostats
ROUND = { n14
circular heliostats
AR =radial distance between heliostat centers (note that because
of the stagger arrangement of heliostats, this distance is
twice the distance between rows of heliostats) (meters)
AAz =azimuthal distance between heliostat centers at a given
radial distance from the tower (meters)
I'
The choice of heliostat density is indicated by the value of the variable
IDENS. For IDENS = 1, 2, or 4, the values of AR and AAz are curve fits to op-
timized field layouts reported by the University of Houston (References 4, 9, 10,
and ll), with a correction factor dependent on tower height for applications to
small systems (IDENS = 1 or 2).
a) IDENS = 1 High reflectivity (-0.9), rectangular heliostats
AR = (1.14424cot6~ - 1.0935 + 3.06848~ - 1.12566~')HM (1I.C - 2)
where K(THT) = (1 - zxTHTxRADIUS
HMxAR
)-l
and 6~ = E - 6t (see Figure 11-2). RADIUS (in meters) is the radius
from the tower base and HM is the height of the heliostat (in meters).
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