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

To directly specify such a field, the following variables must be defined: (1) RAD-
MIN, RADMAX, NRAD, NAZM, INORTH, and AMAXN, to set up the zoning;
and (2) NRADMN, NRADMX, DENSIT, AZMSEP, and FLAND, to character-
ize the field zone by zone. In addition, for a performance calculation on a system
optimized by DELSOL (where the results were saved on a file by specifying IO-
TAPE=l in namelist OPT), all of the above variables can be read from the file
by specifying ITAPE=3. In this case, IUSERF=2 will be the code default, and
should not be set by the user to any other value.
For the Lth azimuthal zone (L=l, NAZM) as numbered in Figure 11-4, all ra-
dial zones are occupied from the minimum radial zone number, NRADMN(L),
through the maximum radial zone number, NRADMX(L). If no zones are oc-
cupied in the Lth azimuthal zone, then NRADMN(L)=NRADMX(L)=O. The
radial/azimuthal zone boundaries may not exactly match the boundaries of the
user’s field. The FLAND array can be used to trim the DELSOL zoning. If there
is a land constraint, FLAND will be calculated automatically by DELSOL. In the
absence of a land constraint, the user may specify FLAND. For the (K,L) zone,
FLAND(K,L) is the fraction of the land area in the (K,L) zone that is occupied
by the heliostat field. If the whole zone is occupied, FLAND(K,L)=l.O; if half the
zone is occupied, FLAND(K,L)=0.5, etc. Field averaged performance is calcu-
lated and reported using this option. This option cannot be used for any initial
performance run which will be used later for a field buildup (optimization) run.
d) IUSERF-3
This option allows the user to specify the x and y (east and north) coordi-
nates of the base of every heliostat relative to the tower base. For the perfor-
mance at a single time (IPROB=2, namelist BASIC), an asymmetrical heliostat
field can be used. However, in order to calculate daily or annual performances the
field must be symmetric about the N-S axis.
A special convention is used to group and number the heliostats. The he-
liostats are grouped into “rows” as illustrated in Figure 11-7. In a field that sur-
rounds the receiver the rows will usually be completely or partially filled circles.
In a north-only field the rows will be arcs or lines. The rows do not intersect.
The rows are numbered starting with the row nearest the tower and proceeding
outward. Within each row the heliostats are numbered starting with the heliostat
on the N/S line or just east of the N/S line. The numbering increases in a clock-
wise manner around the tower. Note that for a line or arc of heliostats (see row
4 in Figure 11-7) the number starts in the middle, proceeds to the eastern edge,
goes to the western edge and then heads to the middle again. The code considers
the shading and blocking by only those heliostats within f two rows of the row in
which the heliostat of interest is located.
For any of the options described above, the number of zones and hence the
accuracy increases as NRAD and NAZM increase. The tradeoff is that computing
time and cost will also increase. The variation in execution time is approximately
linear with the number of zones, while the increase in accuracy with the number
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