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

For the final detailed performance calculation on the optimized system, the
input set of Table A-2 is included. ITAPE=3 specifies that a user defined sys-
tem is to be read from the file on Unit 30, and TDESP indicates the power level
in MW of the system to be analyzed. IPROB=O specifies that an annual perfor-
mance is desired. Since a flux map is desired, the flux calculation must be turned
on with IFLX=l, where IFXOUT determines which point in time is to be used
for the flux calculation. The flux point positions default to the positions defined
in the previous optimization calculation, since they are not specifically redefined.
Comments on Output
The initial output is similar to the output of Problems la and 2a. Note that
the code chose the same system design as in Problem 2a. The smart user proba-
bly would have used a finer grid of flux test points and of tower height and aper-
ture width optimization variables to further refine the system in this step.
The form of the remaining output is the same as for Problem lb. The opti-
mized storage size is printed at the front of the annual power production table. In
this case the size was unchanged from that for the longest day of the year (used
earlier during system optimization). If the storage size had changed due to opti-
mization, the cost numbers also printed there would have been adjusted by the
code and would no longer have matched those numbers printed as part of system
optimization output. These new numbers are the best numbers DELSOL can pro-
vide. The levelized cost of energy printed here may also be different because the
final performance calculation predicts a more accurate annual energy estimate,
which is printed in the yearly energy production summary and is used in this en-
ergy cost calculation.
The flux map shows that at angles greater than those by which the field
"sees" the cavity wall, flux is negligible. However, at the top of the wall the flux
is still significant. The user might wish to reoptimiee this system to allow a larger
wall height for the same aperture dimensions. Also, Sample Problem 3b will show
how to examine the roof of a similar cavity design for fluxes. The active cavity
area should only be enlarged to limit fluxes on uncooled surface (such as the roof)
to acceptable values. Internal reradiation will occur so that the energy incident
on uncooled surfaces will mostly not be lost for power production purposes.
2 14