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

VI. Program Flow
DELSOL can be used in two ways: to do a detailed performance calculation
for a system which is completely defined by the user, or to define by optimization
a system having a lowest energy cost and then do a detailed performance calcu-
lation on that system. For the first case, no optimization, annual energy calcula-
tion, or system cost calculations are done. Heliostat field zoning and zone helio-
stat densities must be specified, along with desired receiver and tower dimensions.
In fact, every default variable in the BASIC, FIELD, HSTAT, REC, and NLEFF
Namelists should be examined 'to verify that the proper system is being examined.
Even then, no energy calculations will be done, and no costs will be assigned to
the system, but only field efficiencies and flux densities will be calculated. A user
defined system should be examined by specifying IPROBf4 (Namelist BASIC)
and IUSERF-2 or 3 (Namelist FIELD).
The most useful function of DELSOL, that of finding an optimum system de-
sign, has three calculational steps and several minor steps. The main steps are
to do an initial performance calculation, to optimize several variables using the
results from the initial performance calculation, and to do a final performance cal-
culation on the optimum system. These steps fit into the list of actions suggested
for optimization in Table VI-1.
Hefore any calculations are done, the user must still take the time and effort
to see that the DELSOL defaults describe the proper system. Specification of the
site, field boundaries, heliostat design, and receiver type are generally straight-
forward. However, determining receiver thermal losses and system costs can be
much more involved. The radiation and convection losses depend on receiver ge-
ometry, receiver material, temperature, and ambient conditions. The system costs
depend on the technology and applications. Detailed cost estimation may be re-
quired to generate the input to DELSOL. In addition to the direct capital costs,
operating and maintenance costs must be estimated. Finally, the economic pa-
rameters suitable for the intended application of the system have to be specified.
The initial performance calculation is required as a first step for optimiz-
ing a system design, since the results will be scaled to give the performance of
the different systems in searching for the optimum design. The specifications of
receiver type (IREC) and field type (INORTH) should be consistent with each
other and with the system to be designed. Annual field performance will be cal-
culated at this time for every zone in the heliostat zonal pattern. This involves
finding the image shapes for heliostats from every zone. However, no power limi-
tation is yet imposed on the system, so heliostat aiming strategies will not affect
the results, except that using multiple aimpoints will increase the computational
time directly. Thus, during the initial performance run, a single aimpoint strat-
egy should be used. Also, because the heliostat field has not yet been optimized
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