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

111. Detailed Performance Calculation
In a performance calculation, the user specifies a complete system design and
the code calculates the performance of the system. This calculation includes the
effects of cosine losses, shadowing, blocking, atmospheric attenuation, and spillage
of a field at a given time, at a given sun angle, over a specific day, or over an en-
tire year. A detailed performance calculation gives the required results for use in
optimization calculations, and a performance calculation can be done for a system
which has been optimized by DELSOL. This latter calculation may also include
an annual energy calculation as well as an annual field efficiency calculation.
1II.A. Performance Calculation Options
DELSOL will calculate the performance of a central receiver system at a sin-
gle time, over a single day, on a user defined matrix of sun positions, or over the
year, depending on the chosen value of the variable IPROB (Namelist BASIC).
III.A-1 IPROB=O or 4, Annual Performance-DELSOL calculates the per-
formance at a finite number of times during the year and integrates to get daily
and annual averages. The problem is simplified by the daily and seasonal symme-
try of clear sky insolation, described in Section 1II.B. Only the half year between
winter and summer solstice and the times between solar noon and sunset need to
be sampled. NYEAR equally spaced days starting at December 21 (day 354.75)
and ending on June 21 (day 172.25) are considered, as illustrated in Table 111-1.
At each of these days the time is varied from solar noon until sunset in steps of
HRDEL hours, also shown in Table 111-1. The last time step at each day is taken
as the time when the sun angle, e,, is ASTART degrees from the vertical.
IPROB=4 is specified when the results of the performance calculation are
needed in order to do an optimization calculation. For this option, annual
field efficiencies are calculated. The performance should be saved by specifying
ITAPE=l (Namelist BASIC).
IPROB=O is specified when a final detailed performance calculation is de-
sired. This calculation can be done for a system which was previously optimized
by DELSOL or for a user specified system. This option calculates annual field
performance, and also calculates annual energy for the specified system. If the
performance of a previously optimized DELSOL system is being requested, the
user should specify ITAPE=3 to indicate that the system is to be obtained from
the file which was written during the optimization procedure.
I1I.A-2. IPROB=l, Single Calculational Day-DELSOL calculates the per-
formance only on the UDAY (Namelist BASIC) day of the year. No annual av-
erage is calculated. The time steps are controlled by HRDEL as described for
IPROB=O.
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