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

III. A - 9. IPROB=2, Sing1 e Calculational Time-DELS 0 L calculates the perfor-
mance only at UTIME hours past solar noon (UTIME is negative in the morning)
on the UDAY day of the year (Namelist BASIC).
III. A-4. IPROB=S, Matriz of Sun Angles-Instead of calculating performances
at certain specified times, this option allows the user to obtain the performance
at certain specified sun angles. NUAZ values of the azimuthal angle, UAZ, and
NUEL values of the zenith angle, UEL, are considered in all possible pairwise
combinations.
III.A-5. Selection of NYEAR, HRDEL, and Reference Times-Both accuracy
and calculational time of the performance calculation (but not the optimization
calculational time) increase with the number of day and hourly time steps chosen.
Fortunately, a relatively few days (3 to 5) and a reasonable time step (1 hour)
appear to produce accuracies better than 1%. Generally, it is better to decrease
HRDEL than to increase NYEAR when attempting to increase accuracy.
Two times of the year have special significance. First, REFTIM hours past
noon on the REFDAY day of the year is called the reference time. This is the
time of the year which is used to determine the design point power levels of the
system, as described in Section 1V.C-1. Second, HCANT hours past noon of the
DCANT day is used to determine the off-axis canting of heliostats, if any, as de-
scribed in Section 1I.D-2. The reference time must correspond to one cal-
culational time. In addition, daily start-up and shutdown times are determined
by the user-specified zenith angle, ASTART (< 90").
Default values are:
NYEAR = 5
HRDEL = 1.0
ASTART = 75.0"
REFTIM = 0.0 (solar noon)
REFDAY = 81.0 (equinox, March 21)
HCANT = 0.0
DCANT = 81.0
1II.B. Seasonal and Daily Variation of Sun Positions and Sunshape
The performance of a system is dependent on the position of the sun, the ac-
tual insolation, the shape of the sun, and weather effects, all of which can vary
with time.
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