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

nSTOR is determined from an assumed maximum volume per tank:
VSTOR
nSTOR =
VTK,MAX
where V~TOR = total volume required for storage (m3)
VTK,MAX = maximum tank volume (m3)
For non-integer values, nSTOR is rounded to the next highest integer. The total
storage volume is related directly to the energy in storage:
VSTOR = VTK,REF
ESTOR,REF
where E~TOR is the energy in storage. The individual tank
volume is:
(V.A - 16)
(V.A - 17)
assuming that multiple tanks will be constructed of equal volume. If only a single
tank design is desired, the user can choose an appropriately large value for
VTK,MAX-
In DELSOL, storage is initially sized for the excess energy production on the
longest day, June 21st. This storage size is always calculated and used in the system
optimization process. The calculation of E~TOR is illustrated in Figure V-3.
Its value is determined by a numerical integration to give the shaded area in the
figure. The nominal number of hours of storage is simply E~TOR divided by PDES.
The assumption is made that this day will require the largest storage tank, so
that no energy is thrown away at any time during the year. However, for north
biased fields this assumption is not necessarily valid, since due to higher field efficiencies
at other days of the year the integrated value mentioned above could be
higher at another day than June 21, thus leading to discarded energy when the
storage tank is sized for June 21. On the other hand, it is possible that having a
smaller storage tank and discarding energy may be more cost effective than never
discarding energy. The user is therefore given the option of optimizing the storage
size to balance the cost of the storage tank against the cost of discarding energy.
This option, which is specified using the variables ISTR and NSTR (Section
1V.C-S), is requested as part of system optimization, but the storage optimization
and final storage tank cost calculation is done during a final performance calculation.
This is the only component cost which may be recalculated during a final
performance calculation.
Default values for calculating storage costs are based on a hot tank/cold tank
design:
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