A User's Manual for DELSOL3 - prod.sandia.gov - Sandia National ...
A User's Manual for DELSOL3 - prod.sandia.gov - Sandia National ...
A User's Manual for DELSOL3 - prod.sandia.gov - Sandia National ...
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,<br />
flux level. DELSOL determines the best combination of receiver size (with its<br />
associated cost, receiver losses, and spillage losses) and heliostat field size (with<br />
its associated cost and field losses). For a given set of component costs, as a re-<br />
ceiver size decreases below its optimum, spillage increases and so field costs in-<br />
crease more than the decrease in receiver cost. If at that receiver size the allow-<br />
able flux limit is not reached, then it is not cost effective to <strong>for</strong>ce the system to<br />
have a peak flux at the FLXLIM(1) limit.<br />
The second reason why a peak flux limit may not be obtained during system<br />
optimization is that the receiver size is being varied in discrete steps, rather than<br />
continuously. In this case, the user can come closer to a given flux limit by using<br />
more closely spaced receiver sizes, or the flux limit can be set slightly higher than<br />
actually desired since the flux from the optimum will generally be below the limit.<br />
In any case, the user should request a more accurate detailed flux map during a<br />
final per<strong>for</strong>mance calculation to verify that flux limits are being met, if desired,<br />
but not exceeded.<br />
1V.D-2. Iieliostat Field Land Constraint-DELSOL allows the heliostat field<br />
to be constrained within a number of arbitrarily oriented rectangles. The input<br />
defining the land constraint is described in Section I1.B-4. As mentioned in Sec-<br />
tion 1V.C-4, with a land constraint it. is necessary to search <strong>for</strong> the optimal loca-<br />
tion of the tower with respect to the constraint. Only the heliostat locations are<br />
constrained. The code does not require the tower to be in the land constraint.<br />
However, the user should make sure that land is available <strong>for</strong> the tower.<br />
There is an additional complication in land constrained designs when the<br />
thermal energy is not used at the base of the tower. In repowering or process<br />
heat applications the thermal energy may have to be transported to a point near<br />
the edge of the land constraint. DELSOL does not consider the cost or losses in<br />
the piping run from the tower position to the use point. The user may want to<br />
fold in these effects manually. For example, consider a rectangular land constraint<br />
whose sides are parallel to the N/S and E/W directions. DELSOL will gener-<br />
ally prefer to locate the tower south of the center of the land constraint. Sup-<br />
pose, however, that the thermal energy is required at the northern boundary of<br />
the field. It may then be cost effective to move the tower further north from the<br />
DELSOL optimum if the savings in the pipe run may more than offset the in-<br />
creased cost of thermal energy at the tower base.<br />
1V.E. “Smart” Optimization Searching Algorithm<br />
DELSOL has to consider NUMTHT x NUMREC x NUMHTW x NUMPOS<br />
combinations of tower height, receiver sizes, and tower positions in searching <strong>for</strong><br />
the minimum energy cost system. Figure IV-1 shows a schematic of the opti-<br />
mization search. There are four nested iterations of the discrete system variables:<br />
tower height, first receiver variable, second receiver variable, and tower position.<br />
Since the zone by zone per<strong>for</strong>mances do not depend on the tower location, these<br />
per<strong>for</strong>mances are calculated outside of the tower position loop. For each set of