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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The final step of cavity receiver optimization is to fine tune the shape of<br />
the heat exchanger surface within the cavity. The heat absorbing surface<br />
of a cavity is modeled as a segment of a right circular cylinder centered<br />
horizontally on the cavity aperture, as described in Sections 1I.E and V.A-<br />
5(b). It is possible, based on the choice of the value H (Namelist REC),<br />
that after optimization the top portion of the heat absorbing surface may<br />
either have too low a flux or too high a flux. In the <strong>for</strong>mer case, the re-<br />
ceiver may be oversized, and the user should rerun the second half of the<br />
optimization (IOPTUM=l) using a different value of H in Namelist REC<br />
to limit the heat absorbing surface height. In the latter case, the inter-<br />
nal flux spillage onto uncooled surfaces such as the roof may cause design<br />
failures, and so the user should rerun the second half of the optimization<br />
using a larger heat absorber height. After the design has been finalized,<br />
the user should run a final per<strong>for</strong>mance calculation of the optimum sys-<br />
tern to generate detailed flux maps on the heat absorbing surface or other<br />
surfaces of concern. If necessary, the user can then manually trim the heat<br />
absorber to eliminate aFeaS whose incident energy is low enough to not re-<br />
quire active cooling. However, if manual trimming is done, the user will<br />
also have to recalculate by hand the cost of the receiver and any energy<br />
costs, since no capital cost calculations are done during a final per<strong>for</strong>-<br />
mance calculation.<br />
If the user allows the heat absorber height to be as large as possible dur-<br />
ing optimization, as defined by equations V.A-8 and V.A-9, it is possible<br />
that this calculated height will be very sensitive to the minimum radius<br />
(RADMIN, Namelist FIELD). While it may be desirable to use the high<br />
per<strong>for</strong>mance heliostats nearest to the tower, it may not be cost effective<br />
because of the increased receiver costs. The user may wish to repeat the<br />
cavity optimization procedure with a different value <strong>for</strong> RADMIN to in-<br />
vestigate the sensitivity to this effect. However, it is likely that limiting<br />
the heat, absorber height by specifying H (Namelist REC) will result in<br />
similar receiver cost reductions without requiring the elimination of he-<br />
liostats, so that varying RADMIN should be done after trying all other<br />
optimization possibilities.<br />
IV.C-4. Tower Position (Land Constrained Only)-In a system with a land<br />
constraint (NLAND>O, Namelist FIELD), DELSOL will search <strong>for</strong> the optimal<br />
position <strong>for</strong> the tower in the field. The tower does not have to be within the land<br />
constraint; only the heliostats must be within the constraint. The code considers<br />
NUMPOS (520) equally spaced discrete positions of the tower from (XTPST,<br />
YTPST) to (XTPEND, YTPEND). The units <strong>for</strong> these variables are meters east<br />
(<strong>for</strong> XTPST and XTPEND) or meters north (YTPST, YTPEND) of the center of<br />
the first land constraint rectangle. (Also see Sections 1I.B-4 and 1V.D-2.)<br />
I V. C-5. Storage Capacity-DELSOL sizes storage during system optimiza-<br />
tion based on the longest operating day. (See Section V.A-8 <strong>for</strong> how storage sizes<br />
are calculated.) The code assumes that by thus sizing storage no energy will be<br />
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