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

DELSOL will examine NUMHTW (520) equally spaced discrete values of
RY(l)/RX(l) from a minimum of HTWST to a maximum of HTWEND.
If NUMREC or NUMHTW is set to 1, the value of the receiver vari-
able will be fixed to be the last defined value of the appropriate variable
(RX(1) or RY(1)) in Namelist REC.
In the case of multiple flat plate receivers, all receiver dimensions are
assumed proportional to the first receiver’s dimensions. RX2TRX,
RX3TRX, and RX4TRX are the ratios of the second, third, and fourth
plate’s horizontal dimension to the first plate’s horizontal dimension. The
vertical/horizontal ratio, RYTRX, is assumed the same for all plates.
c) Cavity Receiver Dimensions and Optimization-DELSOL assumes during
optimization that a cavity receiver has an aperture which can be treated
like a flat plate receiver as described above. It also assumes that the cav-
ity is shaped as a semicircular right cylinder centered horizontally on the
aperture, so that the heat absorbing surface depth needs to be deter-
mined. Further, the optimum height of the heat absorbing surface should
be determined, in order to find an optimum system based on levelized en-
ergy cost (LEC). These are more design parameters than DELSOL can
vary at one time, thus making cavity receivers more complicated to design
than other receiver types. However, because varying some of these vari-
ables does not affect the optimum choice (based on LEC) of other of the
variables, it is possible to run a series of optimization and performance
runs that will lead to a “good” cavity design. This is especially true be-
cause almost all power calculations for cavities are done at the aperture
(all except convective losses), so that power and energy are nearly inde-
pendent of the configuration of the interior of the cavity. Thus, cavity
depth and heat absorber height, which depend on flux levels and cost, can
be optimized separately from aperture dimensions without affecting the
optimum choice of those variables.
Different pairs of receiver variables are selected in sequence for optimiza-
tion. First, the width of the aperture and depth of the cavity should be
optimized by specifying IOPTUM=2. Second, the aspect ratio of the
aperture can be optimized separately (IOPTUM= 1). Finally, performance
runs can be used to generate flux maps within the cavity so that the user
can trim or adjust the shape of the heat absorbing surface, if desired or
required.
The first step in optimizing a cavity is to determine the aperture width
and cavity depth by specifying the variable IOPTUM=2. DELSOL
searches NUMREC equally spaced discrete values of the width of the first
(north) aperture, RX(l), from a minimum value of WST meters to a max-
imum value of WEND meters. The relative aperture height, RY(l), will
remain fixed as specified by the value of RYTRX, and the dimensions of