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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owing, blocking, atmospheric attenuation, spillage, and flux profiles. The code has<br />
several special features. First, the running time <strong>for</strong> a single per<strong>for</strong>mance calcula-<br />
tion is much less than <strong>for</strong> other codes, such as MIRVAL (Reference l), but with<br />
the same accuracy <strong>for</strong> most problems. Second, because of the analytical <strong>for</strong>m of<br />
the spillage and flux, one annual per<strong>for</strong>mance calculation determines the per<strong>for</strong>-<br />
mance <strong>for</strong> any tower height or receiver size. Other codes must per<strong>for</strong>m a new<br />
calculation each time the system is varied. DELSOL, there<strong>for</strong>e, has a very sig-<br />
nificant advantage in the execution time required <strong>for</strong> the large number of per<strong>for</strong>-<br />
mance calculations necessary in design tradeoff and optimization studies. Third,<br />
DELSOL contains a detailed description of the types of errors that can degrade<br />
the per<strong>for</strong>mance of heliostats. Finally, DELSOL is relatively easy to use. With<br />
minimal input, DELSOL can analyze systems involving flat, focused, or canted<br />
heliostats with round or rectangular shapes; external, multiple aperture cavity, or<br />
multiple flat plate receivers; and variable aiming strategies.<br />
As a system design tool, DELSOL determines the best combination of field<br />
layout, heliostat density, tower height, receiver size and tower position (land con-<br />
strained system) based on the per<strong>for</strong>mance, total plant capital cost, and system<br />
energy cost. In this mode, the code can be used to define values of the key design<br />
parameters on which a detailed design can be based. The need <strong>for</strong> manually do-<br />
ing a succession of point designs in order to identify an optimum is eliminated.<br />
The optimal design is evaluated by searching over a range of tower heights and<br />
over two components of the receiver geometry (e. g., diameter and height of an<br />
external receiver) at the design point power level(s) to find the system with the<br />
minimum energy cost. The code is also capable of doing constrained optimiza-<br />
tions in which the peak flux on the receiver is restricted below some maximum<br />
value and/or land availability is limited.<br />
The development of DELSOL followed that of <strong>Sandia</strong>’s other two central re-<br />
ceiver per<strong>for</strong>mance codes, MIRVAL and HELIOS (References 1 and 2). The ear-<br />
lier codes have been used to validate the theory and programming in DELSOL.<br />
The agreement in per<strong>for</strong>mance predictions among the three codes is discussed in<br />
Chapter VII. While any one of the codes can, in principle, do the same kinds of<br />
problems, they were developed with different purposes in mind and thus do not<br />
greatly overlap in use. HELIOS is specially adapted <strong>for</strong> analyzing experiments<br />
at <strong>Sandia</strong>’s Central Receiver Test Facility. MIRVAL employs a Monte Carlo ray<br />
trace technique, giving it the potential to analyze very complex systems that are<br />
well defined. DELSOL has been developed with speed in mind; hence it typically<br />
requires much less computer time <strong>for</strong> per<strong>for</strong>mance calculations, and it can also<br />
readily handle the multiple per<strong>for</strong>mance calculations required <strong>for</strong> system design<br />
and optimization.<br />
DELSOL is based in part on the per<strong>for</strong>mance/design approaches developed<br />
at the University of Houston (References 3 and 4), but with many important<br />
additions. The mathematical basis is an analytical Hermite polynomial expan-<br />
sion/convolution of moments method <strong>for</strong> predicting the images from heliostats<br />
(Reference 3). The method has been extended at <strong>Sandia</strong> to allow a more general<br />
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