7.1 Collector-Subsystem Models for MINSUN
A primary objective of the work of Subtask 1(b) was to provide reliable performance and cost models for use in system-optimization studies using the MINSUN system-optimization code developed by Subtask 1(a) for the Task VII studies. Tables 2.4-2.6 and 2.8 constitute the basis for the performance models developed for use with MINSUN; however, the nature of the calculational procedures employed by MINSUN makes an additional step necessary for implementation. MINSUN works with relatively large time steps (usually a day or a week); therefore, this code does not keep track of the time of day or the sun angles during its integration cycle. Because these variables are essential to proper calculation of the collector output, a preliminary calculational step was required in which the energy output of the collector for various inlet (storage) fluid temperatures was calculated by hour-by-hour simulation of the collectors represented in Tables 2.4-2.6. The daily integrals were then stored in three-dimensional arrays (collector, day, temperature) for each site under consideration for use in MINSUN. The results were then modified by applying the collector-array output-reduction factors from Table 2.8.
The collector-output integration program was originally written in Basic by Jim Hedstrom at LANL. The Basic program output was written onto magnetic tape and sent to Canada for use with the MINSUN program. This procedure did not allow users of MINSUN to adjust parameters of the collector models to fit national experience, so the collector code was translated from Basic to FORTRAN and integrated into the MINSUN preprocessor routine UMSORT by the Canadian 1(a) group. The FORTRAN listing of the computer program is Appendix A of this report.
