The Operating Strategy and Its Impact on the Performance of a 30 MWe SEGS Plant

Abstract

The part-load behavior of a typical 30 MWe SEGS plant was studied using the detailed thermodynamic model EASY. In this model, a detailed solar field model was directly included, which was based on measurement results of an LS-2 collector and accounts for various conditions of receiver tubes, lost mirrors, and measured reflectivity. For the first time, the overall plant performance of a solar electric generating system could he compared with this tool, and the influence of changing operating conditions could be analyzed. Both, the solar field and the complex EASY model were first compared to measured plant data. This showed that, although the results of the solar field model agreed quite well with test loop data, there are still little differences between the plant model results and real plant conditions. Finally, the effects of different plant operating strategies were studied for summer, fall, and winter days. This clearly demonstrates that, depending on the insolation conditions, different superheating temperatures should be chosen to maximize the net output. With a reduced solar field pressure drop due to using rotating joints in the field, the lowest possible superheating temperature maximizes the net output in any case.