CIEMAT Publications

Abstract

Direct steam generation in parabolic-trough collectors is one of the most promising technologies for electricity production from renewable sources. However, it still presents several challenges and uncertainties that should be analyzed thoroughly by means of suitable simulation tools.

In this work a quasi-dynamic simulation model is defined and developed in the TRNSYS software that is able to address dynamic conditions such as start-up, shutdown and solar transients accurately and with limited computational resources. The model has been validated with real data from an experimental installation and an analogous steady-state simulation model has been defined to assess the annual results of a whole plant. In this study a 5 MWe solar thermal power plant with direct steam generation in parabolic troughs is described and dimensioned. The solar plant TRNSYS model includes both the solar field and the power block for each of the approaches mentioned, quasi-dynamic and steady-state. The results of the annual simulation demonstrate that important differences appear between both models that should be taken into consideration when predicting yearly plant production. The results obtained are also applied to perform a basic economic analysis that is useful to determine the effect of these discrepancies in terms of electricity costs.