Optimized Mirror Cleaning Strategies in PTC Plants Reducing the Water Consumption and the Levelized Cost of Cleaning

Soiling reduces the optical efficiency of the reflectors in a CSP plant and thus has a negative effect on the plant power output and LCOE. To mitigate this effect, regular cleaning should be performed which in turn increases the operation cost and consumes large amounts of water. In this study, potential improved cleaning strategies were tested through detailed dynamic simulation with an attempt to realize the relation between the cleaning water consumption and the specific cost of cleaning as well as to identify the optimum cleaning strategy for a specific site answering the question when and which collector should be cleaned. The aim of the study is to evaluate different cleaning strategies through a CSP performance model which is able to simulate the behavior of a CSP plant as close as possible to the real conditions. For this reason, spatiotemporal distribution of cleanliness in the solar field and individual loop simulation were taken into account in order to consider the effect of the non-homogenous cleanliness on the outlet temperature of the solar field. Additionally, the cleaning processes have been modelled based on the characteristics of ECILIMP cleaning trucks obtained from several on-site and laboratory scale tests. The simulation results show that the proposed cleaning strategy with variable threshold can reduce the cleaning water consumption by up to 19% and reduce the levelized cost of cleaning by 25% without any negative effect on the plant performance.