Parabolic trough field control utilizing all sky imager irradiance data – A comprehensive robustness analysis

Abstract

Parabolic trough (PT) power plants focus the sun's irradiation onto an absorber tube using collector mirrors to increase the temperature of the heat transfer medium (HTF). In the power plant, the HTF is used to generate electricity. To heat up the HTF, PT solar fields are set up in large areas and pipes are used to distribute the HTF in the solar field. The control system adjusts the temperature by changing the mass flow into the solar field and the focusing of the individual collectors. Transient conditions such as cloud passage are the main challenge for the system. State of the art control schemes use information from a few irradiation measuring points in the solar field. These measurement points are precise for the individual location but cannot accurately represent the irradiation situation in the whole solar field. In this paper, a control system that uses spatially resolved irradiation information from all sky imager systems is investigated.First, the control system was developed and tested in various simulation runs under ideal conditions. The focus of this work is to investigate the robustness of the control concept under non-ideal conditions. For this purpose, the simulation conditions are adapted to real situations and the behavior of the control system is analyzed.A robust behavior of the control system is shown in the simulations under different non-ideal scenarios. Overall, an improvement in electrical yield of 1.4% can be achieved compared to a reference without access to spatially resolved irradiance data.