Entwicklung eines Einsatz- und Betriebsoptimierers für ein hybrides Kühlsystem mit kältespeicher zur Wassereinsparung und Ertragssteigerung in einem CSP-Kraftwerk

Kurzfassung

Water consumption becomes a continously increasing issue in the design and operation process of concentrated solar power plants. If a conventional wet cooling tower is used, the cooling system has the largest share of water consumption. By utilizing a dry cooling system instead, water consumption can be decreased by over 90 %. In return, operating and maintenance costs increase while the thermal efficiency is reduced. Hybrid cooling systems aim at a tradeoff between water consumption and efficiency by combining at least two cooling mechanisms in one or more components. Due to the increasing complexity of the systems a demand for optimized operation plans emerges. This thesis attemps to solve the problem by introducing a distpatch and operation optimizer for hybrid cooling systems aiming to maximize the power generation, while minimizing water consumption at the same time. The value of water can be adjusted, so that higher water savings can be achieved at the costs of reduced electrical yield. The cooling optimizer is designed to optimize operational plans over a finite time horizon up to 24 h. It can be applied for online-optimization in a real power plant or to investigate cooling systems theoretically. The latter can be achieved by utilizing the optimizer in yield assessment calcualtions. One major advantage of the solution, proposed in this thesis, is that the cooling optimizer is independent of the CSP-Plant and hybrid cooling system, meaning that the solution can be applied to arbitrary power plant configurations and cooling systems without adjusting the solution algorithm. The only requirement is that a model of the plant and cooling system is available to the optimizer, such that the performance of the optimizer can be customized by setting corresponding parameters. The viability of the developed algorithm is demonstrated by implementing a testbench including the cooling operation optimizer into a simulation tool for yield assesment calculations (YACOP) and investigating a 50 MW parabolic trough power plant with different hybrid cooling systems. To evaluate the performance of the optimizer, two hybrid cooling systems both equipped with a cold thermal energy storage have been designed and analyzed within the scope of this thesis. It has been determined, that the application of a cold thermal energy storage in parallel to a dry cooling component is energetically reasonable. The application in parallel to a wet cooling tower aims at a decrease in water consumption. Depending on the cooling components and the value of water given to the optimizer, water consumption can be decreased and eletricity generation can be increased. However, water consumption always comes at the costs of reduced electrical yield, which can partly be compensated by applying the cooling operation optimizer. Economical investigations can be executed as a post processing step in YACOP after applying the simulation with optimization of the cooling operation plans, when information on investment, operation and maintenance costs are at hand.