Analysis of a Concentrating Solar Power Tower Operating with a Closed Joule Brayton Cycle and Thermal Storage

In this paper, a solar tower power plant with a closed Joule-Brayton cycle, of 5 MW rate power, with molten salts thermal storage, located in Seville is presented. The peculiarity of the cycle, using air like fluid work, is to vary, by an auxiliary compressor and a vent valve, the pressure, so that fluid average density, at gas turbine inlet. An adjustment of the mass flow rate, in order to regulate the exit air temperature from the receiver of concentrating solar tower, is obtained. During energy surplus production, the thermal storage energy is loaded. Particular attention is placed to the energy thermal storage, which uses molten salt KCl-MgCl2, suitable for this application due to its high melting temperature, in double tank configuration. The thermodynamic model of the entire plant was implemented using Thermoflex® software, while, for the concentrating tower, WinDelsol software was used. Using time data relating to the locations, the performance of the entire plant, during a year, has been simulated. Preliminary results show that this plant can achieve relevant benefits in total energy production and equivalent operation hours per year, therefore it is competitive with conventional energy production systems. Furthermore, a performances estimation with a cost analysis, using a LCOE parametric analysis, has been performed.