Investigation of using molten salt as heat transfer fluid for dry cooled solar parabolic trough power plants under desert conditions

5 years ago

Investigation of using molten salt as heat transfer fluid for dry cooled solar parabolic trough power plants under desert conditions

This research aims mainly at further investigate technical options to reduce the cost of electric power production from concentrating solar power plants in hot arid regions. The work also aims to minimize water consumption due to its scarcity in such regions by means of investigating the utilization of dry cooling option. However, dry cooling system increases the parasitic power consumption of the power plant and this is bound to reduce the overall system efficiency. In arid regions, this loss in efficiency is compensated by the abundance of solar radiation that results in a better solar field efficiency. Furthermore, this study investigates the effect of using alternative heat transfer fluid in the solar circuit instead of synthetic oil. For this purpose, an optimization of a solar parabolic trough power plant coupled with dry cooling system has been performed using the simulation software “SAM”. The optimization is carried out by varying the solar field size, the thermal energy storage system, the size of the power block (steam turbine) and the type of the heat transfer fluid. This was done in order to find out the best combination that gives lowest power production cost. The power plant was simulated in two steps with different combinations; while “Therminol VP I” was used in the first step, as heat transfer fluid, in the second step, “Therminol VPI” was replaced by “Molten Salt”. The obtained results prove that plants with large solar fields (solar multiple of 2) and large thermal energy storage systems (7.5 full load hours) perform better and can generate power at lower costs compared with smaller plants. The investigation of alternative heat transfer fluid shows that molten salt is more cost effective than synthetic oil in parabolic trough power plants. The obtained Levelized Cost Of Electricity of the best power plant optimized configuration is 17.24 c€/kWhe and 13.8 c€/kWhe, for plants with “Therminol VP I” and “Molten Salt” as heat transfer fluid, respectively. The optimization results with “Molten Salt” as heat transfer fluid show excellent results regarding the dry cooled solar power plants. This show good technical and economic potentials in future designs.

Publisher URL: www.sciencedirect.com/science

DOI: S0196890417310300