Analysis and optimization the size of heliostat field and thermal energy storage for solar tower power plants

The optimal sizing of solar tower power (STP) plants with thermal energy storage (TES) is critical for increasing the system reliability and reducing the investment cost. However, it is still unclear to determine the key design parameters for sizing the STP system, including design direct normal irradiance (DNI), solar multiple (SM) and TES hours. In this study, a thermo-economic analysis of the effects of these parameters on the capacity factor and levelized cost of energy (LCOE) of a 50 MW STP plant is presented using System Advisor Model. Optimal combinations of these parameters are obtained with respect to the minimal LCOE at two locations in China The results show that the optimal design DNI is dependent on both the annual radiation level and the distribution of solar irradiance, which differs from the recommended values obtained from traditional methods. It is found that the irradiation received by heliostats at the optimal design condition accounts for a specific percentage of annual irradiation. The percentage is close to 73% for the cases in this study, and the corresponding optimal SM and TES hours are 2.7-2.8 and 15-16 hours respectively. The results can provide a theoretical reference for the optimal sizing of STP with TES systems under different solar resources. (C) 2019 The Authors. Published by Elsevier Ltd.