Solar Variability and Thermal Inertia in Small CSP Plants
Abstract
Concentrated Solar Power (CSP) plants convert solar energy into thermal energy through collector mirrors that concentrate solar radiation onto a working fluid, which transfers the heat to a power cycle. These plants are modeled considering two main subsystems: the solar field, responsible for capturing and transferring thermal energy, and the power cycle, responsible for converting this energy into electricity. This study analyzes solar variability and thermal inertia in a small-scale CSP plant operating with and without a thermal energy storage (TES) system under irradiance conditions typical of Florianópolis and Brasília. The solar field employs parabolic collectors and Thermisk as the heat transfer fluid, while the thermal energy storage system uses Syltherm™ XLT in sensible heat operation. The implemented power cycle was a simple Organic Rankine Cycle (ORC) operating with the R152a refrigerant. Summer and winter conditions were simulated based on direct normal irradiance (DNI) data obtained from the SONDA solar measurement network. The results indicate that the presence of TES increases the stability and continuity of generation, reducing the plant’s sensitivity to DNI fluctuations. Additionally, thermal storage was found to contribute to higher operational reliability and better utilization of solar resource in small-scale CSP plants.
Keywords
Concentrated Solar Power, Thermal Energy Storage, Organic Rankine Cycle, Solar Variability, Thermal Inertia