Heat transport characteristics of a peak shaving solar power tower station

Abstract

The study investigates the heat transport characteristics of the solar power tower station with thermal energy storage, which serves as a peak regulation source in the grid. A 50 MW power tower plant is chosen as object. The systematic dynamic models of essential sub-systems are developed. The model is matched with control strategy that regulates the water level in the evaporator efficiently. System-level simulation is conducted under different disturbances. For a short period disturbance, the thermal transport characteristics of system parameters during the heat transport process under four-step disturbances have been analyzed. Variation of heat distribution among different heat exchangers and instability of water level are discovered. The steam generating system has significant thermal inertia compared with that of steam turbine. For a long period of disturbance, the peak shaving characteristic curve of the plant operated under peak regulation mode is presented. It takes 1 h to load-up and 2 h to off-load between the basic load and designed load. Dangerous working condition is found during offload. The impact of different ramp rates is revealed. PID control strategy is more sensitive to an 8% ramp rate. The results could provide references for peak regulation capacity of a solar power tower station.