Transient Characterization of Multiple Parabolic Trough Collector Loops in a 100 MW CSP Plant for Solar Energy Harvesting

Parabolic trough solar collection technology has been widely deployed in concentrated solar power (CSP) generation plants all over the world. In a large-scale CSP plant, a solar field consists of hundreds of parabolic solar collector loops. Due to the parallel loop arrangement (Fig. 1) and non-unifoum solar collection, mal-distributions of heat-transfer-fluid flow (HTF, synthetic oil) among different loops commonly occur during transient operation. Many solar collector loops have to be pushed out of tracking phase to avoid oil overheating and degradation, which causes significant loss in solar energy collection and power generation. Such collector defocusing and refocusing operation results in large transient variation of HTF temperature, which further brings challenges to energy-efficient operation and maintenance of the coupled thermal power generation unit. Advanced transient analysis, control and fault diagnosis tools are desired to achieve safer CSP plant operation and transient solar power harvesting. In this paper, a distributed transient optical-thermal-fluid model of parabolic trough collector is developed and validated with field data from a 100MWth CSP plant. Transient model predictions are in fair agreement with experimental field data, which provide a quantitative tool for solar energy harvesting. Conceptual active flow control strategies are further introduced to regulate the HTF temperature and maintain high solar collection efficiency.