A procedure to predict solar receiver damage during transient conditions. (February 2022)

• Record Type: Journal Article
• Authors: Laporte-Azcué, M.; González-Gómez, P.A.; Rodríguez-Sánchez, M.R.; Santana, D.
• Is Part Of: Renewable & sustainable energy reviews. Volume 154(2022)
• Publication Date: 2022-02
• Subjects: External central receiver -- Creep-fatigue -- Lifetime -- Transient operation -- Clustered days; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2021.111905
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: The successful deployment of solar-power-towers lies in the reliable design of solar receivers, assuring the lifetime under high heat flux and cloud passages. Two main damage mechanisms appear during central-receiver operation: creep, during hold times at high temperatures and stresses, and fatigue, caused by transient operation. This work aims to determine the extent of each damage on a Haynes 230 receiver. It is analyzed using transient DNI of a whole year, controlling the operation to guarantee the receiver preheat and minimize the start-ups. The molten-salt flow-rate during cloud passages or hazy days remains as the clear-sky scheduled one, to avoid tube overheat, preventing salt degradation and stress reset, when the clouds cleared. The results show that creep dominates, with a minimum share of 73.8% for the transient case. High creep is motivated by the long operating (6 h per day on average), mostly at high DNI, while the low number of average start-ups per day (1.4) do not increase much the fatigue, barely affected by small transients. The use of clear-sky, instead of the transient DNI, constitutes a conservative estimation, with the creep greatly increasing, showing a minimum share of 82%. Consequently, the predicted lifetime is lower, going from 45 years to 27.8. Intermediate mass-flow control modes fall in-between them. Clustering the days according to their DNI features shows that the high-energy days, with high creep, are the most common, highlighting the creep interest and that the fatigue can be estimated taking only the strain range produced by the start-up. Highlights: Fine fatigue cycle counting considering cloud passages using rainflow method. Maximum fatigue damage in the receiver around 27%, at the salt inlet panels. Fatigue damage mainly due to the startups. Low influence of small cloud passages. Long hold times at high temperature and stress cause the most damage due to creep. Clear-sky DNI model is reasonable for a first and conservative lifetime estimation.