Keywords

thermocline tank, thermal energy, storage

Abstract

A thermocline tank is a low-cost thermal energy storage subsystem for concentrating solar power plants that typically utilizes molten salt and quartzite rock as storage media. Longterm thermal stability of the storage concept remains a design concern. A new model is developed to provide comprehensive simulation of thermocline tank operation at low computational cost, addressing deficiencies with previous models in the literature. The proposed model is then incorporated into a system-level model of a 100 MWe power tower plant to investigate storage performance during long-term operation. Solar irradiance data, taken from measurements for the year 1977 near Barstow, CA, are used as inputs to the simulation. The heliostat field and solar receiver are designed with DELSOL, while the transient receiver performance is simulated with SOLERGY. A meteorological year of plant simulation with a sixhour capacity for the thermocline tank storage yields an annual plant capacity factor of 0.531. The effectiveness of the thermocline tank at storing and delivering heat is sustained above 99% throughout the year, indicating that thermal stratification inside the tank is successfully maintained under realistic operating conditions. Despite its good thermal performance, structural stability of the thermocline tank remains a concern due to the large thermal expansion of the internal quartzite rock at elevated molten-salt temperatures, and requires further investigation.

Original Publication Citation

Flueckiger, S. M., Iverson, B. D., Garimella, S. V., and Pacheco, J. E., 2014, "System-level simulation of a solar power tower plant with thermocline thermal energy storage," Applied Energy, Vol. 113, pp. 86-96. doi:10.1016/j.apenergy.2013.07.004

Document Type

Peer-Reviewed Article

Publication Date

2014

Permanent URL

http://hdl.lib.byu.edu/1877/3482

Publisher

Applied Energy

Language

English

College

Ira A. Fulton College of Engineering and Technology

Department

Mechanical Engineering

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