System Design of a 2.0 MWth Sodium/Molten Salt Pilot System

Kenneth Armijo, Matthew Carlson, Dwight Dorsey, Joshua Christian, Craig Turchi

Research output: Contribution to conferencePaperpeer-review

2 Scopus Citations


Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. Although slightly higher limits may be possible with molten salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, HTF technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative to molten salts, such as with alkali metal systems. This investigation explores the development of a 2.0 MWth sodium receiver system that employs a sodium receiver as the HTF, as well as with a ternary chloride (20%NaCl/40%MgCl/40%KCl by mol wt.%) salt as a thermal energy storage (TES) medium to facilitate a 6-hr. storage duration. A sodium-to-salt heat exchanger model as well as a salt-to-sCO2 primary heat exchanger model are employed and evaluated in this investigation. A thermodynamic system design model was developed using Engineering Equation Solver (EES) where state properties were calculated at inlets and outlets along both hot and cold legs of the pilot-scale plant. This investigation assesses receiver performance as well as system efficiency studies for the pump and system operational ranges. Results found that high efficiency sodium receivers were found to have higher heat transfer coefficients and required far less spreading of incident flux. The system performance model results suggest that for a pump speed of 2400 RPM, respective hot and cold pump TDH values were determined to be 260.1-307 ft. and 260.1-307 ft for pump flow rates of 90-120 GPM.

Original languageAmerican English
Number of pages7
StatePublished - 2020
EventASME 2020 14th International Conference on Energy Sustainability, ES 2020 - Virtual, Online
Duration: 17 Jun 202018 Jun 2020


ConferenceASME 2020 14th International Conference on Energy Sustainability, ES 2020
CityVirtual, Online

Bibliographical note

Publisher Copyright:
Copyright © 2020 ASME

NREL Publication Number

  • NREL/CP-5700-76070


  • CSP
  • heat transfer fluids
  • nitrate molten salt concentrating solar power
  • sodium receiver system
  • solar
  • thermal energy storage


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