Thermal Insulation for a High Temperature Molten Salt Storage Tank in a CSP Plant: Paper No. 190027

Soheila Riahi, Ming Liu, Rhys Jacob, Martin Belusko, Craig Turchi, Frank Bruno

Research output: Contribution to conferencePaper

1 Scopus Citations

Abstract

A ternary molten chloride has been suggested as a high temperature (550-720 °C) sensible heat storage medium for a two-tank system. An effective thermal insulation is proposed to provide an opportunity for the fabrication of both the hot and cold storage tanks from lower cost metals, e.g. A240-347H, by maintaining the tank wall below 500 °C. To achieve this, the hot storage tank mainly comprises of inner shell (11.4 cm of a refractory brick as liner (KX-99®), 30 cm of insulation brick) and outer metal shell, where 5 cm of frozen layer of PCM800 (NaCl), and 5 cm of ceramic wool fill the annular space between the shells. Another layer of ceramic wool was introduced at the outer side of the metal shell to keep the temperature lower than 60 °C. ANSYS Fluent was used for the numerical study of the cool down behavior of the system during idle period when tank is quarter-filled. The heat transfer modes were considered as radiation and natural convection heat transfer from the hot molten salt at 720 °C, conduction through the solid layers and convection heat transfer from the outer shell to the environment at 15 °C. The results showed that the proposed insulation system including a frozen layer of PCM800 maintains the temperature at the metal wall lower than 500 °C, and lower than 60°C at the outer side of the tank. Apart from the insulation property of the frozen layer of PCM800, it absorbs any leak of hot molten salt, acting as a barrier between salt and the metal shell. The thermal performance analysis provide an insight into the benefits of the multilayer insulation.
Original languageAmerican English
Number of pages7
DOIs
StatePublished - 2020
EventSolarPACES 2019: International Conference on Concentrating Solar Power and Chemical Energy Systems - Daegu, South Korea
Duration: 1 Oct 20194 Oct 2019

Conference

ConferenceSolarPACES 2019: International Conference on Concentrating Solar Power and Chemical Energy Systems
CityDaegu, South Korea
Period1/10/194/10/19

Bibliographical note

See NREL/CP-5700-77910 for preprint

NREL Publication Number

  • NREL/CP-5700-78859

Keywords

  • CSP
  • molten salt
  • solar
  • storage

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