Analysis of Heat Transfer of Molten Salts Startup Flow in Cold Pipes Avoiding Freezing in Solar and Nuclear Energy Systems

Ye Zhang, Fouad Haddad, Peiwen Li

Research output: Contribution to journalArticlepeer-review

Abstract

Molten salts are employed as the heat transfer fluid to carry the thermal energy from a solar receiver or a nuclear reactor for delivering to thermal storage systems or thermal power plants for power generation. For the startup operation, molten salts need to be pumped to flow into the pipes which may have lower temperature than the freezing point of molten salt due to the cold ambient temperature overnight or over the suspension of operation. Preventing the freezing of molten salt in cold pipes becomes a critical issue to the safe operation of a concentrating solar thermal power plant or a molten salt nuclear power plant. This study conducted a basic heat transfer analysis of the transient heat transfer from flowing molten salt to a cold pipe to determine the length from entrance to the onset of freezing of the fluid. From our modeling and analytical solution using method of characteristics, the correlation of the location of onset of freezing of molten salt with respect to the flow velocity, heat capacities of molten salt and pipes, dimension of the pipes, and the initial temperatures of salts and pipes, have been understood clearly. The modeling and computational tool can fundamentally help engineers to design a system to avoid freezing and clogging at cold startup when molten salt is applied as a heat transfer fluid.

Original languageEnglish (US)
Article number011002
JournalJournal of Solar Energy Engineering, Transactions of the ASME
Volume147
Issue number1
DOIs
StatePublished - Feb 1 2025

Keywords

  • cold startup
  • critical length of onset of freezing
  • flow in pipe
  • heat transfer modeling analysis
  • molten salt freezing
  • solar
  • thermal power

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology

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