Thermophysical Properties of LiNO3–NaNO3–KNO3 Mixtures for Use in Concentrated Solar Power

Abstract

One of the major challenges preventing the concentrated solar power (CSP) industry from occupying a greater portion of the world's energy portfolio are unattractive start up and operating costs for developers and investors. In order to overcome these reservations, plant designers must be able to achieve greater efficiencies of power production. Molten salt nitrates are ideal candidates for CSP heat transfer fluids and have been proposed to offer significant performance advantages over current silicone based oil heat transfer fluids. Ternary molten salt nitrates offer high operating temperatures while maintaining low freezing temperatures. However, a shortage of important thermophysical property data exists for these salts. Previous work has shown the ternary compositions of LiNO3–NaNO3–KNO3 salts offer the widest possible temperature range for use in a CSP system. The present work contains data for the viscosity, specific heat, and latent heat of some mixtures of these salts at various temperatures, providing vital information for plant designers to optimize power generation and attract future investment to CSP systems.