-- This project is inactive --

The University of Arizona, along with partners at Arizona State University and Georgia Institute of Technology, under the 2012 Multidisciplinary University Research Initiative (MURI): High Operating Temperature (HOT) Fluids funding opportunity, is investigating the use of halide salts with oxyhalide additives as a heat transfer fluid (HTF) in concentrating solar power (CSP) systems operating at temperatures greater than 800°C. By allowing higher temperature operation, CSP systems can achieve greater efficiencies and thereby reduce the overall system cost.


The research team is investigating mixtures of covalently and ionically bonded halide salts with additives such as oxyhalides. The goal of this project is to discover a salt mixture with the following properties:

  • A freezing point below 250°C
  • Stability at temperatures greater than 800°C
  • Low corrosion of stainless steel and high-nickel content alloys
  • A cost of less than $1/kg.


The mixture of salts with two different bond types increases disorder in the system, thereby increasing the liquidus range of the salt mixture. The research team is modifying the thermophysical properties of the mixture by introducing Lewis acid/base additives (leading to a generalization of Bronsted acid/base interactions) and/or network forming additives. This allows for the simultaneous tuning of the thermodynamics and transport properties of the HTF in order to meet the needs of a CSP system.

The SunShot CSP R&D program seeks to accelerate progress toward the cost target of $0.06 per kilowatt-hour through novel and revolutionary research into CSP technologies. Learn about other concentrating solar power research.