U.S. Department of Energy

Polyaromatic Naphthalene Derivatives as Solar Heat Transfer Fluids

Oak Ridge National Laboratory logo Photo of a lab with silver metal pipes, frames, and canisters connected together.

Oak Ridge National Laboratory built a high-temperature loop to test a substituted naphthalene synthetic oil to temperatures exceeding 500°C.

Oak Ridge National Laboratory, under an ARRA CSP Award, is addressing the need for heat transfer fluids (HTFs) for solar power generation that are stable to temperatures approaching 600°C, have good thermal characteristics, and do not react with the vessels in which they are contained.


The research team is working to demonstrate the possibility of using substituted polyaromatic hydrocarbons for a solar heat transport application, which has not yet been considered because of the scarcity of thermophysical data on these compounds. The candidate fluids are expected to have thermophysical properties and stabilities up to and above 500°C, and should be readily available as the byproducts of clean-diesel refining. The fluids are being evaluated by:

  • Optimizing the chemistry and thermophysical properties of candidate HTFs based on these materials for repetitive cycling to high temperatures
  • Testing performance of the HTFs in an instrumented laboratory
  • Testing performance in a pilot-scale concentrating solar loop at Cool Energy.

If successful, the results from this project will provide an option for parabolic and Fresnel solar collectors for power generation at temperatures above 500°C.


Low vapor pressure and resistance to thermal decomposition may make phenylnaphthalenes and similar polyaromatic hydrocarbons suitable for heat transfer applications involving parabolic solar collectors. In particular, 1-phenylnaphthalene has an advantage over high-temperature inorganic salts for applications up to 530°C because it is a liquid at room temperature.

Publications, Patents, and Awards

At this time, this project does not have published articles, patents, or awards.

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CSP Program Overview

Learn about other DOE competitive awards for concentrating solar power research that are in progress.