Report of a ranked state of art review about HTF/HSM materials

The objective of this work is to improve the quality of performances and procedures regarding laboratory studies, and to summarize and make available the presented or investigated data about the main characteristics of each feasible HTF (heat thermal fluid)/HSM
(heat storage material) for CSP (concentrating solas power) applications. The first necessary step for this work development is to collect and classify, according to shared evaluation criteria, the currently available fluids feasible to be used as HTF and/or HSM.
The following materials are taken into account

1. Alkaline/alkaline earth metals nitrate/nitrite mixtures
2. Thermal oils
3. Solid Media Storage Technology (as HSM)
4. PCM (phase change materials) (as HSM)
5. Gas/steam (as HTF, pressurized liquid water also proposed for buffer storage systems)
6. Liquid metals
7. Nanoparticles materials (nanoparticles additivate to HTF/HSM)
8. Thermochemical heat storage

The following characteristics have been considered for the rating

1. Environmental safety
2. Risk for human health
3. Freezing temperature
4. Upper thermal stability point
5. Thermo-physical properties (density, viscosity, heat capacity, thermal conductivity)
6. Construction materials compatibility
7. Material cost
8. Cost of handling equipment and system
9. Efficiency of the power block associated (for HSM)

The obtained results are reported and discussed.