Thermal stability of organic fluids for Organic Rankine Cycles systems

Each organic fluid is characterized by important thermal decomposition above a specific temperature called thermal stability limit. The correct evaluation of this limit is extremely important to avoid massive cracking phenomena which cause fouling of heat exchangers surfaces, material erosion and changes of fluid thermodynamic properties. After a brief discussion about the mutual correlation between the chemical structure and the thermal stability of working fluids, a review of the main experimental data available is worked out. Finally, an experimental apparatus and a useful methodology to determine limit temperatures for the working fluids is presented and discussed.