Cesium and ammonium salts as low temperature secondary fluids

Potassium formate and potassium acetate, as well as their blends are known as environmentally friendly secondary fluids with good thermophysical properties. The aim of this work was to investigate properties of cesium formate, cesium acetate and ammonium acetate solutions. Results showed that various alkali metal ions such as potassium, sodium, cesium or ammonium are affecting the freezing point, thermal conductivity, viscosity and specific heat capacity in different ways. Among examined salts, ammonium formate showed the best performance by giving the highest specific heat capacity and highest thermal conductivity and the lowest dynamic viscosity compared to potassium formate and other salts. Cesium formate solutions had the lowest viscosity among all tested salts. This study shows that both cesium formate and sodium formate could be used as different additives to enhance different properties of potassium formate and potassium acetate secondary based fluids.