2014 年 31 巻 2 号 p. 237-244
Secondary refrigerants have been used in various indirect heat pump and refrigeration systems. The fundamental properties of potassium formate aqueous solutions are a key component of these refrigerants. We have investigated the fundamental properties of potassium formate aqueous solutions, such as refractive index, density, specific heat and viscosity. The measurements of fundamental properties were performed in the concentration range varied from 0.0 to 50.0 wt% for measurements of refractive index, density and specific heat, 10.0 to 50.0 wt% for viscosity, while the temperature range varied from 5 to 50 oC for measurements of refractive index and specific heat, 0 to 70 oC for density and 0 to 50 oC for viscosity. The results indicate that the measured properties increase with solution concentration and decrease with increasing solution temperature except for specific heat. In addition, the empirical equations of these properties are presented and are in good agreement with experimental results.