Estimation of Freezing Point of Ternary Coolant Mixture

Aqueous glycol solutions are widely used as coolant in secondary refrigeration systems. Freezing point is one of the crucial properties used to characterize the performance of coolant. Instrumental methods are often complex and require expensive equipment. For selection of right coolant mixture there was a need for systematic study of aqueous-glycol-salt solution over a wide range of composition. The research work in this paper presents a novel and rapid way for freezing point characterization of the ternary coolant mixture. The freezing behavior of ternary mixture was studied for different blends of ethylene glycol (EG), propylene glycol (PG), sodium chloride (NaCl) and water. Two sets of ternary mixture TM1 (EG-NaCl-water) and TM2 (PG-NaCl-water) were evaluated experimentally at various concentrations of glycol and NaCl. Effect of glycol and salt concentration on freezing point depression was analyzed. The results demonstrated that ternary mixtures required less EG/PG for cost effective formulation of secondary coolant for different cooling application in dairy and food processing industry.