Abstract:

In this paper, refrigerant liquids containing three or four components such as ethanol, propylene glycol, salt and water were prepared, and the relationship between the freezing points and the components of the refrigerant liquids were analyzed via the temperature-time method. Then, the impregnation of the refrigerant liquids in gelatin gel model was investigated by means of the silver nitrate titration and the gas chromatography. The results indicate that （ 1 ） when the mass fraction of the solutes is larger than 45 %, the ternary refrigerant liquid consisting of ethanol, propylene glycol and water is of a freezing point lower than that of the ethanol solution with the same solute mass fraction, especially at a ethanol mass fraction varying from 20% to 30% ; （2） NaCl has the greatest effect on the decrease of the freezing point of the quaternary refrigerant liquid ; and （3） as compared with the common salt or ethanol solutions, the quaternary refrigerant liquid consisting of ethanol, propylene glycol, sodium chloride and water is of the lowest solute impregnation capacity. Thus, it is concluded that the quaternary regrigerant liquid is more suitable for immersion chilling and freezing due to its low freezing point, solute mass fraction and impregnation capacity.

Key words: immersion chilling and freezing, refrigerant liquid, freezing point, impregnation