Heat transfer oil expansion tank

Select the heat transfer oil based on the local minimum temperature. Alkylbenzene-type (benzene-ring type) heat transfer oils: These types of heat transfer oils are compounds in which a benzene ring is attached to alkane side chains; they are products resulting from the combination of short-chain alkyl groups (including methyl, ethyl, and isopropyl) with the benzene ring. Its boiling point is between 170–180°C, and its freezing point is below -80°C; therefore, it can be used as an antifreeze. The advantage of such products is that they do not tend to form precipitates within their suitable operating range, with compounds containing isopropyl side chains being particularly good for this purpose. Alkyl biphenyl ether-type heat transfer oils are isomeric mixtures in which two benzene rings are connected by an ether link, with two methyl groups attached to each benzene ring. Such mixed heat transfer oils have a low dynamic viscosity at low temperatures and good fluidity, making them suitable for use in cold regions in the north. The recommended operating temperature should not exceed 330°C, while the freezing point is -54°C. Their service life is better than that of mineral oil and alkylbenzene-type heat transfer oils. The most common type worldwide is the xylene ether-type heat transfer oil, and there are also manufacturers in China that produce such high-temperature heat transfer oils.