Abstract: An accurate measurement method based on thin wire thermocouple is proposed to solve the problem of lack of measurement method for freezing point temperature of test package in performance test of refrigeration appliances. By comparing the measurement results of platinum resistance and thermocouple, it is found that platinum resistance is easily disturbed by the environment because of its size, and the thin-wire thermocouple can significantly reduce the data deviation when it is arranged in the geometric center of the test package, which is more suitable for measuring the freezing point temperature. The method of determining the stable condition in the freezing process is clarified, and it is suggested that the stable condition of temperature fluctuation limit per unit time should be used to screen representative data, and the freezing point temperature should be obtained by calculating the average value. In addition, it is proposed to correct the measurement results based on the freezing point of pure water to eliminate the influence of equipment and environmental factors and ensure the comparability of cross-laboratory data. Experiments show that this method can effectively improve the accuracy of freezing point temperature of test packages, and provide technical support for standardization and reliability of refrigeration appliance testing.

Key words: Refrigerate, Test package, Testing method, Freezing point, Temperature correction