Design and research of calibration device for specific heat capacity of refrigerator test package

In the refrigerator performance test, the test package is used to simulate the load in the refrigerator, and the national standard has clear requirements for its size and quality, but the thermal performance is only stipulated as "equivalent to lean beef", lacking specific quantitative indicators. After long-term use, the thermal performance of the test package may change, which will affect the accuracy of the refrigerator performance test. In order to quantify the change of thermal performance of test package, a calibration device for specific heat capacity is designed in this paper. The device adopts the Dewar bottle structure combining vacuum layer and constant temperature layer, which effectively solves the problem of temperature stability of the measuring chamber under low temperature environment of -18℃, and the heat leakage rate is reduced to 0.02℃/h, which is better than the traditional device's 0.05℃/h. The experimental results show that the single measurement standard deviation of the device is 0.03 kJ/(kg•K), and the load simulation error of the calibrated test package is reduced from ±3.2% to ±1.1%. The device has a high degree of automation, and the measurement efficiency is increased by about 30%. It provides a reliable calibration means for refrigerator performance test, and has a wide application prospect in cold chain logistics and low temperature material research.