INFLUENCE OF THE MEAN VOLUMETRIC TEMPERATURE OF A THERMOELEMENT ON RELIABILITY INDICATORS AND THE DYNAMICS OF A COOLER

The paper deals with the influence of the mean volumetric temperature of a thermo-element branch on the basic parameters, reliability indicators and the dynamics of operation of thermo-electric cooler under different temperature changes at the assigned heat load, geometry of branches of thermo-elements for specific current operation modes. It was shown that the mean temperature of the thermo-element, which is a reference point when calculating the energy performance of the thermoelectric cooler, can be used only for calculations in the stationary operation mode. Its use in the dynamic mode leads to significant errors. It was proven that the mean volumetric temperature of a thermo-electric branch can be such a reference point for a dynamic mode. The ratio for assessment of the mean volumetric temperature depending on the relative operating current was determined. The relationships between the mean volumetric temperature of a thermo-element, the time required to enter a stationary mode, the required number of thermo-elements, the differences between the mean volumetric and the mean temperature, and a cooling coefficient, depending on the relative working current, were analyzed. It was shown that at an increase in the mean volumetric temperature at the assigned current operation mode and a temperature difference, exceeding 40K, the magnitude of operating current, the number of thermo-elements, consumption power, failure rate and time constant decrease and cooling factor increases. The time for entering a stationary mode during the transition from the mode of minimum failure rate to the mode of maximum cooling capacity decreases by 5 %, while the failure rate increases by 16 %. The practical significance of the conducted research is both to improve the quality of design of coolers and to select the necessary modes of thermo-electric system for ensuring thermal modes of electronic equipment depending on the importance of dynamic or reliability criteria of contro