Simplified analysis of relation between the type of enclosure and temperature coefficient of output signal of thermal converters

The output signal of the thermal converter should be insensitive to ambient temperature changes. In practice, however, a thermal converter always features a nonzero temperature coefficient of the output signal. This coefficient is determined mainly by the dependence of the heat transfer process on the ambient temperature. The main goal of this paper is to analyze the effect of different enclosures on particular and total temperature coefficients. Three types of enclosure are considered: high-volume enclosure filled with a gas at pressure close to the atmospheric, low-volume enclosure filled with a gas at pressure close to the atmospheric and low-volume partially evacuated enclosure at internal pressure of some 1-10^-4 Pa. The analytical expressions for both the thermal conductances and their corresponding temperature coefficients are presented. Example numerical results for a prototype of the converter are also included.