Method of Averages to Determine Insulation Conductivity under Transient Conditions

Abstract

A simple method of data analysis, called the averaging technique, is presented which may be useful in long-term field measurements of temperature dependent thermal conductivity of insulating materials. Its mathematical basis is the integral statement, which follows from the heat conduction equation For lin ear dependence of conductivity on temperature, on neglecting capacity terms, it yields simple algorithms to determine thermal conductivity in transient heat flow, for the weighted average temperature, when the heat flux and surface temperatures are measured simultaneously, and also when the heat flux comparator method is em ployed. The problem of proper control of the temperature inside the exposure test box, in order to minimize the error due to neglecting capacity terms, is discussed.