A novel method of accurately characterizing heat pipes using thermoelectric modules

This study details an experimental method for the accurate and rapid thermal characterization of lowintermediate temperature heat pipes (<200 C-degrees). The aim of this work was to provide a method of measuring the thermophysical characteristics of heat pipes while providing definitive uncertainty values that enable accurate performance estimations prior to implementation into electronic systems. To achieve this, the apparatus used two heat flow meters, constituting cubic copper interface blocks and thermoelectric modules that measured heat flow rates across the specimen while precise, well-calibrated (+/- 0.01 K) thermistors measured axial temperature drops along its length. The method was first demonstrated by characterizing a cylindrical copper reference specimen of known thermal conductivity, indicating a high degree of accuracy, with measured effective thermal conductivity values within +/- 2 % of the correlated value. Concerning the thermal characterization of heat pipe specimens, thermal resistances and corresponding effective thermal conductivities of 0.122-0.08 K/W and 61.8-90.8 kW/m.K were measured for heat flow rates between 5 and 30 W. Uncertainties within the derived characteristics were less than 3.2 % for low heat flow rates (5-15 W) and less than 1.3 % for higher heat flow rates (15-30 W). Moreover, a 450 % reduction in characterization time was achieved compared to methods that employ thermally massive heat flow meters. In many aspects, the presented method achieved superior performance compared to those presented within the literature, proving its effectiveness for the accurate characterization and subsequent implementation of heat pipes into electronic systems.