Thermally conductive nanoparticles are often added to conventional fluids to improve thermal properties. In this paper, the effect of small concentrations of multiwalled carbon nanotubes (MWCNTs) on thermal conductivity over a range of temperatures was tested. A Thermal Constant Analyser measured the thermal conductivity of the nanofluids with the transient plane source (TPS) method from 10 to 80 °C. Results showed that thermal conductivity of the nanofluids increased with temperature, and with ...