Incorporation of tungsten trioxide (WO3) nanoparticles into ethylene glycol (EG) was performed to examine the nanoparticles presence on thermal conductivity behavior. To explore the mass fraction and temperature efficacy on the amount of thermal conductivity enhancement, many samples were produced at 0.005, 0.01, 0.05, 0.1, 0.5, 1,5 wt% and conductivity measurements were performed at 5-65 degrees C. Stable samples were exposed to sonic waves for 15, 30, 45 and 60 min to inspect the thermal conductivity dependency on the sonication duration. Thermal conductivity improvement of EG was observed in all cases due to the presence of WO3 nanoparticles. Based on experiments, the best thermal conductivity enhancement has reached up to 32.38%. The rate of thermal conductivity enhancement was higher at low mass fractions. Temperature rising was found to amplify the positive nanoparticles efficacy. Eventually thermal conductivity improvements due to enlarged sonication time were reported up to 4%. (C) 2020 Elsevier B.V. All rights reserved.