In this work, the assessment of power harvesting in electronic modules during its operation is experimentally investigated. The phase change material (PCM) based natural cooling is analyzed with a developed model using different circulating fluids such as DI water, ethanol, and methyl acetate respectively. The experiments are conducted to evaluate the power harvesting by PCM for circulating fluids at the different heat input between 60 and 110 W. The highest percentage of waste heat extraction obtains for methyl acetate of about 98.7% whereas 96.5% and 97.7% for DI water and ethanol respectively. It is because of the low boiling point and heat of evaporation at high heat input. The thermal resistance of methyl acetate is less of about 0.237 K/W while 0.655 and 0.398 K/W for DI water and ethanol respectively owing to high vapor flow rate and less subcooling effect. The maximum power harvested by PCM with the effect of vapourized methyl acetate is found as 9.41 W owing to less time to reach the steady-state temperature (SST) of PCM at 110 W. © 2020, INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH. All rights reserved