The usage of natural convection has many applications for cooling and controlling the temperature of electronic components. Therefore, in the present simulation, the average Nusselt number and maximum temperature of surface's electronic components are studied by adding nano-emulsion phase change material (NPCM) with water as the base fluid. Because, the previous studies show that adding NPCM to a base fluid can increase the specific heat capacity of a mixture in order to change the phase in the solid–liquid transition. The used NPCM consists of n-eicosane as a core and sodium lauryl sulphate as a shell. The geometry includes a square enclosure with the top wall as a cold wall and the bottom wall as a hot electronic component with constant heat flux. In the current study, the effects of Rayleigh numbers ((Formula presented.)), cold wall temperature ((Formula presented.)), and volume fraction of NPCM ((Formula presented.)) are investigated to understand the behaviors of NPCM on heat transfer parameters. The observations show that the average Nusselt number is directly related to Rayleigh number and thickness of the phase change zone. Moreover, the optimal value of volume fraction is 0.012 that increases average Nusselt number 7.3% and 5.4% for low and high Rayleigh numbers, respectively.