The energy imbalance always exists after the Industrial Revolution. Recently, the researchers try to solve this issue for saving the energy not because of awareness of the importance of limitation of energy source but because of economic and environmental benefits. Thus, the waste heat from industries and power plants would be a good energy source for resolving the mismatched energy between supply and demand depending on time bands and residential/industrial locations. One of easy and efficient methods to solve the issue is to use of storing thermal energy. The water heat storage tank with thermal stratification in the form of sensible heat is a very simple and efficient way. In the concept of abovementioned energy storing method, the achievement of rapid and stable thermal stratification has great advantage for energy storage and distribution. This study numerically investigates the nozzle number effect of water inlet/outlet with three-dimensional models using the computational fluid dynamics software. This study shows the temperature distributions inside the water tank and evaluates the degree of stratification on each case. As the number of nozzle increases, the thermal stratification encourages. Moreover, it was found that the speed of thermal equilibrium on horizontal region near water injector affects a high degree of thermal stratification on vertical region.