In this study simple shell and tube heat exchanger was use to validate the experimental results with CFD results. Experimental validation proves that CFD is effective tool for thermal performance investigation. After experimental validation, main research work was focused on effect of latent heat storage on thermal performance improvement of simple shell and tube heat exchanger using PCM materials in it. CFD based investigation is done for charging (melting) and discharging (solidification) in shell and tube heat exchanger. Main conclusion of present work was to show the effect of various thermal parameters performance for shell and tube heat exchanger having charging and discharging conditions. Regression equation is generated for phase change materials (Natural wax of various types) for charging and discharging condition. Finally both regression equation is optimized using MOGA tool in MATLAB software. Thermal contours are also developed for more detailed study on all designs of shell and tube heat exchanger with PCM. CFD simulation was carried out on ANSYS FLUENT software.