The PV panel temperature increase causes the drop in output power and electrical efficiency . The power generation of PV module is highly influenced by the temperature and so cooling is required to increase the PV panel electrical efficiency. PV panel electrical efficiency can be increased by keeping the low operating temperature as low as possible, preferably at temperature of 250 C and irradiation 1000 w/m2 . The temperature regulation with efficient control methods of PV modules can increase its efficiency by a significant level. The PVT-PCM systems elevated about 28 to 42% more heat storage capacity than that of for a longer period and around 8 to 12 % escalation in output. The application of phase change materials (PCM) can be a better solution for this purpose, because phase change material (PCM) has large energy storage capacity and nearly constant charging / discharging temperature during phase change transitions .It can be used to regulate the PV cell temperature and store the thermal energy for solar heating systems photoelectric conversion efficiency of a PV system was improved by using different PCM. In this study we are trying to increase the efficiency by using different fin layout of the heat sink and comparing the experimental data for optimal fin design to effectively disperse heat through PCM material. The PVT panel surface back side was attached with the aluminum container with different (Geometric, Spherical & fins) configurations with PCM and with out PCM of single/different materials. Present study carried on aluminum H-30 box holding PCM material with fins and covering plate to which the photo voltaic cell attached then a different sensors to collect temperature data and irradiation levels at different regions. The design parameters was changed with fins and geometrical shape and found the derating factor. The derating factor was found with fins and with out pins along with PCM and with out PCM. Both experimental and theoretical values were compared ,the study revealed that the derating factor value was 13.2 without PCM the and 4.40 with PCM with out fins . The results revealed that relation between experimental measurement values and theoretical values . The study confirmed PCM with better fin design will increase the effective surface area can increase the cooling of PVT panel , results the escalation in electrical out put