Integrating cooling systems with photovoltaic (PV) modules represents a very important aspect of keeping modules within acceptable operating temperatures. The objective of this study is to analyse the performance of each series-connected PV cell in photovoltaic thermal (PVT) modules. The importance of this analysis is due to the consideration of the variable operating temperature values of the PV cells, resulting in a different performance of each PV cell. The PVT modules are cooled with water serving as both a heat sink and a solar heat collector. This enhances the electrical efficiency value of the PVT modules by preventing them from elevated temperature values, while the recovered thermal energy can be utilised to increase the overall PV effectiveness. The new consideration in this study over the existing ones is the temperature distribution of each PV cell is applied for the calculation of the current voltage characteristics of the PV modules, which makes the analysis more accurate. The variance in the temperature values is a result of the temperature gradient of the fluid flowing through the pipes where the heat exchange differs in the flow direction. The potential of this study becomes more important for countries of high ambient temperatures and high solar intensity.