Heat exchangers are a widely used as a device for meeting the heat transfer requirement in industrial applications. Many types of innovative heat exchanger designs have been implemented with the aim of increasing heat transfer. Numerous experimental and numerical studies are available in the literature on obtaining heat transfer and temperature distribution these systems. In the present study, an analytical model was developed to solve the nonlinear differential energy equation in order to estimate the temperature distribution in the parallel and counter flow double pipe heat exchanger. These analytical solutions have occurred of Bessel functions. A numerical study was carried out to determine the validity of the analytical results. Moreover, the analytical and the numerical results were compared with each other. Water is used as a fluid and the analyses were carried out for laminar and steady-state flow conditions at a certain Reynolds number (Re=1500). The findings showed that the analytical results for temperature distribution in the radial
direction are in good agreement with the numerical results for all the flow conditions. However, the analytical model for the temperature distribution in the axial direction yielded more accurate results in the parallel flow conditions.