This study uses computational fluid dynamics software to model heat transfer in a water pipe as the fluid reaches supercritical conditions. The model considers both conductive heat transfer through the pipe walls and convective heat transfer from the fluid flow. Validation is performed against existing literature on supercritical water heat transfer in pipes. The results show that downward flow has the best heat transfer, while upward flow performance deteriorates and recovers over the length of the pipe due to buoyancy effects. Both improvement and deterioration of heat transfer are observed under different conditions.