Research on Heat Transfer Performance of Cold-Water Pipe in Ocean Thermal Energy Conversion System

Ocean Thermal Energy Conversion (OTEC) is characterized by its abundant reserves and pollution-free nature, enabling stable power generation around the clock. Since the power output of an OTEC system is significantly influenced by the energy available from cold and warm seawater, the accurate evaluation of the outlet temperature of the cold-water pipe (CWP) is crucial. To analyze the heat transfer performance of the CWP, this paper investigates the temperature field of the OTEC CWP and employs numerical simulation methods to conduct finite element analysis of the temperature field under different discharge conditions. The results indicate that during the pumping of deep-sea cold water through the CWP, heat is absorbed from the warmer upper seawater layers. When the pumping discharge rate is higher, the shorter fluid residence time due to higher flow velocity results in a lower outlet temperature. Compared to steel CWPs, high-density polyethylene (HDPE) is more suitable for OTEC systems due to its lower thermal conductivity and density.