Abstract
Ocean Thermal Energy Conversion (OTEC) has been attracting attention for its stability and potential for integration with deep seawater utilization. For a Floating OTEC plant, developing an ultra-large-diameter Cold Water Pipe (CWP) has long been a major challenge. This preliminary study explores the economics, structural performance, and design feasibility of a concept of a multiple CWP system for floating OTEC. As a case study, a baseline design comprising a ship-shaped platform, a spread mooring system, and a GFRP CWP is considered. The economics of multiple CWPs are evaluated by varying the diameter, flow velocity, and number of pipes while maintaining a constant flow rate. The results revealed that, for each pipe configuration, there exists an optimal combination of diameter and flow velocity, and that the economic impact associated with adopting multiple CWPs is negligible when optimal designs are considered. Furthermore, the dynamic characteristics of the coupled platform–mooring–CWP system under extreme environmental conditions are investigated using the optimal design candidates. Time-domain simulations confirm that the concept using multiple CWPs is technically feasible for floating OTEC applications.