Design Optimization of Surface Seawater Intake Piping for Hybrid Ocean Thermal Energy Conversion Pilot Plant

ABSTRACT Hybrid Ocean Thermal Energy Conversion (H‐OTEC) systems are characterized by the adoption of both open‐loop and closed‐loop Rankine cycles. In the closed‐loop configuration, a working fluid such as ammonia is evaporated in a heat exchanger, utilizing the heat from water vapor generated in a vacuum chamber by warm surface seawater introduction. The vapor is then expanded through a turbogenerator to produce electricity before being condensed in a cold‐water heat exchanger using cold water. In Malaysia, significant advancements are being made in the technology for seawater suction systems, particularly for applications in fish breeding, farming, desalination plants, and power generation. The operation of an H‐OTEC Experimental system at UPM I‐AQUAS, Port Dickson, Malaysia depends on surface seawater for turbine operation, necessitating the installation of a piping system spanning 336 m from the H‐OTEC facility to the suction location. Challenges associated with seawater intake systems include pump cavitation due to high suction head, pipe contamination by organisms such as barnacles and algae, pump placement, strainer size, and pipe diameter intake. The primary objective of this study is to provide valuable insights, conduct field testing, and gather necessary data for the development of the first‐of‐its‐kind surface seawater piping system for H‐OTEC in the Asian region. This objective was accomplished through the installation of a centrifugal pump unit with a flow rate of 40 m 3 /h (600 L/min), the laying of 106 mm inner diameter parallel pipes, installation of strainers, and a booster pump connected to a 125 A HDPE pipe. The collected data provides the necessary input in establishing the layout design and location selection of the seawater intake pipe, introduce a novel helical crossflow self‐cleaning suction screen water intake system, facilitate weight structure design, and enable pump sizing and suction pump analysis.