SELECTION AND VALIDATION OF A MINIMUM-COST COLD WATER PIPE MATERIAL, CONFIGURATION, AND FABRICATION METHOD FOR OCEAN THERMAL ENERGY CONVERSION (OTEC) SYSTEMS

摘要

Ocean Thermal Energy Conversion (OTEC) can exploit natural temperature gradients in theoceans to generate secure baseload electricity free from global warming emissions, as well asfresh water. The #1 acknowledged challenge of constructing an OTEC plant is the Cold WaterPipe (CWP), which draws cold water from the ocean depths up to the surface, to serve as thecoolant for the OTEC Rankine cycle. For a commercial-scale plant, the CWP is not only 1000min length, but also is on the order of 10m in diameter.This paper describes work done recently developing the advanced fiber composite CWP forLockheed Martin's (LM) emerging OTEC line of business. The work started with deciding onthe minimum-cost CWP architecture, materials, and fabrication process, adopting an overallapproach of building an integral CWP down into the water directly from the floating OTECplatform. It then proceeded to a small-scale Proof-of-Principles validation of the innovativefabrication process. More recently, key elements of the process and apparatus have beensuccessfully validated at a 4m/13 ft. diameter scale suitable for a future OTEC Pilot Plant. Thevalidations have included assembly of sandwich core rings from hollow pre-pultruded “planks,”accurate machine-based dispensing of overlapping strips of thick fiberglass fabric to form thelengthwise-continuous face sheets, and stepwise resin infusion/cure of 4m diameter workpieces,successfully obtaining a non-discernable knitline between successive infusions.