Ocean thermal energy conversion (OTEC) uses the natural thermal gradient in the sea. It\nhas been investigated to make it competitive with conventional power plants, as it has huge\npotential and can produce energy steadily throughout the year. This has been done mostly by\nfocusing on improving cycle performances or central elements of OTEC, such as heat exchangers. It\nis difficult to choose a suitable heat exchanger for OTEC with the separate evaluations of the heat\ntransfer coefficient and pressure drop that are usually found in the literature. Accordingly, this\npaper presents a method to evaluate heat exchangers for OTEC. On the basis of finite-time\nthermodynamics, the maximum net power output for different heat exchangers using both heat\ntransfer performance and pressure drop was assessed and compared. This method was successfully\napplied to three heat exchangers. The most suitable heat exchanger was found to lead to a maximum\nnet power output 158% higher than the output of the least suitable heat exchanger. For a difference\nof 3.7% in the net power output, a difference of 22% in the Reynolds numbers was found. Therefore,\nthose numbers also play a significant role in the choice of heat exchangers as they affect the pumping\npower required for seawater flowing. A sensitivity analysis showed that seawater temperature does\nnot affect the choice of heat exchangers, even though the net power output was found to decrease\nby up to 10% with every temperature difference drop of 1 DegreeC.
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