Design, fabrication, and performance test of R32-OTEC pilot plant

Abstract

In this paper, we present the results of the design, fabrication, installation, and operation of a 20-kW OTEC (ocean thermal energy conversion) pilot plant. The results can be used as basic data for the design of commercial plants with capacities in excess of 40 MW. To perform an experiment on the 20 kW OTEC, a closed OTEC cycle was designed and fabricated at the Ocean Water Plant Research Center. The cycle utilizes surface ocean water as its heat source and deep ocean water as its heat sink. R32 (Difluoromethane, CH2F2) was used as the working fluid, and the temperature of the heat source and heat sink were 26°C and 5°C, respectively. A semi-welded-type heat exchanger was used as the evaporator and condenser, and the OTEC cycle was designed for a gross power of 20 kW. The advantages of the semi-welded-type heat exchanger include easy maintenance of the gasket-type heat exchanger and the rare leakage of the welded-type heat exchanger. The plate arrangement of the semi-welded-type heat exchanger comprised one welded channel for the working fluid and another gaskettype channel. The gross power of the turbine was determined to be 20.49 kW. The evaporating capacity was calculated as 1,020 kW, and the cycle efficiency was determined to be about 2.00%. Copyright ？ 2014 by ASME.