Energy and Exergy Analysis of the Ocean Thermal Energy Conversion Combined Cycle Power Plant with a Two-stage Turbine and Using Thermal Power Plant Condenser Output Warm Water

The increasing in energy demand by the limitation of fossil-fuel resources and the environmental pollution caused by fossil fuels has attracted much attention to renewable energy sources. In the ocean thermal energy conversion system , the temperature difference between the warm water of the sea surface and its deep cold water is used to generate electric power. Due to low temperature difference between hot and cold sources, thermal efficiency of these systems is lower compared to fossil-fuel power plants. In the present study, as a proposed cycle to increase the production capacity and thermal efficiency of the cycle, the warm water output from the thermal power plant condenser was used instead of surface water, and the two-stage turbine and reheating between the two stages were used. The energy and exergy analysis of proposed cycle was done. The results showed that average of electricity produced in cycle per month increases 27.52 MW and energy and exergy efficiencies were 3.34% and 17.2%, respectively. In the following, proposed cycle was run using warm water output from Neka combined cycle power plant condenser. The results showed that by using the outlet water from the condenser of combined cycle power plant the average net electrical power was produced by 17.72 MW per month. Also, an average of 18829 tons per day of fresh water was produced, and the thermal efficiency of the combined cycle improved by 1.87%.