The practical use of Ocean Thermal Energy Conversion (OTEC) is refocused because it is possible to supply stable electric power and a variety of integrated applications. This paper investigates on the thermal performance of Double Stage-Rankine cycle that has independent equipment respectively in two Rankine cycles. Turbine power and thermal efficiency of Double Stage-Rankine cycle is found to be larger than these of Single-Rankine cycle. Moreover, the maximum output power of Double Stage-Rankine cycle is found to be larger than both these of Single-Rankine cycle and Kalina cycle.
In the new century, global warming and energy problem is becoming more critical. The practical use of Ocean Thermal Energy Conversion (OTEC) is refocused because it is possible to supply stable electric power and a variety of hybrid uses, such as the seawater desalination, house cooling and aquaculture, etc. The OTEC power plant is the system for generating electric power using temperature difference between warm surface seawater and cold deep seawater. Ocean thermal energy has a huge energy; however, energy density and temperature difference are small. OTEC system is smaller than that in the conventional thermal or nuclear power systems, and subsequently. The system cycle thermal efficiency is theoretically small. Therefore it is necessary to enhance the thermal efficiency of the OTEC system in order to use a practical plant. This paper investigates on the thermal performance of Double Stage-Rankine cycle that has independent equipment respectively in two Rankine cycles. The Double Stage- Rankine cycle was compared with the conventional Rankine cycle and Kalian cycle and has shown better performance in terms of maximum output power. The advantage of using two independent cycles is that it decreases irreversible losses in heat transfer equipment.
