해양 온도차 발전 시스템에 관한 여러 가지 연구

초록

For the past few years, the concern for clean energy has been increased greatly and hence in this paper, Ocean Thermal Energy Conversion(OTEC) power plants are studied as a viable option for the supply of clean energy. Thermodynamic performance of three closed cycles of a plain Rankine cycle, regenerative Rankine cycle, and Kalina cycle is evaluated under the same condition and various working fluids are considered as well. The evaporator and condenser are modeled by a UA and LMTD method wjile the turbine and pump are modeled bu considering isentropic efficiencies. As for the working fluids, R22, R134a, R32, propylene, ammonia are used for the Rankine and regenerative Rankine cycles while R32/R134a and ammonia/water mixtures are used for the Kalina cycle. Calculated results show that newly developed fluids such non-ozone depleting refrigerants as R134a and R32 perform as well as R22 and ammonia. The regenerative Rankine cycle showed a 1.5 to 2% increase in energy efficiency as compared to the Rankine cycle while the Kalina cycle employing ammonia/water mixture showed 2-3% increase in energy efficiency. Even though the increase in energy efficiency by adding some more components to the system does not seem to be much, that will help in the long run for the adoption of OTEC technology. Also, by changing the heat exchanger option, Kalina cycle can be made to be more energy efficient.