발전 및 해수담수화를 위한 태양열 해양온도차 시스템 성능평가

Abstract

Ocean thermal energy conversion(OTEC) is a electric power generation method that utilizes temperature difference between the warm surface seawater and cold deep seawater of ocean. As potential sources of clean-energy supply, OTEC power plants' viability has been investigated. However, The OTEC system has problems of low efficiency and high investment cost because the temperature difference between the surface and the deep sea is small, long pipe line and pumping cost for using cold deep water. Therefore, in this present study, the OTEC system combines with solar system. It evaluated the thermodynamic performance of solar-OTEC convergence system for the simultaneous production with electric power and desalinated water. The performance analysis of solar-OTEC convergence system was carried out as the fluid temperature, saturated temperature difference and pressure of flash evaporator under equivalent conditions. The results showed that the performance of solar-open OTEC system is the highest at the flash evaporator pressure of 10 kPa. At this time, the system efficiency, electric power and desalination production enhancement ratios were approximately 3.9, 13.9, 5.1 times higher than that of the base open OTEC system, respectively. The results showed that maximum system efficiency, electric power and fresh water output of solar-open OTEC system show at 40, 10, 2.5 kPa of the flash evaporator pressure, respectively. And the irrespective enhancement ratios were approximately 15.3, 5.3, 8.6 times higher than that of the base open OTEC system. Also, performance of solar-OTEC system is the highest in the flash evaporator pressure of 10 kPa. Also, the performance of solar-hybrid OTEC system is the highest at the inflow fluid temperature of evaporator of 80℃. The system efficiency, electric power and desalination production enhancement ratios were approximately 3.4, 3.5, 14.4 times higher than that of the base hybrid OTEC system.