ENERGY ANALYSIS OF A CLOSED OCEAN THERMAL ENERGY CONVERSION CYCLE IN SOUTHERN CASPIAN SEA

Wave energy, tidal energy and thermal energy are the three main categories of the ocean energy. The stored thermal energy in the ocean acts as a heat source and can be used to run a thermodynamic cycle. The paper presented here investigates the potential temperature gradient in southern Caspian Sea during summertime in Iran. The variation of extracted net power, heat rejection rate and efficiency of an ocean thermal energy conversion power plant are analyzed with different possible turbine inlet temperature. The analysis is performed by two popular Rankine cycle working fluids (ammonia and R-134a) for a 15MW OTEC power plant where the turbine inlet temperature varies between 17℃ and 23℃. The results showed that for the same power generation at turbine, R-134a requires more working fluid mass flow rate but the rejected heat at condenser is essentially remains constant. It is also concluded that increasing inlet temperature for 6℃ will cause the efficiency to change by factor of 2.