Experimental studies on a closed cycle demonstration OTEC plant working on small temperature difference

Ocean thermal energy conversion (OTEC) technology utilizes the temperature difference between the warm surface water and deep coldwater of the ocean to operate a heat engine to generate electricity. An experimental study was carried out on a newly designed closed cycle demonstration OTEC plant with the help of temperature and pressure measurements before and after each component. An increase in the warm water temperature increases the heat transfer between the warm water and the working fluid, thus increasing the working fluid temperature, pressure, and enthalpy before the turbine. The performance is better at larger flowrates of the working fluid and the warm water. It is found that the thermal efficiency and the power output of the system both increase with increasing operating temperature difference (difference between warm and cold water inlet temperature). Increasing turbine inlet temperatures also increase the efficiency and the work done by the turbine. The efficiency and the power output increase with increasing ratio of warm water to coldwater flowrates. A maximum efficiency of about 1.5% was achieved in the system. The findings from this work can contribute to the development of OTEC technologies. (C) 2012 Elsevier Ltd. All rights reserved.