Principle and Preliminary Calculation of Ocean Thermal Energy Conversion

Ocean Thermal Energy Conversion (OTEC) is the use of a high surface temperature of the water with the low temperature of the water at a certain depth thus creating a heat engine.The working fluid in such a cycle will need to have a low boiling point.Ammonia will be used as the working fluid in this cycle.The cycle will be a Rankine cycle similar to that of a steam power plant.There will be a pump, boiler (in this case the oceans surface water), turbine, and condenser (in this case the oceans water from 1000 meters deep).After numerical analysis of the system, it is found that the overall efficiency of this configuration is relatively low in comparison to the most widely used power generation technologies.In the first analysis, the Carnot Efficiency was found to be 8.03% while the Rankine cycle efficiency was 6.99%.In the second analysis of the system, there was a mass flow rate of 1000 kg/s.The working fluid and temperature difference were accounted for in the heat exchange of the warmer surface water to the cold water used in the condenser.In this analysis the Rankine cycle efficiency was found to be 3.97% and the Carnot efficiency in this example was 4.35%.In a real application the pump uses up most of the power generated due to having to pump water from 1000 meters deep.