Optimering av OTEC-system

Sammanfattning: Ocean Thermal Energy Conversion, OTEC, is a sustainable energy conversion technology that is not yet commercialized. OTEC is a technology that utilizes the temperature difference in oceans between the warm surface water and the cold water at 1 000 m depth to run a Rankine Cycle.   This technology can produce electricity and provide synergies like fresh water, air conditioning and aquaculture. A simulation program for three alternative OTEC systems has been created in order to decide which OTEC system is most profitable; closed, open or hybrid system. In this simulation a production cost analysis is performed in order to investigate and decide which one of the three systems that has the lowest production cost.   The production cost analysis also analyzes if the profitability is affected by the size of the facility. After these analyzes, the most profitable of the three different OTEC-systems is expanded by an installation of solar collectors in order to see if the thermal efficiency is improved.   The result shows that the most profitable system varies with the size of the facility. For smaller OTEC-plants the closed system is more profitable and when the size of the facility increases, hybrid systems proceed to give more profit. The simulation also shows that the production cost reduces with the size, which means the production cost gets lower for larger facilities. Therefore the most optimal concept is a large facility based on a hybrid system. Installation of the solar collectors indicates that the thermal efficiency improves significantly.