Technical and economic analysis of organic rankine cycle system using low-temperature source to generate electricity in ship

Increasing requirements on the economic efficiency and environmental compliance of sea transportation are drawing a larger attention on emission, energy efficiency and fuel consumption of seagoing ships. Waste Heat Recovery (WHR) is one of the solutions to meet these requirements. WHR systems utilizing high temperature sources such as exhaust gas boilers are state of the art and installation in cooling water system is not yet utilized for WHR. One opportunity is the installation of an Organic Rankine Cycle (ORC) system to recover the low-temperature waste heat emitted by the ship machinery plant. The authors have analysed the technical and economic feasibility of an ORC installation in the jacket cooling water system of a 7900 kW main engine on a container ship. The system uses R-134a as refrigerant and consists of four main components. Fuel saving potentials and necessary investment costs have been contrasted in order to determine the return on investment. Objective was to quantify the amount of electrical power which can be generated at typical loads of the main engine. The results show that the ORC system would provide an average electrical power of 57,69 kW in the load range 77,5–100% of the main engine. The investment costs would return over a period of 10 years.