Thermoeconomic analysis of a new waste heat recovery system for large marine diesel engine and comparison with two other configurations

Abstract

ABSTRACT The utilization of waste energy sources and their treatment are very important in marine science due to their numerous benefits such as energy saving and feasible fuel conservation. Hence, this paper proposes three different configurations of waste heat recovery systems for the successful recovery of waste heat sources in diesel engines to obtain the highest level of power generation from the ship engines. The results of this study indicate that the new organic Rankine cycle system with the utilization of jacket cooling water presents better thermodynamic efficiencies and lower unit power cost in comparison with two other systems. Among the evaluated refrigerants, the R600 shows better thermoeconomic characteristics among other refrigerants. Several analyses show that the utilization of water jacket cooling beside the exhaust gases of the engine resulted in the fuel conservation of 209486 gallons per year of operation, which is about 23.3% higher than the base system without jacket cooling exchanger. Furthermore, it is observed that increasing the engine loading improves the net power output and also the payback period of the systems. This method might provide researchers with information to assess the benefit and the cost of each configuration modification and determine the direction of further improvement.