Thermodynamic analysis of a dual loop cycle coupled with a marine gas turbine for waste heat recovery system using low global warming potential working fluids

The combined use of generation and propulsion gas turbines and steam turbines is efficient and can meet the environmental regulations. In this study, the thermodynamic performance of waste heat recovery systems of a marine gas turbine was analyzed. These systems combine the steam Rankine cycle and the organic Rankine cycle to form a dual-loop cycle. Working fluids R32, R134a, R152a and R1234yf, that are low-global warming potential, were selected for the organic Rankine cycle. All of the working fluids exhibited better performance than for the single-loop cycle, and R134a exhibited the greatest efficiency with energy and exergy efficiencies of 29.50 % and 45.58 %, respectively. The most important components contributing to the exergy destruction of the cycle were the heat exchangers. Therefore, it is essential to select the optimum heat exchanger as well as the working fluid in the waste heat recovery system for marine gas turbines.