WHR systems based on sCO2 gas turbines for marine applications: The effect of route environmental conditions on performance

• A sCO 2 gas turbine WHR system depends on environmental conditions in marine uses. • At the same location, WHR efficiency is 47 % lower in summer than in winter. • At the same location, a seasonal 11 % reduction in IES energy efficiency is observed. • The WHR power reaches up to 9 MW, with an increasing close to 30 %. • WHR significantly reduces CH 4 consumption and CO 2 emissions. Waste Heat Recovery is one of the viable solutions to enhance the global efficiency of propulsion and energy systems in marine applications, thus mitigating and reducing the greenhouse gas emission from shipping. In this context, WHR systems based on supercritical CO 2 Brayon Cycle are considered an emerging and interesting technology. The aim of this study is to investigate the off-design behaviour of an integrated energy system based on a commercial gas turbine (LM2500+) and a bottoming partially preheated and recuperated sCO 2 gas turbine, considering the variations in environmental conditions, that a vessel may encounter along commercial routes. In particular, an energy, environmental and exergetic numerical analysis has been carried out considering two different routes connecting Europe (the departure port is Naples in Southern Italy) to Kuala Lumpur (Malaysia), passing or not through the Suez Canal. The same routes have been considered in two different seasons (March 2024 and August/September 2024), to underline the effect of air and seawater temperatures on the overall performance of the integrated system. The steady-state thermodynamic analysis has been carried out using the commercial software Thermoflex. The results of the analysis highlighted that the overall efficiency of the system can vary up to 11 % in the same location, in different seasons and can reach a value closed to 49 %, dropping to 42 % in the worst-case scenario. At the same time, the efficiency of WHR can change up to 40–47 % in the same location under different environmental conditions considered.