A novel dynamic simulation approach for the waste heat energy recovery of modern cruise ships sailing in the Northern sea

In the last years, the International Maritime Organization has been imposing severe and restrictive regulations on pollutant emissions to reduce the environmental impact of modern ships. Thus, the sustainable design of modern cruise ships is crucial to comply with these regulations. In this paper, a novel approach for assessing the potentiality of energy-saving technologies and strategies for ship applications is presented. This approach is based on dynamic simulation, and it is implemented in a suitable tool assembled in TRNSYS environment. Here, the ship-envelope as well as the related ship energy plant systems are modelled and simulated. Also, to consider different ship routes and relative dynamic boundary conditions variations during the cruise, a suitable tool capable of producing customized weather data is developed. To show the effectiveness of the proposed approach, a novel case study is presented. It refers to a modern cruise ship fuelled by liquified natural gas cruising in Norwegian fjords sea. Here, the waste heat of exhaust gases and engine jacket water of LNG engines are exploited to supply different thermally activated devices. Specifically, heat exchangers are adopted for supplying hot water to air-handler units; multi-stage flash distillation systems are adopted for freshwater production whereas steam turbine system, organic Rankine cycle device and molten carbon fuel cells are utilized for electricity production. Suitable control and decision strategies for optimizing the waste heat recovery are implemented. Eight different system layouts are analysed and promising results in terms of primary energy savings (18.1%), avoided pollutants emission (24.4 ktCO2/y, 40.0 tNOx, 90.0 tSOx, 84.0 tPM2.5) and simple payback (0.68 y) are achieved.