Towards sustainable ships: Advancing energy efficiency of HVAC systems onboard through digital twin

Digital twin technology has proven effective for optimizing the energy performance of various ship systems, particularly in power and energy management. However, its application has not extended to HVAC systems. This study introduces a novel framework based on a dynamic simulation tool that accounts for the transient thermal conditions of the ship. It enables the assessment of thermal loads, energy needs, and HVAC system design, along with evaluating of the energy performance across different configurations. The tool can function as a digital twin onboard ship equipped with IoT sensors, providing real-time energy performance monitoring and optimization. Beyond offering swift energy, economic, and environmental analyses, it also allows for real-time adjustments to enhance energy efficiency. The framework integrates a 3D geometrical model of the ship into an energy performance dynamic simulation model. It incorporates actual operating conditions, including real ship load profiles, hourly weather parameters, and the ship's location and orientation. A proof-of-concept demonstration of this framework is provided for a medium-sized ship, with a detailed geometrical model that includes 1595 thermal zones and accommodates 1750 passengers and 880 crew members. The reference scenario explores a typical HVAC system, while five different interventions and six different combinations are explored. The results highlight potential fuel savings ranging from 0.17 % (−45.95 t/y) for setpoint temperature attenuation to 1.50 % (−0.411 kt/y) for the combination of setpoint temperature reconfiguration with variable external fresh air based on usage-based criteria.