A novel method for optimal performance of ships by simultaneous optimisation of hull-propulsion-BIPV systems

Abstract

Shipping has been facing significant challenges due to strict limits imposed by the International Maritime Organization (IMO) to become more environmentally sustainable. In this regard, the use of solar energy, as a viable way to deal with the pollutant emissions caused by ships, has been attracted considerable attention. However, considerable investment costs, high area demands, and low performances of ships equipped with the photovoltaic systems have until recently been some of the significant challenges in the use of solar energy in the shipping industry. This paper proposes a novel method for the optimal performance of ships through the simultaneous optimisation of the hull-propulsion-building integrated photovoltaic (BIPV) system. Using the proposed method, the interaction effects among the ship hull, the BIPV system, and the propulsion system, as well as the impact of the wind and ship speeds on the BIPV system efficiency are considered. Ship operational conditions, including the sunshine duration, the clearness index, the ambient temperature, the latitude of the region, the view factor of the sky to ground, the wind and ship speeds, and the ship lifetime hour are also examined. Moreover, a probabilistic speed profile is employed to avoid a suboptimal design at a single ship speed. The performance of the suggested method is evaluated by designing a planing ship equipped with a waterjet propulsion system that operates in the Karun river, Iran. The non-dominated sorting genetic algorithm (NSGA-II) is used to solve the multi-objective optimisation problem of a planing hull-waterjet-BIPV system. Eight cases are compared to demonstrate the effectiveness and the promise of the proposed approach in different ship design problems with different displacements and BIPV area-to-deck area ratios. The results show the high performance of the adopted approach in cutting operating costs and greenhouse gas (GHG) emissions. Based on the results, the investment costs due to the BIPV system have been recouped within a year in different studied cases and scenarios. It is also found out that the interaction effects among the ship hull, the BIPV system, and the propulsion system are important to ensure the optimal performance of a ship.