Use of a commercial dynamic process simulator to enhance energy efficient ship design

Global maritime industry is heading challenges due to constantly increasing bunker oil prices and tightening environmental regulations. Energy efficiency has become increasingly important to ship owners and builders. A modern ship includes complex power plant with mechanical, electrical and thermal systems. Practically all energy used onboard originates from fuel; only 40-60 % of this energy is fully utilized. Significant savings are achievable by improving waste heat utilization. Complex and interconnected systems challenge this kind of improvement work; this is where simulation on ship systems stands out. Simulation technology has been used for energy systems analysis already for decades in onshore energy industry; now it is more and more also applied in marine engineering. In this study a commercial dynamic process simulator Apros was used to model and simulate energy systems of a cruise ferry Viking Grace, which was delivered to Viking Line in January 2013 by Meyer Turku shipyard (at that time STX Finland). The ferry features novel energy saving solutions, such as a waste heat accumulator system and cooling options by liquefied natural gas (LNG) vaporizing, and by sea water. These systems were modelled and validated against measurements from the actual system. The paper discusses the use of dynamic simulator within the ship energy efficiency context, and illustrates the modelling conducted and the main results obtained. The study indicated potential for substantial benefits in introducing an overall ship systems simulation in the ship design process. The validation proved the reliability of the used dynamic simulation tool. The study showed that a proper simulation model can give valuable insights into the design of energy efficient ship including operability aspects. Especially, simulation provides a tool to evaluate new design concepts in new buildings, and help to find possible ways to improve the energy efficiency in existing ships. Recently Viking Line has started another energy efficiency improvement project together with Meyer Turku shipyard and a Swedish company Climeon to convert excess heat into electricity. First simulation results of this new Climeon's product called "Ocean 100" are briefly presented in the results section.