HELM is a tool for the performances comparison of innovative energy systems on board ships, both for concentrated and distributed generation applications. The tool database has been developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines, micro gas turbines), fuels (hydrogen, natural gas, diesel) and related storage technologies. Many of these data have been collected also thanks to the laboratory experience of the authors’ research group on different innovative energy systems.
From the database, a wide range of maps has been created, correlating costs, volumes, weights and emissions with the installed power and the operational hours required, given by the user as input. The tool highlights the best solution according to the different relevance chosen by the user for each key parameter (i.e. costs, volumes, emissions). It is worth noting that the methodology has a general value, as the tool can be applied to both the design of new ships, and to the retrofit of already existing ships in order to respect new requirements (e.g. more and more stringent normative in terms of pollutant emissions in ports and restricted areas). Furthermore, the database can be easily extended to other generation and storage technologies.
Concept and approach
Many parameters can affect the choice of the best technology in terms of economic and technical aspects but also comfort and expected navigation areas are relevant. In order to take into proper account these many parameters, the Thermochemical Power Group (TPG) at University of Genoa has developed a tool that calculates all the main properties for each technology suggesting the most suitable for the desired application: HELM (Helper for Energy Layouts in Maritime applications).
The core of the tool resides in a strong database, developed through a deep and detailed market investigation and private communication by different companies, considering both storage systems and power units. From this database, specific maps have been created correlating the main parameters (such as weights, volumes and costs) with the size required by the system.
The main inputs are the power required by the ship and the operational hours without docking. In this phase, the power required has to be intended as the maximum power necessary for a proper operation of the boat. This is a conservative choice since in the real operation, the maximum power will not be required continuously, but there will be operational time-dependent profiles where the maximum value is the maximum power considered in this phase. Multiplying these values, the energy required by the ship is obtained. Dividing this energy by the system efficiency, the amount of fuel needed is calculated and then used as input in the dedicated storage map reporting its parameters (weight, volume, cost). For what concerns the power unit, the size is given by the power required, therefore this value can be directly inserted in the dedicated power unit map to obtain the power unit parameters. Furthermore, the emissions are evaluated using maps for each configuration where the input is the amount of fuel consumed depending both on fuel and power unit.
HELM gives an evaluation of the most suitable technology for the scenario considered; this evaluation is represented by the score of each technology: the best application obtains the highest total score. The total score for each solution is the sum of single scores obtained for the four evaluation categories: volume, weight, cost and emissions. For each category, the score goes from a minimum of 1 up to a maximum of 10.
Since each application has specific requirements (i.e. a ship mainly used for navigation in ECAs will consider emissions as the most relevant parameter), the resulting score is affected by the relevance parameters initially set, depending on the application considered. The score for each technology is multiplied by the corresponding relevance (i.e. if weight relevance is 3, the maximum score for the weight category is 30 points). Once the calculation is completed, the tool also provides automatic limitations concerning the ship size initially selected (small, medium, large depending on the application). Hence, taking into account the ship’s dimensions, the tool highlights the parameters that are not feasible for the chosen application.
Fields of application
HELM can be used in a preliminary design phase. Both in case of new applications or renovation of existing ships. Every boat is strictly characterized by the scenario of application. Therefore it is necessary to choose accurately the relevance parameters in order to properly analyze the scenario. All the varieties of ships can be studied with this tool, from small to large size. Therefore yachts, ferries and cruises of different size can be analyzed. Furthermore it is possible to analyze and simulate the cases where only energy for services (such as hotel services) or the overall power, propulsion included, are taken into account.
Publications
Clean energy production by PEM Fuel Cells on tourist ships: A time-dependent analysis
M. Rivarolo, D. Rattazzi, T. Lamberti, L. Magistri
International Journal of Hydrogen Energy, Volume 45, Issue 47, 25 September 2020, Pages 25747-25757
A design tool for the performances comparison of innovative energy systems for naval applications
D. Rattazzi, M. Rivarolo, T. Lamberti, L. Magistri
E3S Web Conf. Volume 113, 2019 SUPEHR19 SUstainable PolyEnergy generation and HaRvesting Volume 1