H Enshaei

Sizing and modeling of a standalone hybrid renewable energy system

This paper presents optimal sizing, modeling and performance analysis of a standalone PV/Wind/Battery Hybrid Energy System (PWB-HES) for an off-grid residential application in Ansons Bay, Tasmania, Australia. The aim of the study is to find the optimal size of the photovoltaic (PV) panel, wind generation system (WGS) and battery storage (BS) that can satisfy the varying load demand throughout the year. In the proposed PWB-HES sources and the battery are connected to a common DC bus. A voltage source inverter is used to connect the dc bus to the ac side. The optimal combination of sources and energy storage was obtained based on solar irradiance, wind speed and typical residential demand of the selected site. The optimal sizing algorithm was implemented using the HOMER software. The optimal system is then modeled and simulated with SIMULINK software in order to examine the complementary characteristics of the solar and the wind power system to satisfy the load demand. Simulation results showed that the PWB-HES with optimal size obtained through HOMER is able to meet the load demand amidst the changes in solar irradiance and wind speed.

Development of a methodology for estimation of ballast water operation in UK ports

To avoid or mitigate risks associated with introduction of non-indigenous species, it is necessary to monitor and understand the quantity and origin of foreign and domestic ballast water discharged into territorial waters. It is not yet compulsory to report a ships ballast water operations in any ports within the UK. 38 ports have been contacted and their shipping operations from 2003 to 2008have been collected. Despite the diverse nature and format of the data, it has been possible to develop a correlation between the amount of cargo and ballast water operations for every port and hence estimate the potential amount of ballast water discharged. The proposed methodology has been used to estimate the total amount of ballast water discharged in UK waters and at individual ports. Based on this estimation, 20 UK ports with the highest amount of imported ballast water from foreign origins have been identified.

Liquefied Natural Gas as a Marine Fuel in Australia: Developing a Conceptual Framework for Strategic Decision-Making

When it comes to shipping large volumes of cargo over long distances, commercial shipping is the most efficient and cleanest mode of transport in terms of emissions. However, the inherently low-grade, high sulphur content fuel oils used in shipping are responsible for the emission of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOX), sulphur dioxide (SO2), volatile organic compounds (VOCs), black carbon (BC) and/or particulate organic matter (PM). According to recent studies, maritime industry accounts for approximately 2.2 percent and 2.1 percent of global CO2 and greenhouse gas (GHG) emissions respectively. Although a minor fraction of total global CO2 emissions, international shipping was responsible for 938 tonnes of CO2 emissions in 2012, and that figure is expected to increase by as much as 250 percent in 2050.

Fatigue condition under the engine room environment and improving work accuracy

Familiarization of the work could reduce the difficulty of a given task, and workers can perform the work quicker. However, familiarization of the work in a long term may cause the work to be boring as it generally reduces the stress. As a result, the worker might develop an unsafe behavior through reduction of alertness. Instead of repeatedly performing the tedious work, as a common method for maintaining the accuracy at work, there can be an alternative method by inserting a break into the working schedule. The types of work in the engine room are quite diverse since there are different types of engines and machineries operating together or independently. Nevertheless, the break taken by each engineer working in engine room might be different according to operating situation. This study uses an experimental case to investigate the fatigue and its relationship to work accuracy. This experiment utilizes an equipment consist of short pipes and flange connections used in engine room. A student carries out tightening experiments to keep the flanges in place by bolts and nuts. The biological reactions were measured in an activity by heartbeat sensor and electroencephalogram head-set. The tightened bolts were made loose by torque wrench, while torque was measured simultaneously. The relations between the biological reactions and the working accuracy are investigated according to elapsed time and presented in this paper. It was concluded that working environment in the ship engine room could be improved using the optimum rest time concept, discussed for the working accuracy and safety level.

Floating power platforms for mobile cold-ironing

The colloquial term ‘cold-ironing’ refers to the shore power connection when a ship is at berth. Even though, cold-ironing is not new to the shipping industry only recently it received more attention, mainly due to strict emission regulations. When a ship receives shore power, its emissions can be eliminated and thus cold-ironing is becoming a popular service sought by ships that berth at emission controlled ports. Generally, the shore power connection is available only at berth and thus emissions from the ships that are anchored in and around the port is still a significant issue. This paper proposes a floating power platform for ‘Mobile Cold-ironing’ of anchored ships. In the proposed system, a fuel cell — battery hybrid system is used as the source. Efficacy of the proposed system in supplying dynamic loads is verified with simulation results.

Effect of load changes on hybrid electric ship power systems

Load transients are often the cause of power failures leading to blackouts or malfunction of sensitive equipment on-board electric ships. Having number of operating modes, hybrid electric ships face the same issue at a higher probability. This paper focuses on assessing the effects of load changes on hybrid electric ship power systems at different operating modes. Hybrid electric propulsion and the different modes of operation are first described in detail. Subsequently, the modelling of the hybrid shipboard power system using the MATLAB/Simulink platform is done. Load-changes are applied to this system in order to investigate the transient effects particularly focusing on the system voltage and frequency caused by varying the magnitudes and types of loads that occur in the different modes of a hybrid ships operation. This study has attempted to find the nature of the load as well as the hybrid ship operating modes that have a greater effect on the voltage and frequency transient conditions resulting from load variations. These findings help determine the suitable operating mode of a hybrid ship in the different loading scenarios at sea so as to minimise the voltage and frequency fluctuations encountered during the transient period.

Human-centred design knowledge into maritime engineering education; theoretical framework

Abstract Maritime designers engaged in the ship design process seem to be fairly unaware about human factors (HF), human-centred design (HCD) and the operational issues that ships’ crew are facing during their sea time. This is likely due to the combined effect of poor maritime HF education in maritime design engineering courses and poor ‘post-design’ contact with those who work onboard the ships. In order to address this issue, recent research studies suggest focusing on transferring HF/HCD knowledge to maritime design engineering students’ education in a more targeted, engineering-oriented fashion. This paper presents a theoretical framework and its proposed application to facilitate the maritime design engineering undergraduates to learn HF/HCD concepts and apply them during design process. The proposed framework is developed by connecting Problem-Based Learning and Peer-Led Team Learning student-centred pedagogies with Vygotsky’s Zone of Proximal Development theory that is central to Vygotsky’s sociocultural theory. The final-year design project unit of the Bachelor of engineering degree at Australian Maritime College is chosen to operationalise the proposed framework through a Participatory Action Research methodological framework, which is considered appropriate to study the effectiveness of a teaching intervention.

The application of signal processing techniques for real-time monitoring of the dynamic stability of a ship via its motion responses

Significant changes of stability at sea can lead to dangerous situations and eventually stability failure. Despite its importance, the current intact stability criteria do not evaluate the motion responses of a vessel. More recently, the International Maritime Organization has identified phenomena in seaways responsible for stability failures. These phenomena can cause large roll angles and/or accelerations that can endanger ships due to critical stability situations in waves. The measurement of waves while a ship is underway is a major challenge, but ship motion is a good reflection of the wave characteristics and can be captured. Signal processing techniques are used in the detection and estimation of the influential parameters of a wave through the analysis of motion responses. Some variables of the system can be detected by spectral analysis of heave and pitch responses. These variables are the peak wave frequencies and associated magnitudes which can cause a high roll motion when similar to the roll natural frequency. The instantaneous frequency present in the signal is revealed through spectral analysis of short-time Fourier transforms in less than a minute. The instantaneous frequency is a parameter of practical importance which can be used in decision-making processes to avoid high roll motions.