scholarly journals VISIR-I.b: waves and ocean currents for energy efficient navigation

2019 ◽  
Author(s):  
Gianandrea Mannarini ◽  
Lorenzo Carelli

Abstract. VISIR-I.b, the latest development of the ship routing model published in Mannarini et al. (2016a), is here presented. The new model version targets large ocean-going vessels by accounting for both waves and ocean currents. In order to effectively use currents in a graph-search method, new equations are derived and validated versus analytical benchmarks. A case study is computed in the Atlantic Ocean, on a route from the Chesapeake Bay to the Mediterranean Sea and vice versa. Ocean analysis fields from data-assimilative models (for both ocean state and hydrodynamics) are employed. The impact of waves and ocean currents on transatlantic crossings is assessed through mapping of the spatial variability of the routes, analysis of their kinematics, distribution of the optimal voyage duration vs. its length, and impact on the Energy Efficiency Operational Indicator of the International Maritime Organization. It is distinguished between sailing with or against the main ocean current. The seasonal dependence of the savings is evaluated, indicating, for the featured case study, larger savings during the summer crossings and larger intra-monthly variability in winter. The monthly-mean savings sum up to values between 3 and 12 %, while the contribution of ocean currents is between 1 and 4 %. Also, several other ocean routes are considered, providing a pan-Atlantic scenario assessment of the potential gains in energy efficiency from optimal tracks and linking them to regional meteo-oceanographic features.

2019 ◽  
Vol 12 (8) ◽  
pp. 3449-3480 ◽  
Author(s):  
Gianandrea Mannarini ◽  
Lorenzo Carelli

Abstract. The latest development of the ship-routing model published in Mannarini et al. (2016a) is VISIR-1.b, which is presented here. The new version of the model targets large ocean-going vessels by considering both ocean surface gravity waves and currents. To effectively analyse currents in a graph-search method, new equations are derived and validated against an analytical benchmark. A case study in the Atlantic Ocean is presented, focussing on a route from the Chesapeake Bay to the Mediterranean Sea and vice versa. Ocean analysis fields from data-assimilative models (for both ocean state and hydrodynamics) are used. The impact of waves and currents on transatlantic crossings is assessed through mapping of the spatial variability in the tracks, an analysis of their kinematics, and their impact on the Energy Efficiency Operational Indicator (EEOI) of the International Maritime Organization. Sailing with or against the main ocean current is distinguished. The seasonal dependence of the EEOI savings is evaluated, and greater savings with a higher intra-monthly variability during winter crossings are indicated in the case study. The total monthly mean savings are between 2 % and 12 %, while the contribution of ocean currents is between 1 % and 4 %. Several other ocean routes are also considered, providing a pan-Atlantic scenario assessment of the potential gains in energy efficiency from optimal tracks, linking them to regional meteo-oceanographic features.


2019 ◽  
Vol 111 ◽  
pp. 03028
Author(s):  
Nazanin Moazzen ◽  
Mustafa Erkan Karagüler ◽  
Touraj Ashrafian

Energy efficiency of existing buildings is a concept to manage and restrain the growth in energy consumption and one of the crucial issues due to the magnitude of the sector. Educational buildings are in charge of about 15% of the total energy consumption of the non-residential building sector. However, not only operational but also embodied energy of a building should be reduced to get the overall benefits of energy efficiency, where, using energy efficient architectural measures and low emitting materials during every retrofit action can be a logical step. The majority of buildings in Turkey and EU was built earlier than the development of the energy efficiency in the construction sector, hence, without energy retrofit, consume an enormous amount of energy that can be averted significantly by the implementation of some even not advanced retrofit measures. Furthermore, demolishing of a building to construct a new one is not a rational approach concerning cost, time and environmental pollution. The study has been focused on the impact assessment of the various architectural scenarios of energy efficiency upgrading on the Life Cycle Energy Consumption (LCEC) and Life Cycle CO2 (LCCO2) emission. Within the scope of the study, a primary school building is selected to be analysed. Through analysis, the total embodied and operational energy use and CO2 emission regarding the life cycle phase of the building is quantitatively defined and investigated in the framework of life cycle inventory. The paper concentrates on the operation and embodied energy consumption arising from the application of a variety of measures on the building envelope. An educational building with low LCCO2 emissions and LCEC in Turkey is proposed. To exemplify the approach, contributions are applied to a case study in Istanbul as a representative school building. The primary energy consumption of the case study building is calculated with a dynamic simulation tool, EnergyPlus. Afterwards, a sort of architectural energy efficient measures is implemented in the envelope while the lighting and mechanical systems remain constant. The energy used in the production and transportation of materials, which are the significant parts of the embodied energy, are taken into account as well.


Author(s):  
Abdelrahman Arbi ◽  
Timothy O'Farrell ◽  
Fu-Chun Zheng ◽  
Simon C. Fletcher

Network densification by adding either more sectors per site or by deploying an overlay of small cells is always considered to be a key method for enhancing the RAN coverage and capacity. The impact of these two techniques on cellular network energy consumption is investigated in this chapter. The aim is to find an energy efficient deployment strategy when trading-off the order of sectorisation with the intensity of small cell densification. A new enhanced base station power consumption model is presented, followed by a novel metric framework for the evaluation of the RAN energy efficiency. The use of the power model and the proposed metrics is demonstrated by applying them to a RAN case study when the two techniques are used to improve the network capacity. In addition, the chapter evaluates the amount of network energy efficiency improvement when various adaptive sectorisation schemes are implemented. The results show that the strategy of adding more sectors is less energy efficient than directly deploying an overlay of small cells, even when adaptive sectorisation is implemented.


2021 ◽  
Vol 11 (13) ◽  
pp. 6005
Author(s):  
Daniel Villanueva ◽  
Moisés Cordeiro-Costas ◽  
Andrés E. Feijóo-Lorenzo ◽  
Antonio Fernández-Otero ◽  
Edelmiro Miguez-García

The aim of this paper is to shed light on the question regarding whether the integration of an electric battery as a part of a domestic installation may increase its energy efficiency in comparison with a conventional case. When a battery is included in such an installation, two types of electrical conversion must be considered, i.e., AC/DC and DC/AC, and hence the corresponding losses due to these converters must not be forgotten when performing the analysis. The efficiency of the whole system can be increased if one of the mentioned converters is avoided or simply when its dimensioning is reduced. Possible ways to achieve this goal can be: to use electric vehicles as DC suppliers, the use of as many DC home devices as possible, and LED lighting or charging devices based on renewables. With all this in mind, several scenarios are proposed here in order to have a look at all possibilities concerning AC and DC powering. With the aim of checking these scenarios using real data, a case study is analyzed by operating with electricity consumption mean values.


Author(s):  
Rade M. Ciric ◽  
Sasa N. Mandic

AbstractThe Republic of Serbia must make significant efforts to promote and exploit renewable energy sources and increase energy efficiency in all energy sectors to ensure energy security and economic competitiveness, reduce the negative impact on the environment from energy production and use, and contribute to global efforts to reduce greenhouse gases. Within the paper several issues of integration of recently realized CHP plant are introduced and discussed. Firstly, the legal and energy policy issues in the Republic of Serbia regarding connecting CHP to the grid are presented. The challenges and technical solutions for CHP connection to the grid, as well as power quality issues and the role of the CHP plant during the restoration of power supply during the maintenance of the substation and unplanned loss of high voltage supply, are presented and discussed. Finally, the impact of prospective massive integration of CHP on the energy balance and CO2 emission reduction in the province of Vojvodina in Serbia is investigated and discussed. Since it is the first CHP plant realized in Serbia, it is crucial that experience be shared to all potential stakeholders in the future energy efficiency projects.


Author(s):  
Luke Phillipson ◽  
Yi Li ◽  
Ralf Toumi

AbstractThe forecast of tropical cyclone (TC) intensity is a significant challenge. In this study, we showcase the impact of strongly coupled data assimilation with hypothetical ocean currents on analyses and forecasts of Typhoon Hato (2017). Several observation simulation system experiments were undertaken with a regional coupled ocean-atmosphere model. We assimilated combinations of (or individually) a hypothetical coastal current HF radar network, a dense array of drifter floats and minimum sea-level pressure. During the assimilation, instant updates of many important atmospheric variables (winds and pressure) are achieved from the assimilation of ocean current observations using the cross-domain error covariance, significantly improving the track and intensity analysis of Typhoon Hato. As compared to a control experiment (with no assimilation), the error of minimum pressure decreased by up to 13 hPa (4 hPa / 57 % on average). The maximum wind speed error decreased by up to 18 knots (5 knots / 41 % on average). By contrast, weakly coupled implementations cannot match these reductions (10% on average). Although traditional atmospheric observations were not assimilated, such improvements indicate there is considerable potential in assimilating ocean currents from coastal HF radar, and surface drifters within a strongly coupled framework for intense landfalling TCs.


2019 ◽  
Vol 12 (8) ◽  
pp. 2201-2213
Author(s):  
Josefin Borg ◽  
Hannes von Knorring

AbstractThis article explores the complexities of establishing knowledge-sharing practices between organizations through a case study of the creation of a database for energy efficiency measures relevant to the shipping sector. As researchers and policy-makers tend to point towards knowledge sharing and collaboration as means towards a more energy-efficient society, there is a need to better understand the knowledge sharing practices in such initiatives. The study is based upon extensive fieldwork where the first author was recruited to a collaborative network on energy efficiency in the shipping sector, to aid in the development of the collaboration while carrying out participatory-observational research in an ethnographic tradition. The study highlights the need to maintain realistic expectations for new knowledge-sharing collaborations, and the necessity to allow such arrangements to develop over time.


2014 ◽  
Vol 548-549 ◽  
pp. 1815-1819 ◽  
Author(s):  
Xiao Chun Qin ◽  
She Gang Shao ◽  
Yi Shen

Green lighting technology has the advantages of energy efficiency, friendly environment, safety and comfort. Based on the introduction of green lighting technology, taken the Mt. Lushan West Sea tourist highway service as the case study, we analyzed light guide illumination, the optimum use of natural light and energy efficient lighting respectively from the aspects of technical characteristics and the specific highway service application. We finally made the economic analysis in the energy savings of green lights in the highway service, and the result showed that through the use of green lighting systems Mt. Lushan West Sea tourist highway service could save electricity and reduce operating costs 134,700 Yuan per year.


2017 ◽  
Vol 9 (4) ◽  
pp. 227-255 ◽  
Author(s):  
Sébastien Houde ◽  
Joseph E. Aldy

Through an evaluation of the 2009 Recovery Act's State Energy Efficient Appliance Rebate Program, this paper examines consumers' response to energy efficiency rebates. The analysis shows that 70 percent of consumers claiming a rebate were inframarginal and an additional 15 percent–20 percent of consumers simply delayed their purchases by a few weeks. Consumers responded to rebates by upgrading to higher quality, but less energy-efficient models. Overall the impact of the program on long-term energy demand is likely to be small. Measures of government expenditure per unit of energy saved are an order of magnitude higher than estimates for other energy efficiency programs. (JEL D12, H31, H71, Q48)


2014 ◽  
Author(s):  
David Jia ◽  
Madhusuden Agrawal ◽  
Jim Malachowski

Buoyancy modules are widely used in offshore and subsea fields, such as on pipelines, risers, umbilicals, and ROVs, etc. in operation and installation. Accidental release of subsea buoyancy modules due to broken or damaged parts may pose a potential risk and hazard to offshore vessels, floating platforms and risers & surrounding umbilicals. A released buoyancy module rises and may collide with any floating structures or pipes above it. For offshore and subsea field development, it is important to assess such potential risk to offshore vessels, floating platforms, and risers & umbilicals around them. Accurate prediction of the trajectory and the impact speed of the released buoyancy module is the key component for risk assessment in offshore and subsea field development. This paper presents a Computational Fluid Dynamics (CFD) solution for prediction of the trajectory and velocity of the released buoyancy modules from subsea. Six Degree of Freedom (DOF) rigid body motion of buoyancy module is modeled using an efficient moving mesh approach in transient CFD simulation. The effect of ocean currents at different water depths is considered in the motion of buoyancy modules. This methodology has potential applications in many areas, such as, offshore vessel and floating platform protection, riser and umbilical protection, offshore and subsea field planning and layout, etc. This transient CFD approach has been successfully implemented on typical buoyancy modules and demonstrated effect of ocean currents on the trajectory of the buoyancy modules. Hydrostatic forces, 6DOF motion and the velocities of the buoyancy module were predicted with different ocean current velocities. The approach proposed in this paper captures the physics of released buoyance module in transient CFD and provides a practical tool for determining the trajectory and velocity of the released buoyancy modules from subsea and quantifying the risk for such an event. It can potentially be used for assessing the risk to offshore vessels and floating platforms, risers and umbilicals, as well as for offshore and subsea field planning and layout.


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