A method for constructing a sail-assisted energy-saving evaluation index system

Abstract

The application discloses a kind of sail navigation energy-saving evaluation index system construction method, including determining sail type, ship type, obtain global trade route information, wind field data, ship information, with sail navigation ship as object, establish the motion model of sail navigation ship, according to wind field data acquisition wind speed wind direction space-time distribution characteristics and construct wind power resource probability matrix, calculate the propulsion power that sail can provide in route and the energy-saving effect of sail for sail navigation ship, establish sail navigation ship energy-saving index system and the weight of each index, determine target ship and obtain total weight, calculate the energy-saving effect of target ship after installing sail in the route of this ship, track band or global shipping range, according to energy-saving effect and total weight determine whether target ship needs to install sail. The proportion of sail energy-saving effect in the ship equipped with sail navigation equipment in the target sail navigation ship in its operating route, global sea area range, all routes in the world can be accurately calculated.

Description

Technical Field

[0001] This invention relates to the field of ship energy efficiency management technology, and in particular to a method for constructing an energy-saving assessment index system for sail-assisted navigation. Background Technology

[0002] For modern sailing ships, the advanced development of computer control technology has made intelligent control of sails under different wind conditions possible. Furthermore, advancements in satellite and other meteorological monitoring technologies have made adjusting sail application based on weather forecasts along the ship's route feasible. Using sails for navigation will become an important development direction for future environmentally friendly ships. However, current technology cannot quantitatively describe the energy-saving effect on ships on a specific global route, nor can it quantitatively calculate the proportion of energy-saving effects of sails among suitable ships for installation on sail-assisted navigation systems across the entire global sea area and all global routes. Therefore, when applying sail-assisted navigation, the energy-saving situation cannot be intuitively described, and a quantitative proportion cannot be given to evaluate the impact of the sail-assisted navigation system on energy-saving performance. Summary of the Invention

[0003] This invention provides a method for constructing an energy-saving evaluation index system for sail-assisted navigation, in order to overcome the above-mentioned technical problems.

[0004] A method for constructing an energy-saving evaluation index system for sail-assisted navigation, including:

[0005] Step 1: Determine the type of sail to be assessed for energy efficiency and the type of vessel that can be fitted with sails. Obtain global trade route information, wind farm data, and vessel information. The global trade route information includes vessel type, vessel model, port of origin, intermediate ports, port of destination, cargo volume, and trade volume.

[0006] Step 2: Determine the sail type as a wing sail. Taking the sail-assisted vessel as the object, establish a motion model of the sail-assisted vessel through force analysis and coordinate transformation. This motion model is used to calculate the main engine power of the sail-assisted vessel, and based on the main engine power, calculate the effective power of the sail-assisted vessel.

[0007] The navigation area is determined based on the route information of the sail-assisted vessel, and the spatiotemporal distribution characteristics of wind speed and direction are obtained based on the wind field data corresponding to the navigation area.

[0008] Based on the spatiotemporal distribution characteristics of wind speed and direction, a wind resource probability matrix is ​​constructed for the route of sail-assisted vessels. The propulsion power that the sails can provide within the route is then calculated based on the wind resource probability matrix.

[0009] The energy-saving effect of sails on sail-assisted navigation vessels within a course is calculated based on the ship's effective power and the propulsion power that sails can provide.

[0010] Step 3: Establish an energy-saving index system for sail-assisted navigation vessels, and determine the weight of each index in the energy-saving index system for sail-assisted navigation vessels.

[0011] Step 4: Determine the target vessel. Calculate the sum of the weights of the corresponding indicators for the target vessel according to the energy-saving index system for sail-assisted navigation, and express it as the total weight. Calculate the energy-saving effect of installing sails on the target vessel within its own route, track zone, or global shipping range. Determine whether the target vessel needs to install sails based on the energy-saving effect and the total weight.

[0012] Preferably, the energy-saving effect of the sail on the sail-assisted navigation vessel within the route is calculated based on the ship's effective power and the propulsion power provided by the sail, using formula (1) to calculate the energy-saving effect η. w ,

[0013]

[0014] Among them, P H P is the effective power of a ship during navigation. W The propulsion power that a sail can provide.

[0015] Preferably, the propulsion power provided by the sail is calculated according to formula (2).

[0016]

[0017] Among them, V S For the ship's reference speed, F i.j Let i be the total thrust of the ship's sails, and i and j be the index values ​​of the thrust load matrix, i = 1, 2, ... 26, j = 1, 2, ... 72.

[0018] Preferably, the energy-saving index system for sail-assisted navigation vessels includes vessel type, vessel tonnage, cargo volume, navigation area, proportion of sea areas and routes, wind field data of the sea area where the route is located, voyage distance, and aerodynamic characteristics of the sails.

[0019] Preferably, determining whether a target vessel needs to install sails based on energy-saving effect and total weight involves calculating the proportion of total sail energy-saving effect of the target vessel according to formula (3). If the proportion meets the threshold, it indicates that the target vessel is suitable for installing sails; otherwise, it indicates that the target vessel is not suitable for installing sails.

[0020] H = η w *P (3)

[0021] Where P is the total weight, η w For energy-saving effect, H represents the proportion of total sail energy-saving effect.

[0022] This invention provides a method for constructing an energy-saving evaluation index system for sail-assisted navigation. It can not only quantitatively describe the energy-saving effect of sails on the target sail-assisted vessel on its operating route, but also quantitatively describe the proportion of sail energy-saving effect among vessels suitable for installing sail-assisted navigation equipment in global sea areas and on all global routes. It can even change the classification benchmark of the index to evaluate the economic efficiency, practicality, and effectiveness of the sail effect of vessels equipped with sail-assisted navigation equipment, and also verify the feasibility of installing sails on vessels that have not yet been equipped with sail-assisted navigation equipment. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of the method of the present invention;

[0025] Figure 2 This is the corresponding structural block diagram of the present invention;

[0026] Figure 3 This is the corresponding architecture diagram of the present invention;

[0027] Figure 4 This is a spatiotemporal analysis of the wind field in the Bay of Bengal waters traversed by the target route of this invention;

[0028] Figure 5 This is a spatiotemporal distribution pattern diagram of wind field data from three flight segments in 2021, as an example of the present invention;

[0029] Figure 6 This is a force analysis diagram of the sail of this invention;

[0030] Figure 7 This is a diagram illustrating the composition of the indicator system of this invention;

[0031] Figure 8 This is a hierarchical index division diagram of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Figure 1 This is a flowchart of the method of the present invention, as shown below. Figure 1 As shown, the method in this embodiment may include:

[0034] Step 1: Determine the type of sail to be assessed for energy efficiency and the type of vessel that can be fitted with sails. Obtain global trade route information, wind farm data, and vessel information. The global trade route information includes vessel type, vessel model, port of origin, intermediate ports, port of destination, cargo volume, and trade volume.

[0035] Step 2: Determine the sail type as a wing sail. Taking the sail-assisted vessel as the object, establish a motion model of the sail-assisted vessel through force analysis and coordinate transformation. This motion model is used to calculate the main engine power of the sail-assisted vessel, and based on the main engine power, calculate the effective power of the sail-assisted vessel.

[0036] The navigation area is determined based on the route information of the sail-assisted vessel, and the spatiotemporal distribution characteristics of wind speed and direction are obtained based on the wind field data corresponding to the navigation area.

[0037] Based on the spatiotemporal distribution characteristics of wind speed and direction, a wind resource probability matrix is ​​constructed for the route of sail-assisted vessels. The propulsion power that the sails can provide within the route is then calculated based on the wind resource probability matrix.

[0038] The energy-saving effect of sails on sail-assisted navigation vessels within a course is calculated based on the ship's effective power and the propulsion power that sails can provide.

[0039] Step 3: Establish an energy-saving index system for sail-assisted navigation vessels, and determine the weight of each index in the energy-saving index system for sail-assisted navigation vessels.

[0040] Step 4: Determine the target vessel. Calculate the sum of the weights of the corresponding indicators for the target vessel according to the energy-saving index system for sail-assisted navigation, and express it as the total weight. Calculate the energy-saving effect of installing sails on the target vessel within its own route, track zone, or global shipping range. Determine whether the target vessel needs to install sails based on the energy-saving effect and the total weight.

[0041] Based on the above scheme, this invention can not only quantitatively describe the energy-saving effect of the sails of the target sail-assisted vessel on its operating route, but also quantitatively describe the proportion of the energy-saving effect of the sails of the target sail-assisted vessel among vessels suitable for installing sail-assisted equipment in the global sea area and on all global routes. It can even change the classification criteria of the indicators to evaluate the economic efficiency, practicality, and effectiveness of the sail effect of vessels equipped with sail-assisted equipment, and also verify the feasibility of installing sails on vessels that have not yet been equipped with sail-assisted equipment.

[0042] Specifically, this embodiment provides detailed information on the method for constructing the indicator system, including:

[0043] First, let's look at the background of this invention: To address greenhouse gas emissions and climate change, the United Nations has established a global policy framework for climate change, primarily based on the Framework Convention on Climate Change and the Paris Agreement. The Paris Agreement, reached in 2015, set a target of limiting global warming to 2°C this century, and all contracting parties have actively formulated greenhouse gas emission reduction targets and action plans. In 2018, the International Maritime Organization (IMO) released its initial greenhouse gas emission reduction strategy, outlining medium- and long-term emission reduction targets: a reduction of at least 40% in carbon intensity by 2035, a target of 70% reduction in carbon intensity by 2050, and a reduction of at least 50% in total greenhouse gas emissions compared to 2008 levels. Research reports indicate that the shipping industry is far from meeting the IMO's 2050 emission reduction target. To achieve these medium- and long-term emission reduction targets, the IMO has proposed that developing and utilizing clean energy is a crucial countermeasure.

[0044] To address the issue of energy conservation and emission reduction in shipping, the shipping industry has proposed various measures to reduce carbon dioxide emissions from ships, with the utilization of clean energy sources such as wind power being one of the effective measures. Wind energy is a clean and renewable energy source with abundant global reserves, inexhaustible and readily available. The application of wind energy in ships has a long history. With the continuous development of science and technology, modern wind-assisted propulsion technology is no longer a simple manual operation, but an automated, more economical, and safer propulsion method. Furthermore, due to the good aerodynamic characteristics and large thrust coefficient of airfoil sails, wind-assisted ships can effectively utilize wind energy to reduce ship fuel consumption, decrease carbon dioxide emissions, and improve ship energy efficiency.

[0045] Considering the differences in emission reduction due to varying operating speeds, ship types, weather conditions, and routes, the CO2 emission reduction effect achieved by wind propulsion technology exhibits some instability. Current research estimates the emission reduction potential of wind power technology on ships at approximately 1-50% CO2 reduction. Therefore, sail-assisted navigation can effectively improve ship energy efficiency and achieve energy conservation and emission reduction. Meanwhile, different sails have different characteristics, with rigid wing sails exhibiting the best aerodynamic performance and promising application prospects. For a specific sail, the thrust it provides depends on the wind direction and speed conditions. According to wind tunnel test data, the lift coefficient provided by the sail varies under different wind directions and speeds, resulting in variations in the thrust provided. How to evaluate the sail's propulsion effect based on changes in wind speed and direction along the ship's target route, thereby maximizing energy conservation and emission reduction for sail-assisted navigation and improving the ship's greenness, is an important research direction.

[0046] The effectiveness of emission reduction should accurately take into account the ship's current condition, the aerodynamic characteristics of the sails, and the meteorological characteristics of navigation. For the same route, due to the uncertainty of ocean wind fields, the wind field distribution of a sail-assisted vessel may differ at different times and in different locations. Furthermore, due to the aerodynamic characteristics of the sails, the auxiliary thrust generated by the sails varies with the ship's relative wind angle. Therefore, for the same ship, on the same route, with different airfoils, at different times, and under different directions, the spatiotemporal distribution of wind resources will differ, resulting in different propulsion effects from the sails, thus affecting the energy conservation and emission reduction effects. In conclusion, when analyzing the energy conservation and emission reduction effects of sail-assisted vessels, a comprehensive analysis is needed, considering the ship's motion state, the aerodynamic characteristics of the sails, route information, and the available wind field in the route area.

[0047] If an evaluation system is established, by formulating reasonable impact indicators and creating an energy-saving effect evaluation mechanism, the energy-saving effect can be calculated. The final calculation results can quantitatively analyze the energy-saving effect of a ship equipped with sails. Then, values ​​are assigned according to the actual situation of the target sail-assisted navigation ship, including ship type, tonnage, cargo volume, navigation area, proportion of sea areas and routes, wind field data of the sea area where the route is located, voyage distance, and aerodynamic characteristics of the sails. These data are comprehensively considered, and weights are objectively allocated. The energy-saving effect parameters obtained by the evaluation system are then multiplied by the weight ratios to obtain a final energy-saving effect weight. This allows for a reasonable evaluation of the comprehensive performance of the sail-assisted navigation system. The system can also evaluate the economy, practicality, and effectiveness of the sail effect on ships equipped with sail-assisted navigation equipment, and verify the feasibility of adding sails to ships that have not yet been equipped. Therefore, establishing a complete evaluation index system for sail-assisted navigation ships is of great significance for promoting sail-assisted navigation ships and improving their technology.

[0048] Based on the background information above, this embodiment provides a detailed solution, including...

[0049] Step 1: Determine the type of sail to be assessed for energy conservation and the type of vessel on which the sail can be installed. In the early stages of system construction, it is necessary to determine the vessel's sail information. This invention compares the sails with several common types, analyzing and explaining the sail placement, number of sails, sail size, and aerodynamic characteristics. It was found that airfoil sails have a simple structure, are easy to control, have low cost, and offer a relatively ideal overall energy-saving effect. Therefore, this patent selects airfoil sails as the target sail type for research.

[0050] To facilitate comparisons of energy-saving effects between different ship types, between different deadweight tonnages of the same ship type, and between different ship types of the same deadweight tonnage, and to further investigate the suitability of installing sails on ships to utilize wind power for propulsion, it was determined that the installation of sail-assisted navigation systems must not adversely affect other equipment and systems on board. Feasibility, safety, and energy efficiency must be guaranteed; therefore, the selection of typical ships for sail-assisted navigation must adhere to certain safety and reliability principles. Based on these principles, large oil tankers, bulk carriers, and LNG carriers were selected as suitable typical ships for installing sail-assisted navigation systems.

[0051] This involves acquiring global trade route information, wind farm data, and vessel information. The global trade route information includes vessel type, vessel type, port of origin, intermediate ports, port of destination, cargo volume, and trade volume. Global trade routes form the basis for evaluating the energy efficiency of ships equipped with sails. Suitable vessels for installing sail-assisted navigation equipment include bulk carriers, oil tankers, and LNG carriers. These are categorized by global vessel type. To calculate the energy efficiency of sail-assisted navigation and to compare energy efficiency across different vessel types, deadweights, routes, and paths, global trade route information is acquired, including vessel type, vessel type, port of origin, intermediate ports, port of destination, cargo volume, and trade volume.

[0052] When classifying ships by type and model, it is important to categorize them according to their cargo volume. This is because a ship may load and unload cargo at intermediate ports during a single shipping operation. If classification is based on deadweight while ignoring changes in cargo volume at intermediate ports, errors will occur in the final efficiency calculation. Therefore, ships are classified by cargo volume to eliminate this error. The reason for recording trade volume is that ships engaged in high-volume trade operations on a particular route are generally more energy-efficient than the same type of ship engaged in low-volume trade operations on the same route.

[0053] From a geographical perspective, the overall distribution pattern of international shipping routes based on the number of routes is relatively clear, mainly concentrated in North America, the Mediterranean, and Northern Europe. However, these routes generally exhibit a typical "point-line" structure, involving numerous factors such as route density, route duration, port of origin, ports of call, route network structure, and port competition. It is difficult to grasp the characteristics and patterns of route distribution solely from a quantitative perspective. From an academic research perspective, there are currently few studies that comprehensively and deeply explore the distribution patterns and network structure characteristics of international shipping routes. Therefore, this study reviewed the characteristics of major shipping routes in the Pacific, Atlantic, and Indian Oceans, as well as the world's major shipping routes, wind resources, and the main types of vessels used in these routes, comprehensively analyzing the basic characteristics of global shipping route distribution.

[0054] Step 2: Determine the sail type as a wing sail. Taking a sail-assisted vessel as the object, establish a motion model of the sail-assisted vessel through force analysis and coordinate transformation. This motion model is used to calculate the main engine power and effective power of the sail-assisted vessel.

[0055] Specifically, shipping routes traverse numerous vast sea areas rich in wind resources. With the addition of sail-assisted navigation equipment, wind fields cease to be, or are not entirely, an adverse factor for navigation. Available wind within the ship's tolerance range becomes an auxiliary thrust. By controlling the sail-assisted navigation equipment, the auxiliary thrust of the ocean wind field can be superimposed on the planned route, thus making the ocean wind field a resource providing auxiliary thrust. Accurately understanding the distribution characteristics of the wind field along the route is fundamental to utilizing ocean wind resources. After completing the above work, energy-saving assessments can be conducted on sail-assisted vessels on different routes for different vessels. First, a sail-assisted vessel is selected as the research object, and data such as ship parameters, route information, and meteorological information are obtained.

[0056] The navigation area is determined based on the route information of sail-assisted vessels, and the spatiotemporal distribution characteristics of wind speed and direction are obtained based on the corresponding wind field data, thereby enabling wind resource analysis of the vessel's navigation area.

[0057] A wind resource probability matrix is ​​constructed along the route of the sail-assisted vessel. The propulsion power that the sail can provide along the route is calculated based on the wind resource probability matrix. The propulsion power that the sail can provide is calculated according to formula (1).

[0058]

[0059] Among them, V S For the ship's reference speed, F i.j Let i be the total thrust of the ship's sails, and i and j be the index values ​​of the thrust load matrix, i = 1, 2, ... 26, j = 1, 2, ... 72.

[0060] The energy-saving effect of the sail on a sail-assisted vessel within a course is calculated based on the ship's effective power and the propulsion power provided by the sail. This energy-saving effect η is calculated according to formula (2). w ,

[0061]

[0062] Among them, P H P is the effective power of a ship during navigation. W The propulsion power that a sail can provide.

[0063] Step 3: Establish an energy-saving indicator system for sail-assisted navigation vessels. This system includes vessel type, tonnage, cargo volume, navigation area, percentage of sea areas and routes, wind field data for the sea areas where the routes are located, voyage distance, and aerodynamic characteristics of the sails. Specifically, this energy-saving indicator system, through the total sum and analysis of indicators, can comprehensively, objectively, and accurately detect energy conservation and emission reduction, effectively evaluate the effects of energy conservation and emission reduction, and provide data support, thus providing a basis for deciding whether a vessel needs to install a sail-assisted navigation system. Through data research on the qualitative and quantitative indicators in the indicator system, the situation of each indicator in the energy conservation and emission reduction work of sail-assisted navigation vessels can be reflected relatively objectively. This not only shows the advantages of energy conservation and emission reduction work but also exposes its weaknesses, pointing the way for a deeper understanding of the key points of energy conservation and emission reduction work and serving as a starting point for further improvement of energy conservation and emission reduction efforts. It is evident that establishing a comprehensive and detailed ship energy conservation assessment system is beneficial for understanding the practical work of energy conservation and emission reduction in sailing vessels. At the same time, the magnitude of data for each indicator can also serve as a refinement and supplement to determine the key points of energy conservation and emission reduction work. This provides a reliable basis for strengthening weak links in energy conservation and emission reduction work and detailing them into specific tasks. It also helps enterprises, based on their own characteristics, maintain their advantageous energy conservation and emission reduction indicators while simultaneously addressing weak links, thus determining the key points of energy conservation and emission reduction work and ensuring that all energy conservation and emission reduction indicators meet or exceed the targets.

[0064] The weights of each indicator in the energy-saving index system for sail-assisted navigation vessels are determined. The weight P is assigned a value based on the actual situation of the target sail-assisted navigation vessel, including vessel type, vessel tonnage, cargo volume, navigation area, proportion of sea areas and routes, wind field data of the sea area where the route is located, voyage distance, and aerodynamic characteristics of the sails. Taking into account the above data, the weights are objectively allocated based on actual conditions and experience.

[0065] Step 4: Determine the target vessel. Calculate the sum of the weights of the corresponding indicators for the target vessel according to the energy-saving index system for sail-assisted navigation, and express it as the total weight. Calculate the energy-saving effect of installing sails on the target vessel within its own route, track zone, or global shipping range. Determine whether the target vessel needs to install sails based on the energy-saving effect and the total weight.

[0066] The determination of whether a target ship needs to install sails based on energy-saving effect and total weight is as follows: the proportion of total sail energy-saving effect of the target ship is calculated according to formula (3). If the proportion meets the threshold, it means that the target ship is suitable for installing sails; otherwise, it means that the target ship is not suitable for installing sails.

[0067] H = η w *P (3)

[0068] Where P is the total weight, η wFor energy-saving effect, H represents the proportion of total sail energy-saving effect.

[0069] Specifically, the following is a detailed implementation process of the method of the present invention, such as... Figure 2 The diagram shown is a structural diagram. Figure 3 The following is an architecture diagram:

[0070] Step 1: Obtain the main parameter information of the sail, select the type of ship suitable for adding sails, obtain relevant information such as the ship's route and trade volume, and extract wind resources from the sailing path;

[0071] 1. In the early stages of system construction, this invention first explains the requirements for sail applications. The following are the evaluation criteria for ship sails by the U.S. Maritime Agency, which serve as the standard for testing the performance of ship sails:

[0072] (1) Economic feasibility: the sail should be able to provide a large propulsion force, the sail has a wide range of use conditions and saves a lot of fuel, thus achieving an ideal return on investment.

[0073] (2) Simplified structure: The structure of the sail should be simple and regular with few moving parts.

[0074] (3) Durability: The sail should be able to withstand various harsh sea conditions and have a low failure rate.

[0075] (4) Remote control: the sails can be controlled from the bridge.

[0076] (5) Automation: No additional crew is required to operate the sails.

[0077] (6) The installation of sails shall comply with the existing classification society specifications.

[0078] (7) It does not affect the loading and unloading of goods, and the position of the sail does not interfere with the hoisting of goods.

[0079] There are currently more than ten types of sails in the world. The working principles, aerodynamic performance, and mechanical structures of various sails are not entirely the same. They are mainly divided into kite sails, rotary sails, airfoil sails, and exhaust turbine sails.

[0080] First, the ship's sail information needs to be determined. This invention compares the sails with several common types, analyzes the sail shapes, and consults relevant literature. The selection of sail type and adjustment of sail angle should be determined according to the actual wind direction on the route. The following uses the China-Korea route as an example for specific explanation. For example, the China-Korea route experiences predominantly northerly and northwesterly winds in the first quarter, the frequency of various wind directions is not significantly different in the second quarter, the third quarter is mainly southerly and southwesterly winds (including winds in the vicinity of southerly and southwesterly winds), and the fourth quarter is dominated by northerly, northeasterly, and northwesterly winds. Therefore, in the first and fourth quarters, airfoil sails with better crosswind performance are suitable for better energy saving. In the second quarter, the wind distribution is even in all directions, and the energy saving effect of various sails is not significantly different during round-trip voyages. In the third quarter, the ship is basically sailing with or against the wind, so rotary sails or airfoil sails with better downwind performance are suitable for achieving better energy saving.

[0081] Furthermore, the paper analyzes and explains the arrangement, number, size, and aerodynamic characteristics of the sails, finding that airfoil sails are simple in structure, easy to control, low in cost, and have a relatively ideal overall energy-saving effect. Therefore, this patent selects airfoil sails as the sails to be installed on the target ship for research.

[0082] 2. To facilitate comparisons of energy-saving effects between different ship types, between different deadweight tonnages of the same ship type, and between different ship types of the same deadweight tonnage, and to further clarify that installing sails on ships can utilize wind energy to assist in propulsion, the installation of sail-assisted navigation systems must not adversely affect other equipment and systems on board. Feasibility, safety, and energy efficiency must be guaranteed; that is, the selection of typical ships for sail-assisted navigation must adhere to certain safety and reliability principles. Based on the above principles, large oil tankers, bulk carriers, and LNG carriers were selected as typical ships suitable for installing sail-assisted navigation systems.

[0083] 3. Next, global trade route information, wind field data, and vessel information are acquired. Global trade route information is the foundation for evaluating the energy efficiency of ships using sail-assisted navigation. Suitable vessels for installing sail-assisted navigation equipment include bulk carriers, oil tankers, and LNG carriers. These are categorized by global ship type. To calculate the energy efficiency of sail-assisted navigation and compare energy savings for each ship type, deadweight, route, and channel, global trade route information is acquired, including vessel type, vessel form, port of origin, intermediate ports, port of destination, cargo volume, and trade volume. When classifying vessel types and forms, it is important to categorize them by cargo volume. This is because a vessel may load and unload cargo at intermediate ports during a single shipping operation. Classifying by deadweight while ignoring changes in cargo volume at intermediate ports will introduce errors in the final efficiency calculation. Therefore, vessels are categorized by cargo volume to eliminate this error. The reason for recording trade volume is that ships carrying out large-volume trade operations on a certain route are more economically efficient and energy-saving than ships carrying the same type of ships on the same route carrying small-volume trade operations.

[0084] From a geographical perspective, the overall distribution pattern of international shipping routes based on the number of routes is relatively clear, mainly concentrated in North America, the Mediterranean, and Northern Europe. However, these routes generally exhibit a typical "point-line" structure, involving numerous factors such as route density, route duration, port of origin, ports of call, route network structure, and port competition. It is difficult to grasp the characteristics and patterns of route distribution solely from a quantitative perspective. From an academic research perspective, there are currently few studies that comprehensively and deeply explore the distribution patterns and network structure characteristics of international shipping routes. Therefore, this study reviewed the characteristics of major shipping routes in the Pacific, Atlantic, and Indian Oceans, as well as the world's major shipping routes, wind resources, and the main types of vessels used in these routes, comprehensively analyzing the basic characteristics of global shipping route distribution.

[0085] Information on global trade routes can be obtained through various means, including shipping websites, classification societies, shipping websites, and shipping companies. Taking ShippingNet as an example, it was one of the earliest websites in China to provide ship location monitoring. It obtains dynamic ship positions through various methods such as shore-based AIS, satellite AIS, Inmarsat-C, and Inmarsat D+, and uses WebGIS technology to display this information intuitively and conveniently on electronic nautical charts. ShippingNet allows for real-time ship positioning. Depending on the ship's speed, the position update frequency ranges from a few seconds to several minutes. Ships outside the coverage area of ​​AIS base stations retain their position from the last received signal. Through AIS signals, ships continuously transmit two types of information: static information such as ship name, call sign, MMSI, IMO, ship type, length, and beam; and navigation status, draft, latitude and longitude, heading, speed, destination, and ETA.

[0086] Next, global wind field data is extracted. The marine meteorological data in this patent comes from the European Centre for Medium-Range Weather Forecasts (ECMWF) Generation 5 Reanalysis Data (ERA5).

[0087] Furthermore, ECMWF has cooperation agreements with Croatia, Iceland, Hungary, and Slovenia, and specific operational agreements with the World Meteorological Organization (WMO), the European Organisation for the Development of Meteorological Satellites (EUMETSAT), and the African Centre for the Development of Meteorological Applications (ACMAD). ECMWF also maintains extensive connections with meteorological forecasting agencies worldwide in the field of weather forecasting. ECMWF primarily provides 10-day medium-range numerical weather prediction (MLNR) products. Member states obtain these products through dedicated regional meteorological data communication networks and then formulate their own MNR forecasts. ECMWF also transmits some useful MNR products to all countries worldwide through a global communication network maintained by the WMO. Its model fully utilizes four-dimensional assimilated data, providing global wind field, temperature, and humidity forecasts for 20,911,680 points at a 40-kilometer grid density across 60 layers at an altitude of 65 kilometers. The dataset covers the period from 1979 to the present and includes meteorological data on the atmosphere, ocean waves, and land surface. Its temporal resolution is 6 hours (00:00, 06:00, 12:00, 18:00 UTC every day), and its planar resolution is up to 0.125° × 0.125°.

[0088] The marine meteorological data in this patent has a temporal resolution of 6 hours (00:00, 06:00, 12:00, and 18:00 UTC daily) and a planar resolution of 0.25° × 0.25°. The retrieved marine meteorological data includes wind field data in the U and V directions at a height of 10m, average pressure, and ocean surface temperature. Based on historical navigation data, wind field data for the corresponding navigation location is extracted in time units.

[0089] 4. Spatiotemporal interpolation is used for data extraction. Spatiotemporal interpolation is a method for estimating spatial data values ​​at unknown locations and times, typically based on the known spatial and temporal locations of data points. Spatiotemporal interpolation can be used in various fields, such as meteorology, environmental science, geographic information systems, and geology.

[0090] The purpose of spatiotemporal interpolation is to predict data values ​​at unknown locations and times using known data points. This process involves three main aspects: spatial location, time, and data values. Spatially, spatiotemporal interpolation methods typically use discrete point data, which have known x, y, and z coordinates in three-dimensional space. Temporally, spatiotemporal interpolation can be based on known time-series data to estimate spatial data values ​​for the future or back to the past.

[0091] Common types of spatiotemporal interpolation methods include Kriging interpolation, inverse distance weighted interpolation, triangular mesh interpolation, and regression analysis. These methods use different algorithms and mathematical models to estimate unknown spatial data values, and the most suitable method for the data type and distribution can be selected. This embodiment uses spatiotemporal interpolation to process downloaded data to obtain relevant data during ship navigation: based on the ship's sensor acquisition time and the corresponding ship's location, meteorological data for the ship's navigation area is interpolated in both time and space to obtain navigation environment data corresponding to the ship's spatiotemporal location.

[0092] In the analysis of wind resources, wind speed, wind direction, and wave height are three very important concepts, as they have a significant impact on ship operation and safety. Wind direction and wind speed are the two most important parameters describing the characteristics of wind. Wind speed refers to the speed at which air moves, that is, the distance that a unit of air particle travels. In general performance calculations, both instantaneous wind speed and average wind speed are the average values ​​of wind speeds within the windward area.

[0093] (1) Instantaneous wind speed, also known as effective wind speed, refers to the wind speed that actually has an effect, usually referring to the wind speed over a very short time interval (such as 1 second or a few seconds).

[0094] (2) Average wind speed is the average wind speed over a long period of time (such as 10 minutes or 1 hour). In fact, it is the average of multiple wind speed measurements over a relatively long period of time.

[0095] Wind direction refers to the direction in which the wind blows relative to a ship. In navigation, wind direction is crucial because it affects a ship's speed, direction, and stability. A ship's speed and direction are influenced by wind force; if the wind direction is the same as the ship's direction of travel, the ship's speed and direction will be boosted, while if the wind direction is opposite, the ship's speed and direction will be hindered. Furthermore, wind direction affects a ship's stability; if the wind is strong, the hull is more susceptible to crosswinds, leading to dangerous situations such as yaw or capsizing. Therefore, crew members need to take appropriate measures based on the wind direction to ensure safe navigation. Wave height refers to the height of waves on the ocean surface, commonly used to describe the size of ocean waves. Wave height is influenced by factors such as wind force, tides, and the Earth's rotation, and typically occurs in oceans and lakes. In navigation, wave height is an important indicator because it affects a ship's speed, stability, and comfort. If the wave height is high, the hull is more susceptible to impact from the waves, causing pitching and rolling, and may even lead to capsizing or damage. Furthermore, wave height also affects a ship's speed and energy consumption, as navigating in waves requires more fuel and energy. Therefore, during navigation, crew members need to closely monitor wave conditions and adjust speed and direction accordingly to ensure safe and stable navigation. Ship routes traverse numerous vast sea areas rich in wind resources. With the installation of sail-assisted navigation equipment, wind fields are no longer, or not entirely, an adverse factor for navigation; usable wind within acceptable limits becomes an auxiliary thrust. By controlling the sail-assisted navigation equipment, the auxiliary thrust of the ocean wind field can be superimposed on the planned route, thus making the ocean wind field a resource providing auxiliary thrust. Accurately understanding the distribution characteristics of wind fields along the route is fundamental to utilizing ocean wind resources. Therefore, analyzing and extracting the distribution characteristics of ocean wind resources is crucial.

[0096] The acquired meteorological data can be plotted and analyzed based on its time and location. For example, the spatiotemporal analysis of the wind field in the Bay of Bengal region traversed by the target route is as follows: Figure 4 As shown, abundant wind energy resources can increase sail thrust, thereby improving the energy efficiency of wind-assisted vessels. Therefore, environmental factor analysis is an important basis for optimizing the energy consumption of wind-assisted vessels. A wind rose chart, also known as a polar bar chart, is typically used to display the frequency of annular data distributions, such as wind direction and speed. Its basic idea is to divide the annular data into several sector regions, count the frequency of data within each region, and then use the angle of the sector region to represent the data proportion and the radius to represent the data frequency. Generally, wind rose charts are used when the annular data distribution is relatively uniform.

[0097] Taking the creation of a wind rose diagram as an example, firstly, the acquired wind direction, wind speed, and other data are imported into MATLAB for reading, and the corresponding data area is selected. Simple wind direction rose diagrams and wind speed rose diagrams can be drawn using MATLAB's built-in function `rose(thera, nbins)`, where `thera` represents wind direction or wind speed, and `nbins` represents the number of average intervals [0, 2*pi]. The wind rose diagram drawn using this function can only represent the distribution of wind direction frequency. If both wind direction and wind frequency need to be represented, then `wind_rose(D, I, varraygin)` needs to be used. In the syntax, `D` represents wind direction in degrees, `I` represents wind speed, and `varraygin` represents various control parameters. The drawn wind rose diagram can express both the frequency of wind direction and the range of wind speed based on color. Analysis of all sea areas reveals that the Bay of Bengal, the Arabian Sea, the Pacific Ocean, the Atlantic Ocean, the Arctic Ocean, and the South China Sea all exhibit obvious monsoon characteristics and abundant wind resources, suitable for sailing ships. Actual ship-based wind field measurement and analysis data also confirm this.

[0098] A box plot, also known as a box chart, is a graph used to display the distribution of a set of data. It shows the central tendency and dispersion of the data by plotting the minimum, first quartile, median, third quartile, and maximum value, and can also show outliers. A box plot typically consists of a rectangular box representing the quartiles of the data and a line segment representing the range of the data.

[0099] Box plots can be used to analyze wind field data to reveal the spatiotemporal distribution patterns of wind fields. Taking wind field data from three flight segments in 2021 as an example, the results are as follows: Figure 5 As shown in the box plot of the 2021 South China Sea wind resources weekly analysis, in terms of wind speed, the wind speed in the first 3 weeks and after week 50 was higher than at other times, even exceeding 10 m / s; at other times, the wind speed fluctuated around 5 m / s. Regarding wind direction angle, the wind direction angle was mainly below 100° from week 20 to week 38, and mostly stable at around 200° at other times of the year. During seasonal changes, such as week 38 to week 40, the wind direction fluctuated significantly.

[0100] In general, wind rose diagrams are suitable for visualizing circular data, while box plots are suitable for displaying non-circular data and for statistical analysis. Based on these methods, wind field information for various sea areas can be analyzed to infer whether it is suitable to install sails.

[0101] Step 2: Establish a mathematical motion model for the ship and analyze the forces acting on the ship aided by sails;

[0102] 1. For sail-assisted vessels, the propeller converts the received main engine output power into thrust to propel the vessel, while the sails also contribute auxiliary propulsion to reduce the main engine power output, thereby saving fuel consumption. Simultaneously, the vessel needs to overcome wind resistance as well as resistance from still water, waves, wave-making, and other factors to achieve normal navigation.

[0103] Based on the general surface ship standalone model proposed by the Japan Marine Modeling Group (MMG), a three-degree-of-freedom mathematical model of sail-assisted ship motion can be constructed to calculate the forces and power of sail-assisted ships. According to the MMG model, the motion of the ship is described using a right-handed Cartesian Earth coordinate system and a ship-based coordinate system. By combining the influence from the sail, it generates kinematic and dynamic differential equations, such as equations (4) and (5).

[0104]

[0105]

[0106] Where x0 and y0 are the horizontal coordinates in the Earth coordinate system, δ is the ship's rudder angle, ψ is the ship's heading angle, u, v, and r represent the translational and rotational velocities of the three degrees of freedom in the ship's coordinate system, and m is the ship's mass. x m y These represent the additional mass of the sail-assisted vessel in the Gx and Gy axes, respectively. zz and J zz These represent the moment of inertia and additional moment of inertia corresponding to the Gz axis in the ship's coordinate system. The effects on various parts of the ship, such as X, are discussed here. H This represents the force applied to the hull, specifically for u and X. P X represents a propeller. R Indicates rudder, X W Indicates environmental interference, X S This indicates a wing sail. Similarly, Y i i = HRSW, representing the force dedicated to v, in N. i The steering torque r is represented by the ship's mass; X and Y represent the ship's position at G. x and G y Forces in a direction, N represents the torque acting on the ship; subscripts H, P, R, and C represent the forces and torques exerted by the hull, propeller, rudder, and wind on the ship's structures above the waterline, respectively.

[0107] The propulsive force of the propeller can be expressed by formula (6).

[0108] X P =(1-t)ρn 2 D 4 K T (6)

[0109] Where ρ is the density of seawater, t is the propeller thrust deduction factor; n is the propeller speed, D is the propeller diameter, and K... T The propeller thrust coefficient can be expressed as a function of the advance coefficient J.

[0110] J=u(1-ω) / nD (7)

[0111] Where ω is the wake fraction.

[0112] The hydrodynamic and torque model acting on the rudder is as follows

[0113]

[0114] Among them, F N δ is the normal force of the rudder blade, t is the rudder angle, and t is the rudder blade R α is the deduction factor for rudder blade drag. H x is the correction factor for steering-induced lateral force. H x represents the distance from the point of application of the induced lateral force on the hull due to steering to the ship's center of gravity. R This indicates that the point of application of the lateral force on the rudder blade is at G. X The coordinate on the axis is -0.5L.

[0115]

[0116] A R For the rudder blade area, U R v is the effective incoming flow velocity at the rudder blade. R Let uR be the effective lateral velocity flowing into the rudder, and α be the effective longitudinal velocity flowing into the rudder. R Let f be the effective angle of attack relative to the rudder inflow, and let f be the slope corresponding to the lift coefficient when the angle of attack is 0. a .

[0117] The force exerted by the sail can be expressed by the following formula.

[0118]

[0119] In the formula, ρ a C is the density of air. X C is the thrust coefficient. Y S is the lateral thrust coefficient. w It is the projected area of ​​the sail, V a It is the relative wind speed that combines ambient wind and ship motion, x s It is the longitudinal distance from the point of application of the sail's side thrust to the ship's center of gravity.

[0120] The propulsive force of a sail is the result of the combination of lift and drag. For example... Figure 6As shown, when the ship's course line passes through the origin and intersects with C along the course line... L and C D When the curve is tangent to the curve, then the point of tangency is A(C). LA C DA The corresponding angle of attack is the optimal angle of attack under that wind direction, and therefore the corresponding thrust coefficient is the largest. The relationship between the sail thrust coefficient, lateral thrust coefficient, and sail lift coefficient and drag coefficient can be expressed by formula (11).

[0121] C X =C L sinβ-C D cosβ (11)

[0122] C Y =C L cosβ+C D sinβ

[0123] Where β is the relative wind direction angle. Furthermore, the relationship between the sail angle of attack α, the relative wind direction angle β, and the sail slewing angle (set sail rotation angle) φ is as follows: Once the relative wind angle is determined, the sail angle is controlled to operate at the optimal angle of attack in order to achieve the best boost effect.

[0124] Step 3: Calculate the wind field data along the target route and the relative wind direction and relative wind speed of the ship based on the ship's speed and course, and calculate the wind field probability distribution matrix and sail load probability matrix; and evaluate its energy-saving effect.

[0125] The relative wind field calculation method decomposes the extracted wind field data along the route, as well as the wind speed and direction caused by ship motion, in the u and v directions to calculate the relative wind field. Then, through ship force analysis and ship motion coordinate transformation, a ship motion model is established to calculate the ship's main engine power and effective power. After determining the relative wind direction and speed information along the route, the wind field probability matrix along the route is statistically obtained, as shown in Table 1.

[0126] Table 1 Wind Field Probability Matrix

[0127]

[0128] In the table, each row represents a wind speed range, such as: <1 represents [0, 1), <2 represents [1, 2), ... <25 represents [24, 25), ≥25 represents [25, ∞). Each column represents a wind direction range, such as: 0 represents [0, 5), 5 represents [5, 10), ... 355 represents [355, 360). Each data point in the table represents the wind field probability within that wind speed and direction range, such as: W 3,2This represents the probability value of wind speed being in the range of [2-3) m / s and wind direction being in the range of 5°-10°. The sum of all data in the matrix is ​​1.

[0129] Based on the wind field probability matrix along the route and the sail thrust calculation formula, the sail thrust load matrix along the route is calculated according to the following principles: Wind speed is taken as the upper limit of each interval, and wind direction is taken as the middle value of each interval. The resulting sail thrust load matrix along the route is shown in Table 2.

[0130] Table 2 Sail Thrust Load Matrix

[0131]

[0132] In the table, the data within the matrix represents the thrust generated by the sail within the corresponding wind speed and direction range, such as: F 3,2 This represents the thrust generated by the sail when the relative wind speed is 3 m / s and the relative wind direction is 7.5°. Summing the data in the sail thrust load matrix in Table 2 yields the total thrust FM that the sail can provide along the course, which can then be combined with the ship's reference speed V. S The auxiliary power provided by the sail on the route is calculated.

[0133] Step 4: Establish an energy-saving evaluation and assessment system for sail-assisted vessels and interpret and calculate its weights; After the energy-saving assessment, begin to establish an energy-saving index system for sail-assisted vessels. Constructing this system is the foundation for evaluating the energy-saving efforts of each sailing vessel. By formulating reasonable influencing indicators, such as the aerodynamic characteristics of the installed sails, vessel type, and route distribution, an energy-saving effect evaluation mechanism is established. This allows for the calculation of the energy-saving effect of the sail-assisted vessel on its own route, track zone, or within the global shipping range. The final calculation results can then quantitatively analyze the energy-saving effect of the vessel after installing sails, and thus serve as a reference for whether the vessel needs to install a sail-assisted navigation system.

[0134] The indicator system consists of five categories, such as Figure 7 As shown, these are airfoil sails, ship types, wind field information, route distribution, and cargo trade volume, from which a three-level indicator is established as follows: Figure 8 As shown.

[0135] (1) Types of sails

[0136] Based on the comprehensive assessment above, airfoil sails are one of the most widely used sails globally. They are simple in structure, easy to control, low in cost, and offer relatively ideal overall energy-saving performance.

[0137] (2) Types of ships

[0138] The ship type index is divided according to the three types of ships suitable for installing sail-assisted navigation equipment: bulk carriers, oil tankers, and LNG carriers, which facilitates subsequent classification, calculation and comparison of the energy-saving effects of various ships.

[0139] (3) Wind field information

[0140] Under the premise of wind resource analysis, the acquisition and processing of wind field information are fundamental to the analysis of wind resources.

[0141] (4) Route distribution

[0142] Trade routes span the globe, and the number and distance of these routes can vary significantly across different sea areas and track zones. Wind resources are globally distributed, and ocean wind resource data remains relatively constant or changes only slightly over a large area. Dividing global trade routes by sea area and track zone reveals that wind resources are generally consistent within the same or similar sea areas and track zones, while wind resources can differ considerably between routes in distant sea areas and track zones. This allows for comparisons of the energy-saving effects of sails on ships operating within the same sea area or track zone, as well as energy-saving comparisons between different ships within a specific sea area. Furthermore, it enables the calculation of the overall energy-saving effect of sails on a single ship and on a given route globally, providing multi-faceted and comparative energy-saving results.

[0143] (5) Volume of goods trade

[0144] When a ship is in operation, the cargo load is not constant from the port of origin to the port of destination. Loading and unloading operations typically occur at intermediate ports, causing changes in the actual cargo volume and thus affecting the ship's actual tonnage, ultimately impacting the energy-saving effect of sail-assisted navigation. Therefore, it is necessary to further classify the ship's cargo volume to eliminate this influencing factor and improve the accuracy of the final energy-saving calculation.

[0145] Once the evaluation system is constructed, the weights of each component should be allocated according to the established principles. The weight P should be assigned based on the actual situation of the target sail-assisted vessel, including vessel type, tonnage, cargo volume, navigation area, proportion of sea areas and routes, wind field data of the sea area where the route is located, voyage distance, and aerodynamic characteristics of the sails. All of the above data should be comprehensively considered, and the weights should be objectively allocated.

[0146] For ships actually sailing, given the number of sails, ship type, cargo capacity, and specific route, the total weight of the ship is equal to the sum of the weights of each indicator.

[0147] When considering ship types, weights are usually defined by the number of ships or the type of ship. However, in recent years, the number of ship types has been increasing, and the number of ships in actual use has been rising, making the ship type calculation complex and cumbersome. Therefore, a comprehensive weighting is calculated using the number of ships of different tonnages. When calculating the proportion of the sail energy-saving effect of the target ship type to the total energy-saving effect of all ships globally, the weight is defined by the number of ships.

[0148] The ship type is the ratio of the total number of oil tankers, bulk carriers and LNG carriers suitable for installation to the total number of all ships in the world, and its proportion is: A1. Its effect is the ratio of the number of bulk carriers, oil tankers and LNG carriers to the total number of all trade ships in the world.

[0149] The proportion of sail-assisted navigation effect on bulk carriers among all types of ships suitable for sail installation is:

[0150] A2 = F12 / (F11 + F12 + F13);

[0151] That is, the ratio of the number of bulk carriers to the sum of the number of bulk carriers, oil tankers, and LNG carriers.

[0152] The proportion of the sail-assisted navigation effect of oil tankers to the overall effect of sail installation on all types of ships suitable for sail installation is:

[0153] A3 = F11 / (F11+F12+F13);

[0154] That is, the ratio of the number of oil tankers to the sum of the number of bulk carriers, oil tankers, and LNG carriers.

[0155] The proportion of the sail-assisted navigation effect of LNG carriers to the overall effect of sail installation on all types of ships suitable for sail installation is:

[0156] A4 = F13 / (F11 + F12 + F13).

[0157] That is, the ratio of the number of LNG carriers to the sum of the number of bulk carriers, oil tankers, and LNG carriers.

[0158] And F11 / (F11+F12+F13)+F12 / (F11+F12+F13)+F13 / (F11+F12+F13)=1.

[0159] That is, A2 + A3 + A4 = 1.

[0160] When ship classification becomes more detailed, such as calculating the proportion of sail-assisted navigation effect of large ore carriers to that of bulk carriers:

[0161] A5=F128 / (F121+F122+F123+F124+F125+F126+F127+F128+F129);

[0162] That is, the ratio of the number of large ore carriers to the total number of bulk carriers.

[0163] This leads to the conclusion that the sail-assisted navigation effect accounts for a significant proportion of the overall effect of different bulk carrier types.

[0164] In summary: when the basic information of the ship is known, the weight of the ship type index is B2 = A1 * A2 * A5, where A1 is the number of bulk carriers, oil tankers, and LNG carriers and the ratio to the total number of all trade ships in the world; A2 is the proportion of the sail-assisted navigation effect of bulk carriers to the overall effect of all types of ships suitable for sail installation; and A5 is the proportion of the sail-assisted navigation effect of the target specific ship type to the overall navigation effect of that ship type category.

[0165] The same principle applies to oil tankers and LNG carriers. Finally, by determining the weights of each indicator in the evaluation system and knowing the energy-saving effect of sail-assisted navigation, the energy-saving effect η of the sail on the route can be calculated.

[0166] Step 5: Calculate the overall energy-saving effect of the ship.

[0167] Define a target sail-assisted vessel, and based on its operating route, the proportion of total sail energy saving effect Н globally is equal to the product of the sail energy saving effect η of the operating route of that sail-assisted vessel and its weight.

[0168] This indicator can not only quantitatively describe the energy-saving effect of the sails on the target sail-assisted navigation vessel on its operating route, but also quantitatively describe the proportion of the sail energy-saving effect among vessels suitable for installing sail-assisted navigation equipment in all global sea areas and all global routes. It can even change the classification benchmark of the indicator. This allows for a reasonable evaluation of the comprehensive performance of the sail-assisted navigation system, a comparison of the economy, practicality, and effectiveness of the sail effect of vessels equipped with sail-assisted navigation equipment, and a verification of the feasibility of installing sails on vessels that have not yet been equipped with sail-assisted navigation equipment.

[0169] Overall beneficial effects:

[0170] This invention can not only quantitatively describe the energy-saving effect of sails on the target sail-assisted navigation vessels on their operating routes, but also quantitatively describe the proportion of energy-saving effect of sails among vessels suitable for installing sail-assisted navigation equipment in global sea areas and on all global routes. It can even change the classification criteria of the indicators to evaluate the economic efficiency, practicality, and effectiveness of the sail effects of vessels equipped with sail-assisted navigation equipment, and also verify the feasibility of installing sails on vessels that have not yet been equipped with sail-assisted navigation equipment.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing an energy-saving evaluation index system for sail-assisted navigation, characterized in that, include, Step 1: Determine the type of sail to be assessed for energy efficiency and the type of vessel that can be fitted with sails. Obtain global trade route information, wind farm data, and vessel information. The global trade route information includes vessel type, vessel model, port of origin, intermediate ports, port of destination, cargo volume, and trade volume. Step 2: Determine the sail type as a wing sail. Taking the sail-assisted vessel as the object, establish a motion model of the sail-assisted vessel through force analysis and coordinate transformation. This motion model is used to calculate the main engine power of the sail-assisted vessel, and based on the main engine power, calculate the effective power of the sail-assisted vessel. The navigation area is determined based on the route information of the sail-assisted vessel, and the spatiotemporal distribution characteristics of wind speed and direction are obtained based on the wind field data corresponding to the navigation area. Based on the spatiotemporal distribution characteristics of wind speed and direction, a wind resource probability matrix is ​​constructed for the route of sail-assisted vessels. The propulsion power that the sails can provide within the route is then calculated based on the wind resource probability matrix. The propulsion power provided by the sail is calculated according to formula (2). (2) in, V S For reference speed of the ship, F i.j The total thrust of the ship's sails. i , j The index value of the thrust load matrix. i =1,2, … 26, j =1, 2, … 72; The energy-saving effect of sails on sail-assisted navigation vessels within a course is calculated based on the ship's effective power and the propulsion power that sails can provide. Step 3: Establish an energy-saving index system for sail-assisted navigation vessels, and determine the weight of each index in the energy-saving index system for sail-assisted navigation vessels. The energy-saving index system for sail-assisted navigation vessels includes vessel type, vessel tonnage, cargo volume, navigation area, proportion of sea area routes, wind field data of the sea area where the route is located, voyage distance, and aerodynamic characteristics of the sails. The weighting value under the ship type index is B2=A1 A2 A5, where A1 is the number of bulk carriers, oil tankers, and LNG carriers and the ratio to the total number of all trade vessels globally; A2 is the proportion of sail-assisted navigation effect for bulk carriers relative to the overall effect of sail-assisted navigation for all types of vessels suitable for sail installation; and A5 is the proportion of sail-assisted navigation effect for a specific target ship type relative to the overall navigation effect for that ship type category. Step 4: Determine the target vessel. Calculate the sum of the weights of the corresponding indicators for the target vessel according to the energy-saving index system for sail-assisted navigation and express it as the total weight. Calculate the energy-saving effect of installing sails on the target vessel within its own route, track zone, or global shipping range. Determine whether the target vessel needs to install sails based on the energy-saving effect and the total weight. The determination of whether a target ship needs to install sails based on energy-saving effect and total weight is as follows: the proportion of total sail energy-saving effect of the target ship is calculated according to formula (3). If the proportion meets the threshold, it means that the target ship is suitable for installing sails; otherwise, it means that the target ship is not suitable for installing sails. H=h w P (3) Where P is the total weight, η w For energy saving effect, H represents the proportion of total sail energy saving effect.

2. The method for constructing an energy-saving evaluation index system for sail-assisted navigation according to claim 1, characterized in that, The energy-saving effect of the sail on a sail-assisted ship within the course is calculated based on the ship's effective power and the propulsion power provided by the sail. The energy-saving effect is calculated according to formula (1). η w , (1) in, P H The effective power of a ship during navigation. P W The propulsion power that a sail can provide.

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