A method and system for evaluating the application effect of a ship underwater surface energy-saving technology

Abstract

The application discloses a kind of ship underwater surface energy-saving technology practical ship application effect evaluation method and system, the method includes: collecting the original operation data of target ship in reference period and evaluation period;Build three-level evaluation working condition system;Original operation data is standardized and cleaned, sample size determination and format uniformity, exclude abnormal working condition data, and according to three-level evaluation working condition system, data is matched to corresponding sub-working condition, and annual theoretical operation index is counted;According to the operation index of reference period and evaluation period under corresponding sub-working condition, calculate the oil saving rate under annual comprehensive operation working condition and different speed interval, to evaluate the practical ship application effect of the application underwater surface energy-saving technology;The application effectively excludes the influence of environment and operation factor on energy consumption, improves the accuracy and scientificity of underwater surface energy-saving technology practical ship application effect evaluation.

Description

Technical Field

[0001] This invention relates to a method and system for evaluating the effectiveness of practical ship applications, specifically to a method and system for evaluating the effectiveness of practical ship applications of underwater surface energy-saving technology. Background Technology

[0002] In recent years, with the continuous introduction and tightening of shipping emission reduction policies, the industry has gradually increased its attention to the research and application of various energy-saving technologies. Among them, underwater surface energy-saving technologies, such as anti-fouling coating technology, propeller polishing technology, hull surface cleaning technology, and propeller coating technology, have become key technologies for research and application in the field of ship energy conservation. How to quantitatively evaluate the energy-saving effect of these technologies in actual ship applications has become a concern in the industry. Currently, numerical simulation technology and model testing technology have been used to evaluate energy-saving effects. However, the meteorological and sea conditions and loading conditions of actual ship operations are quite complex, making it difficult for these technologies to truly reflect the energy-saving effects in actual ship operations and unable to provide a reliable quantitative basis for the large-scale promotion of energy-saving technologies.

[0003] Anti-fouling coating technology refers to the formation of a protective coating on the underwater surface of a ship's hull through processes such as spraying and coating. Its core function is to reduce drag and inhibit the accumulation of marine organisms, thereby reducing ship energy consumption and extending maintenance cycles. It is a crucial technology for improving ship energy efficiency and economy. Current coating types include superhydrophobic, superhydrophilic, low surface energy, or self-polishing functional coatings. Propeller polishing technology refers to the smoothing and finishing of propeller blades through processes such as grinding, polishing, and fine polishing. Its core function is to reduce surface roughness, improve surface smoothness, and reduce cavitation corrosion, thereby improving propeller propulsion efficiency and reducing navigation energy consumption. It is a crucial technology for improving propeller hydrodynamic performance. Hull surface cleaning technology refers to the removal of biofouling from the underwater surface of the ship's hull using methods such as high-pressure water jets, cavitation jets, mechanical rotating brushes, and underwater robots. Its core function is to reduce navigation friction, protect anti-fouling coatings, and reduce energy consumption and maintenance costs. It is a crucial technology for improving ship energy efficiency and operational economy. Propeller coating technology refers to the process of forming a uniform and dense functional film on the surface of propeller blades through spraying, coating and other processes. It can be used to resist cavitation corrosion, reduce surface roughness, inhibit the attachment of marine organisms, reduce operating noise, thereby improving propeller propulsion efficiency and realizing energy conservation in ships. It is an important technology for improving the energy efficiency level of ships.

[0004] The aforementioned underwater surface energy-saving technologies have been applied to mainstream ships such as bulk carriers and container ships. However, existing energy-saving effect assessments mostly rely on numerical simulation or experimental verification, which differ significantly from the actual navigation conditions of real ships. The assessment results are not convincing enough and cannot meet the industry's standardized and refined assessment needs, thus limiting the promotion and application of related technologies. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method and system for evaluating the practical application effect of underwater surface energy-saving technologies on ships. This method can standardize, accurately and scientifically evaluate the practical energy-saving effect of various underwater surface energy-saving technologies on ships, providing a basis for large-scale promotion and application.

[0006] The evaluation method described in this invention includes: Collect raw operational data of the target vessel during the reference period and the evaluation period, which are the operational phases before and after the application of underwater surface energy-saving technology, respectively; A three-level assessment condition system is established, comprising Level 1 period condition, Level 2 loading condition, and Level 3 speed range condition. The Level 1 period condition is divided according to the reference period and the assessment period, the Level 2 loading condition is divided according to the ship's loading status, and the Level 3 speed range condition is divided according to the ship type. The original operational data is standardized and cleaned, sample size is determined and format is unified, abnormal operating condition data is removed, and the cleaned data is matched to the corresponding sub-operating condition according to the three-level evaluation operating condition system. Based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges is calculated to evaluate the actual ship application effect of the underwater surface energy saving technology.

[0007] Preferably, the steps for calculating the annual theoretical operating indicators include: Calculate the percentage of operating days for the target vessel during the reference and assessment periods based on the original operating data; calculate the average percentage of operating days for the target vessel under light / heavy load conditions during the reference and assessment periods based on the original operating data; calculate the annual theoretical effective sailing days based on the average percentage of operating days under light / heavy load conditions. Based on the cleaned operational data, calculate the percentage of operating days for the target vessel in each speed range under light / heavy load conditions during the reference and evaluation periods; calculate the average speed, average main engine speed, and average daily fuel consumption of the target vessel in different speed ranges under light / heavy load conditions during the reference and evaluation periods; and calculate the daily fuel savings, average daily fuel consumption, and average daily fuel savings under light / heavy load conditions based on the average daily fuel consumption and the percentage of operating days in each speed range.

[0008] The evaluation system of the present invention includes: The data collection module is used to collect raw operational data of the target vessel during the reference period and the evaluation period, which are the operational stages before and after the application of underwater surface energy-saving technology, respectively. The working condition construction module is used to build a three-level evaluation working condition system, including the first-level period working condition, the second-level loading working condition, and the third-level speed range working condition. The first-level period working condition is divided according to the reference period and the evaluation period, the second-level loading working condition is divided according to the ship loading status, and the third-level speed range working condition is divided according to the ship type. The data processing module is used to standardize and clean the original operational data, determine the sample size and format, remove abnormal operating condition data, and match the cleaned data to the corresponding sub-operating condition according to the three-level evaluation operating condition system. The effect evaluation module is used to calculate the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, so as to evaluate the actual ship application effect of the underwater surface energy saving technology.

[0009] Compared with existing technologies, this invention has the following significant advantages: 1. By establishing a three-level evaluation system including period, loading, and speed, it enables the comparison of the energy-saving effects of underwater surface energy-saving technologies under the same or similar operating conditions, effectively eliminating interference from non-technical factors; 2. By setting the reference period and evaluation period to a one-year cycle, it can fully cover seasonal and meteorological / sea state changes, ensuring the representativeness of the evaluation results in long-term operation; 3. Through a standardized data cleaning process, abnormal operating condition data such as low visibility and shallow water are eliminated, ensuring the quality of data used for statistical analysis and making the calculation of fuel-saving rate more scientific and reasonable; 4. Based on the standardized calculation and statistical analysis of the operating probability and fuel-saving amount in each speed range during actual ship operation, it achieves standardized, accurate, and scientific evaluation of the actual ship energy-saving effects of various types of ships and various underwater surface energy-saving technologies. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the evaluation method for the practical application effect of the underwater surface energy-saving technology of ships provided by the present invention.

[0011] Figure 2 This is a schematic diagram of the three-level evaluation condition system provided by the present invention. Detailed Implementation

[0012] Example 1

[0013] refer to Figure 1 This embodiment provides a method for evaluating the practical application effect of underwater surface energy-saving technology on ships. The underwater surface energy-saving technology selected is propeller coating technology, and specifically includes the following steps:

[0014] S1. Collect the original operational data of the target vessel during the reference period and the evaluation period. The reference period is the operational phase before the application of underwater surface energy-saving technology, and the evaluation period is the operational phase after the application of underwater surface energy-saving technology.

[0015] In this step, raw operational data of the vessel can be obtained through various channels and interfaces. For example, high-frequency sensor data can be automatically collected through the ship's integrated automation system or the ship's navigation data recorder. Referring to Table 1 below, operational data includes voyage date, speed, main engine speed, no-load or light-load status, heavy-load status, daily fuel consumption, daily mileage, daily voyage time, slip rate, weather and sea conditions (wind force, wave magnitude, current speed), vessel operation status (loading, unloading, waiting in port, drifting, normal navigation, etc.), navigation water conditions, and abnormal operating conditions (navigation in low visibility, shallow water, narrow channel). In addition, data can also be collected through the nautical log, engine log, bill of lading, manifest, midday report, etc. The data collection frequency is daily, and the collection period must cover the entire reference period and evaluation period.

[0016] To cover the complete seasonal cycle and changes in weather and sea conditions, both the reference period and the evaluation period are set at one year from the end of the ship's dry-docking. This is because ships typically undergo thorough hull cleaning, rust removal, and repainting during dry-docking, at which point the hull surface roughness is at its optimal level. Over time, marine biofouling and paint degradation gradually occur on the hull surface, leading to a gradual increase in drag. Therefore, choosing one year from the end of dry-docking as the reference period (before the application of underwater surface energy-saving technology) and the evaluation period (after the application of underwater surface energy-saving technology) ensures the comparability of the hull fouling evolution process between the two periods. Furthermore, the one-year cycle fully encompasses the four seasons—spring, summer, autumn, and winter—including operational conditions under different water temperatures and wind and wave conditions. By collecting real-ship data throughout the entire seasonal cycle, the accuracy, objectivity, and credibility of the evaluation results can be maximized, ensuring that the energy-saving effect assessment reflects the true level of the technology in actual operation.

[0017] Table 1. Raw operational data generated during actual ship operation Basic Information Sailing date y / m / d Year / Month / Day sailing speed Kn Festival Main unit speed r / min revolutions per minute Ship status Light load condition B Light load Overload status L Heavy load Weather and Sea Conditions wind Bft Beaufort scale wave level SS Wave level Flow rate Kn Festival Navigation status Daily fuel consumption t / d tons / day Daily sailing distance nm / d Sea mile / day Daily sailing time h / d Hours / day Water conditions Navigation waters W / R / C Ocean / Nearshore / Inland Waterway Loading status Loading status B / L Light load / Heavy load Abnormal operating conditions Low visibility Y / N whether shallow water navigation Y / N whether Navigation in narrow waterways Y / N whether

[0018] S2. Establish a three-level assessment condition system including Level 1 period condition, Level 2 loading condition, and Level 3 speed range condition. The Level 1 period condition is divided according to the reference period and the assessment period, the Level 2 loading condition is divided according to the ship's loading status, and the Level 3 speed range condition is divided according to the ship type.

[0019] Specifically, see Figure 2The first-level operating conditions are divided into a reference period (R) and an evaluation period (A) based on the construction milestones of the propeller coating technology. The reference period (R) represents the state of the target vessel before the propeller coating technology construction, which is one year of the vessel's operating time from the end of dry dock repair. Multiple reference periods can be labeled as R1, R2...Rn. The evaluation period (A) represents the state of the target vessel after the propeller coating technology construction. Multiple evaluation periods can be labeled as A1 (0-365 days), A2 (365-730 days)...An, and are used to analyze the durability of the energy-saving effect of the coating technology.

[0020] The secondary loading condition can be classified according to the ship's average draft. In some embodiments, a draft threshold can be preset. D threshold When the ship's average draft D mean (The average of the forward draft and the aft draft, or the draft corrected for the midships draft) is greater than or equal to D threshold When the average draft is... D mean Less than D threshold When the condition is determined to be either unloaded or lightly loaded (condition B), it is marked as: RB (lightly loaded condition during the reference period), A1-B (lightly loaded condition during the evaluation period 1), or Rn-B (lightly loaded condition during the reference period n).

[0021] Draft threshold D threshold This can be determined based on the ship's loading manual. For bulk carriers and large oil tankers, due to their typically unidirectional loading (heavy load) and unidirectional empty or lightly loaded return (ballast), their draft distribution exhibits a distinct bimodal characteristic. Therefore, the draft threshold can be used to determine the draft. D threshold The loading conditions can be clearly and accurately divided into heavy load, empty load, or light load. For container ships, since they usually load and unload containers continuously between multiple ports, the draft changes are relatively continuous. At this time, according to the operating characteristics of container ships, the draft range can be divided into several more detailed intervals, or the two representative intervals of heavy load and empty (light load) can still be used, and the data of the intermediate transitional state can be eliminated or classified into the closer category.

[0022] The division of the three-level speed range operating conditions requires differentiating the speed ranges based on the ship type (e.g., bulk carriers, oil tankers, liquefied gas carriers, container ships, roll-on / roll-off ships, etc.), and breaking the data down into sub-operating conditions for each speed range. According to the embodiments provided in this application, different ship types have different daily operating speeds, which can be divided into 0.5 knots, 1 knot, or 2 knots according to the actual operating characteristics of the ship type. For example, for very large bulk carriers with a maximum design speed of around 15 knots, their commonly used operating speed is usually between 11 and 14 knots. In this case, 1 knot can be used as an interval to divide the speed into intervals such as: ..., [10, 11), [11, 12), [12, 13), [13, 14), [14, 15), etc. For large container ships with a maximum design speed of around 24 knots, their operating speed varies greatly due to route planning and on-time performance, and may fluctuate widely between 15 and 22 knots. In this case, 2 knots can be used as an interval to divide the speed into intervals such as: ..., [14, 16), [16, 18), [18, 20), [20, 22), etc.

[0023] After defining the speed ranges, add speed range numbers after the secondary operating conditions label, for example: R1-L1 (the first speed range under heavy load conditions in reference period 1), A1-B2 (the second speed range under light load conditions in evaluation period 1). If a speed range with an operating percentage of less than one percent is found, it indicates that the vessel rarely sails at that speed, the data sample size in this range is too small, and the statistically obtained average fuel consumption and speed are easily affected by accidental factors (such as brief periods of tailwind and tailwind or headwind and headwind), lacking representativeness. Therefore, speed ranges with an operating percentage of less than one percent are merged into adjacent speed ranges. For example, if the operating share of the [9, 10) interval is 0.6%, while the operating share of the adjacent [10, 11) interval is 15%, then all the data from the [9, 10) interval can be merged into the [10, 11) interval, resulting in the [9, 11) interval. Alternatively, the data from the [9, 10) interval can be directly incorporated into the [10, 11) interval for unified statistics. This merging process effectively improves the stability and accuracy of subsequent data analysis.

[0024] Statistics are compiled separately for reference period / evaluation period and heavy load / light load, and a unified operating condition statistical table is formulated, as shown in Table 2 below. The core statistical indicators are number of operating days, operating percentage, average speed, average main engine speed, average daily fuel consumption, and average daily mileage.

[0025] Table 2 Operating Condition Statistics Table Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance R2-L parameter R2-L1 R2-L2 R2-L3 R2-L4 R2-L5 R2-L6 R2-L7 R2-L8 total Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance RL (average) parameter R-L1 R-L2 R-L3 R-L4 R-L5 R-L6 R-L7 R-L8 total Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance RB R1-B parameter R1-B1 R1-B2 R1-B3 R1-B4 R1-B5 R1-B6 R1-B7 R1-B8 total Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance R2-B parameter R2-B1 R2-B2 R2-B3 R2-B4 R2-B5 R2-B6 R2-B7 R2-B8 total Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance RB (average) parameter R-B1 R-B2 R-B3 R-B4 R-B5 R-B6 R-B7 R-B8 total Less than 8 sections Sections 8-9 Sections 9-10 Sections 10-11 Sections 11-12 Sections 12-13 Sections 13-14 14 or more Operating days Operating percentage average speed Average host speed Average daily fuel consumption Average daily flight distance

[0026] S3. Standardize and clean the raw operational data, determine the sample size and format, remove abnormal operating condition data, and match the cleaned data to the corresponding sub-operating conditions according to the three-level evaluation operating condition system. This step ensures the validity and reliability of the data.

[0027] To eliminate interference factors other than propeller coating technology and ensure the comparability of data between the reference period and the evaluation period, a condition matching verification was carried out after the establishment of the three-level evaluation condition system. The verification factors were: (1) ship basic condition, i.e., similarity of hull fouling degree, main engine / propeller coating technology condition, etc.; (2) operating environment, i.e., similarity of operating environment such as route distribution, meteorological and sea conditions (wind force, wave level, and current speed are judged according to relevant WMO and IMO standards), and navigation waters; (3) operating characteristics, i.e., similarity of operating characteristics such as loading conditions and daily sailing time distribution.

[0028] S301. Standardize and clean raw operational data to remove invalid and abnormal data. In some embodiments, the data to be removed includes: abnormal data with a slip rate greater than 35% or less than -20%; severe weather and sea state data under conditions of gale force 8 or greater (Beaufort scale), large waves of force 5 (significant wave height greater than or equal to 2.5m, WMO sea state classification), and strong current of 2 knots; abnormal operating condition data such as low visibility fog, haze, heavy rain (less than 1 nautical mile), shallow water effect (navigation depth less than 2 times the ship's draft), and navigation in narrow waterways; non-navigation status data such as ship loading, unloading, waiting in port, drifting, and rescue operations; abnormal equipment data such as main engine speed deviating from the average speed by ±10% and daily fuel consumption deviating from the average speed by ±15%; and non-continuous navigation data with actual daily navigation time of less than 20 hours.

[0029] S302. The sample size is based on the effective flight days. The sample size of each level 3 sub-condition must meet the following requirements: (1) a minimum sample size of not less than 5 effective flight days; (2) an ideal sample size of not less than 10 effective flight days; (3) sub-conditions that cannot meet the effective flight days requirement are directly excluded and do not participate in subsequent calculations.

[0030] S303. Standardize the format of the cleaned valid data. In some embodiments, standardize the parameter units and parameter precision. The parameter units include speed (Kn), main engine speed (r / min), daily fuel consumption (t / d), slip rate (%), and daily actual sailing time (h / d); all numerical parameters are retained to two decimal places.

[0031] After the above data processing steps, the retained data consists of steady-state navigation data of the vessel in deep sea, open water, good visibility, and normal operating conditions. These valid data are then precisely allocated to the corresponding sub-conditions based on their period (reference period / evaluation period), loading status (heavy load, empty load, or light load), and speed range.

[0032] S304. For each sub-operating condition, calculate its annual theoretical operating indicators. All parameters are differentiated by reference period / evaluation period and heavy load / light load conditions. For reference and evaluation periods with multiple periods of data, average calculation or individual calculation can be used.

[0033] To calculate the percentage of annual operating days, the target vessel's effective sailing days during the reference and assessment periods are calculated based on the original operating data. The specific formula is as follows:

[0034] No. g Percentage of operating days in each reference period m : ;

[0035] No. g Percentage of operating days in each assessment period n : ;

[0036] Average percentage of operating days k : ;

[0037] in, x y represents the sum of quantities in the reference period, and y represents the sum of quantities in the evaluation period.

[0038] S305. Calculate the operating percentage of the target vessel in lightly loaded / heavily loaded conditions during the reference period and the assessment period based on the original operating data, and the average percentage. The specific formula is as follows:

[0039] No. g Percentage of light-load operating days in each reference period Rd B : ;

[0040] No. g Percentage of heavy-load operating days in each reference period Rd L : ;

[0041] No. g Percentage of light-load operating days in each assessment period Ad B : ;

[0042] No. g Percentage of heavy-load operating days in each assessment period Ad L : ;

[0043] Average percentage of days operated under light load conditions : ;

[0044] Average percentage of days operating under heavy load conditions : .

[0045] in, Indicates the first i The percentage of light-load operating days in the reference period. Indicates the first i The percentage of days operated under light load conditions during the assessment period. Indicates the first i The percentage of heavy-load operating days in each reference period. Indicates the first i The percentage of days operating under heavy load conditions during the assessment period.

[0046] S306. Calculate the annual theoretical effective sailing days based on the average percentage (k) of operating days under light / heavy load conditions. The specific formula is as follows:

[0047] Theoretical number of days per year under light load conditions Theoretical number of days per year under heavy-load operating conditions .

[0048] S307. Calculate the operational percentage for each speed range under light / heavy load conditions based on the cleaned operational data. The specific formula is as follows:

[0049] No. g The percentage of operations in the i-th speed range under light load conditions during the reference period. : ;

[0050] No. g The percentage of operations in the i-th speed range under heavy-load conditions during the reference period : ;

[0051] No. g The percentage of operations in the i-th speed range under light load conditions during the assessment period : ;

[0052] No. g The percentage of operations in the i-th speed range under heavy-load conditions during the assessment period : ;

[0053] Operating percentage of the i-th speed range under light load conditions : ;

[0054] Operating percentage of the i-th speed range under heavy load conditions : .

[0055] S308. Calculate the average airspeed, average main engine speed, and average daily fuel consumption for each airspeed range. The average main engine speed is used to help verify the accuracy of the fuel consumption data. Specifically:

[0056] Average speed during the reference period: lightly loaded Heavy load , is the average value of the valid data within the i-th speed interval;

[0057] Average speed during the assessment period: light load Heavy load , which is the average value of the valid data within the i-th speed range.

[0058] Average host speed during reference period: light load Heavy load , is the average value of the valid data within the i-th speed interval;

[0059] Average host speed during the evaluation period: light load Heavy load , is the average value of the valid data within the i-th speed interval;

[0060] Daily fuel consumption for the i-th speed range during the reference period: ; ;

[0061] Daily fuel consumption in the i-th speed range during the evaluation period: ; ;

[0062] S309. Calculate fuel savings and average daily fuel consumption for different speed ranges. Based on average daily fuel consumption and the operating percentage of each speed range, calculate daily fuel savings, average daily fuel consumption, and average daily fuel savings for each operating condition. Daily fuel savings are the basic indicator of energy-saving performance, average daily fuel consumption is the basis for calculating annual fuel consumption, and average daily fuel savings are used to analyze energy-saving differences under different operating conditions. The specific formula is as follows:

[0063] No. i The daily fuel saving for a given speed range is the difference between the average daily fuel consumption during the reference period and the evaluation period within the same speed range. A positive value indicates a fuel saving. The formula is:

[0064] Light load conditions: ;

[0065] Heavy-duty operating conditions: ;

[0066] The daily average fuel consumption is the weighted sum of the daily average fuel consumption for each speed range and the corresponding operational percentage, calculated using the following formula:

[0067] Reference period:

[0068] Light load conditions: ;

[0069] Heavy-duty operating conditions: .

[0070] The average daily fuel savings, calculated as the weighted sum of daily fuel savings for each speed range and the corresponding operational percentage, is given by the following formula:

[0071] Evaluation period:

[0072] Light load conditions: ;

[0073] Heavy-duty operating conditions: .

[0074] S4. Based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, calculate the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges, so as to evaluate the actual ship application effect of underwater surface energy saving technology.

[0075] S401. Analyze the differences in the energy-saving effect of propeller coating technology at different speeds, identify the optimal speed range for which the technology is best suited, and calculate the fuel-saving efficiency for each speed range. The formula is as follows:

[0076] Light load conditions: ;

[0077] Heavy-duty operating conditions: .

[0078] in, This indicates the fuel saving rate at different speed ranges under light load conditions. This indicates the average daily fuel savings under light load conditions at different speed ranges during the evaluation period. This indicates the average daily fuel consumption at different speed ranges under light load conditions during the reference period. This indicates the fuel saving rate at different speed ranges under heavy load conditions. This indicates the average daily fuel savings under heavy load conditions at different speed ranges during the evaluation period. This indicates the average daily fuel consumption at different speed ranges under heavy load conditions during the reference period.

[0079] S402. Considering the actual characteristics of alternating light and heavy load operations of ships, calculate the fuel saving rate under the annual comprehensive operating conditions. The specific steps are as follows: Calculate the theoretical fuel consumption under the annual comprehensive operating conditions. Specifically, it is necessary to calculate the annual comprehensive theoretical fuel consumption for both light and heavy load conditions during the reference period. The formula is:

[0080] Reference period annual comprehensive theoretical fuel consumption y Rc :

[0081] The theoretical fuel savings under annual comprehensive operating conditions are calculated, with the positive value representing the actual total fuel savings. The formula is as follows: y s : ;

[0082] The fuel-saving rate under comprehensive annual operating conditions is calculated as the ratio of the annual comprehensive theoretical fuel savings to the annual comprehensive theoretical fuel consumption during the reference period. It reflects the fuel-saving ratio of the coating technology relative to the baseline state. The formula is: ;

[0083] in, y r This indicates the fuel saving rate under comprehensive annual operating conditions. y s This represents the theoretical fuel savings under comprehensive annual operating conditions, while the positive value represents the actual total fuel savings. y Rc This represents the annual comprehensive theoretical fuel consumption for the reference period; g B This indicates the theoretical number of days per year under light load conditions. g L This indicates the theoretical number of days per year under heavy load conditions. AsA B This indicates the average daily fuel consumption under light load conditions during the reference period. AsA L This indicates the average daily fuel consumption under heavy load conditions during the reference period. RcA B This indicates the average daily fuel consumption under light load conditions during the reference period. RcA LThis indicates the average daily fuel consumption under heavy load conditions during the reference period.

[0084] S5. To enhance the scientific validity and persuasiveness of the evaluation results, the fuel-saving rate results were cross-validated and the uncertainty was analyzed. The correlation between speed, engine speed, and fuel consumption was verified. If, at the same speed, the engine speed decreased and the slip rate fluctuated reasonably after the installation of underwater surface energy-saving technology, and the trend was consistent with the reduction in fuel consumption, then the energy-saving effect data was deemed reliable.

[0085] S6. After the evaluation is completed, output a standardized on-ship energy-saving effect evaluation report of propeller coating technology. The report shall include at least the following contents: basic information of the evaluated ship (ship type, tonnage, type of underwater surface energy-saving technology, dock repair information, etc.), data collection and cleaning process (collection channels, cycle, cleaning standards, sample size), statistical results of evaluation conditions (number of operating days, operating percentage, core basic parameters for each condition), calculation table of core parameters (theoretical number of days, average daily fuel consumption, daily fuel savings, etc.), fuel saving rate conclusion (annual comprehensive fuel saving rate, fuel saving efficiency in each speed range, fuel saving effect in each loading condition), verification and analysis results, and evaluation conclusion (determination of energy saving effect).

[0086] Example 2

[0087] This embodiment provides an evaluation system for the practical application effect of underwater surface energy-saving technology on ships, including:

[0088] The data collection module is used to collect raw operational data of the target vessel during the reference period and the evaluation period. The reference period is the operational phase before the application of underwater surface energy-saving technology, and the evaluation period is the operational phase after the application of underwater surface energy-saving technology.

[0089] The working condition setup module is used to build a three-level assessment working condition system. The three-level assessment working condition system includes a first-level period working condition, a second-level loading working condition, and a third-level speed range working condition. The first-level period working condition is divided according to the reference period and the assessment period, the second-level loading working condition is divided according to the ship's loading status, and the third-level speed range working condition is divided according to the ship type.

[0090] The data processing module is used to standardize and clean the original operational data, determine the sample size and format, remove abnormal operating condition data, and match the cleaned data to the corresponding sub-operating condition according to the three-level evaluation operating condition system.

[0091] The effect evaluation module is used to calculate the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, so as to evaluate the actual ship application effect of the underwater surface energy saving technology.

[0092] In some embodiments, the effectiveness evaluation module can also provide a prediction of the energy-saving effect decay rate when outputting the evaluation report. Since the effectiveness of any underwater surface energy-saving technology gradually diminishes over time due to coating aging and the adhesion of marine microorganisms, the effectiveness evaluation module analyzes the fuel-saving rate trends for the first 3 months, 6 months, 9 months, and the full year of the evaluation period to fit a mathematical curve showing the fuel-saving rate decay over time. Based on this curve, the system can predict the expected fuel-saving effect of the technology in the second and third years and automatically calculate the optimal hull cleaning or repolishing cycle. This forward-looking predictive function helps ship owners develop more scientific and cost-effective ship maintenance plans, avoiding over-maintenance or under-maintenance.

[0093] In some embodiments, the effect evaluation module may also consider the impact of propeller self-cleaning or propeller polishing when calculating the fuel-saving rate. As the core component of the propeller, the surface fouling and roughness of the propeller have a decisive impact on propulsion efficiency. If, during dry-docking, in addition to applying energy-saving technologies to the underwater hull surface, the propeller is also polished or coated with antifouling paint, the overall fuel-saving effect will include the contribution of improved propeller efficiency. To differentiate the effects of hull surface energy-saving technologies and propeller energy-saving technologies, the effect evaluation module utilizes an open-water efficiency analysis model. By collecting shaft power, rotational speed, and ship speed, the actual open-water efficiency of the propeller at different times is estimated. If a significant improvement in propeller efficiency is found during the evaluation period, this improvement can be converted into corresponding fuel savings and separated from the total fuel-saving rate, thus obtaining the pure fuel-saving rate of the underwater hull surface energy-saving technology. This refined ship-propeller energy-saving effect separation technology represents the highest level of professionalism in the field of actual ship energy efficiency evaluation.

[0094] Example 3

[0095] To illustrate the application of this application in practical engineering more intuitively, a specific case study evaluating the effectiveness of its application on a real ship is provided below.

[0096] Suppose we consider a 150,000-ton oil tanker as the subject of this evaluation. During dry-docking repairs, its underwater hull surface was coated with a propeller-coated paint (i.e., underwater surface energy-saving technology was applied). To evaluate the actual fuel-saving effect of this paint, the system and method described in the embodiments of this application are used for evaluation.

[0097] S1. Collect raw operating data for the tanker one year before the coating construction (reference period) and one year after the coating construction (evaluation period); the raw data includes 730 sets of raw data such as speed, main engine speed, daily fuel consumption, slip rate, weather and sea conditions, and loading status.

[0098] S2. Establish a three-level operating condition system. For the speed range, since the oil tanker has a low speed, the interval is set to 1 knot.

[0099] S3. Standardize and clean the raw data, determine sample size, and unify format. From the two years of data (reference and evaluation periods), 240 sets of data were identified and removed due to severe sea states, abnormal parameters, and non-navigation status, leaving 490 sets of valid data. The sample size for each sub-condition was greater than or equal to 10 valid navigation days. After rigorous cleaning, high-quality steady-state navigation data was obtained and matched to the corresponding sub-conditions.

[0100] S4. Calculate the core parameters such as the operating percentage, theoretical number of days, and average daily fuel consumption for each working condition according to the formula of this invention, wherein:

[0101] ;

[0102] ;

[0103] ;

[0104] ;

[0105] ;

[0106] ;

[0107] .

[0108] S5. To explore the energy-saving effect of underwater energy-saving technology at different speeds, the fuel-saving rate in different speed ranges can be calculated based on the above parameters. Here, only the fuel-saving rate calculation for annual comprehensive operating conditions is shown, as follows:

[0109] ;

[0110] ;

[0111] ;

[0112] S6. Finally, regarding speed ( ) - Main engine speed ( - Fuel consumption ( Cross-validation was conducted based on the consistent correlation among the three factors; a standardized evaluation report was output, determining that the propeller coating technology achieves an annual comprehensive fuel saving rate of approximately 2.58% for a 150,000-ton oil tanker.

[0113] In addition to the above-described embodiments for oil tankers, the systems and methods of this application can also be applied to other types of ships, requiring only corresponding parameter adjustments during setup and data cleaning.

Claims

1. A method for evaluating the effectiveness of underwater surface energy-saving technology for ships, characterized in that, The method includes: Collect raw operational data of the target vessel during the reference period and the evaluation period, which are the operational phases before and after the application of underwater surface energy-saving technology, respectively; A three-level assessment condition system is established, comprising Level 1 period condition, Level 2 loading condition, and Level 3 speed range condition. The Level 1 period condition is divided according to the reference period and the assessment period, the Level 2 loading condition is divided according to the ship's loading status, and the Level 3 speed range condition is divided according to the ship type. The original operational data is standardized and cleaned, sample size is determined and format is unified, abnormal operating condition data is removed, and the cleaned data is matched to the corresponding sub-operating condition according to the three-level evaluation operating condition system. Based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges is calculated to evaluate the actual ship application effect of the underwater surface energy saving technology.

2. The method according to claim 1, characterized in that, The original operational data includes sailing date, sailing speed, main engine speed, daily fuel consumption, daily sailing distance, daily sailing time, no-load or light-load status, heavy-load status, slip rate, weather and sea conditions, ship operating status, sailing water conditions, and abnormal operating condition data.

3. The method according to claim 1, characterized in that, The reference period and the evaluation period are both set to a period of one year from the end of the ship's dry dock repair.

4. The method according to claim 1, characterized in that, The secondary loading condition includes: Heavy load condition refers to the state in which a ship is loaded with cargo up to its design heavy load draft. Unloaded or lightly loaded conditions refer to the ship sailing without cargo or in a state of light-load design draft.

5. The method according to claim 1, characterized in that, The three-level speed range operating conditions are based on the ship type, with speeds divided into intervals of 0.5 knots, 1 knot, or 2 knots. For speed ranges with an operating rate of less than one percent, they are merged into adjacent speed ranges.

6. The method according to claim 1, characterized in that, The standardized cleaning includes removing data under at least one of the following abnormal conditions: low visibility navigation, shallow water navigation, narrow waterway navigation, or abnormal navigation conditions.

7. The method according to claim 1, characterized in that, The steps for calculating the annual theoretical operating indicators include: Calculate the percentage of operating days for the target vessel during the reference and assessment periods based on the original operating data; calculate the average percentage of operating days for the target vessel under light / heavy load conditions during the reference and assessment periods based on the original operating data; calculate the annual theoretical effective sailing days based on the average percentage of operating days under light / heavy load conditions. Based on the cleaned operational data, calculate the percentage of operating days for the target vessel under light and heavy load conditions in each speed range during the reference and evaluation periods; calculate the average speed, average main engine speed, and average daily fuel consumption of the target vessel under light and heavy load conditions in different speed ranges during the reference and evaluation periods; and calculate the daily fuel savings, average daily fuel consumption, and average daily fuel savings under light and heavy load conditions based on the average daily fuel consumption and the percentage of operating days for each speed range.

8. The method according to claim 1, characterized in that, The formula for calculating the fuel saving rate under annual comprehensive operating conditions is as follows: ； ； in, y r This indicates the fuel saving rate under comprehensive annual operating conditions. y s This represents the theoretical fuel savings under comprehensive annual operating conditions, while the positive value represents the actual total fuel savings. y Rc This represents the annual comprehensive theoretical fuel consumption for the reference period; g B This indicates the theoretical number of days per year under light load conditions. g L This indicates the theoretical number of days per year under heavy load conditions. AsA B This indicates the average daily fuel consumption under light load conditions during the reference period. AsA L This indicates the average daily fuel consumption under heavy load conditions during the reference period. RcA B This indicates the average daily fuel consumption under light load conditions during the reference period. RcA L This indicates the average daily fuel consumption under heavy load conditions during the reference period.

9. The method according to claim 1, characterized in that, The formulas for calculating the fuel-saving rate at different speed ranges under light and heavy load conditions are as follows: ； in, This indicates the fuel saving rate at different speed ranges under light load conditions. This indicates the average daily fuel savings under light load conditions at different speed ranges during the evaluation period. This indicates the average daily fuel consumption at different speed ranges under light load conditions during the reference period. This indicates the fuel saving rate at different speed ranges under heavy load conditions. This indicates the average daily fuel savings under heavy load conditions at different speed ranges during the evaluation period. This indicates the average daily fuel consumption at different speed ranges under heavy load conditions during the reference period.

10. An evaluation system for the practical application effect of underwater surface energy-saving technology on ships, characterized in that, include: The data collection module is used to collect raw operational data of the target vessel during the reference period and the evaluation period, which are the operational stages before and after the application of underwater surface energy-saving technology, respectively. The working condition construction module is used to build a three-level evaluation working condition system, including the first-level period working condition, the second-level loading working condition, and the third-level speed range working condition. The first-level period working condition is divided according to the reference period and the evaluation period, the second-level loading working condition is divided according to the ship loading status, and the third-level speed range working condition is divided according to the ship type. The data processing module is used to standardize and clean the original operational data, determine the sample size and format, remove abnormal operating condition data, and match the cleaned data to the corresponding sub-operating condition according to the three-level evaluation operating condition system. The effect evaluation module is used to calculate the fuel saving rate of the evaluation period relative to the reference period under the annual comprehensive operating conditions and different speed ranges based on the annual theoretical operating indicators of the reference period and the evaluation period under the corresponding sub-operating conditions, so as to evaluate the actual ship application effect of the underwater surface energy saving technology.

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