A method for monitoring energy efficiency of a high-temperature fresh water cooling system of a marine main engine

Abstract

A kind of energy efficiency monitoring method of marine main engine high-temperature fresh water cooling system, including energy efficiency evaluation process, fault monitoring process and heat exchanger judging process, each process is based on the collection data of main engine, heat exchanger, water pump, first calculate energy efficiency, then energy efficiency and corresponding working condition are as the basic unit of historical database, when application, first, according to the working condition data, the data in historical database is filtered, to select the data required when energy efficiency evaluation process, fault monitoring process, heat exchanger judging process is carried out, then corresponding threshold value is judged, to realize energy efficiency evaluation, whether fault, fault type, heat exchanger fault judgment etc..The design not only can monitor the energy efficiency of marine main engine high-temperature fresh water cooling system, but also can reduce energy consumption loss, facilitate routine maintenance.

Description

Technical Field

[0001] This invention relates to a monitoring technology for ship systems, belonging to the field of energy efficiency monitoring and evaluation, and particularly to a method for monitoring the energy efficiency of a ship's main engine high-temperature freshwater cooling system. Background Technology

[0002] Currently, the high-temperature freshwater cooling system of ship main engines consumes a large amount of electrical energy during operation. The energy efficiency of the high-temperature freshwater cooling system of ship main engines will directly affect the energy efficiency level of the ship. Moreover, during the operation of the ship, due to factors such as scaling in the cooling chamber of the ship main engine and the cooling channel of the heat exchanger, the energy efficiency of the high-temperature freshwater cooling system of ship main engines may decrease. Therefore, corresponding energy efficiency monitoring is required.

[0003] However, due to the lack of monitoring methods for the energy efficiency of the ship's main engine high-temperature freshwater cooling system, effective energy efficiency data cannot be obtained, making it impossible to determine the changes in the energy efficiency level of the ship's main engine high-temperature freshwater cooling system after a period of operation. Therefore, it is impossible to guide the engineers to carry out scientific maintenance of the ship's main engine high-temperature freshwater cooling system in order to reduce the energy loss of the ship's main engine high-temperature freshwater cooling system.

[0004] Therefore, it is necessary to design an effective monitoring system and method for the high-temperature freshwater cooling system of the ship's main engine in order to obtain effective monitoring data and use it for subsequent processing, such as energy efficiency assessment, main engine fault diagnosis, heat exchanger diagnosis, etc., in order to monitor the energy efficiency level of the high-temperature freshwater cooling system of the ship's main engine, quickly identify the faults in the system, and scientifically design the cooling system based on the monitoring data.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this patent application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects and problems in the existing technology that cannot monitor the energy efficiency of the high-temperature fresh water cooling system of the ship's main engine, and to provide a method for monitoring the energy efficiency of the high-temperature fresh water cooling system of the ship's main engine.

[0007] To achieve the above objectives, the technical solution of the present invention is: an energy efficiency monitoring method for a high-temperature freshwater cooling system for a marine main engine, wherein the high-temperature freshwater cooling system for a marine main engine includes a marine main engine and a heat exchanger, and the marine main engine includes a cylinder bore and a cylinder liner disposed therein.

[0008] The cooling water outlet of the ship's main engine is connected to the high-temperature water inlet of the heat exchanger via a high-temperature pipeline, and the high-temperature water outlet of the heat exchanger is connected to the cooling water inlet of the ship's main engine via a low-temperature pipeline. A water pump is installed on the low-temperature pipeline. The high-temperature water inlet of the heat exchanger is connected to the high-temperature water outlet of the heat exchanger via a return water pipeline, and the low-temperature water outlet of the heat exchanger is connected to the low-temperature water inlet of the heat exchanger after passing through a first heat exchange pipeline, an external cold source, and a second heat exchange pipeline in sequence.

[0009] The energy efficiency monitoring method includes an energy efficiency assessment process, which includes the following steps:

[0010] 101: Collect real-time operating data of the ship's main engine and heat exchangers. This real-time operating data includes: main engine speed n, torque Me, power Ne, main engine exhaust temperature t, real-time flow rate G of cylinder liner cooling water, main engine inlet temperature T1 and main engine outlet temperature T2 corresponding to the cooling water inlet and outlet on the main engine; high temperature inlet temperature T3, high temperature outlet temperature T4, low temperature outlet temperature T5, and low temperature inlet temperature T6 corresponding to the high temperature water inlet, high temperature water outlet, low temperature water outlet, and low temperature water inlet on the heat exchanger; collect the heat exchanger return water flow rate q on the return water pipeline; and the input electrical energy P1 of the No. 1 water pump.

[0011] 102: Calculate the heat exchange of the ship's main engine Q = c * G(T1 - T2), where c is the known specific heat capacity of the cooling water in the cylinder liner; at the same time, take the input electrical energy P1 as the input electrical energy P of the entire cooling system; then, calculate the energy efficiency index η of the ship's main engine high-temperature fresh water cooling system, with the formula: η = Q / P.

[0012] 103: The energy efficiency index and its corresponding host operating conditions are stored as a set of historical data in the historical database. The host operating conditions include host speed n, torque Me, and power Ne. The historical data is continuously collected and continuously stored in the historical database.

[0013] 104: When it is necessary to evaluate energy efficiency in the future, first obtain the energy efficiency index and the corresponding host operating conditions at the time or stage to be evaluated according to the above method. Then, find the historical energy efficiency index corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. If there are two or more historical energy efficiency indices, take the average value. Then compare the energy efficiency index at the time or stage to be evaluated with the historical energy efficiency index or its average value. When the absolute value of the difference exceeds the evaluation threshold, it is determined that the energy efficiency of the cooling system has changed.

[0014] A main unit inlet temperature sensor is installed on the low-temperature pipe next to the cooling water inlet, a main unit outlet temperature sensor and a main unit flow meter are installed on the high-temperature pipe next to the cooling water outlet, a high-temperature inlet temperature sensor is installed on the high-temperature pipe next to the high-temperature water inlet, a high-temperature outlet temperature sensor is installed on the low-temperature pipe next to the high-temperature water outlet, a return water flow meter is installed on the return water pipe, a low-temperature inlet temperature sensor is installed on the second heat exchange pipe next to the low-temperature water inlet, and a low-temperature outlet temperature sensor is installed on the first heat exchange pipe next to the low-temperature water outlet.

[0015] The energy efficiency index and its corresponding host operating condition for the stage to be evaluated refer to:

[0016] First, select the operating condition data that appears most frequently in the operating condition data corresponding to the stage to be evaluated as the host operating condition of the stage to be evaluated. Then, select multiple corresponding energy efficiency indices from them, and then calculate the average value as the energy efficiency index of the stage to be evaluated.

[0017] The energy efficiency monitoring method further includes a fault monitoring process, which includes the following steps:

[0018] 201: Collect the main unit inlet temperature T1, main unit exhaust temperature t, and corresponding main unit operating conditions at the time or stage to be monitored;

[0019] 202: First, find the main engine inlet temperature and exhaust gas temperature corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. Then, calculate the average value T_average of the main engine inlet temperature and the average value t_average of the main engine exhaust gas temperature. Then, compare the main engine inlet temperature T1 to be monitored with T_average. If the absolute value of the difference is less than or equal to the inlet temperature threshold, it is determined that the ship's main engine is not faulty and the monitoring ends. If it is greater than the inlet temperature threshold, it is determined that the ship's main engine is faulty and the next step is performed.

[0020] 203: Compare the main engine exhaust temperature t to be monitored with the average t. If the absolute value of the difference is less than or equal to the exhaust temperature threshold, the fault type is determined to be a problem with the heat transfer performance of the ship's main engine, such as scale buildup. If it is greater than the exhaust temperature threshold, the fault type is determined to be a problem with the combustion conditions of the ship's main engine.

[0021] The host inlet temperature T1, host exhaust temperature t, and their corresponding host operating conditions during the monitoring phase refer to: first, selecting the most frequently occurring operating condition data from the operating condition data corresponding to the monitoring phase as the host operating conditions during the monitoring phase; then, selecting multiple corresponding host inlet temperatures T1 and host exhaust temperatures t from these data; and finally, calculating their average values ​​as the host inlet temperature T1 and host exhaust temperature t during the monitoring phase.

[0022] The energy efficiency monitoring method also includes a heat exchanger judgment process, which includes the following steps:

[0023] 301: Collect the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of the heat exchanger at the time or stage to be judged, as well as the corresponding main unit operating conditions.

[0024] 302: First, calculate the temperature difference between the high-temperature inlet and outlet of the heat exchanger, Thigh-temperature difference = (T3 - T4). Then, filter out the primary data that is the same as Thigh-temperature difference from the historical data. Then, filter out the secondary data that is the same as the temperature difference between the low-temperature inlet and outlet of the heat exchanger, Tlow-temperature difference = (T5 - T6) from the primary data. Then, filter out the corresponding return water flow rate q from the secondary data. Then, calculate the average to obtain the average return water flow rate qaverage.

[0025] 303: First, compare the heat exchanger return water flow rate q of the stage to be judged with q average. If the absolute value of the difference is less than or equal to the judgment threshold, the heat exchanger is judged to be fault-free. If it is greater than the judgment threshold, the heat exchanger is judged to be faulty.

[0026] The high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of the heat exchanger in the stage to be judged, as well as the corresponding main unit operating conditions, refer to the following: First, select the operating condition data that appears most frequently in the corresponding operating condition data of the stage to be judged as the main unit operating conditions of the stage to be judged. Then, filter out the high-temperature inlet temperature, high-temperature outlet temperature, low-temperature inlet temperature, low-temperature outlet temperature, and return water flow rate of multiple heat exchangers. Then, calculate the average value of each of them as the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, and return water flow rate q of the heat exchanger in the stage to be judged.

[0027] The temperature of the main unit outlet temperature T2 is 70℃-85℃.

[0028] The historical data is continuously collected and stored in the historical database within one month of the ship leaving the factory and starting its voyage.

[0029] The low-temperature pipeline is also equipped with a second water pump connected in parallel with the first water pump. The input electrical energy of the second water pump is P2. At this time, the sum of the input electrical energy of the first water pump and the second water pump is taken as the input electrical energy P of the entire cooling system, P = P1 + P2.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. In the energy efficiency monitoring method of a high-temperature freshwater cooling system for a marine main engine, the ratio of the heat exchange capacity Q of the main engine to the input electrical energy P of the entire cooling system is used as the energy efficiency index η of the high-temperature freshwater cooling system. This allows for monitoring of the energy efficiency of the system. Simultaneously, the energy efficiency values ​​(including simultaneously collected operating data from the main engine, heat exchangers, water pumps, etc.) and the corresponding main engine operating conditions are stored as a set of historical data in a historical database. This data is continuously collected and input, serving as the basis for subsequent processes, including but not limited to energy efficiency assessment, main engine fault diagnosis, and heat exchanger fault diagnosis. This allows for real-time and comprehensive monitoring of the entire cooling system's operation, facilitating maintenance and reducing energy loss. Therefore, this invention not only monitors the energy efficiency of a high-temperature freshwater cooling system for a marine main engine but also reduces energy loss and facilitates routine maintenance.

[0032] 2. In the energy efficiency monitoring method of a high-temperature freshwater cooling system for a marine main engine according to the present invention, when performing fault monitoring of the marine main engine, it can not only determine whether a fault has occurred, but also determine the type of fault. Specifically, in the judgment process, the main engine inlet temperature is compared first, and then the main engine exhaust temperature is compared. The reason for this limitation is that if the main engine outlet temperature remains constant, then under unchanged operating conditions, a change in the main engine inlet temperature can directly indicate a fault in the marine main engine. Then, the exhaust temperature is used to further determine whether the change is due to a change in the combustion conditions within the main engine cylinder liner or a change in the heat transfer performance of the main engine. This method is not only easy to operate and highly intuitive, but also less prone to errors and has high accuracy. Therefore, the present invention can not only determine main engine faults, but also has high accuracy and is easy to operate.

[0033] 3. In the energy efficiency monitoring method for a high-temperature freshwater cooling system of a ship's main engine, this invention not only determines whether a heat exchanger is malfunctioning when judging its operating status, but also limits the order of judgment. Specifically, it first compares the temperature difference between the high-temperature inlet and outlet of the heat exchanger, then compares the temperature difference between the low-temperature inlet and outlet, and finally compares the return water flow rate. The advantage of this limitation is that it avoids misleading results from malfunctions in the low-temperature freshwater circulation or seawater cooling side of the heat exchanger (external cold source and its piping). Otherwise, if the temperature difference between the low-temperature inlet and outlet is selected first, the initial data may be incorrect, thus reducing the final judgment accuracy. Therefore, this invention provides a more accurate assessment of heat exchanger malfunctions. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the present invention.

[0035] Figure 2 This is a flowchart of the energy efficiency assessment process in this invention.

[0036] Figure 3 This is a flowchart of the fault monitoring process in this invention.

[0037] Figure 4 This is a flowchart of the heat exchanger judgment process in this invention.

[0038] In the diagram: Main engine 1, Cooling water outlet 11, Cooling water inlet 12, High-temperature pipe 13, Low-temperature pipe 14, Main engine inlet temperature sensor 2, Main engine outlet temperature sensor 3, Main engine flow meter 4, Heat exchanger 5, High-temperature water inlet 51, High-temperature water outlet 52, Low-temperature water outlet 53, Low-temperature water inlet 54, Return water pipe 55, Heat exchanger No. 1 pipe 56, External cold source 57, Heat exchanger No. 2 pipe 58, High-temperature inlet temperature sensor 6, High-temperature outlet temperature sensor 7, Low-temperature outlet temperature sensor 8, Low-temperature inlet temperature sensor 9, Return water flow meter 10, Pump No. 1 A, Pump No. 2 B. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] See Figure 1 — Figure 4 A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine, wherein the high-temperature freshwater cooling system for the marine main engine includes a marine main engine 1 and a heat exchanger 5, and the marine main engine 1 includes a cylinder bore and a cylinder liner disposed therein.

[0041] The cooling water outlet 11 on the main engine 1 is connected to the high-temperature water inlet 51 of the heat exchanger 5 via a high-temperature pipe 13. The high-temperature water outlet 52 of the heat exchanger 5 is connected to the cooling water inlet 12 on the main engine 1 via a low-temperature pipe 14. A first water pump A is installed on the low-temperature pipe 14. The high-temperature water inlet 51 on the heat exchanger 5 is connected to the high-temperature water outlet 52 of the heat exchanger 5 via a return water pipe 55. The low-temperature water outlet 53 on the heat exchanger 5 is connected to the low-temperature water inlet 54 on the heat exchanger 5 via a first heat exchange pipe 56, an external cold source 57, and a second heat exchange pipe 58.

[0042] The energy efficiency monitoring method includes an energy efficiency assessment process, which includes the following steps:

[0043] 101: Collect real-time operating data of the ship's main engine 1 and heat exchanger 5. This real-time operating data includes: main engine speed n, torque Me, power Ne, main engine exhaust temperature t, real-time flow rate G of cylinder liner cooling water, main engine inlet temperature T1 and main engine outlet temperature T2 corresponding to cooling water inlet 12 and cooling water outlet 11 on the ship's main engine 1; high temperature inlet temperature T3, high temperature outlet temperature T4, low temperature outlet temperature T5, and low temperature inlet temperature T6 corresponding to high temperature water inlet 51, high temperature water outlet 52, low temperature water outlet 53, and low temperature water inlet 54 on the heat exchanger 5; collect the return water flow rate q of the heat exchanger 5 on the return water pipe 55; and the input electrical energy P1 of the No. 1 water pump A.

[0044] 102: Calculate the heat exchange of the main engine 1, Q = c * G(T1 - T2), where c is the known specific heat capacity of the cooling water in the cylinder liner; at the same time, take the input electrical energy P1 as the input electrical energy P of the entire cooling system; then, calculate the energy efficiency index η of the high-temperature fresh water cooling system of the main engine, with the formula: η = Q / P.

[0045] 103: The energy efficiency index and its corresponding host operating conditions are stored as a set of historical data in the historical database. The host operating conditions include host speed n, torque Me, and power Ne. The historical data is continuously collected and continuously stored in the historical database.

[0046] 104: When it is necessary to evaluate energy efficiency in the future, first obtain the energy efficiency index and the corresponding host operating conditions at the time or stage to be evaluated according to the above method. Then, find the historical energy efficiency index corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. If there are two or more historical energy efficiency indices, take the average value. Then compare the energy efficiency index at the time or stage to be evaluated with the historical energy efficiency index or its average value. When the absolute value of the difference exceeds the evaluation threshold, it is determined that the energy efficiency of the cooling system has changed.

[0047] A main unit inlet temperature sensor 2 is installed on the low-temperature pipe 14 next to the cooling water inlet 12; a main unit outlet temperature sensor 3 and a main unit flow meter 4 are installed on the high-temperature pipe 13 next to the cooling water outlet 11; a high-temperature inlet temperature sensor 6 is installed on the high-temperature pipe 13 next to the high-temperature water inlet 51; a high-temperature outlet temperature sensor 7 is installed on the low-temperature pipe 14 next to the high-temperature water outlet 52; a return water flow meter 10 is installed on the return water pipe 55; a low-temperature inlet temperature sensor 9 is installed on the second heat exchange pipe 58 next to the low-temperature water inlet 54; and a low-temperature outlet temperature sensor 8 is installed on the first heat exchange pipe 56 next to the low-temperature water outlet 53.

[0048] The energy efficiency index and its corresponding host operating condition for the stage to be evaluated refer to:

[0049] First, select the operating condition data that appears most frequently in the operating condition data corresponding to the stage to be evaluated as the host operating condition of the stage to be evaluated. Then, select multiple corresponding energy efficiency indices from them, and then calculate the average value as the energy efficiency index of the stage to be evaluated.

[0050] The energy efficiency monitoring method further includes a fault monitoring process, which includes the following steps:

[0051] 201: Collect the main unit inlet temperature T1, main unit exhaust temperature t, and corresponding main unit operating conditions at the time or stage to be monitored;

[0052] 202: First, find the main engine inlet temperature and exhaust gas temperature corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. Then, calculate the average value T_average of the main engine inlet temperature and the average value t_average of the main engine exhaust gas temperature. Then, compare the main engine inlet temperature T1 to be monitored with T_average. If the absolute value of the difference is less than or equal to the inlet temperature threshold, it is determined that the ship's main engine 1 is fault-free and the monitoring ends. If it is greater than the inlet temperature threshold, it is determined that the ship's main engine 1 is faulty and proceed to the next step.

[0053] 203: Compare the main engine exhaust temperature t to be monitored with the average t. If the absolute value of the difference is less than or equal to the exhaust temperature threshold, the fault type is determined to be a problem with the heat transfer performance of the main engine 1, such as scale buildup. If it is greater than the exhaust temperature threshold, the fault type is determined to be a problem with the combustion condition of the main engine 1.

[0054] The host inlet temperature T1, host exhaust temperature t, and their corresponding host operating conditions during the monitoring phase refer to: first, selecting the most frequently occurring operating condition data from the operating condition data corresponding to the monitoring phase as the host operating conditions during the monitoring phase; then, selecting multiple corresponding host inlet temperatures T1 and host exhaust temperatures t from these data; and finally, calculating their average values ​​as the host inlet temperature T1 and host exhaust temperature t during the monitoring phase.

[0055] The energy efficiency monitoring method also includes a heat exchanger judgment process, which includes the following steps:

[0056] 301: Collect the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of heat exchanger 5 at the time or stage to be judged, as well as the corresponding main unit operating conditions.

[0057] 302: First, calculate the temperature difference Thigh temperature difference between the high temperature inlet and outlet of heat exchanger 5 = (T3 - T4). Then, filter out the primary data that is the same as Thigh temperature difference from the historical data. Then, filter out the secondary data that is the same as Tlow temperature difference between the low temperature inlet and outlet of heat exchanger 5 = (T5 - T6) from the primary data. Then, filter out the corresponding return water flow rate q from the secondary data. Then, calculate the average to obtain the average return water flow rate qaverage.

[0058] 303: First, compare the return water flow rate q of heat exchanger 5 in the stage to be judged with the average q. If the absolute value of the difference is less than or equal to the judgment threshold, then heat exchanger 5 is judged to be without fault. If it is greater than the judgment threshold, then heat exchanger 5 is judged to be faulty.

[0059] The high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of the heat exchanger 5 in the stage to be judged, and the corresponding main unit operating conditions, refer to the following: First, select the operating condition data that appears most frequently in the operating condition data corresponding to the stage to be judged as the main unit operating conditions in the stage to be judged. Then, select multiple high-temperature inlet temperature, high-temperature outlet temperature, low-temperature inlet temperature, low-temperature outlet temperature, and return water flow rate of the corresponding heat exchanger 5 from them. Then, calculate the average value of each value as the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, and return water flow rate q of the heat exchanger 5 in the stage to be judged.

[0060] The temperature of the main unit outlet temperature T2 is 70℃-85℃.

[0061] The historical data is continuously collected and stored in the historical database within one month of the ship leaving the factory and starting its voyage.

[0062] The low-temperature pipeline 14 is also equipped with a second water pump B connected in parallel with the first water pump A. The input electrical energy of the second water pump B is P2. At this time, the sum of the input electrical energy of the first water pump A and the second water pump B is taken as the input electrical energy P of the entire cooling system, P = P1 + P2.

[0063] The principle of this invention is explained as follows:

[0064] The cylinder liner in this invention is part of the ship's main engine 1 (mainly a diesel engine). The cylinder liner is a cylindrical part that is placed in the cylinder bore of the ship's main engine 1 and is pressed and fixed by the cylinder head. The piston reciprocates in its inner bore and is cooled by cooling water.

[0065] In this invention, the main engine operating data (including speed, torque, and power) and exhaust gas temperature are measured by measuring instruments installed on the ship's main engine 1, and the measurement data are constantly changing.

[0066] For historical databases, this invention assumes that the cooling system of the ship is fault-free and working normally within the first month after leaving the factory.

[0067] The working condition data interpolation in this invention refers to: first finding similar data, and then using the interpolation method to obtain the working condition data.

[0068] Example 1:

[0069] See Figure 1 — Figure 2 A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine, wherein the high-temperature freshwater cooling system for the marine main engine includes a marine main engine 1 and a heat exchanger 5, and the marine main engine 1 includes a cylinder bore and a cylinder liner disposed therein.

[0070] The cooling water outlet 11 on the main engine 1 is connected to the high-temperature water inlet 51 of the heat exchanger 5 via a high-temperature pipe 13. The high-temperature water outlet 52 of the heat exchanger 5 is connected to the cooling water inlet 12 on the main engine 1 via a low-temperature pipe 14. A first water pump A is installed on the low-temperature pipe 14. The high-temperature water inlet 51 on the heat exchanger 5 is connected to the high-temperature water outlet 52 of the heat exchanger 5 via a return water pipe 55. The low-temperature water outlet 53 on the heat exchanger 5 is connected to the low-temperature water inlet 54 on the heat exchanger 5 via a first heat exchange pipe 56, an external cold source 57, and a second heat exchange pipe 58.

[0071] The energy efficiency monitoring method includes an energy efficiency assessment process, which includes the following steps:

[0072] 101: Collect real-time operating data of the ship's main engine 1 and heat exchanger 5. This real-time operating data includes: main engine speed n, torque Me, power Ne, main engine exhaust temperature t, real-time flow rate G of cylinder liner cooling water, main engine inlet temperature T1 and main engine outlet temperature T2 corresponding to cooling water inlet 12 and cooling water outlet 11 on the ship's main engine 1; high temperature inlet temperature T3, high temperature outlet temperature T4, low temperature outlet temperature T5, and low temperature inlet temperature T6 corresponding to high temperature water inlet 51, high temperature water outlet 52, low temperature water outlet 53, and low temperature water inlet 54 on the heat exchanger 5; collect the return water flow rate q of the heat exchanger 5 on the return water pipe 55; and the input electrical energy P1 of the No. 1 water pump A.

[0073] 102: Calculate the heat exchange of the main engine 1, Q = c * G(T1 - T2), where c is the known specific heat capacity of the cooling water in the cylinder liner; at the same time, take the input electrical energy P1 as the input electrical energy P of the entire cooling system; then, calculate the energy efficiency index η of the high-temperature fresh water cooling system of the main engine, with the formula: η = Q / P.

[0074] 103: The energy efficiency index and its corresponding host operating conditions are stored as a set of historical data in the historical database. The host operating conditions include host speed n, torque Me, and power Ne. The historical data is continuously collected and continuously stored in the historical database.

[0075] 104: When subsequent energy efficiency assessments are required, first obtain the energy efficiency index and its corresponding host operating conditions at the time or stage to be assessed using the method described above. Then, search the historical database for historical energy efficiency indices corresponding to interpolated data with consistent or similar operating conditions. If there are two or more historical energy efficiency indices, take their average value. Then, compare the energy efficiency index at the time or stage to be assessed with the historical energy efficiency index or its average value. When the absolute value of the difference exceeds the assessment threshold, it is determined that the energy efficiency of the cooling system has changed. The assessment threshold is preferably 1%–3%, and more preferably 2%.

[0076] Example 2:

[0077] The basic content is the same as in Example 1, except that:

[0078] See Figure 3 The energy efficiency monitoring method further includes a fault monitoring process, which includes the following steps:

[0079] 201: Collect the main unit inlet temperature T1, the main unit exhaust temperature t, and the corresponding main unit operating conditions at the time or stage to be monitored;

[0080] 202: First, find the main engine inlet temperature and exhaust gas temperature corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. Then, calculate the average value T_average of the main engine inlet temperature and the average value t_average of the main engine exhaust gas temperature. Then, compare the main engine inlet temperature T1 to be monitored with T_average. If the absolute value of the difference is less than or equal to the inlet temperature threshold, it is determined that the ship's main engine 1 is fault-free and the monitoring ends. If it is greater than the inlet temperature threshold, it is determined that the ship's main engine 1 is faulty and proceed to the next step.

[0081] 203: Compare the monitored main engine exhaust temperature t with the average t. If the absolute value of the difference is less than or equal to the exhaust temperature threshold, the fault type is determined to be a problem with the heat transfer performance of the ship's main engine 1, such as scale buildup. If it is greater than the exhaust temperature threshold, the fault type is determined to be a problem with the combustion conditions of the ship's main engine 1. The exhaust temperature threshold is 1℃–3℃.

[0082] Example 3:

[0083] The basic content is the same as in Example 1, except that:

[0084] See Figure 4 The energy efficiency monitoring method further includes a heat exchanger judgment process, which includes the following steps:

[0085] 301: Collect the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of heat exchanger 5 at the time or stage to be judged, as well as the corresponding main unit operating conditions.

[0086] 302: First, calculate the temperature difference Thigh temperature difference between the high temperature inlet and outlet of heat exchanger 5 = (T3 - T4). Then, filter out the primary data that is the same as Thigh temperature difference from the historical data. Then, filter out the secondary data that is the same as Tlow temperature difference between the low temperature inlet and outlet of heat exchanger 5 = (T5 - T6) from the primary data. Then, filter out the corresponding return water flow rate q from the secondary data. Then, calculate the average to obtain the average return water flow rate qaverage.

[0087] 303: First, compare the return water flow rate q of heat exchanger 5 in the stage to be judged with the average q. If the absolute value of the difference is less than or equal to the judgment threshold, then heat exchanger 5 is judged to be fault-free; if it is greater than the judgment threshold, then heat exchanger 5 is judged to be faulty. The judgment threshold is preferably 8%-15%, and more preferably 10%.

[0088] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine, the high-temperature freshwater cooling system comprising a marine main engine (1) and a heat exchanger (5), the marine main engine (1) comprising a cylinder bore and a cylinder liner disposed therein, characterized in that: The cooling water outlet (11) on the main engine (1) of the ship is connected to the high-temperature water inlet (51) of the heat exchanger (5) via a high-temperature pipe (13). The high-temperature water outlet (52) of the heat exchanger (5) is connected to the cooling water inlet (12) on the main engine (1) via a low-temperature pipe (14). A first water pump (A) is installed on the low-temperature pipe (14). The high-temperature water inlet (51) on the heat exchanger (5) is connected to the high-temperature water outlet (52) of the heat exchanger (5) via a return water pipe (55). The low-temperature water outlet (53) on the heat exchanger (5) is connected to the low-temperature water inlet (54) on the heat exchanger (5) via a first heat exchange pipe (56), an external cold source (57), and a second heat exchange pipe (58) in sequence. The energy efficiency monitoring method includes an energy efficiency assessment process, which includes the following steps: 101: Collect real-time operating data of the ship's main engine (1) and heat exchanger (5). The real-time operating data includes: main engine speed n, torque Me, power Ne, main engine exhaust temperature t, real-time flow rate G of cylinder liner cooling water, main engine inlet temperature T1 and main engine outlet temperature T2 corresponding to the cooling water inlet (12) and cooling water outlet (11) on the ship's main engine (1); high temperature inlet temperature T3, high temperature outlet temperature T4, low temperature outlet temperature T5, and low temperature inlet temperature T6 corresponding to the high temperature water inlet (51), high temperature water outlet (52), low temperature water outlet (53), and low temperature water inlet (54) on the heat exchanger (5); collect the return water flow rate q of the heat exchanger (5) on the return water pipe (55); and the input electrical energy P1 of the No. 1 water pump (A). 102: Calculate the heat exchange of the ship's main engine (1) Q = c * G(T1 - T2), where c is the known specific heat capacity of the cooling water in the cylinder liner; at the same time, take the input electrical energy P1 as the input electrical energy P of the entire cooling system; then, calculate the energy efficiency index η of the ship's main engine high-temperature fresh water cooling system, the formula is: η = Q / P. 103: The energy efficiency index and its corresponding host operating conditions are stored as a set of historical data in the historical database. The host operating conditions include host speed n, torque Me, and power Ne. The historical data is continuously collected and continuously stored in the historical database. 104: When it is necessary to evaluate energy efficiency in the future, first obtain the energy efficiency index and the corresponding host operating conditions at the time or stage to be evaluated according to the above method. Then, find the historical energy efficiency index corresponding to the interpolation of the operating condition data with the same or similar operating conditions in the historical database. If there are two or more historical energy efficiency indices, take the average value. Then compare the energy efficiency index at the time or stage to be evaluated with the historical energy efficiency index or its average value. When the absolute value of the difference exceeds the evaluation threshold, it is determined that the energy efficiency of the cooling system has changed.

2. The energy efficiency monitoring method for a high-temperature freshwater cooling system for a marine main engine according to claim 1, characterized in that: A main unit inlet temperature sensor (2) is installed on the low-temperature pipe (14) next to the cooling water inlet (12), a main unit outlet temperature sensor (3) and a main unit flow meter (4) are installed on the high-temperature pipe (13) next to the cooling water outlet (11), a high-temperature inlet temperature sensor (6) is installed on the high-temperature pipe (13) next to the high-temperature water inlet (51), a high-temperature outlet temperature sensor (7) is installed on the low-temperature pipe (14) next to the high-temperature water outlet (52), a return water flow meter (10) is installed on the return water pipe (55), a low-temperature inlet temperature sensor (9) is installed on the second heat exchange pipe (58) next to the low-temperature water inlet (54), and a low-temperature outlet temperature sensor (8) is installed on the first heat exchange pipe (56) next to the low-temperature water outlet (53).

3. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: The energy efficiency index at the time or stage to be evaluated and its corresponding host operating condition refer to: First, select the operating condition data that appears most frequently from the operating condition data corresponding to the time or stage to be evaluated, and use it as the host operating condition for the time or stage to be evaluated. Then, select multiple corresponding energy efficiency indices from them, and then calculate the average value as the energy efficiency index for the time or stage to be evaluated.

4. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: The energy efficiency monitoring method further includes a fault monitoring process, which includes the following steps: 201: Collect the main unit inlet temperature T1, main unit exhaust temperature t, and corresponding main unit operating conditions at the time or stage to be monitored; 202: First, find the host inlet temperature and exhaust gas temperature corresponding to the interpolation of consistent or similar operating conditions in the historical database, and then calculate the average value T of the host inlet temperature. 平均 The average value t of the exhaust gas temperature of the main unit 平均 Then, the inlet temperature T1 of the host to be monitored is compared with T... 平均 If the absolute value of the difference is less than or equal to the inlet temperature threshold, the ship's main engine (1) is deemed to be fault-free and the monitoring ends; if it is greater than the inlet temperature threshold, the ship's main engine (1) is deemed to be faulty and the next step is performed. 203: The flue gas temperature t of the main unit to be monitored is compared with t 平均 If the absolute value of the difference is less than or equal to the exhaust temperature threshold, the fault type is determined to be a problem with the heat transfer performance of the ship's main engine (1), such as scale buildup; if it is greater than the exhaust temperature threshold, the fault type is determined to be a problem with the combustion conditions of the ship's main engine (1).

5. The energy efficiency monitoring method for a high-temperature freshwater cooling system for a marine main engine according to claim 4, characterized in that: The host inlet temperature T1, host exhaust temperature t, and their corresponding host operating conditions at the time or stage to be monitored refer to: first, selecting the operating condition data that appears most frequently from the operating condition data corresponding to the time or stage to be monitored as the host operating condition at the time or stage to be monitored; then, selecting multiple corresponding host inlet temperatures T1 and host exhaust temperatures t from them; and finally, calculating the average value of each to be used as the host inlet temperature T1 and host exhaust temperature t at the time or stage to be monitored.

6. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: The energy efficiency monitoring method also includes a heat exchanger judgment process, which includes the following steps: 301: Collect the high temperature inlet temperature T3, high temperature outlet temperature T4, low temperature inlet temperature T5, low temperature outlet temperature T6, return water flow rate q of the heat exchanger (5) at the time or stage to be judged, as well as the corresponding main unit operating conditions. 302: First calculate the temperature difference T between the high-temperature inlet and outlet of the heat exchanger (5). 高温差 = (T3 - T4), then combine the historical data with T 高温差 The same data is filtered out, and then the data is filtered again to find the temperature difference T between the low temperature inlet and outlet of the heat exchanger (5). 低温差 = (T5-T6) identical quadratic data, then filter out the corresponding return water flow rate q from the quadratic data, and then calculate the average to obtain the average return water flow rate q. 平均 ; 303: First, determine the return water flow rate q of the heat exchanger (5) in the stage to be judged and q 平均 Compare the values. If the absolute value of the difference is less than or equal to the judgment threshold, the heat exchanger (5) is judged to be fault-free. If it is greater than the judgment threshold, the heat exchanger (5) is judged to be faulty.

7. The energy efficiency monitoring method for a high-temperature freshwater cooling system for a marine main engine according to claim 6, characterized in that: The high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, return water flow rate q of the heat exchanger (5) in the stage to be judged, and the corresponding main unit operating conditions refer to: firstly, in the operating condition data corresponding to the stage to be judged, select the operating condition data that appears most frequently as the main unit operating conditions of the stage to be judged, then filter out the high-temperature inlet temperature, high-temperature outlet temperature, low-temperature inlet temperature, low-temperature outlet temperature, and return water flow rate of multiple heat exchangers (5) in the stage to be judged, and then calculate the average value of each as the high-temperature inlet temperature T3, high-temperature outlet temperature T4, low-temperature inlet temperature T5, low-temperature outlet temperature T6, and return water flow rate q of the heat exchanger (5) in the stage to be judged.

8. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: The temperature of the main unit outlet temperature T2 is 70℃-85℃.

9. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: The historical data is continuously collected and stored in the historical database within one month of the ship leaving the factory and starting its voyage.

10. A method for monitoring the energy efficiency of a high-temperature freshwater cooling system for a marine main engine according to claim 1 or 2, characterized in that: A second water pump (B) is also installed on the low-temperature pipeline (14) in parallel with the first water pump (A). The input electrical energy of the second water pump (B) is P2. At this time, the sum of the input electrical energy of the first water pump (A) and the second water pump (B) is taken as the input electrical energy P of the entire cooling system, P = P1 + P2.

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