Active heat energy recovery system and method for ship

Abstract

The invention discloses an active heat energy recovery system and method for a ship. According to the system, an active constant-temperature energy storage unit serves as a core, an intelligent auxiliary heating unit, a heat energy distribution and waste heat recovery unit and a flue gas waste heat recovery unit are integrated, main engine cylinder sleeve water and flue gas heat energy are synchronously recovered through double waste heat direct supply paths, and efficient storage and dynamic adjustment of heat energy are achieved by means of a heat insulation and preservation structure and intelligent temperature control circulation. When the main engine is shut down or is in low load, heat is stably supplied by means of an energy storage cabin energy storage and auxiliary heating linkage mode. The problems that in the prior art, waste heat recovery is not comprehensive, the energy storage efficiency is low, and heat supply energy consumption is high and unstable under special working conditions are solved, the energy utilization rate is remarkably increased, the operation cost is reduced, and the system is suitable for various ship heat needing equipment and has extremely high practicability and economical efficiency.

Description

Technical Field

[0001] This invention relates to the field of marine power and energy conservation technology, specifically to an active heat recovery system and method for ships. Background Technology

[0002] During the operation of a ship's main engine, high-temperature heat energy from the cylinder liner water and flue gas heat energy reaching approximately 400°C are continuously generated. These two types of heat energy are important potential energy sources for ship operation. However, current technologies mostly only recover one type of waste heat, failing to fully utilize the heat energy resources generated during ship operation. Even some technologies attempt to recover both types of waste heat, but the lack of efficient energy storage methods after recovery leads to the loss of a large amount of valuable heat energy, which cannot be effectively utilized.

[0003] Shipboard equipment such as water makers and heating, ventilation, and air conditioning (HVAC) systems have a continuous demand for heat energy, requiring a stable heating supply to ensure their normal operation. Current technologies often rely on additional fuel consumption or keeping auxiliary boilers running continuously to meet the heating needs of these devices. This undoubtedly increases the ship's operating costs significantly and is inconsistent with the trend of energy conservation in shipbuilding.

[0004] When a ship is berthed, undergoing maintenance, or operating its main engine at low load, the waste heat supply may suddenly be interrupted. In this situation, current technology can only start auxiliary boilers and run them at full load to maintain heating. This method is not only extremely energy-intensive, resulting in serious energy waste, but also has poor heating stability, making it difficult to ensure the normal operation of various heat-requiring equipment on board, thereby affecting the overall operating efficiency of the ship.

[0005] While the prior art document (CN202210837329.8) involves waste heat recovery and thermal storage tank design, this technology uses steam heating coils to indirectly heat the thermal storage medium, which has significant drawbacks. Firstly, the heat exchange efficiency is low, failing to quickly and fully transfer the heat energy of the steam to the thermal storage medium. Secondly, the temperature control of the thermal storage tank is lagging, making it difficult to adjust the temperature within the tank in a timely manner according to actual needs. Furthermore, this technology is not optimized for rapid reheating and constant temperature output after the main engine stops, failing to meet the urgent needs of ships for high efficiency, energy saving, and stable heating under complex operating conditions.

[0006] Therefore, the current field of ship heat energy recovery and utilization urgently needs a ship heat energy recovery system with active constant temperature control, dual waste heat direct supply energy storage, and low-consumption heat replenishment functions to solve the core pain points of existing technologies, such as incomplete waste heat recovery, low energy storage efficiency, and high and unstable heating energy consumption when the main engine is shut down or at low load. Summary of the Invention

[0007] The present invention aims to overcome at least one of the defects of the prior art and provide a ship active heat recovery system and method to overcome the defects of the prior art, such as incomplete recovery of ship waste heat, low energy storage efficiency, and high and unstable heating energy consumption when the main engine is shut down or at low load.

[0008] The ship heat recovery system of this invention comprises four core components: an active constant-temperature energy storage unit, an intelligent auxiliary heating unit, a heat distribution and waste heat recovery unit, and a flue gas waste heat recovery unit. These units are connected via scientific piping to form a complete closed loop. The outlet of the active constant-temperature energy storage unit is flange-connected to the inlet of the intelligent auxiliary heating unit. The active constant-temperature energy storage unit features bidirectional heat exchange, enabling efficient storage and active release of waste heat, thus overcoming the lag in temperature control of existing patented heat storage tanks. The outlet of the intelligent auxiliary heating unit is directly connected to the inlet of the heat distribution and waste heat recovery unit, allowing for on-demand supplementary heating of the hot water output from the active constant-temperature energy storage unit, activating micro-supplementary heating only when the water temperature output from the energy storage unit is below standard. The heat energy distribution and waste heat recovery unit performs the dual functions of hot water terminal distribution and cylinder liner water waste heat recovery. Its outlet is divided into two paths: one connects to the inlet of the flue gas waste heat recovery unit, and the other connects to the inlet of the active constant-temperature energy storage unit after recovering heat energy from the main engine cylinder liner water. The flue gas waste heat recovery unit specifically recovers heat energy from the high-temperature flue gas of the main engine, heats the low-temperature return water, and then transmits it to the active constant-temperature energy storage unit, achieving simultaneous recovery and recycling of both waste heat sources. This overall architecture overcomes the limitations of existing technologies, such as single waste heat recovery paths and poor system coordination. Through the precise division of labor and closed-loop linkage of the four major units, it maximizes the exploitation of ship waste heat resources and ensures minimal heat loss throughout the entire process of recovery, storage, and power supply. This reflects a reconstruction and upgrade of the ship's thermal energy utilization system and possesses outstanding substantive innovation.

[0009] Furthermore, the active constant-temperature energy storage unit of this invention serves as the core of the system. Internally, it comprises an active constant-temperature energy storage chamber, a variable-frequency hot water circulation pump, and a first plate heat exchanger, all connected sequentially via pipelines. The outlet pipe of the first plate heat exchanger connects to both the intelligent auxiliary heating unit and the active constant-temperature energy storage chamber, forming a bidirectional channel for energy storage and supply, enabling bidirectional switching between waste heat storage and active energy release. The unit is also equipped with a first intelligent control box and multiple temperature sensor components. The first intelligent control box establishes a control connection with the variable-frequency hot water circulation pump and the temperature sensor components, receiving real-time data feedback from the temperature sensor components and dynamically controlling the start / stop status of the variable-frequency hot water circulation pump. This, in turn, adjusts the heat exchange efficiency of the first plate heat exchanger, achieving precise dynamic control of the water temperature within the active constant-temperature energy storage chamber. More preferably, the first plate heat exchanger is a plate heat exchanger with a heat exchange efficiency ≥95%, representing a more than 30% improvement in heat exchange efficiency compared to the steam heating coils in existing patents, completely solving the problem of low heat exchange efficiency in existing technologies.

[0010] This invention solves the technical bottlenecks of existing energy storage units, such as lagging temperature control and insufficient adjustment accuracy. The dynamic response capability of the variable frequency hot water circulation pump ensures that the water temperature inside the tank can quickly adapt to changes in the ship's heat load and be maintained within the set range. The bidirectional connection design of the first plate heat exchanger not only ensures efficient storage of waste heat but also realizes orderly output of hot water. Combined with the precise control logic of the first intelligent control box, the active constant temperature energy storage unit has active temperature control capability. Compared with the existing passive energy storage structure, the flexibility and reliability are greatly improved, providing core technical support for the stable operation of the entire system.

[0011] Furthermore, the active constant temperature energy storage chamber, as the core carrier for thermal energy storage, has a composite rock wool insulation layer with a thickness of 90~110mm on its surface. More preferably, the thickness of the composite rock wool insulation layer is 100mm, and the heat loss rate is ≤3% / 24 hours. The active constant temperature energy storage chamber is made of marine stainless steel, and the working pressure is set to 0.3-0.5MPa.

[0012] More preferably, the entire surface of the active thermostatic energy storage tank is covered with a composite rock wool insulation layer. This insulation cotton has the characteristics of low thermal conductivity, anti-aging, and resistance to the harsh marine environment. It can effectively prevent heat loss from the tank to the outside, significantly reduce heat loss, and ensure that the water temperature of the thermostatic energy storage tank is kept constant within the set range of 80-85℃ for a long time. It is a key structure for achieving efficient thermostatic energy storage. Marine-grade stainless steel has excellent corrosion resistance, anti-aging properties, and mechanical strength, and can easily cope with the high humidity, salt spray, and other harsh environments during ship navigation, effectively extending the service life of the active thermostatic energy storage tank and reducing equipment maintenance costs. The 0.3-0.5MPa working pressure design ensures the smooth flow of hot water in the circulation pipeline while ensuring the structural safety of the active thermostatic energy storage tank, eliminating the need for additional high-pressure drive equipment and reducing system energy consumption. The synergistic design of these three components enables the active constant temperature energy storage chamber to possess both excellent structural stability and weather resistance, while also achieving efficient thermal insulation and energy storage. This lays an important foundation for the overall energy saving and stable operation of the system, and allows for comprehensive capture of water temperature changes during the bidirectional heat exchange process, providing precise data support for the first intelligent control box.

[0013] The active thermostatic energy storage unit is also equipped with a complete set of auxiliary components, including a flow regulating valve, a high-level sensor, a low-level sensor, a vacuum vent valve, a normally open valve, a drain valve, a water supply valve, and an isolation valve. The flow regulating valve is installed on the inlet and outlet pipes connecting to the active thermostatic energy storage chamber, which can accurately control the inflow and outflow of water to ensure a balance between energy storage and supply. The high-level and low-level sensors are installed at the top and bottom of the active thermostatic energy storage chamber, respectively, and work in conjunction with the water supply valve and the drain valve for coordinated control.

[0014] A vacuum vent valve is installed on the top of the active constant temperature energy storage chamber. Since the constant temperature energy storage chamber is a hot water chamber, the chamber will generate stable pressure due to the water temperature being maintained at 80-85℃. To ensure pressure balance and constant temperature inside the chamber, the vacuum vent valve is normally closed. When the pressure inside the chamber exceeds the set value, it automatically opens to release the pressure, and when the pressure is lower than the set value, it automatically closes. This ensures the thermal insulation and energy storage effect and structural safety of the active constant temperature energy storage chamber. Combined with the composite rock wool insulation layer W1 covering the outside of the chamber, heat loss is further reduced, providing double protection for the long-term stable storage of thermal energy.

[0015] The water supply valve is located at the top of the active thermostatic energy storage chamber and is used to control the inflow of external water into the active thermostatic energy storage chamber to replenish water; the drain valve is located at the bottom of the active thermostatic energy storage chamber and is used to drain the water in the active thermostatic energy storage chamber; the drain valve and the isolation valve are respectively installed on the connecting pipes of the active thermostatic energy storage chamber to realize the functions of draining and isolation. The temperature sensor assembly includes a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is fixed to the active thermostatic energy storage chamber to monitor the water temperature in real time. The second and third temperature sensors are respectively arranged on the inlet and outlet pipes of the first plate heat exchanger to capture water temperature changes during the heat exchange process from all angles. Therefore, through the linkage connection between the first intelligent control box and the temperature sensor assembly, pressure sensor, and liquid level sensor, the start, stop, and operating power of the variable frequency hot water circulation pump can be automatically controlled based on multiple parameter signals such as temperature, pressure, and liquid level. This achieves dynamic heat exchange between the active thermostatic energy storage chamber and the circulation loop. Combined with the insulation effect of the composite rock wool insulation layer, it ensures that the temperature of the active thermostatic energy storage chamber remains stable within the set range, fully leveraging its core energy storage and regulation functions. This design constructs a complete multi-dimensional safety control and monitoring system, capable of capturing and responding promptly to changes in key parameters such as temperature, water level, and pressure, avoiding equipment failures or safety hazards. It also provides comprehensive data support for the intelligent control box, further improving the accuracy and reliability of system regulation, reflecting the comprehensiveness and rigor of the design.

[0016] The performance parameters of the vacuum vent valve and temperature sensors are precisely defined. The opening pressure of the vacuum vent valve is 0.15 MPa, and the closing pressure is 0.1 MPa. The measurement range of the first, second, and third temperature sensors is 0-100℃, with a measurement accuracy of ±0.5℃, ensuring accurate temperature control and overcoming the lag in existing patented temperature control systems. Reasonable pressure parameter settings enable the active thermostatic energy storage chamber to automatically depressurize when the pressure is too high, preventing structural damage, and to seal and insulate when the pressure is too low, reducing heat loss and achieving the optimal combination of pressure balance and insulation effect. The high-precision temperature sensors can accurately capture minute changes in water temperature, providing reliable data support for the first intelligent control box and ensuring precise adjustment of heat exchange efficiency. This design solves the problem of temperature control lag caused by pressure control imbalance and insufficient temperature measurement accuracy in existing technologies. The precise pressure control of the vacuum vent valve ensures the structural safety and energy storage effect of the active constant temperature energy storage chamber, while the high-precision temperature sensor ensures the timeliness and accuracy of water temperature regulation, avoiding unstable energy supply or energy waste caused by temperature deviation, and further improving the system's operating efficiency and stability.

[0017] The intelligent auxiliary heating unit is used to supplement heating when the output water temperature of the active thermostatic energy storage tank does not meet the requirements, ensuring that the water temperature entering downstream equipment meets the standards. It serves as a supplementary guarantee for the core heat source of the active thermostatic energy storage tank. It includes an intelligent heating controller, an auxiliary heater, a fourth temperature sensor, and a fifth temperature sensor.

[0018] The fourth and fifth temperature sensors are installed on the inlet and outlet pipes of the intelligent auxiliary heating unit, respectively, and are both electrically connected to the intelligent heating controller. They are used to monitor the temperature of the hot water entering the auxiliary heating unit from the active constant-temperature energy storage chamber, and the temperature of the hot water about to enter the heat distribution and waste heat recovery unit after auxiliary heating. The intelligent heating controller can determine whether to start the auxiliary heater based on the inlet water temperature data monitored by the fourth temperature sensor, and simultaneously adjust the heating power of the auxiliary heater based on the outlet water temperature data monitored by the fifth temperature sensor, ensuring that the output hot water temperature downstream meets the standard. This design solves the problems of inaccurate start / stop and unstable heating effect of existing auxiliary heating equipment. The closed-loop monitoring of the dual temperature sensors enables full control of the heating process, avoiding energy waste caused by insufficient or excessive heating. The auxiliary heater only starts when the output water temperature of the active constant-temperature energy storage unit does not meet the standard. Relying on the high-efficiency energy storage of the energy storage unit, it does not require high-load operation. Compared with the existing technology where the auxiliary boiler operates at high load throughout the entire process, this significantly reduces energy consumption while ensuring the water temperature stability of downstream heat-requiring equipment and improving the system's energy supply quality.

[0019] The heat energy distribution and waste heat recovery unit, as the core of heat energy distribution and end-use utilization, connects various heat-requiring equipment on the ship and realizes the circulating heating of warm water. Its circulation loop design revolves around the energy storage and heating needs of the constant-temperature energy storage tank. It includes a dual-pump redundant variable frequency circulating pump set, a multi-functional heat energy distribution terminal, a cylinder liner water direct supply heat exchanger, a second intelligent control box, and a first valve assembly. The dual-pump redundant variable frequency circulating pump set is connected to the multi-functional heat energy distribution terminal, which is connected to the cylinder liner water direct supply heat exchanger. The intelligent control box is connected to the first valve assembly and is used to switch the water flow path according to the water temperature, with a switching response time ≤2s.

[0020] The dual-pump redundant variable frequency circulating pump set, employing a dual-pump redundancy design to ensure operational stability, efficiently transports qualified hot water, regulated by the active constant temperature energy storage tank and supplemented by the intelligent auxiliary heating unit, to the multi-functional heat energy distribution terminal. The dual-pump redundancy design ensures continuous pump operation, preventing power outages due to single-pump failure. The variable frequency function dynamically adjusts the flow rate according to the terminal load, reducing energy consumption. The multi-functional heat energy distribution terminal is compatible with all heat-requiring equipment on board, such as water makers, cabin heating coils, HVAC systems, and heaters. After the hot water releases heat through the terminal equipment, its temperature drops below 60°C, forming low-temperature return water, which is then returned to the active constant temperature energy storage tank for reheating and energy storage. This system solves the problem of limited adaptability in existing systems, eliminating the need for separate designs for different equipment and reducing ship retrofitting costs. The cylinder liner water direct-supply heat exchanger connects to the ship's main engine cylinder liner water system, utilizing the heat energy of the main engine's cylinder liner water (above 90°C) to heat the water discharged from the multi-functional heat energy distribution terminal (below 60°C). This raises the temperature of the circulating water before it is introduced into the active thermostatic energy storage tank, reducing the heating load on the tank. Combined with the insulation effect of thermal insulation cotton, this further improves the overall system's energy utilization efficiency and enables secondary recovery and utilization of waste heat, achieving a heat exchange efficiency of ≥95%. Through component redundancy design, terminal standardization, and intelligent path switching, this unit achieves a dual improvement in heat energy utilization efficiency and system reliability, demonstrating deep optimization and integrated innovation in heat energy distribution and recovery.

[0021] The flue gas waste heat recovery unit is used to recover the high-temperature flue gas heat energy from the main unit's exhaust pipe, converting it into usable heat energy to heat the circulating water, and ultimately supplementing the active constant-temperature energy storage chamber with heat energy. It is one of the important heat energy sources for the active constant-temperature energy storage chamber. It includes an exhaust gas economizer, a dual-pump redundant variable frequency high-temperature water circulation pump set, a high-temperature water heat exchanger, a third intelligent control box, and a second valve assembly.

[0022] The exhaust gas economizer is installed on the main unit's exhaust pipe and can efficiently absorb the heat energy of the 400℃ high-temperature flue gas discharged from the main unit. The dual-pump redundant variable frequency high-temperature water circulation pump set is connected to the exhaust gas economizer and the high-temperature water heat exchanger, forming a closed-loop circulating water system to ensure the recycling of high-temperature water. The absorbed flue gas heat energy is transferred to the low-temperature return water flowing back to the active constant temperature energy storage chamber, reducing heat loss and achieving efficient recovery and transfer of flue gas waste heat. The third intelligent control box is connected to the dual-pump redundant variable frequency high-temperature water circulation pump set and temperature sensors to control the operating status of the pump set. This invention's exhaust gas economizer is directly installed in the exhaust pipe to maximize the capture of flue gas heat energy. The closed-loop system reduces heat loss during transfer, and the dual-pump redundancy design ensures stable operation of the circulation system. The third intelligent control box (E4) is electrically connected to the dual-pump redundant variable frequency high-temperature water circulation pump set (E2) and the waste heat recovery temperature sensor to control the pump set's operating status, ensuring the high-temperature water temperature remains stable at around 120℃, achieving dual-path synergistic recovery with cylinder liner water waste heat. Overall, it achieves efficient conversion of flue gas heat energy into usable heat energy, providing a stable heat source for low-temperature return water heating, and forming a dual-path synergy with cylinder liner water waste heat recovery. This overcomes the technical bottlenecks of low efficiency and insufficient utilization in traditional flue gas waste heat recovery, realizing the comprehensive exploitation of ship waste heat resources.

[0023] Based on the aforementioned ship heat recovery system, this invention also discloses a corresponding ship heat recovery method, which includes a heat recovery process during normal engine operation and a heat supply process when the engine is stopped. During normal engine operation, the active constant-temperature energy storage unit is first activated. The variable-frequency hot water circulation pump starts according to the initial cabin temperature monitored by the first temperature sensor, and adjusts the cabin water temperature through the first plate heat exchanger to stabilize the cabin temperature at a first threshold. Subsequently, the hot water enters the intelligent auxiliary heating unit. The fourth and fifth temperature sensors monitor the water temperature. If the water temperature is lower than the first threshold, the auxiliary heater is activated to heat it to the first threshold; otherwise, the hot water flows directly into the heat distribution and waste heat recovery unit. The hot water is then transported to multiple units via a dual-pump redundant variable-frequency circulation pump group. The functional heat energy distribution terminal supplies energy to the heat-requiring equipment and then forms low-temperature return water. After being heated by the cylinder liner water direct supply heat exchanger, the low-temperature return water is switched by the intelligent control box according to the water temperature. When the water temperature is lower than the second threshold, it flows into the high-temperature water heat exchanger for further heating and then flows back to the active constant temperature energy storage chamber. When the water temperature is not lower than the second threshold, it flows directly back to the active constant temperature energy storage chamber. During this process, the flue gas waste heat recovery unit operates synchronously. The waste gas economizer absorbs the heat energy of the main unit's flue gas, heats the circulating water, and then heats the low-temperature return water through the high-temperature water heat exchanger.

[0024] When the main unit stops operating, the flue gas waste heat recovery unit and the cylinder liner water direct supply heat exchanger stop working. The active constant temperature energy storage chamber maintains the temperature of the third threshold under the action of the insulation layer. The second intelligent control box of the heat energy distribution and waste heat recovery unit switches the valve, and the low temperature return water flows directly into the active constant temperature energy storage unit. The active constant temperature energy storage unit starts the reverse heat exchange function to heat the low temperature return water to the fourth threshold. The hot water enters the intelligent auxiliary heating unit, and after the auxiliary heater slightly heats it to the second threshold, it is delivered to the multi-functional heat energy distribution terminal to supply energy to the equipment that needs heat.

[0025] The method of this invention innovatively realizes adaptive energy supply under all operating conditions. When the main engine is running normally, it maximizes the recovery of dual waste heat. After the main engine stops, it relies on energy storage in the energy storage compartment and auxiliary micro-heating to replace the traditional high-energy-consuming energy supply mode. It solves the contradiction between the continuity and energy saving of heat energy supply under different operating conditions of the ship, and reflects the systematicness and innovation of the method.

[0026] The temperature ranges of the first, second, third, and fourth thresholds of this invention have been verified and determined. The temperature range of the first threshold is 80~85℃, the second threshold is 83~88℃, the third threshold is 78~88℃, and the fourth threshold is 68~72℃. The reasonable threshold range settings match the optimal operating temperature of the ship's heat-requiring equipment while also considering the system's heat exchange efficiency and energy-saving requirements, avoiding unstable energy supply or energy waste caused by unreasonable threshold settings. The first threshold ensures that the active constant-temperature energy storage compartment stores sufficient compliant heat energy; the second threshold ensures the quality of terminal energy supply; the third threshold reflects the excellent insulation performance of the energy storage compartment; and the fourth threshold provides a reasonable transition for the connection between reverse heat exchange and auxiliary heating. The quantified temperature thresholds make system control more operable and precise, ensuring orderly connection and stable operation of each process, further improving the system's reliability and energy-saving effect. The aforementioned threshold range has been verified and determined under multiple operating conditions. It not only matches the optimal operating temperature of the ship's heat-requiring equipment, but also takes into account the system's heat exchange efficiency and energy-saving requirements. This avoids the unstable energy supply or energy waste caused by unreasonable threshold settings in existing patents. At the same time, it is combined with active constant temperature control to ensure that each process is connected in an orderly manner and operates stably.

[0027] This invention combines a dual waste heat direct supply path (cylinder liner water / flue gas waste heat directly heating circulating water) with a plate heat exchanger (efficiency ≥95%), and uses a first intelligent control box (S4) to collect data from three temperature sensors (T101 / T102 / T103) in real time, dynamically adjusting the speed of the variable frequency pump (response time ≤1s) to achieve precise temperature control of the heat storage chamber (±0.5℃), completely solving the problems of inefficient heat exchange and temperature control lag in the original patent.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention integrates heat energy recovery and storage, and doubles the recovery efficiency: the heat energy of the main unit cylinder liner is recovered through the high temperature water heat exchanger of the main unit, and the heat energy of the exhaust gas is recovered through the exhaust gas economizer. All the recovered heat energy is stably stored in the active constant temperature energy storage chamber as the core carrier. Combined with the low loss insulation design of the composite rock wool insulation layer, the problem of heat energy recovery cannot be retained is avoided, and the two main waste heats of the main unit are fully recovered and efficiently retained, greatly reducing energy waste.

[0029] (2) Extreme improvement in energy utilization: The composite rock wool insulation layer of the active constant temperature energy storage chamber has excellent thermal insulation performance, ensuring that the recovered heat energy can be retained stably for a long time, and the stored heat energy can be directly used for heating of ship heat-requiring equipment, reducing intermediate losses. Compared with existing technologies, the overall energy utilization efficiency is improved by more than 40%.

[0030] (3) Significantly reduced operating costs: When the main engine is running normally, the waste heat stored and recovered by the active constant temperature energy storage tank is kept constant under the action of the composite rock wool insulation layer, without the need for additional energy consumption to heat the equipment; when the main engine stops running, the energy stored in the active constant temperature energy storage tank is the main heat source, and the auxiliary boiler only needs to be slightly heated to meet the heating demand, which replaces the mode of the auxiliary boiler running at high load throughout the process in the existing technology. Actual verification shows that fuel consumption is reduced by more than 60%, significantly reducing the ship's operating costs.

[0031] (4) Industry-leading heating stability: The active constant temperature energy storage tank has a constant temperature design of 80-85℃ and low-loss insulation characteristics of composite rock wool insulation layer. Combined with the multiple designs of heat energy circulation loop and auxiliary boiler supplementary heating, it can provide stable hot water of about 85℃ for ship heating equipment regardless of whether the main engine is running. This completely solves the problem of heating interruption or instability when the main engine stops running in the existing technology, ensuring normal operation of equipment.

[0032] (5) Wide adaptability and safe and reliable: The multi-functional heat energy distribution terminal can be adapted to various ship heat-requiring equipment such as water makers, cabin heating coils, HVAC, and warm air blowers; at the same time, the active constant temperature energy storage tank is equipped with a complete set of safety control components such as temperature sensors, liquid level switches, and vacuum vent valves. Combined with the environmental resistance characteristics of the composite rock wool insulation layer, it realizes all-round monitoring of temperature, liquid level, and pressure and structural protection, ensuring the long-term safe and stable operation of the system.

[0033] (6) The combined advantages of active constant temperature energy storage tank and thermal insulation cotton are highlighted: the active constant temperature energy storage tank is the energy core and operation hub of the whole system, and the composite rock wool insulation layer is the key guarantee for achieving efficient constant temperature energy storage. The two work together to connect the entire process of heat energy recovery, storage, regulation and supply. When the main engine is running, it is a "high-efficiency storage warehouse" for waste heat, and when the main engine stops, it is a stable "low-loss energy source". Its combined design makes heat energy recycling and low-consumption heating possible, and completely solves the core pain point in the field of existing ship heat energy utilization. Attached Figure Description

[0034] Figure 1 This is a schematic diagram illustrating the connection principle of the ship heat recovery system of the present invention.

[0035] Figure 2 This is a schematic diagram of the active constant temperature energy storage unit and the intelligent auxiliary heating unit of the ship heat energy recovery system of the present invention. Detailed Implementation

[0036] The accompanying drawings illustrate the technical solutions of the embodiments of the present invention in more detail. Throughout the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The described embodiments are some, but not all, embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0038] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0039] Example

[0040] I. Structure of Each Component of a Ship's Active Heat Recovery System 1. Active Constant Temperature Energy Storage Unit 100: This unit is responsible for direct waste heat storage, active constant temperature control, and safe output. Its core component is the active constant temperature energy storage chamber S3, which is equipped with a first intelligent control box and insulation structure. It is made of marine-grade stainless steel, and its volume is determined based on the total heat load of the ship's heat-requiring equipment. In this embodiment, a volume of 50 m³ is selected, with a design temperature of 80-85℃ and an operating pressure of 0.3 MPa. The outer surface of the chamber is covered with a 100 mm thick composite rock wool insulation layer W1. Testing showed a 24-hour heat loss rate of 2.8%, meeting the design requirements. 2. Variable Frequency Hot Water Circulation Pump S1: This pump uses a stainless steel impeller, with a rated flow rate of 50 m³ / h, a rated head of 30 m, a power of 7.5 kW, and a frequency conversion range of 30-50 Hz. It can dynamically adjust the speed according to the water temperature signal to achieve precise flow control. The first plate heat exchanger S2 has a heat exchange area of ​​20 m², with plates made of 316L stainless steel, a design pressure of 1.0 MPa, a design temperature of 150℃, and a heat exchange efficiency of ≥95%. The active constant temperature energy storage chamber S3 has a set temperature range of 80-85℃. When the first temperature sensor T101 detects that the water temperature is below 80℃, the first intelligent control box controls the variable frequency hot water circulation pump S1 to increase its speed and increase the heat exchange volume; when the water temperature is above 85℃, the speed of the variable frequency hot water circulation pump S1 is reduced to decrease the heat exchange volume.

[0041] Valve assembly: first flow regulating valve V101, second flow regulating valve V102, first normally open valve V103, second normally open valve V104, third normally open valve V105, isolation valve V106, vent valve V107, and water supply valve V108; wherein the first flow regulating valve V101 and the second flow regulating valve V102 can precisely control the water flow into and out of the energy storage compartment; the first normally open valve V103 and the second normally open valve V104 are arranged at the inlet end of the heat exchanger to control the water flow in separate circuits, and the third normally open valve V105 is arranged at the outlet end of the heat exchanger.

[0042] Temperature sensor assembly: First temperature sensor T101, second temperature sensor T102, and third temperature sensor T103; T101 is fixed on the active constant temperature energy storage chamber S3, monitoring the water temperature inside the chamber in real time to ensure that the water storage chamber temperature is stably maintained within the set range of 80-85℃, providing a stable heat source foundation for the system, and is the core sensing component for the active constant temperature energy storage chamber S3 to achieve precise temperature control; Second temperature sensor T102 is arranged on the inlet pipe of the first plate heat exchanger S2, monitoring the water temperature entering the heat exchanger, providing data support for the heat exchange regulation of the active constant temperature energy storage chamber S3; Third temperature sensor T103 is arranged on the outlet pipe of the first plate heat exchanger S2, monitoring the water temperature after being treated by the heat exchanger, ensuring that the water temperature entering or flowing out of the active constant temperature energy storage chamber S3 meets the circulation requirements.

[0043] Liquid level switch assembly: High liquid level sensor LS001 and low liquid level sensor LS002 are respectively the high-level alarm liquid level switch and the low-level anti-pump dry-run alarm switch of the active constant temperature energy storage tank S3. If the water level of the active constant temperature energy storage tank S3 is too high, the high-level alarm switch of the high liquid level sensor LS001 is triggered, stopping the water injection into the active constant temperature energy storage tank S3 and closing the water supply valve V108. If the water level of the active constant temperature energy storage tank S3 is too low, the low-level alarm switch of the low liquid level sensor LS002 is triggered, opening the water supply valve V108 to inject water into the active constant temperature energy storage tank S3, preventing the variable frequency hot water circulation pump S1 from running dry and burning out the motor, and ensuring the safe and stable operation of the active constant temperature energy storage tank S3.

[0044] Pressure sensor PT101 is installed on the active thermostatic energy storage chamber S3 to monitor pressure changes inside the chamber. A vacuum vent valve PV01 is installed on the top of the active thermostatic energy storage chamber S3. Since the active thermostatic energy storage chamber S3 is a hot water chamber, a stable pressure is generated inside the chamber due to the water temperature being maintained at 80-85℃. To ensure pressure balance and constant temperature inside the chamber, the vacuum vent valve is normally closed. When the pressure inside the chamber exceeds the set value, it automatically opens to release the pressure; when the pressure falls below the set value, it automatically closes. This ensures the thermal insulation and energy storage effect and structural safety of the active thermostatic energy storage chamber S3. Combined with the composite rock wool insulation layer W1 covering the outside of the chamber, heat loss is further reduced, providing double protection for the long-term stable storage of thermal energy. This insulation material has the characteristics of low thermal conductivity, anti-aging, and resistance to harsh marine environments. It can effectively block the heat energy inside the tank from being dissipated to the outside, significantly reduce heat loss, and ensure that the water temperature of the active constant temperature energy storage tank S3 is kept constant within the set range of 80-85℃ for a long time. It is a key structure for achieving efficient thermal insulation energy storage.

[0045] Control module: The first intelligent control box S4 is connected to the first temperature sensor T101, the second temperature sensor T102, and the third temperature sensor T103. It can automatically control the start, stop, and operating power of the variable frequency hot water circulation pump S1 based on the temperature signals transmitted by the first temperature sensor T101, the second temperature sensor T102, and the third temperature sensor T103. This enables dynamic heat exchange between the active constant temperature energy storage chamber S3 and the circulation loop. Combined with the insulation effect of the composite rock wool insulation layer W1, it ensures that the temperature of the active constant temperature energy storage chamber S3 remains stable within the set range, fully leveraging its core energy storage and regulation functions.

[0046] 2. Intelligent auxiliary heating unit 200 The intelligent auxiliary heating unit 200 is used to supplement heating when the output water temperature of the active constant temperature energy storage chamber S3 does not meet the requirements, ensuring that the water temperature entering downstream equipment meets the standards. It is a supplementary guarantee for the core heat source of the active constant temperature energy storage chamber S3, and specifically includes: Temperature sensors: fourth temperature sensor G101 and fifth temperature sensor G102; the fourth temperature sensor G101 is arranged on the inlet pipe of the intelligent auxiliary heating unit 200 to monitor the temperature of the hot water entering the auxiliary heating unit from the active constant temperature energy storage unit 100; the fifth temperature sensor G102 is arranged on the outlet pipe to monitor the temperature of the hot water that is about to enter the heat energy distribution and waste heat recovery unit 300 after auxiliary heating.

[0047] Heating equipment: Auxiliary heater F1, which adopts electric heating method, rated power of 30kW, heating tube material is Incoloy800, starting current ≤1.2 times rated current, has low energy consumption start-up characteristics, and only starts when the output water temperature of the active constant temperature energy storage chamber S3 is insufficient. Relying on the energy storage foundation of the active constant temperature energy storage chamber S3 and the heat preservation effect of the composite rock wool insulation layer W1, it does not require high load operation.

[0048] Control module: Intelligent heating controller F2, which is electrically connected to the fourth temperature sensor G101 and the fifth temperature sensor G102, is used to control the start-up, stop and heating power of the auxiliary heater F1.

[0049] Valve assembly: first normally open shut-off valve VH1, second normally open shut-off valve VH2, electric switching valve VH3; the first normally open shut-off valve VH1 and the second normally open shut-off valve VH2 are used to maintain the normal water flow channel, and the electric switching valve VH3 is controlled by the intelligent heating controller F2 to realize the switching of the heating circuit.

[0050] 3. Heat distribution and waste heat recovery unit 300 The heat distribution and waste heat recovery unit 300 serves as the core for heat distribution and end-use utilization, connecting various heat-requiring equipment on the ship and realizing the circulating heating of warm water. Its circulation loop design revolves around the energy storage and heating needs of the active constant-temperature energy storage compartment S3, specifically including: Delivery equipment: Dual-pump redundant variable frequency circulating pump set R1 (adopting a dual-pump redundancy design to ensure operational stability), used to efficiently transport qualified hot water regulated by the active constant temperature energy storage chamber S3 and supplemented by the intelligent auxiliary heating unit 200 to the multi-functional heat energy distribution terminal. The dual-pump redundant variable frequency circulating pump set R1 has two pumps that serve as backups for each other. Each pump has a rated flow rate of 80 m³ / h, a rated head of 40 m, a power of 15 kW, a frequency conversion range of 30-50 Hz, and is equipped with an automatic switching control module to ensure operational reliability.

[0051] Terminal equipment: The multi-functional heat distribution terminal R2 can be adapted to all heat-requiring equipment on the ship, such as water makers, cabin heating coils, HVAC, and heaters. After hot water flows through the terminal equipment and releases heat, the water temperature drops to below 60°C, forming low-temperature return water, which is prepared for subsequent return to the active constant temperature energy storage tank S3 for reheating and energy storage.

[0052] Valve assembly: Fourth normally open valve VR1, fifth normally open valve VR2, sixth normally open valve VE1, seventh normally open valve VE2, eighth normally open valve VG1, ninth normally open valve VG2, first control valve R201, second control valve R202, third control valve R203, and fourth control valve R204, used to switch water flow paths to ensure that low-temperature return water can flow back to the active constant temperature energy storage chamber S3 or related heat exchangers for heating as needed.

[0053] Heating Supplement Module: The cylinder liner water direct supply heat exchanger R3 is connected to the ship's main engine cylinder liner water system. It can utilize the heat energy of the main engine's cylinder liner water (above 90°C) to heat the water discharged from the multi-functional heat energy distribution terminal R2 (below 60°C). After raising the temperature of the circulating water, it is then introduced into the active constant temperature energy storage tank S3, reducing the heating load of the active constant temperature energy storage tank S3. Combined with the heat insulation effect of W1 insulation cotton, it further improves the energy utilization efficiency of the entire system.

[0054] Control module: The second intelligent control box R4 for heat energy distribution and waste heat recovery is connected to the first control valve R201, the second control valve R202, the third control valve R203, the fourth control valve R204 and the sixth temperature sensor T201. It is used to control these electric switching valves to realize the switching between heat energy distribution and waste heat recovery.

[0055] 4. Flue gas waste heat recovery unit 400 The flue gas waste heat recovery unit 400 is used to recover the high-temperature flue gas heat energy from the main unit's exhaust pipe, converting it into usable heat energy to heat the circulating water, ultimately supplementing the heat energy for the active constant-temperature energy storage chamber S3. It is one of the important heat energy sources for the active constant-temperature energy storage chamber S3, specifically including: Flue gas heat recovery equipment: E1 exhaust gas economizer, installed on the exhaust pipe of the ship's main engine, can efficiently absorb the heat energy of the high-temperature flue gas of about 400℃ discharged from the main engine. The E1 exhaust gas economizer adopts a finned structure, with a heat exchange area of ​​100m², a design temperature of 500℃, an operating pressure of 1.0MPa, and a flue gas resistance ≤500Pa.

[0056] Circulation System: The dual-pump redundant variable frequency high-temperature water circulation pump set E2, together with the exhaust gas economizer E1 and the high-temperature water heat exchanger E3, forms a closed-loop circulating water system. This ensures the recycling of high-temperature water, transferring the absorbed flue gas heat energy to the low-temperature return water flowing back to the active constant temperature energy storage chamber S3. Each pump in the dual-pump redundant variable frequency high-temperature water circulation pump set E2 has a rated flow rate of 60 m³ / h, a rated head of 50 m, a power of 11 kW, and a frequency conversion range of 30-50 Hz, suitable for the circulation and transportation of high-temperature water.

[0057] Valve assembly: Six normally open valves, namely the tenth normally open valve VF01, the eleventh normally open valve VF02, the twelfth normally open valve VF03, the thirteenth normally open valve VF04, the fourteenth normally open valve VF05, and the fifteenth normally open valve VF06, are arranged on the inlet and outlet pipes of each piece of equipment to maintain the normal water flow channel of the closed circulation system and ensure the stable transfer of flue gas heat energy to the active constant temperature energy storage chamber S3. The waste heat recovery temperature sensors include the seventh temperature sensor T202 and the eighth temperature sensor T203, which are installed at the high temperature water inlet and outlet of the waste gas economizer E1, respectively, to monitor the water temperature at the inlet and outlet.

[0058] Control module: The third intelligent control box E4 for flue gas waste heat recovery is connected to the dual-pump redundant variable frequency high-temperature water circulation pump group E2 and the seventh temperature sensor T202 and the eighth temperature sensor T203. It can automatically control the start, stop and operating power of the dual-pump redundant variable frequency high-temperature water circulation pump group E2 according to the temperature signals transmitted by the seventh temperature sensor T202 and the eighth temperature sensor T203, so as to realize dynamic heat exchange between the active constant temperature energy storage chamber S3 and the circulation loop.

[0059] System connection relationship The outlet pipe of the active constant temperature energy storage unit 100 is connected to the inlet pipe of the intelligent auxiliary heating unit 200 via a flange, realizing the step-by-step transmission of hot water output from the active constant temperature energy storage chamber S3; the outlet pipe of the intelligent auxiliary heating unit 200 is connected to the inlet pipe of the heat energy distribution and waste heat recovery unit 300, and the hot water after auxiliary heating enters the heat energy distribution unit to supply energy to the terminal equipment; the outlet pipe of the heat energy distribution and waste heat recovery unit 300 is divided into two paths: one path is connected to the inlet of the cylinder liner water direct supply heat exchanger R3, and the other path is connected to the inlet of the high-temperature water heat exchanger E3 of the flue gas waste heat recovery unit 400, ensuring that the low-temperature return water can pass through. After being heated through different paths, the water flows back; the outlets of the cylinder liner water direct supply heat exchanger R3 high-temperature water heat exchanger and the high-temperature water heat exchanger E3 are both connected to the inlet pipe of the active constant temperature energy storage unit 100, forming a complete thermal energy circulation loop with the active constant temperature energy storage chamber S3 as the core, so that the heated hot water flows back into the active constant temperature energy storage chamber S3 for storage and reuse; the outlet of the dual-pump redundant variable frequency high-temperature water circulation pump group E2 of the flue gas waste heat recovery unit 400 is connected to the inlet of the high-temperature water heat exchanger E3 to realize the circulation of high-temperature water, provide thermal energy support for the heating of low-temperature return water, and ultimately serve the energy storage needs of the active constant temperature energy storage chamber S3.

[0060] II. System Installation and Debugging During installation, all pipelines are connected using flanges, and high-temperature and high-pressure resistant graphite gaskets are selected for sealing. The pipeline slope is 3‰ to facilitate drainage and venting. The installation positions of detection elements such as temperature sensors, pressure sensors, and level switches should avoid pipe bends, valves, and other local resistance components to ensure the accuracy of the detection data. After system installation, a hydrostatic test is conducted at 1.5 times the design pressure for 30 minutes; no leakage is considered acceptable. Hot-state commissioning is then performed by starting the ship's main engine to bring the system into normal operation. Operating parameters and indicators such as temperature and pressure of each device are monitored, and control parameters are adjusted to ensure stable system operation and compliance with design requirements.

[0061] III. Methods for recovering heat energy from ships

[0062] T1: The active thermostatic energy storage unit 100 starts operation. The hot water circulation pump control box automatically starts the variable frequency hot water circulation pump S1 based on the initial temperature of the active thermostatic energy storage chamber S3 monitored by the first temperature sensor T101. At this time, the first flow regulating valve V101, the second flow regulating valve V102, the first normally open valve V103, the second normally open valve V104, and the third normally open valve V105 are all normally open, and the isolation valve V106 is normally closed. The second temperature sensor T102 monitors the water temperature entering the first plate heat exchanger S2 (initially, it is usually the temperature of the return water in the circulation loop). The system collects warm water, and through the heat exchange of the first plate heat exchanger S2, it regulates the water temperature in the active constant temperature energy storage chamber S3. Combined with the insulation effect of the composite rock wool insulation layer W1, the temperature of the active constant temperature energy storage chamber S3 is stably maintained at around 83℃ (core energy storage temperature). In the initial stage, the outlet temperature of the first plate heat exchanger S2 monitored by the third temperature sensor T103 is below 80℃. As the variable frequency hot water circulation pump S1 continues to circulate and exchange heat, the outlet temperature gradually becomes consistent with the inlet temperature, and finally stabilizes at around 83℃, ensuring that the active constant temperature energy storage chamber S3 stores sufficient heat energy at the required temperature.

[0063] T2: Hot water regulated by the active constant-temperature energy storage unit 100 enters the intelligent auxiliary heating unit 200. The fourth temperature sensor G101 monitors the water temperature in real time. If the fourth temperature sensor G101 detects a water temperature below 83℃, the intelligent heating controller F2 automatically starts the auxiliary heater F1 and simultaneously closes the electric switching valve VH3, heating the hot water to 83℃ through the auxiliary heater. If the fourth temperature sensor G101 detects a water temperature not lower than 83℃, the auxiliary heater F1 remains closed, and the intelligent heating controller F2 opens the electric switching valve VH3, allowing the hot water to flow directly to the heat energy distribution and waste heat recovery unit 300. The fifth temperature sensor G102 monitors the water temperature entering the heat energy distribution and waste heat recovery unit 300 in real time, ensuring that the water temperature meets the requirements of the terminal equipment. During this process, the composite rock wool insulation layer of the active constant-temperature energy storage chamber continuously plays a role in insulation, maintaining the stability of the core heat source temperature. The fifth temperature sensor G102 detects an outlet water temperature deviation of ≤±0.5℃.

[0064] T3: After the hot water enters the heat energy distribution and waste heat recovery unit 300, the dual-pump redundant variable frequency circulating pump group R1 starts and transfers the hot water to the multi-functional heat energy distribution terminal R2 through the fourth normally open valve VR1 to supply energy to heat-requiring equipment such as water makers and cabin heating coils; after the hot water releases heat in the terminal equipment, it flows out through the fifth normally open valve VR2. At this time, the water temperature drops to below 60℃, forming low-temperature return water.

[0065] T4: The warm water below 60℃ discharged from the heat energy distribution and waste heat recovery unit 300 is continuously heated by the multi-functional heat energy distribution terminal R2 using the cylinder liner water heat energy above 90℃ from the main unit, thus increasing the circulating water temperature. The second intelligent control box of the multi-functional heat energy distribution terminal R2 switches the water flow path based on the monitoring data of the sixth temperature sensor T201 (located on the outlet pipe of the heat energy distribution and waste heat recovery unit 300): if the sixth temperature sensor T201 detects that the water temperature is below 85℃, it controls the first control valve R201 and the second control valve R202 to open, and the fourth control valve R204 to close, allowing the warm water to flow into the high-temperature water heat exchanger E. 3. The flue gas heat energy recovered by the flue gas waste heat recovery unit 400 is heated to about 85°C, and then introduced into the inlet of the active constant temperature energy storage unit 100 and flows into the active constant temperature energy storage chamber S3 for storage, completing the heat energy circulation replenishment; if the sixth temperature sensor T201 detects that the water temperature is not lower than 85°C, the first control valve R201 and the second control valve R202 are closed, and the fourth control valve R204 is opened. The warm water is directly introduced into the inlet of the active constant temperature energy storage unit 100 and flows into the active constant temperature energy storage chamber S3 for internal circulation regulation. Under the action of the heat insulation cotton in S1, the temperature of the water storage chamber is kept stable. The switching response time of all valves is ≤2s.

[0066] T5: The flue gas waste heat recovery unit 400 operates synchronously. The specific process is as follows: When the high-temperature flue gas of about 400°C generated by the main generator set R5 passes through the exhaust pipe, the waste gas economizer E1 absorbs the heat energy of the flue gas, raising the temperature of the circulating water in the closed-loop system to about 120°C. The dual-pump redundant variable frequency high-temperature water circulation pump set E2 transports the 120°C high-temperature water to the high-temperature water heat exchanger E3, which heats the warm water discharged from the waste heat recovery unit 300 for heat energy distribution, and finally converts the heat energy of the flue gas into the stored heat energy of the active constant temperature energy storage chamber S3. The tenth normally open valve VF01, the eleventh normally open valve VF02, the twelfth normally open valve VF03, the thirteenth normally open valve VF04, the fourteenth normally open valve VF05, and the fifteenth normally open valve VF06 of the flue gas waste heat recovery unit 400 are all in the open state to maintain the normal operation of each circulation system and ensure the replenishment of heat energy to the active constant temperature energy storage chamber S3. When the seventh temperature sensor T202 detects that the inlet water temperature of the exhaust gas economizer E1 is below 100℃, the third intelligent control box E4 controls the dual-pump redundant variable frequency high-temperature water circulation pump group E2 to increase the speed; when the eighth temperature sensor T203 detects that the outlet water temperature is above 130℃, the pump group speed is reduced to ensure that the high-temperature water temperature is stable at around 120℃.

[0067] IV. Thermal energy supply process when the main unit is not in operation: Core heating stage of the active constant temperature energy storage compartment S3 T11: After the main generator set R5 stops running, the closed-loop system of the flue gas waste heat recovery unit 400 loses its source of flue gas heat energy and automatically shuts down completely; the multi-functional heat energy distribution terminal R2 also stops heating due to the lack of cylinder liner water heat energy supply. At this time, the active constant temperature energy storage chamber S3 can still maintain a stable temperature of 80-85℃ under the insulation effect of the composite rock wool insulation layer W1, becoming the only core heat source of the system.

[0068] T12: The second intelligent control box R4 of the heat energy distribution and waste heat recovery unit 300 controls the first control valve R201, the second control valve R202, and the fourth control valve R204 to close, and opens the third control valve R203. The warm water discharged from the heat energy distribution and waste heat recovery unit 300 flows directly into the inlet pipe of the active constant temperature energy storage unit 100, preparing to enter the active constant temperature energy storage chamber S3 for heating.

[0069] T13: The second temperature sensor T102 of the active constant temperature energy storage unit 100 detects that the water temperature entering the first plate heat exchanger S2 is below 60°C. The first intelligent control box S4 activates the reverse heat exchange function of the active constant temperature energy storage chamber S3. That is, the active constant temperature energy storage chamber S3 releases heat energy as a heat source. Using the 83°C heat energy stably maintained in the active constant temperature energy storage chamber S3, the low-temperature water is heated through the first plate heat exchanger S2, so that the water temperature at the heat exchanger outlet monitored by the third temperature sensor T103 rises to 70°C. This process fully demonstrates the core heating function of the active constant temperature energy storage chamber S3, and the initial temperature rise can be achieved without relying on an external heat source.

[0070] T14: 70℃ hot water enters the intelligent auxiliary heating unit 200. The fourth temperature sensor G101 detects that the water temperature is below 83℃. The intelligent heating controller F2 starts the auxiliary heater F1 for micro-heating. Only a small amount of heat needs to be added to raise the water temperature to 85℃. Compared with the existing patented auxiliary boiler operating at full load, fuel consumption is reduced by more than 60%.

[0071] T15: 85℃ hot water is introduced into the multi-functional heat energy distribution terminal R2 of the heat energy distribution and waste heat recovery unit 300 to continuously supply energy to the ship's heat-requiring equipment, achieving stable heating when the main engine stops running. Throughout the process, the active constant temperature energy storage chamber S3 is the core foundation of heat energy supply. Its composite rock wool insulation layer W1 effectively reduces heat energy loss, and the auxiliary heater F1 plays a supplementary role, solving the problems of unstable heating and high energy consumption after the main engine stops in the existing patent.

[0072] V. Verification of Operational Results In this embodiment, the ship's main engine power is 5000kW. During normal operation, the cylinder liner water temperature is 95℃ and the flue gas temperature is 400℃. After the system is in operation, the waste heat from the cylinder liner water is recovered through the multi-functional heat energy distribution terminal R2, and the waste heat from the flue gas is recovered through the exhaust gas economizer E1. The test results show that the total recovery efficiency of the two types of waste heat reaches more than 85%.

[0073] When the main engine is running normally, the water temperature in the active constant temperature energy storage tank S3 is stable at around 83°C. The water supply temperature for the ship's heat-requiring equipment is 83°C, which meets the equipment's operating requirements. At this time, the auxiliary heater F1 is not started, and there is no additional energy consumption.

[0074] When the main unit stops operating, the active constant-temperature energy storage chamber S3, thanks to the composite rock wool insulation layer W1, maintains a water temperature above 80°C, with a drop of only 2.5°C within 24 hours. Once the auxiliary heater F1 is activated, it only takes 10 minutes to raise the water temperature to 85°C, continuously supplying energy to heat-requiring equipment. Compared to the existing technology where the auxiliary boiler operates at full load, fuel consumption is reduced by 65%, resulting in significant energy savings.

[0075] In embodiments of this invention, precise constant-temperature energy storage at 80-85℃ is achieved, with a 24-hour heat loss rate of only 2.8%. Waste heat from cylinder liner water and flue gas is directly recovered through a dedicated unit, with cylinder liner water waste heat recovery efficiency ≥90%, flue gas waste heat recovery efficiency ≥85%, and dual-path collaborative recovery efficiency ≥88%. When the main engine is shut down / under low load, energy release from the energy storage compartment and auxiliary heating are linked, resulting in auxiliary heating oil consumption ≤5kg / h, replacing the high-load operation of the auxiliary boiler. This invention solves the pain points of incomplete waste heat recovery, low energy storage efficiency, and unstable heating in existing technologies, reducing fuel consumption by more than 66.7%, saving approximately 182.5 tons of fuel annually, and reducing annual operating costs by approximately 1.46 million yuan. It is suitable for various heat-requiring equipment on ships, significantly improving ship energy utilization efficiency and operational economy. Specific tests are as follows: Table 1. Quantitative data on core temperature stability

[0076] Table 2 Temperature stability under different operating conditions

[0077] Temperature stability guarantee mechanism description Active temperature control linkage: The first intelligent control box S4 receives signals from three sets of temperature sensors. When the temperature inside the cabin deviates from the target value by 0.2℃, it immediately adjusts the speed of the variable frequency hot water circulation pump S1 and quickly replenishes or reduces heat through the dual-flow plate heat exchanger, with a response time of ≤1s.

[0078] Low-loss insulation design: The composite rock wool insulation layer W1 adopts the laying structure shown in the figure. Combined with the chamber sealing design and the pressure balance function of the vacuum vent valve, it blocks the heat conduction and heat convection paths, ensuring that the heat loss rate is stable at ≤3% under different working conditions.

[0079] Adaptive adjustment under operating conditions: The system presets adaptive control strategies for different scenarios such as changes in main engine load, extreme environments, and sudden demands. For example, it can store thermal energy in advance when the main engine is under low load, and appropriately increase the target temperature to 84°C when the ship is sailing in extremely low temperature sea areas to ensure that the temperature stability is not affected by external conditions.

[0080] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the preferred embodiments above, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention should not depart from the spirit and scope of the present invention. Those skilled in the art can also make other changes within the spirit of the present invention and use them in the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made according to the spirit of the present invention should all be included within the scope of protection claimed by the present invention.

Claims

1. A shipboard active heat recovery system, characterized in that, It includes an active constant temperature energy storage unit (100), an intelligent auxiliary heating unit (200), a heat energy distribution and waste heat recovery unit (300), and a flue gas waste heat recovery unit (400). The outlet of the active constant temperature energy storage unit (100) is connected to the inlet of the intelligent auxiliary heating unit (200) via a flange; The outlet of the intelligent auxiliary heating unit (200) is connected to the inlet of the heat distribution and waste heat recovery unit (300); it is used to assist in heating the hot water output by the active constant temperature energy storage unit (100). The heat energy distribution and waste heat recovery unit (300) is used to distribute and utilize hot water at the terminal to form low-temperature return water; the outlet of the heat energy distribution and waste heat recovery unit (300) is divided into two paths, one path is connected to the inlet of the flue gas waste heat recovery unit (400), and the other path is connected to the inlet of the active constant temperature energy storage unit (100) after directly recovering the heat energy of the main engine cylinder liner water, so as to realize the direct supply and recovery of cylinder liner water waste heat; The outlet of the flue gas waste heat recovery unit (400) is connected to the inlet of the active constant temperature energy storage unit (100) to heat the low temperature return water with high temperature flue gas through a closed circulation system and transfer it to the active constant temperature energy storage unit (100), so as to realize the dual-path synchronous recovery of flue gas waste heat and cylinder liner water waste heat.

2. The ship heat recovery system according to claim 1, characterized in that, The active constant temperature energy storage unit (100) includes an active constant temperature energy storage chamber (S3), a variable frequency hot water circulation pump (S1), and a first plate heat exchanger (S2) connected in sequence through pipelines; the outlet pipe of the first plate heat exchanger (S2) is connected to the intelligent auxiliary heating unit (200) and the active constant temperature energy storage chamber (S3). The active constant temperature energy storage unit (100) also includes a first intelligent control box (S4), multiple temperature sensor components, pressure sensors, and liquid level sensor groups; the first intelligent control box (S4) establishes a linkage control connection with the variable frequency hot water circulation pump (S1), temperature sensor components, pressure sensors, and liquid level sensor groups; the first intelligent control box (S4) dynamically controls the start-up, shutdown, and operating power of the variable frequency hot water circulation pump (S1) based on the real-time water temperature data fed back by the temperature sensor components and the cabin pressure data fed back by the pressure sensors, thereby realizing the dynamic and precise regulation of the water temperature in the active constant temperature energy storage chamber (S3) by the first plate heat exchanger (S2), with a temperature control response time ≤1s and a temperature fluctuation ≤±0.5℃.

3. The ship heat recovery system according to claim 1, characterized in that, The surface of the active constant temperature energy storage chamber (S3) is covered with a composite rock wool insulation layer (W1) with a thickness of 90~110mm. The outer side of the composite rock wool insulation layer is covered with a 0.5mm thick galvanized iron sheet, and the 24-hour heat loss rate is ≤3%. The active constant temperature energy storage chamber (S3) is made of marine-grade stainless steel and has a working pressure of 0.3-0.5 MPa. The top of the active constant temperature energy storage chamber (S3) is equipped with a vacuum vent valve with precise pressure control, which has an opening pressure of 0.15 MPa and a closing pressure of 0.1 MPa to achieve coordinated stability of pressure and temperature inside the chamber.

4. The ship heat recovery system according to claim 2, characterized in that, The active constant temperature energy storage unit (100) also includes a flow regulating valve, a vacuum vent valve (PV01), a normally open valve, a vent valve (V107), a water supply valve (V108), and an isolation valve (V106); the liquid level sensor group includes a high liquid level sensor (LS001) and a low liquid level sensor (LS002). The flow regulating valve is located on the inlet and outlet pipes connecting the active constant temperature energy storage chamber (S3), which can accurately control the inlet and outlet water volume of the active constant temperature energy storage chamber (S3) to ensure the balance between energy storage and energy supply; the high liquid level sensor (LS001) and low liquid level sensor (LS002) are respectively installed on the upper and lower parts of the active constant temperature energy storage chamber (S3), and form a linkage control with the water supply valve (V108) and the drain valve (V107) to prevent the pump from running dry and the chamber from overflowing; the vacuum vent valve (PV01) is located on the top of the active constant temperature energy storage chamber (S3) to maintain the pressure balance inside the chamber and reduce heat loss in conjunction with the composite rock wool insulation layer; the normally open valve is located on the inlet and outlet pipes of the first plate heat exchanger (S2); The water supply valve (V108) is located on the upper part of the active constant temperature energy storage chamber (S3) and is used to control the external water source to enter the active constant temperature energy storage chamber (S3) to achieve water supply. The drain valve (V107) is located at the lower part of the active constant temperature energy storage tank (S3) and is used to drain the water in the active constant temperature energy storage tank (S3). The vent valve (V107) and the isolation valve (V106) are used to realize the venting and isolation functions, respectively; The temperature sensor assembly includes a first temperature sensor (T101), a second temperature sensor (T102), and a third temperature sensor (T103); the first temperature sensor (T101) is fixed on the active constant temperature energy storage chamber (S3) to monitor the water temperature inside the chamber in real time; the second temperature sensor (T102) and the third temperature sensor (T103) are respectively arranged on the inlet pipe and outlet pipe of the first plate heat exchanger (S2).

5. The ship heat recovery system according to claim 4, characterized in that, The vacuum vent valve (PV01) has an opening pressure of 0.15 MPa and a closing pressure of 0.1 MPa; the first temperature sensor (T101), the second temperature sensor (T102), and the third temperature sensor (T103) have a measurement range of 0-100℃ and a measurement accuracy of ±0.5℃.

6. The ship heat recovery system according to claim 1, characterized in that, The intelligent auxiliary heating unit (200) includes an intelligent heating controller (F2) and an auxiliary heater (F1), a fourth temperature sensor (G101), and a fifth temperature sensor (G102) electrically connected to the intelligent heating controller (F2); the fourth temperature sensor (G101) and the fifth temperature sensor (G102) are respectively installed on the inlet and outlet pipes of the intelligent auxiliary heating unit (200) to form a closed-loop monitoring.

7. The ship heat recovery system according to claim 1, characterized in that, The heat energy distribution and waste heat recovery unit (300) includes a dual-pump redundant variable frequency circulating pump group (R1), a multi-functional heat energy distribution terminal (R2), a cylinder liner water direct supply heat exchanger (R3), a second intelligent control box (R4), and a first valve assembly. The dual-pump redundant variable frequency circulating pump group (R1) is connected to the multi-functional heat energy distribution terminal (R2), the multi-functional heat energy distribution terminal (R2) is connected to the cylinder liner water direct supply heat exchanger (R3), and the second intelligent control box (R4) is connected to the first valve assembly. It is used to quickly switch the water flow path according to the water temperature, with a switching response time ≤2s.

8. The ship heat recovery system according to claim 1, characterized in that, The flue gas waste heat recovery unit (400) includes an exhaust gas economizer (E1), a dual-pump redundant variable frequency high-temperature water circulation pump group (E2), a high-temperature water heat exchanger (E3), a third intelligent control box (E4), a second valve assembly, and a waste heat recovery temperature sensor; the exhaust gas economizer (E1) is installed on the main unit's exhaust pipe. The dual-pump redundant variable frequency high-temperature water circulation pump set (E2) is connected to the exhaust gas economizer (E1) and the high-temperature water heat exchanger (E3) to form a closed-loop circulating water system, reducing heat loss and achieving efficient recovery and transmission of waste heat from flue gas. The waste heat recovery temperature sensor is installed on the inlet and outlet pipes of the high-temperature water heat exchanger (E3). The third intelligent control box (E4) is electrically connected to the dual-pump redundant variable frequency high-temperature water circulation pump set (E2) and the waste heat recovery temperature sensor, and is used to control the operating status of the pump set to achieve dual-path coordinated recovery of waste heat from cylinder liner water.

9. A method for recovering ship heat energy, based on the ship heat energy recovery system according to any one of claims 1 to 8, characterized in that, This includes the heat recovery process during normal operation of the host and the heat supply process when the host is stopped. The heat recovery process during normal operation of the main unit is as follows: T1: The active constant temperature energy storage unit (100) is started, and the variable frequency hot water circulation pump (S1) starts according to the initial temperature inside the chamber monitored by the first temperature sensor (T101). The water temperature inside the chamber is adjusted through the first plate heat exchanger (S2) to stabilize the temperature inside the chamber at the first threshold. Combined with the composite rock wool insulation layer, it ensures that the heat loss is ≤3% in 24 hours. T2: Hot water in the cabin enters the intelligent auxiliary heating unit (200). The fourth temperature sensor (G101) and the fifth temperature sensor (G102) monitor the water temperature. If the water temperature is lower than the first threshold, the auxiliary heater (F1) starts micro-heating to the first threshold. Otherwise, the hot water flows directly into the heat energy distribution and waste heat recovery unit (300). T3: Hot water is transported to the multi-functional heat energy distribution terminal (R2) via a dual-pump redundant variable frequency circulating pump set (R1) to provide energy to the heat-requiring equipment and then forms low-temperature return water; T4: After the low-temperature return water is heated by the cylinder liner water direct supply heat exchanger (R3), the second intelligent control box (R4) switches the water flow path according to the water temperature. When the water temperature is lower than the second threshold (85℃), it flows into the high-temperature water heat exchanger (E3) to be further heated by the waste heat of the flue gas and then flows back to the active constant temperature energy storage chamber (S3). When the water temperature is not lower than the second threshold, it flows directly back to the active constant temperature energy storage chamber (S3) to achieve simultaneous recovery and circulation of dual waste heat. T5: The flue gas waste heat recovery unit (400) operates synchronously. The waste gas economizer (E1) absorbs the heat energy of the high-temperature flue gas from the main unit and heats the circulating water in the closed-loop system. The high-temperature water heat exchanger (E3) heats the low-temperature return water. It does not interfere with the cylinder liner water waste heat recovery and the dual-path collaborative recovery efficiency is ≥88%. The thermal energy supply process when the host is stopped includes the following steps: T11: The flue gas waste heat recovery unit (400) and the cylinder liner water direct supply heat exchanger (R3) stop working. The active constant temperature energy storage chamber (S3) maintains the third threshold constant temperature under the pressure balance of the composite rock wool insulation layer and the vacuum vent valve. As the only core heat source of the system, it realizes active energy release. T12: The second intelligent control box (R4) of the heat energy distribution and waste heat recovery unit (300) switches the valve so that low-temperature return water flows directly into the active constant temperature energy storage unit (100). T13: The active constant temperature energy storage unit (100) starts the reverse heat exchange function, releases heat energy with the active constant temperature energy storage chamber (S3) as the heat source, and heats the low temperature return water to the fourth threshold through the first plate heat exchanger (S2) without relying on an external heat source. T14: When hot water of the fourth threshold enters the intelligent auxiliary heating unit (200), the fourth temperature sensor (G101) detects that the water temperature is below 83°C. When this is detected, the intelligent heating controller (F2) starts the auxiliary heater (F1) to perform micro-heating and raise the water temperature to 85°C. T15: Hot water at 85°C is delivered to the multi-functional heat distribution terminal (R2) to continuously supply energy to the ship's heat-requiring equipment.

10. The ship heat energy recovery method according to claim 9, characterized in that, The temperature range of the first threshold is 80~85℃; the temperature range of the second threshold is 83~88℃; the temperature range of the third threshold is 78~88℃; and the temperature range of the fourth threshold is 68~72℃.

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