A marine multi-mode cooling system

Abstract

The present application relates to the technical field of ship cabin cooling, and discloses a marine multi-mode cooling system, comprising a three-way valve one, a three-way valve two, a seawater direct heat exchange branch, a seawater pump driven heat exchange branch, a seawater compression refrigeration heat exchange branch and a controller. The seawater direct heat exchange branch comprises a cooling liquid pump and a flat plate heat exchanger arranged on a cabin bottom; the seawater pump driven heat exchange branch comprises a seawater pump and a seawater heat exchanger one; the seawater compression refrigeration heat exchange branch comprises an evaporator, a vapor compression refrigeration device and a seawater heat exchanger two; the controller is used for controlling the start-stop state of each heat exchange branch to perform separate or coupled heat exchange modes based on the cooling demand temperature of a user terminal device, and controlling the opening degree of the three-way valve one and the three-way valve two according to the liquid supply temperature difference of each heat exchange branch to adjust the cooling liquid shunt ratio and the seawater shunt ratio in each heat exchange branch. The present application solves the technical problems of high energy consumption, low reliability and ineffective cooperation of different cooling modes existing in the prior art.

Description

Technical Field

[0001] This invention relates to the field of ship cabin cooling technology, specifically a marine multi-mode cooling system. Background Technology

[0002] During ship operation, the cooling system is crucial for ensuring the normal operation of user-end equipment such as ship propulsion and electrical systems. Currently, marine cooling systems typically employ a single cooling mode, such as relying on seawater cooling systems during navigation. Seawater is pumped into heat exchangers to remove heat generated by the equipment. However, this seawater cooling system presents several problems: firstly, the continuous operation of the seawater pumps consumes a significant amount of electricity, increasing energy costs. When user-end equipment requires coolant at lower or constant temperatures, vapor compression refrigeration equipment is usually used. However, existing vapor compression refrigeration equipment operates independently of the seawater cooling system during navigation, increasing equipment and maintenance costs and lacking effective coordinated control, resulting in high overall energy consumption and low resource utilization efficiency. Therefore, developing an integrated, low-energy-consumption, and highly reliable marine cooling system has become an urgent technical challenge in this field. Summary of the Invention

[0003] To address the technical problems existing in the prior art, this invention provides a marine multi-mode cooling system, which solves the technical problems of high energy consumption, low reliability, and ineffective coordination of different cooling modes in existing marine cooling systems.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention discloses a marine multi-mode cooling system, comprising: a three-way valve one, a three-way valve two, a seawater direct heat exchange branch, a seawater pump-driven heat exchange branch, a seawater compression refrigeration heat exchange branch, and a controller.

[0006] The direct seawater heat exchange branch includes a coolant pump and a flat plate heat exchanger installed at the bottom of the tank. The coolant pump is used to drive a portion of the coolant output from the user-end equipment to be diverted into the flat plate heat exchanger through a three-way valve. The coolant in the flat plate heat exchanger exchanges heat with the seawater outside the tank and / or the ballast tank water inside the tank.

[0007] The seawater pump-driven heat exchange branch includes a seawater pump and a seawater heat exchanger. The coolant pump is also used to drive another part of the coolant output from the user-end equipment to enter the seawater heat exchanger through a three-way valve. Here, the coolant exchanges heat with the seawater driven by the seawater pump and diverted into the seawater heat exchanger through a three-way valve.

[0008] The seawater compression refrigeration heat exchange branch includes an evaporator, a vapor compression refrigeration device, and a second seawater heat exchanger. The coolant output from the heat exchange branch driven by the seawater pump enters the evaporator and exchanges heat with the refrigerant provided by the vapor compression refrigeration device. Subsequently, the coolant output from the direct seawater heat exchange branch is collected and returned to the user-end equipment for cooling. After heat exchange, the refrigerant enters the second seawater heat exchanger and dissipates heat with the seawater that is driven by the seawater pump and diverted into the second seawater heat exchanger by the three-way valve.

[0009] The controller is used to control the start and stop status of each heat exchange branch based on the cooling demand temperature of the user terminal equipment to perform individual or coupled heat exchange modes, and to control the opening degree of three-way valve one and three-way valve two according to the supply liquid temperature difference of each heat exchange branch, so as to adjust the coolant diversion ratio and seawater diversion ratio in each heat exchange branch.

[0010] As a further improvement to the above solution, the cooling system also includes a temperature acquisition module.

[0011] The temperature acquisition module is used to acquire in real time the coolant temperature t1 output from the direct seawater heat exchange branch, the total supply temperature t2 after being collected and returned to the user terminal equipment, the coolant temperature t3 output from the seawater pump-driven heat exchange branch, and the coolant temperature t4 output from the seawater compression refrigeration heat exchange branch.

[0012] The controller is also used to set an incremental temperature threshold of one to five based on the cooling requirements of the user terminal equipment, and to make the following control decisions in conjunction with the real-time collected temperature values:

[0013] When t2 is greater than temperature threshold one and less than temperature threshold two, the coolant pump is controlled to run, and the opening of the three-way valve one flowing to the flat plate heat exchanger is adjusted to x%, x∈(0,100), so that coolant passes through each heat exchange branch, and the seawater pump and the vapor compression refrigeration equipment are both in the shutdown state.

[0014] When t2 is not less than temperature threshold two and less than temperature threshold three, the coolant pump is controlled to run, the opening of the three-way valve one flowing to the flat plate heat exchanger is adjusted to 100%, and the opening of the three-way valve one flowing to the seawater heat exchanger two is 0. The seawater pump and the vapor compression refrigeration equipment are both in a stopped state.

[0015] When t2 is not less than temperature threshold three and less than temperature threshold four, control the operation of the coolant pump and seawater pump, adjust the opening of the three-way valve one flowing to the flat plate heat exchanger to x%, so that coolant flows through each heat exchange branch, and adjust the opening of the three-way valve two flowing to the seawater heat exchanger one to 100%, and the vapor compression refrigeration equipment is in a shutdown state; at this time, determine whether t1 is greater than t3. If it is, increase the opening of the three-way valve one flowing to the seawater heat exchanger one to increase the coolant flow rate of its heat exchange branch and downstream heat exchange branch, otherwise decrease it.

[0016] When t2 is not less than temperature threshold 4 and less than temperature threshold 5, control the operation of the coolant pump, seawater pump and vapor compression refrigeration equipment; at this time, determine whether t1 is greater than t4. If so, increase the opening of the three-way valve one flowing to the seawater heat exchanger one to increase the coolant flow rate in its heat exchange branch and downstream heat exchange branch, otherwise decrease it; at the same time, determine whether t3-t4 is less than a preset temperature difference threshold. If so, increase the opening of the three-way valve two flowing to the seawater heat exchanger two to increase its seawater flow rate, otherwise decrease it.

[0017] As a further improvement to the above scheme, the lower limit of the cooling requirement temperature of the user terminal device is T1, and the upper limit is T2; wherein, the first temperature threshold is T1, the second temperature threshold is T1+3℃, the third temperature threshold is T2-5℃, the fourth temperature threshold is T2-3℃, and the fifth temperature threshold is T2-1℃; the temperature difference threshold is 3℃.

[0018] As a further improvement to the above solution, the temperature acquisition module includes temperature transmitter one, temperature transmitter two, temperature transmitter three and temperature transmitter four, which are used to acquire t1, t2, t3 and t4 in sequence.

[0019] The direct seawater heat exchange branch also includes check valve one, a liquid storage tank, a shut-off valve two, and another check valve two. The coolant output end of the flat plate heat exchanger is connected to the liquid storage tank via a pipeline, and temperature transmitter one and check valve one are sequentially installed on this pipeline. The output end of the liquid storage tank is sequentially connected to temperature transmitter two, shut-off valve two, coolant pump, and check valve two via a pipeline, and finally connected to the coolant input end of the user-end equipment. The coolant output end of the user-end equipment is connected to the inlet of three-way valve one, and the two outlets of three-way valve one are respectively connected to the coolant input ends of the flat plate heat exchanger and the seawater heat exchanger one.

[0020] The seawater compression refrigeration heat exchange branch also includes check valve four; the coolant output end of seawater heat exchanger one is connected to the coolant input end of the evaporator through a pipe, and temperature transmitter three is installed on this section of pipe; the coolant output end of the evaporator is connected to the water storage tank through a pipe, and temperature transmitter four and check valve four are installed sequentially on this section of pipe.

[0021] As a further improvement to the above scheme, the seawater pump-driven heat exchange branch also includes shut-off valve four, check valve five, check valve six, and check valve seven; the input end of shut-off valve four is connected to the seawater inlet, and the output end of shut-off valve four is connected to the inlet of the seawater pump, check valve five, and three-way valve two in sequence through pipes; the two outlets of three-way valve two are respectively connected to the seawater input ends of seawater heat exchanger one and seawater heat exchanger two; the seawater output end of seawater heat exchanger one is connected to the seawater outlet through a pipe, and check valve six is ​​installed on this section of pipe; the seawater output end of seawater heat exchanger two is connected to the seawater outlet through a pipe, and check valve seven is installed on this section of pipe.

[0022] As a further improvement to the above scheme, a coarse filter I, a coarse filter II, and a fine filter are installed sequentially between the seawater inlet and the four gate valves in the direction of seawater transmission. The filtration accuracies of the three filters are 3mm, 0.5mm, and 0.1mm, respectively.

[0023] As a further improvement to the above scheme, the direct seawater heat exchange branch also includes an expansion tank, shut-off valve one, shut-off valve three, a coolant backup pump, and check valve three; the input end of the expansion tank is connected to one end of shut-off valve one, and the other end of shut-off valve one is connected in parallel to the pipeline between the liquid storage tank and the temperature transmitter two; shut-off valve three, the coolant backup pump, and check valve three are connected in sequence to form a backup flow path connected in parallel between the temperature transmitter two and the coolant input end of the user-end equipment.

[0024] As a further improvement to the above scheme, the vapor compression refrigeration equipment includes a throttling device and a compressor; the input end of the throttling device is connected to the refrigerant output end of the second seawater heat exchanger, the output end of the throttling device is connected to the refrigerant input end of the evaporator, the refrigerant output end of the evaporator is connected to the input end of the compressor, and the output end of the compressor is connected to the refrigerant input end of the second seawater heat exchanger.

[0025] As a further improvement to the above scheme, the controller is also used to calculate the heat load change rate ΔQ / Δt of the cooling system in real time. The heat load ΔQ of the cooling system is positively correlated with the total power P of the user-end equipment, and makes the following decisions:

[0026] If the rate of change of heat load is less than a preset rate of change threshold, then control the coolant pump to maintain the initial speed V. c0 ;

[0027] If the rate of change of heat load is not less than the rate of change threshold one and less than a preset rate of change threshold two, then control the coolant pump to increase linearly.

[0028] If the rate of change of heat load is not less than the threshold value of 2, then control the coolant pump to increase its speed stepwise to the rated speed V. c1 Among them, V c0 :V c1 =1:1.1~1.2.

[0029] As a further improvement to the above solution, the controller is also used to acquire the seawater temperature at the seawater inlet in real time and make the following decisions:

[0030] If the seawater temperature is not higher than a preset temperature threshold 'a', then control the seawater pump to maintain its initial speed V. s0 ;

[0031] If the seawater temperature is higher than temperature threshold a but not higher than a preset temperature threshold b, the speed of the seawater pump will be dynamically increased or decreased within ±15%.

[0032] If the seawater temperature is higher than the temperature threshold b but not higher than a preset temperature threshold c, then the seawater pump speed is controlled linearly according to the seawater temperature.

[0033] If the seawater temperature is higher than the temperature threshold c, then the seawater pump will be locked at its rated speed V. s1 Among them, V s0 :V s1 =1:1.1~1.3; a<b<c.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. The marine multi-mode cooling system disclosed in this invention constructs a multi-mode adaptive cooling path by designing three heat exchange branches, and uses two three-way valves to regulate the flow of coolant and seawater to achieve a dynamic balance between cooling efficiency and energy consumption. This enables coordinated control of the vapor compression refrigeration equipment and the seawater cooling system, resulting in high reliability.

[0036] 2. This invention collects the temperature of key nodes in the coolant flow path and refines the control logic based on the judgment of multi-level temperature thresholds to realize the phased activation of the cooling mode and reduce energy consumption; it also judges the priority of the cooling path and the valve adjustment range according to the actual temperature difference to improve the temperature control accuracy.

[0037] 3. This invention ensures stable system operation by installing multiple check valves in the coolant and seawater pipelines, providing unidirectional flow and backflow prevention capabilities, and clearly defining pathways for subsequent branch maintenance and fault location. Simultaneously, a multi-stage filter at the seawater inlet prevents impurities in the seawater from clogging the heat exchanger, extending equipment life and significantly reducing maintenance frequency and failure rate, adapting to complex sea conditions. Furthermore, the inclusion of a coolant backup pump bypass improves system redundancy and reliability, ensuring uninterrupted cooling of critical equipment. The expansion tank also enables pressure buffering and emergency operation modes, enhancing safety.

[0038] 4. The control strategy of the present invention can also dynamically control the speed of the coolant pump according to the rate of change of heat load, improve energy consumption efficiency, save electricity when the heat load is low, and respond in time when the heat load rises rapidly to prevent overheating.

[0039] 5. The control strategy of the present invention can also adjust the speed of the seawater pump based on changes in seawater temperature. As the seawater temperature rises, the flow rate is appropriately increased to maintain heat exchange efficiency, avoid excessive pumping at low sea temperatures, and achieve energy-saving operation. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the marine multi-mode cooling system in Embodiment 1 of the present invention.

[0041] In the diagram: 11. Flat plate heat exchanger; 12. Temperature transmitter 1; 13. Check valve 1; 14. Liquid storage tank; 15. Expansion tank; 16. Shut-off valve 1; 17. Temperature transmitter 2; 18. Shut-off valve 2; 19. Coolant pump; 110. Check valve 2; 111. Shut-off valve 3; 112. Coolant standby pump; 113. Check valve 3; 21. Three-way valve 1; 22. Seawater heat exchanger 1; 23. Temperature... Temperature transmitter 3; 31. Evaporator; 32. Compressor; 33. Seawater heat exchanger 2; 34. Throttling device; 35. Temperature transmitter 4; 36. Check valve 4; 41. Coarse filter 1; 42. Coarse filter 2; 43. Fine filter; 44. Shut-off valve 4; 45. Seawater pump; 46. Check valve 5; 47. Three-way valve 2; 48. Check valve 6; 49. Check valve 7; 51. User-end equipment. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see Figure 1 This embodiment provides a marine multi-mode cooling system, including a three-way valve 21, a three-way valve 47, a seawater direct heat exchange branch, a seawater pump-driven heat exchange branch, a seawater compression refrigeration heat exchange branch, and a controller (not shown). It may also include a temperature acquisition module.

[0044] Both three-way valve 1 (21) and three-way valve 2 (47) are electrically operated three-way valves. Three-way valve 1 (21) is used for distributing coolant, and its valve body can be made of stainless steel. Three-way valve 2 (47) is used for distributing seawater, and its valve body can be made of titanium alloy to enhance corrosion resistance when in contact with seawater. The coolant can be an aqueous solution of ethylene glycol, such as No. 65 antifreeze.

[0045] The direct seawater heat exchange branch includes a coolant pump 19 and a flat plate heat exchanger 11 installed at the bottom of the tank. The coolant pump 19 drives a portion of the coolant output from the user terminal equipment 51 to be diverted through a three-way valve 21 into the flat plate heat exchanger 11. The coolant in the flat plate heat exchanger 11 exchanges heat with the seawater outside the tank and / or the ballast tank water inside the tank.

[0046] In some embodiments, the flat plate heat exchanger 11 can be part of the hull structure, i.e., a heat-exchange plate. Microchannels can be etched into the bottom hull plate, providing heat exchange capacity while maintaining hull structural strength. It does not require any space within the hull. The heat exchanger's two sides directly contact seawater and ballast tank water, eliminating contact thermal resistance caused by its installation on the hull plate. Alternatively, if a modular and detachable design is considered, the flat plate heat exchanger 11 can be customized according to the hull's curvature and tightly fixed to the hull plate. This design facilitates inspection and maintenance. However, the shape of the flat plate heat exchanger must also be customized to fit the hull structure during installation to reduce contact thermal resistance. Specifically, the flat plate heat exchanger 11 can be installed at the bottom of the ballast tank, where the hull can contact cooling water on two sides, resulting in better heat exchange compared to contacting seawater on one side and air on the other.

[0047] The direct seawater heat exchange branch also includes check valve 13, liquid storage tank 14, shut-off valve 18, and check valve 110. The coolant output end of the flat plate heat exchanger 11 is connected to the liquid storage tank 14 via a pipeline, and temperature transmitter 12 and check valve 13 are sequentially installed on this pipeline. The output end of the liquid storage tank 14 is sequentially connected to temperature transmitter 17, shut-off valve 18, coolant pump 19, and check valve 110 via a pipeline, and finally connected to the coolant input end of the user-end equipment 51. The coolant output end of the user-end equipment 51 is connected to the inlet of three-way valve 21, and the two outlets of three-way valve 21 are respectively connected to the coolant input ends of the flat plate heat exchanger 11 and the seawater heat exchanger 22.

[0048] The direct seawater heat exchange branch also includes an expansion tank 15, a shut-off valve 16, a shut-off valve 111, a coolant standby pump 112, and a check valve 113. The input end of the expansion tank 15 is connected to one end of the shut-off valve 16, and the other end of the shut-off valve 16 is connected in parallel to the pipeline between the liquid storage tank 14 and the temperature transmitter 17. During normal system operation, the shut-off valve 16 is normally open and only needs to be closed when the expansion tank 15 is being maintained or replaced. Because the coolant expands when the temperature rises and contracts when the temperature falls, the expansion tank 15 can buffer and store the expanded volume when the coolant expands, and pump the coolant back into the system to fill the volume gap when the coolant contracts. By buffering volume changes, the expansion tank 15 can stabilize the system pressure within the designed "operating pressure range," reducing the impact of drastic pressure fluctuations on equipment such as pumps, valves, and sensors.

[0049] In addition, the shut-off valve 111, the coolant backup pump 112, and the check valve 113 are connected in sequence to form a backup flow path connected in parallel between the temperature transmitter 17 and the coolant input terminal of the user-end equipment 51. Since the coolant pump 19 is responsible for the circulation of coolant and is the core of the cooling system, if the coolant pump 19 and the valves before and after it fail, the controller can adjust the flow path to stop working, and the backup flow path will be activated. This redundancy setting can ensure the continuous operation of the system and enhance reliability.

[0050] In the mode where the seawater direct heat exchange branch is cooled separately, the opening of the three-way valve 21 to the seawater pump-driven heat exchange branch is small or completely closed. The heat from this branch can be directly dissipated to the seawater outside the tank and the ballast water inside the tank by the flat plate heat exchanger 11. The entire process only requires the pumping of the coolant pump 19, without the intervention of the main power supply devices in other heat exchange branches. Under the condition of meeting basic cooling requirements, energy consumption can be effectively saved. The coolant after heat exchange by the flat plate heat exchanger 11 passes sequentially through the temperature transmitter 12, check valve 13, liquid storage tank 14, temperature transmitter 17, shut-off valve 18, coolant pump 19, and check valve 110, and finally enters the coolant input terminal of the user-end equipment 51.

[0051] The seawater pump-driven heat exchange branch includes a seawater pump 45 and a seawater heat exchanger 22; the coolant pump 19 is also used to drive another part of the coolant output by the user terminal equipment 51 to be diverted into the seawater heat exchanger 22 through the three-way valve 21, where the coolant exchanges heat with the seawater driven by the seawater pump 45 and diverted into the seawater heat exchanger 22 through the three-way valve 47.

[0052] The seawater pump-driven heat exchange branch also includes shut-off valve 44, check valve 46, check valve 48, and check valve 49. The input end of shut-off valve 44 is connected to the seawater inlet, and the output end of shut-off valve 44 is connected to the inlet of seawater pump 45, check valve 46, and three-way valve 47 in sequence through pipes. The two outlets of three-way valve 47 are respectively connected to the seawater inlet of seawater heat exchanger 22 and seawater heat exchanger 33. The seawater outlet of seawater heat exchanger 22 is connected to the seawater outlet through a pipe, and check valve 6 48 is installed on this section of pipe. The seawater outlet of seawater heat exchanger 33 is connected to the seawater outlet through a pipe, and check valve 7 49 is installed on this section of pipe.

[0053] In this embodiment, a coarse filter 41, a coarse filter 42, and a fine filter 43 are sequentially installed between the seawater inlet and the shut-off valve 44 along the seawater transmission direction. The filtration accuracies of the three filters are 3mm, 0.5mm, and 0.1mm, respectively, which can effectively filter larger impurities such as silt in the seawater and reduce wear or blockage of components such as heat exchangers and pumps.

[0054] In the coupled operation mode of the direct seawater heat exchange branch and the seawater pump-driven heat exchange branch, the opening of the three-way valve 21, which diverts the flow to the seawater heat exchanger 22, is appropriately increased to increase the flow rate of the coolant entering the seawater heat exchanger 22. At this time, the seawater pump 45 participates in the operation, drawing seawater from outside the hull (i.e., the ocean) into the seawater heat exchanger 22 to exchange heat with the coolant passing through the seawater heat exchanger 22. The heat from this branch is carried away by the seawater and discharged outside the hull. Since the seawater in the direct seawater heat exchange branch can be renewed, when the temperature of the seawater outside the hull is suitable, it can also cool the coolant, and the heat in the coolant is carried away by the seawater outside the hull.

[0055] The seawater compression refrigeration heat exchange branch includes an evaporator 31, a vapor compression refrigeration device, and a second seawater heat exchanger 33. The coolant output from the seawater pump-driven heat exchange branch enters the evaporator 31 and exchanges heat with the refrigerant provided by the vapor compression refrigeration device. Subsequently, the coolant is collected with the coolant output from the direct seawater heat exchange branch and returned to the user-end equipment 51 for cooling. After heat exchange, the refrigerant enters the second seawater heat exchanger 33 and dissipates heat with the seawater that is driven by the seawater pump 45 and diverted into the second seawater heat exchanger 33 by the three-way valve 47.

[0056] The seawater compression refrigeration heat exchange branch also includes check valve 36; the coolant output end of the seawater heat exchanger 22 is connected to the coolant input end of the evaporator 31 through a pipe, and the temperature transmitter 23 is installed on this section of the pipe; the coolant output end of the evaporator 31 is connected to the water storage tank through a pipe, and the temperature transmitter 35 and check valve 36 are installed on this section of the pipe in sequence.

[0057] The vapor compression refrigeration equipment includes a throttling device 34 and a compressor 32; the input end of the throttling device 34 is connected to the refrigerant output end of the second seawater heat exchanger 33, the output end of the throttling device 34 is connected to the refrigerant input end of the evaporator 31, the refrigerant output end of the evaporator 31 is connected to the input end of the compressor 32, and the output end of the compressor 32 is connected to the refrigerant input end of the second seawater heat exchanger 33.

[0058] It should be noted that when the seawater compression refrigeration heat exchange branch does not participate in the coupling operation, the coolant after heat exchange in the seawater pump drives the heat exchange branch to enter the evaporator 31 in the seawater compression refrigeration heat exchange branch. At this time, the vapor compression refrigeration equipment in the seawater compression refrigeration heat exchange branch does not work. The coolant output from the evaporator 31 enters the liquid storage tank 16 through the check valve 36. In the liquid storage tank 16, it mixes with the coolant output from the plate heat exchanger 11 and is then transported together to the user-end equipment 51.

[0059] In the coupled operation mode of the seawater direct heat exchange branch, the seawater pump-driven heat exchange branch, and the seawater compression refrigeration heat exchange branch, compressor 32 is in operation. The refrigerant output by compressor 32 is in a high-pressure, high-temperature gaseous state. At this time, seawater heat exchanger 33 acts as a condenser, cooling and condensing the high-pressure, high-temperature refrigerant discharged by compressor 32 into a high-pressure, low-temperature liquid refrigerant. Throttling device 34 throttles and reduces the pressure of the high-pressure liquid refrigerant output by seawater heat exchanger 33, lowering it to the low-pressure state corresponding to evaporator 31. During the pressure reduction process, some refrigerant flashes into vapor, absorbing its own heat, causing the refrigerant temperature to drop sharply, forming a low-temperature, low-pressure gas-liquid mixture. Evaporator 31 allows the low-pressure, low-temperature refrigerant from throttling device 34 to absorb heat from the object being cooled, that is, to further exchange heat with the coolant output by seawater heat exchanger 22. At the same time, three-way valve 247 also diverts a portion of the seawater to seawater heat exchanger 233, where it exchanges heat with the refrigerant flowing through it. The heat of the coolant in the seawater compression refrigeration heat exchange branch is eventually carried away by the seawater and discharged outside the cabin.

[0060] In some embodiments, both seawater heat exchangers can be titanium alloy plate heat exchangers, formed by stacked corrugated metal sheets to create rectangular channels, resulting in high heat exchange efficiency and a compact structure that is easy to disassemble and clean. The evaporator 31 can be a plate heat exchanger or a printed circuit board microchannel heat exchanger (PCHE), which enhances heat exchange while minimizing equipment size and saving interior space. The compressor 32 can be a variable frequency refrigeration compressor. The throttling device 34 is an electronic expansion valve.

[0061] The temperature acquisition module is used to acquire in real time the coolant temperature t1 output from the direct seawater heat exchange branch, the total supply temperature t2 after being collected and returned to the user terminal equipment 51, the coolant temperature t3 output from the seawater pump-driven heat exchange branch, and the coolant temperature t4 output from the seawater compression refrigeration heat exchange branch. The temperature acquisition module includes temperature transmitter 12, temperature transmitter 17, temperature transmitter 23, and temperature transmitter 35, which are used to acquire t1, t2, t3, and t4 in sequence.

[0062] The controller is used to control the start and stop status of each heat exchange branch based on the cooling demand temperature of the user terminal device 51 to perform individual or coupled heat exchange modes, and to control the opening degree of three-way valve 21 and three-way valve 47 according to the supply liquid temperature difference of each heat exchange branch, so as to adjust the coolant diversion ratio and seawater diversion ratio in each heat exchange branch.

[0063] Specifically, the controller is further configured to set incremental temperature thresholds one to five based on the cooling demand temperature of the user terminal device 51. In this embodiment, the lower limit of the cooling demand temperature of the user terminal device 51 is T1, and the upper limit is T2; wherein, temperature threshold one is T1, temperature threshold two is T1+3℃, temperature threshold three is T2-5℃, temperature threshold four is T2-3℃, and temperature threshold five is T2-1℃; the temperature difference threshold is 3℃.

[0064] The controller, combining the preset thresholds and the real-time temperature data, makes the following control decisions:

[0065] When T1≤t2<T1+3℃, only the direct seawater heat exchange branch is in operation, while the seawater pump-driven heat exchange branch and the seawater compression refrigeration heat exchange branch are in shutdown. At this time, the coolant pump 19 is controlled to operate, and the opening of the three-way valve 21 flowing to the flat plate heat exchanger 11 is adjusted to x%, x∈(0,100), so that coolant flows through each heat exchange branch, and the seawater pump 45 and the vapor compression refrigeration equipment are both in shutdown.

[0066] When T1+3℃≤t2<T2-5℃, only the direct seawater heat exchange branch is in operation, while the seawater pump-driven heat exchange branch and the seawater compression refrigeration heat exchange branch are in shutdown. At this time, the coolant pump 19 is controlled to operate, the opening of the three-way valve 21 flowing to the flat plate heat exchanger 11 is adjusted to 100%, and the opening of the valve flowing to the seawater heat exchanger 33 is 0. The seawater pump 45 and the vapor compression refrigeration equipment are both in shutdown.

[0067] When T2-5℃≤t2<T2-3℃, the direct seawater heat exchange branch and the seawater pump-driven heat exchange branch are both in operation. At this time, the coolant pump 19 and the seawater pump 45 are controlled to operate. The opening of the three-way valve 21 flowing to the flat plate heat exchanger 11 is adjusted to x%, so that coolant flows through each heat exchange branch. The opening of the three-way valve 47 flowing to the seawater heat exchanger 22 is adjusted to 100% (i.e., the opening of the valve flowing to the seawater heat exchanger 33 is 0%). The vapor compression refrigeration equipment is in a shutdown state. At this time, it is determined whether t1 is greater than t3. If it is, it means that the heat exchange effect of the seawater pump-driven heat exchange branch is better and the heat dissipation is more sufficient. The opening of the three-way valve 21 flowing to the seawater heat exchanger 22 is increased to increase the coolant flow rate of its heat exchange branch and the downstream heat exchange branch. Otherwise, it is decreased.

[0068] When T2-3℃≤t2<T2-1℃, the direct seawater heat exchange branch, the seawater pump-driven heat exchange branch, and the seawater compression refrigeration heat exchange branch are all operating simultaneously. At this time, the coolant pump 19, seawater pump 45, and the vapor compression refrigeration equipment are controlled to operate. It is then determined whether t1 is greater than t4. If so, it indicates that the heat exchange effect of the seawater pump-driven heat exchange branch and the seawater compression refrigeration heat exchange branch is better, and the heat dissipation is more sufficient. The opening of the three-way valve 21 flowing to the seawater heat exchanger 22 is increased to improve the coolant flow rate in its heat exchange branch and downstream heat exchange branches; otherwise, it is decreased. Simultaneously, it is determined whether t3-t4 is less than 3℃. If so, it indicates that the heat dissipation of the seawater compression refrigeration heat exchange branch is insufficient compared to the seawater pump-driven heat exchange branch. The opening of the three-way valve 47 flowing to the seawater heat exchanger 33 is increased to improve its seawater flow rate; otherwise, it is decreased.

[0069] In some embodiments, both the coolant pump 19 and the seawater pump 45 are variable frequency pumps, and their speeds can be adjusted by a controller.

[0070] The controller is also used to calculate the heat load change rate ΔQ / Δt of the cooling system in real time. The heat load ΔQ of the cooling system is positively correlated with the total power P of the user terminal equipment 51, and makes the following decisions:

[0071] If the rate of change of heat load is less than a preset rate of change threshold (e.g., 2%), this is because the change in heat load of user-end equipment 51 is a minor disturbance to the total heat load of the system and no intervention is required. In this case, the coolant pump 19 is controlled to maintain a low initial speed V. c0 ;

[0072] If the rate of change of heat load is not less than the rate of change threshold one and less than a preset rate of change threshold two (e.g., 10%), this is because the change of heat load of user terminal equipment 51 is a moderate disturbance to the total heat load of the system and linear compensation is required. At this time, the coolant pump 19 is controlled to increase linearly.

[0073] If the rate of change of heat load is not less than the threshold value of change, this is because the change of heat load of user-end equipment 51 is a drastic disturbance to the total heat load of the system, and step response compensation is required. Therefore, the coolant pump 19 is controlled to step increase its speed to the rated speed V. c1 Among them, V c0 :V c1 =1:1.15.

[0074] The controller is also used to acquire the seawater temperature at the seawater inlet in real time and make the following decisions:

[0075] If the seawater temperature is not higher than a preset temperature threshold a (e.g., 10℃), then the seawater pump 45 is controlled to maintain a low initial speed V. s0 ;

[0076] If the seawater temperature is higher than temperature threshold a but not higher than a preset temperature threshold b (e.g., 20℃), the speed of the seawater pump 45 is dynamically adjusted within a range of ±15%.

[0077] If the seawater temperature is higher than temperature threshold b but not higher than a preset temperature threshold c (e.g., 32℃), the seawater pump speed will be controlled linearly according to the seawater temperature. For example, based on the current speed, the speed will increase by 5% per minute until the speed limit is reached.

[0078] If the seawater temperature is higher than the temperature threshold c, then control the seawater pump 45 to lock at the rated speed V. s1 Among them, V s0 :V s1 =1:1.2.

[0079] This invention proposes a multi-mode marine cooling system and control strategy. Utilizing the ship's hull structure with heat exchange capabilities, it achieves direct heat exchange between the cooling water of the refrigeration system and the seawater outside the hull, as well as the ballast tank water inside the hull. This significantly reduces the overall equipment volume. The system uses plate-type seawater heat exchangers, which, compared to traditional shell-and-tube heat exchangers, increase the heat transfer coefficient by 3-5 times and occupy only 1 / 3-1 / 5 of the space required for shell-and-tube heat exchangers. This system is particularly suitable for ships with high requirements for interior space. In the conventional heat exchange mode, only the direct seawater heat exchange branch needs to be operational, while the seawater pump-driven heat exchange branch and the seawater compression refrigeration heat exchange branch are shut down. Equipment such as seawater pump 45 and compressor 32 do not need to operate. Under higher heat exchange demands, both the direct seawater heat exchange branch and the seawater pump-driven heat exchange branch need to be operational simultaneously, while the seawater compression refrigeration heat exchange branch is shut down. Compared to the conventional heat exchange mode, this only adds the operation of seawater pump 45. Under extreme heat exchange demands, the direct seawater heat exchange branch, the seawater pump-driven heat exchange branch, and the seawater compression refrigeration heat exchange branch all operate simultaneously. During operation, compressor 32 is added to fully guarantee the cooling needs of onboard user equipment. Through the above multi-mode adaptive operating condition design, the operating frequency of seawater pump 45 and compressor 32 is reduced, significantly lowering the energy consumption of the cooling system. Simultaneously, the multi-mode heat exchange operating condition design addresses the risk of single-mode failure in existing systems. When one cooling module fails, the system can automatically switch to other modules. Furthermore, the core cooling water pumps employ a redundant configuration of one in operation and one on standby, ensuring the normal operation of critical onboard equipment and improving the overall reliability of the cooling system. Both coolant pump 19 and seawater pump 45 in this system are variable frequency pumps, and compressor 32 is a variable frequency refrigeration compressor. The pump speed can be adjusted based on parameters such as cooling load and seawater temperature, further improving the adaptive capability, saving energy and reducing consumption, and aligning with the trend of green and environmentally friendly development.

[0080] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A marine multi-mode cooling system, characterized in that, include: Three-way valve 1 (21); Three-way valve two (47); The direct seawater heat exchange branch includes a coolant pump (19) and a flat plate heat exchanger (11) installed at the bottom of the tank. The coolant pump (19) drives a portion of the coolant output from the user terminal equipment (51) to be diverted into the flat plate heat exchanger (11) through a three-way valve (21). The coolant in the flat plate heat exchanger (11) exchanges heat with the seawater outside the tank and / or the ballast tank water inside the tank. The seawater pump-driven heat exchange branch includes a seawater pump (45) and a seawater heat exchanger (22); the coolant pump (19) is also used to drive another part of the coolant output by the user terminal equipment (51) to flow into the seawater heat exchanger (22) through the three-way valve (21), where the coolant exchanges heat with the seawater driven by the seawater pump (45) and flowed into the seawater heat exchanger (22) through the three-way valve (47); The seawater compression refrigeration heat exchange branch includes an evaporator (31), a vapor compression refrigeration device, and a second seawater heat exchanger (33). The coolant output from the heat exchange branch driven by the seawater pump enters the evaporator (31) and exchanges heat with the refrigerant provided by the vapor compression refrigeration device. Then, the coolant output from the direct seawater heat exchange branch is collected and returned to the user-end equipment (51) for cooling. After heat exchange, the refrigerant enters the second seawater heat exchanger (33) and dissipates heat with the seawater driven by the seawater pump (45) and diverted into the second seawater heat exchanger (33) by the three-way valve (47). The temperature acquisition module is used to acquire in real time the coolant temperature t1 output by the direct heat exchange branch of seawater, the total supply temperature t2 after being collected and returned to the user terminal equipment (51), the coolant temperature t3 output by the seawater pump-driven heat exchange branch, and the coolant temperature t4 output by the seawater compression refrigeration heat exchange branch. The controller is used to control the start / stop status of each heat exchange branch to perform individual or coupled heat exchange modes based on the cooling demand temperature of the user terminal equipment (51), and to control the opening degree of three-way valve one (21) and three-way valve two (47) according to the supply liquid temperature difference of each heat exchange branch, so as to adjust the coolant diversion ratio and seawater diversion ratio in each heat exchange branch; the controller is also used to set an incremental temperature threshold of one to five according to the cooling demand temperature of the user terminal equipment (51), and make the following control decisions in combination with the real-time temperature value: When t2 is greater than temperature threshold one and less than temperature threshold two, the coolant pump (19) is controlled to operate, and the opening of the three-way valve (21) flowing to the flat plate heat exchanger (11) is adjusted to x%. So that coolant passes through each heat exchange branch, and the seawater pump (45) and the vapor compression refrigeration equipment are both in a stopped state; When t2 is not less than temperature threshold two and less than temperature threshold three, control the operation of the coolant pump (19), adjust the opening of the three-way valve one (21) to the plate heat exchanger (11) to 100%, and the opening of the valve to the seawater heat exchanger two (33) to 0. The seawater pump (45) and the vapor compression refrigeration equipment are both in a shutdown state. When t2 is not less than temperature threshold three and less than temperature threshold four, control the operation of coolant pump (19) and seawater pump (45), adjust the opening of three-way valve one (21) to the flat plate heat exchanger (11) to x%, so that coolant passes through each heat exchange branch, adjust the opening of three-way valve two (47) to the seawater heat exchanger one (22) to 100%, and the vapor compression refrigeration equipment is in a shutdown state; at this time, determine whether t1 is greater than t3. If it is, increase the opening of three-way valve one (21) to the seawater heat exchanger one (22) to increase the coolant flow rate of its heat exchange branch and downstream heat exchange branch, otherwise decrease it. When t2 is not less than temperature threshold 4 and less than temperature threshold 5, control the operation of coolant pump (19), seawater pump (45) and vapor compression refrigeration equipment; at this time, determine whether t1 is greater than t4. If so, increase the opening of three-way valve 1 (21) to seawater heat exchanger 1 (22) to increase the coolant flow rate of its heat exchange branch and downstream heat exchange branch, otherwise decrease it; at the same time, determine whether t3-t4 is less than a preset temperature difference threshold. If so, increase the opening of three-way valve 2 (47) to seawater heat exchanger 2 (33) to increase its seawater flow rate, otherwise decrease it.

2. The marine multi-mode cooling system according to claim 1, characterized in that, The cooling requirement of the user terminal device (51) has a lower limit of T1 and an upper limit of T2; wherein, the first temperature threshold is T1, the second temperature threshold is T1+3℃, the third temperature threshold is T2-5℃, the fourth temperature threshold is T2-3℃, and the fifth temperature threshold is T2-1℃; the temperature difference threshold is 3℃.

3. The marine multi-mode cooling system according to claim 1, characterized in that, The temperature acquisition module includes temperature transmitter one (12), temperature transmitter two (17), temperature transmitter three (23) and temperature transmitter four (35), which are used to acquire t1, t2, t3 and t4 in sequence. The direct seawater heat exchange branch also includes check valve one (13), liquid storage tank (14), shut-off valve two (18) and check valve two (110); the coolant output end of the plate heat exchanger (11) is connected to the liquid storage tank (14) through a pipe, and temperature transmitter one (12) and check valve one (13) are sequentially installed on this section of pipe; the output end of the liquid storage tank (14) is sequentially connected to temperature transmitter two (17), shut-off valve two (18), coolant pump (19) and check valve two (110) through a pipe, and finally connected to the coolant input end of the user terminal equipment (51); the coolant output end of the user terminal equipment (51) is connected to the inlet of three-way valve one (21), and the two outlets of three-way valve one (21) are respectively connected to the coolant input ends of the plate heat exchanger (11) and the seawater heat exchanger one (22); The seawater compression refrigeration heat exchange branch also includes check valve four (36); the coolant output end of seawater heat exchanger one (22) is connected to the coolant input end of evaporator (31) through a pipe, and temperature transmitter three (23) is installed on this section of pipe; the coolant output end of evaporator (31) is connected to the water storage tank through a pipe, and temperature transmitter four (35) and check valve four (36) are installed on this section of pipe in sequence.

4. A marine multi-mode cooling system according to claim 3, characterized in that, The seawater pump-driven heat exchange branch also includes stop valve four (44), check valve five (46), check valve six (48) and check valve seven (49); the input end of stop valve four (44) is connected to the seawater inlet, and the output end of stop valve four (44) is connected to the inlet of seawater pump (45), check valve five (46) and three-way valve two (47) in sequence through pipes. The two outlets of three-way valve two (47) are respectively connected to the seawater input ends of seawater heat exchanger one (22) and seawater heat exchanger two (33); the seawater output end of seawater heat exchanger one (22) is connected to the seawater outlet through pipes, and check valve six (48) is installed on this section of pipe; the seawater output end of seawater heat exchanger two (33) is connected to the seawater outlet through pipes, and check valve seven (49) is installed on this section of pipe.

5. A marine multi-mode cooling system according to claim 4, characterized in that, Between the seawater inlet and the four shut-off valves (44), a coarse filter (41), a coarse filter (42), and a fine filter (43) are installed in sequence along the seawater transmission direction. The filtration accuracies of the three filters are 3mm, 0.5mm, and 0.1mm, respectively.

6. A marine multi-mode cooling system according to claim 3, characterized in that, The direct seawater heat exchange branch also includes an expansion tank (15), a stop valve one (16), a stop valve three (111), a coolant standby pump (112), and a check valve three (113); the input end of the expansion tank (15) is connected to one end of the stop valve one (16), and the other end of the stop valve one (16) is connected in parallel to the pipeline between the liquid storage tank (14) and the temperature transmitter two (17); the stop valve three (111), the coolant standby pump (112), and the check valve three (113) are connected in sequence to form a standby flow path connected in parallel between the temperature transmitter two (17) and the coolant input end of the user terminal equipment (51).

7. A marine multi-mode cooling system according to claim 1, characterized in that, The vapor compression refrigeration equipment includes a throttling device (34) and a compressor (32); the input end of the throttling device (34) is connected to the refrigerant output end of the second seawater heat exchanger (33), the output end of the throttling device (34) is connected to the refrigerant input end of the evaporator (31), the refrigerant output end of the evaporator (31) is connected to the input end of the compressor (32), and the output end of the compressor (32) is connected to the refrigerant input end of the second seawater heat exchanger (33).

8. A marine multi-mode cooling system according to claim 1, characterized in that, The controller is also used to calculate the heat load change rate ΔQ / Δt of the cooling system in real time. The heat load ΔQ of the cooling system is positively correlated with the total power P of the user terminal equipment (51), and makes the following decisions: If the rate of change of heat load is less than a preset rate of change threshold, then control the coolant pump (19) to maintain at the initial speed V. c0 ; If the rate of change of heat load is not less than the rate of change threshold one and less than a preset rate of change threshold two, then control the coolant pump (19) to increase linearly; If the rate of change of heat load is not less than the rate of change threshold 2, then control the coolant pump (19) to step increase speed to rated speed V. c1 ; Among them, V c0 :V c1 =1:1.1~1.

2.

9. A marine multi-mode cooling system according to claim 1, characterized in that, The controller is also used to acquire the seawater temperature at the seawater inlet in real time and make the following decisions: If the seawater temperature is not higher than a preset temperature threshold a, then control the seawater pump (45) to maintain at the initial speed V. s0 ; If the seawater temperature is higher than temperature threshold a but not higher than a preset temperature threshold b, then the speed of the seawater pump (45) is dynamically increased or decreased within ±15%. If the seawater temperature is higher than the temperature threshold b but not higher than a preset temperature threshold c, then the seawater pump (45) is linearly accelerated according to the seawater temperature. If the seawater temperature is higher than the temperature threshold c, then control the seawater pump (45) to lock at the rated speed V. s1 ; Among them, V s0 :V s1 =1:1.1~1.3; a<b<c.

Images