JP7189065B2 - Cooling system for underwater vehicles - Google Patents

Description

The present invention relates to a cooling system mounted on an underwater vehicle.

2. Description of the Related Art Conventionally, there has been known a technique of using seawater to cool a heating element (for example, electronic equipment such as a battery, an inverter, and a server) mounted on an underwater vehicle. FIG. 3 is a block diagram showing an example of a conventional cooling system 102 mounted on an underwater vehicle 101. As shown in FIG. As shown in FIG. 3, the conventional underwater vehicle 101 includes a refrigerator 81 that uses seawater and an FCU 85 (fan coil unit) that uses the cold water generated by the refrigerator 81 to send out cold air. Prepare for. The cold air sent from the FCU 85 air-cools the heating element 20A arranged inside the pressure-resistant shell 10 . The refrigerator 81 has a seawater flow path 82 , a cold water circuit 84 , and a refrigeration circuit 83 that mediates heat exchange between the seawater flow path 82 and the cold water circuit 84 .

Patent Literature 1 discloses a submarine equipped with a refrigeration system that utilizes seawater as described above. The refrigeration system comprises a refrigeration circuit including a condenser located inside the hull, and a closed circuit including a lid of the condenser and a cooler located outside the hull. The cooling fluid circulating in the closed circuit by natural circulation or forced circulation is cooled with sea water in the cooler and exchanges heat with the refrigerant circulating in the refrigeration circuit at the water lid of the condenser. In this refrigeration system, the condenser is indirectly cooled by seawater.

Japanese Utility Model Laid-Open No. 56-168494

As the performance of electronic devices (eg, batteries, inverters, servers, etc.) installed in underwater vehicles increases, the heat load inside the underwater vehicle is expected to increase. In order to cope with the increase in heat load, it is required to further improve the cooling capacity of the cooling system mounted on the underwater vehicle. However, for example, when improving the cooling capacity in the conventional cooling system shown in FIG. An increase in the size of the blower of the FCU 85, etc., entails an increase in the size of the entire system and an increase in energy consumption.

The present invention has been made in view of the above circumstances, and its object is to propose a technique for improving the cooling capacity of a cooling system mounted on an underwater vehicle while suppressing an increase in the size of the system. .

An underwater vehicle cooling system according to one aspect of the present invention comprises:
an immersion tank arranged inside a pressure hull of an underwater vehicle, an external heat exchanger arranged outside the pressure hull, a forward pipe connecting a tank outlet of the immersion tank and an inlet of the external heat exchanger, and a closed refrigerant circulation path having a return pipe connecting an outlet of the external heat exchanger and an inlet of the liquid immersion tank, wherein a heating element is immersed in the refrigerant in the liquid immersion tank to heat the external heat. The heat generating element is cooled by heat exchange between the refrigerant and the water around the pressure shell in the exchanger.

According to the underwater vehicle cooling system configured as described above, the heating element is cooled by a liquid osmosis liquid cooling system in which the heating element is immersed in the refrigerant, and the refrigerant directly exchanges heat with the water surrounding the pressure shell. Since the liquid-phase refrigerant is in direct contact with the heating element to remove heat, the cooling capacity is significantly improved compared to the conventional air cooling system. In addition, by improving the cooling capacity, it is possible to increase the installation density of the heating elements, thereby suppressing an increase in the size of the system.

ADVANTAGE OF THE INVENTION According to this invention, in the cooling system mounted in an underwater vehicle, the technique of improving a cooling capacity can be proposed, suppressing the enlargement of a system.

FIG. 1 is a block diagram showing the overall configuration of a cooling system mounted on an underwater vehicle according to one embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the control system of the cooling system. FIG. 3 is a block diagram showing the overall configuration of a cooling system mounted on a conventional underwater vehicle.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a cooling system 2 mounted on an underwater vehicle 1 according to one embodiment of the present invention.

An underwater vehicle 1 shown in FIG. 1 has a pressure hull 10 for sailing in and on water and for withstanding water pressure. Hereinafter, the inside of the pressure hull 10 will be referred to as "vehicle interior 11", and the exterior of the pressure hull 10 will be referred to as "vehicle exterior 12". When the pressure-resistant shell 10 is composed of two layers, an outer shell of a non-pressure-resistant structure and an inner shell of a pressure-resistant structure, the vehicle interior 11 represents the inside of the inner shell, and the vehicle exterior 12 represents the exterior of the inner shell (inner shell). and the outer shell).

A cooling system 2 mounted on an underwater vehicle 1 comprises a liquid immersion bath 21 provided within the vehicle 11 . A coolant 22 is filled in the liquid immersion tank 21 . The coolant in the liquid immersion tank 21 is in a liquid phase in the lower part of the tank and in a gas-liquid two-phase (or vapor phase) in the upper part of the tank. The entire heating element 20 is submerged in the liquid-phase coolant 22 . As the coolant 22, an inert liquid is used in which an electronic device including a power supply can be immersed and operated.

An external heat exchanger 31 is provided outside the vehicle 12 . A bath outlet 21 a provided at the top of the liquid immersion bath 21 and an inlet of the external heat exchanger 31 are connected by a forward pipe 41 . A bath inlet 21 b provided at the bottom of the liquid immersion bath 21 and an outlet of the external heat exchanger 31 are connected by a return pipe 42 . In the posture in which the underwater vehicle 1 is sailing at a constant depth, the posture in which the underwater vehicle 1 is sailing on water, and the posture in which the underwater vehicle 1 is stationary, the outbound pipe 41 is higher than the return pipe 42. To position.

By connecting the liquid immersion tank 21 and the external heat exchanger 31 with an outward pipe 41 and a return pipe 42, a sealed refrigerant circuit 4 including the liquid immersion tank 21 and the external heat exchanger 31 is formed. there is The inside of the refrigerant circuit 4 is at atmospheric pressure, or is pressure-reduced below atmospheric pressure. The degree of vacuum in the refrigerant circuit 4 may be adjusted so that the refrigerant 22 undergoes a phase change within the refrigerant system. By utilizing the latent heat generated by the phase change of the refrigerant 22, the heat transport efficiency within the refrigerant system can be further improved.

The external heat exchanger 31 cools the refrigerant 22 by exchanging heat between the water around the pressure shell 10 and the refrigerant 22 flowing through the refrigerant circuit 4 . In this embodiment, the underwater vehicle 1 travels in the sea, and the water around the pressure hull 10 is seawater. However, when the underwater vehicle 1 travels through lakes and marshes, the water around the pressure hull 10 is fresh water.

A tank outlet 21 a of the liquid immersion tank 21 is provided with an in-tank channel switching valve 23 . An upper outlet 24 that is an outlet for the gas-liquid two-phase or gas-phase coolant 22 is provided at the upper portion of the liquid immersion bath 21 . The upper outlet 24 is connected to the in-tank flow path switching valve 23 via a pipe or the like. In addition, a lower outlet 25 that is an outlet for the liquid-phase coolant 22 is provided at the lower portion of the liquid immersion tank 21 . The lower outlet 25 and the in-tank flow path switching valve 23 are connected by a liquid lifting pipe 26 , and the liquid lifting pipe 26 is provided with a liquid lifting pump 27 for pumping the refrigerant 22 .

Under the control of the control device 7 provided in the vehicle 11, the in-tank flow path switching valve 23 switches between a first state in which the tank outlet 21a and the upper outlet 24 are connected, and a state in which the tank outlet 21a and the lower outlet 25 are connected. is connected to the second state.

A first on-off valve 43 is provided in the outward pipe 41 immediately upstream of the external heat exchanger 31 . A second opening/closing valve 44 is provided in the return pipe 42 immediately downstream of the external heat exchanger 31 . The refrigerant 22 flows to the external heat exchanger 31 when the first on-off valve 43 and the second on-off valve 44 are opened. The refrigerant 22 does not flow to the external heat exchanger 31 when the first on-off valve 43 and the second on-off valve 44 are closed. The first on-off valve 43 and the second on-off valve 44 are controlled by the control device 7 to switch between opening and closing of the valves.

A fire extinguishing flow path 55 is connected to the outward pipe 41 . A fire extinguishing on-off valve 56 is provided in the fire extinguishing passage 55 . When a fire breaks out in the vehicle 11, the fire extinguishing on-off valve 56 is opened to send the refrigerant 22 to the fire site, and the refrigerant 22 is used for extinguishing the fire.

An upstream end and a downstream end of a forced circulation path 48 are connected downstream of the connecting portion of the return pipe 42 with the internal heat exchange path 5 . A refrigerant pump 47 that pressure-feeds the refrigerant 22 is provided in the forced circulation path 48 . A passage switching valve 46 is provided at the connecting portion between the return pipe 42 and the upstream end of the forced circulation passage 48 . Under the control of the control device 7, the flow path switching valve 46 is in a first state in which the refrigerant 22 flowing through the return pipe 42 is not allowed to flow through the forced circulation path 48, and in which the refrigerant 22 flowing through the return pipe 42 is allowed to flow through the forced circulation path 48. Selectively switch to the second state. A forced circulation system in which the refrigerant 22 flowing through the refrigerant circulation path 4 passes through the forced circulation path 48 and a natural circulation system in which the refrigerant 22 flowing through the refrigerant circulation path 4 does not pass through the forced circulation path 48 are switched by switching the flow path switching valve 46. is switched.

The refrigerant circulation path 4 is connected to an internal heat exchange path 5 that allows the refrigerant 22 flowing through the outward pipe 41 to flow to the return pipe 42 without passing through the external heat exchanger 31 . The upstream end of the internal heat exchange path 5 is connected to the outward pipe 41 , and the downstream end of the internal heat exchange path 5 is connected to the return pipe 42 . A flow rate control valve 51 is provided at the connection between the upstream end of the internal heat exchange path 5 and the outgoing line pipe 41 . The flow regulating valve 51 is controlled by the control device 7 and adjusts the flow rate of the refrigerant flowing to the internal heat exchange passage 5 by changing the degree of opening within the range of 0 to 100%.

An internal heat exchanger 6 is provided in the internal heat exchange path 5 . An internal heat exchanger 6 is provided within the vehicle 11 . The internal heat exchanger 6 cools the refrigerant 22 by exchanging heat between the cold water flowing through the cold water circuit 84 and the refrigerant 22 . The chilled water flowing through the chilled water circuit 84 is cooled by the refrigerator 81 provided inside the vehicle 11 .

A refrigerator 81 that uses seawater and an FCU 85 (fan coil unit) that uses the cold water generated by the refrigerator 81 to send out cold air are provided inside the pressure shell 10 . The cold air sent from the FCU 85 air-cools the heating element 20A arranged inside the pressure-resistant shell 10 . The refrigerator 81 has a seawater flow path 82 , a cold water circuit 84 , and a refrigeration circuit 83 that mediates heat exchange between the seawater flow path 82 and the cold water circuit 84 . The seawater flow path 82 is provided with a seawater pump 86 that pumps seawater. The cold water circuit 84 is provided with a cold water pump 87 for forcibly circulating cold water.

Seawater is taken into the seawater channel 82 from the outside 12 of the vehicle. In the refrigerator 81 , the refrigerant is cooled by heat exchange between the seawater flowing through the seawater channel 82 and the refrigerant flowing through the refrigerating circuit 83 . The warmed seawater is discharged outside the vehicle 12 . Also, in the refrigerator 81 , cold water is cooled by heat exchange between the cooled refrigerant and the cold water flowing through the cold water circuit 84 . That is, the refrigerator 81 indirectly cools the cold water flowing through the cold water circuit 84 using seawater. The chilled water circuit 84 may flow through an FCU (fan coil unit) 85 provided inside the vehicle 11 in addition to the internal heat exchanger 6 . The cold air sent out from the FCU 85 cools the heating element 20A arranged inside the vehicle 11 .

FIG. 2 is a diagram showing the configuration of the control system of the cooling system 2. As shown in FIG. As shown in FIGS. 1 and 2, a thermometer 75 and a flow meter 76 are electrically connected to the control device 7 by wire or wirelessly, and their detection values are obtained. A thermometer 75 is provided on the return pipe 42 and detects a circulating refrigerant temperature T, which is the temperature of the refrigerant 22 flowing into the liquid immersion bath 21 . In this embodiment, the thermometer 75 is provided immediately upstream of the flow path switching valve 46 in the return pipe 42 . A flow meter 76 is provided in the return pipe 42 and detects a circulating refrigerant amount F, which is the flow rate of the refrigerant 22 flowing into the liquid immersion bath 21 . In this embodiment, the flow meter 76 is provided in the return pipe 42 immediately upstream of the bath inlet 21 b of the liquid immersion bath 21 .

The control device 7 is electrically connected to the in-tank channel switching valve 23, the flow control valve 51, the channel switching valve 46, the first on-off valve 43, and the second on-off valve 44, and controls these valves. control behavior. The control device 7 controls the operation of the first valve control section 71 that controls the operation of the flow rate adjustment valve 51, the second valve control section 72 that controls the operation of the flow path switching valve 46, and the in-tank flow path switching valve 23. A function as the third valve control section 73 is included. The control device 7 is also electrically connected to the liquid pump 27 and the refrigerant pump 47 and controls the operations of these pumps.

The control device 7 is a so-called computer, and includes, for example, an arithmetic processing device (processor) such as a microcontroller, CPU, MPU, PLC, DSP, ASIC, or FPGA, and volatile and nonvolatile storage devices such as ROM and RAM. and (neither shown). The storage device stores programs executed by the arithmetic processing unit, various fixed data, and the like. In the control device, processing for operating the cooling system 2 is performed by the arithmetic processing device reading and executing software such as a program stored in the storage device. Operation control of the cooling system 2 by the controller 7 will be described below.

[Regular operation]
First, steady operation of the cooling system 2 will be described. In steady operation, the first on-off valve 43 and the second on-off valve 44 are opened and the refrigerant 22 flows through the external heat exchanger 31 . The in-tank flow path switching valve 23 is in the first state in which the upper outlet 24 is connected to the outgoing line pipe 41 via the tank outlet 21a. The flow control valve 51 is closed and the refrigerant 22 does not flow through the internal heat exchange passage 5 . The flow path switching valve 46 is in the first state in which the refrigerant 22 is not allowed to flow through the forced circulation path 48 .

In the cooling system 2 during steady operation, the liquid-phase coolant 22 heated by the heating element 20 in the liquid immersion bath 21 boils to generate bubbles. A gas-liquid two-phase or gas-phase refrigerant 22 flows out from the liquid immersion bath 21 to the forward pipe 41 through the upper outlet 24 . The vapor-phase refrigerant 22 that has flowed to the external heat exchanger 31 through the outward pipe 41 is cooled by seawater in the external heat exchanger 31 and condensed into a liquid phase. The liquid-phase refrigerant 22 flows out from the external heat exchanger 31 to the return pipe 42 and returns to the liquid immersion tank 21 from the tank inlet 21b. Thus, in the cooling system 2 during steady operation, the phase change of the refrigerant 22 causes a density difference in the refrigerant 22 , and the refrigerant 22 naturally circulates in the refrigerant circuit 4 . In other words, a two-phase natural circulation loop is formed in the cooling system 2 during steady operation.

The control device 7 constantly monitors the circulating refrigerant temperature T detected by the thermometer 75 and the circulating refrigerant amount F detected by the flow meter 76 . In this embodiment, the circulating refrigerant temperature T is detected by the thermometer 75, but the circulating refrigerant temperature T is indirectly detected based on the pressure of the refrigerant 22 detected by the pressure gauge and the flow rate of the refrigerant 22 detected by the flow meter. can be detected. In this embodiment, the circulating refrigerant amount F is detected by the flow meter 76, but the circulating refrigerant amount F is indirectly detected based on the temperature of the refrigerant 22 detected by the thermometer and the pressure of the refrigerant 22 detected by the pressure gauge. can be detected.

The seawater temperature around the pressure hull 10 changes with the depth of the underwater vehicle 1 . Due to such a change in seawater temperature, the heat exchange capacity of the external heat exchanger 31 fluctuates. In addition, the underwater vehicle 1 may travel not only underwater but also on water. When the external heat exchanger 31 is no longer immersed in seawater during cruising on water, the external heat exchanger 31 using seawater cannot be used. As described above, the heat exchange capacity of the external heat exchanger 31 may be reduced due to factors such as an increase in seawater temperature, failure of the external heat exchanger 31, and navigation on water. A decrease in the heat exchange capacity of the external heat exchanger 31 can be estimated based on the temperature T of the circulating refrigerant. Also, when the heat load of the heating element 20 increases, the natural circulation of the coolant 22 may lack the cooling capacity. Insufficient cooling capacity of the cooling system 2 can be estimated based on the amount F of the circulating refrigerant.

The controller 7 detects insufficient heat exchange capacity of the external heat exchanger 31 based on the circulating refrigerant temperature T, and controls the flow control valve 51 so that the refrigerant flows to the internal heat exchange path 5 . Further, the control device 7 detects insufficient cooling capacity for the heat load of the heating element 20 based on the circulating refrigerant amount F, and controls the flow switching valve 46 so that the refrigerant flows to the forced circulation path 48 . The control device 7 switches the operation method according to the detected combination of the circulating refrigerant temperature T and the circulating refrigerant amount F, as described below.

As shown in Table 1, when the circulating refrigerant temperature T is equal to or lower than a predetermined temperature threshold value T0 and the circulating refrigerant amount F is equal to or higher than a predetermined flow rate threshold value F0, the controller 7 causes the cooling system 2 to operate steadily. I do. When the circulating refrigerant temperature T exceeds the temperature threshold value T0 and the circulating refrigerant amount F is equal to or greater than the flow rate threshold value F0, the control device 7 performs the “heat exchange combined operation” of the cooling system 2 . When the circulating refrigerant temperature T is equal to or less than the temperature threshold value T0 and the circulating refrigerant amount F is less than the flow rate threshold value F0, the control device 7 performs the “forced circulation operation” of the cooling system 2 . When the circulating refrigerant temperature T exceeds the temperature threshold value T0 and the circulating refrigerant amount F is less than the flow rate threshold value F0, the control device 7 performs the “forced circulation/heat exchange combined operation” of the cooling system 2 .

[Combined operation with heat exchanger]
In the cooling system 2 of combined heat exchange operation, the first on-off valve 43 and the second on-off valve 44 are opened, and the refrigerant 22 flows through the external heat exchanger 31 . The in-tank flow path switching valve 23 is in the first state, and the upper outlet 24 is connected to the outgoing line pipe 41 via the tank outlet 21a. The flow control valve 51 is open and the refrigerant 22 flows through the internal heat exchange passage 5 . The flow rate of the refrigerant 22 flowing through the internal heat exchange path 5 may be adjusted by the flow rate adjustment valve 51 . The flow switching valve 46 is in the first state and the refrigerant 22 does not flow through the forced circulation path 48 .

In the cooling system 2 for combined heat exchange operation, the liquid-phase coolant 22 heated by the heating element 20 in the liquid immersion bath 21 evaporates into two gas-liquid phases (or gas phase), and passes through the upper outlet 24 to the liquid immersion bath 21 . flows out to the outbound pipe 41 from the A portion of the refrigerant 22 that has flowed out to the outward pipe 41 is cooled by seawater in the external heat exchanger 31 , condensed into a liquid phase, and flows into the return pipe 42 . The rest of the refrigerant 22 that has flowed out to the forward pipe 41 passes through the internal heat exchange passage 5 and is cooled by the cold water in the internal heat exchanger 6 , condenses into a liquid phase, and flows into the return pipe 42 . The refrigerant 22 that has flowed into the return pipe 42 returns to the liquid immersion tank 21 from the tank inlet 21b. As described above, in the cooling system 2 of combined heat exchange operation, the phase change of the refrigerant 22 allows the refrigerant 22 to naturally circulate through the refrigerant circuit 4 including the internal heat exchange passage 5 .

In the combined heat exchange operation, in principle, both the external heat exchanger 31 and the internal heat exchanger 6 are used, but only the internal heat exchanger 6 may be used. In this case, the first on-off valve 43 and the second on-off valve 44 are closed in the cooling system 2 in the combined heat exchange operation.

[Forced circulation operation]
In the forced circulation cooling system 2 , the first on-off valve 43 and the second on-off valve 44 are opened, and the refrigerant 22 flows through the external heat exchanger 31 . The in-tank flow path switching valve 23 is in the first state, and the upper outlet 24 is connected to the outgoing line pipe 41 via the tank outlet 21a. The flow control valve 51 is closed and the refrigerant 22 does not flow through the internal heat exchange passage 5 . The flow switching valve 46 is in the second state, the refrigerant pump 47 is operated, and the refrigerant 22 flows through the forced circulation path 48 .

In the forced circulation cooling system 2 , the liquid-phase coolant 22 heated by the heating element 20 in the liquid immersion bath 21 evaporates into a gas phase, and the gas-liquid two-phase (or gas-phase) coolant 22 exits the upper outlet 24 . It flows out from the liquid immersion tank 21 to the outbound pipe 41 through the The refrigerant 22 that has flowed out to the outward pipe 41 is cooled by seawater in the external heat exchanger 31 , condensed into a liquid phase, and flows into the return pipe 42 . The coolant 22 that has flowed into the return pipe 42 returns to the liquid immersion tank 21 via the forced circulation path 48 from the tank inlet 21b. As described above, in the cooling system 2 of the combined heat exchange operation, the coolant 22 is forcibly circulated by operating the coolant pump 47 .

In the forced circulation cooling system 2, the liquid-phase (or gas-liquid two-phase) refrigerant 22 may be circulated. In this case, in the forced circulation cooling system 2, the in-tank flow path switching valve 23 is in the second state, the lower outlet 25 is connected to the forward pipe 41 via the tank outlet 21a, and the liquid pump 27 is in operation. be done.

In the forced circulation cooling system 2 , the liquid-phase coolant 22 heated by the heating element 20 in the liquid immersion tank 21 is pressure-fed from the liquid immersion tank 21 to the forward pipe 41 through the lower outlet 25 . The refrigerant 22 that has flowed out to the outbound pipe 41 is cooled by seawater in the external heat exchanger 31 and flows into the inbound pipe 42 . The coolant 22 that has flowed into the return pipe 42 returns to the liquid immersion tank 21 via the forced circulation path 48 from the tank inlet 21b. As described above, in the cooling system 2 of combined heat exchange operation, the liquid-phase (or gas-liquid two-phase) refrigerant 22 is forcibly circulated by operating the liquid pump 27 and the refrigerant pump 47 .

[Combined forced circulation and heat exchange operation]
In the forced circulation/heat exchange combined operation cooling system 2 , the first on-off valve 43 and the second on-off valve 44 are opened, and the refrigerant 22 flows through the external heat exchanger 31 . The in-tank flow path switching valve 23 is in the second state, the lower outlet 25 is connected to the forward line pipe 41 via the tank outlet 21a, and the pump 27 is operated. The flow control valve 51 is open and the refrigerant 22 flows through the internal heat exchange path 5 and the internal heat exchanger 6 . The flow rate of the refrigerant 22 flowing through the internal heat exchange path 5 may be adjusted by the flow rate adjustment valve 51 . The flow switching valve 46 is in the second state, the refrigerant pump 47 is operated, and the refrigerant 22 flows through the forced circulation path 48 .

In the forced circulation/heat exchange combined operation cooling system 2, the liquid-phase (or gas-liquid two-phase) refrigerant 22 warmed by the heating element 20 in the liquid immersion tank 21 flows out of the liquid immersion tank 21 through the lower outlet 25. It is pumped into tube 41 . A portion of the refrigerant 22 that has flowed out to the outward pipe 41 is cooled by seawater in the external heat exchanger 31 and flows into the return pipe 42 . The rest of the refrigerant 22 flowing out to the outward pipe 41 passes through the internal heat exchange passage 5 and is cooled by cold water in the internal heat exchanger 6 and flows into the return pipe 42 . The coolant 22 that has flowed into the return pipe 42 returns to the liquid immersion tank 21 via the forced circulation path 48 from the tank inlet 21b. Thus, in the forced circulation/heat exchange combined operation cooling system 2 , the liquid-phase (or gas-liquid two-phase) refrigerant 22 is forcibly circulated by operating the liquid pump 27 and the refrigerant pump 47 . Moreover, in the forced circulation/heat exchange combined operation cooling system 2 , both the external heat exchanger 31 and the internal heat exchanger 6 are used to cool the refrigerant 22 . As a result, in the forced circulation/heat exchange combined operation cooling system 2, the cooling capacity of the cooling system 2 is greatly amplified as compared to that during steady operation.

As described above, the underwater vehicle cooling system 2 according to the present embodiment includes the liquid immersion tank 21 arranged inside the pressure hull 10 of the underwater vehicle 1, and the external heat exchange device arranged outside the pressure hull 10. vessel 31, an outbound pipe 41 connecting the bath outlet 21a of the liquid immersion bath 21 and the inlet of the external heat exchanger 31, and a return pipe connecting the outlet of the external heat exchanger 31 and the bath inlet 21b of the liquid immersion bath 21. A closed refrigerant circuit 4 with 42 is provided. Then, the heating element 20 is immersed in the refrigerant 22 in the liquid immersion tank 21, and heat is exchanged between the refrigerant 22 and the water surrounding the pressure shell 10 in the external heat exchanger 31, thereby cooling the heating element 20. .

According to the underwater vehicle cooling system 2 configured as described above, the heating element 20 is cooled by the liquid immersion liquid cooling method in which the cooling medium is immersed in the cooling medium 22, and the cooling medium 22 directly exchanges heat with the water around the pressure shell 10. . Since the liquid-phase coolant 22 is in direct contact with the heating element to remove heat, the cooling capacity is significantly improved compared to the conventional air cooling system. In addition, by improving the cooling capacity, it is possible to increase the installation density of the heating elements 20, thereby suppressing an increase in the size of the system. In addition, the cooling system 2 is quieter than an air-cooled system, and is suitable for cooling the heating element 20 inside the vehicle 11, which is a closed space.

Further, the underwater vehicle 1 according to this embodiment includes an internal heat exchanger 6 arranged inside the pressure shell 10 , and the upstream end and the downstream end are connected to the refrigerant circuit 4 . and an internal heat exchange passage 5 through which the refrigerant flows;

As a result, when the heat exchange capacity of the external heat exchanger 31 is lowered, the external heat exchanger 31 and the internal heat exchange path 5 are used together, or the heat exchanger is changed from the external heat exchanger 31 to the internal heat exchange path 5. By switching to , the cooling performance of the cooling system 2 can be maintained.

In the above, the internal heat exchange path 5 may bypass the external heat exchanger 31 and allow the refrigerant 22 to flow from the outbound pipe 41 to the inbound pipe 42 through the internal heat exchanger 6 .

As a result, when the heat exchange capacity of the external heat exchanger 31 is lowered, the heat exchanger for cooling the refrigerant 22 is switched from the external heat exchanger 31 to the internal heat exchange path 5 to improve the cooling performance of the cooling system 2. can be maintained.

The cooling system 2 includes a first detector (for example, a thermometer 75) that detects the circulating refrigerant temperature T of the refrigerant circuit 4, and a lack of heat exchange capacity of the external heat exchanger 31 based on the circulating refrigerant temperature T. A first valve control unit 71 that detects and controls the flow control valve 51 so that the refrigerant flows to the internal heat exchange path 5 may be further provided.

As a result, when the heat exchange capacity of the external heat exchanger 31 is reduced, the refrigerant 22 is automatically switched to flow through the internal heat exchange path 5, and the reduction in heat exchange capacity can be compensated for.

In addition, the cooling system 2 according to the present embodiment includes a refrigerant pump 47 that pumps the refrigerant 22, a forced circulation path 48 whose upstream end and downstream end are connected to the refrigerant circulation path 4, and an upstream end of the forced circulation path 48. and a flow path switching valve 46 provided at a connecting portion with the refrigerant circulation path 4 .

As a result, when the cooling capacity of the cooling system 2 is insufficient, the coolant 22 can be forcibly circulated to increase the cooling capacity.

The cooling system 2 includes a second detector (for example, a flow meter 76) that detects the amount F of the circulating refrigerant in the refrigerant circuit 4, and a lack of cooling capacity for the heat load of the heating element 20 based on the amount F of the circulating refrigerant. A second valve control unit 72 that detects and controls the flow path switching valve 46 so that the refrigerant flows to the forced circulation path 48 may further be provided.

As a result, when the cooling capacity of the cooling system 2 is insufficient, the coolant 22 can be automatically circulated forcibly to increase the cooling capacity.

Further, in the cooling system 2 according to the present embodiment, the liquid immersion bath 21 has an upper outlet 24 provided in the upper part of the bath, a lower outlet 25 provided in the lower part of the bath, and an upper outlet 24 and a lower outlet 25. It further has an in-bath channel switching valve 23 selectively connected to the tank outlet 21 a of the liquid immersion tank 21 .

As a result, a state (first state) in which the gas-phase refrigerant 22 flows out from the refrigerant circulation path 4 to the forward pipe 41 and a state (second state) in which the liquid-phase (or gas-liquid two-phase) refrigerant 22 flows out. can be switched between In the first state, the refrigerant 22 naturally circulates through the refrigerant circulation path 4 by utilizing the phase change of the refrigerant 22, so energy for forcibly circulating the refrigerant 22 is not required. Further, in the second state, the liquid-phase (or gas-liquid two-phase) refrigerant 22 can be circulated in the refrigerant circulation path 4, so that the cooling capacity of the cooling system 2 can be further enhanced.

Although the preferred embodiments of the present invention have been described above, the present invention may include modifications of the details of the specific structures and/or functions of the above embodiments without departing from the spirit of the present invention. .

1: Underwater vehicle 2: Cooling system 4: Circulation path 5: Internal heat exchange path 6: Internal heat exchanger 7: Control device 10: Pressure shell 11: Inside vehicle 12: Outside vehicle 20, 20A: Heating element 21: Liquid immersion Tank 21a : Tank outlet 21b : Tank inlet 22 : Refrigerant 23 : In-tank channel switching valve 24 : Upper outlet 25 : Lower outlet 26 : Liquid lifting pipe 27 : Liquid lifting pump 31 : External heat exchanger 41 : Forward pipe 42 : Return pipe 43 : First on-off valve 44 : Second on-off valve 46 : Flow path switching valve 47 : Refrigerant pump 48 : Forced circulation path 51 : Flow control valve 55 : Fire extinguishing flow path 56 : Fire extinguishing on-off valve 71 : Arithmetic processing unit 72 : Storage device 75 : Thermometer 76 : Flow meter 81 : Refrigerator 82 : Seawater flow path 83 : Refrigeration circuit 84 : Chilled water circuit 85 : FCU
86: Sea water pump 87: Cold water pump F: Circulating refrigerant amount F0: Flow rate threshold T: Circulating refrigerant temperature T0: Temperature threshold

Claims (7)

An immersion tank arranged inside a pressure hull of an underwater vehicle, an external heat exchanger arranged outside the pressure hull, and an outbound pipe connecting a tank outlet of the immersion tank and an inlet of the external heat exchanger. and a closed refrigerant circuit having a return pipe connecting the outlet of the external heat exchanger and the inlet of the liquid immersion bath,
A heating element is immersed in the refrigerant in the liquid immersion tank, and the external heat exchanger exchanges heat between the refrigerant and water around the pressure shell, thereby cooling the heating element.
Cooling system for underwater vehicles. an internal heat exchange passage comprising an internal heat exchanger located inside the pressure shell, having upstream and downstream ends connected to the refrigerant circuit, and flowing the refrigerant through the internal heat exchanger;
further comprising a flow control valve provided at a connection portion between the refrigerant circulation path and the internal heat exchange path;
A cooling system for an underwater vehicle according to claim 1. The internal heat exchange path bypasses the external heat exchanger and flows the refrigerant from the outbound pipe through the internal heat exchanger to the return pipe,
A cooling system for an underwater vehicle according to claim 2. a first detector that detects the temperature of the circulating refrigerant in the refrigerant circuit;
a first valve control unit that detects an insufficient heat exchange capacity of the external heat exchanger based on the temperature of the circulating refrigerant and controls the flow control valve so that the refrigerant flows into the internal heat exchange path; prepare
A cooling system for an underwater vehicle according to any one of claims 2-3. a forced circulation path including a refrigerant pump for pumping the refrigerant, the upstream end and the downstream end of which are connected to the refrigerant circulation path;
further comprising a flow path switching valve provided at a connection portion between the upstream end of the forced circulation path and the refrigerant circulation path;
A cooling system for an underwater vehicle according to any one of claims 1-4. a second detector that detects the amount of circulating refrigerant in the refrigerant circuit;
a second valve control unit that detects a lack of cooling capacity for the heat load of the heating element based on the amount of circulating refrigerant and controls the flow path switching valve so that the refrigerant flows to the forced circulation path; prepare
A cooling system for an underwater vehicle according to claim 5. The liquid immersion bath has an upper outlet provided at an upper portion in the bath, a lower outlet provided at a lower portion in the bath, and selectively connecting the upper outlet and the lower outlet to the bath outlet of the liquid immersion bath. further comprising an in-tank flow path switching valve,
A cooling system for an underwater vehicle according to any one of claims 1-6.

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