Water-cooled submarine power unit
The water-cooled submarine power device employs natural convection through seawater-cooled channels to enhance cooling efficiency and reduce complexity and cost by eliminating the need for active cooling components.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- AKER SOLUTIONS AS
- Filing Date
- 2024-06-24
- Publication Date
- 2026-07-23
AI Technical Summary
Existing submarine power units require complex and expensive solutions for heat dissipation, often involving active cooling mechanisms like pumps and valves, and may not effectively utilize natural convection for cooling in seawater environments.
A water-cooled submarine power device with a liquid-filled enclosure and integrated cooling channels that utilize natural convection through density differences, allowing seawater to flow through channels connected to the housing for efficient heat dissipation without active cooling components.
Achieves improved cooling performance by leveraging natural convection and seawater temperature differences, eliminating the need for pumps and reducing equipment complexity and cost while maintaining effective heat management.
Smart Images
Figure 2026524611000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a water-cooled submarine power device configured to be installed in a water area such as the seabed.
Background Art
[0002] Many power units generate heat that must be dissipated from the power unit. Typical units include transformers, variable speed drives, rectifiers, or switching devices. When such power units are installed on the seabed, it is known to utilize the relatively low water temperature to cool the power units.
[0003] For example, some solutions connect the oil in a housing filled with oil to an external heat exchanger so that the oil is cooled by water. The cooled oil flows in a loop, exits the housing as warm oil, enters the heat exchanger, and returns to the housing as cooled oil.
[0004] This type of equipment is typically relatively complex and expensive because it includes a pump for providing the flow of oil and, in some cases, a valve for controlling the flow.
[0005] Publication EP3404198B1 presents a solution to avoid these drawbacks, which uses natural convection to provide the flow of the cooling fluid. The cooling fluid flows out of the housing containing the heat-generating electrical unit and enters an external pressure compensator. In the pressure compensator, the fluid is cooled and then flows back into the housing. Thus, in this solution, the pressure compensator must provide not only a cooling function (acting as a heat exchanger) but also a pressure compensation function.
[0006] When the heat generated inside the housing containing the heat-generating power unit is sufficiently low, it may be sufficient to provide the housing with cooling ribs or other protrusions that direct the generated heat to the surrounding seawater.
[0007] However, if this is insufficient, it is common practice to divert the fluid inside the enclosure, typically oil, out of the enclosure for external cooling. [Overview of the project] [Problems that the invention aims to solve]
[0008] One of the objectives of the present invention may be to provide a solution that avoids the need to allow fluid to flow out of the housing.
[0009] Another objective may be to provide a water-cooled submarine power unit with improved cooling performance while avoiding active cooling (i.e., using pumps to maintain fluid flow).
[0010] Further objectives may be satisfied by the present invention, as will become apparent from the following disclosures. [Means for solving the problem]
[0011] According to the present invention, a water-cooled submarine power device is configured, comprising a liquid-filled enclosure that encloses a heat-generating power unit, such as a submarine transformer, a VSD (variable speed drive), or another electrical heat-generating unit. The power device further comprises a plurality of cooling channels. The cooling channels extend through the enclosure and have inlets and outlets. The inlets are located vertically below the outlets. Furthermore, both the inlets and outlets of each cooling channel are in liquid communication with the surrounding seawater.
[0012] The liquid inside the enclosure may be oil or another dielectric liquid.
[0013] In this way, the surrounding cold seawater can flow through the cooling channel. As those skilled in the art will understand, the flow is generated by a decrease in density in the heated water inside the cooling channel.
[0014] A power unit is typically a high-power unit, meaning it is configured or rated to handle power greater than 5 MVA, or greater than 10 MVA, or even greater than 50 MVA.
[0015] In some embodiments, the housing may comprise a base plate and a top plate, and the entrance is located on the base plate.
[0016] However, in other embodiments, some or all of the entrances may be entrances located in the walls of the housing.
[0017] Furthermore, the housing may have vertical housing walls extending between the base plate and the top plate. The base plate and the top plate may extend horizontally beyond the housing walls. The housing may further comprise a plurality of ribs extending between the base plate and the top plate, the ribs in contact with the housing walls and extending outward from the housing walls. In such embodiments, the base plate and / or the top plate may have rib channel openings at each end of rib channels extending laterally between adjacent ribs.
[0018] In some embodiments, the outlets of the cooling channels are located on the top plate. In other embodiments, the outlets are located on the enclosure walls. Combinations are also possible in which some outlets are located on the top plate and others on the enclosure walls.
[0019] In some embodiments, the cooling channel may be linear. However, in other embodiments or combined embodiments, the cooling channel may comprise a vertical, linear lower portion, a curved portion connected to the upper part of the lower portion, and an end portion terminating at an outlet. As those skilled in the art will understand, these portions may be pipes.
[0020] In some such embodiments, the curved portion may have a bending angle in the range of 30 degrees to 50 degrees, for example, a bending angle of 45 degrees. In other embodiments, the curved portion may have a bending angle of substantially 90 degrees.
[0021] The cooling channel can advantageously be made of a pipe containing copper nickel (CuNi) (or cupronickel), i.e., an alloy containing copper and nickel.
[0022] The power unit can be, for example, a transformer, a switchgear, a variable speed drive, a rectifier, a frequency converter, or a current collector.
[0023] In some embodiments, the water-cooled submarine power device further comprises a funnel disposed around the housing. The funnel comprises a vertical lower wall portion, and a seawater duct is formed between the vertical lower wall portion and the housing wall portion. This provides a flow of seawater passing upward through the housing.
[0024] In some embodiments, the funnel may comprise sound-absorbing means for absorbing noise generated by the exothermic power unit. Such sound-absorbing means may be, for example, a sound-absorbing material contained in the material of the funnel wall portion and / or a grooved surface.
[0025] Also disclosed is a row of at least two submarine power devices disposed at a seabed location, each submarine power device comprising a liquid-filled housing surrounding an exothermic power unit and further comprising side wall portions. The side wall portions of adjacent housings are arranged to face each other with a mutual distance therebetween.
[0026] The liquid in the liquid-filled housing can be oil or another dielectric liquid.
[0027] In some embodiments, the row can comprise three, four, or five submarine power devices.
[0028] Advantageously, each housing comprises two parallel side wall portions. Further, the row of submarine power devices can be linear.
[0029] The side wall portions can face in a direction parallel to the direction of the linear row.
[0030] One or more of the heat-generating power units of each submarine power device can comprise a submarine transformer.
[0031] In some embodiments, each submarine power device is supported by one or more support devices, and the lower edge of the space defined between the oppositely arranged side wall portions is in fluid communication with the water present below the housing.
[0032] Advantageously, the two oppositely arranged side wall portions arranged with the above mutual distance therebetween can be parallel.
[0033] In some embodiments of the row, the ratio between the area of each side wall portion and the distance between them is in the range of 7 m to 300 m.
[0034] The space between the opposing side wall portions of adjacent submarine power devices can be compartmentalized by baffle plates. This increases the flow rate of seawater between the submarine power devices.
[0035] In another embodiment, the space between the opposing side wall portions of adjacent submarine power devices can comprise a row of pipes having open ends arranged vertically.
[0036] <00001While various features of the present invention have been discussed above in general terms, some more detailed and non-limiting embodiments of the invention are presented below with reference to the drawings. [Brief explanation of the drawing]
[0039] [Figure 1] This is a schematic side view of the water-cooled submarine power plant according to the present invention. [Figure 2] Figure 1 is a schematic perspective view of the embodiment shown, but the power unit is not shown. [Figure 3] This is a schematic side view of an embodiment similar to the embodiment shown in Figure 1, but a funnel is also provided. [Figure 4] This is a perspective view of another embodiment of the present invention. [Figure 5] This is a schematic perspective view illustrating an alternative design for the cooling channel. [Figure 6] Figure 5 shows an embodiment having the cooling channel design illustrated. [Figure 7] This is a schematic cross-sectional side view of a part of the enclosure of a water-cooled submarine power device according to the present invention. [Figure 8] This is a perspective view of a row of submarine power equipment located on the seabed. [Figure 9] This is a schematic side view of the column shown in Figure 8. [Figure 10] This is a top view showing an embodiment having two parallel rows of submarine power equipment. [Figure 11] This is a top view showing an embodiment similar to that illustrated in Figure 10. [Modes for carrying out the invention]
[0040] Figure 1 is a schematic side view of the water-cooled submarine power unit 1, which will henceforth be referred to as the power unit 1. The power unit 1 has an oil-filled housing 3. When the power unit 1 is placed in the sea, such as on the seabed, the housing 3 is surrounded by seawater. The support device 4 supports the weight of the housing 3 and allows seawater to flow in below it.
[0041] The housing 3 has an internal chamber 5. Inside the housing 3, that is, within the internal chamber 5, the power device 1 has a heat-generating power unit 7. Hereafter, the heat-generating power unit 7 will be referred to as the power unit 7. In the illustrated embodiment, the power unit 7 is an electric transformer.
[0042] The housing 3 has a base plate 9 and a top plate 11. The housing 3 has a housing wall portion 13 positioned between the base plate 9 and the top plate 11.
[0043] Since the power unit 7 generates heat, the oil contained in the housing 3 becomes warm and must be cooled. The cooling channel 15 extends through the housing 3 between its respective inlet 17 and outlet 19. The inlet 17 and outlet 19 communicate with the surrounding seawater. Furthermore, since the inlet 17 is lower than the outlet 19, the seawater flows through the cooling channel 15 as it is heated by the walls of the cooling channel 15. This cools the oil in the internal chamber 5, and the oil cools the power unit 7.
[0044] By positioning the cooling channel 15 through the internal chamber 5 and thus bringing it into direct contact with the oil, efficient cooling of the oil can be achieved. Furthermore, by using a temperature difference to obtain the above flow, additional equipment such as pumps and pump motors can be avoided.
[0045] Figure 2 is a perspective view of the embodiment shown in Figure 1, but the power unit 7 is not shown.
[0046] Figure 3 shows another embodiment in which the funnel 21 is positioned to surround the housing 3. The funnel 21 has a base portion having a vertical lower wall portion 23 that is parallel to the housing wall portion 13 and positioned at a horizontal distance from the housing wall portion 13. Above the vertical lower wall portion 23, the funnel 21 has a funnel-shaped portion that terminates in the upper funnel duct 25. The upper funnel duct has a narrower cross-section than the cross-section defined by the vertical lower wall portion 23.
[0047] The seawater duct 24 is formed between the vertical lower side wall portion 23 and the housing wall portion 13.
[0048] Since the enclosure wall 13 of the enclosure 3 is warmer than the surrounding seawater, the seawater is heated by the enclosure 3 and flows upward through the funnel 21, as indicated by the arrow.
[0049] The funnel 21 contributes to the flow of seawater through the cooling channel 15, and therefore not only contributes to the flow through the seawater duct 24 between the funnel 21 and the housing wall 13.
[0050] Some types of heat-generating power units 7, such as transformers, generate noise. The funnel 21 may be used additionally as a sound absorber to reduce the environmental impact of the generated noise. For this purpose, the funnel 21 may be equipped with sound-absorbing means (not shown).
[0051] Suitable materials for the funnel 21 to provide sound-absorbing properties are composite materials, such as GRP (glass-reinforced plastic) and / or other polymer-containing materials. The sound-absorbing means may include, for example, inclusions (e.g., bubbles) in the material (porous material) and / or a grooved surface for sound absorption.
[0052] Referring now to Figure 4, which shows a schematic perspective view of the power device 1 according to the present invention. In this embodiment, the base plate 9 and the top plate 11 are provided with base projections 9a and upper projections 11a that extend horizontally beyond the housing wall 13. A plurality of ribs 27 are arranged between the base projections 9a and the upper projections 11a. The ribs 27 are attached to the housing wall 13, and heat can be transferred from the housing wall 13 to the ribs 27, and therefore to the surrounding seawater. Thus, vertically extending rib channels 29 are formed between pairs of adjacent ribs 27. The seawater present in the rib channels 29 is heated and therefore flows upward in each rib channel 29.
[0053] Furthermore, in the embodiment shown in Figure 4, rib channel openings 31 are advantageously provided in the base projection 9a and the upper projection 11a. The rib channel openings 31 are located at the upper and lower ends of the rib channel 29, respectively. The rib channel openings 31 increase the flow through the rib channel 29, as a significant portion of the flow through the rib channel 29 flows in through the lower channel opening 31 and flows out through the upper channel opening 31. In addition to cooling the housing wall 13, the rib channel openings 31 also contribute to cooling the base plate 9 and top plate 11 of the housing.
[0054] In some embodiments, it may be preferable not to have an outlet 19 for the cooling channel 15 located on the top plate 11. This is the case, for example, in embodiments where pressure compensation equipment (e.g., bellows) is located on top of the housing 3. In such embodiments, as shown in Figure 5, the cooling channel 15 may have an outlet 19 located on the housing wall 13.
[0055] In this embodiment, the cooling channel 15 has a vertical, straight lower portion 15a, a curved portion 15b connected to the upper part of the lower portion 15a, and an end portion 15c that terminates at the outlet 19. The curved portion 15b ensures that the pressure drop with respect to the angle change does not become too large, because the pressure drop reduces the flow of heat-induced seawater through the cooling channel 15.
[0056] The enclosure 3 is advantageous in that pressure equilibrium is achieved, and there is virtually no pressure drop across the walls of the pipes that constitute the cooling channel 15.
[0057] Figure 6 shows this embodiment in a perspective view. As shown, the outlet 19 is located in the rib channel 29. Figure 7 shows a cross-sectional side view of the same embodiment, with various seawater flows indicated by arrows.
[0058] In embodiments comprising a funnel 21, the vertical lower side wall portion 23 of the funnel 21 may be advantageously positioned at a horizontal distance from the rib 27 and the base projection 9a and upper projection 11a.
[0059] Figures 8 and 9 show a solution in which a row 100 of submarine power units 101 are located on the seabed. Each submarine power unit 101 has an oil-filled housing 103. The housing 103 is surrounded by seawater. One or more support devices 104 support the weight of the housing 103 and allow access to the seawater beneath them.
[0060] Each housing 103 has an internal chamber 105. Inside the housing 103, that is, within the internal chamber 105, the power device 101 has a heat-generating power unit 107, which will hereafter be referred to as the power unit 107. In the illustrated embodiment, the power unit 107 is an electrical transformer.
[0061] The housing 103 has side walls 113. The submarine power devices 101 are arranged in rows 100 such that the side walls 113 of different power devices 101 face each other with a distance of 140 between them.
[0062] Advantageously, as shown in this embodiment, the opposing side walls 113 may be substantially parallel.
[0063] This configuration of row 100 heats the water present between the opposing side walls 113. The heated water rises, resulting in an upward flow of water in the space between the opposing side walls 113. This is indicated by the arrows inserted in Figure 9. The water flow contributes to the cooling of the side walls 113 and, therefore, to the cooling of the oil inside the housing 103.
[0064] To achieve this effect, the distance between the two opposing side walls should not be too large. Furthermore, if there is not enough water between the side walls 113, the water may flow, but the cooling effect may be minimal.
[0065] Therefore, an appropriate ratio R must be selected between the area of the side wall portion 113 and the distance 140 between them. For example, each side wall portion 113 is 3m × 4m = 12m 2 It may have an area of . The distance between them may be 0.5m. Then the ratio R is 12m 2 / 0.5m = 24m. The appropriate range for the ratio R can be from 7m to 300m.
[0066] A particular advantage of supporting the submarine power unit 101 while it is lifted by the support device 104 is that water can access the area between the opposing side walls 113 from below. In such an embodiment, the lower edge of the space defined between the opposing side walls 113 is in fluid communication with the water present below the housing 103.
[0067] Figure 10 is a top view of two parallel rows 100 of the submarine power plant 101. The relative distance 140 between the sidewalls 113 is shown for the sidewalls 113 extending in different orthogonal directions. Furthermore, baffles 115 are positioned to close the space between the sidewalls 113. This results in increased seawater flow and, therefore, also improves the cooling function. It should be obvious to those skilled in the art that the baffles 115 are optional. Advantageously, the baffles 115 can be oriented vertically.
[0068] Figure 11 shows an embodiment similar to the embodiment illustrated in Figure 10. Instead of baffles 115, a row of pipes 117 is arranged between the side walls 113 of adjacent power units 1. The pipes 117 may be arranged vertically and open at both ends. They may be advantageously made of metal to ensure good heat transfer through their walls. The pipes 117 provide efficient flow of seawater between the side walls 113 of the housing, thus improving the cooling function.
Claims
1. A water-cooled submarine power device (1) comprising a liquid-filled housing (3) surrounding a heat-generating power unit (7), A water-cooled submarine power device (1) further comprising a plurality of cooling channels (15), wherein the cooling channels (15) penetrate the housing (3) and have an inlet (17) and an outlet (19), the inlet being positioned vertically below the outlet, and both the inlet (17) and outlet (19) of each cooling channel (15) being in liquid communication with the surrounding seawater.
2. The water-cooled submarine power device (1) according to claim 1, characterized in that the housing (3) comprises a base plate (9) and a top plate (11), and the inlet (17) is positioned on the base plate (9).
3. The housing (3) includes a vertical housing wall portion (13) extending between the base plate (9) and the top plate (11), The base plate and the top plate extend horizontally beyond the housing wall portion (13), The housing (3) further comprises a plurality of ribs (27) extending between the base plate and the top plate, the ribs (27) in contact with the housing wall (13) and extending outward from the housing wall (13), The water-cooled submarine power device (1) according to claim 2, characterized in that the base plate (9) and the top plate (11) are provided with rib channel openings (31) at each end of rib channels (29) extending between adjacent ribs (27).
4. The water-cooled submarine power device (1) according to claim 2, or claims 2 and 3, characterized in that the outlet (19) is located on the top plate (11).
5. The water-cooled submarine power device (1) according to claim 2, or claims 2 and 3, characterized in that the outlet (19) is located in the housing wall (13).
6. The cooling channel (15) is characterized by comprising a vertical, straight lower portion (15a), a curved portion (15b) connected to the upper part of the lower portion, and an end portion (15c) that terminates at the outlet (19), as described in any one of claims 1 to 5.
7. The water-cooled submarine power device (1) according to any one of claims 1 to 6, characterized in that the power unit (7) is a transformer, a switchgear, a variable speed drive, a rectifier, a frequency converter, or a current collector.
8. A water-cooled submarine power device (1) according to any one of claims 1 to 7, further comprising a funnel (21) arranged around the housing (3), wherein the funnel has a vertical lower side wall portion (23) that forms a seawater duct between itself and the housing wall portion (13).
9. The water-cooled submarine power device (1) according to claim 8, characterized in that the funnel (21) is provided with sound-absorbing means for absorbing noise generated by the heat-generating power unit (7).
10. A row (100) of at least two submarine power devices (101) arranged on the seabed, wherein each submarine power device (101) comprises a liquid-filled housing (103) and side walls (113) surrounding a heat-generating power unit (7), and the side walls (113) of adjacent housings (103) are arranged to face each other with a distance (140) between them.
11. Each of the submarine power devices (101) is supported by one or more support devices (104), and the lower edge of the space defined between the opposing side wall portions (113) is in fluid communication with water present below the housing (103), according to claim 10.
12. The row (100) according to claim 10 or 11, wherein the ratio (R) between the area of each of the side wall portions (113) and the distance between them (140) is in the range of 7 m to 300 m.
13. The row (100) according to any one of claims 10 to 12, wherein the space between the opposing side walls (113) of adjacent submarine power devices (101) is closed by a baffle plate (115).
14. The row (100) according to any one of claims 10 to 12, wherein the space between the opposing side walls (113) of adjacent submarine power devices (101) comprises a row of vertically arranged pipes (117) having open ends.
15. A row (100) according to any one of claims 10 to 14, which is arranged to face another row (100) according to any one of claims 10 to 12, with a distance (140) between them.
16. A row (100) according to any one of claims 10 to 15, comprising the submarine power device (1, 101) according to any one of claims 1 to 9.