SHIP

Abstract

The invention concerns a ship comprising at least one electric motor for driving a ship and a cooling device for cooling the at least one electric motor by means at least one coolant. It is further according to the invention that the cooling device has a heat exchanger adapted to cool the at least one coolant by means of sea water.

Description

BACKGROUND

1. Technical Field

The invention concerns a ship comprising at least one electric motor for driving the ship and a cooling device for cooling the at least one motor by means of a coolant. The invention further concerns a cooling device for a ship having at least one electric motor.

2. Description of the Related Art

Hitherto the proportion of ships was implemented predominantly by means of internal combustion engines. Electric drives were also quite often used in relation to smaller ships, for example in the leisure industry. In recent times trials are also being undertaken to drive larger ships, such as for example for cargo ships and container ships, by means of electric drives. The climate at sea represents a problem for those drives which frequently have a complicated and expensive electronic system. In particular cooling such electric drives for cargo ships is a problem which hitherto has been only inadequately resolved.

BRIEF SUMMARY

One or more embodiment of the present invention is to make a contribution to resolving that problem, giving in particular an electric motor-driven ship with improved cooling.

In a ship of the kind set forth in the opening part of this specification a cooling device has a heat exchanger adapted to cool the at least one coolant by means of sea water.

Accordingly a ship according to one embodiment of the invention has at least two cooling circuits which are coupled together. In a first circuit, coolant circulates between the at least one electric motor and the heat exchanger. In a second circuit, sea water circulates between the heat exchanger and an outside region of the ship. The two circuits are separated from each other by the heat exchanger in such a way that coolant and sea water do not mix. As a result the at least one electric motor does not come into contact with sea water. Thus, corrosion of the at least one electric motor is substantially reduced and as a result the service life is substantially prolonged. The maintenance expenditure and complication is also substantially reduced. The construction and manufacture of such an electric motor is also simplified as it does not have to be designed for direct cooling operation by means of sea water. A further advantage is also that a ship with a drive designed in that way is improved in terms of energy consumption and reliability. Sea water represents a natural and almost unlimited cooling resource. The temperature of the sea water is in that respect substantially constant in a voyage with the ship so that such a cooling device does not require permanent adaptive adjustment. In addition there is no need for complicated cooling apparatuses to be installed on board a ship whereby on the one hand operational reliability and on the other hand the energy consumption of such a ship are improved. Preferably the heat exchanger is in the form of a counter-flow heat exchanger. Alternatively the heat exchanger is the form of a co-flow heat exchanger. According to one embodiment of the invention it is also possible to use a plurality of heat exchangers so that the coolant can be cooled in a multi-stage heat exchange process.

In a first preferred embodiment the coolant is air and/or fresh water. According to the invention the term fresh water here does not denote sea water but for example cooling water, cooling fluid and also water-oil emulsions and the like. Air refers here to space air and not to salty sea air. Those two coolants are particularly preferred as they are readily available and are already used in many cases for electric motors. In that respect, heat exchange of sea water to fresh water is easy to implement by virtue of good thermal conduction. Especially adapted heat exchangers are preferably to be used for heat exchange from sea water to air.

In a further preferred embodiment the coolant is air and a rotor and/or a stator of the electric motor can be cooled by means of said air. In particular air is preferred for cooling a rotor of an electric motor. The cooled air can be passed for example through a gap between the rotor and the stator, cooling ribs can be arranged at the stator, or cooling passages through which the cool air can be passed are taken through the stator. In addition the air can be passed into an internal hollow space in the rotor and thus cool it.

In a further preferred embodiment the at least one electric motor is arranged in a substantially air-tightly closed engine room of the ship and of the air for cooling the electric motor is room air. Thus the at least one electric motor is not exposed to salty air whereby corrosion of the motor is substantially avoided. That provides that on the one hand maintenance of such a motor or a ship according to the invention having such a motor and such a cooling device is substantially reduced and the operational reliability of the ship is improved. In accordance with this preferred embodiment, each motor can be provided with a dedicated room, or all motors are arranged jointly in a substantially air-tightly closed room. In addition an energy supply for the motors can also be arranged in that room. The heat exchanger can also be arranged in an air-tightly closed room or can be in fluid communication with that room in some other way.

In accordance with a further preferred embodiment means for conveying air, such as by one or more fans, are arranged at a cooling air inlet and/or a warm air outlet of the electric motor. Thus cool air can be guided in specifically targeted fashion to the electric motor or can be caused to impinge thereagainst. That air can also be guided in cooling passages, over cooling ribs, in openings or hollow spaces or the like to the electric motor. In addition warm air can be carried away from the electric motor in a specifically targeted fashion. That makes it possible to achieve specifically targeted cooling of the motor. In addition a specifically targeted volume flow or a specifically targeted air speed can be placed over the motor so that it can be cooled in improved targeted fashion. That makes it possible to increase the efficiency of the motor and the service life of a motor is prolonged. The maintenance complication and expenditure is also further reduced.

In a further preferred embodiment means for guiding the air is/are arranged between a cooling air inlet of an electric motor and a cooling air outlet of the heat exchanger and/or between a warm air outlet of the electric motor and a warm air outlet of the heat exchanger. Such means can include for example hoses, passages, tubes, shafts and so forth. A specifically targeted air feed and discharge is thus afforded according to the invention and effective cooling of the motor is improved. Additionally or alternatively the means for guiding the air can have means for conveying air. In an embodiment the means for guiding the air are arranged between a cooling air inlet of the electric motor and a cooling air outlet of the heat exchanger. In this embodiment cooling air is passed specifically to the motor by means of the means for guiding the air, the motor is cooled by means of the air supplied thereto, the warm air is then discharged into the room which is preferably air-tightly closed. The heated room air is then cooled again by means of the exchange effect. In an alternative the means for guiding the air are arranged between a warm air outlet of the electric motor and a warm air inlet of the heat exchanger. In this embodiment the warm air is carried away from the electric motor, and towards the heat exchanger, by means of which it is cooled. The cooled air is then discharged into the room which is preferably air-tightly closed. In a further embodiment the means for guiding the air are arranged both between a cooling air outlet of the heat exchanger and a cooling air inlet of the electric motor, and also between a warm air outlet of the electric motor and a warm air inlet of the heat exchanger. Accordingly the cooling air circulates in a substantially closed system. In this embodiment the room does not have to be air-tightly closed, but rather it is sufficient for the motors to be protected from salty air.

In a further preferred embodiment the at least one electric motor has cooling passages at a housing and/or at a stator. The cooling passages can pass through the housing and/or along a stator winding. Specifically targeted cooling of a motor is possible by means of such cooling passages. The cooling passages can be designed using various geometries, for example straight, curved, in a zig-zag shape or also in a different fashion. Ribs can also be arranged in the passages to achieve still more effective cooling.

In a further embodiment cooling air can be passed through the cooling passages and/or a gap between the stator and a rotor. That advantageously develops effective cooling of the electric motor. Means for guiding the air and/or means for conveying the air for example can be connected to the cooling passages.

In a further preferred embodiment the coolant is fresh water which can be passed through the cooling passages for cooling the electric motor. That permits still more effective cooling of an electric motor. In this embodiment the fresh water is cooled by means of the heat exchanger, passed through tubes, hoses or the like to the passages, passed through the passages and then passed heated again back to the heat exchanger.

In a further preferred embodiment the cooling device has a second heat exchanger which can be connected to a first heat exchanger and which is adapted to cool air by means of fresh water, wherein the fresh water can be cooled by means of the first heat exchanger by means of sea water. Thus fresh water and air can be cooled with a heat exchanger. It is for example possible to cool fresh water by sea water with a large primary heat exchanger, and to pass that fresh water to various motors or other items of equipment in the ship such as for example the diesel-generating assemblies. The electric motors can accordingly each have a respective dedicated second small heat exchanger, by means of which air is cooled by the cool fresh water. The fresh water can then be additionally used to cool for example the stator of the motor while the cooled air is used to be passed through a gap between the rotor and the stator and thus cool the rotor. In a further preferred embodiment the first heat exchanger can be connected to a stator of the electric motor and is adapted to cool it by means of the fresh water.

In a further preferred embodiment the energy supply has a converter and the converter can be cooled by means of fresh water. In particular it is preferable for those inverters to be cooled by means of the fresh water as they are preferably arranged in positional proximity with the electric motors. It is equally preferable for both the converter cooling or the energy supply cooling and the electric motor cooling to be arranged on the same cooling circuit of fresh water. It is however also possible to provide different cooling circuits.

In a further aspect of the invention, in a cooling device of the kind set forth in the opening part of this specification, the object is attained in that a cooling device is of a configuration corresponding to one of the above-mentioned embodiments. Such a cooling device can be used in a large number of ships, marine vessels or yachts to cool for example electric motors or also other devices to be cooled. Such a cooling device contributes to making the ship low-maintenance and operationally reliable and to reduce energy consumption. All the above-mentioned advantages are achieved when such a cooling device is used in a ship.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described hereinafter by means of embodiments by way of example with reference to the accompanying drawings in which:

FIG. 1 shows a partly broken-away perspective view of a ship according to the invention,

FIG. 2 shows a diagrammatic view of a first embodiment of a cooling device,

FIG. 3 shows a diagrammatic view of a second embodiment of a cooling device,

FIG. 4 shows a diagrammatic view of a third embodiment of a cooling device,

FIG. 5 shows a diagrammatic view of a fourth embodiment of a cooling device.

DETAILED DESCRIPTION

The ship 102 shown in FIG. 1 has on a deck 114 four Magnus rotors 110 as propulsion devices. Besides the Magnus rotors 110, the ship also optionally has a bridge 130 as well as a crane 105 and a crane 103 on the deck 114. As a further propulsion device the ship additionally has a propeller 150 at the stern of the ship 102. The propeller 150 can be connected by way of a shaft 111 to two electric motors 108, 109. The electric motors 108, 109 are fed with electric current by way of two converter cabinets 115, 116. Arranged above the electric motors 108, 109 and the converter cabinets 115, 116 is a deck 172 which preferably air-tightly closes the engine room in relation to a cargo hold. Preferably large-volume electric motors, for example synchronous machines, involving a low rotary speed, are used as the electric motors 108, 109 so that a transmission does not necessarily have to be provided in the overall drive train. The motors can also be operated selectively. For light to pass into the interior of the ship 102 it has windows 118 at the sides.

FIGS. 2 to 4 show embodiments by way of example of a cooling device according to the invention for a ship 102 according to the invention, by means of which the electric motors 108, 109 can be cooled.

As shown in FIG. 2 the cooling device 1 in the first embodiment has a heat exchanger 2 which can be fed on one side 4 with a flow 16 of sea water. The flow of sea water is only diagrammatically indicated here by the arrows. In the case of a ship 102 as shown in FIG. 1 the sea water flow 16 can be passed to and away from the heat exchanger 2 by means of tubes. At a second side 6 the heat exchanger 2 has an air inlet 24 and an air outlet 26. Air can thus be cooled by means of this heat exchanger 2.

FIG. 2 also shows an electric motor 8. The electric motor 8 has a stator 10 which can have a stator housing. The electric motor 8 also has a rotor which rotates about an axis of rotation 14 in operation and can be coupled to a drive unit of a ship such as for example a shaft 111 and propeller 150 (FIG. 1). The electric motor 8 together with its components is arranged in a room 19 which is substantially air-tightly closed by a wall 18. The heat exchanger 2 together with its components is arranged outside the room 19. The stator or stator housing 10 of the electric motor 8 also has an air inlet 20 and an air outlet 22. Arranged thereat as a means for conveying the air is a respective fan 20a, 22a for conveying the air into and out of the motor 8; alternatively other pumps such as vane pumps or the like could be used for that purpose. Preferably the air can be passed through cooling passages in the stator or the stator housing 10 and/or a gap between the rotor 12 and the stator 10. A tube 30 is arranged between the air outlet 22 and the air inlet 24 of the heat exchanger 2. Warm air is carried out of the motor 8 and passed to the heat exchanger 2 by way of the tube 30. The cool air which issues from the air outlet 26 of the heat exchanger 2 is passed by means of a second tube 32 to an air inlet 28 of the room 19 in the wall 18. The air passes out of that air inlet 28 into the room 19 so that it is overall filled with cool air. The cool room air is then sucked in by the fan 20a at the air inlet 20 and is passed into the cooling passages of a gap between the rotor 12 and the stator 10. By the room 19 being filled with cool air, the fan 20a in the inlet 20 can suck in air as needed to cool the motor 8 to a temperature which is preferred for optimum performance. The motor 8 is also cooled by way of air which is not blown or sucked directly into the motor 8, but flows along the surface thereof. Preferably the room 19 is air-tightly closed by means of the wall 18 or decks, doors, hatches and the like so that in the case of a ship 102 (FIG. 1) no salty air or as little salty air as possible passes into the room 19. Alternatively it is also in accordance with the invention for the room 19 not to be air-tightly closed, but for an increased pressure to obtain within the room 19 so that salty air cannot flow from the exterior into the interior of the room 19. It is also possible for a tube to be arranged between the inlet 28 of the room 19 and the inlet 20 of the motor and/or for no tube 30 to be arranged between the outlet 22 of the motor 8 and the inlet 24 of the heat exchanger 2.

In the second embodiment of the cooling device 1 shown in FIG. 3 the cooling device 1 has a first heat exchanger 2 and a second heat exchanger 3. The two heat exchangers 2, 3 are coupled to a motor 8 and serve to cool it by means of coolant. The first heat exchanger 2 is arranged in a first cooling circuit which substantially corresponds to the first embodiment shown in FIG. 2 of the cooling device 1. The second circuit in which the second heat exchanger 3 is arranged uses fresh water such as for example cooling water or other cooling fluid as coolant. The second heat exchanger 3 is coupled like the first heat exchanger 2 to a sea water flow 17, wherein that sea water flow 17 once again in the case of a ship 102 as shown in FIG. 1 can be passed for example by way of tubes from an external region of the ship 102 to the heat exchanger 3. The heat exchanger 3 is connected at a second side 7 to two cooling water conduits 34, 36 which each have a respective pump 38, 40. The pumps 38, 40 are adapted to deliver a corresponding cooling water flow. The cooling water conduits 34, 36 lead from outside the room where the heat exchanger 3 is also arranged into the interior 19 of the room and are there connected to a cooling body 42. For that purpose the cooling body 42 has a cooling water inlet 44 and a cooling water outlet 46. As shown in FIG. 3 the cooling body 42 is arranged at an outer portion of the motor housing or the stator 10 of the electric motor 8. That is only a diagrammatic view. It is also possible to provide in a housing or in the stator 10, cooling passages through which cooling water can be passed. In this embodiment it is possible for example for the rotor 12 to be substantially cooled with the air which can be passed through the air inlet 20 into the interior of the motor 8, and for the stator 10 of the motor 8 to be cooled substantially with water which can be cooled by way of the heat exchanger 3 by means of the sea water flow 17 and which circulates by means of the cooling water conduits 34, 36 between the heat exchanger 3 and the cooling body 42.

FIG. 4 shows a further alternative of a cooling device 1. In addition to the cooling device 1 shown in FIG. 3 the cooling device 1 of FIG. 4 has a third cooling circuit. The third cooling circuit is fed like the second cooling circuit by means of the heat exchanger 3 which is adapted to cool cooling water by means of a sea water flow 17. As shown in FIG. 4 two further cooling water conduits 35,37 branch from the cooling water conduits 34, 36 and pass cooling water to and away from a converter cabinet 48. The converter cabinet 48 is connected to the electric motor 8 by way of a power supply cable 50. Arranged in the converter cabinet 48 is a plurality of converters adapted to provide electric current at a voltage and a frequency which are required by the electric motor 8. To ensure optimum operation of a converter cabinet 48 it is preferable for it to be cooled. In the illustrated embodiment the converter cabinet 48 or the converters contained therein is cooled with cooling water cooled by means of the heat exchanger 3 by means of a sea water flow 17. The cooled cooling water is conveyed on a second side 7 of the heat exchanger 3 by a pump 40, and flows through a cooling water feed conduit 37 to the converter cabinet 48. A plurality of cooling bodies can be arranged therein, or plates or the like which transport heat away from the converters. The heated water is then conveyed away from the converter cabinet 48 by means of the cooling water conduit 35 and the pump 38 and passes to the heat exchanger 3 again. The two further cooling circuits are of a configuration corresponding to the circuits in FIG. 3.

A further alternative of the cooling device 1 is shown as an embodiment in FIG. 5. In this embodiment (FIG. 5) the cooling device 1 has substantial features in common with the embodiment of FIG. 3. The circuits used for cooling the electric motor 8 in the embodiment of FIG. 5 are in cascade relationship. The cooling device has a first heat exchanger 2 and a second heat exchanger 3. The heat exchanger 3 has a first side 5 and a second side 7, wherein a sea water flow 17 can be passed into the first side 5 and cooling water conduits 34, 36 are connected to the second side. The first heat exchanger 2 also has a first side 4 and a second side 6, with two cooling water conduits 52, 54 being connected to the first side 4 and two air passages 30, 32 to the second side 6. The cooling water conduit 52, 54 lead to the second side 7 of the second heat exchanger 3. The co-operation of the air passages 30, 32 with the electric motor 8 and the cooling passages 34, 36 with the cooling element 42 are of a configuration corresponding to the embodiment of FIG. 3. In the present embodiment (FIG. 5) a sea water flow 17 is used to cool cooling water which then is used on the one hand to cool the electric motor 8 by way of a cooling body 42 and on the other hand is used in the first heat exchanger 2 to cool air which then in turn is used to cool the electric motor 8 and in particular the rotor 12. Thus only one sea water access is necessary for the overall cooling system and in addition corrosion in the first heat exchanger 2 can be very substantially avoided.

If more than one motor 8, 108, 109 is arranged in a ship 102 (FIG. 1), a cooling device can be provided for each motor or a common cooling device can be provided for a plurality of motors. If a cooling device is designed for a plurality of motors as in the embodiment of FIG. 5 a first heat exchanger 2 can be arranged for example for each electric motor 8, 108, 109, in which case that plurality of first heat exchangers 2 co-operative with a single second heat exchanger 3.

The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent application, foreign patents, foreign patent application and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, application and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

Claims

1. A ship comprising:

a propeller;

at least one electric motor for driving the propeller; and

a cooling device that includes a coolant for cooling the at least one electric motor, the cooling device including a heat exchanger adapted to cool the coolant by sea water.

2. The ship according to claim 1 wherein the coolant is at least one of air and fresh water.

3. The ship according to claim 1 wherein:

the coolant is air; and

the electric motor includes a rotor and a stator that are cooled by said air.

4. The ship according to claim 3 wherein the at least one electric motor is arranged in a substantially air tight engine room of the ship, and the air for cooling the electric motor is the air in the engine room.

5. The ship according to claim 3 further comprising means for conveying air through the cooling device, wherein the cooling device includes a cooling air inlet and a warm air outlet of the electric motor.

6. The ship according to claim 5 further comprising means for guiding the air that is arranged between a cooling air inlet of an electric motor and a cooling air outlet of the heat exchanger.

7. The ship according to claim 1 wherein the at least one electric motor includes a rotor and a stator located in a housing, the cooling device including cooling passages in at least one of the housing and the stator of the at least one electric motor.

8. The ship according to claim 7 wherein cooling air can be passed through at least one of the cooling passages and a gap between the stator and the rotor.

9. The ship according to claim 7 wherein the coolant is fresh water that is passed through the cooling passages for cooling the electric motor.

10. The ship according to claim 3 wherein the heat exchanger is a first heat exchanger, the cooling device further including a second heat exchanger coupled to the first heat exchanger, the second heat exchanger being adapted to cool a coolant by fresh water, wherein the fresh water is cooled by sea water of the first heat exchanger.

11. The ship according to claim 10 wherein the first heat exchanger is coupled to the stator of the electric motor and is adapted to cool the stator by means of the fresh water.

12. The ship according to claim 1 further including an energy supply that is cooled by the coolant.

13. The ship according to claim 12 wherein the energy supply has at least one converter that is cooled by fresh water.

14. A cooling device for a ship comprising:

a cooling passage that includes a coolant for cooling at least one electric motor; and

a heat exchanger located around a portion of the cooling passage and adapted to cool the coolant using sea water.

15. The cooling device according to claim 14, the coolant is one of air or fresh water.

16. The cooling device according to claim 14, wherein the cooling passage includes an inlet and an outlet, at least one of the inlet and the outlet including a fan for conveying the coolant through the cooling passage.

17. The cooling device according to claim 14, wherein the cooling passage is a first cooling passage that includes air as the coolant, wherein the heat exchanger is a first heat exchanger, the cooling device further comprising:

a second cooling passage that includes fresh water coolant for cooling the at least one motor; and

a second heat exchanger located around a portion of the second cooling passage and adapted to cool the fresh water coolant using sea water.

18. The ship according to claim 5, wherein the means for conveying air through the cooling device is a fan arranged at least one of the cooling air inlet and the warm air outlet.

19. The ship according to claim 5 further comprising means for guiding the air is arranged between a warm air outlet of the electric motor and a warm air outlet of the heat exchanger.