Wind turbine cooling systems

Abstract

The present invention relates to a wind turbine cooling system configured to cool components of a wind turbine, the wind turbine having a nacelle, the wind turbine cooling system comprising a cooling medium configured to circulate in a cooling circuit, the cooling circuit fluidically connecting the components and a cooling device, the cooling device being arranged on an outer surface of the nacelle and exposed to environmental conditions, such as wind flow and ambient air temperature outside the nacelle, the cooling medium being cooled in the cooling device by the wind flow passing through the cooling device, the cooling medium circulating from the cooling device to the components, wherein a first temperature changing section is fluidically connected to the cooling circuit upstream of the cooling device, the first temperature changing section being configured to heat the cooling medium before the cooling medium enters the cooling device, and a second temperature changing section is fluidically connected to the cooling circuit downstream of the cooling device, the second temperature changing section being configured to cool the cooling medium after the cooling medium has left the cooling device.

Description

Technical Field

[0001] The present invention relates to a wind turbine cooling system and cooling method configured to cool components of a wind turbine. Background Art

[0002] A wind turbine is essentially a machine that harvests kinetic energy from the wind and applies that energy to a rotating shaft, ultimately converting the mechanical energy into electrical energy. This energy conversion occurs through numerous key components within a wind turbine, but the conversion is thermodynamically imperfect, meaning it includes losses, meaning that a portion of the energy harvested from the wind is dissipated as heat rather than being converted into electricity. Losses occur in the form of heat generated in varying amounts within the components. The location of the components varies from wind turbine to wind turbine; some may be placed near the base or top of the wind turbine's tower, but a common feature is that most components are placed close together in the nacelle, which is a critical part of the wind turbine's structural integrity.

[0003] Components vary in type and size. Heat-generating components can include large, heavily loaded mechanical components like bearings, brakes, gearboxes, generators, pumps, hydraulic systems, and fans, as well as power electronics like large transformers and converters. The amount of heat dissipated by each component also varies, as does their dependence on the wind turbine's total power output, meaning that heat losses from some components are more affected than others by the wind turbine operating at part load.

[0004] For the reasons mentioned above, wind turbines typically have cooling systems to transfer heat from key components to prevent overheating. This type of cooling system may include pumps, valves, piping, cooling units, heat exchangers, and a cooling medium. The pump circulates the cooling medium through the piping within the cooling system, absorbing heat as it passes through the heat-generating components. The heated cooling medium ultimately reaches the cooling unit located outside the nacelle, where it is exposed to ambient temperature and local wind conditions. Here, the cooling medium is cooled while passing through the cooling unit and returned to the pumping unit to complete the circuit.

[0005] In addition to cooling specific components, the cooling system can also include ambient cooling of the cabin itself. This can be done by connecting fans and air heat exchangers to the cooling system, or it can be designed as a separate cooling system.

[0006] To avoid overheating, wind turbines must have access to sufficient cooling to keep component temperatures within acceptable limits. If temperatures rise too high, the wind turbine may be damaged or fail due to overheating. One way to avoid this is to reduce power output, which means producing less energy than the current wind conditions would normally allow, as lower output results in less wasted heat dissipation. Reduced energy production means less energy can be sold to the grid, resulting in lost profits.

[0007] As described above, known cooling systems ensure that heat is transported and dissipated from the interior of the nacelle to the external surroundings via a cooling device placed outside the nacelle. The cooling medium flow rate, controlled by a pump, is a system parameter and, in most cases, is constant during wind turbine operation. If the incoming wind is assumed to have a constant velocity, the amount of heat that the cooling device can dissipate into the environment depends solely on the temperature difference between the heated cooling medium reaching the cooling device and the local ambient air temperature. Specifically, in cold climates, this temperature difference is large, meaning that the cooling device has no problem dissipating heat from the nacelle. However, in hot climates, this difference is smaller, meaning that the cooling device may not be able to dissipate enough heat to ensure adequate cooling of the wind turbine. This can lead to the aforementioned overheating of components, which is to be avoided. Summary of the Invention

[0008] An object of the present invention is to wholly or partially overcome the above-mentioned drawbacks and disadvantages of the prior art. More specifically, an object is to provide an improved wind turbine cooling system that can cool heat-generating components of a wind turbine even when the temperature difference between the ambient temperature and the temperature of the cooling medium is small.

[0009] The solution according to the invention achieves the above objects and many other objects, advantages and features which will become apparent from the following description by a wind turbine cooling system configured to cool components of a wind turbine having a nacelle, the cooling system comprising

[0010] a cooling medium configured to circulate in a cooling circuit, which fluidically connects the components and the cooling device,

[0011] - the cooling device is arranged on the outer surface of the nacelle and is exposed to environmental conditions, such as wind flow and ambient air temperature outside the nacelle,

[0012] - The cooling medium is cooled in the cooling device by the air flow passing through the cooling device,

[0013] - Cooling medium circulates from the cooling device to the components,

[0014] wherein the first temperature-changing section is fluidically connected to the cooling circuit upstream of the cooling device, and the first temperature-changing section is configured to heat the cooling medium before the cooling medium enters the cooling device; and

[0015] The second temperature-changing section is fluidically connected to the cooling circuit downstream of the cooling device, and the second temperature-changing section is configured to cool the cooling medium after the cooling medium leaves the cooling device.

[0016] Hereby, an improved wind turbine cooling system is obtained for achieving optimal temperature levels of wind turbine components without reducing the power output of the components and the wind turbine even when ambient conditions change, i.e. when the wind turbine is operated for example in hot climates.

[0017] Furthermore, the first and second temperature-varying sections can be integrated into a temperature-varying device. This allows the first and second temperature-varying sections to be integrated into a single temperature-varying device. This allows energy used for the first temperature-varying section to be utilized from the second temperature-varying section, minimizing overall energy usage.

[0018] Furthermore, the first temperature changing section and the second temperature changing section may be operably connected.

[0019] Furthermore, the second temperature varying section may operate independently of the first temperature varying section.

[0020] The wind turbine cooling system may further include a first valve unit configured to fluidly connect the components with the cooling device and / or the first temperature changing section.

[0021] Furthermore, the wind turbine cooling system may further include a second valve unit configured to fluidly connect the cooling device with the components and / or the second temperature changing section.

[0022] The first valve unit may have an inlet, a first outlet, and a second outlet, the first valve unit being configured to have a first position in which the inlet is fluidly connected to the first outlet and a second position in which the inlet is fluidly connected to the second outlet, and wherein the inlet is fluidly connected to the components, the first outlet is fluidly connected to the cooling device, and the second outlet is fluidly connected to the first temperature changing section.

[0023] Moreover, the second valve unit may have an inlet, a first outlet and a second outlet, the second valve unit being configured to have a first position in which the inlet is fluidly connected to the first outlet and a second position in which the inlet is fluidly connected to the second outlet, and wherein the inlet is fluidly connected to the cooling device, the first outlet is fluidly connected to the components, and the second outlet is fluidly connected to the second temperature change section.

[0024] In addition, the first valve unit may include a first valve having a first valve position in which the component is fluidly connected to the cooling device and a second valve position in which the fluid communication through the first valve is closed, and a second valve having a first valve position in which the component is fluidly connected to the first temperature change section and a second valve position in which the fluid communication through the second valve is closed.

[0025] In addition, the second valve unit may include a first valve having a first valve position in which the cooling device is fluidly connected to the component and a second valve position in which the fluid communication through the first valve is closed, and a second valve having a first valve position in which the cooling device is fluidly connected to the second temperature change section and a second valve position in which the fluid communication through the second valve is closed.

[0026] When the first valve is in the first valve position, the second valve may be in the second valve position, and vice versa.

[0027] The first valve and the second valve may be shut-off valves, two-way valves, or throttle valves.

[0028] Furthermore, the ambient temperature sensor may be arranged to measure the ambient air temperature and / or the second temperature sensor may be configured to measure the temperature of the cooling medium downstream of the cooling device.

[0029] Furthermore, a first temperature sensor may be arranged in the wind turbine cooling system, which is configured to measure the temperature of the cooling medium downstream of the component.

[0030] The wind turbine cooling system may further include a control unit operatively connected to the first temperature changing section, the second temperature changing section, the ambient air temperature sensor, the first temperature sensor, the second temperature sensor, the first valve unit, and / or the second valve unit.

[0031] The control unit can be configured to change the temperature of the cooling medium upstream of the cooling device with respect to the measured ambient air temperature and / or the measured cooling medium temperature downstream of the cooling device, so that the temperature of the cooling medium upstream of the cooling device is greater than the ambient temperature and / or the cooling medium temperature downstream of the cooling device.

[0032] In addition, the temperature of the cooling medium upstream of the cooling device can be 5°C higher than the ambient air temperature and / or the cooling medium temperature downstream of the cooling device, preferably 10°C higher than the ambient air temperature and / or the cooling medium temperature downstream of the cooling device, and more preferably more than 15°C higher than the ambient air temperature and / or the cooling medium temperature downstream of the cooling device.

[0033] In addition, the cooling medium may have a first temperature downstream of the component, a second temperature upstream of the cooling device, a third temperature downstream of the cooling device, and a fourth temperature downstream of the second temperature changing section, and the fourth temperature is lower than the third temperature.

[0034] The first temperature may be between 40-65°C, the second temperature may be between 45-80°C, the third temperature may be between 35-55°C, and the fourth temperature may be between 30-50°C.

[0035] Furthermore, the temperature changing device may be a refrigeration system, such as a refrigeration device, which removes heat from a liquid via a vapor compression or absorption refrigeration cycle and rejects the heat elsewhere.

[0036] Furthermore, the temperature level may correspond to a pressure level at which the working medium provided in the temperature changing device by means of the compressor undergoes a phase change.

[0037] The cooling medium from the cooling device may be fluidly connected to the second temperature changing section via a heat exchanger so that the cooling medium may be further cooled to a lower temperature before it reaches the components.

[0038] Additionally, the second temperature changing section may be configured to reduce the temperature of the cooling medium by absorbing heat in the working medium, and the temperature changing device may be configured to transport and dissipate the heat to the first temperature changing section of the temperature changing device.

[0039] The cooling medium from the components may be fluidly connected to the first temperature changing section where the cooling medium receives dissipated energy via the heat exchanger at a higher temperature and causes the temperature of the cooling medium to be increased before the cooling medium reaches the cooling device.

[0040] Furthermore, temperature changing devices may be energy consuming.

[0041] In addition, the temperature changing device can be arranged inside or outside the cabin.

[0042] Components may be bearings, brakes, gearboxes, generators, pumps, hydraulic systems, fans and / or power electronics such as transformers and converters.

[0043] Furthermore, the components may be arranged inside and / or outside the nacelle. Some components may even be arranged at a distance from the nacelle.

[0044] The cooling medium can be water, water-glycol, other water and antifreeze.

[0045] Furthermore, the working medium may be a natural refrigerant, such as water, propane, CO2, ammonia, etc., or may be a synthetic refrigerant.

[0046] The invention also relates to a wind turbine comprising a wind turbine cooling system as described above.

[0047] The invention further relates to a cooling method for cooling one or more components of a wind turbine by means of a wind turbine cooling system and may comprise:

[0048] - measuring a first temperature of the cooling medium downstream of the component,

[0049] - raising the temperature of the cooling medium upstream of the cooling device to a second temperature,

[0050] - reducing the temperature of the cooling medium in the cooling device to a third temperature, and

[0051] - reducing the temperature of the cooling medium downstream of the cooling device to a fourth temperature lower than the third temperature.

[0052] In addition, the cooling method may further include:

[0053] - measuring the ambient air temperature and / or the cooling medium temperature downstream of the cooling device,

[0054] - varying the second temperature of the cooling medium upstream of the cooling device with respect to the determined ambient air temperature and / or the cooling medium temperature downstream of the cooling device, such that the second temperature of the cooling medium is higher than the ambient temperature and / or the cooling medium temperature downstream of the cooling device. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The invention and its many advantages will be described in more detail below with reference to the accompanying drawings, which show some non-limiting embodiments for illustrative purposes and in which

[0056] Figure 1 shows a portion of a wind turbine with a cooling device,

[0057] Figure 2 shows a schematic known cooling system,

[0058] Figure 3 An embodiment of the present invention is shown.

[0059] Figure 4 Another embodiment of the present invention is shown, and

[0060] Figure 5 A further embodiment of the present invention is shown.

[0061] All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested. DETAILED DESCRIPTION

[0062] Figure 1 A perspective view of a wind turbine 100 is shown, including a nacelle 101 and a cooling device 10. Nacelle 101 sits atop a tower 102 and has a front facing a hub 7, into which a plurality of rotor blades 8 (typically three blades) are secured. Nacelle 101 can house a generator and other components used to drive the process of converting wind energy into electricity—also known as a drive train. When generating electricity, the drive train generates significant heat, which, as described above, can lead to lower efficiency in the conversion process.

[0063] To cool components and other parts of the nacelle, a cooling device 10 is arranged outside the nacelle 101. Wind flowing along the longitudinal extension e of the nacelle 101 passes through at least one cooling zone of the cooling device 10, thereby cooling the cooling medium circulating within the cooling device. The cooled cooling medium primarily exchanges heat with the components or equipment to be cooled. The nacelle 101 has a first face 5 including a longitudinal extension e oriented in the wind direction w. The cooling device 10 can be positioned at the front, center, or rear of the nacelle.

[0064] The present invention will mainly be described in connection with upwind wind turbines, i.e. wind turbines in which the nacelle 101 is placed downwind of the wind turbine blades 8. However, the present invention can also be advantageously implemented in downwind wind turbines, i.e. wind turbines in which the nacelle is placed upwind of the wind turbine blades.

[0065] The cooling device 10 can be either an active cooling device or a passive cooling device. The cooling device 10 utilizes wind, where wind flows around the nacelle of the wind turbine to cool a plurality of fluid pipes through which a cooling medium circulates, thereby reducing the temperature of the cooling medium. Additionally, a fan or similar device can be connected to the cooling device 10 to ensure adequate wind flow to the cooling device under all conditions, i.e., an active cooling device.

[0066] exist Figure 2 , a known cooling system is shown. A cooling medium is configured to circulate in a cooling circuit 11, which is fluidically connected to a component 12 and a cooling device 10. Cooling device 10 is disposed on an outer surface of a nacelle 101 and is exposed to environmental conditions, such as wind flow and ambient air temperature outside nacelle 101. As described above, the cooling medium is cooled in cooling device 10 by the wind flow passing through cooling device 10, and the cooling medium circulates from cooling device 10 to component 12. The cooling medium is circulated in cooling circuit 11 by means of a pump unit 13.

[0067] When the cooling medium reaches the component 12, i.e. the heat generating component, the component will dissipate heat energy, causing the temperature in the cooling medium to rise. The components 12 have different sizes and waste heat generation rates and can be connected in parallel or in series with each other, such as Figure 2Here, a total of five components 12 are shown, but the number can be significantly larger or smaller, depending on the wind turbine. These components 12 typically, but not exclusively, include mechanical and electronic equipment such as bearings, brakes, gearboxes, generators, pumps, hydraulic systems, fans, transformers, and converters.

[0068] The pump unit 13 ensures a continuous flow of the cooling medium in the cooling system and conveys the heated cooling medium from the component 12 to the externally mounted cooling device 10, which is exposed to ambient conditions. The outside wind cools the cooling medium, which then returns to the nacelle 101. Thereafter, the cooling medium is directed back to the component 12 and the cycle repeats itself.

[0069] Considering the cooling cycle in terms of the temperature distribution of the cooling medium, please consider Figure 2 Points 1 to 4 in the cooling system. The cooling medium temperature at point 1 (the outlet of the last component) of a cooling system operating according to today's design may be 55°C. Assuming that well-insulated pipes transport the cooling medium in the cooling circuit 11 to the cooling device 10, the temperature of the cooling medium will remain unchanged at the inlet of the cooling device 10 at point 2. Wind at the temperature of the ambient air (for example 20°C) passes through the cooling device 10 located outside and cools the cooling medium to, for example, 40°C at point 3. From here, the cooling medium is pumped to the component 12 at this temperature, and since it does not pass through other equipment or components on its way, it is kept at Figure 2 In the design shown, the temperature at point 4 will be essentially the same as the temperature at point 3.

[0070] In the example above, the cooling medium at the inlet of the cooling device 10 has a temperature difference of 55°C - 20°C = 35°C from the ambient air, which allows a certain amount of energy to be dissipated from the cooling device to the ambient air. In this example, this amount of energy causes the temperature of the cooling medium to drop to 40°C.

[0071] However, if the wind turbine is placed in a hot climate with an ambient air temperature of 30°C instead of 20°C, the temperature difference becomes 25°C, which will cause a decrease in the amount of heat transferred out of the cooling device, and therefore out of the cooling medium. In this situation, the outlet temperature of cooling device 10 may be 45°C instead of 40°C, the desired inlet temperature for the components. If the ambient air temperature rises further, the energy transfer will decrease further, and the outlet temperature of the cooling device will increase accordingly. This trend continues until the ambient air temperature equals the inlet temperature at the cooling device and the energy transfer becomes zero, causing the inlet and outlet temperatures of the cooling device to be equal.

[0072] The problem of increased ambient air temperature is the main motivation for the present invention.

[0073] exist Figure 3FIG. 1 shows an embodiment of a wind turbine cooling system 110 of the present invention. The design of the cooling circuit 11 is similar to Figure 2 The design shown in and described above. Figure 3 Different components and elements are also present in the illustrated embodiments.

[0074] According to the present invention, the first temperature-changing section 14 is fluidly connected to the cooling circuit 11 upstream of the cooling device 10, and the first temperature-changing section 14 is configured to heat the cooling medium before entering the cooling device 10. In addition, the second temperature-changing section 15 is fluidly connected to the cooling circuit 11 downstream of the cooling device 10, and the second temperature-changing section 15 is configured to cool the cooling medium after the cooling medium has left the cooling device 10.

[0075] The wind turbine cooling system includes a first valve unit 16 configured to fluidically connect the component 12 with the cooling device 10 and / or the first temperature change section 14. Furthermore, the wind turbine cooling system includes a second valve unit 20 configured to fluidically connect the cooling device 10 with the component 12 and / or the second temperature change section 15.

[0076] In this embodiment, the cooling medium is fluidly connected to the first temperature change section 14 via a first valve unit 16 having an inlet 17, a first outlet 18 and a second outlet 19, and the first valve unit 16 is configured to have a first position in which the inlet 17 is fluidly connected to the first outlet 18 and a second position in which the inlet 17 is fluidly connected to the second outlet 19, and wherein the inlet 17 is fluidly connected to the component 12, the first outlet 18 is fluidly connected to the cooling device 10, and the second outlet 19 is fluidly connected to the first temperature change section 14.

[0077] In addition, the cooling medium is fluidly connected to the second temperature change device 15 via a second valve unit 20 having an inlet 21, a first outlet 22 and a second outlet 23, and the second valve unit 20 is configured to have a first position in which the inlet 21 is fluidly connected to the first outlet 22 and a second position in which the inlet 21 is fluidly connected to the second outlet 23, and wherein the inlet 21 is fluidly connected to the cooling device 10, the first outlet 22 is fluidly connected to the component 12, and the second outlet 23 is fluidly connected to the second temperature change section 15.

[0078] The first valve unit 16 and the second valve unit 20 may be, for example, modulating solenoid valves, three-way valves, or the like.

[0079] The first temperature change section 14 and the second temperature change section 15 are shown as separate parts in this embodiment. However, they can be operatively connected, for example, via the control unit 24.

[0080] Both temperature-changing sections 14 , 15 may include a heat exchanger configured to heat the cooling medium in the first temperature-changing section 14 and cool the cooling medium in the second temperature-changing section 15 .

[0081] The ambient air temperature may be measured by an ambient air temperature sensor 25 .

[0082] Additional temperature sensors may be arranged in connection with cooling circuit 11 to measure the temperature of the cooling medium at various locations, for example, at points 1-4. Some of the measurement points are shown outside the nacelle, but all measurement points may be arranged inside the nacelle, or some may be arranged inside the nacelle and others outside. Advantageously, at least a first temperature sensor is arranged to measure the temperature of the cooling medium downstream of the component, and at least a second temperature sensor may be arranged to measure the temperature of the cooling medium downstream of the cooling device.

[0083] The temperature sensor, the ambient air temperature sensor 25 , the first valve unit 16 , the second valve unit 20 , the first temperature change zone 14 , and the second temperature change zone 15 may all be operatively connected to the control unit 24 .

[0084] For example, the second temperature sensor can measure the temperature of the cooling medium downstream of the cooling device 10. The measured temperature can be transmitted to the control unit 24, and the control unit 24 controls the first temperature changing section based on the measured temperature so that the cooling medium can be heated or cooled before entering the cooling device, thereby providing an optimal cooling system under varying ambient temperatures, especially in warm climates.

[0085] exist Figure 4 In FIG. 1 , another embodiment of a wind turbine cooling system 110 of the present invention is shown. The design of the cooling circuit 11 is similar to that of FIG. Figure 2 The design shown in and described above. Figure 4 Different components and elements are also present in the illustrated embodiments.

[0086] In this embodiment, the first temperature-changing section 14 is fluidly connected to the cooling circuit 11 upstream of the cooling device 10, and the first temperature-changing section 14 is configured to heat the cooling medium before the cooling medium enters the cooling device 10. In addition, the second temperature-changing section 15 is fluidly connected to the cooling circuit 11 downstream of the cooling device 10, and the second temperature-changing section 15 is configured to cool the cooling medium after the cooling medium leaves the cooling device 10.

[0087] Furthermore, the first temperature change section 14 and the second temperature change section 15 are integrated into the temperature change device 26 .

[0088] In the same manner as described above, the cooling medium is fluidly connected to the first temperature change section 14 via a first valve unit 16 having an inlet 17, a first outlet 18 and a second outlet 19, the first valve unit 16 being configured to have a first position in which the inlet 17 is fluidly connected to the first outlet 18 and a second position in which the inlet 17 is fluidly connected to the second outlet 19, and in which the inlet 17 is fluidly connected to the component 12, the first outlet 18 is fluidly connected to the cooling device 10, and the second outlet 19 is fluidly connected to the first temperature change section 14.

[0089] Moreover, the cooling medium is fluidly connected to the second temperature change device 15 via a second valve unit 20 having an inlet 21, a first outlet 22 and a second outlet 23, and the second valve unit 20 is configured to have a first position in which the inlet 21 is fluidly connected to the first outlet 22 and a second position in which the inlet 21 is fluidly connected to the second outlet 23, and wherein the inlet 21 is fluidly connected to the cooling device 10, the first outlet 22 is fluidly connected to the component 12, and the second outlet 23 is fluidly connected to the second temperature change section 15.

[0090] In this embodiment, the first valve unit 16 and the second valve unit 20 may also be modulating solenoid valves, three-way valves, etc.

[0091] In the present embodiment, the first temperature changing section 14 and the second temperature changing section 15 are operatively connected, for example, via the control unit 24. However, each section may be controlled independently of the other.

[0092] In another embodiment, the first temperature changing section 14 and the second temperature changing section 15 can be fluidly connected to the cooling circuit so that the cooling medium downstream of the component can be directly circulated into the first temperature changing section before the cooling medium is circulated to the cooling device, and the cooling medium will be directly circulated into the second temperature changing section downstream of the cooling device in the same manner before the cooling medium is circulated to the component. In this embodiment, the first valve unit and the second valve unit can be excluded from the wind turbine cooling system.

[0093] The control unit 24 is configured to change the temperature of the cooling medium upstream of the cooling device 10 relative to the measured ambient air temperature and / or the measured temperature of the cooling medium downstream of the cooling device, such that the temperature of the cooling medium upstream of the cooling device 10 is higher than the ambient air temperature and / or the measured temperature of the cooling medium downstream of the cooling device. This will be described further below.

[0094] In this embodiment, the temperature changing device 26 is a refrigeration system, such as a refrigeration device 27. The refrigeration device 27 is configured to remove heat from the cooling medium via a vapor compression or absorption refrigeration cycle.

[0095] In the present embodiment, the temperature level corresponds to the pressure level at which the working medium provided in the temperature change device 26, i.e., the refrigeration device 27, undergoes a phase change by means of the compressor 28. The cooling medium from the cooling device 10 is fluidically connected to the second temperature change section 15 via a heat exchanger so that the cooling medium can be further cooled to a lower temperature before it reaches the component 12.

[0096] The second temperature changing section 15 is configured to reduce the temperature of the cooling medium by absorbing heat from the working medium, and the temperature changing device 26 , ie, the refrigeration device 27 , is configured to transport and dissipate the heat to the first temperature changing section 14 of the temperature changing device 26 .

[0097] The cooling medium from the component 12 is fluidly connected to the first temperature changing section 14 where the cooling medium receives dissipated energy via a heat exchanger at a higher temperature and causes the cooling medium to be heated before it reaches the cooling device 10 .

[0098] exist Figure 5 In FIG. 1 , another embodiment of the wind turbine cooling system 110 of the present invention is shown. The design of the cooling circuit 11 is similar to Figure 4 The design shown and described above. Figure 5 Different components and elements are also present in the illustrated embodiments.

[0099] In this embodiment, the first temperature changing section 14 is fluidly connected to the cooling circuit 11 upstream of the cooling device 10, and the first temperature changing section 14 is configured to heat the cooling medium before the cooling medium enters the cooling device 10. In addition, the second temperature changing section 15 is fluidly connected to the cooling circuit 11 downstream of the cooling device 10, and the second temperature changing section 15 is configured to cool the cooling medium after the cooling medium has left the cooling device 10.

[0100] In addition, the first temperature changing section 14 and the second temperature changing section 15 are integrated into the temperature changing device 26. In this embodiment, the temperature changing device 26 can also be a refrigeration system, for example, as described above in conjunction with Figure 4 Refrigeration device 27 is described. Refrigeration device 27 is configured to remove heat from the cooling medium via a vapor compression or absorption refrigeration cycle.

[0101] In this embodiment, the first valve unit 16 includes a first valve 50 having a first valve position in which the component 12 is fluidly connected to the cooling device 10 and a second valve position in which fluid communication through the first valve 50 is closed, and a second valve 51 having a first valve position in which the component 12 is fluidly connected to the first temperature changing section 14 and a second valve position in which fluid communication through the second valve 51 is closed. Both the first valve 50 and the second valve 51 can have intermediate positions between the first valve position and the second valve position, so that a varying flow rate through the first valve 50 or the second valve 51 can be provided depending on the situation.

[0102] In addition, in this embodiment, the second valve unit 20 includes a first valve 52 having a first valve position in which the cooling device 10 is fluidly connected to the component 12 and a second valve position in which the fluid communication through the first valve 52 is closed, and a second valve 53 having a first valve position in which the cooling device 10 is fluidly connected to the second temperature changing section 15 and a second valve position in which the fluid communication through the second valve 53 is closed. As described above, both the first valve 52 and the second valve 53 can have intermediate positions between the first valve position and the second valve position, so that a varying flow rate through the first valve 52 or the second valve 53 can be provided depending on the situation.

[0103] In one embodiment, the first valve and the second valve are operatively connected such that, for example, when the first valve is in the first valve position, the second valve can be in the second valve position, and vice versa.

[0104] The first valve and the second valve may be shut-off valves, two-way valves, throttle valves or the like.

[0105] exist Figure 3-5 In the present invention, the cooling system layout is presented as having only a single cooling medium circuit. However, there can be many variations of this cooling system design, some of the most common being two completely independent cooling circuits or two coupled cooling circuits. In the first mentioned cooling system configuration, the cooling medium will flow through a designated part of the cooling device, for example half of the total cooling area, and then be pumped to a number of components. Similarly, the other cooling circuit will pass through the remaining part of the cooling device and the remaining number of components. The case of two or more coupled cooling circuits is similar to the separate case, but here the cooling circuits share the same cooling medium and pumping unit. The delivery of the cooling medium in the cooling system will then be reduced to, for example, half of the cooling device and some components next to it, and then returned to the rest of the cooling device and finally to some of the remaining components. In these mentioned cases, the temperature change device can be as Figure 4It is shown as a single piece, but with two first temperature changing sections upstream of the cooling device and two temperature changing sections downstream of the cooling device, to cover two cooling circuits or alternatively to install two cooling devices instead of one.

[0106] According to the present invention, combined with Figure 2 Compared to the described example, ie the prior art solution, the temperature varying sections 14 , 15 will change the temperature in the cooling system.

[0107] For example, in Figure 3-5 The cooling medium temperature at midpoint 1 is 55°C. When the first temperature-varying section 14 is activated and the cooling medium flow is directed through it, the cooling medium absorbs thermal energy, causing the temperature to rise to, for example, 65°C at point 2. After the cooling medium is cooled to, for example, 50°C at point 3, for example, by heat exchange with air passing through the cooling device 10, the second valve 20 can direct the cooling medium to flow through the second temperature-varying section 15, where the temperature of the cooling medium is further reduced to, for example, 40°C at point 4. From this point on, the cooling medium reaches the desired design temperature before entering the heat-generating components.

[0108] Therefore, with the first and second temperature-varying zones 14 and 15 activated, the temperature of the cooling medium at points 1 and 4 (the outlet and inlet of the component 12) remains the same as above. This means that by adding the first and second temperature-varying zones 14 and 15 to the cooling circuit 11, no change in the conditions of the component 12 occurs.

[0109] Furthermore, by adding the first and second temperature varying sections 14, 15, the temperature of the cooling medium is varied in the cooling system 110, and the cooling device 10 is able to maintain the desired heat dissipation to the surrounding environment as the cooling medium warms up at the inlet of the cooling device 10. This restores the desired temperature difference between the cooling medium and the ambient conditions when the wind turbine is located in a hot climate.

[0110] In addition, the general temperature range for activating the first and second temperature changing sections 14, 15 in the cooling system 110 is preferably expected to be:

[0111] Point 1: 40-65℃

[0112] Point 2: 45-80℃

[0113] Point 3: 35-55℃

[0114] Point 4: 30-50℃

[0115] The temperature at point 1 may be a first temperature, the temperature at point 2 may be a second temperature, the temperature at point 3 may be a third temperature, and the temperature at point 4 may be a fourth temperature.

[0116] Thus, the first temperature may be between 40-65°C, the second temperature may be between 45-80°C, the third temperature may be between 35-55°C, and the fourth temperature may be between 30-50°C.

[0117] The overall purpose of a wind turbine cooling system is to achieve the required temperature at point 4, ie to provide cooling fluid / coolant at the desired temperature at the entry point of the component to be cooled.

[0118] Due to its different configurations or modes, the present invention has various benefits and can solve different problems in the field of wind turbine design.

[0119] Thus, by implementing the present invention, it is possible to enhance cooling of components of a wind turbine at elevated ambient air temperatures. Furthermore, due to the additional cooling capacity of the cooling system according to the present invention, it is possible to increase the megawatt rating of the wind turbine and / or increase the power density of the wind turbine, i.e., shrink the components.

[0120] The invention stems from the fact that the first temperature changing section and the second temperature changing section provide access to additional cooling of the cooling system at relatively low energy cost.

[0121] As mentioned above, additional cooling can address cooling issues at high ambient air temperatures, but it can also have additional advantages even when the ambient air temperature is not very high.

[0122] By enhancing or increasing the ability to cool the wind turbine in these situations, the present invention ensures adequate cooling even in adverse temperature conditions with high ambient air temperatures.

[0123] The present invention improves the performance of existing cooling systems for wind turbines without the components to be cooled receiving anything other than a cooling medium within a normally acceptable temperature range and without making any changes to the cooling apparatus or adding features or equipment to the cooling apparatus itself.

[0124] The present invention utilizes the aforementioned change in the temperature difference between the cooling medium and the ambient air temperature by integrating the first temperature changing section 14 and the second temperature changing section 15 into the cooling circuit 11 .

[0125] Furthermore, the present invention allows for different utilization of cooling system 110 in situations where ambient air temperatures are not very high. The existing cooling system can provide the cooling required for normal system operation. If the cooling performance of the first and second temperature-variable sections 14, 15 is increased in this case, the temperature of the cooling medium reaching the components is still reduced, meaning that more heat can be dissipated within the components before their operating temperatures return to the levels of normal turbine operation without the first and second temperature-variable sections 14, 15. Consequently, for example, the wind turbine's drive train can withstand greater loads, and the resulting corresponding heat loads, than would normally be the case if the wind turbine's megawatt rating were increased.

[0126] Another advantage of the present invention is related to the so-called power density, which is a measure of the power output of a component in relation to its size and is expressed in units of MW / m 3 be evaluated. In existing designs of wind turbines, the trend towards making larger and larger wind turbines is clear and has been so for many years. However, in order to keep the nacelle and the components in the nacelle to a manageable size and weight, the wind power industry wants to increase the power density of the components as the size of the wind turbine increases. As mentioned above, if the first temperature variable section 14 and the second temperature variable section 15 are enabled under conditions of non-critical ambient air temperature, it can still produce a cooling medium for further cooling of the heat-generating components. However, if the load of the wind turbine remains unchanged, the size of the critical components can be reduced, which can also reduce the cost of the wind turbine as a whole. For example, if the number of copper windings of a generator is reduced but the current passing through them remains the same, the resistance of the copper windings increases. This will result in more waste heat from the component (i.e. the generator), which the cooling system must remove. Again, due to the enhanced cooling introduced by the present invention, the increase in heat load is not a problem.

[0127] Another popular parameter in wind turbine system design is redundancy. This ensures that the wind turbine can continue to operate at full or partial load in the event of a failure in a critical component. In this case, an identical or alternate component will be used, ignoring the inoperative component.

[0128] Integrating the present invention into an existing cooling system also introduces redundancy. In the unlikely event of a failure of the first and second temperature-variable sections 14, 15, or during maintenance, the wind turbine, according to current designs, will continue to operate normally. If ambient air temperatures become excessively high, the turbine will reduce its power output and derate to avoid overheating. In other words, the wind turbine faces the same situation as current designs without the present invention.

[0129] Additionally, for example, the maximum load of the transmission system will be restored to the original level set in today's design, and the megawatt rating will also be restored to the default value.

[0130] Common to all cases is that the wind turbine will continue to operate in the event of a failure of the first temperature varying section 14 and the second temperature varying section 15 .

[0131] The present invention provides improved cooling performance with a range of interesting technical features and potential market impact.

[0132] With regard to enhanced cooling in warm climates, a large proportion of offshore wind turbines will be erected in temperate or tropical regions around the world in the coming years.

[0133] Offshore wind turbines are generally larger in size and rated power output, but have lower sales volumes compared to onshore wind turbines, which are smaller and have lower megawatt ratings.

[0134] In the onshore market, some of the largest current markets (such as the United States, Brazil, India and China) and some new, fast-growing markets (such as Australia, Mexico, the Middle East and Africa) have very warm climates. Therefore, it is expected that a large number of onshore turbines will be installed in continents with warm climates in the future.

[0135] Thus, the present invention is highly relevant to both future onshore and offshore markets.

[0136] Furthermore, when integrated into the temperature changing device 26, the first temperature changing section 14 and the second temperature changing section 15 can be retrofitted on existing wind turbines. For example, the temperature changing device 26 can be arranged inside the nacelle, such as Figure 3-5 As shown, however, in another embodiment not shown, the temperature changing device 26 may be arranged outside the nacelle, or for example in a tower.

[0137] In addition, the heat generating components are preferably Figure 3-5 The arrangement is shown inside the nacelle, however, in embodiments not shown, the components may be arranged outside the nacelle, in the nacelle and / or in the vicinity of the wind turbine, for example on or near a tower.

[0138] For an embodiment in which the component has a preferred inlet temperature of approximately 40°C, the ratio between the heat dissipation of the component to be cooled and the volume of the flow through the component is considered. This ratio depends on the constant properties of the cooling fluid, which can be R718 (water), at, for example, 40°C. The ratio is calculated as the heat loss (in kW) in the cooling fluid divided by the flow rate (in liters / minute) of the cooling fluid / coolant. In an embodiment using R718 as the cooling fluid, the ratio can be equal to or less than 0.75 [kW] / [L / min]. In an embodiment using a mixed or different cooling fluid, the ratio can be 0.5-1 [kW] / [l / min].

[0139] Examples of using ratios:

[0140] A component, such as a wind turbine's generator, needs to dissipate 400 kW of heat to a coolant. For the cooling system to remove the necessary heat, the flow rate of the cooling fluid through the generator needs to be 535 L / min for R718, calculated as 400 kW / 0.75 kW / l / min. It will be appreciated that different cooling fluids will result in different required flow rates.

[0141] Although the invention has been described above in conjunction with preferred embodiments thereof, it is obvious to a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.

Claims

1. A wind turbine cooling system (110) configured to cool a component (12) of a wind turbine (100), the wind turbine having a nacelle (101), the wind turbine cooling system (110) comprising a cooling medium configured to circulate in a cooling circuit (11) which fluidically connects the component (12) and the cooling device (10), - the cooling device (10) is arranged on an outer surface of the nacelle (101) and is exposed to ambient conditions, - the cooling medium is cooled in the cooling device (10) by the wind flow passing through the cooling device (10), - the cooling medium circulates from the cooling device (10) to the component (12), in, A first temperature-changing section (14) is fluidically connected to the cooling circuit (11) upstream of the cooling device (10), and the first temperature-changing section (14) is configured to heat the cooling medium before entering the cooling device (10), and A second temperature-changing section (15) is fluidically connected to the cooling circuit (11) downstream of the cooling device (10), and the second temperature-changing section (15) is configured to cool the cooling medium after the cooling medium has left the cooling device (10).

2. The wind turbine cooling system (110) of claim 1, wherein: The first temperature changing section (14) and the second temperature changing section (15) are integrated into a temperature changing device (26).

3. The wind turbine cooling system (110) according to claim 1 or 2, wherein: The first temperature-changing section (14) and the second temperature-changing section (15) are operatively connected.

4. The wind turbine cooling system (110) according to claim 1 or 2, further comprising a first valve unit (16) configured to fluidically connect the component with the cooling device (10) and / or the first temperature changing section (14).

5. The wind turbine cooling system (110) according to claim 1 or 2, further comprising a second valve unit (20) configured to fluidically connect the cooling device (10) with the component and / or the second temperature changing section (15).

6. The wind turbine cooling system (110) according to claim 1 or 2, further comprising an ambient air temperature sensor (25) for measuring the ambient air temperature and / or a second temperature sensor configured to measure the temperature of the cooling medium downstream of the cooling device.

7. The wind turbine cooling system (110) of claim 1 or 2, further comprising a first temperature sensor configured to measure a temperature of the cooling medium downstream of the component (12).

8. The wind turbine cooling system (110) according to claim 1 or 2, further comprising a control unit (24), the control unit (24) being operatively connected to the first temperature variable section (14), the second temperature variable section (15), an ambient air temperature sensor (25) for measuring the ambient air temperature, a first temperature sensor configured to measure the temperature of the cooling medium downstream of the component (12), a second temperature sensor configured to measure the temperature of the cooling medium downstream of the cooling device, a first valve unit (16) configured to fluidically connect the component with the cooling device (10) and / or the first temperature variable section (14), and / or a second valve unit (20) configured to fluidically connect the cooling device (10) with the component and / or the second temperature variable section (15).

9. The wind turbine cooling system (110) of claim 8, wherein: The control unit (24) is configured to change the temperature of the cooling medium upstream of the cooling device (10) in relation to the determined ambient air temperature so that the temperature of the cooling medium upstream of the cooling device (10) is higher than the ambient air temperature.

10. The wind turbine cooling system (110) of claim 2, wherein: The temperature changing device (26) is a refrigeration system.

11. The wind turbine cooling system (110) according to claim 2 or 10, wherein: The temperature level corresponds to the pressure level at which the working medium provided in the temperature changing device (26) by means of the compressor (28) undergoes a phase change.

12. The wind turbine cooling system (110) of claim 11, wherein: The cooling medium from the cooling device (10) is fluidically connected to the second temperature-changing section (15) via a heat exchanger, so that the cooling medium can be further cooled to a lower temperature before it reaches the component (12).

13. The wind turbine cooling system (110) of claim 11, wherein: The second temperature-changing section (15) is configured to reduce the temperature of the cooling medium by absorbing heat in the working medium, and the temperature-changing device (26) is configured to transport and dissipate the heat to the first temperature-changing section (14) of the temperature-changing device (26).

14. The wind turbine cooling system (110) of claim 12, wherein: The second temperature-changing section (15) is configured to reduce the temperature of the cooling medium by absorbing heat in the working medium, and the temperature-changing device (26) is configured to transport and dissipate the heat to the first temperature-changing section (14) of the temperature-changing device (26).

15. The wind turbine cooling system (110) according to claim 13 or 14, wherein: Cooling medium from the component (12) is fluidly connected to the first temperature changing section (14) where it receives dissipated energy at a higher temperature via a heat exchanger, causing the cooling medium to heat up before it reaches the cooling device (10).

16. The wind turbine cooling system (110) of claim 1, wherein: The environmental conditions include wind flow and ambient air temperature outside the nacelle (101).

17. The wind turbine cooling system (110) of claim 10, wherein: The refrigeration system comprises a refrigeration device (27).

18. A method of cooling one or more components (12) of a wind turbine (100) by means of a wind turbine cooling system (110) according to any one of claims 1 to 17, comprising: - measuring a first temperature of the cooling medium downstream of said component (12), - raising the temperature of the cooling medium upstream of the cooling device (10) to a second temperature, - reducing the temperature of the cooling medium in the cooling device (10) to a third temperature, and - reducing the temperature of the cooling medium downstream of the cooling device (10) to a fourth temperature lower than the third temperature.

19. The cooling method according to claim 18, further comprising: - measuring the ambient air temperature and / or the temperature of the cooling medium downstream of said cooling device, - varying the second temperature of the cooling medium upstream of the cooling device (10) with respect to the determined ambient air temperature and / or the cooling medium temperature downstream of the cooling device, such that the second temperature of the cooling medium is higher than the ambient air temperature and / or the cooling medium temperature downstream of the cooling device.

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