Method for operating heat exchanger and device comprising heat exchanger
By distinguishing photographs of visible wavelength ranges and invisible wavelength ranges, combining image evaluation software and machine learning, the problem of low defrost accuracy of heat transfer is solved, and the efficient and safe operation of heat transfer is achieved.
Patent Information
- Application Number
- CN202380039212.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-27
- Filing Date
- 2023-05-25
- Publication Date
- 2024-12-31
AI Technical Summary
The prior art has low accuracy when defrosting in heat transfer devices, which may lead to premature or late defrosting, affecting system operation, and existing methods such as infrared camera monitoring have problems with inaccurate results.
By distinguishing between visible wavelength range photographic photos used to determine defrost time and invisible wavelength range photographic photos used to control the defrost process, combining image evaluation software and machine learning algorithms, automate the determination of defrost time and optimize the defrost process, ensuring that The heat transfer is efficient and safe to operate.
Accurate determination of defrost time and optimized process control are achieved, ensuring efficient operation of the heat transfer device and avoiding unnecessary heating energy consumption and system failures.
Smart Images
Figure CN119234114A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for operating a heat exchanger and to a device comprising a heat exchanger. Background Art
[0002] Heat exchangers are used to remove heat from a system to be cooled or to introduce heat into a system to be heated. In the field of cooling technology, such heat exchangers are used to remove heat from a volume to be cooled, in which the cooling medium changes from the liquid phase to the gas phase, wherein the heat exchanger is used as an evaporator. Similarly, heat exchangers in the field of heating technology can be used to receive ambient heat from the outside air in order to provide heat for the building to be heated in cooperation with a heat pump. Conversely, such heat exchangers can also be used as liquefiers or return coolers in order to release heat to the environment.
[0003] Independent of the respective use case, it is essential for the reliable and error-free function of the heat exchanger that the heat transfer between the heat exchanger and its environment is not limited by disruptive influences which isolate the heat exchanger from the environment. Such disruptive influences are, for example, contamination of the heat exchanger or ice which can accumulate, for example, between the leaves or leaf groups of the heat exchanger.
[0004] Heat exchangers often have blades or blade groups in order to provide the largest possible surface available for heat transfer while keeping the overall size small. In the actual operation of such heat exchangers, it may happen that moisture from the environment of the blades is deposited on the surface of the blades and causes ice to form on these surfaces and in the gaps formed between the blades. Due to the insulating effect of these ice formations, the heat transfer between the environment of the heat exchanger and its blades or the corresponding liquid guided in the heat exchanger is affected. In addition, the air flow of the heat exchanger is deteriorated, wherein on the one hand, the pressure loss increases and on the other hand, the power is reduced because less air flows through the heat exchanger. In this state, the heat exchanger may no longer provide the required cooling power or heating power. This can lead to a loss of cooling quality or failure of the device to be cooled. These ice formations can further lead to damage to the components of the heat exchanger.
[0005] In order to remove ice, it is known to defrost the heat exchanger with the aid of a heating device. Such defrosting should be carried out as efficiently as possible. If defrosting is performed too often or at too long intervals, unnecessarily much heating energy is introduced into the volume to be cooled, for example, which then has to be transported away again with the aid of the heat exchanger in order to maintain or adjust the set cooling temperature. If defrosting is performed too infrequently or at too short intervals, the defrosting is not effective and affects the proper functioning of the relevant system. Known methods for defrosting are, for example, electric defrosting, hot gas defrosting, hot brine defrosting and water or air defrosting.
[0006] Document US 11,221,173 B2 describes a device and a method for defrosting a heat exchanger, wherein icing is monitored by means of an infrared camera and defrosting is controlled by means of an infrared camera. In this case, icing is evaluated by means of the brightness in the image of the infrared camera, wherein high brightness is associated with small icing and low brightness is associated with more intense icing. The disadvantage here is that the infrared camera is only limitedly suitable for monitoring icing and for determining the defrosting time and provides inaccurate results. This can result in defrosting too early or too late.
[0007] Document KR 102041145 B1 relates to a device and a method for defrosting a heat exchanger, wherein icing is monitored by means of a camera and defrosting is controlled by means of a camera. A disadvantage here is that conventional cameras are only limitedly suitable for controlling defrosting and for determining the end of defrosting and provide inaccurate results. This may result in defrosting that is too long or too short. Summary of the invention
[0008] Against this background, the object of the present invention is to specify a method for operating a heat exchanger and a device comprising a heat exchanger which in particular allow efficient defrosting and process-safe operation of the heat exchanger.
[0009] The above-mentioned technical problems are solved by the independent claims, respectively. Further embodiments of the invention are apparent from the dependent claims and the following description.
[0010] According to a first aspect, the present invention relates to a method, comprising the method steps of: operating a heat exchanger; detecting an icing state of the heat exchanger and determining a defrosting time of the heat exchanger by means of an evaluation of a first photograph of the heat exchanger; starting a defrosting process of the heat exchanger by means of a heating device at the defrosting time and controlling the defrosting process by means of an evaluation of a second photograph of the heat exchanger; wherein the evaluation of the first photograph is different from the evaluation of the second photograph.
[0011] By distinguishing between the evaluation for determining the defrost moment and the evaluation for controlling the defrost process, it is possible to improve not only the determination of the defrost moment but also the control of the defrost process. This is because the respective tasks on which the determination of the defrost moment and the control of the defrost process are based are very different. Thus, the purpose of the determination of the defrost moment and the evaluation on which the determination of the defrost moment is based is to observe and evaluate the state, i.e. the icing state of the heat transferer, while the purpose of the control of the defrost process is to use the heating device for deicing the heat transferer as efficiently as possible. The deviating construction of the evaluation of the first photograph and the evaluation of the second photograph thus independently of each other enables not only the optimization of the determination of the defrost moment but also the optimization of the control of the defrost process without them influencing or hindering each other. In this way, efficient defrosting of the heat transferer and safe operation of the process can be ensured.
[0012] It can be arranged that the first photograph is a photograph in a visible wavelength range.
[0013] It can be provided that a light source is provided for illuminating the heat exchanger for constructing a photograph in the visible wavelength range. Such a light source can be a flashlight, a light source or the like.
[0014] When the visible wavelength range is mentioned in this context, this is the wavelength range that is discernible by the human eye. In particular, the wavelength range can have a wavelength of approximately 360 nanometers to 830 nanometers, further in particular a wavelength of approximately 400 nanometers to 780 nanometers. The first photograph is therefore in particular similar to a conventional photograph that can be created by a conventional digital camera as is also known from the consumer goods sector.
[0015] The evaluation of the first photograph is therefore in particular an evaluation of a digital photograph in the visible wavelength range.
[0016] It can be set that the first photograph is a photograph of infrared reflection of the heat exchanger. It can be set that the first photograph is an infrared image of the heat exchanger.
[0017] It can be provided that an infrared light source, such as an infrared headlamp or the like, is provided in order to illuminate the heat transmitter in order to construct the photographic infrared picture.
[0018] It can be provided that the evaluation of the first photographs is performed by means of image evaluation software, wherein two or more reference images of the photographs in the visible wavelength range are provided to the image evaluation software and wherein the reference images are compared with the corresponding first photographs by means of the image evaluation software. By means of such a comparison of the first photographs with the reference images, the amount of ice to be detected can be determined by means of the image evaluation software, for example, on the heat exchanger in order to determine the defrosting time. In this way, the determination of the defrosting time can be automated in a simple manner.
[0019] The image evaluation software may be KI-based. KI-based image evaluation has the advantage that the quality of the image evaluation can be increased with increasing data storage. KI-based image evaluation further has the advantage that the evaluation can be applied to different structural sizes and structural types of the heat exchanger, wherein a common database is used.
[0020] When the abbreviation "KI" is used today, it stands for "artificial intelligence" and is a synonym for the related topics "machine learning" and "deep learning".
[0021] In general, the detection of the degree of icing of a heat exchanger and the necessary or unnecessary defrosting to be derived therefrom can be simulated as a classification problem using KI, wherein an imaging function is generated using training data, which uses image data to classify the degree of icing of the heat exchanger as critical or non-critical, so that defrosting is initiated or the heat exchanger can initially continue to be operated without defrosting. It can be provided that the imaging function is further improved using image data processed during operation, so that a "learning" algorithm is involved. In other words, the quality of the imaging function can improve with increasing data storage.
[0022] It can be arranged that a first group of reference images of the photographs in the visible wavelength range show an icing state of the heat transfer device requiring defrosting and a second group of reference images of the photographs in the visible wavelength range show an icing state of the heat transfer device not requiring defrosting, wherein the defrosting moment is defined as long as one or more of the first photographs of the image evaluation software belong to the first group of photographs in the visible wavelength range.
[0023] In particular, the reference images of the photographs in the visible wavelength range can be divided into two or more classes according to the degree of icing to be identified on the reference images. If, for example, an algorithm for machine learning is used here, the reference images divided into various classes can also be referred to as training data for the classifier.
[0024] It can be provided that the reference images have been manually classified by a specialist. Alternatively or additionally, it can be provided that the reference images have been classified based on software, wherein, for example, one or more parameters such as an optically recognizable ice surface, sensor data such as pressure, temperature or the like at the time of receipt of the relevant reference image are taken into account.
[0025] When sensor data are mentioned, this refers to one or more of the following values: temperature data of the environment and / or the refrigerant, in particular the pressure of the refrigerant at the input and output of the heat exchanger; air pressure, in particular the pressure difference between the ambient pressure and the pressure between the blower and the blade arrangement, wherein, for example, the pressure loss on the side of the blade arrangement facing away from the blower is measured.
[0026] For example, it can be provided that the reference image of the photograph in the visible wavelength range is divided into up to 40 classes, in particular into up to 20 classes, and further in particular into up to ten classes, according to the degree of ice formation recognizable in the reference image.
[0027] In particular, it can be provided that the reference images are assigned to the first group or the second group by means of their respective classes, wherein one or more classes are assigned to the first group, wherein one or more classes are assigned to the second group, and the classes assigned to the first group are not assigned to the second group, and vice versa. In particular, it can be provided that two or more classes are assigned to each group.
[0028] By means of the assignment of the reference images with their respective classes to the first group or to the second group, wherein the respective class reflects the degree of icing, a so-called target function can be defined which enables an assignment of the respective first photographs to the first group or to the second group.
[0029] According to another embodiment of the method, it can be provided that the second photograph is a photograph of an invisible wavelength range. When the invisible wavelength range is mentioned, it is especially related to the wavelength range of 780 nm to 1 mm.
[0030] According to another embodiment of the method, it can be provided that the second photograph is a thermal image. Although the thermal image is not referred to as a "photograph" in some parts of the document, a thermal image in the sense of this document is a photograph or a photograph in the invisible wavelength range. A thermal image graphically describes the temperature difference of the relevant object.
[0031] The second photograph may therefore in particular comprise an infrared image and / or a thermal image.
[0032] The evaluation of the first photograph and the evaluation of the second photograph can therefore be distinguished in particular by the fact that the first photograph is a photograph in the visible wavelength range and the second photograph is a photograph in the invisible wavelength range. It has been shown that photographs in the visible wavelength range enable a reliable and precise determination of the defrosting time, while photographs in the invisible wavelength range are particularly suitable for controlling the defrosting process.
[0033] In particular, the invisible wavelength range may be the infrared range.
[0034] The evaluation of the second photographs can be performed with the aid of image evaluation software, wherein two or more reference images of the photographs in the invisible wavelength range are provided to the image evaluation software and a comparison of the reference images with the corresponding second photographs is performed with the aid of the image evaluation software. By comparing such second photographs with the reference images, the image evaluation software can be used to determine, for example, the amount of ice that can be detected on the heat exchanger in order to determine the end of defrosting. In this way, the determination of the end of defrosting can be automated in a simple manner.
[0035] The image evaluation software may be KI-based. KI-based image evaluation has the advantage that the quality of the image evaluation can be increased with increasing data storage. KI-based image evaluation further has the advantage that the evaluation can be applied to different structural sizes and structural types of heat transfer devices, wherein a common database is used.
[0036] According to one design of the method, it can be arranged that a first group of reference images of the photographs in the invisible wavelength range show an icing state of the heat transfer device requiring defrosting, and a second group of reference images of the photographs in the invisible wavelength range show an icing state of the heat transfer device not requiring defrosting, wherein the defrosting process is terminated as long as one or more photographs in the second photographs of the image evaluation software belong to the second group of reference images of the photographs in the invisible wavelength range.
[0037] It can be set to divide the reference image of the photograph in the invisible wavelength range into two or more categories according to the degree of ice formation that can be identified on the reference image. As long as an algorithm for machine learning is used here, for example, the reference images divided into various categories can also be called training data for the classifier.
[0038] Furthermore, it can be provided that the reference images have been manually classified by a specialist. Alternatively or additionally, it can be provided that the reference images have been classified based on software, wherein, for example, one or more parameters such as an optically recognizable ice surface, sensor data such as pressure, temperature or the like at the time of receipt of the relevant reference image are taken into account.
[0039] For example, it can be provided that the reference image of the photograph in the invisible wavelength range is divided into up to 40 classes, in particular into up to 20 classes, and further in particular into up to ten classes, according to the degree of ice formation recognizable in the reference image.
[0040] According to one embodiment of the method, it can be provided that the reference images are assigned to the first group or the second group by means of their respective classes, wherein one or more classes are assigned to the first group, wherein one or more classes are assigned to the second group, wherein classes assigned to the first group are not assigned to the second group, and vice versa. In particular, it can be provided that two or more classes are assigned to each group.
[0041] The evaluation of the second photograph may be a thermal image evaluation of the intensity of the reflection in the invisible wavelength range, wherein the second photograph is a thermal image. Such a thermal image can be recorded, in particular without an external light source, using only the associated sensor of the thermal imaging camera in order to detect the heat signature of the heat exchanger. Conventional digital cameras and also infrared cameras detect reflected light and may rely on additional light sources, whereas thermal imaging cameras are implemented without such light sources.
[0042] Such thermal image evaluation allows targeted control of the heating device in order to ensure reliable defrosting or de-icing on the one hand and to avoid excessive heat input that is not necessary for defrosting on the other hand.
[0043] Additionally, photographs in the visible wavelength range can be used to control the defrosting process. Thus, in one embodiment of the method, in particular both photographs in the visible wavelength range and photographs in the invisible wavelength range are evaluated to control the defrosting process.
[0044] In order to enable a more precise or improved evaluation of the second photograph, it can be provided that the evaluated second photograph is provided in grayscale. Such a presentation in grayscale enables an improved software-based evaluation of the photographs in the invisible wavelength range.
[0045] According to one embodiment of the method, it can be provided that a first time interval between providing and evaluating two consecutive photographs of a first photograph is greater than a second time interval between providing and evaluating two consecutive photographs of a second photograph.
[0046] In particular, it can be provided that the first interval corresponds to more than twice, more than five times, more than ten times, or more than 50 times the second time interval. For example, the first time interval can be 5 minutes, 10 minutes, 15 minutes, 30 minutes, 60 minutes or more, while the second time interval is less than 10 minutes, less than 5 minutes, or less than 1 minute. Since ice formation on the heat exchanger often occurs over longer time intervals in practice, longer time intervals are sufficient for monitoring the ice formation and determining the defrosting time. In contrast, defrosting occurs more quickly by active heat input by means of the heating device, so that shorter time intervals are used for monitoring and controlling such defrosting processes in order to avoid excessive heat input by means of the heating device. The adaptation of the time intervals is used in particular to reduce the amount of data.
[0047] It can be provided that the first time interval is shortened with increasing degree of icing. This ensures that the optimized moment for starting defrosting is not missed.
[0048] In addition to the photographs, sensor data may be used in addition to determine the icing state and / or the defrosting time and / or to control the defrosting process, wherein one or more of the following sensors may be used: temperature sensor, pressure sensor, humidity sensor.
[0049] For example, it can be provided that one or more sensor signals are used for a plausibility test of the result of the evaluation of the first picture and / or the evaluation of the second picture. If the evaluation of the first picture, for example, shows that a critical icing state is reached, which requires defrosting, but the evaluation of one or more sensor signals shows, on the contrary, that a critical icing state is not reached, one or more further evaluations of the first pictures can be carried out in order to check the necessity of defrosting. Alternatively or additionally, a fault message and / or a disturbance message can be output for the above-mentioned cases of contradictory sensor data used for the evaluation of the first picture.
[0050] If the plausibility test is positive, in which both one or more sensor signals and the evaluation of the first image detect a critical icing state, the defrosting time can be determined.
[0051] This principle can be transferred to the determination of the end of defrost in the same way.
[0052] It can be provided that the number of devices for photographic imaging, in particular cameras, for capturing the second photographs is greater than the number of cameras for capturing the first photographs.
[0053] Alternatively or additionally, provision can be made for precisely one device for photographic imaging, in particular a camera, to be provided for recording the first photographic image.
[0054] It can be provided that two or more devices for photographic imaging, in particular cameras, are provided for capturing the second photographic image.
[0055] Alternatively or additionally, it can be provided that a plurality of devices for photographic imaging, in particular cameras, are provided for recording the second photographic image, said devices being arranged distributed along the longitudinal extension of the heat exchanger.
[0056] When it comes to determining the defrosting time, it can be provided, for example, that defrosting starts immediately as soon as the evaluation of the first photograph shows that an icing state requiring defrosting has been reached. Alternatively, it can be provided that the defrosting time is determined for the future by means of the evaluation of the first photograph. In this way, for example, the icing state can be used to infer a future time at which a critical icing state affecting the reliable operation of the heat exchanger is expected to be reached, so that the defrosting time is before this future time. This is because defrosting preferably takes place at a time at which the available power of the heat exchanger is reliably within a predetermined theoretical power range.
[0057] It may be provided that the evaluation of the first photograph and / or the evaluation of the second photograph is performed at least partially with the aid of a server, wherein the control device of the heating device is connected to the server via a wired or wireless data connection.
[0058] Alternatively or additionally, it can be provided that the evaluation of the first photograph and / or the evaluation of the second photograph is performed at least partially with the aid of a computer associated with the heat exchanger and the heating device, wherein a control device of the heating device is connected to the computer via a wired or wireless data connection.
[0059] The evaluation can thus be performed online and / or offline. For example, it can be provided that within the scope of a first setting of the heat exchanger a connection to a server is established in order to carry out a data comparison, while the evaluation is performed locally in continuous operation by means of a computer of the device and, for example, a connection to a server for further data comparison is established only at predetermined time intervals.
[0060] Alternatively, provision can be made for the first photograph and / or the second photograph to be evaluated only by means of the server and for no evaluation to be performed by means of the computer of the device.
[0061] Alternatively, it can be provided that the evaluation of the first photograph and / or the evaluation of the second photograph takes place exclusively by means of the computer of the device and no evaluation takes place by means of the server.
[0062] As a result of the evaluation of the first photograph and / or as a result of the evaluation of the second photograph, a service notification and / or an alarm notification can be generated and output.
[0063] A service notification is here a notification of a maintenance requirement, for example, relating to a heat exchanger and / or a heating device. Such a maintenance requirement should not be considered urgent, so that the heat exchanger and the heating device are not restricted in their functionality at the time of the service notification.
[0064] An alarm notification is a notification about a partial or complete failure or about a heat exchanger and / or heating device no longer functioning as intended. The alarm notification thus signals an urgent, immediate need for processing in order to restore the functionality of the heat exchanger and / or heating device.
[0065] It can be provided that the number of devices for photographic imaging, in particular cameras, for capturing the second photographs is greater than the number of cameras for capturing the first photographs.
[0066] Alternatively or additionally, provision can be made for precisely one device for photographic imaging, in particular a camera, to be provided for recording the first photographic image.
[0067] It can be provided that two or more devices for photographic imaging, in particular cameras, are provided for capturing the second photographic image.
[0068] Alternatively or additionally, it can be provided that a plurality of devices for photographic imaging, in particular cameras, are provided for recording the second photographic image, said devices being arranged distributed along the longitudinal extension of the heat exchanger.
[0069] The method may be a method for cooling a walk-in cooling volume.
[0070] The method may be a method for heating a walk-in heating volume.
[0071] According to a second aspect, the invention relates to a device, which comprises a heat exchanger, wherein the heat exchanger has a pipe that guides a cooling medium, wherein the pipe is connected to a plurality of cooling fins of the heat exchanger and comprises a blower for conveying an air volume flow; comprises a heating device for defrosting the heat exchanger; comprises a device for photographic imaging and comprises a control unit, wherein the control unit is designed to detect the icing state of the heat exchanger and to determine the defrosting time by means of an evaluation of a first photograph, wherein the control unit is designed to control the defrosting process carried out by means of the heating device by means of an evaluation of a second photograph and the evaluation of the first photograph is different from the evaluation of the second photograph.
[0072] By differentiating the evaluation used for determining the defrost moment from the evaluation used for controlling the defrost process, it is possible to improve not only the determination of the defrost moment but also the control of the defrost process. This is because the respective tasks on which the determination of the defrost moment and the control of the defrost process are based are very different. Thus, the purpose of the determination of the defrost moment and the evaluation on which the determination of the defrost moment is based is to observe and evaluate the state, i.e. the icing state of the heat exchanger, while the purpose of the control of the defrost process is to use the heating device for deicing the heat exchanger as efficiently as possible. The deviating configuration of the evaluation of the first photograph and the evaluation of the second photograph thus independently of one another enables not only the optimization of the determination of the defrost moment but also the optimization of the control of the defrost process without them influencing or hindering one another.
[0073] All structural or functional features that have been mentioned above with respect to the specific method can also be the subject matter of the device according to the invention. All method aspects that are described below with respect to the specific device can be the subject matter of the method according to the invention.
[0074] The first photographic image may be a photographic image in the visible wavelength range. This may be the visible wavelength range described above with respect to the method according to the invention.
[0075] The second photographic image may be a photographic image in an invisible wavelength range. The invisible wavelength range described above with respect to the method according to the invention may be involved here.
[0076] It can be configured that the device for photographic imaging has a first camera including a sensor for photographic imaging in the visible wavelength range and a second camera including a sensor for photographic imaging in the invisible wavelength range, or that the device for photographic imaging has a camera for photographic imaging not only in the visible wavelength range but also in the invisible wavelength range.
[0077] In particular, it can be provided that the device for photographic imaging has an infrared camera and / or a thermal imaging camera. The device for photographic imaging can be designed to construct photographic images in the visible wavelength range. The device for photographic imaging can be designed to construct photographic images in the invisible wavelength range and more precisely in the form of infrared images and / or thermal images. The device for photographic imaging can be designed to construct thermal image photographs.
[0078] It can be arranged that the device for photographic imaging is designed to output a photographic picture in the invisible wavelength range in grayscale. In particular, it can be arranged that the control unit is designed to process the second photographic picture provided in grayscale.
[0079] The device may have one or more of the following sensors: temperature sensor, pressure sensor, humidity sensor.
[0080] The device may be a cooling system for cooling a walk-in cooling volume.
[0081] The apparatus may be a heating system for heating a walk-in heating volume.
[0082] When a heating device is mentioned in the present text about a method or an apparatus, this can be, for example, an electric heating device, which has, for example, one or more heating rods, heating spirals or heating circuits. Alternatively or additionally, a heating device can be provided, which guides the fluid through a pipeline. Alternatively or additionally, a heating device can be provided, which has a hot air heating device. The heating device can be realized by reversing the operation of the heat exchanger. The heating device can have a brine defrost. The defrosting can be carried out by electric defrosting, hot gas defrosting, hot brine defrosting, water defrosting or air defrosting. BRIEF DESCRIPTION OF THE DRAWINGS
[0083] Next, the present invention will be further described with reference to the accompanying drawings showing embodiments. Schematically:
[0084] Figure 1 shows a perspective view of the device according to the invention from the front;
[0085] Figure 2 Shown without housing Figure 1 a perspective view of the device from behind;
[0086] Figure 3 Shown is a continuous heating rod Figure 1 Heat transfer device of the equipment;
[0087] Figure 4 A method for producing a heat transfer device comprising a discontinuous heating rod is shown. Figure 1 Heat transfer device of the equipment;
[0088] Figure 5 Show Figure 3 The icing state of the heat transfer device;
[0089] Figure 6 A flow chart of the method according to the invention is shown. DETAILED DESCRIPTION
[0090] Figure 1 An apparatus 2 according to the invention is shown. The apparatus 2 is a cooling system 2. The cooling system 2 can be used, for example, to cool a walk-in cooling volume.
[0091] The cooling system 2 has a housing 4 with a grille 6 for a fan 8 of the cooling system 2. The fan 8 is used to convey air from the environment U along the fins 10 of a heat exchanger 12 of the cooling system 2. Figure 2 The heat exchanger 12 will be described.
[0092] The heat exchanger 12 is located inside the cooling system 2, so that the housing 4 is shown in FIG. Figure 2 The heat exchanger 12 has a plurality of planar or plate-shaped blades 10 which are arranged substantially parallel to one another along the longitudinal extension L of the heat exchanger 12 .
[0093] The blades 10 are penetrated by pipes 14 of a heat exchanger 12, which pipes carry a cooling medium. The blades 10 can also be referred to as cooling blades 10. The cooling blades 10 are connected to the pipes 14 of the heat exchanger 12.
[0094] The device 2 has a heating device 16 with a heating rod 18 for defrosting the heat exchanger 12. The heating rod 18 also penetrates the cooling leaf 10 in the longitudinal direction L and is connected to the cooling leaf 10.
[0095] Figure 3 The cooling sheet 10 of the heat transfer device 12 including the heating rod 18 and the pipe 14 is shown. Figure 3 , the heating rod 18 is arranged in a structure in which the leaf 10 is completely penetrated over the entire length as viewed in the longitudinal direction L.
[0096] Figure 4 An alternative design of a heat exchanger 12' is shown, which can also be used in the device 2 according to the invention. Figure 4 The heat exchanger 12' is distinguished as follows according to Figure 3 A heat transfer device 12 , ie a heating rod 18 ′, is provided which, viewed in the longitudinal direction L, passes through the arrangement of the leaf 10 only over a portion of its length.
[0097] As in Figure 2 As shown in FIG. 2 , the device 2 has a device 20 for photographic imaging. The device 20 is used to generate photographs of the heat exchanger 12 and transmit them to a control unit 22 of the device 2. The control unit 22 can have a computer for evaluating the photographs, be connected to a computer for evaluating the photographs and / or be connected to a server for evaluating the photographs.
[0098] The control unit 22 is designed to detect the icing state of the heat exchanger 12 and to determine the defrosting time by evaluating the first image.
[0099] Furthermore, the control unit 22 is designed to control the defrosting process performed by means of the heating device 16 by means of an evaluation of the second photograph, wherein the evaluation of the first photograph is different from the evaluation of the second photograph. The control unit 22 may also be referred to as control device 22 .
[0100] Both the first and the second photographic image are generated by means of the device 20 for photographic imaging and are transmitted to the control unit 22 .
[0101] The device 20 for photographic imaging is a camera 20 which is designed both for photographic imaging in the visible wavelength range and for photographic imaging in the invisible wavelength range and for this purpose has a sensor 24 for corresponding imaging in these wavelength ranges.
[0102] The device 2 also has a temperature sensor 26 , a pressure sensor 28 and a humidity sensor 30 , which transmit signals to the control unit 22 .
[0103] The device 2 is designed to carry out the method according to the invention which is described below.
[0104] according to Figure 6 The flow chart 32 relates to the operation of the heat exchanger 12 of the device 2 .
[0105] Block 34 of flow chart 32 illustrates the sensor plane of the method and represents the signals of sensors 26, 28 and 30 and the provision of a first photograph of heat exchanger 12 and / or the provision of a second photograph of heat exchanger 12. Block 34 thus forms input data for the method according to the invention, which are transmitted to a database 36.
[0106] These data are subsequently processed or processed in a further method step represented by block 38 .
[0107] According to step 40, it is checked whether the heating device 16 is switched on or whether a defrost process is currently active. If the heating device 16 is not switched on and therefore no defrost process is active, branch 42 is implemented, which relates to the detection of the icing state of the heat exchanger 12 and the determination of the defrost time of the heat exchanger 12. If the heating device 16 is switched on and therefore a defrost process is active, branch 44 is implemented, which relates to the control of the defrost process.
[0108] First, the method steps of branch 42 are described.
[0109] In method step 46, the first photograph of the heat exchanger 12 is evaluated. The evaluation is performed with the aid of KI-based image evaluation software.
[0110] The first photograph is a photograph of the heat exchanger 12 in the visible wavelength range. The photograph has been produced by means of a device 20 for photographic imaging.
[0111] The KI model on which method step 46 is based is generated with the aid of training data, which are represented by block 48. In particular, block 48 represents a machine learning, i.e. a statistical model based on reference images that were manually evaluated and classified by a specialist. The KI model is therefore based on reference images of photographs in the visible wavelength range, which are exemplarily Figure 5 Shown in.
[0112] Here, a first set 50 of photographs in the visible wavelength range shows, with reference to image 52, an icing state requiring defrosting of heat exchanger 12. Furthermore, a second set 54 of photographs in the visible wavelength range shows, with reference to image 52, an icing state not requiring defrosting of heat exchanger 12.
[0113] Reference image 52 of the photograph of heat exchanger 12 in the visible wavelength range has been divided into ten classes according to the degree of icing discernible in reference image 52 , which are now numbered successively IX, the degree of icing increasing with rising numbers.
[0114] Reference images 52 with degrees of icing I, II, III, IV and V are assigned to second group 54 , while reference images with degrees of icing VI, VII, VIII, IX, X are assigned to first group 50 .
[0115] The photograph 56 of the heat exchanger 12 in the visible wavelength range, which is created by means of the device 20 for photographic imaging, is as follows: Figure 6In method step 58 , an assignment to class IX is performed using the KI model 46 , and in method step 60 , it is determined using the assigned class using the associated groups 50 , 54 whether defrosting is necessary or not.
[0116] As long as defrosting is not required, the branch 42 is restarted as a loop corresponding to the path 64 starting from the branch 62 .
[0117] If defrosting is required, a defrosting time is determined in order to initiate defrosting, corresponding to block or process step 66. Branch 44 of flowchart 32 is therefore passed with the start of the defrosting process, since query or condition 40 now leads to branch 44 based on switched-on heating device 16.
[0118] The defrosting of the heat exchanger 12 is controlled by evaluating the second photograph 68. The second photograph 68 is produced by means of the device 20 for photographic imaging and is a photograph of the heat exchanger 12 in the invisible wavelength range.
[0119] The evaluation of the second photograph 68 is likewise based on a KI model 70 which has been generated based on training data during machine learning according to method step 72. In particular, block 72 represents machine learning, ie a statistical model based on reference images that were manually evaluated and classified by a specialist.
[0120] Using method steps 74 and 76 , an assignment of the photographs 68 in the invisible wavelength range to a class can be carried out in a manner similar to the above description regarding the photographs in the visible wavelength range in order to stop the defrosting process as a function of the icing state of the heat exchanger 12 .
[0121] If the assignment of the photographs 68 in the invisible wavelength range to the class indicates that further defrosting is required, branch 44 corresponding to path 80 is repeated. If the assignment of the photographs 68 in the invisible wavelength range to the class indicates that further defrosting is not required, path 82 leads to process step 84 which causes the heating device 16 to be switched off.
[0122] Due to the switched-off heating device 16 , branch 42 is now again routed through the circuit for such a long time that a necessary defrosting of heat exchanger 12 is detected.
[0123] The signals of the sensors 26 , 28 , 30 can be used for plausibility testing of the image evaluation both during the detection of icing conditions and during the control of the defrosting process.
[0124] Provision can be made for a first time interval between providing and evaluating two consecutive photographs in the visible wavelength range to be greater than a second time interval between providing and evaluating two consecutive photographs in the invisible wavelength range.
[0125] It can be provided that the device for photographic imaging 20 is arranged in the housing 4 according to an alternative design. In particular, it can be provided that the device for photographic imaging 20 is arranged between the blower 8 and the heat exchanger 12 in the housing 4.
[0126] It can be provided that the heat exchanger according to an alternative design is a so-called microchannel heat exchanger which has, for example, parallel channels for conducting the cooling medium and lamellae arranged therebetween.
[0127] Reference numerals list
[0128] 2 Equipment / Cooling System
[0129] 4 Shell
[0130] 6 Guardrail
[0131] 8 Blower
[0132] 10 sheets / cooling sheets 10
[0133] 12 Heat transfer
[0134] 14 Pipeline
[0135] 16 Heating device
[0136] 18 Heating rod
[0137] U Environment
[0138] L Longitudinal direction
[0139] 20 Devices for photographic imaging
[0140] 22 Control Unit
[0141] 24 Sensors
[0142] 26 Temperature Sensor
[0143] 28 Pressure Sensor
[0144] 30 Humidity Sensor
[0145] 32 Flowchart
[0146] 34 blocks / input data / input signal
[0147] 36 Database
[0148] 38 blocks / processing
[0149] 40 Conditions / Branches
[0150] 42 branch "Detection of icing conditions"
[0151] 44 branch "Controlled defrost"
[0152] 46KI Model / Evaluation
[0153] 48 Training Data / Machine Learning
[0154] 50 First set of reference images
[0155] 52 Reference Images
[0156] 54 The second set of reference images
[0157] 56 Photos in the visible wavelength range
[0158] 58 Methods and Steps
[0159] 60 Methods and Steps
[0160] 62 Conditions / Branches
[0161] 64 Path
[0162] 66 Process Steps
[0163] 68 Photos in the invisible wavelength range
[0164] 70KI model
[0165] 72 Training Data / Machine Learning
[0166] 74 Methods and Steps
[0167] 76 Methods and Steps
[0168] 78 Conditions / Branches
[0169] 80 Path
[0170] 82 Path
[0171] 84 Methods and Steps
Claims
1. The method comprises the following steps: operating a heat transfer device (12); detecting an icing state of the heat exchanger (12) and determining a defrosting time of the heat exchanger (12) by evaluating a first photograph (56) of the heat exchanger (12); starting a defrosting process of the heat exchanger (12) by means of a heating device (16) at the defrosting time and controlling the defrosting process by means of an evaluation of a second photograph (68) of the heat exchanger; in, The evaluation of the first photograph (56) is different from the evaluation of the second photograph (68).
2. The method according to claim 1, characterized in that The first photograph (56) is a photograph in the visible wavelength range.
3. The method according to claim 2, characterized in that An evaluation of the first photograph (56) is performed with the aid of image evaluation software, wherein two or more reference images (52) of the photographs (52) in the visible wavelength range are provided to the image evaluation software and a comparison of the reference images (52) with the corresponding first photographs (56) is performed with the aid of the image evaluation software.
4. The method according to claim 3, characterized in that The image evaluation software is based on KI.
5. The method according to claim 3 or 4, characterized in that The first set (50) of reference images (52) of the photographs (52) in the visible wavelength range show an icy state of the heat exchanger (12) requiring defrosting, and The second set (54) of reference images (52) of the photographs (52) in the visible wavelength range show an icy state of the heat exchanger (12) that does not require defrosting, In this case, the defrost time is defined as long as one or more of the first photographs (56) of the image evaluation software are assigned to the first group (50) of photographs in the visible wavelength range.
6. The method according to any one of claims 3 to 5, It is characterized in that The reference image (52) of the photograph (52) in the visible wavelength range is divided into two or more categories (IX) according to the degree of icing to be identified in the reference image (52).
7. The method according to claim 5 and claim 6, It is characterized in that Assigning the reference image (52) to the first group (50) or to the second group (54) using its respective class (IX), wherein one or more classes (VI-X) belong to a first group (50), wherein one or more classes (IV) belong to the second group (54), In this case, a class (I-X) assigned to the first group (50) is not assigned to the second group (54), and vice versa.
8. The method according to any one of the preceding claims, characterized in that The second photograph (68) is a photograph in the invisible wavelength range.
9. The method according to claim 8, characterized in that An evaluation of the second photograph (68) is carried out with the aid of image evaluation software, wherein two or more reference images of the photograph in the invisible wavelength range are provided to the image evaluation software and a comparison of the reference images with the corresponding second photograph (68) is carried out with the aid of the image evaluation software.
10. The method according to claim 9, characterized in that The image evaluation software is based on KI.
11. The method according to claim 9 or 10, characterized in that The first group of reference images of the photographs in the invisible wavelength range show an icing state of the heat transfer device that requires defrosting, and the second group of reference images of the photographs in the invisible wavelength range show an icing state of the heat transfer device that does not require defrosting, wherein the defrosting process is terminated as long as one or more of the second photographs (68) of the image evaluation software belong to the second group of reference images of the photographs in the invisible wavelength range.
12. The method according to any one of claims 9 to 11, characterized in that The reference image of the photograph in the invisible wavelength range is divided into two or more categories according to the degree of ice formation to be identified on the reference image.
13. The method according to claim 11 and claim 12, characterized in that The reference images are assigned to the first group or the second group using their respective classes, wherein one or more classes are assigned to the first group, wherein one or more classes are assigned to the second group, wherein classes assigned to the first group are not assigned to the second group, and vice versa.
14. The method according to any one of claims 8 to 13, characterized in that: The evaluation of the second photograph is a thermal image evaluation of the intensity of the reflection in the invisible wavelength range, wherein the second photograph is a thermal image.
15. The method according to any one of the preceding claims, characterized in that The second photograph of the assessment is provided in grayscale.
16. The method according to any one of the preceding claims, characterized in that A first time interval between providing and evaluating two consecutive photographs in the first photograph is greater than a second time interval between providing and evaluating two consecutive photographs in the second photograph.
17. The method according to any one of the preceding claims, characterized in that In order to determine the icing state and / or the defrosting time and / or to control the defrosting process, sensor data of one or more of the following sensors are used: temperature sensor (26), pressure sensor (28), humidity sensor (30).
18. The method according to any one of the preceding claims, characterized in that The evaluation of the first photograph (56) and / or the evaluation of the second photograph (68) is performed at least partially with the help of a server, wherein the control device (22) of the heating device is connected to the server via a cable connection or a wireless data connection, and / or the evaluation of the first photograph and / or the evaluation of the second photograph is performed at least partially with the help of a computer assigned to the heat exchanger and the heating device, wherein the control device (22) of the heating device is connected to the computer via a cable connection or a wireless data connection.
19. The method according to any one of the preceding claims, characterized in that A service notification and / or an alarm notification is generated and outputted based on the evaluation of the first photograph (56) and / or based on the evaluation of the second photograph (68); and / or the number of devices for photographic imaging, in particular cameras, for detecting the second photograph (68) is greater than the number of cameras for detecting the first photograph (56); and / or exactly one device for photographic imaging, in particular camera, is provided for detecting the first photograph (56); and / or providing two or more devices for photographic imaging, in particular cameras, for detecting the second photograph (68); And / or a plurality of devices for photographic imaging, in particular cameras, are provided for detecting the second photographic image (68), the devices being arranged distributed along the longitudinal extension of the heat exchanger (12).
20. Equipment, comprising a heat transfer device (12), - wherein the heat exchanger (12) has a pipe (14) which conducts a cooling medium, -in, The pipe (14) is connected to a plurality of cooling fins (10) of the heat exchanger (12). comprising a blower (8) for conveying an air volume flow, comprising a heating device (16) for defrosting the heat exchanger (12), comprising a device (20) for photographic imaging and comprising a control unit (22), wherein the control unit (22) is designed to detect the icing state of the heat exchanger (12) and to determine the defrosting time by evaluating the first photograph (56), wherein the control unit (22) is designed to control a defrosting process carried out by means of the heating device (16) by means of an evaluation of the second photograph (68) and - wherein the evaluation of the first photograph (56) is different from the evaluation of the second photograph (68).
21. The device according to claim 20, characterized in that The first photograph (56) is a photograph in the visible wavelength range.
22. Apparatus according to claim 20 or claim 21, characterised in that The second photograph (68) is a photograph in the invisible wavelength range.
23. The device according to any one of claims 20 to 22, characterized in that The device (20) for photographic imaging has a first camera including a sensor for photographic imaging in the visible wavelength range and a second camera including a sensor for photographic imaging in the invisible wavelength range, and / or The device (20) for photographic imaging has a camera for photographic imaging both in the visible wavelength range and in the invisible wavelength range, and / or The device (20) for photographic imaging has a thermal imaging camera, and / or The device (20) for photographic imaging has an infrared camera.
24. The device according to any one of claims 20 to 23, characterized in that One or more sensors selected from the following sensors are provided: a temperature sensor (26), a pressure sensor (28), a humidity sensor (30); and / or The number of devices for photographic imaging, in particular cameras, for detecting the second photograph (68) is greater than the number of cameras for detecting the first photograph (56); and / or providing exactly one device for photographic imaging, in particular a camera, for detecting a first photographic picture (56); and / or Two or more devices for photographic imaging, in particular cameras, are provided for detecting a second photograph (68); and / or A plurality of devices for photographic imaging, in particular cameras, are provided for capturing second photographic images (68), the devices being arranged distributed along the longitudinal extension of the heat exchanger (12).
25. The device according to any one of claims 20 to 24, characterized in that The device (2) is designed to carry out a method according to one of claims 1 to 19.