Method for operating a cooling device in the event of a leak, and a corresponding cooling device

Abstract

The invention relates to a method for operating a cooling device (1) for switch cabinet air conditioning or the air conditioning of an IT environment, more particularly a data centre, said method having the following steps: A. operating a refrigeration machine of the cooling device (i), the refrigeration machine comprising a refrigerant circuit with a compressor (2), a condenser (3), an expansion organ (4) and an evaporator (5); B. detecting a leak in the refrigerant circuit where refrigerant escapes from the refrigerant circuit; characterised by C. blocking a feed (6) of the evaporator (5) between the evaporator (5) and the condenser (3); and D. activating the compressor (2) or keeping same activated. A corresponding cooling device is also described.

Description

[0001] Procedure for operating a cooling device in the event of a leak and a corresponding cooling device

[0002] The invention is based on a method for operating a cooling device for control cabinet air conditioning or for air conditioning an IT environment, for example, a data center. The method comprises operating a refrigeration machine of the cooling device. The refrigeration machine has a refrigerant circuit with a compressor, a condenser, an expansion device, and an evaporator. The method further comprises detecting a leak in the refrigerant circuit, wherein refrigerant escapes from the refrigerant circuit. Such a method and a corresponding cooling device are known from DE 102018109604 Ai.

[0003] Directive 2006 / 42 / EC (Machinery Directive) requires that gases used in machinery do not pose a risk of explosion or fire, although it is assumed that individual components will fail. Therefore, if a component containing a refrigerant in an enclosure cooling unit has a suspected leak, it can be assumed that flammable gas (refrigerant) will enter the enclosure and ignite on components that ignite arcs during operation. Without a safety function that reliably prevents this, enclosure cooling units that use flammable refrigerants cannot comply with the Machinery Directive or operate with the required safety for the end user.

[0004] The cooling devices known from the state of the art for control cabinet air conditioning have the disadvantage that they are comparatively complex to implement, since, for example, various actively driven closing elements are required to fluidically separate the air circuit of the cooling device from the control cabinet atmosphere in the interior of the control cabinet housing in the event of a detected leak or if a flammable refrigerant enters the interior of the control cabinet.

[0005] The object of the invention is therefore to propose a method for operating a cooling device in the event of a leak, as well as a corresponding cooling device, which can be implemented using simple technical means and are therefore inexpensive to provide. This object is achieved by a method having the features of claim 1. The subordinate claim 10 relates to a corresponding cooling device. The dependent claims each relate to advantageous embodiments of the invention.

[0006] Accordingly, the method involves shutting off a flow line of the evaporator between the evaporator and the condenser, and activating and / or keeping the compressor activated. The invention is based on the finding that the evaporator is particularly susceptible to leakage in the internal air circuit of the cooling device, i.e., in the area of ​​the cooling device that is open to the atmosphere of the control cabinet or the atmosphere of the IT environment, for example, a data center.

[0007] If the evaporator or a piping system of the evaporator that is connected to the refrigerant circuit is brought to a negative pressure compared to the atmosphere in the interior of the control cabinet housing or the IT environment, or if the internal pressure in the piping system is further adjusted to the atmospheric pressure, the uncontrolled leakage of refrigerant, which could lead to critical enrichment of the refrigerant, can be particularly effectively prevented.

[0008] The evaporator can, for example, be designed as an air-liquid heat exchanger. The air-liquid heat exchanger can have a finned pack through which the air flowing through the evaporator flows. The finned pack can be penetrated by a piping system connected to the refrigerant circuit in order to achieve heat exchange between the air flowing through the evaporator and the refrigerant flowing through the piping system. For example, the piping system passing through the evaporator, in particular the finned pack, can have a plurality of straight and parallel pipe sections that are connected to one another at opposite end faces of the evaporator via pipe bends, in particular 180° pipe bends. The connection points can, in particular, be designed as joints, for example as soldered joints, which are susceptible to leakage.The pipe bends themselves are also more susceptible to leaks than the straight pipe section. The method according to the invention can therefore be configured to drain the refrigerant, particularly from the evaporator and preferably also from the remaining components of the refrigerant circuit arranged in the internal air circuit, in the event of a leak.

[0009] It can therefore be provided that the activation and / or keeping activated of the compressor comprises the emptying of the refrigerant circuit at least in a line section of the refrigerant circuit which is arranged in an internal air circuit of the cooling device.

[0010] Refrigerant emptied from the line section of the refrigerant circuit arranged in the inner air circuit can be transferred to a line section of the refrigerant circuit arranged in the outer air circuit.

[0011] The transfer of the refrigerant into a line section arranged in the external air circuit can comprise the introduction of the refrigerant into a buffer storage, preferably into an air-liquid heat exchanger of the condenser, particularly preferably into a line system of the air-liquid heat exchanger, with which the refrigerant is passed through the air-liquid heat exchanger in thermal contact with a plurality of fins of the air-liquid heat exchanger.

[0012] To shut off the evaporator's flow line, the expansion device can be moved into a closed position that is completely or essentially impermeable to the refrigerant. Accordingly, no additional shut-off device is required, so the process can be carried out with conventional refrigeration devices without any structural modifications.

[0013] Activating and / or maintaining the compressor activated may include increasing the speed of the compressor, wherein the compressor is preferably operated at a maximum speed.

[0014] Shutting off the evaporator flow between the evaporator and the condenser may involve shutting off a section of the refrigerant circuit located in an external air circuit of the refrigeration device. When activating and / or maintaining the compressor activated, the compressor may be kept activated either for a predetermined minimum period and / or until a section of the refrigerant circuit located in the internal air circuit of the refrigeration device, including the evaporator, is completely or substantially completely emptied of refrigerant.

[0015] After activating and / or maintaining the activated compressor, the method may include shutting off a suction line of the compressor, via which the compressor is connected to a return line of the evaporator, and, if necessary, deactivating the compressor. Deactivation preferably occurs after shutting off the suction line.

[0016] According to another aspect, a cooling device for the air conditioning of switch cabinets or the air conditioning of an IT environment, in particular a data center, is described. The cooling device accordingly comprises a refrigeration machine with a refrigerant circuit, wherein the refrigerant circuit has a compressor, a condenser, an expansion device, and an evaporator. A supply line of the evaporator has a shut-off device between the evaporator and the condenser, which is designed to completely close the supply line in the event of a leak in the refrigerant circuit. The cooling device is not limited to any specific designs and can, for example, be a compact cooling device for suspended installation on a switch cabinet housing, a slide-in cooling device for integration into a switch cabinet row, a split unit, or the like.

[0017] The shut-off device can be the expansion device of the refrigerant circuit. Therefore, an additional shut-off device would not be necessary to implement the method according to the invention.

[0018] The shut-off device can be motor-driven. It can be controlled by a control unit that has a signal input for a refrigerant sensor. The refrigerant sensor can be arranged in or on the cooling unit or positioned independently of the cooling unit. For example, the refrigerant sensor can be arranged on an outside of the cooling unit facing the interior of a control cabinet or an IT environment, for example in a data center. The refrigerant sensor can be arranged, for example, in an air inlet opening or an air outlet opening of an internal air circuit of the cooling unit or in the internal air circuit of the cooling unit. The refrigerant sensor can be connected wirelessly or wired to the signal input of the control unit for signal transmission.

[0019] The cooling device can have a further, preferably motor-driven shut-off device in a suction line of the compressor. The further shut-off device can serve, after at least the evaporator or a section of the refrigerant circuit located in the inner air circuit has been emptied, to fluidically separate the section of the refrigerant circuit located in the inner air circuit, with its integrated components, for example, the evaporator, from the part of the refrigerant circuit located in the outer air circuit. The refrigerant is stored in the part of the refrigerant circuit located in the outer air circuit.

[0020] At least the condenser, the compressor, and at least one fan for supplying air to the condenser can be housed separately from the evaporator in a separate housing, which is connected to the evaporator's supply and return lines via two pipe runs. The cooling unit can be designed as a so-called split unit with separate housings connected to each other via the two pipe runs.

[0021] The pipe section connected to the evaporator's supply line can include the shut-off device. The shut-off device can preferably be located closer to the evaporator than to the condenser along the pipe section. This ensures that, in the event of a leak, the pipe sections can be used as a buffer storage for the refrigerant discharged from the evaporator.

[0022] The pipe section connecting the evaporator return line and the compressor suction line can have an additional shut-off device. This additional shut-off device can be located closer to the evaporator than to the compressor along the pipe section. Here, too, the pipe section can serve as a buffer storage for refrigerant in the event of a leak.

[0023] The compressor, the condenser, the expansion device, the evaporator, and the at least one shut-off device can be connected to one another via a piping system of the refrigerant circuit. The piping system can be conditioned with respect to its volume, in particular at least one of the piping cross-section and the piping length, such that in the event of a leak, when the evaporator supply line is shut off, the piping system acts as a buffer storage for the refrigerant compressed by the compressor.

[0024] The compressor can be arranged in the inner air circuit, preferably in a housing in which at least the evaporator and the compressor are arranged. The housing can preferably be designed independently of another housing in which the condenser and the outer air circuit are arranged. The housing can be arranged with the inner air circuit in an IT environment, such as a data center, and the other housing with the outer air circuit can be arranged outside the IT environment.

[0025] Further details of the invention are explained with reference to the following figures.

[0026] Figure i shows an exemplary embodiment of a switch cabinet arrangement with a cooling device according to the invention; and

[0027] Figure 2 shows an exemplary embodiment of an IT environment with a further embodiment of a cooling device according to the invention.

[0028] The embodiment according to Figure 1 essentially consists of a switch cabinet housing 100, on which a cooling device 1 is mounted, for example in a suspended manner. The cooling device 1 has, on a vertical side wall in an upper region, an air inlet in the internal air circuit 7 for warm air and, in a lower region, an air outlet from the internal air circuit 7 for cooled air. Heat-emitting components (not shown) can be arranged in the interior 101 of the switch cabinet 100, which components are acted upon by air cooled by the cooling device 100. The components in the interior 101 can generate arcs during operation, at which arcs could ignite a refrigerant escaping from the cooling device 1 in the event of a leak and forming a stoichiometric mixture with the air in the interior 101 in the atmosphere of the interior 101.The cooling device 1 accordingly has an inner air circuit 7, through which the air taken in from the switch cabinet interior 101 is passed, passing through an evaporator 5, whereby the air cools. Fluidically separated from the inner air circuit 7 is an outer air circuit 8, through which ambient air is passed. In a lower region of the outer air circuit 8, ambient air is introduced into the outer air circuit 8. The ambient air acts on the condenser 3 and leaves the outer air circuit 8 as heated air in an upper region of the cooling device 1. A compressor 3 and an expansion element 4 are also arranged in the outer air circuit 8.

[0029] In the embodiment shown in Figure 1, the expansion element 4 further functions as a shut-off element 11. The function of a shut-off element 11 is necessary for carrying out the method according to the invention. Accordingly, if a leak in the refrigerant circuit is detected, the cooling device can be operated such that the refrigerant contained in the refrigerant circuit is concentrated in the region of the refrigerant circuit located in the outer air circuit 8, and in particular, the evaporator located in the inner air circuit and particularly susceptible to leakage is emptied or substantially emptied.

[0030] To detect the leak, a refrigerant sensor can be arranged in the internal air circuit 7 or in the interior space 101. According to the method according to the invention, in the event of a leak, the flow line 6 of the evaporator 5 between the evaporator 5 and the condenser 3 is shut off. Furthermore, the compressor 2 is activated if it is not already in an active state. If the compressor 2 is already in an active state, it is maintained in the active state in order to achieve the most complete emptying possible of the evaporator 5 and the remaining pipe sections of the refrigerant circuit arranged in the internal air circuit 7.

[0031] In contrast to the embodiment shown in Figure 1, in the embodiment shown in Figure 2 the cooling device 1 is designed as a split device in which at least the condenser 3 and the evaporator 2 with the external air circuit 8 are arranged in a housing 13 separate from the other components of the cooling device 1. The housing 13 is connected via two pipe sections to the flow 6 and the return 10 of the evaporator 5. The embodiment shown in Figure 2 is therefore particularly suitable for air conditioning an IT environment, for example a data center, in which the housing 13 with the condenser 3 can be arranged outside the IT environment or the data center, for example on the roof of a container or a building.

[0032] Furthermore, the embodiment according to Figure 2 has a further shut-off device 12 in the return line 10 of the evaporator 5. This can serve to separate the components located in the internal air circuit 7 from the rest of the refrigerant circuit after the evaporator 5 or the components of the refrigerant circuit located in the internal air circuit 7 have been emptied, after which the compressor 2 could also be deactivated without risking refrigerant flowing back into the part of the refrigerant circuit located in the internal air circuit. The further shut-off device 12 can also be implemented in the embodiment shown in Figure 1.

[0033] The evaporator is configured in a housing 15 with an air inlet and an air outlet. The internal air circuit is guided through the evaporator 5 in the housing 15. In addition to the evaporator 5, the two shut-off devices 11, 12 are also accommodated in the housing 15. In an upper region of the housing 15, warm air from the interior 1001 of the IT environment 1000, for example, from a data center, is drawn into the internal air circuit 7, passed through the evaporator 5, and, in a lower region of the housing 15, is fed from the internal air circuit 7 or the housing 15 back into the interior 1001.

[0034] In contrast to the embodiment shown in Figure 2, in the embodiment shown in Figure 3, the compressor 2 is arranged in the internal air circuit. Analogous to the embodiment shown in Figure 2, the housing 13 for the condenser 3 can be an outdoor housing, which is arranged, for example, outside a data center, for example, on the roof of a data center. A collector 14 is also arranged in the housing 13 of the condenser 3 to provide a receptacle for refrigerant in the event of a leak and when the flow line 6 of the evaporator 5 is blocked off by the shut-off device 4.

[0035] The features of the invention disclosed in the above description, in the drawings, and in the claims may be essential for the realization of the invention, both individually and in any combination. List of reference symbols

[0036] 1 cooling device

[0037] 2 compressors

[0038] 3 condensers

[0039] 4 Expansion organ

[0040] 5 evaporators

[0041] 6 Lead-up

[0042] 7 Inner air circuit

[0043] 8 outer air circuit

[0044] 9 Suction line io Return ii Shut-off device

[0045] 12 additional shut-off device

[0046] 13 Condenser housing

[0047] 14 collectors

[0048] 15 Evaporator housing

[0049] 100 control cabinet housings

[0050] 101 Interior

[0051] 1000 IT environment / data center

[0052] 1001 Interior of the IT environment or data center

Claims

Patent claims: Method for operating a cooling device (i) for the air conditioning of a switch cabinet or the air conditioning of an IT environment, for example a data center, comprising the steps: A. Operating a refrigeration machine of the refrigeration device (i), the refrigeration machine comprising a refrigerant circuit with a compressor (2), a condenser (3), an expansion device (4) and an evaporator (5); B. Detecting a refrigerant circuit leakage where refrigerant escapes from the refrigerant circuit; characterized by C. Shutting off a flow line (6) of the evaporator (5) between the evaporator (5) and the condenser (3); and D. Activating and / or maintaining the activated compressor (2). Method according to claim 1, wherein activating and / or maintaining the activated compressor (2) comprises emptying the refrigerant circuit in a line section of the refrigerant circuit that is arranged in an internal air circuit (7) of the refrigeration device (1). Method according to claim 1 or 2, wherein refrigerant emptied from the line section of the refrigerant circuit arranged in the internal air circuit (7) is transferred to a line section of the refrigerant circuit arranged in the external air circuit (8).Method according to claim 3, wherein the transfer of the refrigerant into a line section arranged in the external air circuit (8) comprises introducing the refrigerant into a buffer storage, preferably into an air-liquid heat exchanger of the condenser (3), particularly preferably into a line system of the air-liquid heat exchanger, with which the refrigerant is passed through the air-liquid heat exchanger in thermal contact with a plurality of fins of the air-liquid heat exchanger. - Method according to one of the preceding claims, in which, in order to shut off the flow line (6) of the evaporator (5), the expansion element (4) is transferred into a closed position that is completely impermeable or essentially impermeable to the refrigerant. . Method according to one of the preceding claims, in which activating and / or keeping the compressor (2) activated comprises increasing the speed of the compressor (2), wherein the compressor (2) is preferably operated at a maximum speed. . Method according to one of the preceding claims, in which shutting off the flow line (6) of the evaporator (5) between the evaporator (5) and the condenser (3) comprises shutting off a line section of the refrigerant circuit that is arranged in an external air circuit (8) of the refrigeration device (1). .Method according to one of the preceding claims, wherein, during the activation and / or keeping activated of the compressor (2), the compressor (2) is kept activated either for a predetermined minimum period and / or until a section of the refrigerant circuit arranged in the internal air circuit (7) of the cooling device (1), including the evaporator (5), is completely or essentially completely emptied of the refrigerant. Method according to one of the preceding claims, which, after the activation and / or keeping activated of the compressor (2), comprises shutting off a suction line (9) of the compressor (2), via which the compressor (2) is connected to a return line (10) of the evaporator (5), and optionally deactivating the compressor (2).Cooling device (1) for control cabinet air conditioning, in particular for carrying out the method according to one of the preceding claims, in which the cooling device (1) has a refrigeration machine with a refrigerant circuit, wherein the refrigerant circuit has a compressor (2), a condenser (3), an expansion element (4) and an evaporator (5), characterized in that a supply line (6) of the evaporator (5) between the evaporator (5) and the condenser (3) has a shut-off element (11) which is designed to completely close the supply line (6) in the event of a leak in the refrigerant circuit. Cooling device (i) according to claim 10, wherein the shut-off element (n) is the expansion element (4). Cooling device (1) according to claim 10 or 11, wherein the shut-off element (11) is motor-driven and controlled by a regulating and control unit having a signal input for a refrigerant sensor. Cooling device (1) according to claim 12, wherein the refrigerant sensor is arranged in or on the cooling device (1), for example on an outer side of the cooling device (1) facing a control cabinet interior, in an air inlet opening or an air outlet opening of an internal air circuit (7) of the cooling device (1), or in the internal air circuit (7) of the cooling device (1), wherein the refrigerant sensor is connected wirelessly or by wire to the signal input of the regulating and control unit. Cooling device (1) according to one of claims 10 to 13, which has a further, preferably motor-driven shut-off device (12) in a suction line (9) of the compressor (2).Cooling device (1) according to one of claims 10 to 14, in which at least the condenser (3), the compressor, and at least one fan for supplying the condenser (3) with air are housed separately from the evaporator in a separate housing (13) which is connected to the flow and return lines (10) of the evaporator (5) via two pipe sections. Cooling device (1) according to claim 15, in which the pipe section connected to the flow of the evaporator (5) has the shut-off element (11), wherein the shut-off element (11) is preferably arranged closer to the evaporator than to the condenser along the pipe section. Cooling device (1) according to claim 15 or 16, wherein the pipe section connected to the return line (10) of the evaporator (5) and the suction line (9) of the compressor (2) has a further shut-off element (12), wherein the further shut-off element is preferably arranged along the pipe section closer to the evaporator (5).Cooling device (1) according to one of claims 10 to 17, in which the compressor (2), the condenser (3), the expansion element (4), the evaporator (5) and the at least one shut-off element (11, 12) are connected via a piping system of the. refrigerant circuit are connected to one another, wherein the piping system is conditioned with regard to its volume, in particular at least one of the piping cross-section and the piping length, such that in the event of a leak, when the supply line (6) of the evaporator (5) is shut off, the piping system acts as a buffer storage for refrigerant compressed by the compressor. The refrigeration device (1) according to any one of claims 10 to 18, wherein the compressor (2) is arranged in the inner air circuit (7), in a housing (15) in which at least the evaporator (5) and the compressor (2) are arranged, wherein the housing (15) is preferably designed independently of a further housing (13) in which the condenser (3) and the outer air circuit (8) are arranged, and wherein the housing (15) with the inner air circuit (7) is arranged in an IT environment (1000) and the further housing (13) with the outer air circuit (8) is arranged outside the IT environment (1000).

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