Cooling device for a control cabinet having a gas-tight enclosure enclosing a cooling circuit

Abstract

The invention relates to a cooling device (1) for a switch cabinet, comprising an internal air circuit (4), an external air circuit (5), a cooling circuit (6) carrying a flammable refrigerant, and a housing (3), wherein the cooling circuit (6) comprises at least one evaporator (9), a condenser (10), a compressor (7), and an expansion valve (8), wherein the evaporator (9) is arranged in the internal air circuit (4) and the condenser (10) is arranged in the external air circuit (5), characterized in that the housing (3) is designed to enclose the cooling circuit (6) in a gas-tight manner with respect to the internal air circuit (4) and the external air circuit (5), such that the evaporator (9) and the condenser (10), as well as corresponding pipes (14), are arranged outside the housing (3) as the only components of the cooling circuit (6), characterized in thatthat the housing (3) has a connection (15) to an environment (16) of the switch cabinet or to the outside air circuit (5), and wherein the connection (15) has a filter (11) which is designed to adsorb a combustible gas, in particular the combustible refrigerant.

Description

[0001] The invention relates to a cooling device for a switch cabinet, comprising a housing, wherein the housing is designed to enclose a cooling circuit in a gas-tight manner with respect to an internal air circuit and an external air circuit, such that an evaporator and a condenser as well as corresponding pipes are arranged outside the housing as the only components of the cooling circuit.

[0002] Current cooling devices for control cabinets use fluorinated gases (F-gases) as refrigerants. While these do not damage the ozone layer, the F-Gas Regulation 2024 / 573 prohibits the use of F-gases as refrigerants in control cabinet cooling devices from 2032 onwards to reduce emissions. Based on current knowledge, carbon dioxide or flammable refrigerants, such as propane (R290), remain as alternatives. Due to its thermodynamic properties, propane is ideally suited for use in control cabinet cooling devices, but its flammability poses a safety risk. A leak in a cooling circuit of the cooling device can cause the flammable refrigerant to escape uncontrollably and be ignited by ignition sources in the surrounding area. However, potential ignition sources cannot be completely ruled out, particularly in industrial environments.However, according to the Machinery Directive 2006 / 42 / EC, gases used in a machine must not pose a risk of explosion or fire.

[0003] DE 10 2019 118 977 A1 therefore proposes a device for safely conducting a thermodynamic cycle using a flammable working fluid, which device has a sorption channel with an adsorber containing activated carbon. At least a portion of an escaping working fluid can be bound via the adsorber. However, all components of a working fluid circuit are arranged within a housing. Therefore, the proposed approach cannot be transferred to a cooling device for a control cabinet with an internal and external air circuit without considerable effort.

[0004] A similar approach is pursued in EP 3 693 683 A1, in which a heat pump system with a heat pump using a flammable refrigerant includes a sorption bed with an adsorbent to absorb escaping refrigerant. Here, too, all components of the refrigeration circuit are arranged in a single housing, so transferring the concept to a cooling device with an indoor and outdoor air circuit is not possible without considerable effort.

[0005] DE 10 2011 116 863 A1 describes a method and a device for securing a closed thermodynamic cycle which is operated with a process fluid which contains or consists of at least one environmentally hazardous, toxic and / or flammable substance, wherein in the event of a leak in the cycle an adsorbent is brought into contact with the process fluid and the at least one environmentally hazardous, toxic and / or flammable substance is selectively bound by the adsorbent.

[0006] Further cooling devices are known from DE 20 2005 021 077 U1, DE 10 2016 112 851 A1 and DE 10 2011 116 863 A1.

[0007] The object of the invention is therefore to provide a cooling device for a control cabinet with an internal air circuit and an external air circuit, so that no flammable concentration of the flammable refrigerant is present outside the cooling device. The risk of ignition or explosion of the refrigerant due to ignition sources in the vicinity of the cooling device can thus be avoided or at least reduced.

[0008] This object is achieved by an arrangement having the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] Accordingly, a cooling device for a control cabinet is provided with an internal air circuit, an external air circuit, a cooling circuit, and an enclosure, wherein the cooling circuit comprises at least one evaporator, a condenser, a compressor, and an expansion valve. The evaporator is arranged in the internal air circuit, and the condenser is arranged in the external air circuit. The enclosure is designed to enclose the cooling circuit in a gas-tight manner with respect to the internal air circuit and the external air circuit, such that the evaporator and the condenser, as well as corresponding piping, are the only components of the cooling circuit located outside the enclosure.

[0010] The invention thus ensures that refrigerant escaping from leaks in the cooling circuit remains within the enclosure. This prevents flammable refrigerant from entering the environment and being ignited by an ignition source. Within the enclosure, a lower ignition limit of the flammable refrigerant can be exceeded because there is no ignition source present. Alternatively, an inert atmosphere can be provided within the enclosure.

[0011] An internal air circuit is an air circuit used to regulate the temperature inside the enclosure. For example, air from the interior can be supplied to the evaporator of the refrigeration circuit, and after passing over the evaporator, the cooled air can be returned to the interior.

[0012] An outside air circuit is an air circuit that dissipates waste heat from the cooling circuit to the environment. For this purpose, air from the environment can be supplied to the condenser of the cooling circuit, and after flowing over the condenser, the warmed air is released back into the environment.

[0013] Propane (R290) is considered a flammable refrigerant in this context. However, other flammable refrigerants, especially those with a global warming potential (GWP) of less than 10, such as ethane (R170) or partially halogenated fluoroolefins (HFO), are also encompassed within the meaning of the invention.

[0014] The pipes of the cooling circuit that are required to fluidically connect the evaporator and the condenser with the rest of the cooling circuit are considered to be the corresponding pipes.

[0015] Preferably, the length of the pipes between the housing and the evaporator or condenser is designed to be as short as possible. By "as short as possible" we mean that the pipes directly connect the housing and the evaporator or condenser. This ensures that all critical leak points of the cooling circuit are located within the housing. Preferably, therefore, the distance between the housing and the evaporator or condenser can be designed to be as small as possible; in particular, no other components are arranged between the housing and the evaporator or condenser. Particularly preferably, the evaporator and / or condenser is arranged directly on the housing. This makes it possible to completely avoid the need for a pipe arranged outside the housing between the housing and the evaporator and / or condenser.

[0016] Furthermore, the corresponding pipes outside the enclosure can be designed without any bends. Preferably, they are straight. This can further reduce the likelihood of leaks, since bends are subject to greater wear.

[0017] In particular, the enclosure is designed so that all critical leak points of the cooling circuit are located within the enclosure. In particular, it can be provided that bends, connection points, and connections of the cooling circuit are located within the enclosure.

[0018] The enclosure has a connection to the environment of the control cabinet or to the outside air circuit. The connection includes a filter designed to adsorb a flammable gas. This prevents the flammable refrigerant from accumulating in the enclosure, thus preventing spontaneous ignition within the enclosure.

[0019] The adsorption of the gas in the filter also creates a pressure difference that promotes flow from the housing to the filter. This promotes the removal of the flammable refrigerant from the leak point to the filter.

[0020] The filter can be arranged in the connection, immediately in front of the connection, for example on an inside of the housing, and / or immediately behind the connection, for example on an outside of the housing.

[0021] Preferably, the filter can have an active surface at least in some areas. The active surface can be implemented, for example, by means of a coating with an adsorbent material. A suitable adsorbent material can, in particular, be or comprise a zeolite and / or a silica gel.

[0022] Furthermore, the filter can have at least one flow-carrying element. The flow-carrying element can increase the contact time between the gas flow and a surface of the filter, thereby increasing the adsorption capacity of the filter. For example, it can be provided that the pores of the filter do not run straight through the filter, but are curved, preferably serpentine. Furthermore, it can be provided that a pore diameter is variable, and the filter can be provided with an active coating, particularly in areas with a larger pore diameter.

[0023] The filter is preferably designed to be replaceable. This allows the filter to be changed at specified intervals, for example. Alternatively, the filter can be equipped with an indicator that indicates a flammable gas load. This allows the filter to be changed whenever the load exceeds a certain limit.

[0024] In particular, the filter can be replaceable without tools. The filter itself or a filter holder can be attached to a housing of the cooling device via a clip connection. Furthermore, the filter can be designed as a cartridge that can be inserted into a filter holder or directly into the connection.

[0025] Furthermore, the filter can be designed to be regenerable. This allows for reuse. The filter can be regenerated after removal and then reinserted. Regeneration of the filter can be achieved by treatment with heat, pressure, and / or steam.

[0026] Preferably, the indoor air circuit and the outdoor air circuit are separated from each other by an air circuit separator. This allows fluidic decoupling between the indoor air circuit and the outdoor air circuit. The air circuit separator, in particular, has thermal insulation. This allows unwanted heat transfer between the two air circuits to be avoided or at least reduced.

[0027] The internal air circuit can comprise an internal fan that is fluidically connected to an internal housing of the control cabinet and is designed to draw in heated air from the internal housing and supply it to the evaporator. This allows the internal housing to be temperature-controlled.

[0028] The outside air circuit can comprise an outside fan that is fluidically connected to the environment of the control cabinet and is designed to draw in air from the environment and supply it to the condenser. In particular, it can be provided that the outside fan draws in air from a cold aisle, so that the supplied air has a temperature favorable for condensing the refrigerant. For this purpose, the air is supplied to the outside air circuit and discharged on opposite sides, in particular the front and rear, of the control cabinet.

[0029] Furthermore, the cooling unit can be mounted on an interior wall of the control cabinet or in a control cabinet door. This results in a space-saving arrangement of the cooling unit within the control cabinet. In particular, the cooling unit can be mounted on a suspension or rail system, allowing installation or removal of the cooling unit by a single person and / or without the need for tools. Furthermore, the cooling unit can be designed as a plug-in unit, making it suitable for retrofitting, for example.

[0030] Preferably, a housing of the cooling device and the inner wall of the switch cabinet or the switch cabinet door have two openings aligned with one another, wherein the internal fan of the internal air circuit is designed to extract heated air from the interior of the switch cabinet via the first aligned opening and to feed it back into the interior of the switch cabinet via the second opening downstream of the evaporator.

[0031] This allows a fluidic connection to be established between the interior of the control cabinet and the internal air circuit. The openings can be covered and / or filtered. The covering can, for example, enable the openings to be sealed, while the filter can remove dust or other airborne particles from the air.

[0032] Further details of the invention are explained with reference to the following figures. Fig. 1 shows a schematic representation of a cooling device according to the invention with a housing; Fig. 2 an exemplary embodiment of a cooling device according to the invention with a housing having a connection to an environment; and Fig. 3 an exemplary embodiment of a cooling device according to the invention with a housing having a connection to an outside air circuit.

[0033] Fig. Figure 1 shows a cooling device 1 for a control cabinet with a cooling device housing 2. Arranged within the cooling device housing are an internal air circuit 4, an external air circuit 5, a cooling circuit 6, and an enclosure 3. The cooling circuit 6 comprises an evaporator 9, a condenser 10, a compressor 7, and an expansion valve 8. These components are connected to each other via pipes. A flammable refrigerant is conveyed in the pipes.

[0034] The evaporator 9 is arranged in the internal air circuit 4, so that the refrigerant transforms into a gaseous state when heated air flows over the evaporator. The refrigerant is then compressed in the compressor 7. The condenser 10 is arranged in the external air circuit 5, so that the refrigerant transforms into a liquid state when cool air flows over the condenser 10. The liquid refrigerant is then expanded in the expansion valve 8 and fed back to the evaporator 9.

[0035] The housing 3 is designed to enclose the cooling circuit 6 in a gas-tight manner with respect to the internal air circuit 4 and the external air circuit 5, such that the evaporator 9 and the condenser 10, as well as corresponding pipes 14, are the only components of the cooling circuit 6 located outside the housing 3. This allows the escape of flammable refrigerant into the environment 16 to be almost completely prevented, since all leak-prone points of the cooling circuit 6 are located within the housing 3.

[0036] Furthermore, the housing 3 has a connection 15 to an environment 16 of the control cabinet. A filter 11 is arranged on the inside of the housing 3, in front of the connection 15. The filter 11 has an active surface for adsorbing the flammable refrigerant, which is coated with an adsorbent material. The adsorption on the active surface creates a pressure difference that causes a gas inlet stream 12 into the filter 11 due to overpressure. The flammable refrigerant is adsorbed in the filter 11, so that a gas stream 13 containing only small amounts of flammable refrigerant is released into the environment 16 via the connection 15. Although small amounts of flammable refrigerant can pass through the filter 11, the filter 11 is designed such that a lower ignition limit of the flammable refrigerant in the environment is not exceeded.This prevents ignition or explosion, even caused by an ignition source in the surrounding area. Filter 11 is designed as a replaceable cartridge.

[0037] Fig. 2 shows a further embodiment of the cooling device 1 according to the invention. Here too, the housing 3 has a connection 15 to the environment 16.

[0038] In the Fig. In the cooling device 1 shown in Figure 2, the lengths of the pipes 14 between the housing 3 and the evaporator 9 are designed to be as short as possible. It can be seen that only a short, straight pipe 14 extends between the evaporator 14 and the housing 3. Furthermore, the pipe 14 has no bend. Thus, critical leakage points outside the housing 3 can be avoided. Critical leakage points are considered to be bends, particularly those with non-smooth transitions, such as the bend designated by reference numeral 24. Such non-smooth transitions can occur particularly at connection and joint points. These points prone to leakage are therefore arranged within the housing 3.

[0039] The condenser 10 is arranged directly on the housing 3, so that, apart from the coils of the condenser 10 itself, no piping is arranged outside the housing 3. It is provided that a connection between the condenser 10 or evaporator 9 and the cooling circuit 6 is arranged within the housing 3.

[0040] The cooling device 1 also has an air circuit separation 17, through which the internal air circuit 4 and the external air circuit 5 are fluidically separated from each other. The air circuit separation 17 can be thermally insulated.

[0041] The cooling unit 1 is mounted here on an inner wall 20 of the control cabinet. Furthermore, the housing 2 of the cooling unit 1 and the inner wall 20 of the control cabinet have two aligned openings 22, 23. Thus, an internal fan 18 of the internal air circuit 4 can extract heated air from the interior 21 of the control cabinet through the first aligned opening 22. The heated air flows over the evaporator 9, and the resulting cooled air is fed back into the interior 21 of the control cabinet through the second opening 23.

[0042] The outside air circuit 5 comprises an outside fan 19. This is fluidically connected to the environment 16, here via the additional openings 25, 26. The outside fan draws air from the environment through opening 25. The cool air flows over the condenser 10, and the heated air leaves the cooling device 1 through opening 26. It can be provided that the opening 25 is fluidically connected to a cold aisle and the opening 26 is fluidically connected to a warm aisle. This allows for advantageous cooling at the condenser 10.

[0043] The Fig. The embodiment of a cooling device 1 according to the invention shown in Figure 3 largely corresponds to the one shown in Fig. 2. In contrast, the housing 3 here has a connection 15 to the outside air circuit 5. Thus, the gas discharged from the housing 3, essentially air, can be discharged to the environment 16 via the opening 26.

[0044] 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, the scope of protection being determined by the claims. List of reference symbols: 1 cooling device 2 cooling unit housings 3 Enclosure 4 Indoor air circuit 5 Outside air circuit 6 Cooling circuit 7 compressors 8 Expansion valve 9 evaporators 10 condensers 11 filters 12 Gas flow at the filter inlet 13 Gas flow at the filter outlet 14 Pipeline outside the enclosure 15 Connection 16 Surroundings 17 Air circuit separation 18 interior fans 19 outdoor fans 20 Inner wall of the control cabinet 21 Interior of the control cabinet 22 First breakthrough 23 Second breakthrough 24 Critical leak point 25, 26 Further breakthroughs

Claims

[1] Cooling device (1) for a switch cabinet, comprising an internal air circuit (4), an external air circuit (5), a cooling circuit (6) carrying a flammable refrigerant and a housing (3), wherein the cooling circuit (6) comprises at least one evaporator (9), a condenser (10), a compressor (7) and an expansion valve (8), wherein the evaporator (9) is arranged in the internal air circuit (4) and the condenser (10) is arranged in the external air circuit (5), wherein the housing (3) is designed to enclose the cooling circuit (6) in a gas-tight manner with respect to the internal air circuit (4) and the external air circuit (5) such that the evaporator (9) and the condenser (10) as well as corresponding pipes (14) are arranged outside the housing (3) as the only components of the cooling circuit (6), characterized bythat the housing (3) has a connection (15) to an environment (16) of the switch cabinet or to the outside air circuit (5), and wherein the connection (15) has a filter (11) which is designed to adsorb a combustible gas, in particular the combustible refrigerant. [2] Cooling device (1) according to claim 1, wherein a section of the pipes (14) between the housing (3) and the evaporator (9) or the condenser (10) is designed to be as short as possible, preferably the evaporator (9) and / or the condenser (10) is arranged directly on the housing (3). [3] Cooling device (1) according to claim 1 or 2, wherein the corresponding pipes (14) outside the housing (3) have no bends, preferably are straight. [4] Cooling device (1) according to claim 1, wherein the filter (11) comprises at least in some regions an active surface, in particular an adsorbing coating. [5] Cooling device (1) according to one of the preceding claims, wherein the filter (11) has at least one current-carrying element. [6] Cooling device (1) according to one of the preceding claims, wherein the filter (11) is replaceable. [7] Cooling device (1) according to one of the preceding claims, wherein the filter (11) is regenerable. [8] Cooling device (1) according to claim 7, wherein the filter (11) is regenerable by treatment with temperature, pressure and / or steam. [9] Cooling device (1) according to one of the preceding claims, wherein the internal air circuit (4) and the external air circuit (5) are separated from each other by an air circuit separation (17). [10] Cooling device (1) according to claim 9, wherein the air circuit separation (17) has a thermal insulation. [11] Cooling device (1) according to one of the preceding claims, wherein the internal air circuit (4) comprises an internal fan (18) which is fluidically connected to an inner wall (20) of the switch cabinet and is designed to suck in heated air from an interior space (21) of the switch cabinet and to supply it to the evaporator (9). [12] Cooling device (1) according to one of the preceding claims, wherein the external air circuit (5) comprises an external fan (19) which is fluidically connected to an environment (16) of the switch cabinet, in particular a cold aisle, and is designed to suck in air from the environment (16) and to supply it to the condenser (10). [13] Cooling device (1) according to one of the preceding claims, wherein the cooling device (1) is accommodated on an inner wall (20) of the switch cabinet or in a switch cabinet door. [14] Cooling device (1) according to claim 13 in conjunction with claim 12, wherein a housing (2) of the cooling device (1) and the inner wall (20) of the switch cabinet or the switch cabinet door have two mutually aligned openings (22, 23), wherein the internal fan (18) of the internal air circuit (4) is designed to suck heated air out of the interior (21) of the switch cabinet via the first aligned opening (22) and to feed it back to the interior (21) of the switch cabinet via the second opening (23) downstream of the evaporator (9).

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