Cooling device for air conditioning of switchgear cabinets and corresponding switchgear cabinet devices

Abstract

The present invention relates to a cooling device for air conditioning of a switchgear cabinet. The cooling device (1) has a primary circuit (2) using a flammable refrigerant and has a condenser (3) arranged in an external air circuit (4) of the cooling device (1). The cooling device (1) has an evaporator (5) in an internal air circuit (10) fluidly separated from the external air circuit (4). The cooling device (1) has a secondary circuit (6) which uses a non-flammable refrigerant and has the evaporator (5) and a liquid-liquid heat exchanger (7) arranged in the external air circuit (4), and uses the liquid-liquid heat exchanger (7) to transfer heat from the non-flammable refrigerant to the flammable refrigerant. A corresponding switchgear cabinet device is also described.

Description

Technical Field

[0001] The present invention is based on a cooling device for air conditioning of a switchgear cabinet and a corresponding switchgear cabinet device. The cooling device has a primary circuit with a flammable coolant and a condenser arranged in an external air circuit of the cooling device.

Background Art

[0002] Further, the cooling device has an evaporator in an internal air circuit, and the internal air circuit is fluidly separated from the aforementioned external air circuit. The internal air circuit may have an air inlet opening and an air outlet opening, and the air inlet opening and the air outlet opening open into the internal space of the housing of the switchgear cabinet. The external air circuit may be open around the aforementioned cooling device and switchgear cabinet device using its air intake and exhaust ports. Therefore, in the external air circuit, there may be a flow of outside air passing through the external air circuit, and for this purpose, it has a fan. The flow of outside air passing through the external air circuit may act on the condenser, and for this purpose, the condenser is configured as, for example, a gas-liquid heat exchanger. In the internal air circuit, the air circulating in the internal air circuit may act on the evaporator arranged in the internal air circuit. The evaporator may be designed as an air-liquid heat exchanger. This type of cooling device is well known from German Patent Application Publication No. 10 2018 109 604.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Directive 2006 / 42 / EC (Machinery Directive) requires that there be no risk of explosion or fire due to the gases used in the machinery, and that individual components should be assumed to fail. Therefore, in the case of the cooling device of the switchgear cabinet, if a leak is assumed to exist in the refrigerant conveyance section, it should be assumed that the flammable gas (refrigerant) may flow into the switchgear cabinet and ignite the internal accessories that generate arcs during operation. Without a safety function to reliably prevent this, the cooling device of the switchgear cabinet using flammable refrigerant cannot meet the aforementioned Machinery Directive, nor can it operate while ensuring the necessary safety for the end user.

[0005] In a switchgear cabinet device well-known from the prior art, when a leak is detected and / or when a flammable refrigerant penetrates into the interior of the switchgear cabinet, for example, it is necessary to operate to close the partition between the internal circuit of the cooling device and the interior of the switchgear cabinet so that the refrigerant cannot penetrate into the interior of the switchgear cabinet any further. For example, it requires different closing members that are actively driven, and has the disadvantage that the implementation is relatively complicated.

[0006] Therefore, the object of the present invention is to further develop the cooling device described at the beginning and incorporate all the safety measures required in accordance with the Machinery Directive, so that as a result, there is no need to adapt it to other parts of the switchgear cabinet, especially to the housing of the switchgear cabinet.

Means for Solving the Problem

[0007] This object is achieved by a cooling device having the features of claim 1. The corresponding switchgear cabinet device is the subject of independent claim 16. Advantageous embodiments are the subject of the dependent claims respectively.

[0008] Accordingly, in the case of this cooling device, a non-flammable refrigerant is used, and it has an evaporator and a liquid-liquid heat exchanger arranged in an external air circuit, and is provided with a secondary circuit that uses the liquid-liquid heat exchanger to transfer heat from the aforementioned non-flammable refrigerant to a flammable refrigerant.

[0009] The cooling circuit of the cooling device is separated into a primary circuit and a secondary circuit, and by using a non-flammable refrigerant in the secondary circuit, even if a leak occurs in one of these two refrigerant circuits, the flammable refrigerant cannot flow into the internal air circuit, and as a result, this flammable refrigerant cannot enter the internal space of the switchgear cabinet.

[0010] This liquid-liquid heat exchanger may be a condenser of the secondary circuit and also an evaporator of the primary circuit. This liquid-liquid heat exchanger may be designed as a plate heat exchanger.

[0011] This primary circuit may be designed as an active compressor refrigeration circuit equipped with a compressor and an expansion member.

[0012] This primary circuit may be arranged in the cooling device in a state fluidly separated from the internal air circuit.

[0013] This primary circuit may be completely ventilated around the cooling device. In particular, the primary circuit may be completely arranged within the external air circuit.

[0014] The secondary circuit may be a passive refrigerant circuit, and is preferably a natural circulation type refrigerant circuit driven by a geodetic height difference. This secondary circuit may be designed as, for example, a heat pipe, or may be provided with a heat pipe. The non-flammable refrigerant may be, for example, carbon dioxide, or may contain carbon dioxide.

[0015] The cooling device may also include a tertiary circuit. In this tertiary circuit, the condenser of the primary circuit is the condenser of the tertiary circuit, and the evaporator of the secondary circuit is the evaporator of the tertiary circuit.

[0016] The condenser of the primary circuit and / or the condenser of the tertiary circuit may be a dual-circuit gas-liquid heat exchanger in which two liquid conveyance lines are fluidly separated from each other.

[0017] The evaporator of the secondary circuit and the evaporator of the tertiary circuit may be a dual-circuit gas-liquid heat exchanger in which two liquid conveyance lines are fluidly separated from each other.

[0018] This tertiary circuit may contain a non-flammable refrigerant such as carbon dioxide, or may be a non-flammable refrigerant.

[0019] This tertiary circuit may be a passive refrigerant circuit, preferably a natural circulation refrigerant circuit driven by the difference in geodesic altitude. The tertiary circuit may be designed as a heat pipe, for example, or may include a heat pipe.

[0020] In the cooling device, a fan may be arranged in each of the external air circuit and the internal air circuit. When the fan is provided in the external air circuit, the condenser may receive the action from the air conveyed through the external air circuit. When the fan is provided in the internal air circuit, the evaporator may receive the action from the air conveyed through the internal air circuit.

[0021] In a switchgear cabinet housing and a switchgear cabinet device provided with a cooling device of the above-described type, the air around the switchgear cabinet device is conveyed through the external air circuit, and the air received into the internal space of the switchgear cabinet housing is conveyed through the internal air circuit. The internal air circuit and the external air circuit may be fluidly separated from each other so that air exchange between the external air circuit and the internal air circuit cannot be performed.

Brief Description of the Drawings

[0022] Exemplary embodiments of the present invention will be described with reference to the following figures:

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0023] FIG. 1 shows an exemplary embodiment of a switchgear cabinet device 100 including a housing 200 of a switchgear cabinet and a cooling device 1 attached to a side surface portion of the housing 200 of the switchgear cabinet. Arranged inside the housing 200 of the switchgear cabinet are components 300 that radiate heat and may generate arcs in some cases. In the components 300, a combustible refrigerant accumulated in the internal space 13 of the housing 200 of the switchgear cabinet may be ignited by an arc generated, for example, during the switching operation of the switching device 300.

[0024] The cooling device 1 has an internal air circuit 10. Through the internal air circuit 10, the air received in the internal space 13 of the housing 200 of the switchgear cabinet is conveyed using a fan 12. In the upper region of the housing 200 of the switchgear cabinet, the heated air is introduced into the internal air circuit 10, while in the lower region of the housing 200 of the switchgear cabinet, the air flows out of the internal air circuit 10 and returns to the internal space 13 of the housing 200 of the switchgear cabinet. When passing through this internal air circuit 10, the air acts on the evaporator 5. In this case, the evaporator 5 is configured as a gas-liquid heat exchanger of a compressor circuit, and as a result, the air is cooled.

[0025] In the external air circuit 4, the cooling device 1 has a condenser 3, and the condenser 3 is acted upon by the air surrounding the switchgear cabinet device 100 flowing through the external air circuit 4 and is similarly configured as a gas-liquid heat exchanger.

[0026] In contrast to the cooling device known from the prior art, in the cooling device 1 according to the invention, the evaporator 5 of the internal air circuit 1 is not fluidly connected to the condenser 3 of the external air circuit 4 using a common refrigerant circuit. Instead, a primary circuit 2 having a condenser 3 and a secondary circuit 6 having an evaporator 5 are provided, and the primary circuit 2 and the secondary circuit 6 are thermally coupled to each other in a fluidly separated state using a liquid-liquid heat exchanger 7.

[0027] To better understand the fluid interconnections of an exemplary cooling device according to the present invention, reference is made to the block diagram according to FIG. 2. In this figure, the horizontal dashed line indicates an airtight separation between the external air circuit 4 and the surroundings of the switchgear cabinet device 100, and the internal air circuit 10 and the internal space 13 of the housing 200 of the switchgear cabinet. Thus, the primary circuit 2, designed as a compressor circuit with a compressor 8 and an expansion member 9, is completely arranged within the external air circuit 4. As a result, even if a leak occurs due to the internal air circuit 10 and the external air circuit 4 being separated, the combustible refrigerant cannot enter the internal space 13 of the internal air circuit 10 or the housing 200 of the switchgear cabinet with components 300 housed therein, so the primary circuit 2 can contain the combustible refrigerant. As is well known from the prior art, the primary circuit 2 has a gas-liquid heat exchanger that is acted upon by the air from the fan 12 and has the function of a condenser. Different from the well-known cooling device 1, the evaporator of the primary circuit 2 is a liquid-liquid heat exchanger such as a plate heat exchanger, and using this liquid-liquid heat exchanger, the primary circuit 2 is thermally coupled to the secondary circuit 6. The secondary circuit 6 has a further gas-liquid heat exchanger 5 that is similarly acted upon by the air from the fan 12, and the air of the fan 12 is guided through the internal air circuit 10. The secondary circuit 6 is filled with a non-combustible refrigerant so that the refrigerant that enters the internal space 13 and is discharged in case of a leak cannot be ignited by the arc of the components 300. Regarding the secondary circuit 6, the liquid-liquid heat exchanger 7 forms a condenser.

[0028] To further optimize the efficiency of the cooling device 1, the condenser 3 and the evaporator 5 are each of a dual-circuit design, and in either case, one of the two circuits of the condenser 3 and the evaporator 5 forms a tertiary circuit. Both the tertiary circuit 11 and the secondary circuit 6 are preferably designed as natural circulation refrigerant circuits driven by the difference in geodesic altitude. In one embodiment, the secondary circuit 6 and / or the tertiary circuit may be designed as a heat pipe.

[0029] The features of the present invention disclosed in the above description, drawings, and claims may be essential, either individually or in any desired combination, for the implementation of the present invention.

Description of Reference Numerals

[0030] 1 Cooling device 2 Primary circuit 3 Condenser 4 External air circuit 5 Evaporator 6 Secondary circuit 7 Heat exchanger 8 Compressor 9 Expansion member 10 Internal air circuit 11 Tertiary circuit 12 Fan 13 Internal space 100 Switchgear cabinet device 200 Housing of switchgear cabinet 300 Parts

Claims

1. A cooling device (1) for air conditioning a switchgear cabinet, wherein the cooling device (1) has a primary circuit (2) using a flammable refrigerant and has a condenser (3) arranged in an external air circuit (4) of the cooling device (1), the cooling device (1) has an evaporator (5) in an internal air circuit (10) fluidly separated from the external air circuit (4), the cooling device (1) has a secondary circuit (6) which uses a non-flammable refrigerant and has an evaporator (5) and a liquid-liquid heat exchanger (7) arranged in the external air circuit (4), and transfers heat from the non-flammable refrigerant to the flammable refrigerant using the liquid-liquid heat exchanger (7). The cooling device (1) is characterized by this.

2. The cooling device (1) according to claim 1, wherein the liquid-liquid heat exchanger (7) is a condenser of the secondary circuit (6) and an evaporator of the primary circuit (2).

3. The cooling device (1) according to claim 1 or 2, wherein the liquid-liquid heat exchanger (7) is designed as a plate heat exchanger.

4. The cooling device (1) according to any one of claims 1 to 3, wherein the primary circuit (2) is designed as an active compression-type refrigerant circuit provided with a compressor (8) and an expansion member (9).

5. The cooling device (1) according to any one of claims 1 to 4, wherein the primary circuit (2) is arranged in the cooling device (1) in a state fluidly separated from the internal air circuit (10).

6. The cooling device (1) according to any one of claims 1 to 5, wherein the primary circuit (2) is completely ventilated around the cooling device (1).

7. The cooling device (1) according to claim 6, wherein the primary circuit (2) is completely arranged within the external air circuit (4).

8. The cooling device (1) according to any one of claims 1 to 7, wherein the secondary circuit (6) is a passive refrigerant circuit, preferably a natural circulation-type refrigerant circuit driven by a difference in geodesic altitude, such as a heat pipe.

9. The cooling device (1) according to any one of claims 1 to 8, wherein the non-flammable refrigerant contains carbon dioxide.

10. comprising a tertiary circuit (11), The cooling device (1) according to any one of claims 1 to 9, characterized in that the condenser (3) of the primary circuit (2) is the condenser of the tertiary circuit (11), and the evaporator (5) of the secondary circuit (6) is the evaporator of the tertiary circuit (11).

11. The cooling device (1) according to claim 10, characterized in that the condenser (3) of the primary circuit (2) and / or the condenser (3) of the tertiary circuit (11) is a double-circuit gas-liquid heat exchanger in a state where two liquid conveyance lines are fluidly separated from each other.

12. The cooling device (1) according to claim 10 or 11, characterized in that the evaporator (5) of the secondary circuit (6) and the evaporator (5) of the tertiary circuit (11) are double-circuit gas-liquid heat exchangers in a state where two liquid conveyance lines are fluidly separated from each other.

13. The cooling device (1) according to any one of claims 10 to 12, characterized in that the tertiary circuit (11) contains a non-flammable refrigerant such as, for example, carbon dioxide.

14. The cooling device (1) according to any one of claims 10 to 13, characterized in that the tertiary circuit (11) is a passive refrigerant circuit, preferably a natural circulation refrigerant circuit driven by a difference in geodesic altitude, such as a heat pipe.

15. The cooling device (1) according to any one of claims 10 to 13, characterized in that a fan (12) is arranged in each of the external air circuit (4) and the internal air circuit (10), and the evaporator (5) or the condenser (3) receives the action from the air conveyed through each of the external air circuit (4) and the internal air circuit (10) by using the fan (12).

16. In a switchgear cabinet device (100) comprising the housing (200) of the switchgear cabinet and the cooling device (1) according to any one of claims 1 to 15, The switchgear cabinet device (100) is characterized in that the air around the switchgear cabinet device (100) is conveyed through the external air circuit (4), and the air received in the internal space (13) of the housing (200) of the switchgear cabinet is conveyed through the internal air circuit (10).

Images