Procedure for carrying out a service measure on a control housing of a refrigeration module and refrigeration module

Abstract

To perform a service operation on a control housing (10) of a refrigeration module (8), wherein at least some components of a refrigerant circuit (12) are arranged in the control housing (10), and wherein the control housing (10) is gas-tight except for a connected drain (22) and has a service port (28), a gas line (30) is connected to the service port (28), and gas is supplied to or extracted from the control housing (10) via the gas line (30). This enables pressure testing and / or purging. Furthermore, the refrigeration module (8) has at least one safety element, namely the service port (28) for the temporary connection of the gas line (30), or a safety device (40, 42, 44) for identifying whether the control housing (10) is correctly closed, or a check valve (26) which is attached to the outlet side of the drain (22).

Description

[0001] The invention relates to a method for carrying out a service measure on a control housing of a cooling module and cooling module.

[0002] The cooling module features a control housing that is gas-tight except for a connected drain line. This drain line diverts any refrigerant that escapes from the refrigerant circuit in the event of a leak into a non-safety-critical area.

[0003] Such a cooling module and a refrigerant system with such a cooling module can be found in EP 4 194 769 A1.

[0004] A refrigerant system generally comprises a refrigerant circuit that includes two heat exchangers, namely an evaporator and a condenser, as well as a compressor and an expansion valve. A refrigerant flows through the refrigerant circuit during operation.

[0005] During the service life of refrigerant systems, refrigerant leaks can occur for a variety of reasons. In the case of refrigerant systems installed inside buildings (indoor systems), these leaks can directly affect the installation room. Depending on the installation and use of the refrigerant system, several rooms or even the entire building may be exposed to escaping refrigerant from leaks. The escaping refrigerant escapes in gaseous form. This can lead to harmful or toxic concentrations for living organisms. The decomposition of some refrigerant gases on hot surfaces can also lead to toxic decomposition products. In addition, the use of highly or hardly flammable refrigerants, such as propane (R-290), poses the risk of deflagration, explosion, or fire if flammable mixtures with ignition sources are present at the same time.

[0006] To prevent refrigerant from escaping into the installation room, EP 4 194 769 A1 proposes a refrigeration module with a gas-tight control housing in which at least parts of the refrigerant circuit, and preferably the entire refrigerant circuit, are located. A drain is attached to the control housing through which the refrigerant can escape into the outside environment in the event of a leak, thus reliably preventing a dangerous or health-critical accumulation of the refrigerant, particularly in the installation room.

[0007] In view of the potentially hazardous situation in the event of a refrigerant leak, the object of the present invention is to ensure the functional reliability of the control housing and the discharge line and to further ensure that service measures can be carried out in an operationally safe manner.

[0008] DE 10 2019 105 522 A1 and the subsequently published DE 10 2022 123 440 A1 each describe a housing in which a refrigerant circuit is arranged. The housing has a service connection to which a service cartridge can be connected for flushing the interior of the housing.

[0009] DE 10 2018 113 332 A1 also discloses a flushing device for a housing of a refrigerant circuit.

[0010] The object is achieved according to the invention by a method for performing a service measure in a control housing of a refrigeration module, having the features of claim 1. At least some components of a refrigerant circuit are arranged in the control housing, and the control housing is gas-tight except for a connected discharge line and has a service connection for a gas line. To perform the service measure, a gas line is connected to the service connection, and gas is supplied to the control housing via the gas line or gas is extracted from the control housing.

[0011] The refrigeration module is part of a refrigeration system, as described, for example, in particular in the aforementioned EP 4 194 769 A1. The refrigeration system is designed, in particular, as a heat pump system, which can preferably be operated in both heating and cooling modes. The heat pump system is designed, for example, as a brine-water heat pump system or, alternatively, as an air-water heat pump system.

[0012] The drain is specifically designed as a pipe and forms a flow path from the interior of the control housing to a non-safety-critical external area, such as the environment. The drain is, in particular, an open flow path in which no active components are located, especially none that block the flow path from the control housing to the external area. In the event of overpressure in the control housing, for example, due to a refrigerant leak, the refrigerant can flow out automatically into the external area solely as a result of the overpressure.

[0013] Such a refrigerant system also requires servicing, particularly in the event of a defect, such as a refrigerant leak. If such a servicing involves checking the components of the refrigerant circuit located inside the control housing, or the refrigerant circuit as a whole, the control housing, which is usually designed as a lockable enclosure, must be opened. When opening the housing, it must be ensured that there is no danger to service personnel, for example, from refrigerant contained in the control housing.

[0014] Following the service measure, it must be ensured that the control housing is sealed gas-tight again.

[0015] In this case, gas-tight means that no gas can escape from the control housing into the immediate surroundings and thus into the installation room of the cooling module, so that no flammable gas-air mixture can arise. An escape of gas is only possible via the discharge line and then into the non-safety-critical outside area.

[0016] By providing a special, separate service connection, which is used only during service and not during normal operation, and by connecting a gas line to this service connection for the purpose of performing the service, the conditions for safe performance of the service are created and the functional reliability of the control housing and the drainage system can be verified by means of a pressure test. In all cases, gas is supplied to or extracted from the control housing via the gas line.

[0017] The service connection is, in particular, a coupling connection to which the gas line can be reversibly and repeatedly connected. For example, it is a plug-in coupling or a screw coupling. The service connection has an integrated valve that is closed during normal operation of the cooling module, ensuring that the control housing is gas-tight. The valve is only opened when a service measure is being performed, allowing gas to enter or exit via the connected gas line.

[0018] The valve is preferably a self-locking valve that is only open when the gas line is connected. Preferably, the valve opens automatically when the gas line is connected and closes automatically again when the gas line is removed. Preferably, the valve has a closure element that is pressed against a valve seat by a spring load and thus held in the closed position. When the gas line is connected, the closure element is held in an open position against the spring force. When the valve is open, flow is possible in both directions.

[0019] By providing the service connection on the control housing, service work can be carried out easily and without problems.

[0020] According to the invention, the refrigeration module, and specifically the control housing, along with the drain line, are tested for their functional reliability and functionality as part of the service measure. For this purpose, the following steps are performed, which involve a vacuum test or an overpressure test to check the tightness of the control housing and the functionality of the drain line: a) Connect the gas line to the service connection of the control box, b) tightly closing the drain, c) Setting a desired internal pressure in the control housing using the gas line, d) Check the internal pressure in the control housing.

[0021] To set the desired internal pressure, gas is added (to set an overpressure) or removed (to set a negative pressure) via the gas line. In both cases, a differential pressure is set with the ambient pressure, into which the outlet pipe leads, and thus with atmospheric pressure.

[0022] To test functional reliability, especially the tightness of the control housing and the connected drain line, the set internal pressure is checked for any change compared to the previously set internal pressure. In the event of a pressure change that exceeds a threshold, a warning message is issued, indicating that sufficient tightness cannot be guaranteed.

[0023] To ensure that the drain is tightly closed, a closure element is preferably provided, for example a shut-off valve, via which the drain is closed.

[0024] The closure element is attached in particular to an outflow opening of the drain, so that during the intended pressure test the entire drain, i.e. the entire pipe system up to the outflow opening, is also checked at the same time.

[0025] Preferably, the closure element is a temporary closure element that is installed solely for the purpose of performing the functional check. For example, the closure element is a closure plug or a closure sleeve that closes the outlet opening of the drain line.

[0026] Alternatively, a permanently installed closure element can be installed, which, however, is permanently open during normal operation of the cooling module and is only temporarily closed when the pressure test is carried out.

[0027] Following such a pressure test, in a preferred embodiment, the drain is reopened, i.e., the closure element is reopened, for example, by removing the closure plug or the end sleeve. After opening, a check is made to determine whether and how the internal pressure in the control housing returns to atmospheric pressure. This check therefore determines whether the flow path formed by the drain is clear and whether the pressure in the control housing, via the drain, returns to the ambient pressure where the drain outlet is located. In particular, a check is also made to determine whether this occurs within a specified time period, which is to be expected with an open flow path.

[0028] During the pressure test, the internal pressure is measured after a predetermined test period, and any pressure change since the desired internal pressure was set is determined. This check determines whether the previously set pressure difference between the internal pressure and atmospheric pressure is decreasing. The test duration begins, in particular, at the point at which the desired internal pressure is set and no additional gas is added or removed. If the decrease in the pressure difference exceeds a predetermined limit, a warning signal is emitted. The test duration is, for example, at least 30 seconds, preferably at least 1 minute or even several minutes, for example, 1-15 minutes. This ensures that the control housing remains leak-tight over the long term.

[0029] According to a first embodiment, an overpressure is set, and a pressure measurement is performed. For this purpose, an inert gas, in particular nitrogen, is preferably introduced. A pressure of 0.5 bar to 1 bar relative to atmospheric pressure is preferably set.

[0030] According to a second embodiment, a negative pressure is set, and a negative pressure measurement is performed. Preferably, a negative pressure of at least 0.5 bar relative to atmospheric pressure is set.

[0031] Particularly in the event of a detected refrigerant leak, access to the refrigerant circuit is required as part of the service measure. A refrigerant leak can be detected, for example, using a refrigerant detector or by other means. Specifically to rule out any danger to service personnel in such a case, a preferred embodiment provides for the control housing to be purged with a purge gas for a predetermined purge time. For this purpose, the purge gas, in particular an inert gas such as nitrogen, is introduced into the control housing via the gas line. Unlike with pressure testing, the outlet is open, allowing the purge gas to flow through the control housing, thereby discharging any remaining refrigerant.

[0032] The purging duration, i.e. the period of time during which the purging gas is introduced, and / or a purging volume, i.e. the amount of purging gas that is introduced, is preferably predetermined, in particular depending on the volume of the control housing and the pipe system of the discharge connected to it.

[0033] According to an optional embodiment, purging with the purge gas is carried out and, in particular, controlled as a function of the current refrigerant concentration. The refrigerant concentration is preferably detected using a refrigerant detector, which is preferably only temporarily attached to the discharge line and, in particular, only for or during the purge process. The detector is preferably attached in the region of the discharge opening of the discharge line, preferably directly at the discharge opening. At the discharge opening, the gas escapes into the non-safety-critical area (environment). This measure adapts the required quantity of purge gas to the current situation and requirements, while simultaneously ensuring that the control housing and the discharge line are sufficiently purged.For example, flushing is stopped when the refrigerant concentration falls below a specified limit.

[0034] The object is further achieved according to the invention by a refrigeration module having the features of claim 5. The refrigeration module has a control housing in which at least some components of a refrigerant circuit are arranged, wherein the control housing is gas-tight except for a connected discharge line and wherein the control housing has at least one and preferably several of the following safety elements: i.) the previously described service connection for the temporary connection of the gas line, ii.) a safety device to identify whether the control housing is correctly closed, iii.) a non-return valve which is installed on the downstream side of the discharge line.

[0035] Preferably, a protective grille is also attached to the outlet opening, which is designed as a weather, insect, or small animal protection grille to prevent the penetration of unwanted foreign bodies.

[0036] The function and mode of operation as well as preferred designs of the service connection have already been explained in more detail.

[0037] The safety device generally ensures that after a service measure or during initial installation, operation of the cooling module and thus the entire refrigerant system is only possible if the control housing is correctly closed and thus sealed against the environment.

[0038] The non-return valve ensures that no unwanted foreign matter and / or fluids / gases from the environment can penetrate the control housing. The penetration of unwanted foreign matter can be prevented additionally or alternatively by the aforementioned protective grille. At the same time, the non-return valve is designed to automatically open the flow path to the outside in the event of overpressure in the control housing.

[0039] With regard to the previously described functionality check by means of pressure testing or with regard to flushing the control housing and the drain line, a particularly mobile service module is expediently designed, which has a gas line for connection to the service connection and a pump, whereby gas can be supplied to or extracted from the control housing via the gas line via the pump. Mobile here means that the service module is not an integral part of the refrigerant system or the refrigeration module. In particular, it is a portable service module that can be carried by one person. The mobile service module is therefore used to carry out the service work in the event of a service call.

[0040] A refrigerant detector is conveniently mounted on the discharge line, and in particular on its outlet opening, to detect the concentration of refrigerant in the gas flowing out of the discharge line. As previously described, this detector is used particularly during purging.

[0041] The safety device comprises an electrical switch designed to only emit a release signal when the control housing is correctly closed. This release signal is transmitted, in particular, to a control unit, which controls the operation of the refrigerant circuit, in particular the refrigeration module and the entire refrigerant system. The control unit preferably operates the refrigerant circuit only when the release signal is present.

[0042] Alternatively or additionally, the safety device features an optical control element that visually indicates an improperly closed control housing. This allows the installer to immediately determine whether the control housing is correctly installed and closed.

[0043] The control housing is typically located within a system housing of the refrigerant system. The system housing itself, like the control housing, has at least one closable opening through which access to the interior of the system housing is possible.

[0044] The safety device of the control housing has a locking mechanism that prevents correct assembly, in particular, closing of the system housing, if the control housing is not properly closed. For this purpose, the locking mechanism has, in particular, a mechanical locking element with a locking bar, which is designed such that, if the control housing is not properly closed, it blocks a fastening point for the system housing, preventing the system housing or a housing cover from being correctly positioned.

[0045] The check valve is preferably designed to prevent gas from entering the control housing via the outlet opening. For this purpose, the check valve is preferably designed in the manner of a simple check valve, which is mounted within the discharge line, in particular in a pivoting manner. The check valve automatically opens the flow path to the outside and blocks it in the direction of the control housing. Such a check valve takes into account a hypothetical hazardous situation in which, in the event of a refrigerant leak, an ignitable mixture accumulates at the outlet opening and can ignite if an ignition source is present. The check valve prevents a flame from flashing back into the interior.

[0046] The non-return valve protects the drain against the ingress of foreign objects and / or small animals. This prevents the drain from becoming at least partially blocked over time, which would impair its functionality. For this purpose, a grid is installed specifically as weather protection and / or small animal protection, thus preventing small animals, especially insects, from entering the drain.

[0047] An exemplary embodiment of the invention is explained in more detail below with reference to the single figure. This shows a schematic, highly simplified representation of a refrigeration module as part of a refrigeration system.

[0048] A refrigerant system 2, shown in detail in the figure, is an indoor system arranged inside a building 4. The refrigerant system 2 is, in particular, a heat pump system. It has a system housing 6 in which a refrigeration module 8 is arranged. This has a control housing 10 in which at least some components of a refrigerant circuit 12 are mounted. These components are, in particular, at least one (first) heat exchanger, a compressor, and an expansion device. In the case of a heat pump system and in heating mode, the first heat exchanger is a condenser.

[0049] A consumer circuit 14 with at least one consumer is connected to the first heat exchanger. This is, in particular, a space heater and / or a domestic hot water storage tank or buffer tank. Consumer circuit 14 is indicated in the figure by only two lines.

[0050] The heat pump system can be an air-to-water heat pump system or a brine-to-water heat pump system. In an air-to-water heat pump system, a second heat exchanger (evaporator in heating mode) of the refrigerant circuit 12 is typically mounted outside the control housing 10. In the case of a brine-to-water heat pump system, this second heat exchanger is mounted specifically inside the control housing 10. A hydraulic circuit referred to as the brine circuit 16 is attached to this second heat exchanger, which is again indicated in the figure by only two lines.

[0051] The control housing 10 is, in particular, a two-part housing with a base part 18 and a cover part 20, which can be reversibly connected to one another and tightly closed. The two parts are preferably monolithic parts and in particular made of plastic, specifically a foamed plastic. A discharge line 22 is attached to the control housing 10, which is designed as a pipe and forms a flow path from the interior of the control housing 10 to a non-safety-critical area. In the exemplary embodiment, the non-safety-critical area is formed by the environment U outside the building 4. In this non-safety-critical area, the discharge line 22 has an outflow opening 24.

[0052] In the exemplary embodiment, a check valve 26 is arranged on the discharge line 22 as a check device or at least as part of a check device. The discharge line 22 is, in particular, an open pipe that forms an open flow path from the control housing 10 to the environment U. The check valve 26 only prevents inflow in the opposite direction. This opens automatically as soon as excess pressure prevails in the control housing 10.

[0053] Furthermore, a service connection 28 is attached to the control housing 10, which in particular has a closable valve.

[0054] A gas line 30 can be connected to this service connection 28 for servicing purposes and is also connected in the figure. In the exemplary embodiment, this line is connected to a service module 32, via which gas can be introduced into the control housing 10 or extracted from it. For this purpose, the service module 32 has at least one suitable pump 34, which is designed, for example, as an overpressure pump and / or vacuum pump. In addition, a pressure measuring device 36 is preferably arranged within the service module 32, via which the internal pressure prevailing in the control housing 10 can be measured. Alternatively, a pressure measuring device 36 can also be mounted within the control housing 10.

[0055] In the figure, a closure element 38 is also attached to the outlet opening 24. This is, in particular, a closure plug or a closure sleeve, which temporarily closes the outlet opening 24. This element is preferably not attached during normal operation. It is only attached when the service measure is performed.

[0056] Finally, several safety devices are also shown in the figure. First, an (optional) electrical switch 40 is shown as a first safety device, which is designed, for example, as a magnetic switch or a pressure switch. This switch checks and ensures that the control housing 10, i.e., the base part 18 and the cover part 20, are correctly connected to one another, so that the control housing 10 is correctly and thus tightly closed. In this case, the switch emits a corresponding release signal, in particular to a control device (not shown in detail here), via which the operation of the refrigerant system 2 is controlled.

[0057] An (optional) mechanical locking mechanism 42 is shown as a second safety device. This mechanism comprises a mechanical latch, lever, or other mechanical elements designed to prevent the system housing 6 from being closed and / or correctly installed unless the control housing 10 is properly closed.

[0058] Finally, an optical control element 44 is shown as a further safety device, which provides a visual indication of whether the control housing 10 is correctly closed. This can be a passive element, for example, a color coding that can be identified when the control housing 10 is correctly closed or not. Alternatively, it can be an active light-emitting element, for example, an LED, which emits a corresponding active optical signal if the control housing 10 is not correctly closed.

[0059] To verify the functional reliability of the control housing 10 and the connected discharge line 22, a pressure test is performed as a service measure and therefore only in the case of a temporary service case. This involves an overpressure test and / or a vacuum test. The procedure is as follows: First, the gas line 30 is connected to the service connection 28. This preferably automatically opens up a flow path into the interior of the control housing 10. Before or after this, the outlet opening 24 is sealed. For this purpose, in particular, the closure element 38 is attached. A desired internal pressure, for example an overpressure or alternatively a negative pressure, is then set in the control housing 10 via the pump 34. Once the specified internal pressure is reached, the pump 34 is switched off. The control housing 10 with the discharge line 22 connected to it defines - in the described application together with the gas line 30 - a sealed control volume. The set internal pressure is monitored via the pressure measuring device 36 either continuously or only at discrete times and in particular after a specified test duration.If an inadmissible pressure change compared to the previously set internal pressure is detected during the test period, a warning signal is issued to indicate that the control housing 10 is not tight.

[0060] Following the pressure test, the flow path is reopened via discharge line 22, and in particular, the closure element 38 is removed. Subsequently, a check is carried out, in particular using the pressure measuring device 36, to determine whether the atmospheric pressure prevailing in the environment U is restored in the control housing 10. This check therefore determines whether the flow path defined via discharge line 22 is functional. In particular, the time required for atmospheric pressure to be restored is monitored and compared with the expected time period with the flow path open.

[0061] In the case of a negative pressure test and a design variant in which the check valve 24 is installed, it must be deactivated, i.e., the check valve 24 must be locked in a position that allows the flow path inward into the control housing 10. This is not necessary for a design variant without the check valve 24.

[0062] Overall, therefore, a two-stage test is carried out, which checks both the tightness of the control housing 10 and the functionality of the flow connection to the environment via the discharge line 22.

[0063] If it is necessary to open the control housing 10 as part of a service measure, in particular after a refrigerant leak has been detected, the control housing 10 is first flushed with a purge gas before being opened. For this purpose, a gas, in particular an inert gas such as nitrogen, is pumped into the control housing 10 via the pump 34, similar to the pressure test. This gas flows through the control housing 10 and exits again via the outlet line 22, which, unlike the pressure test, is not closed. After sufficient purging, the control housing 10 can be opened safely. In particular, purging is continued until the maximum permissible refrigerant concentration is not reached. For this purpose, an (optional) refrigerant detector 46 is attached, in particular to the outlet line 22, specifically in the area of ​​the outlet opening 24. This is preferably only attached temporarily and during the purging process.

[0064] Overall, the measures described here implement a multitude of safety functions that ensure that, during normal operation of the refrigerant system 2 and in the event of a refrigerant leak, the escaping refrigerant is reliably drained away and that no safety-critical or health-endangering refrigerant accumulation occurs at the installation site of the refrigeration module 8. This is achieved, on the one hand, by the described functional test of the control housing 10 using the described pressure test and, furthermore, by the various safety devices that ensure the tight closure of the control housing 10.

[0065] Finally, the flushing measure also ensures that the service personnel are not exposed to any danger. List of reference symbols 2 Refrigerant system 4 buildings 6 system housings 8 Cooling module 10 control housings 12 Refrigerant circuit 14 Consumer group 16 brine circuit 18 Basic part 20 lid part 22 Derivation 24 Outlet opening 26 Check valve 28 Service connection 30 gas pipeline 32 Service module 34 Pump 36 Pressure measuring device 38 locking element 40 switches 42 Locking mechanism 44 optical control element 46 Refrigerant detector U environment

Claims

[1] Method for carrying out a service measure in a control housing (10) of a refrigeration module (8), wherein at least some components of a refrigerant circuit (12) are arranged in the control housing (10), and wherein the control housing (10) is gas-tight except for a connected discharge line (22) and has a service connection (28), wherein to carry out the service measure, a gas line (30) is connected to the service connection (28) and gas is supplied to the control housing (10) or extracted from it via the gas line (30), wherein the following steps are carried out to check the functionality of the refrigeration module (8) a) Connect the gas line (30) to the service connection (28) of the control housing (10), b) tightly closing the drain (22), c) Setting a desired internal pressure in the control housing (10) using the gas line (30), d) Check the internal pressure in the control housing (10). [2] Method according to the preceding claim, in which during the functional check a closure element (38) for closing the discharge line (22) is only temporarily attached and in particular at an outflow opening (24) of the discharge line (22). [3] Method according to one of the two preceding claims, in which the discharge line (22) is opened again and it is checked how the internal pressure adjusts to the atmospheric pressure. [4] Method according to one of the preceding claims, wherein in step d) after a predetermined test period a pressure change since setting the desired internal pressure is determined. [5] Refrigeration module (8) with a control housing (10) in which at least some components of a refrigerant circuit (12) are arranged, and wherein the control housing (10) is gas-tight except for a connected discharge line (22),characterized by that the control housing (10) has at least one and preferably several of the following security elements: i. a service connection (28) for the temporary connection of a gas line (30) through which a gas can be supplied to or extracted from the control housing (10), ii. a safety device (40, 42, 44) for identifying whether the control housing (10) is correctly closed, iii. a non-return device (26) which is attached to the outflow side of the discharge line (22); wherein one or more of the following features is / are met: - the safety device has an electrical switch (40) which is designed to only emit a release signal when the control housing (10) is correctly closed, - the safety device has an optical control element (44) which optically indicates an incorrectly closed control housing (10), - the control housing (10) is mounted in a lockable system housing (6) and the safety device has a locking mechanism (42) which prevents correct assembly of the system housing (6) if the control housing (10) is not correctly closed. [6] Cooling module (8) according to the preceding claim, wherein a particularly mobile service module (32) is provided, which has a gas line (30) for connection to the service connection (28) and a pump (34) via which a gas can be supplied to or extracted from the control housing (10) with the aid of the gas line (30). [7] Refrigeration module (8) according to one of the two preceding claims, wherein a refrigerant detector (46) is attached to the discharge line (22), in particular to its outflow opening (24). [8] Refrigeration module (8) according to one of claims 5 to 7, wherein the non-return device (26) automatically blocks the discharge line (22) against gas ingress, especially a flashback of a flame and / or secures it against the ingress of small animals.

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