Refrigeration system and refrigerant module

Description

[0001] The invention relates to a refrigerant system, which is designed in particular for indoor installation, i.e., as a so-called indoor system. Such a refrigerant system generally comprises a refrigeration circuit which includes two heat exchangers, namely an evaporator and a condenser, as well as a compressor and an expansion valve. A refrigerant flows in the refrigeration circuit during operation.

[0002] During the service life of refrigerant systems, refrigerant leaks can occur for a variety of reasons. In the case of 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 affected by escaping refrigerant from leaks. The escaping refrigerant usually escapes in gaseous or sometimes liquid form, which then re-gasifies. This can lead to concentrations that are harmful or toxic to living beings. Furthermore, the decomposition of some refrigerant gases on hot surfaces can produce toxic decomposition products. Additionally, the use of highly or highly flammable refrigerants poses a risk of deflagration, explosion, or fire if flammable mixtures interact with ignition sources simultaneously.

[0003] German patent DE 10 2016 112 851 A1 describes a refrigerant system in which the refrigeration circuit is arranged within a housing where a negative pressure relative to the environment is maintained. This is intended to prevent refrigerant gas from escaping into the environment.

[0004] According to DE 20 2016 103 305 U1, the refrigeration circuit is also arranged in a housing containing a pressure sensor that monitors the internal pressure. A pressure increase is identified as a leak in the refrigeration circuit, and an exhaust system draws outside air into the housing, while the refrigerant-laden air is expelled to the outside, into the surrounding environment.

[0005] DE 10 2018 113 332 A1 also provides for flushing a housing of a refrigeration circuit, with an outlet leading to the environment outside the building.

[0006] From EP 3 792 572 A1 a safety purging device for a brine-to-water heat pump can be taken, which has a capsule housing in which the components of the refrigeration circuit are arranged and to which an air duct leading to the outside and / or an internal outlet led via an adsorber for refrigerant occurring in the event of a leak is attached.

[0007] FR 2 827 948 A1 also describes a heat pump with a housing to which an air duct leading to the outside is connected.

[0008] EP 3 199 883 A1 shows a heat pump with an outdoor unit installed outdoors.

[0009] EP 3 767 186 A1 shows a safety device for an outdoor unit of a heat pump, wherein the refrigeration circuit is arranged in the outdoor unit and the outdoor unit is connected to the building via hydraulic lines, wherein the hydraulic lines running outdoors have shut-off valves and a vent.

[0010] Based on this, the invention aims to provide a refrigerant system and a refrigerant module that are easy to install and at the same time ensure a high level of protection against refrigerant leakage and against the accumulation of critical refrigerant concentrations in the installation room.

[0011] The problem is solved according to the invention by a refrigerant system specifically for indoor installation, comprising a refrigeration circuit with the features of claim 1. The refrigeration circuit has two heat exchangers, namely an evaporator and a condenser, as well as a compressor and an expansion valve. A refrigerant circulates in the refrigeration circuit during operation. In the installed state, at least one hydraulic circuit is connected to the refrigeration circuit, in which a liquid transfer medium, in particular a liquid heat transfer fluid, typically water, optionally with additives, is circulated. The refrigerant system generally has a housing in which at least some, and preferably all, components of the refrigeration circuit, as well as other components, are arranged.

[0012] The other components are hydraulic or electrical components required and used for the operation of the refrigerant system. These include, for example, circulation pumps, piping, an expansion vessel, valves, and a storage tank, such as a domestic hot water tank. With regard to the electrical components, this primarily includes a system control unit with an operator terminal.

[0013] Furthermore, a sealed control housing is arranged within the system casing, containing the compressor, expansion valve, and at least one, and preferably both, heat exchangers of the refrigerant circuit. The control housing encloses a control volume that serves to collect refrigerant that has escaped from the refrigerant circuit. A drain for the controlled removal of gas from the control volume is also connected to the control housing. When the refrigerant system is installed, the system casing is located in a room. The drain is also connected to an external area outside the installation room.

[0014] In a preferred embodiment, the vent is connected in a lower section, specifically in the lower third of the control housing, and in this section forms a connection to the interior of the control housing. This is based in particular on the consideration that commonly used refrigerants are heavier than atmospheric air and therefore accumulate in the lower section in the event of a leak. The arrangement in the lower section ensures efficient venting of the refrigerant.

[0015] A particular advantage of this refrigerant system is that the control housing is arranged as a self-contained, integral unit within the larger system housing, thus forming an independent sub-module of the system. This allows for simplified installation, maintenance, and replacement of this separate unit.

[0016] The hermetically sealed control housing, within which the refrigeration circuit is located, reliably prevents refrigerant from escaping into the installation room. Apart from the drain, the control housing has no other openings that would allow gas exchange with the environment, not even a closable one. This means the only connection for refrigerant flow is via the drain. In the event of a leak, refrigerant can accumulate inside the control housing. In such a case, the connected drain releases the refrigerant from the control housing to the outside, outside the installation room. The refrigerant is therefore reliably discharged to a safe external environment. No negative pressure is created inside the control housing. The drain ensures a permanently open connection to the outside.

[0017] The outdoor area refers specifically to the area outside a building. Alternatively, the outdoor area can also be a part of a building where a critical accumulation of refrigerant is reliably prevented, for example, by sufficient room size or adequate ventilation. This effectively prevents critical refrigerant accumulation in the installation room. Therefore, active ventilation in the installation area of ​​the refrigerant system is unnecessary, thus minimizing installation effort.

[0018] The control enclosure creates an explosion-proof area overall. This is particularly due to the fact that there are no effective ignition sources inside the control enclosure.

[0019] When the term "refrigerant system" is used here, it generally refers to a system in which heat is transported from a heat source to a heat sink via a refrigeration cycle, absorbing energy in the process. The refrigeration system is preferably a heat pump system, which provides heat on one side. Alternatively, it can be a refrigeration system, which provides cooling on the other side. At least one (first) hydraulic circuit is connected to the refrigeration cycle. This circuit is designed as the consumer circuit and contains a transfer medium – depending on the system type, either a heat transfer medium or a cooling medium – which circulates and supplies at least one consumer with heat (heat sink) or cooling (cold sink, or heat source for the refrigeration cycle).

[0020] Depending on the system type, a second hydraulic circuit is connected to the refrigeration circuit when installed. This can be a water circuit (in a water-to-water refrigerant system) or a brine circuit. For the sake of generality, both variants will be referred to as a brine circuit and a brine-to-water refrigerant system. This second hydraulic circuit is connected to the second heat exchanger, or, in the case of a heat pump, to the evaporator.

[0021] The second heat exchanger, in one configuration, is an air / refrigerant heat exchanger, which is designed for heat transfer using humid air. Such systems are subsequently also referred to as air / water refrigerant systems.

[0022] Preferably, some of the components of at least one hydraulic circuit are already arranged within the system housing, such as pumps and valves. The system housing generally has an interface to which the remaining components of the at least one hydraulic circuit can be connected, specifically piping and at least one consumer. In other words, the system housing is a pre-assembled unit that only needs to be connected to piping, for example, of the consumer circuit.

[0023] In the configuration as an air / water refrigerant system, where one of the two heat exchangers is designed as an air / refrigerant heat exchanger, this heat exchanger is preferably arranged within an air duct. In a preferred embodiment, the exhaust pipe terminates in this air duct. Since the air duct is generally connected to the outside, specifically to the environment outside the building, this measure ensures a reliable airflow connection to the outside with minimal installation effort.

[0024] To ensure reliable refrigerant discharge in the event of a leak, a preferred embodiment provides for a permanently open flow connection to the outside via the discharge duct. In the event of a leak, refrigerant can therefore automatically flow to the outside via this duct. The discharge duct thus acts as a passive safety device, reliably discharging the gases independently of any other active measures, such as measuring the refrigerant concentration. This ensures a high level of passive system safety. The discharge duct can be, for example, an open pipe connection. In a preferred embodiment, the discharge duct is free of internal components such as flaps or valves. Preferably, no fan is also installed in the discharge duct.

[0025] In a preferred embodiment, the control housing is further provided without an air inlet. Apart from the exhaust, there is therefore no possibility of gas exchange with the environment. Consequently, targeted ventilation of the control housing is neither possible nor intended in this system.

[0026] In a preferred embodiment, the at least one heat exchanger is connected to the at least one hydraulic circuit via a connecting line running within the control housing. A gas separator is attached to this connecting line and is designed for the direct degassing of the fluid circulating in the hydraulic circuit into the control housing. This measure enables direct degassing by means of the gas separator without an additional degassing line. The gas separator is a conventional gas separator or microbubble separator known per se.

[0027] Basically, there are different types of leaks. For example, continuous, minor leaks in heat exchangers can lead to refrigerant accumulating in the connected hydraulic circuits. These circuits typically contain devices for separating gas components from the liquid carrier medium, so-called gas separators.

[0028] In many systems, a so-called buffer storage tank is often integrated into the hydraulic circuit. Such a buffer storage tank is, for example, equipped with a gas separator so that separated gas can escape, or the buffer storage tank itself is designed as a gas separator. The buffer storage tank is preferably designed as described in EP 4 047 275 A1. Therefore, in the event of refrigerant leakage into the hydraulic circuit, refrigerant is discharged via the buffer storage tank.

[0029] The hydraulic circuit typically includes at least one safety valve, which opens to relieve pressure, particularly in the event of overpressure, allowing the refrigerant flowing in the hydraulic circuit to escape. The safety valve opens specifically in the event of a refrigerant leak, when refrigerant enters the hydraulic circuit. Such a leak leads, for example, to a significant increase in the flow rate and / or system pressure within the hydraulic circuit.

[0030] Preferably, a vent line is connected to a respective device such as a gas separator, buffer tank, or safety valve and is used for the controlled removal of gas components present in the hydraulic circuit's fluid, which may also include refrigerant components. In particular, these gas components are at least indirectly routed to the outside via the vent line.

[0031] According to one variant, such a vent line is routed into the control room. This directs the gas components present in the hydraulic circuit's fluid into the control housing, where they are detected, for example, by a leak detection device. This thus enables not only direct monitoring of the refrigeration circuit within the control housing, but also comprehensive monitoring of the entire system, including the hydraulic circuits.

[0032] In an alternative, preferred embodiment, the vent line of the safety valve and / or the buffer tank preferably terminates outside the control housing. The vent line preferably opens, at least indirectly, to the outside. This prevents the control housing from being flooded with refrigerant, compared to the previously described embodiment where the vent line opens into the control housing. For example, the vent line is routed directly to the outside, ensuring reliable venting of the gaseous components.

[0033] In an air / water refrigerant system with the previously described preferred arrangement of the air / refrigerant heat exchanger in the air duct, the respective vent line preferably terminates in this air duct. This ensures that, in the event of a refrigerant leak, the refrigerant is directed through the air duct and from there to the outside.

[0034] In a preferred embodiment, a shut-off device, in particular a shut-off or sealing valve, is arranged in the hydraulic circuit. This device shuts off the hydraulic circuit in the event of a pressure increase and / or an increase in the volume flow rate above a predetermined limit, specifically preventing it from being in flow communication with the at least one heat exchanger. The shut-off device therefore closes off a corresponding hydraulic line as soon as the pressure and / or the volume flow rate exceeds the defined limit, so that the fluid medium flowing in the hydraulic line during normal operation (e.g., water in a consumer circuit; brine in a brine circuit) no longer circulates. This initially prevents further refrigerant from entering the hydraulic circuit, for example, via a leak in the heat exchanger.

[0035] Essentially, a heat source / heat sink section of the hydraulic circuit is separated from a refrigeration circuit section and the heat exchanger located there. Preferably, in addition to the shut-off device, a check valve, specifically a non-return valve or a non-return device, is also provided.

[0036] In the refrigeration circuit section, a safety valve and / or a gas separator is preferably also installed. Any refrigerant present can then be reliably vented via these devices. For this purpose, the measures described above are preferably used, such as arranging the gas separators within the control housing and / or venting via the vent line.

[0037] The locking device is preferably a passive locking element that automatically shuts off the hydraulic circuit when a limit value is exceeded and preferably also releases it again when the limit value is undershot. Specifically, the locking device is a spring-loaded sealing element such as a sealing valve or sealing flap. The (defined) spring force holds the sealing element open up to a defined limit value for pressure or flow rate. Preferably, the spring force is adjustable. When the limit value is exceeded, the sealing element is forced into a closed position, which it preferably releases automatically when the limit value is again undershot.

[0038] This design is based on the consideration that in the event of refrigerant entering the hydraulic circuit, this leads to a displacement of the carrier medium and thus to a higher flow velocity / higher pressure.

[0039] The previously described embodiment with the locking device and the automatic hydraulic decoupling of a portion of the hydraulic circuit, particularly in combination with the arrangement of the safety valve in the refrigeration circuit section, is also considered an independent invention, regardless of the configuration with the sealed control housing and the drain. The filing of a divisional application for this aspect remains reserved, i.e., for a refrigerant system with the features of claim 1 without the features of the sealed control housing and the drain, but with the features of claim 7. In preferred embodiments, such an independent claim is followed by dependent claim 8 and / or the previously described specific arrangement of the safety valve with a vent line to the outside.Furthermore, the dependent claims 2-6 and 9-14 are analogous to such a new claim, in particular also in conjunction with the further advantageous additions and extensions as listed in the description.

[0040] In a preferred embodiment, the cable has an inner section and an outer section. The inner section is connected to the control housing and leads to an interface on the system housing. The outer section is in turn connected to the inner section at this interface; that is, the two sections of the cable can be coupled together.

[0041] This preferably also applies to other components connected to the refrigeration circuit. This includes, for example, at least one hydraulic circuit. At least one connecting line is provided for this circuit, which is connected on one side to the control housing, specifically to one of the heat exchangers, and on the other side also leads to the interface on the system housing. At this interface, the hydraulic circuit, or at least parts of it that are not located inside the system housing, can therefore be reversibly connected, for example via appropriate screw connections.

[0042] In case a second hydraulic circuit is provided, an additional connecting line is routed between the control housing and the interface.

[0043] Preferably, coupling elements are also attached to the control housing for the reversible connection of the control housing and the components located therein, in particular with the inner section of the line and the at least one connecting line. These connecting elements, such as the inner section or the at least one connecting line leading to the interface on the system housing, are therefore designed as connecting pieces between two interfaces: on the one hand, an interface to the control housing, and on the other hand, an interface to the outside outside the system housing.

[0044] In addition, coupling elements for reversibly connecting the components arranged inside the control housing to the other components outside the control housing are preferably provided externally. This includes, for example, an electrical coupling element through which, for instance, a power supply or control of at least one of the components, such as the compressor, is provided. The coupling element is, in particular, a connector.

[0045] This measure allows for easy installation of the entire control housing within the system. Specifically, it is an interchangeable control housing, meaning that it can be removed from the system housing as a single unit, together with the components it contains. Preferably, the control housing is mounted on rails or a support, and in particular, it is vibration-isolated from the rest of the system housing.

[0046] Preferably, the control housing is divided and can be opened. This allows access to the internal components. The at least two, and preferably exactly two, housing halves have a suitable sealing arrangement at their dividing point, for example, a sealing element or a suitable wall design, for example, according to the tongue-and-groove principle.

[0047] The system housing is preferably designed as a modular cabinet with several housing sections, each containing different functional modules. The housing sections for the different functional modules are, for example, designed as independent housing modules. The control housing, in turn, is preferably located within a refrigerant module, which is one of the functional modules and is located in a closed housing section, preferably in its own module housing. The refrigerant module, together with at least one other functional module and its further housing section / module housing, forms the modular cabinet. Preferably, a storage module with a domestic hot water storage tank is provided as an additional functional module. Preferably, the refrigerant module and the additional functional module are arranged one above the other.

[0048] The refrigerant system described here is specifically designed as a heat pump system for buildings, i.e., for providing heat to a building. The heat pump system is particularly suitable for heating residential buildings, such as single-family or multi-family homes. The heat pump system has a maximum heating capacity of, for example, only 10 kW or only 20 kW.

[0049] In addition to the measures described above, which enable the simplest and most practical installation of such a refrigerant system with a high degree of safety against critical refrigerant accumulation in the event of a refrigerant leak, further specific measures are described below that are used to improve the control and monitoring of the system with regard to refrigerant leaks: A fan is arranged in the duct. This fan makes it possible to actively and selectively vent refrigerant from the control housing. Ideally, the passive and permanently open flow connection via the duct is maintained. For this purpose, the fan is preferably designed and configured in such a way that it does not, or at least not completely, close the duct, so that an open flow connection exists via the fan even when it is not actively operating.In particular, the design allows the fan to rotate freely even when switched off. This ensures that in the event of a leak, i.e., when increased pressure occurs in the control housing, the gas can still escape passively via the vent. The increased pressure in the control housing allows the gas to escape through the vent and also past the fan, which only presents a certain flow resistance, but not a complete flow barrier.

[0050] At the same time, the fan offers the possibility to ensure targeted and active removal of the refrigerant when needed and is also controlled accordingly when required.

[0051] Furthermore, a device for detecting leaks in the refrigeration circuit is provided, which includes an evaluation unit. This device serves, for example, for the indirect or direct detection of a leak. Preferably, the evaluation unit is used to determine the extent of the leakage and thus the degree of refrigerant loss and therefore the leak rate. Furthermore, the evaluation unit is used to initiate countermeasures, preferably different countermeasures depending on the extent of the refrigerant loss.

[0052] The evaluation unit is generally designed to monitor the refrigerant system for refrigerant leaks and to initiate appropriate safety measures if necessary. The evaluation unit is therefore configured to perform the control and monitoring measures described below.

[0053] Specifically, depending on the detection of a leak, for example, based on the measurement signal of a leak detector or a gas sensor in the control volume, or based on the evaluation of fan characteristics, a safety measure is initiated. This might include targeted control of the fan, such as switching it on or increasing its speed. Depending on the extent of the leak, a safety shutdown of the refrigerant system may also be performed. Therefore, depending on the identified leak rate, various measures are taken, ranging from warning messages and / or fan activation to an automatic safety shutdown.

[0054] According to the invention, the evaluation unit is configured to infer a leakage within the refrigeration circuit based on at least one characteristic value of the fan. In this embodiment, the fan, together with suitable sensors, therefore forms the leak detection device.

[0055] This is based on the consideration that in the event of a leak, the flow and pressure conditions within the discharge and within the control housing change characteristically, and these changes also lead to characteristic changes in the operating parameters of the fan, which are evaluated.

[0056] Preferably, at least one of the following parameters is used and evaluated: According to a first embodiment, the fan characteristic curve or at least a current operating point of the fan is evaluated. In this context, the fan characteristic curve is understood to be the course of the differential pressure between a suction side and a discharge side of the fan with respect to the delivered volume flow rate or the fan speed. The operating point is a specific point on the fan characteristic curve, i.e., for example, a defined relationship between a given volume flow rate and the differential pressure.

[0057] This analysis is based on the premise that, due to the hermetic seal of the control housing, the fan characteristic curve varies in steepness depending on the presence of a leak. If there is no leak and therefore no gas escapes into the control volume, the fan characteristic curve is very steep. Conversely, the fan characteristic curve becomes increasingly flatter with an increasing leak rate. Therefore, it is possible to reliably determine whether a leak is present from the current fan characteristic curve or the current operating point. Preferably, the leak rate is also derived from the fan characteristic curve and the operating point in order to initiate appropriate countermeasures.

[0058] Alternatively, or additionally, the fan speed is evaluated, particularly when the fan is not actively operating. This is based on the premise that a refrigerant leak leads to an increase in pressure within the control housing, causing the gas to flow out through the vent and thus essentially driving the fan. An increase in speed is therefore an indicator of a leak, specifically an increase in the leak rate. This, in turn, allows conclusions to be drawn about the leak rate.

[0059] Other parameters of the fan that are evaluated include, alternatively or additionally, its electrical current or power consumption as well as vibration values.

[0060] It is generally preferred to infer a measure of leakage and thus the leakage rate from the determined characteristic values ​​of the fan.

[0061] Alternatively or additionally, a gas sensor, specifically a CO₂ sensor or alternatively an N₂ or O₂ sensor, is provided as a device for leak detection. A gas sensor that directly detects the refrigerant gas can also be used. This gas sensor serves to directly, or at least very directly, determine whether refrigerant is present in the control volume and, in particular, what its concentration is. The use of a CO₂ sensor, or a sensor that measures another component (O₂, N₂) of the atmosphere, is based on the consideration that in the event of a refrigerant leak, the natural CO₂ content (O₂, N₂ content) is reduced. This reduction then indicates a leak.

[0062] As an alternative or supplement to a gas sensor, a pressure sensor is provided which measures an increase in pressure inside the control housing as a result of a leak.

[0063] Active monitoring is particularly advantageous overall for initiating appropriate countermeasures, i.e., for controlling the system. Since non-critical components can also outgas during system operation in the hydraulic circuits, meaning they do not lead to critical accumulations of, for example, explosive mixtures, this variant, with its vent line leading into the control housing, is preferably combined with an additional monitoring measure, in particular monitoring by means of a gas sensor.

[0064] In a preferred embodiment, a leak detector is arranged on the at least one connected hydraulic circuit and is connected to the evaluation unit. In this case, the evaluation unit therefore receives an (electrical) sensor signal and can take this into account for assessing the hazard potential and initiating safety measures.

[0065] In one embodiment, a volume flow sensor and / or a pressure sensor are used as leak detectors. The evaluation unit then analyzes the sensor signal from the leak detector to determine the presence of refrigerant in the carrier medium. Specifically, characteristic signal fluctuations are evaluated as indicators of refrigerant presence.

[0066] The volumetric flow sensor is designed, for example, as an ultrasonic sensor, but can also be a vane sensor or based on the principle of the Karman vortex street. The evaluation of these sensor signals is generally based on the assumption that if refrigerant is present in the liquid carrier medium, the refrigerant is in gaseous form, meaning that gas bubbles are contained within the carrier medium. Such gas bubbles lead to characteristic signal variations in both the volumetric flow sensor and the pressure sensor, which are evaluated by the processing unit and used to assess the level of risk.

[0067] The problem is further solved according to the invention by a refrigerant module for the refrigerant system described above. The refrigerant module comprises the control housing and the other components connected to the control housing, namely, in particular, the inner section of the discharge, the at least one connecting line for the hydraulic circuit, and preferably further hydraulic or electrical components, such as a circulation pump, valves, a control unit, an operating terminal, etc. Preferably, components of the at least one hydraulic circuit are already integrated into the refrigerant module. The refrigerant module preferably also has its own module housing, which therefore has the interfaces to which the at least one hydraulic circuit, or at least some of its components, especially the consumer, can be connected via the interface.

[0068] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. These show simplified representations of: FIG 1 shows a refrigerant system designed as a heat pump system with a system cabinet as the system housing before final installation and before the actual placement in an installation room; FIG 2 shows a refrigerant module with a control housing, which is shown in the illustration of the Figure 2 FIG 3 is a highly simplified representation of a residential building to illustrate the installation of the system housing with a downpipe, FIG 4 a circuit diagram for an air / water heat pump system, FIG 5 a circuit diagram for a brine / water heat pump system, FIG 6 a representation of different fan characteristic curves, FIG 7 a representation of a signal profile of a volume flow sensor, and FIG 8 a simplified representation of the profile of a sensor signal of a pressure sensor.

[0069] In the figures, parts with the same effect are marked with the same reference symbols.

[0070] One in the Figure 1 The refrigerant system designed as a heat pump system 2 has a system housing 4 designed as a system cabinet. The heat pump system 2 has a modular design and, in the exemplary embodiment, comprises two modules, namely a refrigeration module 6 and a storage module 8. Each of the modules 6, 8 is arranged in its own housing section, in particular in its own module housing. The two module housings are stacked on top of each other and form the system housing 4. A storage tank, specifically a domestic hot water storage tank 10, is arranged in the storage module 8. The refrigeration module 6, as it is again in standalone configuration in Figure 2 As shown, a refrigeration circuit 12 is arranged inside a control housing 14. This housing has two housing halves. In the Figure 2The control housing 14 is open, and only one of the housing halves is shown. Additionally, the refrigeration module contains 6 further components, which will be explained below.

[0071] The control housing 14 is a hermetically sealed housing into which no ambient air can enter. In the exemplary embodiment, the control housing 14 is a two-part housing which can, in principle, be opened, for example, for maintenance purposes.

[0072] A line 16, specifically an internal section 16A, is connected to the control housing 14 and is preferably reversibly detachable. Internal section 16A generally refers to a section of the line 16 running inside the system housing 4. In some embodiments (compare, for example, the embodiment described below) Figure 4The inner section 16A forms the entire drain. The drain 16 is preferably connected to the control housing 14 in a lower section, specifically in the lower third. It generally provides a flow connection to the inner volume of the control housing 14. In the event of a refrigerant leak, the drain 16 serves to drain the refrigerant.

[0073] In the exemplary embodiment, the control housing 14 is arranged within its own module housing 18. It is preferably arranged on its own support 19 and, via this, on a base of the module housing 18, and is particularly vibration-isolated. The control housing 14 is preferably made of a plastic, specifically a foamed plastic.

[0074] Preferably, at least one connecting line 20 is attached to the control housing 14, in particular in a reversibly detachable manner. The connecting line 20 is connected to a heat exchanger, specifically a condenser, located in the control housing 14. If two hydraulic circuits are connected to the refrigeration circuit 12, two connecting lines 20 are provided. The control housing also preferably has an electrical connection, specifically via a detachable plug connection, through which control signals or an electrical power supply for the components located within the control housing 14 are transmitted.

[0075] Both the connecting line 20 and the inner section 16A are routed to an interface 22. In the exemplary embodiment, the connecting line 20 and the inner section 16A are arranged on the rear of the control housing 14 and are routed from there to the interface 22. In the exemplary embodiment, this interface is formed on the upper side of the system housing 4 and, in particular, the module housing 18. Hydraulic couplings, in particular, for connection to other components of hydraulic circuits 64, 66 (see Figure 1) can be connected via the interface 22. Figures 4 , 5 ) provided. Furthermore, interface 22 also provides a connection via which the internal component 16A can be connected.

[0076] Within the refrigeration module 6, 14 additional hydraulic and electrical components are arranged outside the control housing. These include, for example, pumps, pipe elements, valves if required, and, with regard to the electrical components, in particular a control unit for controlling the heat pump system. Furthermore, a control element for inputting and operating the control unit is preferably provided.

[0077] Based on the Figure 3 Figure 1 shows a preferred, exemplary configuration of such a heat pump system 2 within a building 24. The heat pump system 2, specifically the system housing 4 with the components located therein, is arranged within an installation room 26. The exhaust 16 is routed to an external area 28, in this case the environment outside the building 24.

[0078] The Figures 4 and 5 show different variants of a heat pump system, whereby the Figure 4For example, an air / water heat pump system 2 and the Figure 5 This represents a brine / water heat pump system 2. The [unclear text] in the Figures 1 to 5 The reference symbols shown denote the following components: 2 Heat pump system 4 System housing 6 Refrigeration module 8 Storage module 10 Domestic hot water storage tank 12 Refrigeration circuit (if applicable)(reversible) 14 Control housing (control volume) 16 Discharge (outlet duct) 16A Inner section of the discharge 16B Outer section of the discharge 18 Module housing 19 Support 20 Connecting line 22 Interface 24 Building 28 Exterior 30 Fan / exhaust fan (optional) 32 Sensors Fan characteristics 34 Gas sensor 36 Vent line 38 Volume flow sensor 40 Gas separator / microbubble separator 42 Check valve ) 44 Pressure sensor 46 Circulating pump 48 Safety valve 50 Expansion vessel 52 Consumer (heat consumer heating / cooling consumer) 54 Heat source / heat sink 58 Buffer tank especially as part of a double differential pressureless distributor 60 Air / refrigerant heat exchanger with primary fan 62 Air duct 64 Consumer circuit 66 Brine circuit 68 Condenser 70 Evaporator 72 Coupling element 74 Control unit 76 Evaluation unit 78 Locking device 84 Connection lines 86 Channel section .

[0079] In the exemplary embodiments, the refrigeration circuit 12 comprises a compressor, the condenser 68, an expansion valve, and the evaporator 70. The components are piped together, and a refrigerant circulates in the refrigeration circuit 12. Several of the components, in the exemplary embodiment of the Figure 5 all and in the exemplary embodiment of the Figure 4 All except the evaporator 70 are arranged within the control housing 14, which leads to the installation space 26 of the system housing 4 ( Figure 3 ) is sealed gas-tight. It is only connected to the outside 28 via the permanently open drain 16.

[0080] Both in the case of the brine / water heat pump system 2 according to Figure 5 as well as in the case of the air / water heat pump system 2 according to Figure 4A consumer circuit 64 with a consumer 52 is connected to one of the two heat exchangers on the refrigeration circuit 12, namely the condenser 68. The buffer storage tank 58 is also integrated into the consumer circuit 64. Such a buffer storage tank 58 is generally known and is typically arranged in series between refrigeration circuit 12 and consumer 52. During operation, it is completely or almost completely filled with the heat transfer medium circulating in the consumer circuit 64, and this medium also flows through it. Typically, no heat exchangers are arranged in the buffer storage tank 58. Such buffer storage tanks 58 generally have a volume that depends on the application and the system capacity. The volume is typically at least 50 dm³, or at least 100 dm³, or even several hundred dm³, and sometimes even over 1000 dm³.Typically, the buffer storage tank 58 has a volume, for example, in the range of 10-50 dm³ / kW and, in particular, in the range of 20-40 dm³ / kW of the maximum heating output of the heat pump system 2 (maximum nominal output of the heat pump system 2). The buffer storage tank 58 is regularly a cylindrical pressure vessel with a typically domed bottom and lid.

[0081] Furthermore, in the exemplary embodiments of the Figures 4 and 5 In the consumer circuit 64, a passive shut-off device 78, specifically in the form of a flap, is integrated. In particular, this is arranged directly on the outlet side (cooling water / hot water) of the heat exchanger 68 (condenser). In the embodiment according to the Figure 5Preferably, a similar locking device 78 is also provided in the brine circuit 66. This is also arranged on the outlet side (outlet to the heat source / heat sink) of the other heat exchanger 70 (evaporator).

[0082] In the exemplary embodiments, the shut-off device 78 is effective in the direction of flow of the respective carrier medium in the respective hydraulic circuit 64, 66 and closes automatically when a predetermined limit value is exceeded, for example, a predetermined flow velocity, and / or a predetermined volume flow rate and / or a predetermined pressure of the carrier medium. In the exemplary embodiment, the shut-off device 78 in the consumer circuit 64 is arranged between the control housing 14 and the buffer storage tank 58 or the consumer 52.

[0083] Furthermore, a check valve 42 is arranged in the respective hydraulic circuit 64, 66 in the flow direction downstream of the heat sink (e.g., consumer 52) or downstream of the heat source (e.g., 54). The shut-off device 78 and the check valve 42 allow a heat sink / heat source side section of the respective hydraulic circuit 64, 66 to be hydraulically isolated from a refrigeration circuit side section of the respective hydraulic circuit 64, 66. This occurs automatically when the shut-off device 78 closes upon exceeding the limit value.

[0084] In a preferred embodiment, not shown in detail here, the locking device 78 is connected to the hydraulic line in the area of ​​the check valve 42 via a fluid line, e.g., a capillary tube, specifically on the side of the check valve 42 facing away from the refrigeration circuit and thus the heat exchanger. At this point, the pressure level of the fluid in the hydraulic circuit acts. The locking device 78 is preferably subjected to this pressure. Specifically, this pressure acts on the locking device 78 in the opening direction.

[0085] In the exemplary embodiment of the Figure 5Figure 2, which shows a brine / water heat pump system 2, has a second hydraulic circuit, namely a brine circuit 66, connected to the other heat exchanger, namely the evaporator 70. Hydraulic circuits 64 and 66 are each connected to the control housing 14 by means of a coupling element 72, so that corresponding piping can be connected to the control housing 14. As can also be seen, some essential components of the hydraulic circuits 64 and 66 are already connected within the system housing 4. For example, part of the piping is arranged within the system housing 4; specifically, the connecting line 20, which leads to the interface 22, is located within the system housing 4. In the illustrated embodiments, there is also external piping, the (optional) buffer storage tank 58, and at least one consumer 52 outside the system housing 4, as well as, in the variant according to Figure 4, the following: Figure 5The heat source / heat sink 54 is connected, possibly with additional components such as valves, pumps, etc. In the variant according to... Figure 4 Four channel sections 86, namely an intake line and an exhaust line, are connected to air duct 62 on the system housing.

[0086] During the Figure 4 In the depicted air / water heat pump system 2, an air duct 62 is provided, within which a unit 60 consisting of an air / refrigerant heat exchanger (evaporator 70) with a fan is arranged. The air duct 62 is connected via interfaces 22 to the intake duct for outside air and to the exhaust duct for exhaust air, which typically pass through a building wall and extend to the outside 28. It should be emphasized that the air duct 62 runs within the system housing 4 and is connected via the interfaces 22 to the duct sections 86 leading to the outside 28.

[0087] Within the plant housing 4, there is also a [device / component] shown in the diagrams of the Figures 4 and 5 A simplified control unit 74 is arranged, which controls the operation of the heat pump system 2. In the exemplary embodiment, this unit also includes an evaluation unit 76, which is designed to monitor and control the system with regard to refrigerant leakage and to initiate safety measures. For this purpose, the heat pump system 2 has one or more devices for detecting a refrigerant leakage.

[0088] In general, it is provided that the line 16, more precisely the inner part 16A, is connected to the control housing 14, preferably via a coupling element 72.

[0089] Within the control housing 14, connecting lines 84 run, each of which is connected on one side to at least one heat exchanger (condenser 68 and, in the exemplary embodiment, the Figure 5(also evaporator 70) and lead to the respective coupling element 72, via which the connection to the connecting line 20 is made. The connecting lines 84 are therefore each part of the respective hydraulic circuit (consumer circuit 64 / brine circuit 66). Inside the module housing 14, a gas separator 40, for example a microbubble separator, is now attached to each hydraulic circuit, specifically to each connecting line 84. The particular advantage of this arrangement is that, if necessary, the carrier medium of the hydraulic circuit 64, 66 can be degassed directly into the interior of the control housing 14 via the gas separator 40, and the gas can escape into the exterior 28 via the vent 16.

[0090] In both variants, a preferred embodiment provides that no other degassing or venting lines 36 terminate in the control housing 14. Further venting lines 36, which are connected, for example, to the buffer storage tank 58 or to a safety valve 48, bypass the control housing 14 and lead at least indirectly to the outside 28.

[0091] In the exemplary embodiment of the Figure 4 A total of two vent lines 36, one from the buffer storage tank 58 and one from a safety valve 48, lead into the air duct 62 and open there. In the version of the Figure 4 The safety valve 48 with the connected vent line 36 is arranged in the refrigeration circuit-side section of the consumer circuit 64.

[0092] If, as described above, for example in the event of a refrigerant leak, the consumer-side section is hydraulically isolated by closing the shut-off device 78, gas and possibly also part of the carrier medium can escape via the safety valve 48 and the connected vent line 36.

[0093] Such a safety valve 48 with connected vent line 36 is, preferably also (deviating from the illustration according to Figure 5 ) in the version of the Figure 5 The vent line 36 is routed to the exterior area 28. The vent line 36 connected to the buffer storage tank 58 is also routed to the exterior area 28. In the exemplary embodiment, it is connected to the drain 16.

[0094] In general – regardless of the specific design variant – in a preferred embodiment, one or more such vent lines 36 are connected to the drain 16. This means that only one penetration through the building wall is required.

[0095] In an (optional) version with a fan 30, a fan 30 is arranged within the inner section 16A. A sensor 32 is assigned to this fan for monitoring and evaluating the characteristic values ​​of the fan 30, as well as its fan characteristics and / or the fan curve. The fan 30 and the sensor 32 are located in the Figure 5 This is shown as an example. Similarly, the following applies to the implementation variant of... Figure 4A fan 30 of this type is arranged in the downpipe 16, more precisely in the inner section 16A. In alternative embodiments, such a fan is omitted, and only an open pipe connection is provided as the downpipe 16 without any internal components.

[0096] Specifically, the sensor system 32 includes pressure sensors that detect the suction-side pressure and the pressure on the discharge side, or at least the differential pressure between the suction and discharge sides of the fan 30. Furthermore, the sensor system 32 can, if required, detect the rotational speed of the fan 30, its power consumption, or its electrical current consumption. A vibration sensor can also be included to detect vibrations. Based on the fan characteristics, specifically the fan curve or operating points, a conclusion can then be drawn, for example, regarding a refrigerant leak.

[0097] Furthermore, a gas sensor 34, specifically a CO₂ sensor, is (optionally) arranged inside the control housing 14. This sensor measures, at least indirectly, the refrigerant concentration inside the control housing 14, for example, by measuring the decrease in the CO₂ content. In a preferred embodiment, however, such a gas sensor 34 is omitted.

[0098] Furthermore, flow sensors 38 and pressure sensors 44 are shown as examples, which can be used to detect whether refrigerant is present in the hydraulic circuits 64 and 66. The sensor signals from the respective flow sensor 38 and / or pressure sensor 44 are transmitted to the evaluation unit 76 and evaluated there.

[0099] The evaluation of the fan characteristics is based on the Figure 6This illustrates a qualitative progression of the operating points of fan 30 as a function of the leakage rate: It includes various fan characteristic curves A, B, and C, where the differential pressure Δp (head h) is plotted against the volume flow rate V / h. Characteristic curve A characterizes a state in which there is no leakage and the refrigerant system is sealed against the environment. In this state, the characteristic curve is very steep. Characteristic curve B characterizes a state with a low leakage rate, and characteristic curve C characterizes a state with a high leakage rate. The characteristic curves become progressively flatter, so that each curve is characteristic not only of a leakage but also of the leakage rate.

[0100] For the evaluation, it is sufficient to record the respective operating points 1, 2, and 3 at a given current volume flow rate. This can be derived from the current speed of fan 30. This means that, based on the current speed and knowing the differential pressure Δp, an operating point can be uniquely assigned, and from this, a leakage rate can be deduced.

[0101] Alternatively or additionally to this evaluation, the speed of fan 30 is used, especially with an unchanged speed setting and particularly in the case of large leaks. It is possible that fan 30 is switched off (speed equal to zero) or is only rotating at a low speed, thus delivering only a small volume flow rate (V / h). In the event of a leak, especially a large leak or a sudden leak, for example, due to a pipe rupture, significant pressure increases typically occur. The leakage mass flow rate, i.e., the leakage rate (mass of refrigerant per unit time) of the escaping refrigerant, can reach up to 100 g / s. This pressure increase causes the speed to increase automatically. Such a change in speed is evaluated, and the leakage rate is inferred from it.

[0102] Finally, as an alternative or further supplement, a change in electrical current / power consumption is evaluated, specifically with an unchanged speed setting. Due to a pressure increase in the event of a leak, the required power changes, and thus the electrical current / power consumption changes, even with the speed setting otherwise remaining the same. Specifically, the electrical current consumption decreases because the fan is driven automatically.

[0103] The course of a sensor signal S of the volume flow sensor 38 (volume flow signal) over time t is determined based on the Figure 7 illustrated. Figure 7This shows the qualitative course of the sensor signal S over time t as a function of the presence of gas bubbles in the carrier medium. If gas bubbles occur within the hydraulic circuit 64, 66, this leads to a characteristic signal course. Specifically, the normally constant signal course S, which is present when no gas bubbles are present in the carrier medium, changes, and an unstable zone with strong signal fluctuations occurs when gas bubbles are present in the carrier medium. In the Figure 7A tolerance range is also shown, depicted with a dashed line, which is clearly exceeded in the case of gas bubbles. These signal fluctuations can then be used to infer the proportion of gas bubbles within the carrier medium. Specifically, when combined with the gas sensor 34, a statement can then be made about the refrigerant content within the hydraulic circuits 64 and 66. However, it is preferable to forego an additional gas sensor 34 for detecting escaping gas, especially refrigerant. This has the advantage of saving the costs associated with, for example, refrigerant-sensitive sensors.

[0104] The same applies to the evaluation of the sensor signal S of the pressure sensor 44, which is exemplified in the Figure 8 is illustrated. Figure 8This shows a qualitative progression of an operating point in hydraulic circuit 64, 66 over time t. Here, too, gas components within the carrier medium lead to characteristic signal fluctuations, which in turn exceed a tolerance threshold (shown as a dashed line) of an otherwise usually largely constant signal S. These evaluations are also combined, for example, with an evaluation of the signal from gas sensor 34.

[0105] The invention is not limited to the embodiment described above. Rather, other variants of the invention can also be derived by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the embodiment can also be combined with one another in other ways without departing from the subject matter of the invention.

Claims

1. Refrigerant system with - a refrigerating circuit (12), which has two heat exchangers, to be specific an evaporator (70) and a condenser (68), and also a compressor as well as an expansion valve and in which a refrigerant circulates during operation, wherein at least one hydraulic circuit (64, 66), in which a carrier medium is circulated during operation, is connected to the refrigerating circuit (12) in the installed state, - a system housing (4), which in the installed state is installed in an installation room (26) and in which at least a number of components of the refrigerating circuit (12) and further components, such as hydraulic or electrical components, are arranged, wherein a sealed control housing (14), in which the components comprising the compressor, the expansion valve and at least one of the heat exchangers of the refrigerating circuit (12) are arranged, is arranged inside the system housing (4), and wherein a discharge line (16), which is intended for discharging gas from the control housing (14) and is in flow connection with an external area (28) outside the installation room (26), is connected to the control housing (14), wherein a fan (30) is arranged in the discharge line (16), characterized in that a device for detecting a leakage in the refrigerating circuit (12) is provided and comprises an evaluation unit (76), which is designed in such a way that it infers a leakage within the refrigerating circuit (12) on the basis of at least one characteristic value of the fan (30).

2. Refrigerant system according to the preceding claim, characterized in that one of the two heat exchangers is designed as an air / refrigerant heat exchanger and is arranged in an air duct (62), wherein the discharge line (16) opens out into the air duct (62), wherein the air duct (62) runs in particular inside the system housing (4) and is preferably connected via interfaces (22) to duct sections (86) leading into the external area (28).

3. Refrigerant system according to the preceding claim, characterized in that the discharge line (16) provides a permanently open flow connection to the external area (28), so that escaping refrigerant can automatically flow into the external area (28), wherein the open flow connection is preferably free from internal fittings.

4. Refrigerant system according to one of the preceding claims, characterized in that the control housing (14) has no supply-air opening.

5. Refrigerant system according to one of the preceding claims, characterized in that the at least one heat exchanger is connected via a connection line (84), running inside the control housing (14), to the at least one hydraulic circuit (64, 66), wherein a gas separator (40), which is intended for the direct degassing of a carrier medium conducted in the hydraulic circuit (64, 66) into the control housing (14), is attached to the connection line (84).

6. Refrigerant system according to one of the preceding claims, characterized in that on the hydraulic circuit (64, 66) outside the control housing (14) a device, to be specific a safety valve (48) and / or a buffer storage tank (58), is respectively connected to a venting line (36), wherein the venting line (36) opens out at least indirectly into the external area (28) and, in the case of an air / water refrigerant system (2), opens out into an air duct (62), in which an air / refrigerant heat exchanger is arranged.

7. Refrigerant system according to one of the preceding claims, characterized in that arranged in the hydraulic circuit (64, 66) is a shut-off device (78), in particular a shut-off or sealing valve, which in the event of a pressure increase and / or an increase in the volumetric flow beyond a limit value shuts off the hydraulic circuit (64, 66), in particular in such a way that it is no longer in flow connection with the at least one heat exchanger, wherein preferably a heat-sink-side or heat-source-side subregion of the hydraulic circuit (64, 66) is hydraulically disconnected from a refrigerating-circuit-side subregion of the hydraulic circuit (64, 66).

8. Refrigerant system according to the preceding claim, characterized in that the shut-off device (78) is a passive shut-off element which automatically shuts off the hydraulic circuit (64, 66) when the limit value is exceeded and preferably also releases it again when the limit value is no longer exceeded.

9. Refrigerant system according to one of the preceding claims, characterized in that an internal piece (16A) of the discharge line (16) and at least one connecting line (20) for the at least one hydraulic circuit (64, 66) are connected to the control housing (14) and the internal piece (16A) and the at least one connecting line are led to a respective interface (22) of the system housing (4), via which an external piece (16B) of the discharge line (16) and at least parts of the at least one hydraulic circuit (64, 66) can be coupled, wherein, in a preferred configuration, coupling elements (72) intended for connecting, in particular reversibly, to the internal piece (16A) and / or to the at least one connecting line (20), and also preferably to at least one of the further components arranged in the system housing (4), are arranged on the control housing (14).

10. Refrigerant system according to one of the preceding claims, characterized in that the system housing (4) is designed in the manner of a module cabinet and the control housing (14) is arranged inside a refrigerant module (6), wherein preferably a storage module (8) with a service-water storage tank (10) is additionally provided and the refrigerant module (6) and the storage module (8) are in particular arranged one on top of the other.

11. Refrigerant system according to one of the preceding claims, characterized in that at least one of the following characteristic values of the fan (30) is evaluated: - fan characteristic curve or current operating point, - rotational speed, in particular in a state when the fan is not actively operated, - electrical current or power consumption, - vibration.

12. Refrigerant system according to the preceding claim, characterized in that a leakage rate is derived from the characteristic value.

13. Refrigerant system according to one of the preceding claims, characterized in that a device for detecting a leakage in the refrigerating circuit (12) is provided and a gas sensor (34), in particular a CO2 sensor, or a pressure sensor is arranged in the control housing (14) as the device for detecting the leakage.