Outdoor unit with safety vent

Abstract

Method and apparatus for ventilating an outdoor unit of a heat transfer system which is operated with a flammable refrigerant, the outdoor unit comprising a housing with a refrigeration circuit with a flammable refrigerant, at least one fan in an air duct with at least one heat exchanger, in which the fan runs continuously and conveys air and is designed to be non-stop, thus making the safety zone unnecessary.

Description

[0001] The invention relates to an outdoor unit for a heat transfer system, enabling a variety of uses, and a safety ventilation system that prevents the formation of a flammable refrigerant-air mixture in the immediate vicinity of an outdoor heat pump. As is known, heat pumps are used to heat and / or cool media, thereby heating and / or cooling houses or other buildings. Using a refrigerant in a refrigeration cycle, environmental energy, e.g., geothermal energy or ambient air, or even waste heat from the heat source, is extracted, raised to a higher and thus usable temperature level, and supplied to the heat sink, for example, the heating system. The system uses at least a portion of a compression refrigeration cycle with a flammable refrigerant and has a safety system that prevents the formation of a flammable refrigerant-air mixture.

[0002] The outdoor unit's housing is designed for an optimal balance between openings and the purge / ventilation provided by the fan. Unless the air conditioning or heat pump is operating, requiring the fan to maintain airflow through the heat exchanger located in the outdoor unit, a minimum airflow is ensured. This can be achieved by the existing fan itself, operating at a very low speed, or by other means. During normal operation, a slight negative pressure is created in the compressor compartment. Should a leak occur in this compartment, the system ensures that contaminated air is extracted. Similarly, if a leak occurs in the heat exchanger, the airflow also ensures the reliable removal of the contaminated air.Further suitable measures to ensure airflow even under unfavorable installation, environmental, and climatic conditions are described below. This eliminates the need for a safety distance to adjacent residential buildings and other potential fire hazards.

[0003] A typical heat transfer system for an outdoor unit can provide cooling and heating simultaneously or alternatively. The cooling can be used, for example, for air conditioning, and the heating for heating houses, barns, or greenhouses. In such cases, the outdoor unit operates as a heat pump or air conditioner. For safety reasons, the outdoor unit is continuously and reliably ventilated. The refrigerant has the property of absorbing energy from the heat source as an evaporating liquid at low heat source temperatures. Previously, it was generally non-flammable and non-toxic, but had a considerable global warming potential (GWP). Natural refrigerants have a significantly lower global warming potential, but are flammable and sometimes toxic.

[0004] State-of-the-art heat pumps are installed outdoors using flammable, natural refrigerants or split heat pumps with part of the refrigerant circuit located indoors. For heat pumps installed outdoors as mono or split systems using a flammable refrigerant, such as R290, special safety measures are required in the event of a refrigerant leak, compared to heat pumps based on conventional fluorinated gases (F-gases). It is standard practice to design the electronic components within the unit to be ignition-source-free and to define a protective zone around the heat pump that contains no external ignition sources or building openings.

[0005] CN 201 652 623 U shows an outdoor unit of an air conditioner with two separate housing sections. The first housing section contains a ventilation duct, a fan, and a heat exchanger surrounded by airflow. To prevent the formation of a flammable atmosphere in a cavity of the outdoor unit in the event of a leak of, for example, R290 or R600A, measures are taken. These include a fan with an electronic control device and piping to a housing containing a compressor. This compressor housing is suspended from above and connected to a top cover plate. It is further separated from the fan section by an L-shaped partition plate. At the bottom, it is supported and bolted to a textured base plate. The L-shaped partition plate has numerous slotted openings to the fan duct, as do the front and top covers.The base plate also has openings to allow fresh air to flow in from all sides in the event of a leak, diluting any escaping refrigerant. However, a safety distance to protect buildings and other fire hazards is still essential.

[0006] With the increasing number of equipment replacements in the future, this protected zone can become an obstacle at existing installation sites, often preventing new installations. A well-known countermeasure is to increase the size of the refrigerant outlet. The increased outlet ensures better direct dilution of the refrigerant in the air, preventing the formation of a flammable refrigerant-air mixture. This effect is already utilized when the outdoor unit is wall-mounted, allowing the protected zone to be reduced from a 1 m radius to 0.5 m around the outdoor unit.

[0007] Ignition can be prevented through active dilution. However, a problem arises because the precise location of the anticipated leak is unknown beforehand, making it impossible to know for certain whether the leak will be in gaseous or liquid form. Due to the pressure conditions within the refrigeration circuit, it is usually in gaseous form. This leads to the question of how to safely bridge the ignitable window between an excessively rich and a too-lean refrigerant-air mixture—that is, between the lower and upper ignition limits. Therefore, the potential leak points of liquid refrigerant and those of gaseous refrigerant must be considered separately and addressed with appropriate safety measures.

[0008] For equipment installed outside buildings, or attached to the buildings themselves, additional considerations arise: insulation work often needs to be carried out on the exterior walls, whether it involves work on windows or the facade, or maintenance. In such cases, scaffolding must be used, and workers must be protected from danger, even when using tools, talking on the phone, or smoking – all potential ignition sources. Therefore, the equipment installed outside must be safe even when switched off and disconnected from the power supply. Animals, especially birds and rodents, can also pose a hazard, and vandalism is another risk.

[0009] The object of the invention is therefore to reduce the protection zone by suitable measures to such an extent that new installations of externally mounted heat pumps or outdoor units of split devices can be carried out in places where this has not previously been possible or permitted.

[0010] It should also be possible, for example, during work within the protection zone, to take measures that allow such work to be carried out safely, essentially to deactivate the protection zone, at least temporarily. This also applies to work necessitated by natural disasters, such as storm damage, floods, or earthquakes. Ideally, the need for a protection zone should be able to be temporarily eliminated by a specialist, after assessing the situation on site, and if necessary, permanently by adjusting the equipment accordingly.

[0011] The object of the invention is therefore to provide suitable measures for the dilution of refrigerant that has escaped due to leakage in the outdoor unit, which always reliably excludes the formation of an ignitable mixture.

[0012] The task is solved by an outdoor unit for a heat transfer system, comprising: A housing with a refrigeration circuit containing a flammable refrigerant and at least two separate housing sections, connections for electrical power supply and connections for refrigerant lines and / or heat transfer fluid lines, wherein a first housing section contains an air duct as a ventilation duct, a fan and an air-flowable fan heat exchanger, and wherein the air duct has a non-closable inlet area and a non-closable outlet area for outside air, and wherein a refrigerant compressor, an expansion valve and connections for fluid lines for at least one heat sink and at least one heat source are arranged in a second housing section, and the second housing section has at least one air inlet opening, and a separating device is provided between the first and the second housing section.which separates the two gas spaces of the first and second housing sections and, if applicable, further housing sections from each other, the separating device having at least one non-closable connecting opening that connects the first housing section to the second housing section, wherein the non-closable connecting opening in the separating device is connected to the air duct on the suction side of the fan, and the fan is designed and equipped in such a way that it can run continuously without stopping, the continuously running fan being able to be activated or deactivated by the installer depending on the installation situation.

[0013] This ensures a continuous airflow through the ventilation duct, guaranteeing diluted exhaust of any refrigerant that may have leaked out. This allows for a reduced safety zone around the outdoor unit, preventing any flammability or accumulation of refrigerant.

[0014] If the fan were not in operation, a minimum airflow through the air duct must be ensured so that even the smallest refrigerant leaks, for example at the evaporator in the air duct, do not lead to a critical accumulation of refrigerant and thus to exceeding the ignition limit for flammable refrigerants such as R290, R600a or R1260.

[0015] In calm conditions, the fan must operate at a minimum airflow rate to ensure adequate airflow. For typical outdoor unit dimensions, this is 200 to 2000 m³ / h, which corresponds to a very low speed of approximately 50 to 400 revolutions per minute. When the heat pump or air conditioning is not operating normally, or in the event of a malfunction, the fan must operate very efficiently.

[0016] However, this usually also means that the fan consumes a lot of electrical energy even when the heat transfer system is not needed or hardly needed. The following measures are designed to keep this electrical energy consumption as low as possible while simultaneously maintaining airflow and ventilation even in the event of power supply disruptions. For example, electrical energy consumption can be kept low by ensuring the fan can be operated continuously, at least at a low speed. To achieve this, however, information must be gathered and provided on when such minimal operation is practical.

[0017] Therefore, in certain configurations, at least one measuring device for the airflow velocity around the outdoor unit is provided, whereby this device either a measuring device which can perform measurements of air velocity in a physical-fluid-mechanical manner, or has a receiver for weather data in conjunction with an AI-supported evaluation unit, or contains a receiver for externally determined wind data and sent from there to the outdoor unit, or contains combinations of these means of determination and / or allows on-site observations.

[0018] Furthermore, a control option for continuous fan operation is provided, ensuring that the fan only supplies the additional airflow not already present through natural airflow. While the fan then runs practically constantly, it is relieved of some of its workload by the natural external airflow and consequently consumes very little electrical energy.

[0019] The necessary airflow is ensured within the framework of ATEX. ( AT mosphères Ex Plosives Directive 2014 / 34 / EU),Standardized in IEC 60079 Series "Explosive atmospheres", no protected area (without ignition sources etc.) is required, or a Zone 2 NE (neglibigle extent) if there is an air movement of 0.15 m / s.

[0020] The term "flow velocity" refers to the air speed of the ambient air flowing around the outdoor unit, provided there is no wind. The measuring device, which can consist of numerous individual devices based on different and redundant measurement principles, or which can be based on received weather data, artificial intelligence evaluation tools, or even on-site inspection and observation, preferably determines a three-dimensional flow profile. High precision is not required; it is only necessary to ensure that a defined minimum flow velocity is present. The system must be reliable and robust, and it must be protected from weather conditions such as snow, storms, and hail, as well as from animals.

[0021] Possible flow measuring devices include pitot tubes, vane anemometers, wind turbines and inexpensive LIDAR systems, whereby the expert can and will select a suitable measuring system from a large number of known and proven systems, taking into account his budget restrictions and the installation conditions.

[0022] Further features of the outdoor unit include the ability to reduce the fan speed when no leakage has occurred and no refrigerant is present in the outdoor unit's free space. Even then, the fan runs continuously, albeit at a significantly reduced speed, but it cannot be switched off. However, to determine the absence of leaks, measurements of gaseous refrigerant must be taken. Therefore, the outdoor unit is designed to... has at least one refrigerant detection device and a device for regulating and / or controlling the fan power, wherein this device for regulating and / or controlling is connected to the refrigerant detection device and the device for determining the flow velocity, and includes a computing and evaluation unit, or an adapted fan power of the fan can be set via the computing and evaluation unit.

[0023] In practical terms, this also means that if the refrigerant detection device detects a refrigerant concentration that suggests a leak, the fan is automatically increased to a higher speed, even if the heat transfer operation has to be stopped due to the detected leak and there is no longer a thermal load in the fan heat exchanger. The refrigerant detection device does not require a measurement of the absolute concentration; a simple increase in refrigerant in the air, i.e., the first derivative over time, is sufficient.

[0024] Further embodiments therefore provide for the fan to have its own emergency power supply, which is as uninterruptible as possible, and explosion protection equipment. The power supply is preferably based on a backup battery as an electrical emergency energy storage device for the emergency operation of the fan, the refrigerant detection device, the flow velocity measuring device, and the processing and evaluation unit, implemented as a battery, a supercapacitor (goldcap), or a capacitor as energy storage. The uninterruptible power supply can be provided as a separate unit or as part of the DC link of a converter.The power supply capacity is dimensioned at least so that in the event of a power failure during a simultaneous leak, the fan can continue to operate long enough to prevent dangerous concentrations of the escaping refrigerant from accumulating, either in the device itself or in its surroundings.

[0025] Further design features include the air duct in which the fan is located, as well as its inlet and outlet for ambient air. Typically, an air duct runs through an outdoor unit, containing the evaporator heat exchanger and fan in heat pump operation, or a condenser heat exchanger and condenser fan in air conditioning operation. Ideally, equipment capable of operating in both modes is used. The air duct may, but need not, follow a straight center line; curved shapes with bends are also common. Curves may be incorporated at the inlet and outlet of the fan air duct.

[0026] The purpose of these bulges is to create a suction effect in the fan air duct when ambient air flows laterally towards or around the outdoor unit. This suction ensures sufficient ventilation of the fan air duct even when the fan is switched off, preventing the formation of an ignitable mixture in the event of a refrigerant leak. Naturally, the direction of airflow and the wind speed of the ambient air must be taken into account, as these factors are related to the installation location and are measured.

[0027] In the present case, the air inlet and outlet areas are indeed arranged on opposite sides of the outdoor unit. However, it must be emphasized that the following configurations can also be applied analogously even if this is not the case, and the air inlet and outlet areas can be on the same side or at an angle to each other on different sides of the outdoor unit. Furthermore, the outdoor unit does not necessarily have to have a cuboid shape, but can also be of any shape. For example, such inlet or outlet areas can also be arranged on the top of the outdoor unit or distributed around its circumference. However, this is not relevant in the present case. Such unusual geometric shapes are also covered and are part of the invention, especially with regard to the following configurations.

[0028] If the air duct has bends or if there are multiple openings to or from the housing, this applies to each opening individually. Specifically, the air duct inlet is designed to be convex, creating positive pressure when the airflow is from the side, while the air duct outlet is designed to be concave, creating negative pressure. The resulting pressure difference, similar to that of aircraft wings, generates lift, which promotes airflow through the duct. In special cases, flaps similar to landing and takeoff flaps can also be incorporated to conserve fan energy during normal operation, depending on the airflow direction.

[0029] To improve the minimum flow rate, suitable measures can be taken regarding the shape of the outdoor unit housing. The Bernoulli effect is used to create a positive pressure side and a negative pressure side when measured laterally or at an angle, measured at the outer edges, if present, of the outdoor unit housing.

[0030] In further embodiments, the outer surface of the outdoor unit housing, in which the air duct inlet is located, is convex, and the outer surface of the outdoor unit housing, in which the air duct outlet is located, is concave, analogous to the fan openings. This further increases the pressure differential that drives the airflow through the duct and assists the fan.

[0031] In one embodiment of the outer unit, parts of the outer shell are therefore curved. Concave means "curved inwards" and convex means "curved outwards." This is a known way of describing, among other things, optical lenses when the curvature is applied along two axes and aircraft wings when the curvature is applied along one axis. In the present case, these curvatures do not need to cover the entire outer surface of the outer unit, and different radii of curvature can be used along the curves.

[0032] Depending on the installation location, it is necessary to determine which wind directions are possible, especially considering obstructions to airflow such as trees, walls, fences, and neighboring buildings. If the outdoor unit is located in front of a building, an airflow around the building can also create an upward current. If different shaped covers for the outdoor unit are available, a specialist can select one that, under normal circumstances, provides maximum support for the fan through suitable suction, thus saving fan energy, and ensures good airflow even without fan operation in the event of a leak. Suitable covers can also be retrofitted if the surrounding conditions change.

[0033] In the case of curvatures along two axes, the curvatures can differ. If one axis forms a concave curvature and the other a convex curvature, saddle shapes result. However, these are only used in exceptional cases within the scope of this invention, specifically when upward currents around obstacles mix with lateral currents. Those skilled in the art will take this into account depending on the terrain, especially on slopes.

[0034] Further improvements concern the fan bearings to minimize energy consumption at minimum speed. This also reduces the required emergency power supply if the fan is to continue running as long as possible during malfunctions. One embodiment provides for the fan to be mounted using magnetic bearings. The magnetic bearings are at least partially designed as active magnetic bearings, with a further magnetic bearing being designed as a passive magnetic bearing. The active magnetic bearing requires a constant power supply, which, however, can be connected to existing equipment thanks to the also provided emergency power supply. The active magnetic bearing can be equipped with active damping of vibrations and imbalances, in accordance with the state of the art, which enables very quiet operation; the continuous running of the fan will then not be disturbing even on pleasant summer evenings.In the case of a combined bearing with an active magnetic bearing and a passive magnetic bearing, a contactless bearing is provided which requires no maintenance and would require a maintenance-related shutdown of the fan.

[0035] Further design features concern the connecting opening. The inlet area of ​​the non-closable connecting opening from the second housing section has rounded edges to prevent airflow from being forced over sharp corners, while the outlet area of ​​the non-closable connecting opening into the first housing section is designed as a nozzle with a discharge funnel that first narrows and then widens. This has the advantage that the continuous airflow through the second housing section requires less energy and does not cause noise pollution from whistling sounds caused by vortex streets. This significantly increases the acceptance of a continuously running fan.

[0036] The invention also relates to a ventilation method. The descriptions of the apparatus apply accordingly. The object of the invention is achieved by a method for ventilating an outdoor unit of a heat transfer system, the outdoor unit comprising A housing with a refrigeration circuit containing a flammable refrigerant, at least one fan, a fan heat exchanger in an air duct, and connections for electrical power supply and connections for lines carrying refrigerant and / or heat transfer fluid, and a device for regulating and / or controlling the fan performance, wherein this regulating and / or controlling device is connected to a refrigerant detection device and a device for determining the airflow velocity, and includes a computing and evaluation unit, means for switching the outdoor unit fan between continuous operation and intermittent operation, wherein the fan is switched on during installation and can only be switched off or switched to intermittent operation by authorized maintenance personnel.

[0037] One aspect of the procedure provides that The intermittent operation is controlled by determining the airflow around the outdoor unit (1) and, depending on the determined airflow, by reducing the fan speed when sufficient ventilation of the outdoor unit (1) is ensured due to the airflow around the outdoor unit (1).

[0038] If reliable determination of the airflow around the outdoor unit cannot be guaranteed, the fan will remain switched on at least at minimum speed, and the fan's airflow rate will be regulated by the heat load of the heat exchange system using standard methods. The same applies if a refrigerant detection device has checked and determined that no refrigerant is present in the space surrounding the outdoor unit.

[0039] Further features relate to the use of the outdoor unit. This is used alternatively or additionally for temperature control in at least one animal barn, swimming pool, residential building, greenhouse, or data center. Since no safety zone is required, a wide variety of installation options are available, which can be adapted to the specific applications without restrictions. The large number of users with varying requirements reduces the time the fan has to run without a heat load, thus saving energy.

[0040] The invention is explained in more detail below with reference to 7 sketches. These show: Fig. 1 a view of the flow path in the outdoor unit, Fig. 2 the internal structure of an outdoor unit, Fig. 3 a sketch with a nozzle and a battery, Fig. 4 an outdoor unit with safety area from above, Fig. 5 an outdoor unit in flow from the side with two measuring devices, Fig. 6 an outdoor unit in flow from the side with airfoil profile, Fig. 7 a representation of various uses.

[0041] Fig. 1Figure 1 shows a perspective view of the outdoor unit 1 in regular operation, with the first housing section 2 on the left and the second housing section 3 on the right. The two housing sections are separated by a partition, here designed as a partition wall 4, in which the connecting opening 6 is located. In the first housing section 2, the fan 5 is arranged in the fan duct 16, which forms the first housing section 2. The airflow during operation is indicated by arrows. Not shown is the fan heat exchanger 7, against which the fan 5 draws or pushes the air. In winter, the heat exchanger cools the air, causing the refrigerant to evaporate, and in summer, it heats the air, causing the refrigerant to condense.

[0042] Fig. 2Figure 1 shows, in perspective and as an example, the interior of a typical outdoor unit, with the housing covers (shown as dashed lines) removed. Due to the desired negative pressure in the second housing section 3, the fan 5 creates negative pressure, thus drawing air through the fan heat exchanger 7. The connecting opening 6 between the first housing section 2 and the second housing section 3 is positioned where the negative pressure is highest, i.e., in the air duct of the first housing section between the fan heat exchanger 7 and the fan blades 5.

[0043] Fig. 3 Figure 1 shows a variant in which a connecting opening designed as a nozzle 17 is provided in the partition wall 4; this can be in addition to connecting openings 6, as in the preceding figures. Fig. 1 and Fig. 2shown, provided for. In the event of a larger leak, which is very rare but can occur under harsh external influences, pressure could quickly build up in the second housing section 3 and the nozzle 17 would lead to an accelerated discharge of the contaminated air and improve the mixing in the fan 5. Fig. 3 The diagram also shows a backup battery 18 for electrical power in case of a power outage, but the fan needs to continue running. Such a backup battery 18 can also be connected to a local grid as an energy storage device, both amplifying and balancing the power supply. This option is preferable for larger outdoor units and also when there is occasional surplus electricity from renewable energy sources on site. The primary purpose of the backup battery 18 is to keep the fan 5 running, ensuring continuous airflow.

[0044] Fig. 4The diagram schematically shows an outdoor unit 1 of a heat transfer system from above, with two safety zones S1 and S2 around the outdoor unit 1. The safety zones themselves are not part of the outdoor unit 1, but rather correspond to the installation recommendations for heat pumps with flammable refrigerants and are simplified here. Safety zone S1 is the safety zone around an unventilated or insufficiently ventilated outdoor unit 1, while safety zone S2 is the safety zone when ventilation can always be ensured, even during periods of non-operation. The aim is for safety zone S2 to be the primary factor in the installation.

[0045] The outdoor unit 1 comprises at least one air duct 16, in which a fan 5 and a fan heat exchanger 7 are arranged. Furthermore, the outdoor unit 1 contains a refrigerant circuit 20 in a tray or capsule, which is connected to a nozzle 17 that opens into the air duct 16. The refrigerant circuit has a connection opening 6 in the second section 3, which connects laterally or from above to the air duct 16 and is connected to its intake side, the suction side 13. When the fan 5 is operating, the air duct 16 always has a suction side 13 and a pressure side 12, and if refrigerant should escape due to a leak, it is vented away. With the typical airflow of a fan, a flammable mixture cannot form.

[0046] The situation is different if fan 5 is only operating to a limited extent or runs at high speed after prolonged operation at minimum speed because the heat pump's refrigeration circuit 2 is requesting heat or, if applicable, cooling from the fan heat exchanger 7, or also after the end of the heat demand and a cooling phase. In each of these cases, thermal stresses occur during changes in the operating state, which can tend to lead to minor damage and subsequent small leaks. It is precisely in these situations that adequate ventilation must be ensured; completely foregoing ventilation is out of the question. The same applies to periods of frost and defrosting during freezing and defrosting processes.

[0047] Furthermore, unless special measures have been taken, a safety zone S1 must be maintained in the immediate vicinity of outdoor unit 1. This zone must be free of ignition sources and sinks such as basement windows, as flammable refrigerants are typically heavier than air and sink to the ground, where they could accumulate and build up, potentially creating an ignitable zone. This significantly restricts the installation options for outdoor unit 1.

[0048] If, on the other hand, continuous ventilation can be ensured, or at least whenever refrigerant is detected in the air in outdoor unit 1, ideally even during a power outage, the safety zone S2 can be significantly smaller or even eliminated entirely. For this reason, the airflow around the outdoor unit is determined: if this airflow is sufficient to dilute any leaks that may have occurred, fan 5 must still run, but it only needs to be ensured that both housing sections 2 and 3 of outdoor unit 1 are still well ventilated. With sufficient airflow, this is possible with a lower fan speed, resulting in energy savings.

[0049] Fig. 5Figure 1 schematically shows an outdoor unit 1 of a heat transfer system from the side. This unit contains the refrigeration circuit 15 and has two air intake devices 18 on the roof of its housing to measure the airflow. For optimal efficiency, the outdoor unit 1 should not be installed facing away from the outlet and into the prevailing wind direction. Furthermore, according to conventional best practices, a sheltered location should be chosen, and a sufficient safety zone should be maintained around the outdoor unit 1. This applies particularly to the distance from windows and doors, but especially to nearby depressions where escaped refrigerant could collect. The latter is particularly relevant for basement windows.

[0050] The outdoor unit shown (unit 1) is installed differently, with a location with good airflow being preferred. In the event of a leak, the airflow ensures very rapid mixing with the ambient air, eliminating the need for the otherwise standard safety zone S1, which is a significant advantage. (See example in...) Fig. 5 An outdoor unit 1 is shown in which the refrigeration circuit 20, including a compressor and an expansion valve, is arranged in a basin 21 provided at the bottom of the housing. A constant suction is generated in the air duct 16 located above, which causes the air in the refrigeration circuit 20 to be vented upwards through the connecting opening 6 into the air duct 16. Lateral routing, as in the preceding figures, would also be possible. Furthermore, a pull operation through the heat exchanger 7 would be possible by arranging the air opening 6 between the fan 5 and the heat exchanger 7.

[0051] It is easily implemented, provided the airflow around the outdoor unit generates sufficient flow through the air duct, to change the flow direction depending on the direction of airflow around the outdoor unit. Only in calm conditions is the required suction generated solely by the fan 5, which draws in ambient air and pushes it against the fan heat exchanger 7. Consequently, the air from the refrigeration circuit 15 is directed onto the suction side 12 of the fan 5, and ventilation takes place. If the fan is only used to supplement the existing airflow, a fan 5 with fan blades can also be used, which can selectively and switchably move air in both directions, depending on the direction of airflow.

[0052] In this example, the flow detection device 18 consists of a pitot tube and a vane anemometer, both rotatably mounted and equipped with a vane for aligning with the wind direction and determining that wind direction. If good airflow around the outdoor unit 1 is present, which is measured and detected by the detection device 18, the fan 5 can remain solely for flow support, unless it needs to supply air to the fan heat exchanger 7 through the air duct 16 due to heat load.

[0053] An exception to this is when the refrigerant detection device 9 detects refrigerant inside the outdoor unit 1 and transmits this information to the computing and evaluation unit 10, which then decides at what power the fan 5 should be started up.

[0054] Fig. 6Figure 1 schematically shows an outdoor unit 1 from above, which, unlike the usual cuboid profile, has an airfoil profile. This airfoil profile can be more or less pronounced depending on the expected wind conditions, or it may only affect the inlet and outlet areas of the fan duct 16. The airflow 11 flows laterally around the outdoor unit 1. The airfoil profile creates a suction side 12 with low pressure, corresponding to the upper surface of an airfoil, and a pressure side 13 with high pressure, corresponding to the lower surface of an airfoil. Rounded edges 14 of the outdoor unit 1 smooth the airflow profile, and the reduction in vortex formation also results in a noise reduction.The resulting pressure profile, when the airflow is present, supports the airflow in the air duct 16, consequently reducing the power consumption of the fan 5 and, as a side effect, further reducing fan noise. In the case of frequently changing wind directions, suitable guide vanes, similar to those used as flaps in aircraft construction, can also be provided to optimally direct the wind into and through the fan duct.

[0055] Fig. 7Figure 1 shows a representation of various applications that can be operated simultaneously with an outdoor unit 1. These include an animal barn 19, a swimming pool 20, a residential building 21, a greenhouse 22, and a data center 23. Thus, this outdoor unit 1 is suitable not only in conjunction with an indoor unit of a residential building as a split heat pump, but also for other applications, either for heating or air conditioning, and in various ways during continuous operation. This results in an overall reduction in downtime and therefore also in economical continuous operation of the fan 15 due to shorter operating times and reduced airflow. Reference symbol list

[0056] S1 Unventilated safety area S2 Safety area 1 Outdoor unit 2 First housing section 3 Second housing section 4 Partition wall 5 Fan 6 Connection opening 7 Fan heat exchanger 8 Reserve battery 9 Refrigerant detection device 10 Computing and evaluation unit 11 Circulating air 12 Suction side 13 Pressure side 14 Edge 15 Refrigeration circuit 16 Air duct 17 Nozzle 18 Detection devices 19 Animal barn 20 Swimming pool 21 Residential building 22 Greenhouse 23 Data center

Claims

1. Outdoor unit (1) for a heat transfer system, comprising: - a casing with a refrigeration circuit containing a flammable refrigerant and at least two separate casing sections therein, - connections for electrical power supply and connections for refrigerant lines and / or heat transfer fluid lines, - in which an air duct (16), a fan (5) and an air-flow fan heat exchanger (7) are arranged in a first casing section (2), - and in which the air duct (16) has a non-closable inlet area and a non-closable outlet area for outside air, - and in which a refrigerant compressor and an expansion valve as well as connections for fluid lines for at least one heat sink and at least one heat source are arranged in a second casing section (3), - and the second casing section (3) has at least one supply air opening, - and between the first and the second casing section (2,3) a separating device (4) is provided which separates the two gas spaces of the first and second housing sections (2, 3) and optionally further housing sections from each other, - the separating device (4) has at least one non-closable connecting opening (6) which connects the first housing section (2) with the second housing section (3), - wherein the non-closable connecting opening (6) in the separating device (4) is connected to the air duct (16) on the suction side of the fan (5), , characterized by the fact that - the fan (5) is designed and equipped so that it can run continuously without stopping, - the continuously running fan can be activated or deactivated by the installer depending on the installation situation.

2. Outdoor unit (1) according to claim 1, characterized by the fact that- at least one measuring device (18) for the airflow velocity around the outdoor unit (1) and a control option for the continuous operation of the fan (5) are provided, 3. Outdoor unit (1) according to claim 2, characterized by the fact that - the measuring device (18) for the airflow velocity is either - a measuring device which can perform measurements of air velocity in a physical-fluid-mechanical manner, or - has a receiver for weather data in conjunction with an AI-supported evaluation unit, or - contains a receiver for wind data determined externally and sent from there to the outdoor unit, or - contains combinations of these measuring means and / or allows on-site observations.

4. Outdoor unit (1) according to one of claims 2 or 3, characterized by the fact thatit has at least one refrigerant detection device (9) and a device for regulating and / or controlling the fan power of the fan (5), wherein this device for regulating and / or controlling is connected to the refrigerant detection device (9) and the flow velocity detection device (18), and includes a computing and evaluation unit (10), or an adapted fan power of the fan (5) can be set via the computing and evaluation unit (10).

5. Outdoor unit according to one of claims 2 to 4, characterized by the fact that a reserve battery (8) is provided as an electrical emergency power storage device for the emergency operation of the fan (5), the refrigerant detection device (9) and the determination device (18) for the flow velocity as well as for the computing and evaluation unit (10) and the fan (5) has explosion protection equipment.

6. Outdoor unit according to one of claims 1 to 5, characterized by the fact thatthe fan (5) is arranged in an air duct (16) and that the inlet of the air duct (16) is convex, so that an overpressure is created when there is lateral airflow.

7. Outdoor unit according to one of claims 1 to 6, characterized by the fact that the fan (5) is arranged in an air duct (16) and that the outlet of the air duct (16) is concave, so that a negative pressure is created.

8. Outdoor unit according to one of claims 1 to 7, characterized by the fact that the outer surface of the housing of the outdoor unit (1), in which the inlet of the air duct (16) is arranged, is convex.

9. Outdoor unit according to one of claims 1 to 8, characterized by the fact that the outer surface of the housing of the outdoor unit (1), in which the outlet of the air duct (16) is arranged, is concave.

10. Outdoor unit (1) according to any one of claims 1 to 9, characterized by the fact that the fan (5) is mounted with a magnetic bearing.

11. Outdoor unit (1) according to claim 10, characterized by the fact that The magnetic bearing is designed as an active magnetic bearing.

12. Outdoor unit (1) according to claim 11, characterized by the fact that The active magnetic bearing is equipped with active damping of vibrations and imbalance.

13. Outdoor unit (1) according to one of claims 10 to 12, characterized by the fact that The magnetic bearing is designed as a maintenance-free and contactless combination of an active magnetic bearing and a passive magnetic bearing.

14. Outdoor unit (1) according to any one of claims 1 to 13, characterized by the fact that The inlet area of ​​the non-closable connecting opening (6) from the second housing section (3) has rounded edges that prevent flows from being guided over sharp edges (14).

15. Outdoor unit (1) according to any one of claims 1 to 14, characterized by the fact thatthe outlet area of ​​the non-closable connecting opening (6) into the first housing section (2) is equipped as a nozzle (17) with an outlet funnel that first narrows and then widens.

16. Method for ventilating an outdoor unit (1) of a heat transfer system, the outdoor unit (1) comprising: - a housing with a refrigeration circuit (15) containing a flammable refrigerant, - at least one fan (5), a fan heat exchanger (7) in an air duct (16), - connections for electrical power supply and connections for lines carrying refrigerant and / or heat transfer fluid, and - a device for regulating and / or controlling the fan power of the fan (5), - wherein this regulating and / or controlling device is connected to a refrigerant detection device (9) and a measuring device (18) for the airflow velocity, if present, and - comprising a computing and evaluation unit (10), - means for switching the fan of the outdoor unit between continuous operation and intermittent operation, characterized by the fact that- the fan is switched on during installation and can only be switched off by authorized maintenance personnel or switched to intermittent operation.

17. Method according to claim 16, characterized by the fact that - the intermittent operation is controlled by determining the airflow around the outdoor unit (1) and - depending on the determined airflow, the fan is reduced if sufficient ventilation of the outdoor unit (1) is ensured due to the airflow around the outdoor unit (1).

18. Method according to one of claims 16 or 17, characterized by the fact that - is checked by at least one refrigerant detection device (9) whether there is refrigerant in the free space of the outdoor unit and, if this is not the case, the fan is reduced to at least minimum speed.

19. Use of an outdoor unit (1) according to one of the preceding claims alternatively or additionally for temperature control for at least - one animal barn (9), - one swimming pool (10), - one residential building (11), - one greenhouse (12), - one data center (13).

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