Heat pump and method for installing it
Patent Information
- Application Number
- ES2019218593T
- Authority / Receiving Office
- ES · ES
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2019-12-20
- Publication Date
- 2026-10-07
- Estimated Expiration
- 2039-12-20
Smart Images
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Abstract
Description
Heat pump and method for installing it Technical field The present invention relates to a heat pump and methods for installing it. Background of the technique The development of modern heat pumps faces a wide range of requirements due to environmental and technical challenges. On the one hand, heat pumps must operate as efficiently as possible, and on the other hand, the refrigerant used in them must avoid any environmental risks, such as ozone depletion or negatively impacting global warming. To address these requirements, the refrigerants used in modern heat pumps were changed from non-flammable refrigerants, such as R410A, to flammable refrigerants, such as R32, which operate more efficiently than non-flammable refrigerants, while achieving a reduction (or elimination) of the possibility of ozone layer destruction and a reduction of the possibility of global warming (hereafter referred to as "GWP"). However, when switching from non-flammable to flammable refrigerants, extra care must be taken when handling the latter. In fact, a leak of flammable refrigerant into an interior space where the heat pump, or at least part of the heat pump such as an indoor unit, is installed will cause the refrigerant concentration inside to increase, potentially leading to the formation of a flammable zone. Such a concentration of leaking flammable refrigerant is particularly dangerous, as flammable refrigerant often has a higher density than air at atmospheric pressure. Consequently, the leaking flammable refrigerant accumulates at the bottom of the interior space, i.e., on the floor. This can lead to fire and pose risks to occupants, the building, and other hazards. Therefore, it is desirable to avoid the formation of a flammable concentration zone in an indoor space. For this purpose, current heat pumps used in indoor spaces, as described, for example, in European patent no. EP 3,222,941 A1, are equipped with complex sensor systems, and it is necessary to install at least one ventilation system, such as a fan, in the indoor space. These commonly used systems continuously measure the refrigerant concentration within the indoor space and, in the event of a flammable refrigerant leak, activate the fan to circulate air and disperse the leaking flammable refrigerant. Consequently, the formation of a flammable concentration zone within the indoor space can be prevented. However, European patent no. EP 3,222,941 A1 requires a highly complex system, as well as continuous monitoring. To avoid such a complex heat pump system, French patent no. FR 2,827,948 B1 describes an alternative approach. This approach involves a housing containing at least part of the heat pump system and a sealed duct opening to the exterior of the building, in which at least the indoor unit of the heat pump is mounted. This provides an air conditioning device where any refrigerant leakage can be vented outside the building. However, this introduces additional problems and risks due to potential duct blockage caused by contamination, animals, dust, or similar elements surrounding the duct opening on the exterior of the building. This is particularly dangerous when refrigerant leaks inside the housing and cannot be vented to the environment. This can lead to increased refrigerant pressure within the housing and a greater risk of fire. To ensure the safe application of heat pumps and / or at least their indoor units within indoor spaces, international standards have been established, specifically IEC 60335-1 (Ed5) and IEC 60335-2-40 (FDIS Ed6). These standards define the international rules for the required dispersion height of potential refrigerant leaks within heat pump systems. The aim is to prevent the accumulation of flammable refrigerant, especially in small indoor spaces. By defining a minimum evacuation height, which depends on the available floor space in the interior space and the amount of flammable refrigerant used in the heat pump, sufficient dispersion of the flammable refrigerant, which has a higher density than air at atmospheric pressure, can be ensured within an interior space. When considering a flammable refrigerant that has a density greater than air at atmospheric pressure, the aforementioned international standards, which are exemplified in greater detail, for example, in European patent document no. EP 3,139,105 A1, define accordingly the general rule that, when there is a fixed interior space floor area, dilution is improved with a greater exhaust height and, therefore, the possible formation of a flammable concentration zone is reduced. In light of this descriptive report, "small interior space" means a room, for example, in a house, such as a private dwelling, that has a total space equal to or less than 200 m2. However, currently available systems still require ventilation to meet these requirements in small rooms and to adequately disperse any refrigerant leaks. Consequently, installing a simple and safe heat pump system, or at least an indoor unit, in particularly small indoor spaces while using efficient, non-flammable refrigerants is challenging without additional measures such as ventilation systems. Australian patent document no. AU 459154 B2 describes a prefabricated modular air conditioner suitable for installation between the roof and the top slab of a building structure's roof, and which is easily installed or removed through the opening in the roof slab, thus requiring less labor for installation and being easily accessible for repair and maintenance. French patent document no. FR 3.070.755 A1 describes a cold production installation or a heat pump, installed in a room and equipped with a sealed box containing the entire cooling system, said box being connected by a sealed duct to the outside of the building. European patent document no. EP 3,139,105 A1 describes an air conditioning apparatus that includes an indoor unit in which an indoor heat exchanger is mounted and which uses a flammable refrigerant having a density greater than air at atmospheric pressure, wherein the air conditioning apparatus ensures safety while filled with an effective amount of refrigerant. Compendium of the invention In view of the foregoing, an object of the present invention is the provision of a heat pump having a simple configuration and a method for installing it, which allows avoiding the concentration of flammable refrigerant leaks within a small interior space. In other words, the key idea of the present invention is to provide a simple heat pump configuration and a method for installing it, which achieve sufficient and reliable dilution of flammable refrigerant leaks within a small interior space and thus at least reduce the risk of ignition. This object is solved by means of a heat pump according to claim 1 and / or a method according to any of claims 11 to 13. According to a first aspect of the invention, a heat pump comprises a refrigerant circuit configured to circulate a flammable refrigerant and an indoor unit configured to be disposed in an indoor space. The refrigerant circuit comprises a compressor, a utilization-side heat exchanger, an expansion device, and a source-side heat exchanger connected by ducts. Furthermore, the indoor unit comprises an outer casing having a top portion and a sealed container housed within the outer casing, wherein the sealed container has a bottom portion and a top portion and houses at least one of the following: the compressor, the utilization-side heat exchanger, the expansion device, and the source-side heat exchanger.In this context, the sealed container houses at least the potential leak points, such as the aforementioned components (compressor, load-side heat exchanger, expansion device, and heat source-side heat exchanger), weld points, pipes with sharp bends, and the like. The sealed container has a vent opening to allow any refrigerant leak to escape from the outer casing of the indoor unit. The "expansion device" should not only be understood to cover an expansion valve, but should also cover a capillary tube or similar that expands the compressed refrigerant within the refrigerant circuit. A heat pump can be, for example, an air-source heat pump that uses air as the heat source or a geothermal heat pump that uses the ground as the heat source. Heat pumps can be used, for example, for domestic hot water production, air conditioning (heating and / or cooling), and similar applications. In an air-source heat pump, a heat source unit is provided, which may include the compressor, expansion valve, and heat source-side heat exchanger of the refrigerant circuit. The heat source unit may be configured as an outdoor unit located outdoors. However, there are also air-source heat pumps in which the heat source unit is physically located indoors, although it exchanges heat with outside air as the heat source.The indoor unit is configured to be installed in an interior space that includes a utilization-side heat exchanger. In a geothermal heat pump, the indoor unit may include the entire refrigerant circuit, including the compressor, expansion valve, heat source-side heat exchanger, and utilization-side heat exchanger. Furthermore, the heat pump can be an enhanced-seal refrigeration system. An "enhanced-seal refrigeration system" is a system in which the indoor unit(s) are designed and manufactured to ensure a high level of confidence that large refrigerant leakage rates will not occur during normal and abnormal operation. Refrigeration systems that meet all the conditions defined in clause 22.125 of IEC 60335-2-40:2018 will be considered enhanced-seal refrigeration systems. It should be understood that the "flammable refrigerant" described above has a density greater than that of air at atmospheric pressure. A "flammable refrigerant" may be a refrigerant classified as class A2L, A2, or A3 according to ISO 817, in particular a refrigerant classified as class A2L. The arrangement described above provides a simple heat pump configuration. This simple configuration ensures the safe operation of the indoor unit, which is designed for indoor use, as any potential leak of flammable refrigerant is safely collected in a sealed container. If the amount of flammable refrigerant collected is sufficiently high, it is automatically vented outside the indoor unit's outer casing into the interior space at a predetermined location. This allows for adequate dispersion within the interior space, reducing the risk of fire. Such a configuration is particularly advantageous in small indoor spaces, such as in residential applications. Consequently, an appropriate exhaust height for the refrigerant leak can be easily determined.In this context, the exhaust height can be understood as the sum of the installation height and the exhaust displacement. The installation height is the height of the bottom of the unit (e.g., the indoor unit or, more specifically, the outdoor casing) from the floor of the room after installation. For portable or floor-mounted indoor units, the installation height is, for example, 0 m. For window-mounted indoor units, the installation height might be 1 m; for wall-mounted indoor units, it might be 1.8 m; and for ceiling-mounted indoor units, it might be 2.2 m. The exhaust displacement is the distance from the bottom of the indoor unit or the outdoor casing (appliance) to the exhaust opening through which refrigerant can escape from the indoor unit in the event of a leak.The present invention allows for appropriate adjustment of the exhaust displacement. The sealed container further comprises a chimney having a first and a second end. The first end of the chimney is in fluid communication with the interior of the sealed container, and the exhaust opening of the sealed container is located at the second end of the chimney to evacuate the refrigerant leak into the interior space. The "chimney" can be understood as a rigid or flexible conduit. Alternatively, the chimney can be composed of several parts that are fluidly connected, for example, hermetically sealed. That is, the chimney can comprise a plurality of sections that are fluidly connected to each other. At least one section of the chimney can be flexible. The use of a plurality of sections improves construction flexibility, since the sealed container can be arranged in different positions within the indoor unit, while the chimney can be adapted using different sections that still maintain a sufficiently high position for the exhaust opening. Having a chimney composed of several seamlessly connected parts also allows the exhaust opening height to be adjusted according to the installation situation. This means that, for example, when the indoor unit is wall-mounted, a longer or shorter chimney may be required to achieve the desired exhaust opening height compared to situations where the indoor unit is floor-standing. For instance, a platform can raise the indoor unit to a higher position (measured from the floor of the interior space), so the exhaust opening height also increases by the height of the platform. Consequently, a shorter chimney may be needed to achieve the desired exhaust opening height. In one embodiment, the chimney extends from an interior portion of the outer casing, through a wall of the outer casing, to the exterior of the outer casing. Having a chimney in fluid communication with an interior portion of the sealed enclosure, and an exhaust vent at the opposite end of the chimney, allows for sufficient dilution within the interior space while maintaining a simple heat pump layout. Furthermore, the chimney's design, which extends or diverts the exhaust vent to or beyond the outer casing of the indoor unit, provides greater design flexibility and allows for more adaptable indoor unit placement. In other words, the chimney enables adjustments to the exhaust vent's position relative to the sealed enclosure, allowing, for example, the exhaust vent and sealed enclosure to be positioned in various locations within the indoor unit. According to a second aspect, the exhaust opening is located further from the bottom than from the top of the sealed container to evacuate the refrigerant leak into the interior space. The refrigerant leak primarily accumulates within the sealed container, which initially prevents it from escaping outside the indoor unit and into the interior space. If the flammable refrigerant continues to leak and flow into the sealed container, it can be vented through the exhaust opening into the interior space at a sufficiently high position. This facilitates the dispersal of the flammable refrigerant within the interior space and reduces the risk of a flammable refrigerant buildup. According to a third aspect, the exhaust opening is located above the top of the outer casing. For example, the chimney extends from the top of the outer casing of the indoor unit or along one side of the outer casing of the indoor unit, so that the exhaust opening at the second end of the chimney is separated from the top of the outer casing of the indoor unit. It is beneficial for the second end of the chimney to also include at least one of the following: a cover over the exhaust opening, a screen over the exhaust opening, a U-shaped duct, a 90° turning duct, and a self-opening cap. These components close the exhaust opening at the second end of the chimney and automatically open it to evacuate the coolant leak, while preventing contamination inside the chimney. Alternatively, a one-way valve may be provided in the chimney that opens automatically to evacuate the coolant leak, while preventing foreign matter and / or moisture from entering the chimney. Having an exhaust opening located above the top of the outer casing further increases the discharge height (exhaust height) of the refrigerant leak into the indoor space, thus further reducing the risk of a dangerous concentration of flammable refrigerant inside. In addition, it allows for greater flexibility in the placement of the indoor unit. According to a fourth aspect, the utilization-side heat exchanger is housed in the sealed container. The placement of the utilization-side heat exchanger within the sealed container reduces the risk of uncontrolled leakage of flammable refrigerant into the indoor unit and subsequent uncontrolled leakage into the interior space. Furthermore, heat exchange within the interior space can take place in a safe environment, specifically within the sealed container, which is connected to the outside of the indoor unit via the exhaust port. Therefore, any potential refrigerant leaks from the utilization-side heat exchanger or the duct connecting it to the rest of the refrigerant circuit can be safely collected within the sealed container and vented and diluted through its exhaust port. This provides a simple and safe heat pump system configuration without the need for any additional ventilation. According to a fifth aspect, a connection of at least one of the compressor, the utilization-side heat exchanger, the expansion device, and the heat source-side heat exchanger, which is / are housed in the sealed container, with the ducts, is housed in the sealed container. The more components and their connections to the remaining refrigerant circuit are contained within the sealed container, the lower the risk of an uncontrolled release of flammable refrigerant. Therefore, including the piping and its connection to each component of the refrigerant circuit within the sealed container provides a safer arrangement and ensures that every connection point between the components inside the sealed container and their piping connecting to the outside is also protected. Consequently, a leak of flammable refrigerant can be prevented from flowing uncontrollably into the interior space and from being evacuated to an insufficient height to dilute the flammable refrigerant. According to a sixth aspect, particularly applicable to improved airtightness refrigeration systems, the exhaust opening is located at least 1.8 m above the lower surface (floor) of the interior space when the outdoor casing of the indoor unit is installed. Alternatively, the exhaust opening is located at least 1.8 m below the lower surface (floor) of the interior space when the outdoor casing of the indoor unit is installed and a fan is provided to circulate air within the interior space. For example, if you have a floor-standing indoor unit, the height can be measured from the bottom surface or floor of the room, which is in direct contact with the unit's base plate or stand. In this case, the installation height is 0 m, and the exhaust vent height corresponds to the exhaust offset. However, different indoor unit placements are also applicable, such as on a shelf or platform. In these cases, the exhaust vent height is calculated not only from the platform in contact with the indoor unit but also from the floor of the room. Even when several elements are located between the indoor unit (including the exhaust vent) and the floor of the room, the exhaust vent height is calculated from the floor of the room to the exhaust vent, regardless of the number of elements in between.To put it another way, the exhaust opening height (exhaust height) is calculated as the sum of the indoor unit installation height and the exhaust displacement (see above). Therefore, when the indoor unit is located within the interior space, positioning the exhaust opening at least 1.8 m above the floor ensures a sufficiently high exhaust opening. This allows for adequate dispersion of any flammable refrigerant leakage. This is particularly relevant for small interior spaces, for example, an interior space with a surface area of less than 200 m². On the other hand, when the indoor unit is positioned within the interior space such that the exhaust opening is located below 1.8 meters from the floor of the interior space, and a fan is installed in the interior space, the fan ensures that the air in the interior space is circulated, thus sufficiently diluting any refrigerant leakage and keeping the refrigerant concentration in the interior space below the ignition point. According to a seventh aspect particularly applicable to refrigeration systems without improved sealing, the exhaust opening is located at a height above the floor of the interior space, when the outer casing of the indoor unit is installed, which is equal to or greater than the largest result of the following formulas: Considering these formulas, "H" reflects the minimum height of the exhaust opening measured from the floor of the interior space, "mc" reflects a mass of the refrigerant in the refrigerant circuit, and "LFL" reflects a low flammability level coefficient, where, for example, the commonly applied low flammability coefficient for R32 is 0.307. With this type of arrangement, it is possible to provide a sufficiently high exhaust opening from the sealed container within a room, while also taking into account the amount of refrigerant used in the system. In many cases, this arrangement eliminates the need for additional mechanical elements, such as a fan or similar ventilation system, within the room. This results in a simple and safe heat pump. Regarding this tenth point, the minimum height of the exhaust opening must be at least 0.6 m. The term "sealed" as described herein should not necessarily be understood to exclude any openings. Therefore, according to an eighth aspect, the cumulative area of all openings in the sealed container, other than the escape opening, is less than 5 cm². In this context, "openings" are to be understood as openings that connect the interior of the sealed container to an environment outside the sealed container. Furthermore, no single dimension, such as the diameter, of such an opening considered in the cumulative area is greater than 0.1 mm. Consequently, openings with a dimension, such as a diameter, of less than 0.1 mm are not considered openings through which a refrigerant leak could escape. According to a ninth aspect, the ducts connecting at least one of the compressor, the utilization-side heat exchanger, the expansion device, and the heat source-side heat exchanger, which is / are housed in the sealed container, pass through the exhaust opening for connection to the rest of the refrigerant circuit. According to this arrangement, a simple sealed container configuration is possible, in which all the elements within it are simply connected by conduits that enter and exit the sealed container through its exhaust opening. Therefore, other openings that need sealing can be avoided, and a simple, properly sealed end arrangement can be achieved. According to a tenth aspect, the refrigerant circuit contains the flammable refrigerant and / or the refrigerant consists of or comprises R32. According to one embodiment, the sealed container according to any of the above aspects is made of at least a single sheet of metal, a single drawn sheet of metal, or molded material. When at least one of the following components is housed within the sealed container: the compressor, the utilization-side heat exchanger, the expansion device, and the heat source-side heat exchanger, there is a risk of condensation (sweating) occurring on the respective component. This condensation can accumulate in the sealed container. To counteract this accumulation, several measures can be taken, either independently or in conjunction with one another. For example, the component housed within the sealed container, such as the utilization-side heat exchanger, can be insulated to prevent, or at least reduce, condensation on its surfaces. Another measure is to provide a heater within the sealed container so that any condensation that accumulates can evaporate and be drained through the exhaust opening.An additional measure is to provide a drain conduit or drain opening to drain water from the sealed container, the drain conduit / opening comprising a controlled valve. The controlled valve must allow fluid to flow from the sealed container, through the drain conduit / opening, to the outside of the sealed container, but must prevent refrigerant from escaping through the drain conduit / opening following a refrigerant leak within the sealed container. This prevents any moisture from entering the sealed container, thus reducing or even eliminating the likelihood of condensation forming on the components inside the sealed container, and allows for the drainage of any condensation that accumulates within the sealed container. According to an eleventh aspect, a method for installing a heat pump as described above comprises the step of installing the outer casing of the indoor unit of the heat pump in the interior space, wherein the exhaust opening of the sealed container is arranged at least 1.8 m above the floor of the interior space. This simple and safe heat pump configuration provides sufficient and controlled dilution of any potential flammable refrigerant leak into the indoor space. This prevents a dangerous concentration of flammable refrigerant. Furthermore, this type of configuration eliminates the need for additional mechanical ventilation in a small indoor space, such as one with an area of 200 m². Additionally, the exhaust opening at this height eliminates the need for mechanical ventilation, such as the use of a fan in the indoor space, when the indoor unit is part of a refrigeration system with enhanced airtightness (see above). According to a twelfth aspect, a method for installing a heat pump as described above includes the step of installing the outdoor casing of the heat pump's indoor unit in the interior space, where a fan is placed to at least circulate the air. In this context, it should be emphasized that the fan does not need to replace the air in the interior space, i.e., actively ventilate the interior space, although such ventilation can be provided. However, the fan induces air movement so that the refrigerant and the room air mix. As a result, the refrigerant is diluted, and the risk of refrigerant ignition is reduced. The fan can be part of a ventilation system that actively ventilates the interior space.Furthermore, the fan can be activated or run continuously upon detection of a refrigerant leak. When the fan is located in the indoor space, the exhaust opening can even be positioned less than 1.8 m below the floor of the indoor space. This is particularly relevant for indoor units of refrigeration systems with improved airtightness. Thanks to this arrangement, a compact and safe configuration can be achieved which, with the help of the fan, sufficiently dilutes the air / refrigerant mixture within the interior space. This configuration also counteracts a potential concentration of flammable refrigerant leaks within the interior space. According to a thirteenth aspect, a method for installing a heat pump as described above comprises the step of installing a heat pump and includes the step of installing the outer casing of the indoor unit of the heat pump in the interior space, wherein the exhaust opening of the sealed container is arranged at a height above the floor of the interior space, when the outer casing of the indoor unit is installed, which is equal to or greater than the greater of the following formulas: In this context, "H" represents the minimum height of the exhaust opening measured from the floor of the interior space, "mc" represents the mass of refrigerant in the refrigerant circuit, and "LFL" represents a lower flammability limit. "SF" represents a safety factor, where SF is 0.75, and "A" represents the area of the interior space, where A is, for example, 200 m². This applies particularly to indoor units of refrigeration systems without enhanced sealing. Furthermore, in these cases, the minimum height of the exhaust opening must be at least 0.6 m. This simple and safe heat pump configuration provides sufficient and controlled dilution of any potential flammable refrigerant leak into the interior space. This prevents a dangerous concentration of flammable refrigerant. Furthermore, this configuration eliminates the need for additional mechanical ventilation, such as a fan, within a small interior space. Brief description of the drawings A more complete appreciation of the invention and many of its related advantages will easily be obtained as it is better understood by reference to the following detailed description, when considered in connection with the accompanying drawings. Figure 1 shows a general structure of an indoor unit of a heat pump according to the present invention. Figure 2 shows the general structure of the indoor unit of Figure 1 omitting the outer casing of the indoor unit and part of the sealed container. Figure 3 shows a top part of the indoor unit from Figure 2, but with the sealed container arranged on it. Figure 4A shows the sealed container from Figure 3 in isolation. Figure 4B shows the sealed container of Figure 4A omitting the top, bottom, and two side walls. Figure 5 shows another embodiment of the partially sealed container in an exploded view. Figure 6 shows an alternative embodiment for the arrangement of the chimney in the indoor unit. Figure 7 shows another alternative embodiment of the indoor unit, which is not part of the claimed invention, having a sealed container protruding from the top of the outer casing of the indoor unit. Figure 8 shows an alternative arrangement of the conduits to and from the sealed container, which is not part of the claimed invention, passing through the exhaust opening. Detailed description of achievements Several embodiments of the heat pump of the present invention will now be described in detail. In general, a heat pump comprises a refrigerant circuit which, in the present embodiments, is configured to circulate a flammable refrigerant. The refrigerant used in the example embodiments of the present invention is R32, as R32 allows for efficient heat exchange while also having a low GWP. R32 is typically denser than air at atmospheric pressure. Therefore, R32 tends to concentrate in the lower parts of spaces or volumes. The problems arising from the density of R32 and its flammability characteristics will be described in more detail below. Furthermore, other flammable refrigerants may also be used in the context of the present invention. The refrigerant circuit used in the heat pump of the present invention corresponds to a commonly known refrigerant circuit, comprising at least one compressor, a load-side heat exchanger (e.g., for domestic hot water or for space heating / cooling, such as air conditioning or underfloor heating), an expansion device (e.g., a main expansion valve), and a heat source-side heat exchanger (e.g., an outdoor air heat exchanger or a geothermal heat exchanger). All elements are connected by pipes so that the refrigerant can flow from one component to another and can exchange heat with a second medium. The example embodiments of the heat pump described below refer to an air heat pump, in which the aforementioned elements of the refrigerant circuit are housed separately in an outdoor unit and an indoor unit. The example outdoor unit (not shown) houses at least the main expansion valve, the compressor, and the heat source-side heat exchanger, while the example indoor unit 10, which will be described in more detail below, houses at least the utilization-side heat exchanger 19. This provides a quiet and compact design for the indoor unit 19. However, other configurations and refrigerant circuit arrangements are also applicable in the indoor unit 10 and the outdoor unit. Figure 1 illustrates an example embodiment of such an indoor unit 10 of an air-source heat pump. Figure 1 shows a floor-mounted indoor unit 10 for producing hot water, for example, for domestic hot water and / or space heating. This unit can be located in the floor of an interior space, i.e., a room within a building, where hot water is to be produced. However, a wall-mounted indoor unit is also applicable. The hot water produced can be used, for example, for bathroom applications (shower, bathtub, etc.), in the kitchen, or for underfloor heating systems in a house. Figure 2 illustrates the general configuration of the floor-standing indoor unit 10 shown in Figure 1, in which the side portion of the outer casing 15 has been removed. Starting with the floor (not shown) of the interior space, on which the indoor unit 10 is placed, an insulated tank 11 is provided on a base plate 12, on which the outer side casing 15 of the indoor unit 10 (not shown in Figure 2) can be mounted. The insulated tank 11 can be made of stainless steel and may be covered with an insulating material. The insulated tank 11 stores the domestic hot water generated by the indoor unit 10 and effectively prevents rapid cooling of the generated hot water. This ensures that hot water is readily and continuously available at any time. In the example embodiment of the floor-standing indoor unit 10, the insulated tank 11 can have a volume of 180 to 230 liters. However, this application is not limited to this, and other volumes are also applicable. A drain pan 13 is provided above the insulated tank 11 to allow any condensation water to drain and collect in the pan. In the example embodiment of Figures 1 and 2, all the elements necessary for producing hot water within the indoor unit 10 are arranged above the drain pan 13 and will be described in more detail below. Above this, the outer casing 15 of the indoor unit 10 comprises a top part 16 forming the top of the outer casing 15 of the indoor unit 10. Water connection pipes 14 protrude from the upper portion 16 of the outer casing 15 to provide an upper connection to the indoor unit 10 of the heat pump. Specifically, the water connection pipes 14, in this embodiment, can form part of a closed circuit and connect the indoor unit 10 to at least one heating application, such as underfloor heating, a radiator, an air heater, or the like. Furthermore, a coil submerged in a domestic hot water tank (insulated tank 11) can form part of this closed circuit for heating the water contained in the domestic hot water tank. Consequently, the water connection pipes 14 allow, for example, relatively hot water to flow out of the indoor unit 10 to its desired application within the house, and allow relatively cold water to flow into the indoor unit 10.A domestic hot water pipe 26 and a fresh water pipe 27 are provided to, respectively, draw hot water from the domestic hot water tank and supply fresh water to the domestic hot water tank to refill it. In the present embodiment, the closed-circuit water flowing to the indoor unit 10 is guided through the utilization-side heat exchanger 19 of the indoor unit 10. Within this utilization-side heat exchanger 19, the water exchanges heat with the refrigerant in the refrigerant circuit, in this case R32, and is therefore heated. Subsequently, the heated water leaves the utilization-side heat exchanger 19 and flows through a coil arranged in the insulated tank 11, thereby heating the water contained in the insulated tank 11. Alternatively, or as in the present embodiment, the heated water can flow directly to at least one heating application, such as underfloor heating, a radiator, an air heater, or the like.If necessary, a switching device can be provided so that the heated water can circulate through the coil to produce domestic hot water or to at least one space heating application, depending on demand. If hot water is required for a domestic application, such as tap water, it can be drawn from the insulated tank 11 and conveyed through the domestic hot water pipe 26 to the outside of the indoor unit 10 and used for domestic purposes, for example, in the same room of the house or in a different one. To refill the insulated tank 11, cold water is flowed into the tank through a freshwater pipe 27. Of course, the invention is not limited in this respect, and other embodiments are conceivable. To achieve the above-mentioned heat exchange between the hot gaseous R32 and the cold water inside the utilization-side heat exchanger 19, hot gaseous R32 is flowed from the outdoor unit (not shown) into the utilization-side heat exchanger 19 through a gaseous refrigerant line 17. Consequently, heat can be exchanged between the hot, gaseous refrigerant entering the utilization-side heat exchanger 19 through the gaseous refrigerant line 17 and the cold water within the utilization-side heat exchanger 19. Conversely, not only is the water heated, but the refrigerant temperature is also reduced accordingly. Depending on the desired application, the heat exchange within the utilization-side heat exchanger 19 can be carried out in either parallel or counterflow. Due to the cooling of the refrigerant during heat exchange within the utilization-side heat exchanger 19, the refrigerant becomes liquid, exits the utilization-side heat exchanger 19 through a liquid refrigerant line 18, and then exits the indoor unit 10 and returns to the outdoor unit (not shown) of the refrigerant circuit. There, the refrigerant temperature is increased again due to compression and heat exchange within the heat source-side heat exchanger of the refrigerant circuit. The refrigerant can then be used to perform further heat exchange with cold water inside the utilization-side heat exchanger 19 to produce, for example, hot water. Other commonly known components of an indoor air-purging heat pump unit, such as air vent valves, a magnetic filter, a controller, a three-way valve, a flow sensor, an expansion vessel, a pressure sensor, a backup heater, a connection terminal, a switch box, a user interface, a circulation pump, etc., are not relevant to the description of the example embodiments and are well known to a person skilled in the art; therefore, further description of these components will be omitted. Consequently, some of these components are also not shown in the drawings for guidance purposes. Figure 3 shows a top portion of the indoor unit 10 of the exemplary embodiment shown in Figures 1 and 2. It is clear from Figure 3 that the indoor unit 10 comprises a sealed container 20, which is housed within the outer casing 15 of the indoor unit 10. This sealed container 20 is an airtight container, which in the present embodiment comprises a lower portion 21 and an upper portion 22 and can house at least one of the following: the compressor, the utilization-side heat exchanger 19, the expansion device, and the heat source-side heat exchanger. Although the present embodiment shows the sealed container configured as a sheet metal box, other configurations are also conceivable. One such example is shown in Figure 5. In this example, the sealed container 20 can be made of at least two members of different materials. The two members can comprise a housing 29 made, for example, of plastic material and a lid 30 made, for example, of sheet metal. The housing 29 replaces, for example, four of the sheet metal parts of the embodiment shown in Figure 4, specifically those resembling the bottom portion 21, the top portion 22, and three of the side walls 28. A remaining side wall 28, particularly the one through which the conduits 14, 17, and 18 pass and which comprises the sealing contact areas 25, is retained as the sheet metal lid 30. In contrast to a sheet metal box, where seals are required between each and every sheet metal part, this embodiment only requires a seal 31 between the housing 29 and the lid 30.In this embodiment, the chimney 24 is shown to be relatively short so that the exhaust opening 23 is located only slightly above the top part 22. However, in other embodiments, the chimney 24 can be extended by means of a tube or duct in order to place the exhaust opening 23 in a higher position, similar to that shown in the embodiment of Figure 3. In the example embodiments described herein, the sealed container 20, for example, houses and completely covers the utilization-side heat exchanger 19. It should be noted in this regard that the sealed container is not shown in Figure 2 except for the side walls 28 through which the gaseous refrigerant line 17, the liquid refrigerant line 18, and the water connection lines 14 pass. Furthermore, the sealed container 20 is shown in isolation in Figure 4A and, in order to show its interior, with the bottom part 21, the top part 22, and two of the side walls 28 removed in Figure 4B. However, it is also possible that at least one, or all, of the compressor, expansion valve, and heat source-side heat exchanger are also housed within the sealed container. In such a configuration, the sealed container 20 can then be the outer casing of the indoor unit 10. The provision of a sealed container 20 that completely covers and houses the utilization-side heat exchanger 19 of the indoor unit 10 prevents problems related to potential refrigerant leaks within the utilization-side heat exchanger 19. This configuration prevents an uncontrolled escape of flammable refrigerant, in this case R32, into the interior space where the indoor unit 10 is located. The water and refrigerant lines entering or leaving the sealed container 20 to connect the utilization-side heat exchanger 19 to the refrigerant and water circuits described above penetrate the walls of the sealed container, as shown in Figures 1 to 3.However, these penetration areas are also sealed, so that an uncontrolled escape of refrigerant leaks in these sealed contact areas 25 of the sealed container 20 can also be prevented. To prevent the pressure inside the sealed container 20 from increasing due to a refrigerant leak, and to prevent the uncontrolled release of the leaking flammable refrigerant into the interior space, the sealed container 20 includes a vent 23. This vent 23 allows the leaking refrigerant to be evacuated to the outside of the outer casing 15 of the indoor unit 10 in a more controlled manner. This ensures sufficient dispersion of the evacuated flammable refrigerant and prevents the risk of flammable refrigerant concentration in the interior space. It is evident from a comparison of Figures 2, 3, and 4A, 4B that the connection of the utilization-side heat exchanger 19 to the coolant circuit duct is located inside the sealed container 20, and that only the coolant circuit ducts and the water connection ducts enter / exit the sealed container 20. Therefore, the potential leak points, specifically the utilization-side heat exchanger 19, such as a plate heat exchanger, and the connection of the utilization-side heat exchanger 19 to the coolant circuit ducts, are located within the sealed container 20. In other words, the welded connections where leaks are likely to occur are located inside the sealed container 20.Consequently, the risks arising from refrigerant leakage at these connection points of the utilization-side heat exchanger 19 to the remaining part of the refrigerant circuit can be reduced, since such refrigerant leakage would simply seep into the sealed container and could then be evacuated to the outside of the outer casing 15 of the indoor unit 10 through the exhaust opening 23 in a more controlled manner. To achieve the controlled evacuation of refrigerant leakage through the exhaust opening 23, the leaking refrigerant must be evacuated to a sufficiently high point. According to the invention, for example in the embodiment shown in Figure 3, the sealed container 20 comprises a chimney 24 having a first end and a second end. The first end of the chimney 24 is in fluid communication with an interior portion of the sealed container 20, in which the utilization-side heat exchanger 19 is arranged. Conversely, the exhaust opening 23 of the sealed container 20 is arranged at the second end of the chimney. This chimney 24 is designed to increase the exhaust height of the refrigerant leakage. This provides sufficient dispersion of the leaking refrigerant within the interior space, while keeping the overall size of the indoor unit 10 small.In the example embodiment of Figures 1 to 3, chimney 24 represents a straight duct, in which the first end is a lower end of the chimney and the second end is in a higher position than the first end. Furthermore, the chimney 24 of the embodiment of Figures 1 to 3, and consequently also the exhaust opening 23 of the sealed container 20, protrudes through the top 16 of the outer casing 15 of the indoor unit 10 in a height direction to evacuate the refrigerant leak to the outside of the outer casing 15 as high as possible. Evacuating the flammable refrigerant leak as high as possible ensures sufficient dilution of the R32 leak and prevents the concentration of flammable refrigerant within the interior space. Specific requirements for the height of the exhaust opening are detailed below. In other embodiments not illustrated, it is also possible for the chimney 24 to extend horizontally, so that the first end and the second end of the chimney 24 are arranged at the same level (height). It is also possible that the chimney 24 protrudes from a side surface of the sealed container 20. This side surface represents a vertical surface of the sealed container that is arranged between the lower part 21 and the upper part 22 of the sealed container 20. In this context, the chimney 24 may comprise an "L" shape, such that a second end thereof opens in a direction that is oriented away from the base plate 11 of the indoor unit 10 and is arranged in a higher position than the first end of the chimney 24 that is in fluid communication with the interior of the sealed container 20. Such a configuration is shown as an example in the embodiment of Figure 6. Figure 6 shows a simplified cross-sectional view of the top of an indoor unit 10 similar to that described in Figures 1 to 4B. Figure 6 differs only in the shape and arrangement of the chimney 24. Consequently, the redundant description of elements similar to those in the embodiment of Figures 1 to 4B is omitted. Furthermore, it should be noted that the connection of the gaseous refrigerant pipe 17 and the water connection pipe 14 at the top of the sealed container 20 is also omitted from Figure 6 for illustrative purposes. However, with regard to the embodiment of Figure 6, it is convenient that the exhaust opening 23 of the L-shaped chimney 24 at the second end of the chimney 24 in Figure 6 is also located at a height H above the floor of the interior space, as explained above. In one particular embodiment, the exhaust opening 23 of the chimney 24 in Figure 6 is located above the top 16 of the outer casing 15. In any case, the refrigerant leakage from inside the sealed container 20 can be vented at a sufficiently high position in this embodiment. Such an arrangement provides a simple, safe, and flexible arrangement of the utilization-side heat exchanger 19 within the indoor unit 10. In another embodiment, represented by the dashed lines in Figure 6, the chimney 24 can be directed downwards, i.e., the exhaust opening 23 is oriented towards the floor.Therefore, the risk of foreign matter entering the sealed container 20 through the chimney 24 is reduced. In the embodiment shown, the exhaust opening 23 is arranged lower than the bottom 21 of the sealed container 20. However, care must be taken to ensure that the height of the exhaust opening 23 still meets the requirements described above. The cross-sectional view in Figure 7 shows another alternative embodiment of an indoor unit, which is not part of the claimed invention. This embodiment differs from the embodiments described above in the configuration of the sealed container 20 and the exhaust opening 23, and does not require a chimney. However, the description of elements similar to those in the embodiments described above will be omitted. The exhaust opening 23 of the embodiment of Figure 7 is arranged in the upper part 22 of the sealed container 20. In addition, the sealed container 20 protrudes through the upper part 16 of the outer casing 15 of the indoor unit 10. An additional embodiment, which is not part of the claimed invention, is shown in the partial cross-sectional view of the indoor unit 10 in Figure 8. In this embodiment, the utilization-side heat exchanger 19, which is housed in the sealed container 20, and all corresponding water and refrigerant lines, such as the gaseous refrigerant line 17, the liquid refrigerant line 18, as well as the water connection lines 14, enter and exit the sealed container 20 through the exhaust opening 23. An arrangement of the ducts entering and exiting the sealed container 20 through the exhaust opening 23 avoids sealed contact areas 25, for example, on the side walls of the sealed container 20, through which leaking refrigerant could potentially escape uncontrollably from the sealed container 20. Consequently, the safety of the indoor unit 10 can be improved. It should be noted that this arrangement works with all the embodiments described above, i.e., those having a chimney 24 and those having an exhaust opening 23 at the top 22 of the sealed container 20 that protrudes from the top 16 of the indoor unit 10. Regardless of the actual configuration and arrangement of the sealed container 20, the chimney 24, the exhaust opening 23 or similar, it is emphasized once again that it is important to position the exhaust opening 23 of the sealed container 20 as high as possible above the floor of the interior space, when the outer casing of the indoor unit is installed therein. This allows any flammable refrigerant that escapes from the utilization-side heat exchanger 19, or from its connection points, to the remaining elements of the refrigerant circuit arranged in the outdoor unit, to accumulate mainly within the sealed container 20. If the amount of refrigerant leakage increases and the sealed container fills up, the refrigerant leakage can be evacuated to the outside of the indoor unit 10 and into the indoor space in a high position through the exhaust opening 23. Since the flammable refrigerant used in the embodiments described above has a higher density than air at atmospheric pressure, the flammable refrigerant will accumulate in the lower part of the interior space. This can lead to a dangerous concentration of flammable refrigerant within the interior space, which, in the worst-case scenario, could cause a fire. Consequently, all the implementations described above are fundamentally aimed at containing all potential refrigerant leak points within the sealed container. This allows the height at which the refrigerant is released from the sealed container to be reliably determined and adjusted as needed, particularly by appropriately positioning the exhaust opening. Specifically, the refrigerant can be evacuated to ensure sufficient dilution within the internal space. This reduces the risk of a flammable refrigerant concentration within the internal space. Having an exhaust opening 23 at one end of a chimney 24 allows for the dispersion of the refrigerant due to the sufficient height of the exhaust opening. In this respect, all described embodiments of the invention relate to refrigeration systems with improved airtightness and evacuate the flammable refrigerant through the exhaust opening 23 to a height of at least 1.8 m above the floor of the interior space in which the indoor unit is located. The height H of the exhaust opening is highlighted in Figure 2 for illustrative purposes. Consequently, ventilation or similar measures are not required, even in small interior spaces (such as, for example, houses) with a total floor area of 200 m² or less. However, arrangements with a lower exhaust height through the exhaust opening 23 are also applicable.In this context, it is possible to position the escape height of the flammable refrigerant leaking through the exhaust opening 23 below 1.8 m from the floor of the interior space where the indoor unit is located. However, such configurations may require additional measures to ensure safe handling in the event of a leak. Examples of such measures include a fan that increases the mixing of the leaking refrigerant with the available air volume in the interior space, or even an active ventilation system that exchanges the air in the interior space. The fan can run continuously, or it can be activated upon detecting a refrigerant leak. This ensures sufficient dispersion of the leaking flammable refrigerant in the intermediate space. Other possible applications include alarm functions or evacuating the refrigerant from the refrigerant circuit to a location within the circuit where it can be safely stored, such as an outdoor unit of the heat pump. For cooling systems without improved sealing, the height of the exhaust opening 23 must be equal to or greater than the larger result of the following formulas: H reflects the minimum height of the exhaust opening 23 measured from the floor of the interior space, mc reflects a mass of refrigerant in the refrigerant circuit, LFL reflects a lower flammability limit of the refrigerant used, SF reflects a safety factor, and A represents the area of the interior space. The lower flammability limit of R32 can be considered, for example, as LFL = 0.307, the safety factor as SF = 0.75, and the area of the interior space as A = 200 m². Inserting the above values of SF = 0.75 and A = 200 m2 into the above formulas yields the following formulas: However, other values for the interior space area A, the safety factor SF, etc., are also applicable. The height H of the escape opening has been highlighted in Figure 2 for guidance purposes. When installing a floor-standing indoor unit, the height can be measured from the floor of the interior space in direct contact with the unit's base plate or stand. However, other installation methods are also applicable, such as mounting the indoor unit on a shelf or platform. In these cases, the exhaust opening height is not measured from the platform in contact with the indoor unit, but rather from the floor of the interior space in contact with the platform. Even when multiple elements are located between the indoor unit (including the exhaust opening) and the floor of the interior space, the exhaust opening height is measured from the floor of the interior space to the exhaust opening of the sealed enclosure, regardless of the number of intervening elements.In any case, for cooling systems without improved sealing, the minimum height of the exhaust opening with respect to the lower surface (floor) of the interior space must be 0.6 m. List of references 10 indoor unit 11 insulated tank 12 motherboard 13 drain tray 14 water connection conduit 15 outer casing 16. Top of the outer casing 17 gaseous refrigerant conduit 18 liquid coolant conduit 19 utilization-side heat exchanger 20 sealed container 21 bottom of the sealed container 22 top of the sealed container 23 exhaust opening 24 fireplace 25 sealed contact area 26 domestic hot water pipe 27 freshwater conduit 28 sealed container side walls 29 casing 30 lid 31 sealed
Claims
1. A heat pump, comprising: a refrigerant circuit configured to circulate a flammable refrigerant, the refrigerant circuit having a compressor, a utilization-side heat exchanger (19), an expansion device, and a heat source-side heat exchanger connected by ducts; and an indoor unit (10) configured to be arranged in an indoor space, comprising: an outer casing (15) having a top portion (16); a sealed container (20) housed in the outer casing (15), wherein the sealed container (20) has a bottom portion (21) and a top portion (22) and houses at least one of the following: the compressor, the utilization-side heat exchanger (19), the expansion device, and the heat source-side heat exchanger,wherein the sealed container (20) has an exhaust opening (23) adapted to evacuate a refrigerant leak to the outside of the outer casing (15) of the indoor unit (10), characterized in that the sealed container (20) comprises a chimney (24) adapted to evacuate a refrigerant leak to the interior space, the chimney (24) having a first end and a second end, wherein the first end of the chimney (24) is in fluid communication with an interior portion of the sealed container (20), and the exhaust opening (23) of the sealed container (20) is arranged at the second end of the chimney (24).
2. Heat pump according to claim 1, wherein the exhaust opening (23) is located further from the bottom (21) than from the top (22) of the sealed container (20) to evacuate the refrigerant leak to the interior space.
3. Heat pump according to claim 2,wherein the exhaust opening (23) is located above the top (16) of the outer casing (15).
4. Heat pump according to any of the preceding claims, wherein the utilization-side heat exchanger (19) is housed in the sealed container (20).
5. Heat pump according to any of the preceding claims, wherein a connection of at least one of the compressor, the utilization-side heat exchanger (19), the expansion device, and the heat source-side heat exchanger, which is / are housed in the sealed container (20), to the ductwork is housed in the sealed container (20).
6. Heat pump according to any of claims 1 to 5, wherein a) the exhaust opening (23) is located at least 1.8 m above the floor of the interior space,when the outer casing (15) of the indoor unit (10) is installed, and (ob) the exhaust opening (23) is located below 1.8 m with respect to the floor of the interior space, when the outer casing (15) of the indoor unit (10) is installed and a fan is arranged to at least circulate air in the interior space.
7. Heat pump according to any of claims 1 to 5, wherein the exhaust opening (23) is located at a height above the floor of the interior space, when the outer casing (15) of the indoor unit (10) is installed, which is equal to or greater than the larger result of the following formulas: where H reflects the minimum height of the exhaust opening (23) measured from the floor of the interior space, mc reflects a mass of the refrigerant in the refrigerant circuit, and LFL reflects a low flammability level coefficient.
8. Heat pump according to any of the preceding claims,wherein the cumulative area in the sealed container (20) of all openings, other than the exhaust opening (23), having a single dimension greater than 0.1 mm and communicating the interior of the sealed container (20) with an environment outside the sealed container (20), is less than 5 cm², wherein openings located in the sealed container (20), other than the exhaust opening (23), having a single dimension of no more than 0.1 mm are not considered openings through which refrigerant leakage may occur.
9. Heat pump according to any of the preceding claims, wherein the conduits connecting to at least one of the following, the compressor, the utilization-side heat exchanger (19), the expansion device, and the heat source-side heat exchanger, which is / are housed in the sealed container (20),pass through the exhaust opening (23) to connect to the rest of the refrigerant circuit.
10. Heat pump according to any of the preceding claims, wherein the refrigerant circuit contains the flammable refrigerant, and / or wherein the refrigerant consists of or comprises R32.
11. Method for installing a heat pump according to any of claims 1 to 5 above, comprising the following step: installing the outer casing (15) of the indoor unit (10) of the heat pump in the interior space, wherein the exhaust opening (23) of the sealed container (20) is arranged at least 1.8 m above the floor of the interior space.
12. Method for installing a heat pump according to any of claims 1 to 5 above, comprising the following step: installing the outer casing (15) of the indoor unit (10) of the heat pump in the interior space,wherein a fan is disposed in the interior space to at least circulate air in the interior space, and wherein the exhaust opening (23) of the sealed container (20) is disposed below 1.8 m with respect to the floor of the interior space.
13. Method for installing a heat pump according to any of claims 1 to 5 above, comprising the following step: installing the outer casing (15) of the indoor unit (10) of the heat pump in the interior space, wherein the exhaust opening (23) of the sealed container (20) is disposed at a height above the floor of the interior space, when the outer casing (15) of the indoor unit (10) is installed, which is equal to or greater than the greater of the following formulas: wherein H reflects the minimum height of the exhaust opening (23) measured from the floor of the interior space, mc reflects a mass of the refrigerant in the refrigerant circuit,LFL reflects a lower flammability limit, SF reflects a safety factor, where SF is 0.75, and A represents the area of the interior space, where A is preferably 200 m2.