Dishwasher having a heat-pump arrangement, and heat-transfer device for same

Abstract

The invention relates to a heat-pump arrangement (14) for a dishwasher (1), to which heat-pump arrangement a heat-transfer device (WT) is assigned in which rinsing fluid (24) to be heated flows through at least one pipe portion (28) and is guided outwards to the inner wall (28a) of the pipe portion (28) by a guide means (29). The pipe portion is in heat-exchanging contact with the condenser (18) of the heat-pump arrangement. The working medium (17) of the heat-pump arrangement flows helically around the outside of the pipe portion (28) as an external medium.

Description

[0001] Dishwasher with a heat pump arrangement, and heat transfer device for this

[0002] The present invention relates to a dishwasher, in particular a household dishwasher, having a heat pump arrangement which comprises at least one compressor, a condenser, an expansion element and an evaporator, which are connected to one another via line sections for conveying a working medium which changes its state of aggregation during operation of the heat pump arrangement, wherein the heat pump arrangement is assigned a heat transfer device by means of which, during operation of the heat pump arrangement, heat can be transferred from the working medium flowing through the condenser to washing liquid, in particular circulating or circulating in the dishwasher, in order to heat the latter.

[0003] In order to optimise the energy consumption of dishwashers, in particular household dishwashers, these can be equipped with heat pumps or heat pump arrangements in order to at least support the heating of rinsing liquid or rinsing water, in particular circulating rinsing water, and in particular to achieve this completely via the heat pump. However, in practice it is difficult and / or complex to arrange the components of the heat pump, such as its compressor, condenser, expansion element and evaporator, as well as the line sections connecting these to one another to form a circuit in the dishwasher, in very confined spaces, in particular in the base area of ​​the dishwasher below its rinsing container. The components of the heat pump or heat pump arrangement should therefore be kept as compact as possible.On the other hand, for the heat pump to function efficiently, it is essential that, during operation of the heat pump—i.e., when the compressor is running or driven—there is good heat exchange between the evaporator (or, associated with this, between the heat pump's working fluid flowing through it) and the ambient air (or another heat-emitting medium), as well as between the condenser (or, associated with this, between the heat pump's working fluid flowing through it) and the flushing fluid to be heated. This prevents the evaporator and / or condenser of the heat pump from becoming arbitrarily small.

[0004] Preferably, items to be cleaned in the washing chamber of the dishwasher are subjected to the washing liquid that is heated in a supportive or complete manner by means of the heat pump in at least one washing phase, such as the cleaning phase and / or the final rinse phase of a dishwashing program to be carried out, by means of one or more liquid application units provided in the washing chamber, such as by means of rotatable spray arms, fixed or movable, in particular rotatable, nozzles and / or by means of other liquid dispensing devices.

[0005] The invention is based on the problem of being able to realize a heat transfer device that is as compact as possible in a heat pump arrangement for a dishwasher, in particular a household dishwasher, by means of which heat can be transferred from the working medium flowing through the condenser to the washing liquid or washing water in order to heat it or the latter in the most energy-efficient way possible.

[0006] The invention solves this problem by a dishwasher, in particular a household dishwasher, having the features of claim 1 and by a heat transfer device having the features of claim 28. With regard to advantageous embodiments and further developments of the invention, reference is made to the further claims 2 to 27.

[0007] Because the dishwasher, especially

[0008] In a household dishwasher of the type mentioned at the outset, according to the invention the heat transfer device is designed such that the washing liquid to be heated flows through at least one pipe section or pipe section and is guided as an inner medium flowing through this by means of a guide aid to the inside wall of the pipe section, which is in heat exchange contact with the condenser, in which the working medium flows around the outside of the pipe section in a spiral shape as an outer medium, a compact unit for energy-effective or energy-efficient heat transfer is provided between the working medium flowing through the condenser (in particular during operation of the heat pump arrangement) and the washing liquid flowing through the pipe section for its heating.

[0009] By assigning at least one pipe section to the condenser for the heat transfer from the working medium to the rinsing liquid, in which pipe section the rinsing liquid to be heated can be guided as an internal medium flowing through it by means of a guide aid outwards, in particular with a radial directional component outwards, to the inner wall of the pipe section, i.e. viewed in cross section from the center of the pipe section outwards, in particular with a radial directional component outwards, to the radially outer edge of the flow or through-flow channel of the pipe section, which is in heat exchange contact with the condenser on the outside, in which the working medium of the heat pump flows spirally around the pipe section along its longitudinal extent as an external medium, the free cross section of the path for the internal medium, i.e.for the flushing fluid, through the pipe section is reduced compared to a pipe section without a guide aid, so that this internal medium must flow through the pipe section equipped with the guide aid at a higher speed than in a pipe section without a guide aid, even at the same volume flow. The guide aid provided in the pipe section creates a flow channel for the flushing fluid in the pipe section leading from its inlet end to its outlet end, the flow cross-section of which is reduced compared to the full flow cross-section of the pipe section if no guide aid is provided in the pipe section.The reduction in the pipe section's flow cross-section, brought about by the guide aid, increases the flow velocity of the flushing liquid and thus its ability to transfer heat from the radially outer inner wall of the pipe section against which it flows. This wall is heated by the condenser arranged around the outside of the pipe section, in which the working medium flows spirally around the outside of the pipe section. This results in an improved transfer of heat from the outer medium, i.e. from the working medium of the heat pump, to the inner medium, i.e. to the flushing liquid. In other words, heat (thermal energy) can be transferred from the working medium flowing through the condenser to the flushing liquid in an improved or more energy-efficient manner. In addition, because the inner medium is directed outwards to the radial edge, i.e.The inner wall of the pipe section is routed through, i.e., the inner wall of the pipe section, and the external medium flowing or running through the condenser outside the pipe section is very close, which further promotes heat transfer from the working medium to the flushing liquid. The installation space for the heat transfer device, which comprises the heat transfer section of the heat pump's condenser through which the working medium flows or can flow, and the pipe section or pipe section thermally coupled to it, through which the flushing liquid to be heated flows or can flow, can be significantly reduced through these two improvements for heat transfer from the working medium to the flushing liquid.In particular, even a short axial length of this heat transfer device can be sufficient for energy-efficient transfer of heat from the working medium flowing in the condenser (- during operation of the heat pump arrangement -) to the flushing liquid flowing in the pipe section to heat it.

[0010] The pipe section through which the flushing liquid flows or through which it flows for heating is preferably arranged in or within the condenser. It can be particularly advantageous if the outer casing of the pipe section, which is in particular circular-cylindrical in shape, is wound on the outside in a helical or spiral manner with a heat-dissipating line section of the condenser, in particular a condenser tube. Preferably, two adjacent turns of the condenser line section, in particular of the condenser tube, along the axial length of the pipe section are located close to one another; in particular, they are in contact with one another.Due to the high winding density of the condenser line section, in particular the condenser tube, which is ensured in this way, this, in particular this, provides a sufficiently high thermal output density on the outer jacket of the pipe section in relation to its predetermined axial length, which is limited in particular by the limited space in the base area of ​​the dishwasher, which is necessary to heat the washing liquid to a desired target temperature within a predetermined period of time.

[0011] It can be particularly advantageous if the guide aid forces the inner medium, i.e. the flushing liquid to be heated, into at least one spiral path or helix, which preferably moves along the radially outer edge of the flow channel provided in the pipe section and thus along the inner wall of the pipe section along its axial length. This spiral path or helix increases the path that the flushing liquid has to take through the pipe section (from its inlet end to its outlet end), preferably by a multiple (compared to a merely, i.e.exclusively, along the axial, in particular at least approximately rectilinear, longitudinal extent of the pipe section, preferably at least approximately circular-cylindrical, flow path which is present between the preferably at least approximately circular-cylindrical outer wall of the guide aid and the preferably at least approximately circular-cylindrical inner wall of the pipe section). The rinsing liquid expediently circulates the inner wall or the inner shell of the preferably at least approximately circular-cylindrical pipe section in a helical or spiral manner once or particularly preferably several times in the circumferential direction. Thus, for the same volume of rinsing liquid per unit of time, the flow rate of the rinsing liquid increases (in comparison to a merely, ieexclusively, along the axial, in particular at least approximately rectilinear, longitudinal extent of the pipe section, preferably at least approximately circular-cylindrical, flow path which is present between the preferably at least approximately circular-cylindrical outer wall of the guide aid and the preferably at least approximately circular-cylindrical inner wall of the pipe section,) continues to increase considerably, so that the ability to absorb heat (from the working medium to the rinsing liquid) increases accordingly considerably.

[0012] If the spiral path, which defines the flow path for the flushing liquid through the pipe section over its axial length, has a radial extension of 2 to 10 mm (millimeters), in particular of 2.5 mm to 8 mm, preferably of 1.5 to 4 mm (millimeters), inwards from the inner wall of the pipe section, then on the one hand the entire flushing liquid flowing in this spiral path is very close to the external working medium of the heat pump - with a corresponding improvement in the heat transfer to the flushing liquid. On the other hand, a sufficient radial height of the spiral path still remains in order to advantageously avoid turbulence and to ensure laminar flow with a high volume flow, particularly in a boundary layer to the inner casing of the pipe section.In particular, the spiral path, which defines the flow path for the flushing liquid through the pipe section over its axial length, has a total length of at least three times the axial length of the pipe section in order to be able to ensure a large flow path for the flushing liquid with the associated high speed of the flushing liquid despite only a small axial length of the pipe section and the pipe section of the condenser which spirals or winds around it on the outside.

[0013] Preferably, the spiral path, which defines the flow path for the rinsing liquid through the pipe section over its axial longitudinal extent, has a total length of at least five times the axial length of the pipe section in order to achieve a particularly large increase in the flow velocity of the rinsing liquid.

[0014] If, in particular, there are no more than six to eight turns of the spiral path, which defines the flow path for the rinsing liquid through the pipe section viewed over its axial longitudinal extent, along the axial length of the pipe section, an associated flow resistance, which counteracts the axial forward movement of the rinsing liquid, can nevertheless remain sufficiently low in order not to overload a pump which conveys the rinsing liquid through the pipe section of the heat transfer device, which pump can be formed in particular by the circulating pump of the hydraulic or circulating circuit (i.e. circulating pump circuit) of the dishwasher or by a specially provided feed pump, such as a bypass circuit branching off from the circulating circuit, and in order to prevent a drop in the volume flow of the rinsing liquid as it flows through the pipe section of the heat transfer device.

[0015] The axial length of the heat exchanger pipe section is advantageously between 10 and 30 cm (centimeters), in particular between 13 and 18 cm (centimeters), so that the installation space required for the heat transfer device, particularly in the base or base support of the dishwasher below its wash tub, is minimal. Since the rinsing fluid flows as the internal medium in the pipe section or pipe section and the working fluid of the heat pump flows as the external medium through the heat transfer pipe section of the condenser, which is only in heat exchange contact or heat conduction with the pipe section from the outside, the pipe section of the condenser does not penetrate or cross the flow channel of the pipe section through which the rinsing fluid flows.Since the entire condenser line section is located outside the interior of the pipe section through which the flushing liquid flows or can flow, the condenser does not come into contact with the flushing liquid at all. The flow channel of the pipe section through which the flushing liquid flows is thus kept clear of the condenser line section, so that no special requirements are placed on it regarding corrosion protection, resistance to flushing solutions, and / or food safety. It is particularly advantageous from a structural and thermodynamic perspective if the pipe section through which the working medium flows, in particular the tube, does not run anywhere within the flow channel of the pipe section through which the flushing liquid flows.In particular, there is no increase in the flow resistance for the flushing liquid, which would be the case if the condenser line section were partially or entirely housed within the flow channel of the flushing liquid pipe section. In this case, the inlet and outlet connections of the condenser line section would also penetrate the casing, or the inlet and outlet end closures of the flushing liquid pipe section, which would disadvantageously result in, for example, additional sealing points.

[0016] If the pipe section for the internal medium, i.e. for the rinsing liquid to be heated, is preferably made of stainless steel, high stability is achieved with easy machining and good corrosion resistance to the rinsing liquid flowing through it. The pipe section, in particular such a stainless steel pipe section, can have an (external) diameter of typically 25 - 80 mm, in particular 30 to 50 mm (millimeters) (with a negligible wall thickness such as approximately 0.8 mm of the pipe section, its internal diameter is only slightly smaller than its external diameter). In particular, from a fluidic perspective, the pipe section for the internal medium is advantageously round-symmetrical in cross-section. In spatial terms, it is preferably at least approximately cylindrical, in particular circular-cylindrical.

[0017] It may be particularly expedient, as already explained above, if a condenser line for the external medium is mounted spirally or helically on the outside of the pipe section in thermal contact with it. In particular, it can be wound helically onto the outer wall of the pipe section with such a mechanical holding force that it is held there by a radially inward-directed contact pressure. It can also be pushed onto the pipe section as a prefabricated helical spring with a radial contact pressure or clamping force.Before it is applied to the pipe section, its inner diameter is expediently smaller than the outer diameter of the pipe section, so that when pushed over the preferably at least approximately circular-cylindrical outer casing of the pipe section, it expands radially along its axial length, thereby generating a clamping force radially inward on the preferably at least approximately circular-cylindrical outer casing of the pipe section. Additionally or independently of this, the condenser line, i.e., the heat transfer line section of the condenser, can be firmly connected to the pipe section on the outside of the pipe section by means of heat-conducting solder paste, brazing solder, or adhesive.Generally speaking, it can be particularly advantageous if the heat-transfer line section of the condenser and the flushing fluid-carrying pipe section are cast, overmolded, or soldered together using a heat-conducting material. In particular, the heat-conducting material encloses a partial or entire circumference of the cylinder jacket of the heat-transfer line section of the condenser, viewed in cross-section, thus increasing its heat transfer surface to the pipe section.By means of such a thermally conductive additive, the preferably spiral-shaped line for the external medium is securely held on the pipe section and brought into thermal contact with it, thus ensuring a high degree of heat transfer from the preferably spiral-shaped line of the condenser to the pipe section through which the flushing liquid flows or through which it flows—and thus indirectly to the flushing liquid inside the pipe section. With the good heat transfer thus provided between the condenser and the pipe section, the line sections for the working medium can be formed entirely of copper or aluminum, thus avoiding problematic transitions due to foreign materials, particularly in the condenser line section.

[0018] To ensure a sufficiently large volume flow of the flushing fluid, the diameter of the pipe section for the inner medium is significantly larger than the diameter of the line for the outer medium, i.e. the heat transfer line section of the condenser through which the working medium flows (with a negligible wall thickness of the pipe section, the "diameter" corresponds approximately to the inner diameter or approximately to the outer diameter of the pipe section; with a negligible wall thickness of the condenser tube, the inner diameter of the condenser tube corresponds approximately to the outer diameter of the condenser tube). With this thin refrigerant pipe of the condenser, which is preferably wound helically or spirally around the pipe section, a particularly large condensate surface for the working medium (refrigerant) is achieved.

[0019] The spiral-shaped line for the external medium (working medium) preferably has a total winding length of 2 m (meters) to 5 m and an (inner) diameter of 3 mm to 8 mm (with a negligible wall thickness such as about 0.7 mm of the condenser tube, its outer diameter is only slightly larger than its inner diameter).

[0020] When the heat pump arrangement is switched on, the working medium flows through the spirally arranged pipe on the outside of the pipe section with a mass flow of between 2 kg / h (kilograms per hour) and 10 kg / h.

[0021] If the condenser line, which is preferably wound in a spiral shape around the pipe section through which the rinsing liquid to be heated flows or can flow, is made of copper, this is particularly advantageous. The entire working medium of the heat pump arrangement can then be conducted continuously to and from the compressor through copper lines. This facilitates the creation of the heat pump circuit. In addition, the heat pump circuit can have at least almost uniform thermal conductivity over the entire course of its lines, which facilitates its energy-efficient design and layout. In particular, a transition to other materials such as stainless steel for the heat transfer line section of the condenser is avoidable, i.e. not necessary. This is because the condenser line section does not come into contact with the rinsing liquid to be heated.Quite differently, however, a change from a copper line, preferably to a stainless steel line, for the condenser would be necessary if the condenser were located in the flow channel of the pipe section carrying the flushing liquid in order to avoid unwanted or inadmissible introduction of copper ions into the flushing liquid and / or corrosion of the condenser line.

[0022] As an alternative to copper, the lines for the working fluid of the heat pump assembly (and thus, in particular, the condenser lines) can be made entirely of aluminum. Plastic lines, for example, with a metal coating on the inside, are also possible.

[0023] Furthermore, the central line (i.e., the central zone) of the pipe section, defined by the guide aid in relation to the radial extension, can be kept free of medium flow at all times. This space can then be used for other purposes, for example, as space for a pump and / or other functional component.

[0024] Advantageously, the guide aid can be formed by a displacement body for the internal medium inserted into the pipe section. This can be subsequently inserted into the pipe section when the heat transfer device is already complete, thus making installation particularly simple.

[0025] In particular, when the displacement body blocks the inner clear width of the pipe section except for an edge gap provided with one or more guideways for a spiral flow of the flushing liquid to be heated, the aforementioned improvements in heat transfer to the flushing liquid are achieved. The spiral flow of the flushing liquid to be heated means, in particular, that in the edge gap between the centrally arranged displacement body and the pipe section arranged outside around it, it has a movement component in the circumferential direction and a movement component in the axial direction, thereby improving the heat transfer from the inner wall of the pipe section in heat exchange contact with the condenser to the flushing liquid to be heated.

[0026] In particular, it may be expedient for proper heat transfer from the inner wall of the pipe section to the flushing liquid if the volume flow of the flushing liquid through the, in particular spiral-shaped, passage gap formed between the inner wall of the pipe section and the outer wall of the displacement body is selected to be between 2 l / min and 15 l / min.

[0027] The radial center region of the pipe section advantageously remains free of washing liquid due to the displacement body accommodated there. However, one or more functional units of the dishwasher can be accommodated inside the displacement body, in particular in a liquid-tight manner. For example, the interior of the displacement body can accommodate a condensate pump, by means of which condensate can be pumped from a collecting tray arranged below the evaporator of the heat pump, e.g. into the washing container. In particular, one or more sensors, such as temperature sensors, can also be arranged inside the displacement body. If the displacement body is made of a UV-transparent material, in particular plastic, a UV light source, such asA UV light tube or a circuit board equipped with one or more UV LEDs, especially UV-C LEDs, can be housed. This allows the washing liquid flowing through the pipe section of the heat transfer device to be disinfected as needed, thus enabling the dishwasher to operate in a hygienic manner in a simple manner.

[0028] According to an advantageous development, the displacement body and the pipe section can preferably each be designed at least almost as a circular cylinder. In this case, the circular-cylindrical displacement body is advantageously surrounded at least almost concentrically on the radial outside by the circular-cylindrical pipe section with a defined radial gap spacing, so that an at least approximately circular-cylindrical edge gap or flow channel is formed between them. The rinse water to be heated forces its way through the at least approximately circular-cylindrical gap (an annular gap in cross-section) provided between the circular-cylindrical outer wall of this displacement body and the circular-cylindrical inner wall of this pipe section at a higher speed than if it were to pass through an identical pipe section without a displacement body (at the same volume flow).This promotes the heat transfer from the pipe section, whose outer shell is in heat exchange contact with the condenser, to the flushing liquid flowing through the at least almost circular-cylindrical gap space.

[0029] A further improvement in the heat transfer from the working medium flowing through the condenser to the flushing liquid to be heated, as already mentioned above, can preferably be achieved by a spiral flow of the flushing liquid through the edge gap provided between the displacement body and the pipe section surrounding it on the outside. For this purpose, according to an advantageous development, a web element is provided, in particular attached, preferably formed, on the preferably at least approximately circular-cylindrical outer wall of the displacement body, projecting outwards in the direction of the preferably at least approximately circular-cylindrical inner wall of the pipe section - preferably projecting at least almost radially outwards - which, viewed spatially, surrounds the preferably at least approximately circular-cylindrical outer shell of the displacement body along its axial longitudinal extent at least in sections, i.e.partially or particularly advantageously continuously, helically or spirally. The web element expediently projects from the preferably at least approximately circular-cylindrical outer casing of the displacement body up to the preferably at least approximately circular-cylindrical inner wall of the pipe section, i.e. it preferably reaches up to the inner wall of the pipe section and thus bridges the radial width of the edge gap. The web element subdivides the preferably annular-cylindrical edge gap present between the displacement body and the pipe section in such a way that a helical or spiral flow channel for rinsing liquid is formed. It can wind around the preferably at least approximately circular-cylindrical outer casing of the displacement body along its axial longitudinal extent, preferably with a plurality of successive turns in the axial longitudinal direction.Between the successive turns of the respective helical web element in the axial longitudinal direction, a spiral flow channel (as a guide path) is created for the flushing liquid on its axial movement path through the preferably circular-cylindrical flow channel formed between the displacement body and the pipe section, so that the flushing liquid is forced to circulate around the (inner) circumference of the pipe section on its inner wall surface during its axial movement, preferably several times, i.e. with a multitude of circuits or 360° revolutions. This improves the heat transfer from the inner shell or from the inner wall of the pipe section, the outer shell of which is in heat exchange contact with the condenser arranged around it on the outside, to the flushing liquid flowing through the spiral flow channel.

[0030] However, in order to generate a spiral flow of the flushing liquid, a single turn of the web element may be sufficient, which divides the preferably at least approximately circular edge gap between the displacement body and the pipe section into a spiral guide path for the flushing liquid.

[0031] If necessary, a plurality of web elements can also wind in a corresponding manner, each in a spiral shape, around the preferably at least approximately circular-cylindrical outer casing of the displacement body along its axial longitudinal extent, at least in sections, i.e. partially or, particularly advantageously, continuously. Between the successive windings in the axial longitudinal direction between two helical web elements arranged offset from one another in the longitudinal direction with an axial distance, a spiral-shaped flow channel (as a guide path) is produced, so that the flushing liquid, on its axial path of movement through the preferably circular-cylindrical through-channel formed between the displacement body and the pipe section, is forced to run around the circumference of the pipe section on its inner wall surface, preferably several times, i.e. with a large number of revolutions or 360° rotations.

[0032] Additionally or independently of this, one or more such helical web elements can be provided, in particular attached, to the inner wall of the heat exchanger tube section inwardly toward the outer wall of the displacement body, in particular projecting radially inward, and preferably extending to the outer shell of the displacement body. The displacement body can be made of plastic, for example, as a plastic injection-molded part, in a simple manufacturing process. The displacement body itself does not have to meet any requirements regarding thermal conduction, so no metallic material is required.

[0033] The displacement body can preferably be pressed into the pipe section to achieve a high degree of tightness. Other mounting arrangements are also possible. In this case, absolute tightness of the outwardly facing, in particular radially outwardly facing, web element of the displacement body, or of the outwardly facing, in particular radially outwardly facing webs, provided according to an advantageous variant, relative to the inner wall of the heat exchanger pipe section is not absolutely necessary.

[0034] If necessary, it is also possible for the pipe section, viewed in cross-section, to have a round symmetry shape that deviates from an advantageous circular shape, such as an oval geometric shape. Non-circular cross-sectional geometric shapes, such as a flat rectangular cross-sectional geometric shape, are also possible for the pipe section through which the rinsing liquid to be heated flows. In these modifications, too, the displacement body can expediently be arranged within the pipe section and designed with a cross-sectional geometric shape that corresponds to the cross-sectional geometric shape of the pipe section or matches it but is smaller than it, in such a way that an edge gap or flow channel with a corresponding cross-sectional geometric shape is produced between the displacement body and the pipe section.Viewed from the inside outwards, the displacement body, the edge gap, the pipe section and the line section, in particular the tube, of the condenser are thus expediently arranged at least almost concentrically to one another.

[0035] If the heat pump is assembled, filled with working fluid, and tested or tested for functionality before installation in the dishwasher, a fully functional unit is available for installation in the dishwasher, which simply needs to be connected. Filling with working fluid no longer needs to be done in the cramped and unfavorable working conditions of the dishwasher. A leak and safety test can also be completed in advance. This also allows for any resealing of the connections of the working fluid-carrying units to be carried out in advance under more ergonomic conditions. Once the heat pump is installed in the dishwasher, no further functionality testing is necessary.

[0036] If at least the essential parts of the heat pump are mechanically fixed to a supporting unit, the complete unit comprising the supporting unit and the heat pump parts arranged thereon is portable like a module and can be inserted into the dishwasher. This means that no further assembly steps are required other than attaching an electrical plug (for the electrical power supply - in particular the compressor of the heat pump arrangement -) and / or a plug for a data bus as well as a supply and discharge line for the dishwashing liquid to be heated. The unit inserted in this way can then be fixed in the dishwasher to form a permanent installation position in order to ensure it is held there securely. The supporting unit can preferably be provided by a plate-like or board-like structure, alternatively by a frame, a rack, a scaffold, or other structural structure.

[0037] Advantageously, the modular unit can also be completely removed from the dishwasher for maintenance or repair purposes, so that these tasks can also be carried out with optimized accessibility and ergonomics.

[0038] According to an advantageous development, a bypass circuit or bypass circuit can be provided, which branches off washing liquid, in particular washing liquid pumped by the circulation pump, from the hydraulic or circulation circuit (i.e., circulation pump circuit) of the dishwasher and supplies it via a supply line section to the fluid inlet of the pipe section of the heat transfer device for heating. The fluid outlet of the heat exchanger pipe section is fluidly connected to a feed point, different from the branch point and preferably downstream, for returning the washing liquid heated in the heat exchanger pipe section. At this feed point, the heated washing liquid is fed back into the hydraulic circuit of the dishwasher.In particular, the rinsing fluid heated by the heat transfer device can be fed back into the interior of the rinsing tank via a return line section of the bypass circuit connected to the fluid outlet of the heat exchanger pipe section. The proportion of rinsing fluid that passes through the bypass circuit and thus through the pipe section of the

[0039] Heat transfer device is running, can be used after an advantageous

[0040] The design variant can be switchable, in particular adjustable. In particular, the flow of flushing fluid through the bypass circuit can be opened or closed by means of a switching valve inserted into the bypass circuit, in particular into its upstream supply line before the pipe section.

[0041] The filling quantity of flushing fluid with which it fills the edge gap between the outer wall of the displacement body and the inner wall of the pipe section as it flows through is in particular smaller than in a pipe section without a central displacement body. Advantageously, a total of no more than 150 ml (milliliters), i.e. equal to or less than 150 ml, fills the edge gap, in particular the spiral flow channel, between the outer wall of the displacement body and the inner wall of the pipe section over its axial extent. The entire bypass line, comprising the heat exchanger pipe section as well as its inlet and outlet lines, can in particular only have a filling volume of 250 ml at most. This enables efficient heating of the flushing fluid as it circulates through the bypass circuit.

[0042] It can be particularly advantageous if the heat exchanger pipe section is closed off by end caps or other end closures, in particular made of plastic, towards its axial ends, i.e. in the region of its two axial ends. Each of these two end caps or end closures can expediently be provided with a further connection for flushing liquid in order to provide connections for the supply of flushing liquid to be heated into the heat exchanger pipe section and for the removal of heated flushing liquid from the heat exchanger pipe section. Preferably, the inlet-side or upstream-side closure of the heat exchanger pipe section has a connection for the supply line section (supply line) of the bypass circuit and the outlet-side orThe downstream end of the heat exchanger pipe section has a connection for the discharge line section (discharge) of the bypass circuit. Of course, it is also possible to connect the supply line to the inlet end section of the pipe section and the discharge line to the opposite, outlet end section of the pipe section in another fluid-tight manner.

[0043] Furthermore, the invention relates to the above-explained heat transfer device for the heat pump arrangement of a dishwasher, in particular a household dishwasher, and / or a heat pump arrangement with a above-explained heat transfer device for a dishwasher, in particular a household dishwasher.

[0044] Other advantageous developments and further developments of the invention are set out in the subclaims.

[0045] The advantageous embodiments and further developments of the invention explained above and / or reproduced in the subclaims can be used individually or in any combination with one another - except, for example, in cases of clear dependencies or incompatible alternatives.

[0046] The invention and its advantageous developments and further developments as well as their advantages are explained in more detail below with reference to drawings showing exemplary embodiments.

[0047] They show, in a schematic principle sketch:

[0048] Fig. 1 shows a schematic perspective view obliquely from the front of an exemplary embodiment of a household dishwasher with a downwardly pivoting door and a base or base support for receiving functional elements in the lower area, in which a heat pump or heat pump arrangement with an advantageous embodiment of a heat transfer device designed according to the principle of the invention for heating washing liquid is additionally accommodated,

[0049] Fig. 2 is a schematic, block diagram representation of the dishwasher of Figure 1 with its heat pump arrangement, which comprises an advantageous embodiment of a heat transfer device designed according to the principle of the invention between its condenser and a pipe section through which washing liquid to be heated can flow or through which it flows,

[0050] Fig. 3 is a perspective view of the heat pump arrangement of Figure 2, shown as a detail, with the heat transfer device between its condenser and the pipe section through which the rinsing liquid to be heated can flow or through which it flows,

[0051] Fig. 4 shows a detail in perspective view of the heat transfer device of the heat pump arrangement of Figure 3,

[0052] Fig. 5 shows the heat transfer device of Figure 4 in frontal view,

[0053] Fig. 6 shows a side view of the heat transfer device of Figure 4,

[0054] Fig. 7 is a section along the line VI-VI in Figure 5, and

[0055] Fig. 8 shows a section along the line VII-VII in Figure 6.

[0056] Elements with the same or comparable function and mode of operation are provided with the same reference numerals in the figures.

[0057] Figure 1 shows, by way of example, a dishwasher 1, namely a household dishwasher, without the invention being restricted thereto. If necessary, it can also be applied to another household appliance, such as a washing machine or a washer-dryer. The household dishwasher according to Figure 1 described below has, as a component of an appliance body 5 that is partially open or closed to the outside, a washing container 2 for receiving items to be washed, such as dishes, pots, cutlery, glasses, cooking utensils, and the like. The items to be washed can, for example, be arranged, in particular held, in dish baskets 11, in particular in a lower dish basket UG and in an upper dish basket OG arranged at a height above this (see Figure 2), and / or a cutlery drawer 10, and can be subjected to so-called washing liquor. The washing liquor orRinse liquid can preferably be understood as fresh water or, in particular, water circulating during operation, with or without cleaning agent and / or rinse aid and / or drying agent. The rinse liquid can also be mixed to a greater or lesser extent with soiling which is rinsed off the items to be cleaned during the one or more partial rinse cycles of a dishwashing program to be carried out. If necessary, rinse liquid can also be used for the one or more partial rinse cycles of a dishwashing program to be carried out which has been used in at least one partial rinse cycle, such as the final rinse cycle of a previous dishwashing program, but has remained relatively clean and has then been stored in a reservoir as process water. In particular, the rinse liquid can beBefore being applied to the items to be washed, the water must have passed through an ion exchanger or other water softening device. The washing container 2 can have an at least substantially rectangular floor plan with a front side V facing a user in the operating position. This front side V can form part of a kitchen front consisting of adjacent kitchen units or, in the case of a stand-alone appliance, can also be without any connection to other units.

[0058] The loading opening of the washing container 2, which in this exemplary embodiment is preferably on the front, can be closed in particular at this front side V by a (front) door or flap 3. This door 3 is shown in Figure 1 in a partially open position and then inclined to the vertical. In its final closed position, however, it stands at least almost vertically upright and, as shown in Figure 1, can be pivoted forwards and downwards in the direction of arrow 4 about a lower horizontal axis to open it, so that in the fully open position (final opening position) it is at least almost horizontal. Other movements, including via a parallelogram or other multi-joint arrangement, are also possible. Of course, a side-hinged door or an opening of the washing container 2 facing upwards can also be provided as an alternative.

[0059] On the outer and front side V of the dishwasher 1, which is vertical in the final closing position and faces the user, the door 3 can be provided with a decorative panel 6 - as here in the embodiment of Figure 1 - in order to thereby experience a visual and / or haptic enhancement and / or adaptation to surrounding kitchen furniture.

[0060] The dishwasher is designed here only as an example as a stand-alone appliance on floor B or as a so-called partially integrated appliance and is installed on floor B within a built-in niche between adjacent kitchen units below a kitchen worktop. The kitchen units and the kitchen worktop have been omitted from Figure 1 for the sake of simplicity of the drawing. In the lower area of ​​the dishwasher 1, below the washing tub 2, there can be a base or a base support 12, in particular for accommodating functional elements, such as a pump for circulating the washing liquor and / or a drain pump for suctioning the washing liquor from the pump sump PS of the washing tub 2, and also a heat pump or heat pump arrangement 14 designed according to the invention. In Figure 1, the heat pump arrangement 14 is symbolized only by a dash-dotted rectangle in the base support 12.

[0061] In the exemplary embodiment according to Figure 1, the upper region of the movable door 3 is assigned an outer panel 8 which extends in the transverse or width direction Q of the dishwasher and can comprise both displays and operating elements and then serves as the operating panel. In the region of its lower edge, as here in the exemplary embodiment of Figure 1, an access opening 7 which is accessible from the front side V for manually opening and / or closing the door 3 can expediently be provided. The access opening can in particular be integrated into the panel 8, i.e. be a component of the panel. This access opening 7 extends here, for example, only in the transverse center region in the transverse direction Q, although this is not mandatory. An access opening 7 which extends at least almost across the entire width of the household dishwasher is also possible, i.e., for a 60 cm wide household dishwasher, over 50 to 60 centimeters.

[0062] In the transverse direction Q, the dishwasher often has an extension of 45, 50 or 60 centimeters. In the depth direction from the front V to the rear, the extension is often also around 60 centimeters. These values ​​are not mandatory. Furthermore, the dishwasher 1 does not have to stand directly on a floor B as in Figure 1, but can expediently also be located on a kitchen furniture plinth or installed higher up within a kitchen unit with a height clearance from the floor B that requires less bending or no bending at all from the user when loading or unloading the lower dish basket of the dishwasher. The lower edge of the dishwasher 1 is then preferably approximately 40 to 110 centimeters above the floor B when installed or installed in this raised position relative to the floor B. The vertical height H of the dishwasher 1 can also vary depending on the installation conditions.

[0063] The washing compartment 2 is delimited all around by a total of three fixed vertical walls 13 and two horizontal walls 13 when the door or flap 3 is closed, one of which forms a ceiling (top) and another a floor (bottom) of the washing compartment 2. Adjoining the front side V facing the user in the transverse direction Q to the left are a left, at least approximately vertically upright side wall 13 and to the right are a right, at least approximately vertically upright side wall 13, each of which extends at least almost over the vertical height H of the dishwasher 1. They are connected to one another at the rear by an at least almost vertically upright rear wall 13.

[0064] In the washing chamber of the washing container 2, one or more liquid application units, in particular spray devices such as, in this exemplary embodiment, a lower rotating spray arm US assigned to the lower dish basket UG, an upper rotating spray arm OS assigned to the upper dish basket OG, and, above the upper cutlery drawer 10, a roof sprayer or a rotating roof gyroscope DK in the area of ​​the ceiling wall of the washing container, are provided (see Figure 2). These liquid application units are supplied with washing liquid via one or more supply lines such as ZL1, ZL2.For this purpose, a circulation pump UP sucks in rinsing liquid from a pump sump PS or liquid collection area which is fluidically connected to the rinsing chamber of the rinsing container 2, and this rinsing liquid is distributed optionally to the supply lines leading to the liquid application units via a water switch which is preferably integrated into the circulation pump UP or, as here in the exemplary embodiment of Figure 2, via a water switch WS which is fluidically arranged downstream of the circulation pump UP in its conveying direction, ie it is pumped simultaneously only into the supply line of a liquid application unit which is to be operated individually or selectively, or into the supply lines leading to at least one desired combination of several liquid application units which are to be operated simultaneously.In the embodiment of Figure 2, for example, rinsing liquid is pumped to the lower, rotatable spray arm US via the supply line ZL1 when the water diverter WS is set to a corresponding, first position and the circulation pump UP is running. The upper, rotatable spray arm OS as well as the roof shower or the rotatable roof rotor DK are jointly supplied with rinsing liquid via the shared supply line ZL2 when the water diverter WS is set to a corresponding, second position and the circulation pump UP is running. Of course, it is also possible to deviate from this and supply the upper, rotatable spray arm OS as well as the roof shower or the rotatable roof rotor DK with rinsing liquid via their own supply line via the water diverter WS. If other or further liquid application units are provided in the dishwashing chamber, separate or dedicated supply lines can also run to these from the water diverter WS or, if necessary,At least a subgroup of these liquid supply units is supplied with rinsing liquid via a common supply line starting from the water switch WS.

[0065] According to the embodiment of Figure 2, the pump sump PS is arranged below an outflow opening provided in the bottom wall of the rinsing tank 2 and is fluidly connected thereto. This outflow opening and / or the pump sump can be provided with a filter system, which has been omitted in Figure 2 for the sake of simplicity.

[0066] In this way, the wash chamber of the wash tank 2, the pump sump PS, the circulation pump UP, the water diverter WS, the one or more supply lines or liquid distribution lines such as ZL1, ZL2, as well as the one or more liquid supply units arranged in the wash chamber of the wash tank 2, such as US, OS, DK, form a liquid circulation circuit (i.e., circulation pump circuit) or hydraulic circuit HK for supplying the washware in the wash chamber with wash liquid. The circulation pump UP is in operation when the washware in the wash chamber is to be supplied with wash liquid.

[0067] The dishwasher 1 is equipped with at least one heat pump or heat pump arrangement, which is designated overall by the reference numeral 14 and is shown only roughly schematically in Figure 2 in an exemplary embodiment. With its aid, the washing liquid present in the circulating pump circuit or hydraulic circuit HK is to be heated to a desired target final temperature during at least one liquid-carrying partial washing phase, such as the cleaning phase and / or final rinse phase of a dishwashing program to be carried out. In this exemplary embodiment, the heat pump 14 is in particular a compressor pump, i.e., it comprises a compressor or compressor 16, with which mechanical work can be performed on a working medium 17, for example a propane / butane mixture, circulating in the heat pump 14. The compressor 16, in which the mechanical work on the working medium 17 is performed, is electrically driven.

[0068] In addition to the compressor 16, the heat pump or heat pump assembly 14 comprises at least one condenser 18, an expansion device or expansion element 19, for example, an expansion valve or a capillary 36, and an evaporator 20. These functional units 16, 18, 19, 20 are interconnected via line regions or line sections 21 for conveying a working medium 17 that changes state of aggregation during operation. A dryer cartridge TP can expediently be inserted into the line section between the condenser 18 and the expansion device 19, as shown in the exemplary embodiment of Figure 2. The working medium 17 flowing through the heat pump assembly 14 during its operation (compressor 16 is switched on) is symbolized in Figure 2 by a separately shown arrow, which also indicates its flow direction.In addition to the components mentioned, the heat pump arrangement 14 expediently comprises at least one air conveying device 39 which is assigned to the evaporator 20. The air conveying device 39, in particular a fan, ensures that ambient air is blown along the line regions or line sections of the evaporator 20 through which the working medium 17 can flow or through and / or along fins which are thermally conductively connected to these and protrude from these, whereby heat is extracted from the ambient air and transferred to the working medium 17. The air conveying device 39 is expediently arranged in this embodiment such that, during its ongoing operation, ambient air from the space surrounding the dishwasher 1 is drawn in through front ventilation slots and / or through gaps, cracks, recesses and / or openings in the one or more walls of the base support orthrough the base of the dishwasher and is preferably blown backwards (in the depth direction of the dishwasher) to the evaporator 20 and flows along one or more, preferably meandering, line regions or line sections through which the working medium can flow or through and / or along the fins projecting from these. Viewed in the conveying direction of the air conveying device 39, after it has passed through the evaporator 20, ie through the gaps between the line regions of the evaporator 20 and / or between the fins thermally conductively connected to them and projecting from them, the ambient air cooled by the evaporator 20 can preferably escape through a recess or opening in the rear wall R of the dishwasher 1 to the outside into the environment of the dishwasher.

[0069] The heat pump 14 is also assigned at least one supply line 22 and one discharge line 23 for rinsing liquid 24 that can be or is circulating in the household appliance, as well as an electrical connection option 25. By means of the electrical connection option 25, the compressor 16 can be supplied with electrical energy for its operation and / or the air conveying device 39 for its operation.

[0070] The supply line 22 branches off flushing liquid 24 from the circulation circuit or circulation pump circuit HK into a bypass circuit BK which runs parallel to this in terms of fluid flow and guides it there through a heat transfer line section or pipe section 28 which is in thermal contact with the condenser 18. The condenser 18 and the heat transfer line section or pipe section 28 through which the flushing liquid flows or (when the circulation pump UP is switched on) through which it flows together form a heat exchanger or heat transfer device WT in which, during ongoing operation of the heat pump 14 (when the compressor 16 is switched on), heat is transferred from the working medium 17 to the flushing liquid 24 flowing through the heat transfer section or pipe section 28, in particular pumped by means of the circulation pump UP.From the outlet of pipe section 28, the rinsing liquid 24 heated by the condenser 18 is returned via the discharge line 23 directly into the rinsing tank 2 or to another point in the circulation circuit HK. In particular, it can be advantageous if the discharge line 23 opens into the circulation circuit UK at a point which, viewed in the direction of flow, lies upstream of the circulation pump UP, i.e. on its suction side. It can be particularly advantageous if the supply line 22 - as schematically indicated in Figure 2 - branches off from the internal liquid conveying channel of the circulation pump UP (viewed in the direction of flow), preferably immediately behind its impeller chamber and thus on the pressure side, preferably upstream of its downstream diffuser chamber, via a specially provided outlet opening as a bypass line. A valve VA can expediently be inserted into this supply line 22 - as here in the embodiment of Figure 2.With its help, the flow of rinsing liquid caused by the circulation pump UP during pumping operation can be enabled or disabled through the supply line 22 to the pipe section 28, i.e. the bypass circuit BK can be opened or closed. The rinsing liquid 24 flowing through the circulation circuit or circulation pump circuit HK and through the bypass circuit BK is symbolized in Figure 2 by separately shown arrows, which also indicate the direction of flow of the rinsing liquid in the circulation circuit (i.e. circulation pump circuit) HK serving to distribute rinsing liquid in the dishwashing chamber, as well as in the bypass circuit BK, which comprises the heat transfer device WT with the thermal coupling between the condenser 18 and the heat transfer line section or pipe section 28 carrying the rinsing liquid for heating the rinsing liquid by means of the heat pump 14.

[0071] In particular, it may be expedient to close the valve VA and thus block the supply of rinsing liquid 24 from the circulation pump circuit HK into the bypass circuit BK when no heating of the rinsing liquid (in particular higher than its inlet temperature) is required. This may be the case, for example, during a pre-rinse phase or an intermediate rinse phase of a dishwashing program, during which unheated fresh water, preferably from the building water supply, and / or domestic water at ambient temperature, preferably from a storage tank, may suffice. By closing the valve VA, the amount of rinsing liquid that would otherwise flow through the bypass circuit BK can be saved.

[0072] In addition to the electrical connection option 25 and the connection option 22, 23 for the rinsing fluid 24, the heat pump assembly 14 may optionally include various sensors and a connection for a communication interface, in particular for a data bus—both of which are not shown. The electrical connection 25 may—as shown by way of example in Figure 3—in particular be part of an electrical module 37, which may also include sensors and the communication interface connection, in particular the data bus connection.

[0073] As an alternative to the branching point in the circulation pump UP, the bypass circuit BK can branch off with its supply line 22 from a different point in the circulation circuit HK, in particular on the pressure side after the circulation pump UP (viewed in the conveying direction of the circulation circuit UK determined by the circulation pump UP).

[0074] In particular, it may be expedient if the circulation pump UP, with the water diverter WS set accordingly, pumps the washing liquid 24 through the circulation circuit HK to one or more washing liquid supply units and, simultaneously, i.e., simultaneously, a portion of the washing liquid 24 through the bypass circuit BK for heating. This operating mode allows the desired dishwashing program to be carried out in an energy-efficient manner within its specified program runtime.

[0075] If necessary, a specially provided feed pump can also be integrated into the bypass circuit BK (this has been omitted from Figure 2 for the sake of clarity). When this is switched on, the dishwashing liquid can circulate through the bypass circuit BK to be heated by means of the heat transfer device WT, without the circulation pump UP having to be switched on. When the circulation pump UP is switched off and the specially provided feed pump in the bypass circuit BK is switched on, dishwashing liquid only circulates through the bypass circuit BK and not through the circulation pump circuit HK. This can be beneficial for the energy efficiency of a dishwashing program being carried out, since preferably a smaller quantity of dishwashing liquid to be heated is circulated in the bypass circuit than in the circulation circuit, via which the dishwashing liquid is distributed, in particular sprayed, in the dishwashing chamber by means of one or more liquid application units.

[0076] In the heat exchanger WT, the flushing fluid 24 to be heated passes through the heat transfer line section or pipe section 28 in a countercurrent flow to the working medium 17 flowing through the condenser 18. This ensures efficient, ie, highly effective, transfer of heat from the working medium 17 to the flushing fluid 24 in the heat exchanger WT.

[0077] This heat pump 14, in particular its essential components such as 16, 18, 19, 20, 21 and possibly 39, can, as schematically shown in Figure 2, form a modular unit 26 and, before installation in the dishwasher 1, can be pre-assembled, filled with working medium 17 and either testable for function or, in particular, already tested for function before installation. This test is expediently accompanied by a leak test so that any leakage of working medium 17, for example a propane / butane mixture, is prevented. A filling connection BA for the working medium 17 of the heat pump arrangement 14, which, as shown in Figure 3, can be provided on the compressor 16, for example, can therefore be tightly squeezed shut after filling with working medium 17 before installation of the heat pump arrangement 14 in the dishwasher 1.In particular, the line sections 21 through which the working medium 17 can flow and their connections to the essential functional units 16, 18, 19, 20 of the heat pump 14 are tested. The line sections 21 for the working medium 17 can preferably be made entirely of copper or, alternatively, entirely of aluminum. Plastic lines, for example with a metal coating on the inside, are also possible as line sections 21. To form a modular unit 26, the entire heat pump arrangement 14 can be held or fixed to a common support 15. Figure 3 illustrates, in a perspective view, an advantageous embodiment of this compact modular unit 26, in which the essential components such as 16, 18, 19, 20, 21 and optionally 39 of the heat pump arrangement 14 are firmly attached to a support plate that is preferably at least approximately flat.In particular, at least the essential components of the heat pump arrangement 14, such as the compressor 16, the heat exchanger WT, which has the condenser 18 and the pipe section 28 thermally coupled to the latter and through which washing liquid to be heated can flow or flows, the expansion device 19, the evaporator 20, optionally the fan associated with the evaporator, and the lines 21 connecting these components to form a heat pump circuit for the working medium 17, can be arranged in a mechanically fixed manner on the carrier unit 15 holding them. This does not necessarily have to be accompanied by the aforementioned pre-assembly and filling with working medium 17 as well as the leak test outside the dishwasher 1. However, it is advisable to combine the two.The valve VA, the supply line 22, and / or the discharge line 23 of the bypass circuit BK can, but do not have to, be part of the pre-assembled heat pump assembly 14, but can also be connected to the hydraulic circuit HK only after the heat pump assembly 14 has been inserted into the dishwasher - preferably into the base support of the dishwasher - during manufacture of the dishwasher. Similarly, the electrical line EL for the electrical connection 25 and / or the communication line (not shown) for the communication connection can not be part of the pre-assembled heat pump assembly 14, but can also be connected to the electrical connection module 25 only after the heat pump assembly 14 has been inserted into the dishwasher - preferably into the base support of the dishwasher - during manufacture of the dishwasher.

[0078] As an alternative to the embodiment of Figure 3, in which the support unit 15 is formed by an at least approximately flat or board-like support plate, it can also be provided by a frame, a rack, a scaffold, or another structural structure. In particular, this allows the weight of the support unit to be reduced. Further units associated with the components of the heat pump arrangement 14 can also be provided, in particular fastened or mounted, on, or in particular on this support 15, such as a support frame, rack, scaffold, or structural structure, or on a support plate—preferably at least approximately flat, as shown in Figure 3. Thus, according to Figure 2, an optional condensate collection tray AW is mechanically fixedly attached to the support 15, in particular to a support plate, below the evaporator 20. In particular, it can be integrally formed on the support 15, in particular to the support plate.This is particularly advantageous if the carrier 15, in particular the carrier plate, is made of a plastic material, for example.

[0079] Depending on its design, the condensate collecting tray AW can also be located below the support or support unit 15. If necessary, it can also be a component of the base support 12, in particular its bottom wall. In particular, it can be molded onto it. This is advantageous if the structure of the base support 12 is made of plastic material. The support unit 15, in particular the support plate, then expediently ends before the drip area of ​​the evaporator 20, i.e. above the condensate collecting tray AW, the support unit 15, in particular the support plate, is missing below the drip area of ​​the evaporator 20, or it is cut out there or has a recess there so that the condensate forming on the evaporator 20 during operation of the heat pump 14 can drip down into the condensate collecting tray AW.Condensate accumulating in the area of ​​the evaporator 20 during operation of the heat pump arrangement 14 and collected in the condensate collection tray AW below it can be returned to the rinsing tank 2, for example, via a condensate pump KP and a liquid line (return line) KL connected to it, or via a condensate pump inserted into the return line KL. The condensate pump KP can be mechanically fixedly mounted in the condensate collection tray AW or outside of it on the support unit 15, in particular on the support plate, or at a location in the base support 12.

[0080] In the arrangement with the mechanically fixed components 16, 18, 19, 20, and possibly 39 of the heat pump 14, together with the support unit 15 holding it, a modular unit 26 is created which can be inserted into a permanent installation position in the dishwasher 1 by hand and / or by robot. In the exemplary embodiment of Figure 3, the support unit 15 comprises a plate 27 which lies horizontally in the installed position. Alternatively, a vertical support unit 15 is also possible. A vertical support with a base plate or other shapes are also possible. The entire unit 26 typically weighs approximately 3 to 10 kg (kilograms), in particular around 6 kilograms. Viewed in plan view, its edge length is preferably approximately 50 centimeters from the electrical module 37 to the evaporator 20 and approximately 25 centimeters transversely thereto. Thus, when the support unit 15 is installed horizontally, preferably approximatelyone third to one half of the base area of ​​the dishwasher 1 is occupied by the modular unit 26.

[0081] The support unit 15 can be made of plastic, for example. A metal construction, such as aluminum or steel, is also possible.

[0082] In addition to simplifying installation, the modular unit 26 can be completely removed from the dishwasher 1 for maintenance or repair purposes. This allows the removed modular unit 26 to be repaired in an ergonomically favorable posture. A complete replacement of the modular unit 26 with a new or repaired unit is also possible.

[0083] The support unit 15 does not have to form a plate-like body, but can - as already stated above - also be designed as a frame unit, rack, scaffold, or structural structure. In both cases, a particularly simple option in terms of design and materials is provided if the support unit 15 is formed in one piece. However, it can also be formed in several parts and, in particular, also have recesses, cutouts, or similar adaptations to space and holding devices in the dishwasher 1. A strict rectangular shape, as shown here in the exemplary embodiment, is therefore not required. For example, an L-shaped design in plan view would also be possible with a different arrangement of the components of the heat pump 14.

[0084] Very advantageously (not shown here) the support unit 15 is pre-assembled with several mechanical attachment aids for attaching or attaching the components 16, 18, 19, 20, 21, and possibly 39 of the heat pump 14. Such attachment aids can have various mechanical designs and, for example, each include screw threads, clamping elements such as spring clips, and / or snap elements, plug-in elements, etc. ... for firmly holding the aforementioned components.

[0085] Overall, the carrier unit 15 with the heat pump 14 mounted thereon forms a mechanically stable unit 26 that is portable as a whole for installation in the dishwasher 1. This unit can also be transported between different plants or production sites or different production lines.

[0086] At the upper end of the compressor 16, a holding attachment HA is provided for an assembly tool such as a robot arm (not shown) as an assembly aid, which, in particular for installing the modular unit 26, carries a significant part of the weight of the unit 26, so that an assembling worker only has to hold a fraction, in particular approximately one kilogram, of the weight of the unit 26 and align it in the dishwasher 1. The unit 26 is located here, for example, in the area to the right of the front V of the dishwasher 1 and extends from the front V almost to the back of the dishwasher 1. The installation position is, however, variable depending on the spatial conditions.

[0087] In the installed position, only the supply line 22 and the discharge line 23 for washing liquid and an electrical line EL to the electrical connection 25 of the heat pump 14 and, if necessary, a communication line to the communication interface connection, in particular the data bus connection, have to be installed in the dishwasher 1, so that the time and effort required for this are extremely low.

[0088] The electrical connection 25 is part of the electrical module 37, which may also include sensors and the communication interface connection, in particular the data bus connection, and can preferably be formed via a snap-in connector, such as a so-called snap-in connector or snap-in 2.5 connector. The electrical module 37 is provided here in Figure 3 as a whole with a splash guard cover. According to Figure 3, the supply and discharge lines 22, 23 for rinsing liquid 24 are preferably connected to the inlet connection S22 and the outlet connection S23 of the heat transfer line section or pipe section 28, which is in thermally conductive contact with the tube of the condenser 18 and through which rinsing liquid can flow or flows. For this purpose, the supply line 22 and the discharge line 23 can expediently be designed as hose lines that can be plugged onto the connections S22, S23.In Figure 3, the flushing fluid 24 conveyed through the heat transfer line section 28 and its flow direction are symbolized by a separate arrow. The working fluid 17 flowing through the condenser 18 in the opposite direction to the flow direction of the flushing fluid 24 (countercurrent principle) is represented by a separate arrow in Figure 3.

[0089] Before inserting the heat pump 14 into the dishwasher, at least the essential components of the heat pump 14, in particular its compressor 16, its condenser 18, its expansion element 19 and its evaporator 20, as well as, if applicable, the air conveying unit 39 assigned to the evaporator 20, are expediently arranged on the support unit 15 holding them. This allows the support unit 15 to form a coherent, portable unit 26 with the components of the heat pump 14 during the assembly process, i.e. during the manufacture of the respective dishwasher, and to be installed as such in the respective dishwasher to be manufactured. In particular, the heat pump 14 can be assembled before being installed in the dishwasher 1, filled with working medium 17 through the filling connection 31, and tested for functionality. In particular, it can also be tested for leaks in its working medium circuit before being installed.

[0090] This module unit 26 can be used with the mechanically fixed components of the heat pump 14 together with the support unit 15 holding them as a modular unit in a permanent installation position or end position in the dishwasher 1.

[0091] The carrier unit 15 can be delivered filled with the mounted components of the heat pump 14 and the working medium 17 of the heat pump 14 for assembly of the dishwasher 1, either from the manufacturer's own factory or from a supplier. For this purpose, the carrier unit 15 with the mounted heat pump 14 forms a mechanically stable unit 26 that can be installed as a whole in the dishwasher 1. This unit is supported and held together by the carrier unit 15, which in this exemplary embodiment is preferably positioned horizontally in the installed position. This creates a highly integrated unit. Overall, the modular unit 26 achieves a compact design, platform compatibility, space savings, and minimal impact on the production line.

[0092] Because the heat pump assembly is preferably filled with its working medium in advance, no explosion protection is necessary in the actual dishwasher assembly line, which represents a considerable simplification and an increase in safety.

[0093] The pre-testable module unit 26 also results in quality advantages, the process steps in pre-assembly can be automated, and the entire unit 26 can be obtained from a system supplier.

[0094] Figures 4 to 8 show the structural unit of the heat exchanger WT formed between the condenser 18 and the line section 28 through which the rinsing liquid 24 can flow or through, in various views, each in an individual part representation. Figure 4 illustrates the heat exchanger or heat transfer device WT from Figure 3 as a detail in a perspective view. Figure 5 shows the heat transfer device WT from Figure 4 in an end view, and Figure 6 in a side view. Figure 7 shows the heat transfer device WT in longitudinal section along the vertical line VI-VI in Figure 5, which runs along its axial length, and Figure 8 shows it in longitudinal section along the horizontal section line VII-VII in Figure 6, which runs along its axial length.

[0095] According to the exemplary embodiment of Figures 3-8, the heat transfer line section or heat exchanger WT has an at least approximately circular-cylindrical pipe section 28 on the inside, through which the flushing liquid can be conveyed, in particular pumped, for heating. In this exemplary embodiment, the inlet-side end face and the outlet-side end face of the pipe section 28 through which flushing liquid can flow or through which it flows are each expediently sealed in a liquid-tight manner with an end cap 34 or other end closure. The inlet-side end cap 34 has the inlet connection S22 for connecting the supply line 22, and the outlet-side end cap 34 has the outlet connection S23 for connecting the discharge line 23.Of course, it is also possible to connect the supply line 22 to the inlet-side end section of the pipe section 28 and the outlet line 23 to the opposite, outlet-side end section of the pipe section in another fluid-tight manner.

[0096] The heat-emitting line section 33, in particular the tube line, of the condenser 18 is wound helically or spirally on the outside of the at least approximately circular-cylindrical casing of the pipe section 28, which here preferably runs at least approximately straight in the axial direction. The condenser line section 33, in particular the condenser tube, is therefore wound helically or spirally on the outside of the axially extending circular-cylindrical casing of the pipe section 28. As a result, the condenser line section 33, in particular the condenser tube, is in thermal contact or in heat-conducting contact with the material orMaterial of the cylinder jacket of the pipe section 28, so that heat can be transferred from the working medium 17 flowing through the condenser line section 33, in particular through the condenser tube, through the contacting wall areas of the pipe section and the condenser line section 33, in particular the condenser tube, wound around it, to the rinsing liquid flowing through the interior of the pipe section 28, with high heat transfer, ie with as little loss as possible.

[0097] The pipe section 28 through which the rinsing liquid to be heated flows or through which it flows is thus preferably arranged within the winding structure of the heat-dissipating line section 33, in particular the tube, of the condenser 18. It may be particularly advantageous if two adjacent turns of the line section 33 of the condenser 18, in particular the condenser tube, along the axial longitudinal extent of the pipe section 28 are located close to one another, in particular in contact with one another.Due to the high winding density of the condenser line section, in particular the condenser tube, which is ensured in this way, this, in particular this, provides a sufficiently high thermal output density on the outer jacket of the pipe section 28 with respect to its predetermined axial length, which is limited in particular by the limited space in the base area 12 of the dishwasher 1, which is necessary for heating the washing liquid 24 to a desired target temperature within a predetermined period of time.

[0098] It can be particularly advantageous if the condenser tube 33 is wound spirally onto the pipe section 28 with a radially inwardly directed mechanical holding force. It can be particularly advantageous if the condenser tube is in the form of a prefabricated helical spring, the inner diameter of which is selected to be smaller than the outer diameter of the pipe section, and is applied, in particular pushed, onto the pipe section 28 with a radial contact force while radially expanding its inner passage. It can also be particularly advantageous if the condenser tube 33 is held externally on the pipe section 28 by means of thermally conductive solder paste, thermally conductive brazing solder, or thermally conductive adhesive. Generally speaking, it can be particularly expedient if the condenser tube 33 and the pipe section 28 are cast, overmolded, or soldered together using a thermally conductive material.In particular, the heat-conducting material surrounds the condenser tube, viewed in cross-section, on a partial circumference or the entire circumference of its cylinder jacket and thus increases its heat transfer surface to the tube section 28. This improves the heat transfer from the working medium 17 through the wall of the condenser tube 18 and the wall of the tube section 28 to the flushing liquid 24.

[0099] In order to ensure efficient heat transfer from the inner wall of the circular cylinder shell of the pipe section 28 to the flushing liquid 24, a guide aid 29 is introduced into the circular cylinder shell of the pipe section 28, by means of which guide aid the flushing liquid 24 to be heated is guided or forced outwards to the inner wall 28a of the circular cylinder shell of the pipe section 28, which is in heat exchange contact with the condenser 18, in which the working medium 17 flows spirally around the outside of the pipe section 28 along its longitudinal extent as an external medium. In this exemplary embodiment, the guide aid 29 is preferably designed as an at least approximately circular-cylindrical displacement body 30. It is arranged centrally in the circular-cylindrical pipe section 28.Its outer diameter is so much smaller than the inner diameter of the pipe section 28 that an at least approximately circular-cylindrical edge gap or flow channel 35 is formed between the displacement body 30 and the pipe section 28. The at least almost circular-cylindrical displacement body 30 is thus surrounded radially on the outside by the at least almost circular-cylindrical pipe section 28, at least almost concentrically, with a defined radial gap spacing, so that an at least approximately circular-cylindrical edge gap 35 is formed between them.The flushing fluid 24 to be heated forces its way through the at least nearly circular-cylindrical gap 35 provided between the at least nearly circular-cylindrical outer wall of this displacement body 30 and the at least nearly circular-cylindrical inner wall of this pipe section 28 at a higher speed than if it were passing through an identical pipe section without a displacement body (at the same volume flow rate). This promotes heat transfer from the inner wall 28a of the pipe section 28, whose circular-cylindrical shell is in heat-exchange contact with the heat-dissipating line section of the condenser 18, to the flushing fluid flowing through the at least nearly circular-cylindrical gap.

[0100] A further improved heat transfer from the working medium 17 flowing through the condenser 18 to the flushing liquid 24, which flows through the edge gap 35 between the displacement body 30 and the pipe section 28 surrounding it on the outside with a radial gap, can be achieved in particular by the guide aid 29 being designed in such a way that it forces the flushing liquid to be heated into a spiral path or helical line 32, which moves along the radially outer edge of the flow channel 35 provided in the pipe section 28 and thus along the inner wall 28a of the pipe section 28 along its axial longitudinal extent. This spiral path or helical line 32 increases the path that the flushing liquid 24 has to take through the pipe section 28, preferably by a multiple (compared to a merelyexclusively along the axial longitudinal extent of the pipe section 28, in particular a straight flow path which is present between the preferably circular-cylindrical outer wall of the guide aid 29 and the preferably circular-cylindrical inner wall 28a of the pipe section 28. Here, in the exemplary embodiment of Figures 3-8, the rinsing liquid 24 particularly advantageously circulates several times in the circumferential direction around the inner wall or inner shell 28a of the circular-cylindrical pipe section 28 during its helical or spiral or helical forward movement along the spiral path 32.

[0101] To create such a spiral flow of the rinsing fluid 25 through the edge gap space 35, in the exemplary embodiment according to Figures 3-8, a web element 31 is fixedly arranged on the outside of the circular cylinder jacket of the displacement body 30, projecting at least almost radially outwards. When viewed spatially, this web element runs continuously in a helical or spiral shape around the outside of the circular cylinder jacket of the displacement body 30 over its axial longitudinal extent. The web element 31 projects from the at least approximately circular-cylindrical outer jacket of the displacement body 30 to the at least approximately circular-cylindrical inner wall 28a of the pipe section 28, i.e., it extends to the inner wall of the pipe section and thus bridges the radial width of the edge gap.The web element 31 divides the at least approximately circular-cylindrical edge gap 35 present between the displacement body 30 and the pipe section 28 such that a helical or spiral flow channel 32 for flushing fluid is formed. In this exemplary embodiment, it winds around the at least approximately circular-cylindrical outer shell of the displacement body 30 along its axial longitudinal extent with several consecutive turns in the axial longitudinal direction.Between the successive turns of the helical web element 31 in the axial longitudinal direction, a spiral flow channel (as a guide path) 32 is created for the flushing liquid 24 on its axial path through the at least approximately circular-cylindrical flow channel 35 formed between the displacement body 30 and the pipe section 28, so that the flushing liquid is forced to circulate around the (inner) circumference of the pipe section 28 on its inner wall surface 28a several times during its axial movement, i.e., with a multitude of circuits or 360° revolutions. This improves the heat transfer from the inner shell or from the inner wall 28a of the pipe section 28, whose outer shell is in heat exchange contact with the condenser 18 arranged around it on the outside, to the flushing liquid 24 flowing through the spiral flow channel 32.

[0102] If necessary, it may be sufficient to generate a spiral flow of the rinsing liquid if the web element 31 extends in a spiral or helical manner only on an axial section of the circular-cylindrical outer shell of the displacement body 30.

[0103] To generate a spiral flow of the rinsing liquid 24, under certain circumstances even a single turn of the web element 31 may be sufficient, which divides the preferably at least approximately circular edge gap 35 between the displacement body 30 and the pipe section 28 into a spiral guide path 32 for the rinsing liquid.

[0104] If necessary, a plurality of web elements can also be wound in a corresponding manner, each in a spiral shape, around the at least approximately circular-cylindrical outer casing of the displacement body 30 along its axial longitudinal extent, at least in sections, i.e. partially or, particularly advantageously, continuously. Between the successive windings in the axial longitudinal direction between two helical web elements arranged offset from one another in the longitudinal direction at an axial distance, a spiral-shaped flow channel 32 (as a guide path) is formed, so that the rinsing liquid 24, on its axial path of movement through the circular-cylindrical through-channel 35 formed between the displacement body 30 and the pipe section 28, is forced to run around the circumference of the pipe section 28 on its inner wall surface 28a during its axial movement - preferably several times, i.e. with a large number of revolutions or 360° rotations.

[0105] Additionally or independently of this, one or more such helical web elements 31 can be provided, in particular attached, on the inner wall 28a of the heat exchanger tube section 28, projecting inwards towards the outer wall of the displacement body 30, in particular projecting radially inwards, and preferably extending to the outer jacket of the displacement body 30. If necessary, it is also possible for the tube section 28, viewed in cross-section, to have a round symmetry shape that deviates from its advantageous circular shape shown in the exemplary embodiment of Figures 3 - 8, such as an oval geometric shape. Non-round cross-sectional geometric shapes, such as a flat rectangular cross-sectional geometric shape, are also possible for the tube section through which the rinsing liquid to be heated flows.In these modifications, the displacement body can also be expediently arranged within the pipe section and configured with a cross-sectional geometry corresponding to or matching the cross-sectional geometry of the pipe section, but reduced in size compared to the cross-sectional geometry, such that an edge gap or flow channel with a corresponding cross-sectional geometry is created between the displacement body and the pipe section. Viewed from the inside outward, the displacement body, the edge gap, the pipe section, and the line section, in particular the tube, of the condenser are thus arranged at least almost concentrically to one another.

[0106] If the spiral path has a radial extension of 2 to 10 mm (millimeters), in particular of 2.5 mm to 8 mm, preferably of 1.5 to 4 mm (millimeters), inwards from the inner wall 28a of the pipe section 28, on the one hand, a close proximity to the externally running working medium of the heat pump, such as 14, is achieved for the entire flushing fluid running in this spiral path - with the corresponding improvement in the heat transfer to the flushing fluid. On the other hand, a sufficient radial height of the spiral path still remains in order to advantageously avoid turbulence and to ensure laminar flow with a high volume flow, particularly in a boundary layer to the inner casing of the pipe section.

[0107] In particular, the spiral path 32, which defines the flow path for the flushing liquid through the pipe section 28, viewed across its axial length, has a total length of at least three times the axial length LR of the pipe section 28, in order to ensure a large flow path for the flushing liquid with the associated high velocity of the flushing liquid, despite the short axial length LR of the pipe section 28 and the condenser line section spiraling or winding around it on the outside. Preferably, the spiral path 32, which defines the flow path for the flushing liquid through the pipe section 28, viewed across its axial length, has a total length of at least five times the axial length LR of the pipe section, in order to achieve a particularly large increase in the flow velocity of the flushing liquid.

[0108] If there are no more than six to eight turns of the spiral path of the rinsing liquid, an associated flow resistance which counteracts the forward movement of the rinsing liquid can nevertheless remain sufficiently low in order not to overload a pump which conveys the rinsing liquid through the pipe section of the heat transfer device, which pump can be formed in particular by the circulation pump of the hydraulic or circulation circuit of the dishwasher or by a specially provided feed pump, and in order to prevent a drop in the volume flow of the rinsing liquid when flowing through the pipe section of the heat transfer device.

[0109] In this exemplary embodiment, the axial length LR of the heat exchanger pipe section 28 is advantageously between 10 and 30 cm (centimeters), in particular between 13 and 18 cm (centimeters). This short length of the pipe section 28 is helpful for enabling an overall compact design of the heat pump 14 and for keeping the proportion of washing liquid flowing through the pipe section 28 small. This makes the heat transfer from the working medium 17 to the washing liquid more efficient. Furthermore, the installation space required for the heat transfer device WT, particularly in the base or base support of the dishwasher below its washing container, is small.

[0110] If the pipe section 28 for the flushing liquid 24 is made, in particular, of stainless steel, high stability is achieved, along with easy machining and good corrosion resistance to the flushing liquid flowing through it. Such a stainless steel pipe section can have an (outer) diameter of typically 25 - 80 mm, in particular 30 to 50 mm (millimeters). (With a negligible wall thickness, such as approximately 0.8 mm for the pipe section, its inner diameter is only slightly smaller than its outer diameter.) The spiral line 33 for the working medium 17 or the tube 33 of the condenser 18, in the exemplary embodiment, preferably has a total winding length of 2 m (meters) to 5 m and an (inner) diameter of 3 mm to 8 mm. (With a negligible wall thickness, such as approximately 0.7 mm for the condenser tube, its outer diameter is only slightly larger than its inner diameter.)

[0111] In this embodiment, when the heat pump arrangement is switched on, the working medium flows through the line spirally arranged on the outside of the pipe section with a mass flow of between 2 kg / h (kilograms per hour) and 10 kg / h.

[0112] In particular, in this embodiment, it may be expedient for a perfect heat transfer from the inner wall 28a of the pipe section 28 to the flushing liquid 24 if the volume flow of the flushing liquid through the, in particular spiral-shaped, passage gap 32 formed between the inner wall 28a of the pipe section 28 and the outer wall of the displacement body 30 is selected between 2 l / min and 15 l / min.

[0113] Since the rinsing liquid 24 flows as the internal medium in the pipe section or pipe section 28 and the working medium 17 of the heat pump 14 flows as the external medium through the heat transfer line section 33 of the condenser 18, which is only in heat exchange contact or heat conduction with the pipe section 28 from the outside, there is no penetration or crossing of the flow channel 35 of the pipe section 28 through which the rinsing liquid 24 flows by the line section 33 of the condenser 18. The flow channel 35 of the pipe section 28 through which the rinsing liquid 24 flows is therefore kept free from the line section 33 of the condenser 18, so that no special requirements are placed on it with regard to corrosion protection, resistance to rinsing solutions, and / or food safety.If the line section 33 through which the working medium flows, in particular the tube, of the condenser 18 does not run at any point in the flow channel 35 of the pipe section 28 through which the flushing liquid 24 flows, this is particularly advantageous from a structural and thermodynamic perspective. In particular, there is no increase in the flow resistance for the flushing liquid 24, which would be the case if the line section 33 of the condenser 18 were partially or entirely accommodated within the flow channel 35 of the pipe section 28 for flushing liquid 24. In this case, in particular the inlet-side connection and the outlet-side connection of the line section 33 of the condenser 18 would penetrate the casing or the inlet-side end closure 34 and the outlet-side end closure 34 of the pipe section 28 for flushing liquid, which would disadvantageously result, for example, in additional sealing points.

[0114] If the line 33 of the condenser 18, which is preferably wound in a spiral shape around the pipe section 28 through which the rinsing liquid 24 to be heated flows or can flow, is formed or manufactured from copper, this is particularly advantageous. The entire working medium 17 of the heat pump arrangement 14 can then be conducted continuously through copper lines 21 to and from the compressor 16. This facilitates the production of the heat pump circuit 14. In addition, the heat pump circuit 14 can have at least almost uniform thermal conductivity over the entire course of its lines 21, which facilitates its energy-efficient design and configuration. In particular, a transition to other materials such as stainless steel for the heat transfer line section 33 of the condenser 18 is avoidable, i.e. not necessary. This is because the line section 33 of the condenser 18 does not come into contact with the rinsing liquid 24 to be heated.Quite differently, however, a change from a copper line, preferably to a stainless steel line, would be necessary for the condenser 18 if the latter were arranged in the flow channel 35 of the pipe section 28 carrying the rinsing liquid 24 in order to avoid undesired or inadmissible introduction of copper ions into the rinsing liquid and / or corrosion of the line section 33 of the condenser 18.

[0115] As an alternative to copper, the lines for the working medium of the heat pump arrangement (and thus in particular the condenser line) can, if necessary, be made entirely of aluminum. Plastic lines, for example with a metal coating on the inside, are also possible as line sections. The radial center region of the pipe section 28 advantageously remains free of rinsing liquid 24 due to the displacement body 30 accommodated there. In the longitudinal sections of the heat transfer device 14 in Figures 7 and 8, the interior of the displacement body 30 is shown as empty for the sake of simplicity of the drawing. However, one or more functional units of the dishwasher can also be accommodated inside the displacement body 30, in particular in a liquid-tight manner.For example, the interior of the displacement body 30 can accommodate the condensate pump KP (see Figure 2), by means of which condensate can be pumped from the collecting tray AW, which is arranged below the evaporator 20 of the heat pump 14, e.g., into the rinsing tank 5. In particular, one or more sensors, such as temperature sensors, can also be arranged inside the displacement body 30. If the displacement body 30 is made of a UV-transparent material, in particular plastic, a UV light source, such as a UV light tube or a circuit board equipped with one or more UV LEDs, in particular UV-C LEDs, can advantageously be accommodated inside this displacement body 30.In this way, the rinsing liquid 24 flowing through the pipe section 28 of the heat transfer device 14 can be disinfected as needed, thus enabling a hygienic operation of the dishwasher 1 to be implemented in a simple manner.

[0116] For ease of manufacture, the displacement body 30 can be made of plastic, for example, as an injection-molded plastic part. The displacement body 30 itself does not need to meet any thermal conduction requirements, so no metallic material is required.

[0117] The displacement body 30 can preferably be pressed into the pipe section 28 to achieve a high degree of tightness. Other mounting arrangements are also possible. In this case, absolute tightness of the outwardly, in particular radially outwardly facing web element 31 of the displacement body 30, provided according to an advantageous variant, or of the outwardly, in particular radially outwardly facing webs 31, provided according to an advantageous variant, relative to the inner wall 28a of the heat exchanger pipe section 28 is not absolutely necessary. Regarding the embodiment of Figures 3-8, the following points can be summarized as advantageous:

[0118] At least the supply line 22 and the discharge line 23 for the flow of the flushing liquid 24 to be heated are assigned to the pipe section 28 of the heat exchanger WT. Since the pipe section 28 is externally wrapped with the heat-dissipating line section 33 of the condenser 18, through which the working medium 17 of the heat pump circuit 14 flows, this ensures that heat transfer from the working medium to the flushing liquid takes place with a high heat transfer rate through the contacting walls of the pipe section 28 and the line section 33 of the condenser 18.

[0119] This pipe section 28 has a round cross-section, which is not mandatory. It is also not mandatory for the pipe section 28 to be made of stainless steel. The inner diameter of the pipe section 28 can typically be approximately 25 to 80 mm (millimeters), in particular between 30 and 50 mm.

[0120] In any case, in the pipe section 28, the flushing liquid 24 flowing through it can be guided by a guide aid 29 to a radially outer edge zone near the inner wall 28a of the pipe section 28 in order to be as close as possible to the outer medium (working medium 17) that flows in the line section 33 of the condenser 18 wound around the pipe section 28, and thus to improve the effectiveness or efficiency of the heat transfer from the working medium 17 to the flushing liquid 24. The flushing liquid 24 (i.e. the inner medium) is thus guided by the guide aid 29 into intimate heat exchange contact with the working medium 17 (outer medium) flowing spirally around the outside of the pipe section 28.

[0121] In the exemplary embodiment shown here, the axial length LR of the pipe section 28 is expediently between 10 and 30 cm (centimeters), in particular between 13 and 18 cm. This is helpful for enabling an overall compact design of the heat pump 14 and for keeping the proportion of liquid flowing through the condenser 18 small, which improves the energy efficiency of heat transfer from the working medium to the flushing liquid. The volume flow for the flushing liquid 24 is preferably between 2 l / min and 15 l / min (liters / minute), so that the heat exchanger WT can be kept very compact.Due to the geometry formed with the guide aid 29 in the pipe section 28 in the form of an edge gap, the heat exchanger WT can preferably only provide a flow volume of approximately 20 to 150 milliliters for the rinsing liquid to be heated (if the rinsing liquid 24 is conveyed through the pipe section 28 of the heat exchanger WT for its heating).

[0122] The guide aid 29 is constructed in such a way that the flushing liquid 24 is not only forced into the annular gap 35 on the inner wall 28a of the pipe section 28 but also into a spiral path 32 in a radially outer edge zone on the inner wall 28a of the pipe section 28.

[0123] This spiral path 32 is formed here such that the guide aid 29 forms a displacement body for the rinsing liquid 24, which is introduced into the pipe section 28 and thus forces the rinsing liquid 24 into a radially outer region. The main body of the displacement body 30, which is round-cylindrical in this case, maintains a radial distance of preferably approximately 1.5 to 4 millimeters from the inner wall 28a of the pipe section 28. From this cylindrical body of the displacement body 30, web sections or winding sections of the web element 31 then extend around the cylinder body in a helical manner, i.e. with a circumferential component and an axial component, and which ideally extend until they are in tight contact with the inner wall 28a of the pipe section 28.

[0124] The displacement body 30 thus blocks the inner clear width of the pipe section 28 for flushing fluid 24 except for an edge gap 35 provided with one or more guide paths 32 for a spiral flow, which imparts a movement component in the circumferential direction and a movement component in the axial direction to the flushing fluid 24. Due to the guide aid 29, the central line of the pipe section 28 with respect to the radial extent is therefore free of medium flow at all times. As a result, the space radially within the main or cylindrical body of the displacement body 30 can also be used for other components, for example, for a condensate pump that pumps condensate back into the flushing tank 2. The displacement body 30 can be made of plastic, for example, as an injection-molded part.

[0125] In order to achieve a high degree of tightness between the web sections of the web element 32 and the inner wall 28a, the displacement body 30 can be pressed into the pipe section 28. However, a certain leakage current between the radially outer ends of the web sections of the web element 32 and the inner wall 28a is harmless, so that pressing in is not absolutely necessary.

[0126] As can be seen in the longitudinal sectional views according to Figure 7 and Figure 8, the spiral path 32 has a total length of at least three times the axial length LR of the pipe section 28.

[0127] In particular, the spiral path 32 has a total length of at least five times the axial length LR of the pipe section 28. It encircles the circumference of the cylinder body of the displacement body 30 five times, for example, on a spiral path near the inner wall 28a of the pipe section 28.

[0128] If, as shown here, the flushing liquid 24 is the inner medium and the working medium 17 of the heat pump 14 circulates around the condenser 18 on the outside, the flow path of the working medium 17 does not have to cross the flow path of the flushing liquid 24 at any point.

[0129] The diameter of the pipe section 28 within the spiral path 32 is significantly larger for the inner medium (the flushing liquid 24) than the diameter of the spiral line 33 for the outer medium, i.e. the working medium 17.

[0130] The working medium 17, also called refrigerant, of the heat pump 14 is guided here in a spiral line 33 for the external medium. The spiral line 33 is wound around the relatively large diameter pipe section 28, resulting in a large condensation surface for the working medium 17 as the external medium. The diameter of the line 33 is very small compared to the diameter of the pipe section 28. This line 33 is made of copper or aluminum throughout the entire heat pump 14. Transitions made of foreign materials can therefore be avoided, which is very advantageous from a design perspective. In addition, pre-assembly of the line 33 is also possible before the heat pump 14 is installed in the dishwasher, so that it can also be filled with the working medium 17 in advance.

[0131] In particular, the spiral line 33 through which the working medium 17 flows is held to the pipe section 28 by heat-conducting solder paste, brazing solder, or adhesive. This creates a large and effective condensation surface for the working medium 17 on the condenser 18.

[0132] The pipe section 28 can be closed at its axial ends by the extending end caps 34, in particular made of plastic, each of these end caps being provided with the extending connection 22, 23 for the rinsing fluid 24. The end caps 34 can guide the rinsing fluid 24 into the spiral path 32 at the radially outer edge of the guide aid 29 designed as a displacement body 30.

[0133] The heat pump 14 is assembled, filled with working fluid 17, and tested for functionality prior to installation in the dishwasher 1. Likewise, the heat pump 14 is advantageously tested for leaks in the areas carrying the working fluid prior to installation in the dishwasher 1. The essential components of the heat pump 14 are mechanically fixed to a supporting unit 15, for example, a board-like or frame-like unit.

[0134] Very advantageously (not shown here) the support unit 15 is pre-assembled with several mechanical attachment aids for attaching the components 16, 18, 19, 20, 21, and possibly 39 of the heat pump 14. Such attachment aids can have various mechanical designs and, for example, each comprise a screw thread or spring clip for firmly holding the aforementioned components.

[0135] Overall, the support unit 15 with the heat pump 14 mounted thereon forms the mechanically stable unit 26, which is portable as a whole for installation in the dishwasher 1. This unit can also be transported between different plants or factories or different production lines and can also be completely removed from its installation position in the dishwasher 1 for repair purposes.

[0136] In the installation position in the dishwasher 1, only a supply line and a drain line for washing liquid and an electrical connection to the heat pump 14 and, if necessary, a communication interface, in particular a data bus connection, have to be installed.

[0137] The connection of the supply and discharge lines 22, 23 for rinsing liquid to the pipe section 28 is formed here in the exemplary embodiment, for example, via two nozzles S22, S23 assigned to the pipe section 28 of the heat exchanger WT and via two hoses that can be plugged onto them.

[0138] During assembly, before inserting the heat pump 14 into the dishwasher, at least one compressor 16, one condenser 18, one expansion valve 19, and one evaporator 20 are fixedly mounted on a supporting unit 15. Thus, before installation in the dishwasher 1, the heat pump 14 can be mounted, filled with working fluid 17, and tested for functionality.

[0139] Additionally or alternatively, at least the essential components of the heat pump 14 can be mechanically fixed to a supporting support unit 15 prior to installation in the dishwasher. Thus, during the assembly process during installation in the dishwasher 1, the support unit 15 can form a coherent, portable unit 26 with the components of the heat pump 14, so that the heat pump 14 and the support unit 15 form a compact, modular, and individually transportable unit.

[0140] In this way, a heat pump can be integrated into a dishwasher, particularly a household dishwasher, which further significantly reduces its energy consumption. The heat pump can be designed to be cost-optimized, efficient, and compact. In particular, it is designed to require as few assembly steps as possible during the final dishwasher assembly. It can also be integrated into the respective dishwasher in such a way that only minor changes need to be made to the underlying appliance platform of the respective dishwasher. Furthermore, it is largely ensured that the normal operating conditions of a dishwasher with a heat pump do not deviate too much from a standard dishwasher without a heat pump. This applies particularly with regard to water consumption when running a dishwashing program using the heat pump.

[0141] The structure of the heat pump is expediently realized in such a way that the compressor, the condenser, the expansion element, in particular the expansion valve or capillary tube, and the evaporator including the refrigeration circuit piping (lines carrying the working fluid) are combined in a compact unit.

[0142] This unit is preferably held together by a mounting plate / support component, which can be a single or multi-part assembly. The heat pump unit is secured in the dishwasher via this support structure.

[0143] Thus, the refrigeration circuit or heat pump circuit can be advantageously closed at a pre-assembly location (preferably completely soldered or tightly pressed), filled with refrigerant (= working medium) and pre-tested.

[0144] This heat pump module is then conveniently delivered to the dishwasher production line pre-assembled, filled and pre-tested and only requires the power connection, possibly also the communication connection, in particular the data bus connection, the connection to the wash liquor circuit (water circuit) with inlet and outlet and, if necessary, a connection for the condensate discharge for the condensate accumulating on the evaporator.

[0145] Additionally, the control unit for the electrical components and sensors of the heat pump system can also be integrated into the heat pump module if necessary. The compressor motor, the fan assigned to the evaporator, the condensate pump, possibly also the water circuit valve (see VA in Figure 2), and sensors such as temperature sensors assigned to the evaporator can be conveniently connected to this control unit. Thus, only one electrical connection for the power and the data bus connection would be required.

[0146] The following functions are preferably integrated into the support component(s): • Condensate collection tray below the evaporator (optional)

[0147] • Mounting the condensate pump

[0148] • Fixing the compressor » Fixing the fan

[0149] • Air flow, at least partial areas of the air flow from the technical area, in particular the base support, of the dishwasher or the dishwasher beyond the evaporator out of the device

[0150] • Fixing the evaporator » Fixing the heat pump piping and cabling (especially for electrical power supply and communication)

[0151] • Possible fixing of the control module for the heat pump unit

[0152] • Fastening and supporting the heat pump unit in the base support of the dishwasher

[0153] In order to be able to realize this compact unit, the heat pump arrangement can in particular have the following advantageous heat transfer device between its condenser and a pipe section to be supplied with rinsing liquid to be heated:

[0154] The relatively thin refrigerant pipe or condenser tube is wrapped around a significantly larger pipe section, particularly a significantly larger stainless steel pipe, through which the flushing fluid to be heated flows, in order to generate as much condensate surface area as possible for the refrigerant or working fluid. The refrigerant pipe can thus advantageously continue to be manufactured from copper, as is usual with heat pumps, eliminating problematic pipe connections made of different materials within the heat pump circuit that require soldering or pressing.

[0155] This copper pipe of the condenser is then preferably soldered onto the stainless steel pipe to ensure the best possible heat transfer.

[0156] A displacement component is pressed or mounted inside the stainless steel pipe to direct the flow. This component features a spiral rib on the outside, thus directing the flow of the rinsing solution or rinsing liquid and ensuring heat dissipation on the inner wall of the stainless steel pipe. The stainless steel pipe is sealed at the ends with end caps, each of which incorporates a connection for the water / rinsing solution circuit.

[0157] The displacer component and the end caps can preferably be made of plastic, since there are no requirements regarding their thermal conduction.

[0158] Due to this advantageous design of the heat transfer device, it is possible for only a portion of the total wash liquor volume (bypass flow parallel to the wash circuit or recirculation circuit) to flow through the heat transfer device's pipe section, while the water volume in the pipe section is also relatively small (preferably less than or equal to 150 ml). This ensures that water consumption is only slightly higher than with a conventional dishwasher (without a heat pump).

[0159] In addition, the bypass circuit BK, in which the pipe section of the heat transfer device is inserted, can be switched on or off using the rinsing liquid valve (see VA in Figure 2), which makes it possible to minimize the circulation (required water quantity) for the circulation pump circuit or circulation circuit in unheated rinsing liquid baths, especially water baths.

[0160] With this solution, the refrigeration circuit or heat pump circuit can be constructed entirely with copper pipes for the working fluid, which is advantageous in terms of connections / soldering. The refrigeration circuit can be conveniently closed, filled, and tested during the pre-assembly of the heat pump unit.

[0161] The connections of the cooling circuit advantageously do not cross the rinsing water circuit or circulation pump circuit at any point and do not come into contact with the rinsing water.

[0162] As an alternative to copper, the lines for the working fluid of the heat pump assembly (and thus, in particular, the condenser lines) can be made entirely of aluminum. Plastic lines, for example, with a metal coating on the inside, are also possible.

[0163] Optionally, the displacer body could be made of a UV-transparent plastic, and a UV light tube or a circuit board equipped with several UV-C LEDs could be positioned in the center of the displacer body, which could serve as an additional feature for disinfection (hygienic function) of the wash liquor. Optionally, the space inside the displacer body could also be used to position an electrically operated condensate pump.

[0164] It might also be possible to design the condensate pump as a Venturi pump. This Venturi nozzle could also be integrated into one of the end caps. With such a solution, a small check valve should also be included to ensure that fluid from the rinse water circuit or circulation pump circuit can never flow back into the condensate pan.

[0165] The advantages of this heat pump arrangement are as follows:

[0166] • Compact design

[0167] • Platform compatibility

[0168] • Gain in installation space

[0169] • Low impact on production line

[0170] (especially when changing models within the production line)

[0171] • During dishwasher production itself, no coolant or

[0172] Working medium is filled into the heat pump circuit (explosion protection is not necessary in the final dishwasher assembly)

[0173] • Quality advantages through pre-testable heat pump unit

[0174] • Possibility of automating process steps in pre-assembly

[0175] • Possibility of purchasing the heat pump unit from a system supplier

[0176] • Modular replacement of the heat pump is also possible at customer service

[0177] Special advantages of this design of the heat transfer device or heat exchanger are in particular:

[0178] • Only a small amount of water or flushing liquid flows through the pipe section of the heat exchanger (less than 150ml), thus the water consumption is only marginally affected; the smaller the circulation volume of flushing liquid for the circulation pump can be, the lower the energy consumption for heating this circulation volume of flushing liquid

[0179] • Refrigerant connections are completely separated from the rinse water circuit connections and / or bypass circuit connections; this offers advantages in material selection (as explained in detail above)

[0180] • The rinsing liquor circuit is not disturbed by the pipe section of the heat transfer device, which leads to better efficiency in the flusher hydraulics

[0181] • The bypass circuit with the heat transfer device integrated into it is only connected to the circulation pump circuit in the heated rinsing baths (i.e. partial rinsing cycles with rinsing liquid to be heated), i.e. the bypass circuit and thus the pipe section of the heat transfer device is only supplied with rinsing liquid in the heated rinsing baths, otherwise not in the unheated partial rinsing baths; thus, no additional water consumption is required in the unheated baths

[0182] • Optional hygiene function

[0183] • Optional implementation of a Venturi pump, which saves costs

[0184] By means of the switched-on heat pump arrangement, the rinsing liquid which is used for a partial rinsing phase, such as the cleaning phase and / or the final rinsing phase of a dishwashing program to be carried out, and for which heating to a specific target final temperature is required during this partial rinsing phase, can be heated at least partially, i.e. partially or completely, to the respective desired target final temperature. The heat pump operation then ensures electrical energy savings compared to a conventional dishwashing program of a dishwasher (without heat pump or without heat pump operation), which only, i.e. exclusively, uses a conventional electrical water heater in the circulation circuit or circulation pump circuit to heat the rinsing liquid which is required for the respective partial rinsing phase, such asthe cleaning phase and / or final rinse phase of a dishwashing program to be carried out and for which heating to a specific target final temperature is required during this partial rinse phase.

[0185] In particular, it can be advantageous for carrying out a variety of dishwashing programs if the dishwasher, in particular a household dishwasher, equipped with the heat pump arrangement according to the invention still has an electric liquid or water heater in its circulation circuit. For example, the circulation pump (such as UP in Figure 2) can comprise an electric water heater, i.e. an electric water heater can be integrated into the housing of the circulation pump in order to be able to heat the dishwashing liquid pumped by it, if necessary, additionally or independently of the heat pump. Alternatively, a water heater can be provided outside the circulation pump as a separate component of the circulation circuit. In particular, it can be fluidically arranged downstream of the circulation pump in its conveying direction, for example by being inserted into the connecting line between the circulation pump and the water switch.

[0186] During an energy-saving program, i.e. a so-called eco-dishwashing program, it is particularly advantageous if the water heating remains switched off throughout and in all partial wash phases (e.g. in the cleaning phase and in the final rinse phase) of the eco-dishwashing program, in which a certain, partial wash phase-specific amount of rinsing liquid is to be heated to a desired target final temperature, this partial wash phase-specific amount of rinsing liquid is heated exclusively by means of the heat pump.

[0187] In order to be able to carry out a dishwashing program that is different from the Eco dishwashing program, such as an intensive cleaning program that requires a higher target final temperature than the Eco dishwashing program in the respective partial washing phase, such as the cleaning phase and / or the final rinse phase, or a quick cleaning program that specifies shorter durations for the respective partial washing phase, such as the cleaning phase and / or the final rinse phase, as energy-efficiently as possible, the respective partial washing phase-specific, ieThe amount of rinsing liquid individually assigned to the respective partial rinsing phase is first heated to a first heating temperature (greater than its inlet temperature when entering the rinsing tank) during a first heating phase exclusively by means of the switched-on heat pump, then the heat pump is switched off, and subsequently the rinsing liquid partially heated by the heat pump is further heated to the respectively desired, higher target final temperature by means of the only then switched-on electric water heater of the circulation circuit. In summary and / or general terms, a dishwasher, in particular a household dishwasher, is provided into which a heat pump can be integrated in an improved manner, with the aid of which the electrical energy consumption of the dishwasher can be significantly reduced compared to conventional dishwashers.

Claims

Patent claims 1. Dishwasher (1), in particular a household dishwasher, with a heat pump arrangement (14) comprising at least one compressor (16), a condenser (18), an expansion element (19) and an evaporator (20), which are connected to one another via line sections (21) for conveying a working medium (17) that changes its state of aggregation during operation of the heat pump arrangement (14), wherein the heat pump arrangement (14) is assigned a heat transfer device (WT) by means of which, during operation of the heat pump arrangement (14), heat can be transferred from the working medium (17) flowing through the condenser (18) to the washing liquid (24), which can be circulated or is circulating in particular in the dishwasher (1), in order to heat the latter, characterized in that the heat transfer device (WT) is designed in such a way thatthat the rinsing liquid (24) to be heated flows through at least one pipe section (28) and is guided as an inner medium flowing through it by means of a guide aid (29) outwards to the inner wall (28a) of the pipe section (28), which is in heat exchange contact with the condenser (18), in which the working medium (17) flows around the pipe section (28) on the outside along its longitudinal extent in a spiral manner as an outer medium.

2. Dishwasher (1) according to claim 1, characterized in that the guide aid (29) forces the inner medium outwards into a spiral path (32) along the inner wall (28a) of the pipe section (28).

3. Dishwasher (1) according to claim 2, characterized in that the spiral path (32) has a radial extension of 2 to 10 mm (millimeters), in particular of 1.5 to 4 mm (millimeters), inwards from the inner wall (28a) of the pipe section (28).

4. Dishwasher (1) according to one of claims 2 or 3, characterized in that the spiral path (32) has a total length of at least three times the axial length (LR) of the pipe section (28) for rinsing liquid (24).

5. Dishwasher (1) according to at least one of claims 2 to 4, characterized in that the spiral path (32) has a total length of at least five times the axial length (LR) of the pipe section (28) for rinsing liquid (28).

6. Dishwasher (1) according to at least one of claims 1 to 5, characterized in that the flow path of the working medium (17) does not penetrate the flow path of the rinsing liquid (24) at any point.

7. Dishwasher (1) according to at least one of claims 1 to 6, characterized in that for the external medium (17) a line (33) of the condenser (18) is applied spirally on the outside of the pipe section (28) through which washing liquid (24) can flow or through which it flows, in thermal contact with the latter, in particular is wound spirally on the pipe section (28) with a mechanical holding force, is pushed onto the pipe section (28) as a prefabricated helical spring with a radial contact force, and / or is held on the outside of the pipe section (28) by means of heat-conducting soldering paste, hard solder, or adhesive.

8. Dishwasher (1) according to claim 7, characterized in that the spiral-shaped line (33) for the external medium is made of copper or aluminum.

9. Dishwasher (1) according to one of claims 7 or 8, characterized in that that when the heat pump arrangement (14) is switched on, the working medium (17) is conveyed through the line (33) arranged spirally on the outside of the pipe section (28) with a mass flow of between 2 kg / h (kilograms per hour) and 10 kg / h 10. Dishwasher (1) according to at least one of claims 7 to 9, characterized in that the spiral line (33) for the external medium has a total winding length of 2 m (meters) to 5 m and a diameter of 3 mm to 8 mm.

11. Dishwasher (1) according to at least one of claims 1 to 10, characterized in that the pipe section (28) for the inner medium is made of stainless steel.

12. Dishwasher (1) according to at least one of claims 1 to 11, characterized in that the pipe section (28) for the inner medium has an axial length (LR) of 10 cm to 30 cm (centimeters), in particular of 13 cm to 18 cm (centimeters).

13. Dishwasher (1) according to at least one of claims 1 to 12, characterized in that the pipe section (28) for the inner medium is round-symmetrical in cross-section, in particular at least approximately circular-cylindrical when viewed in three dimensions.

14. Dishwasher (1) according to at least one of claims 1 to 13, characterized in that the diameter of the pipe section (28) for the inner medium is significantly larger, in particular between 5 and 25 times larger, than the diameter of the spiral line (33) of the condenser (18) for the outer medium.

15. Dishwasher (1) according to at least one of claims 1 to 14, characterized in that the guide aid (29) is formed by a displacement body for the inner medium, which is introduced into the pipe section (28), in particular at least approximately centrally, and in particular is at least approximately circular-cylindrical (when viewed spatially).

16. Dishwasher (1) according to claim 15, characterized in that between the pipe section (28) and the displacement body there is an at least almost circular-cylindrical edge gap (35) through which the washing liquid (24) to be heated can be conveyed.

17. Dishwasher (1) according to one of claims 15 or 16, characterized in that the displacement body blocks the inner clear width of the pipe section (28) except for an edge gap (35) which is provided with one or more guide paths (32) for a spiral flow of the inner medium.

18. Dishwasher (1) according to claim 17, characterized in that the displacement body has on its outer casing one or more spiral-shaped web elements or web sections (31) projecting outwards in the direction of the inner wall (28a) of the pipe section (28), in particular reaching as far as the inner wall (28a) of the pipe section (28).

19. Dishwasher (1) according to at least one of claims 15 to 18, characterized in that the displacement body is made of plastic.

20. Dishwasher (1) according to at least one of claims 15 to 19, characterized in that the displacement body is pressed into the pipe section (28).

21. Dishwasher (1) according to at least one of claims 15 to 20, characterized in that the volume flow of the washing liquid (24) to be heated through the, in particular spiral-shaped, passage gap (32) formed between the inner wall (28a) of the pipe section (28) and the outer wall of the displacement body (29) is selected between 2 l / min and 15 l / min.

22. Dishwasher (1) according to at least one of claims 1 to 21, characterized in that the pipe section (28) can be closed towards its axial ends by end caps (34) or other end terminations, in particular made of plastic, wherein each of these end caps or other end terminations is provided with a further connection (S22, S23) for the rinsing liquid (24).

23. Dishwasher (1) according to at least one of claims 1 to 22, characterized in that due to the guide aid (29) the central region of the pipe section (28) with respect to the radial extent is free of medium flow at all times.

24. Dishwasher (1) according to at least one of claims 1 to 23, characterized in that the heat pump arrangement (14) is assembled, filled with working medium (17) and can be or is tested for function before installation in the dishwasher (1).

25. Dishwasher according to at least one of claims 1 to 24, characterized in that the heat pump arrangement (14) is tested for leak tightness of its areas carrying the working medium (17) before installation in the dishwasher (1).

26. Dishwasher (1) according to at least one of claims 1 to 25, characterized in that that at least the essential components of the heat pump arrangement (14) are mechanically fixedly arranged on a carrier unit (15) holding them.

27. Dishwasher (1) according to claim 26, characterized in that the mechanically fixed components of the Heat pump arrangement (14) together with the support unit (15) holding it as a modular unit in a permanent installation position in the Dishwasher (1) can be used.

28. Heat transfer device (WT) for the heat pump arrangement (14) of a dishwasher (1), in particular a household dishwasher, for heating washing liquid (24), in particular according to at least one of the preceding claims, characterized in that the heat transfer device (WT) is designed such that the washing liquid (24) to be heated flows through at least one pipe section (28) and, as an inner medium flowing through it, is guided outwards by means of a guide aid (29) to the inner wall (28a) of the pipe section (28), which is in heat exchange contact with the condenser (18), in which the working medium (17) flows around the outside of the pipe section (28) along its longitudinal extent in a spiral manner as an outer medium.

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