Dishwasher comprising a heat pump

Abstract

The invention relates to a dishwasher (1) comprising at least one heat pump (14) which comprises, as functional units, at least one compressor (16), a condenser (18), an expansion element (19), and an evaporator (20) which are connected to one another via pipe sections (21) for forwarding a working medium (17) which changes state during operation. The dishwasher is designed in such a way that the functional unit of the evaporator (20) comprises a plurality of heat exchanger elements (26) which are arranged side by side, in particular upright, and between which air (28) can be passed in order to transfer heat to the working medium (17), wherein the distance (d1, d2) between adjacent heat exchanger elements (26) varies along the path of the air (28) through the evaporator (20).

Description

[0001] Dishwasher with a heat pump

[0002] The present invention relates to a dishwasher, in particular a household dishwasher, with at least one heat pump comprising at least one functional unit of an evaporator, according to the preamble of claim 1.

[0003] It is known to provide dishwashers, in particular household dishwashers, with heat pumps to optimise the energy efficiency of such machines, in order to at least support the heating of the rinsing water circulating in the dishwasher and / or the drying of air from the washing container or washing chamber air, or, if appropriately designed, to achieve this entirely via the heat pump.

[0004] Such a heat pump is typically an air-source heat pump, which, during at least one dishwashing program, extracts heat from the ambient air during at least one heating phase of the dishwashing liquid and transfers it to the liquid via its condenser. If the air-source heat pump is also used to dry the dishwashing air during the drying phase of the dishwashing program, the dishwashing air to be dehumidified is passed through the evaporator to cool it and condense out any moisture. In the so-called functional unit of the evaporator, which does not have to form a closed structural unit, heat is transferred from the air flowing through the evaporator structure at any given time—for example, air drawn in from the kitchen where the dishwasher is installed—to a working fluid of the heat pump.In order to achieve a high level of effectiveness in heat transfer from the air as it passes through the evaporator to the working medium (given the size of the evaporator's functional unit), the evaporator has the largest possible surface area with which the air conveyed through it, in particular ambient air, can come into thermal contact. Typically, these surfaces are formed at least partially by heat exchange elements that are thermally connected to the evaporator's conduit tubes, through which the heat pump's working medium flows, in particular meandering tubes. The heat exchange elements run at least approximately parallel to one another; any two adjacent heat exchange elements typically have at least approximately the same transverse spacing (across their entire longitudinal extent) from one another. The heat exchange elements are expediently each flat; in particular, they are formed by fins, preferably sheets.Between these evenly spaced heat exchange elements, there are thus air channels or air passages, each having the same cross-sectional width over its entire length. These air passages are crossed by one or more line sections of the preferably meandering evaporator pipe through which the heat pump's working medium flows. In particular, the one or more tubular line sections of the evaporator through which the working medium flows penetrate the heat exchange elements transversely, in particular orthogonally, to their longitudinal extent. The heat exchange elements are thus arranged transversely, in particular orthogonally, to the one or more tubular line sections of the evaporator through which the working medium flows, in particular at least approximately rectilinearly. This evaporator arrangement is also referred to as a tube-fin arrangement.If the evaporator is arranged in such a way that its one or more line sections through which the working medium flows, in particular at least approximately straight, are laid at least approximately horizontally, the heat exchange elements are upright, in particular vertically upright.

[0005] To meet the efficiency requirement, these finned heat exchange elements should be as completely closed as possible and positioned close together to provide the largest possible total contact surface for the air flowing through the evaporator. This ensures that as much heat energy as possible from the air flowing through the air passages between the evenly spaced heat exchange elements can be transferred into the heat pump's working fluid.

[0006] On the other hand, in this conventional tube-fin evaporator, whose equidistantly arranged, fin-shaped heat exchange elements each have the same transverse distance between them over their entire air passage length, the small transverse distance between any two adjacent heat exchange elements, which is desired for a high heat transfer to the air flowing through, is associated with the risk that the cross-sectional area of ​​the air duct or air passage between any two adjacent heat exchange elements that is freely passable for air will be increasingly reduced by dust, lint, fibers, hair and / or similar over the course of the operating life of the respective dishwasher, or that the air ducts between the heat exchange elements will even become completely blocked by dust, lint, fibers, hair and / or similar.This is a particular problem with dishwashers, particularly household dishwashers that are located on the floor, when the air passed through the evaporator is mostly sucked in from the lower area of ​​the dishwasher, particularly in the base below the wash tub, and therefore close to the floor. This is because the ambient air that is sucked in then carries an increased amount of dust, fluff, fibers, hair and other dirt. However, if such dirt continues to reduce the cross-sectional area of ​​the air passage or the width of the gaps between the heat exchange elements, the function of the heat pump is impaired. In particular, there is a risk of the air ducts or ducts becoming blocked or closed.Air passages between the heat exchange elements with condensate droplets separated from the air and then later, during continued operation of the heat pump, also with ice are particularly high. This applies in particular to the air inlet side, especially the front side of the evaporator, which is exposed to the incoming air flow (and to pollution as well as the highest humidity in the air). However, if the air passages between the heat exchange elements become closed or blocked by icing while the heat pump is in use, the entire evaporator, including the area of ​​the evaporator behind the icing, will be disabled. It is then necessary to wait until the air passages blocked with ice have thawed.

[0007] The invention is based on the problem of achieving an improvement in the evaporator of a heat pump for a dishwasher, in particular a household dishwasher.

[0008] The invention solves this problem by a dishwasher having the features of claim 1. With regard to advantageous embodiments and further developments of the invention, reference is made to the further claims 2 to 22. Due to the fact that in a dishwasher, in particular a household dishwasher, with at least one heat pump, the functional unit of the evaporator comprises several adjacent, in particular upright, heat exchange elements, between which air can be passed to release heat to the working medium, wherein the distance between adjacent heat exchange elements (in the transverse direction to the air flow direction) varies over the path of the air through the evaporator, on the one hand, the problem can be counteracted that the distance becomes too narrow and therefore becomes dirty and / or iced over too quickly. On the other hand, the distance between any two adjacent heat exchange elements does not have to be continuous (i.e.The air passage or air duct between these adjacent heat exchange elements must be particularly wide. Otherwise, this would significantly impair the effectiveness of heat transfer from the air to the working fluid.

[0009] In order to counteract the described problem of the contaminants contained in the air supplied to the evaporator, it is particularly advantageous for the distance between adjacent heat exchange elements (in the transverse direction to the air flow direction) to be greatest on an air inlet side, in particular the front, surface of the evaporator, which first comes into contact with the incoming air.

[0010] If the distance (of the air passage or air duct) between each two adjacent heat exchange elements is reduced as the air travels through the evaporator, the effectiveness of the heat transfer is optimized in the area downstream of the air inlet side, in particular the air outlet side, preferably the rear area of ​​the evaporator, since contaminants carried in the air supplied to the evaporator have already predominantly settled in the area of ​​the air inlet side, in particular the front area of ​​the evaporator, in particular on the inlet side front edges of the heat exchange elements.Also, at least part of the moisture contained in the air supplied to the evaporator has already been condensed out of it in the air inlet side, in particular the front area, of the evaporator, so that the air arrives drier in the area of ​​the evaporator downstream of the air inlet side, in particular the air outlet side, preferably the rear, and the risk of icing is significantly reduced there.

[0011] It can be particularly advantageous if, along the path of the air through the evaporator, a larger, in particular at least a factor of two, transverse distance is provided between each two adjacent heat exchange elements in an air inlet-side, in particular front, region of the evaporator than in a region of the evaporator downstream of the air inlet-side, in particular air outlet-side, preferably rear. In other words, the air passage or air duct provided between each two adjacent heat exchange elements preferably has a larger cross-sectional width along an air inlet-side, air-flow-through longitudinal section of its longitudinal extent than in a second, in particular outlet-side, preferably rear, longitudinal section of its longitudinal extent downstream of the air inlet-side, i.e., a second, in particular outlet-side, preferably rear, longitudinal section of its longitudinal extent.Such an advantageously designed evaporator meets the requirements for its robustness against soiling and thus its long-term functionality over the operating life of the dishwasher, in particular household dishwashers, while at the same time ensuring sufficiently high effectiveness of heat transfer from the air to the working medium.

[0012] Because the heat exchange elements, in particular fins, are spaced apart from one another on the supply air side or air inlet side of the evaporator by a greater distance (than in an area of ​​the evaporator downstream of the air inlet side in the air flow direction, in particular the air outlet side, preferably the rear area of ​​the evaporator, ie than on its exhaust air side or air outlet side), the risk of closing, ie closing off, the air passages between the heat exchange elements of the evaporator in the area of ​​its air inlet during the execution of a dishwashing program with heat pump operation is lower, ie mitigated.Since during the respective dishwashing program with heat pump operation the air has its highest moisture content on the supply air side of the evaporator as it flows through the evaporator and thus at the inlet of the evaporator and becomes increasingly drier as it passes through the evaporator due to cooling and condensation of moisture, condensate and / or ice initially and increasingly forms in the inlet area of ​​the evaporator, in particular at its inlet where the air flows, and builds up there primarily on the inlet-side end faces where the air flows, as well as on the surfaces of neighboring heat exchange elements that are opposite one another in a transverse direction to the direction of air flow through the evaporator, in particular those that face one another. Contamination such asDust, lint, threads, hair and / or other contaminants are drawn in during a heat pump dishwashing program by the ambient air drawn in by the air conveying device, onto the air inlet of the evaporator and / or into the evaporator via the inlet side. Due to the now wider air passages between the heat exchange elements on the supply air side, accumulations, in particular adhesions, of condensate, ice and / or dirt in the area of ​​the heat exchange elements on the air inlet side do not lead as quickly to the clogging of the air cross-section of the respective air duct or air passage located between two transversely adjacent heat exchange elements, since its width orWidth is greater than the sum of the transverse dimensions of the possible accumulations of condensate, ice and / or dirt on two heat exchange elements located opposite each other in a transverse direction to the air flow direction during the execution of a dishwashing program with heat pump operation. In addition, there is the possibility that when the evaporator ices up, the contaminants carried in the air from its air inlet area, such as dust, lint, threads, hair, etc. ... are already bound to and / or in the ice and / or condensate in the area of ​​the evaporator's air inlet and are carried less or not further into the subsequent, in particular outlet-side, preferably rear, area of ​​the evaporator by the air flowing through it. In particular, when the condensate drips off and / or when the ice defrosts after the heat pump is switched off, the contaminants adhering to it and / or bound in it, such asDust, fluff, threads, hair, etc. ... are detached from the heat exchange elements and fall down with it. The evaporator can therefore be easily cleaned of contaminants such as dust, fluff, threads, hair, etc. A collapse of the air flow conveyed by the evaporator, i.e. a reduction or even interruption of the air throughput through the evaporator, during operation of the heat pump circuit is thus avoided. Furthermore, it can be expedient if in the area downstream of the air inlet side, in particular the air outlet side, preferably the rear area of ​​the evaporator, the transverse distance between any two adjacent heat exchange elements is at least 1.8 mm, in particular between 1.8 mm and 4 mm.This ensures that contaminants carried by the air into the area downstream of the air inlet side, in particular the air outlet side, preferably the rear, of the evaporator remain unproblematic there and that the air passages between the heat exchange elements do not become clogged over the operating life of the dishwasher.

[0013] If the distance between adjacent heat exchange elements gradually decreases as the air flows through the evaporator, a simple, parallel arrangement of the heat exchange elements can be achieved. The individual heat exchange elements do not need to run at an angle or curve toward each other.

[0014] If the air path through the evaporator is at least 8 centimeters long, there is enough space to create a wider area at the air inlet, especially at the front, for dirt removal, and to ensure optimized heat transfer (between the air forced through the evaporator and the working fluid) in a downstream area of ​​the evaporator, preferably at the outlet. The longer the path through the evaporator, the more favorable the heat transfer. On the other hand, there is very little space available for the heat pump components in a dishwasher, especially a household dishwasher. An evaporator length of at least 20 centimeters results in a significant improvement in efficiency.

[0015] To meet the described requirements, it is very advantageous to create an increased distance between adjacent heat exchange elements over the first quarter to the first half of the air's path through the evaporator, before creating a smaller distance in the subsequent, particularly outlet-side, preferably rear, area of ​​the evaporator. The heat exchange elements are expediently thermally connected to an evaporator line through which the working medium flows and protrude outwardly from this line. This increases the total surface area of ​​the evaporator through which air, particularly ambient air, can flow.

[0016] The evaporator is expediently designed such that the spaced-apart heat exchange elements extend transversely, in particular orthogonally, to the one or more line sections of the evaporator line, in particular a tubular line, through which the working medium flows. Structurally, it can be particularly advantageous if the spaced-apart heat exchange elements are arranged at least approximately parallel to one another, and in particular in a layered configuration. The one or more line sections crossing the heat exchange elements can be designed to be at least approximately rectilinear, for manufacturing convenience. They can expediently extend at least approximately parallel to one another in one or more installation planes.In particular, the evaporator line through which the working medium flows can be laid in a meandering manner such that its one or more meanders each comprise a forward line, preferably at least approximately straight, and a return line, preferably at least approximately straight, connected in series with the latter via a bend, as line sections.

[0017] In particular, it may be expedient for the heat exchange elements to be arranged upright, in particular at least approximately vertically upright. Then, the one or more line sections of the evaporator line through which the working medium flows, extending transversely, in particular orthogonally, to these elements, expediently run at least approximately horizontally.

[0018] Advantageously, the evaporator can be provided with a cuboid structure consisting of the one or more line sections of the evaporator line through which the working medium flows and the heat exchange elements, which enables a space-saving, compact accommodation of the evaporator, in particular in the appliance base of the household dishwasher.

[0019] According to an advantageous development of the invention, the heat exchange elements, together with the evaporator line through which the working medium flows, in particular the one or more meandering line sections of the evaporator line through which the working medium flows, can form a support structure. For this purpose, it can be particularly expedient if the one or more line sections of the evaporator through which the working medium flows penetrate the, preferably flat, heat exchange elements transversely, in particular at least approximately orthogonally, to their longitudinal extent. They traverse the air ducts or air passages provided between the heat exchange elements transversely, in particular at least approximately orthogonally, to their longitudinal extent. This advantageously results in an inherently stable structural unit of the evaporator.In particular, the meanders of the evaporator line and a package of a plurality of heat exchange elements can be coupled or held together via one or more plug-in connections. It may be advantageous if the one or more line sections of the evaporator line are inserted through openings or recesses, in particular elongated holes, in the heat exchange elements transversely, in particular perpendicularly, to their surfaces running in the direction of air flow, and thus the heat exchange elements are held as a package on the evaporator line by a plug-in connection that is simple to manufacture (and conversely, the evaporator line is held on the heat exchange elements).For this purpose, the heat exchange elements expediently have their openings at least approximately congruent to one another at those locations along their length where a forward-and-back, at least approximately straight, section of the respective meander of the evaporator line passes through all heat exchange elements together. The number of work steps required to manufacture the functional unit of the evaporator thus remains minimal.

[0020] The heat exchange elements are preferably each designed as flat elements, in particular as fins, which can absorb a large amount of heat from the air flowing around and / or through them. In particular, thin, heat-conducting sheets, preferably metal sheets, can be provided as heat exchange elements. The recesses or openings in the thin, flat sheets, through which the one or more line sections of the evaporator line are inserted, can be easily produced by punching out. In terms of production technology and material costs, it is advantageous if the heat exchange elements and the tubular evaporator line through which the working medium flows are made of aluminum. Aluminum also has a sufficiently good heat transfer coefficient.

[0021] According to an advantageous development, it may be expedient if a transverse spacer is provided between each two adjacent heat exchange elements at one or more points along their longitudinal extent, in particular where they are crossed by the tubular evaporator line. This allows the heat exchange elements to be held in position at predetermined transverse distances from one another, i.e., a defined transverse distance can be reliably and permanently maintained between each two adjacent heat exchange elements, so that an air passage of appropriate width in the transverse direction, in particular orthogonal to the longitudinal extent of the heat exchange elements, is permanently maintained between these two adjacent heat exchange elements. The heat exchange elements can thus be secured in position relative to the one or more line tubes of the evaporator tube as a finned package with defined transverse distances from one another.Any unintentional displacement of the heat exchange elements relative to one another, which could potentially lead to insufficient transverse spacing between the heat exchange elements or even to undesired contact between adjacent heat exchange elements with loss of air flow between them, is thus reliably avoided. In particular, the respective transverse spacer can be provided in a simple manufacturing manner by leaving an edge section of the material to be punched out, in particular sheet metal, of the heat exchange element where the opening is provided in the respective heat exchange element for the line section of the evaporator tube to be passed through it, and the remaining material is bent over as a tab in the transverse direction, i.e. transversely to the surface of the respective heat exchange element running in the air flow direction, in the direction of the transversely adjacent heat exchange element.Thus, a bent-over punched-out tab of the material of the respective heat exchange element can act as a transverse spacer, which saves material. If the heat exchange elements are penetrated by piping sections or sections for the working medium running perpendicular to their extension, heat transfer can be very effective, either directly from the air to the piping sections containing the working medium or indirectly via the heat exchange elements, especially if these are fin-like.

[0022] Particularly advantageously, fewer, particularly upright, heat exchange elements are provided in the air inlet-side, particularly front, area of ​​the evaporator, particularly on the air inlet-side front side of the evaporator, which the flowing air first encounters, than in the area of ​​the evaporator downstream of the air inlet-side area, particularly the air outlet-side, preferably the rear. The required greater spacing in the air inlet-side, particularly front, area is then created solely by removing or omitting heat exchange elements, particularly fins, in this area, which also results in material savings.

[0023] In this area, for example, every second fin may be missing. Or two out of three fins may be missing, so that only every third fin extends to the front end of the evaporator.

[0024] For example, it is possible that in the air inlet-side, particularly front, area of ​​the evaporator, particularly on the air inlet-side face of the evaporator, which the air flowing through it first encounters, only every second heat exchange element is present in its full vertical extent, at least in some areas. Alternatively, in the air inlet-side, particularly front, area of ​​the evaporator, particularly on the air inlet-side face of the evaporator, which the air flowing through it first encounters, only every second upright heat exchange element can be present at all.

[0025] The design and assembly are maximally simplified if all heat exchange elements are arranged parallel to each other, particularly vertically, as in previous solutions, despite the spacing variation according to the invention. A condensate collection device is particularly advantageously located in the lower area of ​​the evaporator, so that it can be quickly drained away and cannot contribute to further icing.

[0026] Furthermore, the collecting device can be emptied using a condensate pump.

[0027] When using R600a (isobutane) as the heat pump's working fluid, the internal diameter of the tubular evaporator line through which the working fluid flows is preferably greater than or equal to 5.5 mm. This minimum internal diameter of the evaporator line ensures that the R600a working fluid does not experience excessive pressure loss in the evaporator line, which would lead to an undesirably large reduction in the evaporation temperature of the R600a working fluid. This would result in a larger difference between the condensation temperature (in the condenser) and the evaporation temperature of the R600a working fluid (in the evaporator), making the heat pump less efficient.

[0028] 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.

[0029] The invention and its advantageous developments and further developments as well as their advantages are explained in more detail below with reference to drawings.

[0030] They show, in a schematic principle sketch:

[0031] Fig. 1 shows a schematic perspective view obliquely from the front of a household dishwasher shown here as an example, with a door that can be swung downwards and a base or base support for receiving functional elements in the lower area, in which a heat pump or heat pump arrangement for heating washing liquid during at least a partial washing phase of a dishwashing program to be carried out is additionally accommodated in a manner that is advantageous in terms of connection and space. Fig. 2 shows a merely exemplary, drawn-out perspective view of a heat pump in which, in the installed position, its evaporator, designed according to the design principle according to the invention, is located in the vicinity of a rear wall of the household dishwasher.

[0032] Fig. 3 is a schematic perspective view of the evaporator of Figure 2 constructed according to the inventive design principle, which has a stepped width of the flow area between upright fins, and

[0033] Fig. 4 is a plan view of the evaporator according to Figure 3.

[0034] Elements with the same function and mode of operation are provided with the same reference numerals in the figures.

[0035] Figure 1 shows an example of a dishwasher 1, in particular a household dishwasher.

[0036] The household dishwasher according to Figure 1 described below has, as a component of a partially outwardly open or closed appliance body 5, a washing container 2 for holding items to be washed or items to be cleaned, such as dishes, pots, cutlery, glasses, cooking utensils, and the like. The items to be washed can be arranged, in particular held, for example in dish baskets 11, in particular in a lower dish basket and in an upper dish basket arranged at a height above this, and / or in a cutlery drawer 10, and can be exposed to so-called washing liquor or washing water 24 therein in one or more partial washing phases of a dishwashing program to be carried out. The washing liquor or washing water 24 can be used as washing liquor or washing water.Rinse liquid 24 is preferably understood to mean fresh water and / or water circulating in particular during the rinse cycle of the household dishwasher, with or without detergent and / or rinse aid and / or drying agent, which comes into contact with the items to be washed. The rinse liquor 24 can additionally also be mixed to a greater or lesser extent with soiling from the ongoing rinse cycle, which is rinsed off the items to be cleaned during the execution of one or more partial rinse phases of the respective dishwashing program. If necessary, rinse liquid can also be used for the one or more partial rinse phases of the respective dishwashing program that was used in at least one partial rinse phase, such as the rinse phase of a previous dishwashing program, but remained relatively clean, and was then stored in a reservoir as process water. In particular, the rinse liquor can be pre-rinsed, ieBefore 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 V facing a user in the operating position. This front V can form part of a kitchen front consisting of adjacent kitchen units or, in the case of a stand-alone appliance 1, can also be without any connection to other units.

[0037] The loading opening of the washing tub 2, which in this exemplary embodiment is preferably at the front, can be closed in particular at this front side V by a (front) door or flap 3, the upper end of which can be pivoted forwards and downwards about a lower horizontal axis. This door 3 is shown in Figure 1 in a partially open position and then at an angle to the vertical. In its final closed position, however, it is at least almost upright and, as shown in Figure 1, can be pivoted forwards and downwards about a lower horizontal axis in the direction of arrow 4 to open it, so that in the fully open position (final opening position) it is at least almost horizontal. Other movements of the door, e.g. via a parallelogram or other multi-joint arrangement, are also possible.Of course, alternatively, a side-hinged door or a loading opening of the washing container 2 at the top with a door arranged essentially horizontally in its final closed position can also be provided.

[0038] The door can be provided with a decorative panel or door trim on the outside, i.e. on the side facing the user. In the exemplary embodiment in Figure 1, the front door 3 is provided with a decorative panel 6 on its outer and front side V, which is vertical in the closed position and faces the user, in order to thereby achieve a visual and / or tactile enhancement and / or adaptation to surrounding kitchen furniture. The household dishwasher 1 is designed here only as an example as a stand-alone or free-standing appliance on the floor B, or as a so-called partially integrated appliance and is installed on the floor B within a built-in niche between adjacent kitchen furniture below a kitchen worktop. In the latter case, the adjacent kitchen furniture and the kitchen worktop have been omitted from Figure 1 for the sake of simplicity of the drawing.

[0039] In the lower area of ​​the household dishwasher 1, below its washing container 2, there may be a base or a base support 12, in particular for accommodating functional elements, such as a pump (not shown) for circulating the washing solution 24 and / or a drain pump (not shown) for extracting the washing solution 24 from a pump sump fluidically connected to the washing container 2, and also a heat pump or heat pump arrangement 14 designed according to the functional principle according to the invention. This can be accommodated there in terms of space and connection technology. In Figure 1, this accommodation of the heat pump arrangement 14 in the base support or base 12 is merely symbolized by a dash-dotted rectangle. However, depending on the design of the household dishwasher, accommodation of the heat pump arrangement in the base is not mandatory, i.e.Deviating from the advantageous embodiment of Figure 1, the heat pump arrangement can also be arranged partially or completely outside the base 12, such as on the outside of a side wall and / or rear wall of the washing container 2.

[0040] In the exemplary embodiment of Figure 1, the appliance body 5 of the household dishwasher 1 has two opposing side walls S. A rear wall R is provided at the rear, which may also be perforated and allows access to the evaporator 20 of the heat pump 14.

[0041] In the exemplary embodiment according to Figure 1, the movable door 3 is assigned, in its upper region, an outer, front-side panel 8 which extends in the transverse or width direction Q of the dishwasher 1 and can comprise displays and / or operating elements and then also serves as a display and / or operating panel. Preferably in the region of its lower edge, as here in the exemplary embodiment of Figure 1, an access opening 7 accessible from the front side V for manually opening and / or closing the door 3 can expediently be provided. This access opening 7 is provided here, for example, only in the transverse center region of the door 3, although this is not mandatory. An access opening 7 extending in the transverse direction Q at least across almost the entire width of the household dishwasher is also possible, i.e., for example, over 50 to 60 centimeters in the case of a 60 cm wide household dishwasher.As an alternative to such a partially integrated or "stand-alone", i.e. free-standing, installable household dishwasher, whose front door has a control panel in its upper edge area with display and / or operating elements visible on the front when the front door is in the vertically closed position, the entire front of a so-called fully integrated household dishwasher can be covered by a cover such as a kitchen furniture panel. With this door variant, the control and / or display elements of a control panel can be provided, for example, on the upper outer edge of the front door, so that the control and / or display elements are only visible and / or accessible to a user on the upper edge of the door when the front door is in the open position. Other door variants are of course also possible depending on the type of dishwasher and / or setup or installation conditions.

[0042] 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 household dishwasher 1 does not have to stand directly on a floor B as in Figure 1, but can also be installed higher on the floorboard of a kitchen base unit or within another piece of kitchen furniture, or can be set up on a pedestal or a kitchen worktop with a height difference from the floor B. In particular, the height difference can be selected so that a user, for example,when loading or unloading the dish baskets, in particular the lower dish basket, of the dishwasher, or when refilling rinse aid into a dosing unit provided on the inner wall of the front door 3, only a slight or no bending movement is required when the front door 3 is brought into its at least approximately horizontal opening end position. The lower edge of the dishwasher 1 can then, in this installation or installation position raised relative to the floor B, preferably lie approximately 40 to 110 centimeters above the floor B. The vertical height (extension in the vertical direction H) of the household dishwasher 1 can also vary or be different depending on the type of construction and / or installation conditions.

[0043] In this exemplary embodiment, the washing compartment 2 is preferably delimited all around by a total of three fixed vertical walls 13 and two horizontal walls 13 when the door or flap is closed, one of which forms a ceiling (top) and another a floor (bottom) of the washing compartment 2. Adjacent to the front V facing the user in the transverse direction Q is a left, at least approximately vertically upright side wall 13 to the left, and opposite this to the right is a right, at least approximately vertically upright side wall 13. They are connected to one another at the rear by an at least almost vertically upright rear wall 13.

[0044] The heat pump or heat pump arrangement 14 of the household dishwasher 1 is shown in Figure 2 in an exemplary embodiment with its functional components as a compact structural unit. With its aid, the washing liquid present in the circulation pump circuit or hydraulic circuit of the household dishwasher 1 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 condenser 16, with which mechanical work can be performed on a working medium 17 circulating in the heat pump 14, for example a propane / butane mixture or R600a (isobutane). The compressor 16, in which the mechanical work on the working medium 17 is performed, is electrically driven.

[0045] In addition to the compressor 16, the heat pump or heat pump assembly 14 comprises, as functional units—which may, but do not have to, be structural units—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 sections or line sections 21 for conveying a working medium 17 that changes its state of aggregation during operation. 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.

[0046] In addition to the components mentioned, the heat pump arrangement 14 expediently comprises at least one air conveying device 29, which, viewed in its air conveying direction, is arranged upstream of the evaporator 20. The air conveying device 29, in particular a fan, ensures that, when the heat pump 14 is operated to heat dishwashing liquid during the respective partial dishwashing phase, in particular the cleaning and / or final rinsing phase of a dishwashing program to be carried out, ambient air 28 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 heat exchange elements 26, in particular fins, which are thermally conductively connected to these and protrude from these - here in the exemplary embodiment with a direction from front to back to the rear wall R of the household dishwasher 1 - whereby heat is extracted from the ambient air 28 and transferred to the working medium 17.The air conveying device 29 is expediently arranged in this embodiment such that, during its operation, ambient air 28 is sucked in from the space surrounding the dishwasher 1 through, for example, front-side ventilation slots 30 and / or through gaps, cracks, recesses and / or openings in the one or more walls of the base support or appliance base of the dishwasher and is preferably blown backwards (in the depth direction of the dishwasher) to the evaporator 20 and flows along its one or more, preferably meandering, line regions or line sections 33 through which the working medium can flow or through and / or along the heat exchange elements 26, in particular fins, projecting from these. In the conveying direction of the air conveying device 29 pointing from front to back (towards the rear wall R), after its passage through the evaporator 20, ieThrough the gaps between the line regions 33 of the evaporator 20 and / or between the heat exchange elements 26, in particular fins, which are thermally conductively connected to them and protrude therefrom, the ambient air cooled by the evaporator 20 can escape outwards into the environment of the dishwasher, preferably through a recess or opening in the rear wall R of the dishwasher 1. The heat pump 14 is also assigned at least one supply line 23 and one discharge line 22 (shown unconnected here) for washing liquid 24 that can be or is circulating in the household dishwasher 1, and an electrical connection option 25. By means of the electrical connection option 25, in particular the compressor 16 can be supplied with electrical energy for its operation and / or the air conveying device 39 for its operation.

[0047] Rinse liquid 24 flows via the supply line 23 from the circulation circuit or circulation pump circuit (not shown) of the household dishwasher into a heat transfer line or pipe section 50 which is in thermal contact with the condenser 18. The rinse liquid heated by the condenser 18 leaves the pipe section 50 via the discharge line 22. The condenser 18 and the heat transfer line section or pipe section 50 through which the rinse liquid 24 flows or (when the circulation pump 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 rinse liquid 24 flowing through the heat transfer section or pipe section 50, in particular pumped by the circulation pump of the household dishwasher.From the outlet of pipe section 50, the rinsing liquid 24 heated by the condenser 18 is returned via the discharge line 22 directly to the rinsing tank 2 or to it at another point in the circulation circuit. The rinsing liquid 24 flowing through the heat transfer device WT is symbolized in Figure 2 by a separate arrow.

[0048] In addition, the heat pump arrangement 14 can, in addition to the electrical connection option 25 and the connection options 22, 23 for the rinsing liquid 24, optionally comprise various sensors and a connection for a communication interface, in particular for a data bus - both not shown. The electrical connection 25 can - as shown by way of example in Figure 2 - in particular be part of an electrical module which optionally also comprises sensors and the communication interface connection, in particular the data bus connection. In the heat exchanger WT, the rinsing liquid 24 to be heated expediently passes through the heat transfer line section or pipe section 50 in the countercurrent principle to the working medium 17 flowing through the condenser 18. In this way, an efficient, i.e. highly effective, transfer of the heat from the working medium 17 to the rinsing liquid 24 is ensured in the heat exchanger WT.

[0049] This heat pump 14 can - as shown in Figure 2 - form an overall modular unit. For this purpose, at least the essential components 16, 18, 19, 20, 21 of the heat pump 14 and, if applicable, also the air conveying device 29 arranged upstream of the evaporator 20 can be mechanically fixedly arranged on a support unit 15 holding them, such as a support plate or a holding frame, so that a modular and easy-to-assemble unit is formed. These functional components of the heat pump 14 can be pre-assembled on the support unit 15 before installation in the dishwasher 1, filled with working medium 17 and either testable for function or, in particular, tested for function before installation. In particular, the heat pump 14 can be tested in advance for the tightness of its components 16, 18, 19, 20, 21 carrying the working medium 17.

[0050] In the version shown in Figure 2, the functional unit of the evaporator 20 is also designed as a structural unit, resulting in a coherent, more or less cuboid-like structure for this functional unit. In the heat pump 14 shown as an example in Figure 2, the installation position can be such that the evaporator 20 is located in the rear area in front of the rear side R of the dishwasher 1.

[0051] In this exemplary embodiment, the evaporator 20 comprises a plurality of adjacent, upright, flat, particularly lamellar, heat exchange elements 26, which extend in the air flow direction of the ambient air 28 flowing through the evaporator. In this exemplary embodiment, the air flow direction through the evaporator 20 runs from front to rear in the depth direction of the appliance base 12 toward the rear R of the household dishwasher 1.The thin-walled, flat heat exchange elements 26 form a finned package in which they are arranged as upright, edged fins at least approximately orthogonal to the direction of air flow of the ambient air 28 - here in the transverse direction Q of the household dishwasher - in a layered manner at a distance one behind the other, and each extend parallel to one another in the direction of air flow of the evaporator, specifically here in the depth direction of the appliance base 12 towards the rear R of the household dishwasher 1. Due to their upright, such as transverse-edged or edgewise arrangement, their upper and lower edges each point in the direction of air flow. These flat heat exchange elements 26 are surrounded by line regions or lines through which the working medium 17 flows, which run transversely, in particular orthogonally, to their longitudinal extent.The heat exchange elements 26 penetrate the tubular evaporator line sections 33 of the evaporator 20, forming a support structure. The heat exchange elements 26 are in heat-conducting contact with the tubular evaporator line sections 33 of the evaporator 20, which extend transversely, in particular orthogonally, to their longitudinal extension or to the air flow direction and through which the working medium 17 flows.

[0052] Open channels or air passages 27 are formed between the heat exchange elements 26, through which ambient air 28 drawn in by the air conveying device 29 can be blown to transfer heat to the working medium 17 flowing in the line sections 33 of the evaporator line. The line sections 33 of the tubular evaporator line, which penetrate the walls of the upright heat exchange elements 26, traverse the air channels or air passages 27 provided between the heat exchange elements 26 transversely, in particular at least approximately orthogonally, to their longitudinal extent.

[0053] The heat exchange elements 26 can, for example, be formed from upright metal sheets and ensure intensive thermal exchange with the ambient air 28 flowing in from the air conveying device 29. This incoming ambient air 28 therefore loses as much of its thermal energy as possible in the evaporator 20 and is simultaneously dried by condensing some of the moisture it carries on the heat exchange elements 26 and duct sections 27, which are colder than its air temperature. In particular, the path of the ambient air 28 through the evaporator 20, here the length L of the evaporator 20, is at least 8 centimeters, and even better, significantly more, for example, more than 20 centimeters, in order to enable effective transfer of heat from the ambient air 28 to the working medium 17 flowing in the duct sections 33.

[0054] The ambient air 28 is sucked in by the air conveying device 29, in particular a fan or a similar conveying device, for example through inlet slots 30 provided on the front side V of the dishwasher (see Figure 1) and / or through gaps, cracks, recesses and / or openings in one or more walls of the base support or appliance base 12 of the household dishwasher 1, and is fed to an air inlet-side surface 31, in particular the inlet-side end face, of the evaporator 20, which, as the first contact surface of the evaporator 20, comes into contact with this incoming air 28. In this exemplary embodiment, the air conveying device 29 blows ambient air 28 from front to back (towards the rear side R of the household dishwasher 1) through the air passages or air ducts 27, which are provided between the heat exchange elements 26, in particular fins, of the evaporator 20.

[0055] In the evaporator 20 designed according to the invention, the distance d1, d2 measured in the transverse direction between adjacent heat exchange elements 26 in the construction shown in Figures 2 - 4 varies, i.e. the channels or air passages 27 formed do not have the same width d1 or d2 over the entire length L of the evaporator 20, at least in part.

[0056] In the design shown here, the distance d1 between any two adjacent heat exchange elements 26 in the transverse direction to the air flow direction is greatest on the aforementioned front face 31 of the evaporator 20, which first comes into contact with the incoming ambient air 28. This is particularly useful because the incoming ambient air here contains the greatest proportion of dust, fluff, fibres and similar contaminants, so that the risk of blockage of the air ducts 27 is greatest in the front area BE of the evaporator 20. In addition, the incoming ambient air 28 also contains the greatest proportion of moisture here, and therefore there is a risk of the ducts 27 icing up in the area of ​​the front face 31 of the evaporator 20.Passages 27 are at their greatest due to contamination and moisture—with fatal consequences, because the air flow in the air flow direction downstream of the inlet-side area BE, particularly the outlet-side, here rear, area BA of the evaporator 20, would become too low or even collapse. The function of the heat pump 14 would then no longer be possible.

[0057] To counteract this, the transverse distance between any two adjacent heat exchange elements 26 is reduced as the ambient air 28 passes through the evaporator 20. This reduction can take place continuously or in one or more stages 32 (see plan view of Figure 4). Here, the drawing shows a single-stage distance reduction from the larger distance d1 between any two adjacent heat exchange elements 26 in the transverse direction to the air flow direction on the front end face 31 and inlet-side region BE to a smaller distance d2 between any two adjacent heat exchange elements 26 in the transverse direction to the air flow direction in the outlet-side, here rear, region of the evaporator 20.This means that, as the ambient air 28 passes through the evaporator 20, the distance between any two adjacent heat exchange elements in the transverse direction to the air flow direction decreases gradually from d1 to d2, where d1 > d2 applies.

[0058] Here, exactly one level 32 is provided to reduce the distance.

[0059] This stage 32 can be achieved, as illustrated in Figures 3 and 4, in that fewer (complete) upright heat exchange elements 26 are provided in the air inlet side or here front area BE of the evaporator 20, i.e. in the vicinity of the front surface 31, which the ambient air 28 flowing through first encounters, than in the air outlet side or here rear area BA.

[0060] For example, in the air inlet side or here the front area of ​​the evaporator 20, which is hit first by the air flowing through 28, at least in some areas only every second heat exchange element 26 can be present in its full vertical extent, for example in such a way that every second heat exchange element 26 has recesses and the width of the channels 27 is thus increased in the area of ​​the recesses. Such a version is not shown here. Alternatively, as shown in Figures 2, 3 and 4, in the air inlet side, here the front area BE of the evaporator 20, which is hit first by the ambient air flowing through 28, only every second upright heat exchange element 26 of the heat exchange elements 26 provided in the air outlet side, here the rear area BA, can be present. In this air inlet orIn the air inlet side area BE, the distance d1 between two heat exchange elements 26 adjacent to one another in the transverse direction is thus twice as large as the distance d2 in the air outlet or air outlet side, here in particular the rear area BA.

[0061] Alternatively, it would also be possible, for example, to omit two (or more) of three heat exchange elements 26 in the front area, so that the distance d1 would then be three times (or more) as large as the distance d2.

[0062] In all of the above cases—as well as with other recess types of the heat exchange elements 26—all heat exchange elements 26 can be arranged parallel to one another, which is the simplest and most stable solution from a manufacturing perspective. To create different spacings d1, d2, etc., it is not necessary to deviate from the parallelism of the upright heat exchange elements 26 at any point. The manufacture of the evaporators 20 can thus continue to be easily handled by production robots.

[0063] The precisely one step 32 for varying the distance between the large distance d1 and the smaller distance d2, as shown here by way of example, can be arranged at various longitudinal points along the length L of the evaporator 20 (viewed in the direction of flow). Here, in the exemplary embodiment of Figures 2, 3 and 4, it is positioned such that over the first quarter to the first half of the path of the air 28 through the evaporator 20, i.e. over the first quarter to the first half of the length L of the evaporator 20, an increased distance d1 is created between adjacent heat exchange elements 26, before the narrower or smaller distance d2 then sets in between any two transversely adjacent heat exchange elements 26 for improved heat transfer.

[0064] A condensate collecting device can be provided below the evaporator 20, such as an open tray which can be emptied, for example, via a condensate pump, in order to be able to quickly remove the liquid condensed from the incoming air 28 so that it cannot further contribute to the saturation with liquid in the area critical for icing.

[0065] According to an advantageous development of the invention, the heat exchange elements 26, together with the evaporator line through which the working medium 17 flows, in particular the one or more meandering line sections 33 of the evaporator line through which the working medium 17 flows, can form a support structure. For this purpose, it can be particularly expedient if the one or more line sections 33 of the evaporator 29 through which the working medium 17 flows penetrate the preferably flat heat exchange elements 26 transversely, in particular at least approximately orthogonally, to their longitudinal extent. They traverse the air ducts or air passages 27 provided between the heat exchange elements 26 transversely, in particular at least approximately orthogonally, to their longitudinal extent. This advantageously results in an inherently stable structural unit of the evaporator 20.In particular, the meanders of the evaporator line and a package of a plurality of heat exchange elements 26 can be coupled or held together via one or more plug-in connections. It may be advantageous if the one or more line sections 33 of the evaporator line are inserted through openings or recesses AS (see Figure 2), in particular elongated holes, in the heat exchange elements transversely, in particular perpendicularly, to their surfaces running in the air flow direction, and thus the heat exchange elements 26 are held as a package on the evaporator line by a plug-in connection that is simple to manufacture (and conversely, the evaporator line is held on the heat exchange elements).For this purpose, the heat exchange elements 26 expediently have their openings AS at least approximately congruent to one another at those longitudinal locations along their length where a forward-and-back, at least approximately straight line section 33 of the respective meander of the evaporator line passes through all heat exchange elements 26 together. The number of work steps for producing the functional unit of the evaporator 20 thus remains low.

[0066] If necessary, it may be expedient if a transverse spacer is provided between each two adjacent heat exchange elements 26 at one or more points along their longitudinal extent, in particular where these are crossed by the line sections 33 of the tubular evaporator line. Such transverse spacers are visible in Figure 3 and are designated by AH. By means of these transverse spacers AH h, the heat exchange elements 26 can be held in position with predetermined transverse distances such as d1 or d2 from one another, i.e. a defined transverse distance such as d1 or d2 can be reliably and permanently maintained between each two adjacent heat exchange elements 26, so that an air passage 27 of corresponding width in the transverse direction, in particular orthogonal direction, to the longitudinal extent of the heat exchange elements 26 is permanently maintained between these two adjacent heat exchange elements 26.The heat exchange elements 26 can thus be secured in position relative to the one or more conduit tubes 33 of the evaporator tube as a finned package with defined transverse spacings from one another. This reliably prevents unwanted displacement of the heat exchange elements 26 relative to one another, which could potentially lead to insufficient transverse spacing between the heat exchange elements 26 or even to undesired contact between adjacent heat exchange elements, resulting in the loss of the air passage 27 between them.

[0067] In particular, the respective transverse spacer AH can be provided in a simple manufacturing manner by leaving an edge portion of the material to be punched out, in particular sheet metal, of the heat exchange element 26 where the opening is provided in the respective heat exchange element 26 for the line section 33 of the evaporator tube to be passed through it, and by bending the remaining material in the transverse direction, i.e., transversely to the surface of the respective heat exchange element 26 running in the air flow direction, in the direction of the transversely adjacent heat exchange element, as a tab. Thus, a bent-over punched-out tab of the material of the respective heat exchange element can function as a transverse spacer, which saves material.

[0068] In terms of production technology and material costs, it is advantageous if the heat exchange elements and the tubular evaporator line through which the working fluid flows are made of aluminum. Aluminum also has a sufficiently good heat transfer coefficient.

[0069] When using R600a (isobutane) as the working medium 17 of the heat pump 14, the inner diameter of the tubular evaporator line through which the working medium 17 flows is preferably greater than or equal to 5.5 mm. This minimum inner diameter of the evaporator line ensures that the working medium R600a does not experience excessive pressure loss in the evaporator line, which would lead to an undesirably large reduction in the evaporation temperature of the working medium R600a, resulting in a greater difference between the condensation temperature (in the condenser) and the evaporation temperature of the working medium R600a (in the evaporator), making the heat pump less efficient.

[0070] If the air-to-heat pump 14 is also to be used to dry the wash cabinet air during the drying phase of the respective dishwashing program being run, wash cabinet air to be dehumidified is passed through the evaporator instead of ambient air to cool it and condense moisture from it. The air conveying device 29 and the evaporator 20 are then expediently inserted into a recirculation duct through which air to be dehumidified is drawn from the wash cabinet of the washing container by means of the air conveying device 29, blown through the evaporator 20 to cool and condense moisture, and then the thus drier wash cabinet air is transported back into the wash cabinet. If necessary, at least one condenser section of the heat pump can be provided in the recirculation circuit downstream of the evaporator 20 in the air flow direction to reheat the cooled air before it is blown into the wash cabinet.The dried and reheated air can then absorb moisture again in the dishwashing chamber or from the moist items to be dried that are stored there.

[0071] In a modification of the exemplary embodiment of the evaporator 20 illustrated in Figures 2 - 4, through which air 28 is blown in the depth direction towards the rear R of the domestic dishwasher, it is also possible, with a correspondingly modified structural arrangement or orientation and / or design of the evaporator, for air to flow through said evaporator in a different direction, from which heat is transferred to the working medium 17. For example, the evaporator can be aligned laterally, i.e. in the transverse direction, with its air outlet side region, so that during a partial wash phase of a dishwashing program to be carried out with wash liquid that is to be heated by the heat pump, the ambient air flowing through it exits in the region of one of the long side walls of the domestic dishwasher.

[0072] List of reference symbols

[0073] 1 dishwasher,

[0074] 2 rinsing containers,

[0075] 3 doors,

[0076] 4 Swivel direction,

[0077] 5 device body,

[0078] 6 decorative panel,

[0079] 7 access opening,

[0080] 8 outer aperture,

[0081] 10 cutlery drawer,

[0082] 11 dish basket,

[0083] 12 bases,

[0084] 13 walls of the rinsing tank,

[0085] 14 heat pump,

[0086] 15 carrier unit,

[0087] 16 compressor,

[0088] 17 Working medium,

[0089] 18 condensers,

[0090] 19 Expansion facility,

[0091] 20 evaporators,

[0092] 21 management areas,

[0093] 22 supply line,

[0094] 23 Derivative,

[0095] 24 rinsing fluid,

[0096] 25 electrical connection options,

[0097] 26 heat exchange elements,

[0098] 27 channels for air,

[0099] 28 air flowing through,

[0100] 29 fan,

[0101] 30 inlet slots,

[0102] 31 air inlet side, especially front, surface of the evaporator, 32 stage,

[0103] 33 pipe sections in the evaporator,

[0104] 50 through which rinsing liquid flows or can flow

[0105] Pipe section

[0106] AS breakthrough, especially slotted hole

[0107] B floor,

[0108] BE air inlet side of the evaporator

[0109] BA air outlet side area of ​​the evaporator d1 larger distance, d2 smaller distance

[0110] H vertical height,

[0111] L length of the evaporator,

[0112] R back,

[0113] Q transverse direction,

[0114] V front,

[0115] WT heat transfer device or heat exchanger for

[0116] Heating of rinsing liquid

Claims

Patent claims 1. Dishwasher (1), in particular a household dishwasher, with at least one heat pump (14) which comprises, as functional units, at least a compressor (16), a condenser (18), an expansion element (19) and an evaporator (20), which are connected to one another via line regions (21) for conveying a working medium (17) which changes its state of aggregation during operation, characterized in that the functional unit of the evaporator (20) comprises a plurality of adjacent, in particular upright, heat exchange elements (26), between which air (28) can be passed for the purpose of dissipating heat to the working medium (17), wherein the distance (d1, d2) between adjacent heat exchange elements (26) varies along the path of the air (28) through the evaporator (20).

2. Dishwasher (1) according to claim 1, characterized in that on an air inlet-side, in particular front, surface (31) of the evaporator (20), which first has contact with the incoming air (28), the distance (d1) between adjacent heat exchange elements (26) is greatest.

3. Dishwasher (1) according to one of claims 1 or 2, characterized in that the distance (d1, d2) between each two adjacent heat exchange elements (26) is reduced via the path of the air (28) through the evaporator (20).

4. Dishwasher (1) according to at least one of claims 1 to 3, characterized in that that a larger, in particular a transverse distance (d1 > 2 d2) larger by at least a factor of two, is provided over the path of the air (28) through the evaporator (20) in an air inlet-side, in particular front, region (BE) of the evaporator (20) between each two adjacent heat exchange elements (26) than in a region (BA) of the evaporator (20) downstream of the air inlet-side region (BE), in particular on the air outlet side, preferably rear.

5. Dishwasher (1) according to claim 4, characterized in that in the region (BA) of the evaporator (20) downstream of the air inlet-side region (BE), in particular the air outlet-side, preferably rear, the transverse distance (d2) between any two adjacent heat exchange elements (26) is at least 1.8 mm, in particular between 1.8 mm and 4 mm.

6. Dishwasher (1) according to at least one of claims 1 to 5, characterized in that the distance (d1, d2) between adjacent heat exchange elements (26) is reduced step by step (step 32) via the path of the air (28) through the evaporator (20).

7. Dishwasher (1) according to at least one of claims 1 to 6, characterized in that the path of the air (28) through the evaporator (20) is at least 8 centimeters long.

8. Dishwasher (1) according to at least one of claims 1 to 7, characterized in that over the first quarter to the first half of the path of the air (28) through the evaporator (20) an increased distance (d1) is created between adjacent heat exchange elements (26).

9. Dishwasher (1) according to at least one of claims 1 to 8, characterized in that that the heat exchange elements (26) are thermally connected to an evaporator line (33) of the evaporator (20) through which the working medium (17) flows and protrude outwards relative to this.

10. Dishwasher (1) according to at least one of claims 1 to 9, characterized in that the heat exchange elements (26) are arranged in layers at least approximately parallel to one another, and in that one or more line sections (33) of the evaporator line of the evaporator (20) through which the working medium (17) flows run transversely, in particular orthogonally, to the heat exchange elements (26).

11. Dishwasher (1) according to at least one of claims 1 to 10, characterized in that the heat exchange elements (26) together with the one or more line sections (33) of the evaporator line form a holding structure.

12. Dishwasher (1) according to at least one of claims 1 to 11, characterized in that the heat exchange elements (26) are designed as fins, in particular upright metal sheets.

13. Dishwasher (1) according to at least one of claims 1 to 12, characterized in that the heat exchange elements (26) are penetrated by line regions (33) for working medium (17) running transversely to their extent.

14. Dishwasher (1) according to at least one of claims 1 to 13, characterized in that in the air inlet side, in particular front, area (BE) of the evaporator (20), fewer, in particular upright, heat exchange elements (26) are provided than in a region of the evaporator (20) arranged downstream of the air inlet side area (BE), in particular on the air outlet side, preferably rear.

15. Dishwasher (1) according to at least one of claims 1 to 14, characterized in that in the air inlet side, in particular front, area (BE) of the evaporator (20), at least in some areas only every second heat exchange element (26) is present in its full height extension.

16. Dishwasher (1) according to at least one of claims 1 to 15, characterized in that in the air inlet side, in particular front, area of the evaporator (20), only every second, in particular upright, heat exchange element (26) is present.

17. Dishwasher (1) according to at least one of claims 1 to 16, characterized in that all heat exchange elements (26) are arranged parallel to one another, in particular vertically.

18. Dishwasher (1) according to at least one of claims 1 to 17, characterized in that a collecting device (34) for condensate is arranged below the evaporator (20).

19. Dishwasher (1) according to claim 18, characterized in that the collecting device (34) can be emptied via a condensate pump.

20. Dishwasher (1) according to at least one of claims 1 to 19, characterized in that when using R600a (isobutane) as the working medium (17) of the heat pump (14), the inner diameter of the tubular evaporator line (33) through which the working medium (17) flows is greater than or equal to 5.5 mm.

21. Dishwasher (1) according to at least one of claims 1 to 20, characterized in that the heat exchange elements (26) and the tubular evaporator line (33) through which the working medium (17) flows are made of aluminum.

22. Dishwasher (1) according to at least one of claims 1 to 21, characterized in that a transverse spacer (AH) is provided between each two adjacent heat exchange elements (26) at one or more points along their longitudinal extension, in particular where they are crossed by the tubular evaporator line (33).

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