EP3410914A1

EP3410914A1 - Domestic dishwasher and method for operating one such

Info

Publication number: EP3410914A1
Application number: EP17700848.9A
Authority: EP
Inventors: Jochen Riedinger; Martin Heinle; Kai Paintner
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2016-02-04
Filing date: 2017-01-20
Publication date: 2018-12-12
Also published as: WO2017133907A1; DE102016201688A1

Abstract

The invention proposes a method for operating a domestic dishwasher (1) within the context of a dishwashing program, wherein the dishwashing program comprises a sub-program step, in particular cleaning step, during which washable items (3) arranged in an accommodating chamber (2) of the domestic dishwasher (1) are subjected to the action of heated dishwashing liquor, and wherein the dishwashing program comprises at least one drying step, which comes at a later point in time than the sub-program step, in particular cleaning step, and during which air flows into the accommodating chamber (2), absorbs moisture there from the items (3), in order to dry the latter, and finally leaves the domestic dishwasher (1). According to the invention, the domestic dishwasher (1) comprises a heat exchanger (4), with a heat-accumulator medium (5), and also a heat-pump arrangement (6). Heat is extracted from the heat-accumulator medium (5), with the aid of the heat-pump arrangement (6), before and/or during the drying step, wherein air is directed through the heat exchanger (4) during the drying step and before it is discharged to the surroundings of the domestic dishwasher (1), and wherein heat is extracted from the water vapour entrained by the air in the region of the heat exchanger (4) and said heat is transmitted, in turn, to the heat-accumulating medium (5), and therefore the water vapour, in the region of the heat exchanger (4), is at least partially condensed. A domestic dishwasher for implementing the method is described in addition.

Description

Household dishwasher and method for

Operate such

The invention relates to a method for operating a domestic dishwasher as part of a washing program. In addition, a household dishwasher for cleaning items to be washed is described.

Domestic dishwashers are known in the art and serve in principle the cleaning or washing and subsequent drying of contaminated items, such as crockery or cutlery. For drying the items to be washed, such household dishwashers have a drying system for the cleaned item to be cleaned, in which the water absorbs the water which adheres to the cleaned items, so that the item to be washed is dried. The now moist air leaves the household dishwasher in some types of drying systems and enters their surroundings, for example in a kitchen. As a rule, this steam-laden air finally flows over the kitchen's upper and / or working surfaces, whereby the water vapor entrained in the air condenses on it and precipitates as moisture. This moisture forms a breeding ground for bacteria, molds, or the like, so that it comes at these points to a microbial load, which is extremely undesirable, especially in kitchens, as associated with the health risks. In addition, moisture can damage the surfaces. In particular, if wood components such as e.g. Worktops made of pressed wood fibers are affected, they can be damaged by the moisture. The object of the present invention is to counteract these disadvantages.

The object is achieved by a method for operating a domestic dishwasher and by a domestic dishwasher according to the independent claims. Advantageous embodiments and further developments of the method according to the invention for operating the domestic dishwasher and the domestic dishwasher itself are explained in the subclaims and the following description. A method for operating a domestic dishwasher as part of a wash program is initially proposed, wherein the wash program includes, inter alia, a partial program step, in particular a cleaning step, while heated or heated wash liquor or dishwashing liquid is applied to the washware arranged in the receiving space of the wash container of the domestic dishwasher. The rinsing liquor in the cleaning step is preferably a mixture of heated water and a rinsing or cleaning agent, or in the final rinse step a mixture of heated water and a rinse aid. If appropriate, the rinsing liquor may also be unheated, ie cold, fresh water, for example in the pre-rinsing step preceding the cleaning step of the rinsing program, or in an intermediate rinsing step which may be inserted between the cleaning step and the subsequent rinsing step of the rinsing program. During the respective part program step, in particular cleaning step, during which rinsing liquid or rinsing liquor i, receiving space is sprayed by one or more spraying devices, the rinsing liquor receives dirt particles from the items to be rinsed or washed, so that the dirt particles are removed from the items to be washed. During the washing program and in time after the one or more liquid-conducting partial program steps, in particular after the cleaning step, a drying step is followed by a washing program, during which fresh air or outside air flows into the receiving space. Of course, between the cleaning step and the drying step of the washing program, if necessary, one or more further steps, for. A rinse step and / or intermediate rinse step. During the drying step, the air in the receiving space absorbs moisture from the previously treated with heated rinse wash ware to dry it. The moisture on the dishes still has such an elevated temperature that they easily evaporate and can be absorbed by the passing air.

According to the invention, the household dishwasher now comprises a heat exchanger with a heat storage medium and a heat pump arrangement. In this case, the heat storage medium with the aid of the heat pump assembly before the drying step heat (ie heat energy), in particular in a partial program step to be heated with rinsing water such as the cleaning step, withdrawn. The heat can be withdrawn from the heat storage medium additionally or alternatively also during the drying program-concluding drying step.

The heat storage medium of the heat exchanger preferably has a high specific heat storage capacity and / or a high enthalpy of fusion (preferably at least 300 kJ / kg). The heat storage medium can be, for example, a liquid, in particular water or a liquid comprising water.

According to an advantageous embodiment of the invention, the heat exchanger comprises a storage tank for the heat storage medium, in particular water.

The storage tank may be formed according to a first expedient variant as a closed container. The heat storage medium can thus be present in a separate storage container of the heat exchanger so that it is arranged in a closed system and, for example, no direct contact with the air, that is, process air from the receiving space. As a result, the heat storage medium always remains clean in an advantageous manner. Such a means, preferably fluid such as salt water or a gas or gas mixture, can be used as a heat storage medium in such a closed storage container, which is unsuitable as a rinsing liquor, ie treatment liquid in the receiving space of the rinsing container for washing the items to be cleaned there is. Alternatively, according to a second expedient variant of the heat exchanger in a double function as a heat storage tank for removing heat energy from the heat storage medium stored in it, in particular water, through the heat pump assembly and at the same time as a removal tank or filling tank for supplying treatment liquid into the receiving space of the Spülbehälters the Haushaltsgeschirrter. Dishwasher be formed. The heat storage medium, in particular storage water, from this heat exchanger is thus used at least partially as a treatment liquid in the receiving space in the respective liquid-conducting partial program step of a washing program. Due to its dual function as a heat exchanger and filling tank space in the dishwasher is advantageously saved, ie it is not necessary to provide space for a separate tank with heat storage medium and space for a separate tank with treatment liquid or process liquid, especially fresh water, within the dishwasher. It can be expedient, in particular, if the heat exchanger is formed by a container in which water, in particular fresh water, as heat storage medium and treatment liquid, via a supply line, in particular from a water supply network, can be filled, and from the outlet side via a discharge water as the treatment liquid or process fluid can be fed into the receiving space of the washing container of the dishwasher. The heat exchanger is therefore preferably operated here as an open tank with a water inlet and a water outlet. If per wash program, the heat storage medium in the tank or container of the heat exchanger is at least partially or completely changed, ie the container stored there heat storage medium partially or completely removed and filled with fresh heat storage medium, especially fresh water, so the risk of unwanted contamination the container of the heat exchanger largely avoided. Also, this change of the heat storage medium can be beneficial for the thawing of any ice that has formed in the storage tank from the heat storage medium during the respective active phase of operation of the heat pump assembly where heat is removed from the heat storage medium. Because the temperature and thus the thermal energy content of the storage tank newly supplied heat storage medium such as fresh water is usually higher than the temperature and the heat energy content of the storage container to ice solidified heat storage medium.

In addition, in a drying system of the domestic dishwasher in which process air is transported out of the receiving space, in particular via a connected to an air outlet of the receiving space air duct preferably by means of a blower, and delivered to the environment of the dishwasher during the drying step of the respective washing program, according to an advantageous Continuing a section of this air duct on an outer wall of the filled with the heat storage medium container or storage container, preferably thermally contacting, pass or pass through the container. In particular, it may be favorable if a partial area or the total area of a wall of the storage container forms or replaces a wall section of the air channel, so that the process air exiting from the receiving space on a wall of the storage tank or storage container filled with the heat storage medium directly, ie directly contacting can vorbeischreichen.

Expressed in general terms, the fact that the air duct is thermally coupled to the storage tank at least along part of its course results in effective heat transfer between the heat storage medium of the storage tank and the process air led out of the receiving space in a simple manner. The process air and the heat storage medium remain materially separated from each other.

It may be expedient, if appropriate, if the heat exchanger is attached on the outside to a wall, in particular side wall, of the washing container of the domestic dishwasher, and in particular a thermal insulation layer or thermal barrier is provided between the heat exchanger and the wall of the washing compartment. As a result, a heat transfer short circuit between the storage container of the heat exchanger and the receiving space of the washing container can be largely avoided. At the same time, the storage container nevertheless serves as a thermal energy sink for heat loss, which escapes from the rinsing container in spite of the thermal insulation layer.

The heat pump assembly further includes a refrigerant in its piping circuit. The refrigerant in the line loop of the heat pump assembly and the heat storage medium in the heat exchanger are separated from each other or have no direct contact with each other. However, between the refrigerant and the heat storage medium, a heat flow can form, d. H. Heat can be exchanged between the refrigerant and the heat storage medium.

In addition, the heat pump assembly includes a compressor or compressor for the refrigerant. With the help of the compressor that is in the compressor during operation of the

Heat pump assembly entering gaseous refrigerant compresses, where it heats up. Furthermore, the heat pump arrangement comprises a condenser, in which the heated gaseous refrigerant condenses again and thereby releases heat which, for example, by means of a thermal transfer means such as a heat exchanger. shear elements can be used for heating the rinsing liquor. Subsequently, the liquefied refrigerant is expanded by means of a throttle and finally passes into an evaporator of the heat pump arrangement, in which it passes under heat absorption again in the gaseous state, and then again to the compressor to be supplied to the.

In the context of the invention, it is now provided that the heat required for the evaporation of the refrigerant comes from the above-mentioned heat storage medium of the heat exchanger, this is thus withdrawn. The cooled after passing through the said throttle refrigerant thus cools as a result, the heat storage medium.

The refrigerant and the heat storage medium remain advantageously separated from each other. This can be done, for example, by means of a pipeline through which the refrigerant flows, with the refrigerant being conducted through the heat storage medium in the pipeline (the pipeline thus penetrates, for example, a storage volume having the heat storage medium). Through the pipe heat transfer is given in particular from the heat storage medium of the heat exchanger to the refrigerant of the heat pump assembly. During the drying step and before leaving the domestic dishwasher, process air is passed through the heat exchanger. In this case, the process air is that which originates from the receiving space of the washing container of the domestic dishwasher and has taken up the moisture of the items to be washed there. Heat is withdrawn from the heat exchanger via the water vapor entrained in the process air in the area of the heat exchanger. This heat is in turn transmitted to the (previously during the respective part program step heated with rinse liquor) using the heat pump assembly cooled heat storage medium. The water vapor in the process air in the region of the heat exchanger condenses at least partially. As a result, the process air leaving the household dishwasher is deprived of moisture. As a result, the moisture entrained by the process air is largely prevented from condensing on surfaces or other objects of the premises (eg, a kitchen) surrounding the domestic dishwasher, making them wet or moist, and / or forming a breeding ground for microorganisms. In summary, the essence of the present invention is therefore to remove heat from a heat storage medium of a heat exchanger of a domestic dishwasher with the aid of a heat pump and to bring the cooled heat storage medium into heat-conducting contact with the moist process air coming from the receiving space of the domestic dishwasher to extract water from the water To condense process air and dry the process air before it leaves the household dishwasher, especially in the environment at their installation. The condensed water vapor can be removed from the domestic dishwasher, for example, via a waste water outlet, via which the rinsing liquor is also removed. An introduction into the recording room would be conceivable.

According to a development of the invention, it is advantageous if the water content of the process air flowing out of the domestic dishwasher is reduced by means of the heat exchanger to a maximum of 50 g of water / m ^{3 of} air. Preferably, the water content is reduced to a maximum of 15 g of water / m ^{3 of} air. The remaining water content of the process air leaving the domestic dishwasher finally ensures that no further water vapor condensation occurs on surfaces of the premises surrounding the domestic dishwasher. A moisture penetration and thus material damage to a worktop above the dishwasher or other objects, in particular furniture parts, in the environment of the dishwasher is thus largely avoided. Bacteria, molds, or similar This effectively removes the nutrient medium.

According to an advantageous development, heat can be extracted from the heat storage medium by means of an evaporator of the heat pump arrangement during a partial program step with the wash liquor or wash liquor to be heated, for example the cleaning step, wherein the heat can be transferred to the wash liquor. In the evaporator, the refrigerant is evaporated, absorbing heat. Alternatively, the refrigerant does not have to be evaporated. In the case of a gaseous refrigerant, expansion of the refrigerant may be sufficient while it also absorbs heat. In any case, heat flows from the heat storage medium to the refrigerant. This removes heat from the heat storage medium which is then stored in the refrigerant. is chert. The heat can be used to heat the rinsing liquor, so that the heat is used meaningfully again. In particular, this means that the rinsing liquor no longer needs to be heated, or at least only to a small extent, by a separate electric heater. This reduces the energy consumption of the household dishwasher.

According to an advantageous development, during the drying step, incoming outside air flowing into the receiving space of the washing container of the domestic dishwasher can be heated prior to contact with the items to be washed. A heated air can absorb more water vapor than a cooler air. This allows the items to be washed faster with the heated air. The heating can be done for example by means of an electric heating element, the z. B. in the region of an air inlet of the domestic dishwasher or in a connecting the air inlet and the receiving space of the domestic dishwasher channel is arranged.

According to an advantageous development, the air flowing into the receiving space from the outside (fresh air or fresh air) is heated by supplying heat to this air by means of a heat exchanger which becomes free during operation of the heat pump arrangement in the region of the condenser of the heat pump arrangement. In the condenser, for example, the refrigerant can condense, in particular it is converted from the gaseous to the liquid state of aggregation, during which it cools down. The heat emitted in this case is transferred to the incoming air. Thus, a heat cycle in the heat pump assembly can be closed and the energy efficiency of the domestic dishwasher can be improved. Additionally or alternatively, the incoming air can also be heated with a (preferably different from a heat pump), preferably electric, heating element. Finally, it is also conceivable that the incoming air is not heated. In this case, it is advantageous if the wash ware is heated in a rinse step preceding the drying step in order to ensure that the moisture adhering to the ware vaporises or evaporates during the drying step and is thereby absorbed by the air (process air) in the receiving space can be. Preferably, the heating of the items to be washed takes place with the aid of previously heated rinse liquor (which may in this case comprise a rinse aid). Preferably, during the drying step, the air (process air) is moved by means of a fan from the receiving space into and / or through the heat exchanger and finally out of the domestic dishwasher. Furthermore, the heat pump arrangement preferably comprises the above-mentioned compressor, wherein the speed of the fan and / or the power of the compressor can be adjusted depending on the humidity of the air leaving the heat exchanger. The household dishwasher thus preferably comprises a sensor in the region of the heat exchanger, in the region between the heat exchanger and an air outlet, in particular the washing container, the domestic dishwasher (can escape through the air from the domestic dishwashing machine), or in the region of said air outlet.

The sensor is preferably designed to detect the air humidity or the dew point temperature of the air. The speed of the fan and / or the power of the compressor are preferably varied as a function of the respective detected variable (only one or both variables can be taken into account). It may also be advantageous if a corresponding sensor is also arranged outside the domestic dishwasher and also its measurement signal is used as the basis for changing the speed of the fan and / or the power of the compressor. For example, it would be conceivable to regulate the speed of the fan and / or the power of the compressor such that the dew point temperature or humidity of the air leaving the household dishwasher, i. Process air is always lower than the dew point temperature or the humidity of the domestic dishwasher immediately surrounding air. As a result, condensing of water vapor still contained in the process air leaving the domestic dishwasher to the household dishwasher is largely avoided or effectively prevented.

Further proposed is a domestic dishwasher for cleaning items to be washed with a receiving space for receiving the items to be cleaned. In particular, the household dishwasher has a heat exchanger with a heat storage medium. The heat storage medium is preferably water or a water-containing substance, for example a saline solution.

Furthermore, the household dishwasher comprises a Wärmepumpenanord- tion, with the help of which heat from the heat storage medium to a circulating during operation of the household dishwasher in the domestic dishwasher washing water is transferable. By means of the heat pump arrangement, heat can be transferred from the heat storage medium to the rinsing liquor in a particularly energy-saving manner. In particular, the heat pump assembly includes the above-described components compressor, condenser and throttle.

In addition, the heat pump arrangement comprises an evaporator which is arranged in the region of the heat exchanger such that heat can be transferred from its heat storage medium to the evaporator. The evaporator is flowed through by a refrigerant which absorbs the heat released by the heat transfer medium or heat storage medium and thereby evaporates. As a result, so the heat transfer medium of the heat exchanger can be cooled with the aid of the evaporator. According to the invention, the domestic dishwasher further comprises a receiving space and the heat exchanger connecting air duct and a fan. With the help of the fan, air (process air) can be moved from the receiving space via the air duct into or through the heat exchanger. In addition, the domestic dishwasher has a downstream of the heat exchanger air outlet. Through the air outlet, the air dehumidified by means of the heat exchanger leaves the heat exchanger and enters the environment, for example in a kitchen.

By means of this embodiment of the domestic dishwasher, the air passed through the receiving space during a drying step (the water content of which is increased when the warm items to be washed pass through) can now be cooled in the area of the heat exchanger. As a result, the water vapor entrained by the air at least partially condenses, so that the absolute water content of the air is reduced. When the air thus dried (exhaust air) finally leaves the household dishwasher, condensation of moisture on surfaces of the premises surrounding the domestic dishwasher is largely avoided. Moisture-related damage to these surfaces or the formation of a nutrient medium for microorganisms are thus reliably prevented. The heat exchanger preferably comprises a closed receptacle in which the heat transfer medium or heat storage medium is located. Preferably, said air duct passes through the heat exchanger in such a way that it is at least partially bounded by one or more walls of said receptacle, which in turn is in direct contact with the heat transfer medium.

According to an advantageous development of the evaporator is at least partially surrounded by the heat storage medium, ie, the evaporator is at least partially disposed within the said receptacle. As a result, the heat can be transferred from the heat storage medium to the refrigerant flowing through the evaporator by means of a heat flow. It is advantageous if a contact area between the evaporator and the heat storage medium is at least 50 cm ² , preferably at least 100 cm ² , more preferably at least 200 cm ² , so that as much heat as possible can be transferred per time.

According to an advantageous development of the heat exchanger has a flow channel for the air passing through the heat exchanger, wherein the flow channel is preferably formed by the above-mentioned walls of the heat transfer medium accommodating receptacle of the heat exchanger.

Preferably, at least one heat exchanger element, at which the air passing through the heat exchanger flows past when it is moved by means of the fan through the flow channel, extends into the flow channel. The surface of the heat exchanger element which comes into contact with the air (moist process air) can have a shape which deviates from a flat surface (in order to enlarge the surface in relation to a flat surface), so that the passing air or the air flowing from the Air entrained water vapor in a relatively short time can deliver a large amount of heat to the heat transfer medium. For example, the heat exchanger element comprises a plurality of fins which extend into the flow channel and preferably also into the heat transfer medium.

According to an advantageous development, the heat exchanger element (of which in principle several may also be present) has one or more heat exchanger elements. sections that extend into the heat storage medium (the heat exchanger sections may be formed for example by the above-mentioned fins). With the heat exchanger sections (s) a thermal bridge is formed between the sections of the heat exchanger element which come into contact with the air flowing through the heat exchanger and the heat storage medium. The heat of the passing water vapor thus flows via the heat exchanger element to the or the heat exchanger sections (s) and from there into the heat storage medium.

According to an advantageous development, the fan is arranged downstream of the heat exchanger in the flow direction of the air passing through the heat exchanger during operation of the fan. As a result, the process air coming from the receiving space, when it reaches the fan, has already removed a large part of the moisture through the heat exchanger, so that the moisture is largely prevented from precipitating on the fan and permanently damaging it.

According to an advantageous development, the heat pump arrangement comprises a condenser, with the aid of which the refrigerant compressed by the compressor is converted from the gaseous state into its liquid state, whereby heat is generated which can be removed from the condenser. Moreover, it is advantageous if the household dishwasher has an air inlet for the entry of air into the domestic dishwasher, in particular into the receiving space of the washing compartment. Finally, the household dishwasher can have means by means of which the heat released during the condensation of the refrigerant can be transferred from the condenser to the air flowing in via the air inlet into the household dishwasher, in particular into the receiving space of the washing compartment.

In the condenser, the refrigerant of the heat pump assembly is transferred from the gaseous state to the liquid state, wherein a condensation enthalpy is released. This causes the refrigerant to give off heat so that the air entering through the air inlet can be heated. The means for transferring this heat may, for example, be a further heat exchanger or a further heat exchanger element. The additional heat exchanger or the additional heat exchanger element may for example comprise a system of tubes and / or fins. In the further heat exchanger or heat exchanger element, the capacitor be arranged, or with the other heat exchanger or heat exchanger element, the capacitor may be thermally coupled in any other way, which heats the system of tubes and / or fins. Between the pipes and / or in particular through the fins, the incoming air can flow and thereby absorb the heat. When the air entering the domestic dishwasher from outside is heated, it can absorb more moisture so that the drying effect of the air on the wet items is improved.

Moreover, it is advantageous if the domestic dishwasher has a control and / or regulating unit which is designed to operate the domestic dishwasher according to a method of the preceding description. The control and / or regulating unit is connected to the heat pump assembly and / or the fan. In addition, the control and / or regulating unit operates all other necessary for the operation components of the household dishwasher.

It may be expedient, if appropriate, if the outlet location at which the process air dehumidified by the heat exchanger leaves the domestic dishwasher is removed from the inlet location where the outside air enters the domestic dishwasher so far that sufficient decoupling between supply air and exhaust air flow is ensured. This again improves the efficiency of the drying in the drying step of the respective wash program.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings. They show, in each case in a schematic outline sketch:

1 shows a household dishwasher with a receiving space, a

Heat exchanger and a heat pump assembly, and Figure 2 shows the heat exchanger and the heat pump assembly of Figure 1

Elements with the same function and mode of operation are each provided with the same reference numerals in FIGS. FIG. 1 shows a domestic dishwasher 1 with a receiving space 2 in its washing container 21, with a heat exchanger 4 and with a heat pump arrangement 6. In the receiving space 2, items 3 to be cleaned are arranged, which during a liquid-carrying partial program step or several liquid-carrying partial program steps of a dishwashing program a rinsing liquor or rinsing liquid (not shown) acted upon, in particular by means of one or more, arranged in the rinsing sprayer is sprayed.

Preferably, the respective dishwashing program to be carried out has the liquid-carrying partial program steps of pre-rinsing step, cleaning step, intermediate rinsing step, final rinse step and a drying step concluding a dishwashing program, one after the other. In this case, if necessary, the pre-rinsing step and / or the intermediate rinsing step can be dispensed with. Possibly. is also a dishwashing program possible, in which the respective liquid-carrying partial program step such. Intermediate rinse step is performed several times. Liquid-carrying partial program steps, in which the rinsing liquor is heated to a desired minimum temperature, are preferably the cleaning step and the final rinse step. In the rinse step of the respective dishwashing program, water is expediently mixed with a rinse aid in order to reduce the surface tension of the water and thereby improve its dripping behavior of the items to be washed. In particular, during the cleaning step of the respective dishwashing program, the rinsing liquor or rinsing liquid is heated to a certain minimum temperature. The rinsing liquor or rinsing liquid is advantageously heated to above 60 ° C. in the cleaning step, so that its cleaning effect is increased. It is formed in the purification step by a predetermined amount of water to which one or more cleaners are added.

With the rinsing liquor to be heated at the respective partial program step - as in the exemplary embodiment preferably during the cleaning step - the elevated temperature of the rinsing liquor is also accompanied by an increased air humidity of the air in the receiving space 2. The air in the receiving space 2 has substantially the same temperature as the heated rinsing liquor or rinsing liquid. In particular, in the last liquid-conducting partial program step of the dishwashing program - here in the exemplary embodiment in the final rinse step of the dishwashing program, water added as rinse liquor with rinse aid is in the receiving space 2 previously heated during the cleaning step on the then already warm or heated items being sprayed by means of one or more spray - kept high the moisture content of the air in the receiving space, in particular so high that a relative humidity of about 100% is present. This is even more the case when, during the rinsing step, the rinse aid liquor is also heated by means of the heat pump arrangement and / or by means of a separate heating device such as a liquid continuous flow heater and distributed in the receiving space with the wash ware, in particular by means of one or more spray devices. In order to dry the items to be washed 3 temporally after the last liquid-conducting part program step of the dishwashing program, here the final rinse step, fresh air or supply air is directed into the receiving space 2 from the outside during the drying step of the respective dishwasher program of the household dishwasher 1. The inflowing fresh air or outside air is symbolized in each of FIGS. 1, 2 by an arrow 22. The fresh air takes on the moisture that adheres to the items 3, and thus has a high water content and high humidity. The water content is in particular higher than the water content of the ambient air of the household dishwasher 1, which is placed for example in a kitchen. Would this warm air with the increased humidity now untreated escape from the domestic dishwasher 1 as exhaust air, the water contained in the exhaust air would condense on such surfaces of the environment of the domestic dishwasher 1, the material temperature is lower than the dew point of effluent from the domestic dishwasher exhaust air. The surfaces may be damaged by the moisture deposited thereon, especially if the surfaces have wood components. In addition, fungi and bacteria can multiply in the moisture, which are extremely undesirable, especially in kitchens. The fresh air, which receives the moisture from the items to be washed 3, for example, by an air inlet 12 and via an adjoining air inlet duct 13 into the receiving space 2 arrive. In the exemplary embodiment shown in FIG. 1, a heat exchanger 4, which extracts water from the process air emerging from the receiving space 2, is now arranged in the household dishwasher 1. For this purpose, the heat exchanger 4 preferably comprises at least one heat exchanger element 14, which, as explained in more detail below, has a temperature which ensures that the water vapor contained in the air at least partially condenses on the heat exchanger element 14.

In any case, the temperature of the heat exchanger element 14 (of which a plurality may also be present) should be lower than the temperature, in particular dew point, of the air-steam mixture fed from the receiving space 2 to the heat exchanger 4 in order to achieve the desired condensation of the water vapor enable. In particular, the temperature of the heat exchanger element 14 is lower than the temperature of the household dishwasher 1 directly surrounding surfaces, for. As the adjacent to the household dishwasher 1 surfaces of the household dishwasher 1 surrounding kitchen cabinet. This ensures in particular that the amount of water in the air leaving the household dishwasher 1 is reduced in such a way that little or no water condenses on the surfaces mentioned. The condensed water in the heat exchanger 4 can be returned to the wash liquor and / or cached for a liquid-conducting part program step of a subsequent dishwashing program, so that the water consumption of the household dishwasher 1 is reduced. The heat exchanger element 14 may, for example, have fins or be formed by lamellae, so that the surface of the heat exchanger element 14 coming into contact with the process air or the water vapor entrained by the process air is increased. As a result, a particular amount of water vapor can condense on the heat exchanger element 14 per time interval.

In order to keep the temperature of the heat exchanger element 14 low, in particular lower than the temperature of the moist warm process air exiting from the receiving space 2 and entering the heat exchanger 4, the domestic dishwasher 1 has a heat storage medium 5. The heat storage medium 5 can bei- For example, be a coolant, in particular water, or include, which has a high specific heat capacity and / or a high enthalpy of fusion.

The heat exchanger element 14 may have one or more heat exchanger sections 15, which protrude into the heat storage medium 5, so that heat can be transferred from the heat exchanger element 14 to the heat storage medium 5 particularly well. As a result, the heat exchanger element 14 can be kept at an approximately constant low temperature (the temperature should be at least lower than the temperature of the moist-warm process air emerging from the receiving space 2). The process air flowing out of the household dishwasher and dried after flowing through the heat exchanger 4 is symbolized by an arrow 23 in FIGS. 1, 2.

Furthermore, the domestic dishwasher 1 has an air channel 8 through which the process air exiting from the receiving space 2 is conveyed to the heat exchanger element 14. Adjoining the air channel 8 is a flow channel 10 which leads the process air for dehumidification through the heat exchanger 4 and past the heat exchanger element 14. In the air duct 8 and / or in the flow channel 10, a fan 9 is arranged, which conveys the process air from the receiving space 2 to the heat exchanger 4 and therethrough. In the present embodiment, the fan 9 is arranged downstream of the heat exchanger 4 in the flow direction of the outflowing process air. This leads to the fact that the fan 9 already reaches dried air, so that little or no moisture condenses on the fan 9. As a result, the fan 9 is protected from damage.

In addition, the domestic dishwasher 1, a heat pump assembly 6, which removes heat from the heat storage medium 5 to cool it and thus to allow condensation of transported through the heat exchanger 4, carried by the air, water vapor. For this purpose, the heat pump assembly 6 an evaporator 7, which is adapted to receive heat from the heat storage medium 5 in order to cool it. FIG. 2 shows a detail of FIG. 1, which shows the heat exchanger 4 and the heat pump arrangement 6. Through the flow channel 10, the hot-humid process air flowing out of the receiving space 2 is conducted to the heat exchanger 4. In the heat exchanger 4, at least one heat exchanger element 14 is arranged, which is cooled by the heat transfer medium 5. The water vapor contained in the moist-warm process air condenses on the heat exchanger element 14, so that the process air is dried or water is withdrawn. By condensing the water vapor of the process air, this heat transfers to the heat exchanger element 14. The dried process air leaves the household dishwasher 1 finally through the air outlet 1 1 as exhaust air (see Figure 1).

The heat exchanger element 14 preferably comprises heat exchanger sections 15 which extend into the heat storage medium 5. Through the heat exchanger sections 15, heat which is discharged from the passing air-water vapor mixture to the heat exchanger element 14 is transferred from the heat exchanger element 14 to the heat storage medium 5. The heat storage medium 5 can be, for example, water or a water-salt solution or comprise water or a water-salt solution. The heat storage medium 5 may be liquid during the process, or it may first be solid and melted by the heat absorption of the heat exchanger element 14. As a result, the heat storage medium 5 can absorb more heat than if it retains its state of aggregation despite heat absorption. In the heat storage medium 5 preferably at least partially extends the evaporator 7, which is part of the heat pump assembly 6. In the evaporator 7, a refrigerant is arranged, which can pass through the heat of the heat storage medium 5 in the gaseous state and thereby absorbs the heat. The refrigerant may then be passed to a compressor 17, which increases the pressure of the gaseous refrigerant, wherein the temperature of the refrigerant increases. In a condenser 18 of the heat pump assembly 6, the heated refrigerant condenses and releases the heat to an environment of the condenser 18. As shown in the present embodiment, the capacitor 18 is, for example, in the air inlet channel 13 is arranged. Through this fresh air can flow from the environment into the receiving space 2 of the washing container 21 of the household dishwasher 1 as a supply air. In this case, it is conducted past the condenser 18 of the heat pump arrangement 6, so that the fresh air is heated. As a result, the water absorption capacity of the reaching into the receiving space fresh air, so that there the drying effect of the fresh air is increased to the items to be dried 3 to be dried.

Additionally or alternatively, in the air inlet duct 13, a heating element (not shown) may be arranged, which preheats the incoming fresh air. The heating element may comprise, for example, an electric heating coil.

Additionally or alternatively, the heat released by the condenser 18 of the heat pump arrangement 6 can also be transferred to the rinsing liquor. In this case, the rinsing liquor to be heated is guided past or past the capacitor 18 by an additional channel (not shown here). Thereby, the power consumption of the household dishwasher 1 can be reduced.

The refrigerant is passed to the condenser 18 to a throttle 16. The throttle 16 reduces the pressure of the refrigerant, whereby it cools. Thereafter, it returns to the evaporator 7, so that it can again absorb heat from the heat storage medium 5, in the process itself merges into the gaseous state and the cycle of the heat pump arrangement 6 is thus closed.

In a modification of the above embodiment of Figures 1, 2, the heat exchanger 4 in a dual function as a heat storage tank for removal of heat energy from the stored therein heat storage medium 5, in particular water, through the heat pump assembly 6 and at the same time as a removal tank or filling tank for supplying treatment liquid be formed in the receiving space 2 of the washing container of the household dishwasher. The heat storage medium 5, in particular storage water, from this heat exchanger 4 is thus at least partially used as a treatment liquid in the receiving space in the respective liquid-conducting partial program step of a washing program. Due to its dual function as a heat exchanger and filling tank, space in the dishwasher is advantageously saved, ie it is not necessary to have space for a separate tank with heat exchanger. Storage medium and space for a separate tank with treatment liquid or process fluid, especially fresh water to provide within the dishwasher. In this embodiment, it is expedient if the heat exchanger is formed by a container in the inlet side water, especially fresh water, as a heat storage medium and treatment liquid, via a supply, in particular from a water supply network, can be filled, and from the outlet side via a discharge water as Treatment liquid or process fluid in the receiving space of the washing container of the dishwasher can be fed. In the figure 1, such a feed line is shown in phantom and designated 19. In the figure 1, such a discharge line is shown in phantom and designated 20. The heat exchanger is therefore preferably operated here as an open tank with a water inlet and a water outlet. If per wash program, the heat storage medium in the tank or container of the heat exchanger is at least partially or completely changed, ie the container stored there heat storage medium partially or completely removed and filled with fresh heat storage medium, especially fresh water, so the risk of unwanted contamination the container of the heat exchanger largely avoided. Also, this change of the heat storage medium can be beneficial for the thawing of any ice that has formed in the storage tank from the heat storage medium during the respective active phase of operation of the heat pump assembly where heat is removed from the heat storage medium. Because the temperature and thus the thermal energy content of the heat storage medium newly supplied to the storage tank, for example fresh water, is usually higher than the temperature and the thermal energy content of the heat storage medium frozen into ice in the storage tank.

In addition, in a drying system of the domestic dishwasher, during which process of the respective washing program process air from the receiving space, in particular via a connected to an air outlet of the receiving space air duct preferably by means of a blower, transported out and delivered to the environment of the dishwasher as exhaust air, after In an advantageous development, a section of this air channel on an outer wall of the container or storage container filled with the heat storage medium, preferably thermal contact mixed, lead past, or pass through the container. In particular, it may be favorable if a partial area or the total area of a wall of the storage container forms or replaces a wall section of the air channel, so that the process air exiting from the receiving space directly, ie directly contacting, on a wall of the storage tank or storage container filled with the heat storage medium can pass by.

Expressed in general terms, by virtue of the fact that the air duct is thermally coupled to the storage tank at least along a section of its course, effective heat transfer can be effected in a simple manner between the heat storage medium of the storage tank and the process air led out of the receiving space. The process air and the heat storage medium remain materially separated from each other. It may be expedient, if appropriate, if the heat exchanger is attached on the outside to a wall, in particular side wall, of the washing container of the domestic dishwasher, and in particular a thermal insulation layer or thermal barrier is provided between the heat exchanger and the wall of the washing compartment. As a result, a heat transfer short circuit between the storage container of the heat exchanger and the receiving space of the washing container can be largely avoided. At the same time, the storage container still serves as a thermal energy sink for heat loss, which escapes despite the thermal insulation layer from the washing. For the sake of clarity of drawing, such a thermal insulation layer is not shown in FIGS. 1, 2.

Generally speaking, the exhaust air which flows out of the receiving space of the washing container out into the environment at the installation location of the dishwasher during the drying phase of the washing cycle of the respective dishwashing program, is thus included before it leaves the dishwasher, ie before being dispensed to the surrounding area brought into thermal contact with the storage container and / or with the thermally coupled evaporator of the heat pump assembly and cooled that their temperature is lower than the temperature of the objects such as the adjacent kitchen furniture or the countertop in the vicinity of the dishwasher. In particular, the dew point temperature of the exhaust air is lowered to such an extent that is less than the temperature of the adjacent objects or materials in the vicinity of the dishwasher and / or less than the temperature of the ambient air. The moisture contained in the exhaust air flowing out of the receiving space is preferably condensed out on a cool surface of the storage tank and / or evaporator filled with the heat storage medium, which has been made cold by the preceding heat pump operation, before the exhaust air leaves the dishwasher. that little or no residual moisture, which is still contained in the thus dried exhaust air, can condense on objects in the vicinity of the dishwasher.

The present invention is based in particular on the following: in open drying systems moist air is released to the environment. At the exit point, condensation may occur and cause damage to the surrounding components. By this invention, the formation of condensation should be avoided.

In known solutions z. For example, the moist air is blended with fresh air before the air is released into the environment. Other solutions preheat the worktop with a warm airflow to prevent condensation. In the context of the present invention, in particular a heat exchanger can preferably be integrated in a container filled with cold fluid. The container may expediently have an inlet air opening and an exhaust opening. The heat exchanger may preferably be positioned therebetween. The heat exchanger may in particular be designed so that ribs or the like. make it possible to remove the heat from the cold fluid. The fluid may preferably be removed by an evaporator of a heat pump, the heat during the drying process or in the previous heating phases.

One possible embodiment is characterized in particular as follows: During the drying phase, a fan is put into operation in order to extract the moist process air from the dishwasher. The fan is preferably positioned after the heat exchanger. The process air is suitably cooled by the heat exchanger so that moisture condenses out and the air is brought to a higher relative humidity and a lower dew point. If the air is released to the environment ben, it has 100% relative humidity, but at a lower temperature level. The additional mixing effect with the ambient air avoids further condensation on surrounding components. The required cold can be provided by commissioning a heat pump.

The resulting negative pressure in the dishwasher flows expediently at a Zuluftöffnung fresh air. This fresh air can in turn preferably be preheated by a heat exchanger, which transfers the heat in particular from the condenser of the heat pump, in order to reduce the dew point and to dry the items to be washed efficiently.

Another possible embodiment is analogous to the embodiment described above with the difference that the heat pump is not active during the drying process. The fluid in the container was cooled down in the preceding washing phases to keep the dew point of the exhaust air lower than the dew point of the environment.

Another possible embodiment is analogous to the embodiment described above with the difference that instead of the coupled with the condenser of the heat pump assembly heat exchanger for the preheating of the incoming fresh air, a heating element is used.

The invention leads in particular to the following advantages: no condensation problem on furniture or the environment,

Use of energy-saving heat pump in the drying process possible, by sucking in fresh air is achieved an energy advantage compared to closed systems. Incidentally, the invention is not limited to the illustrated embodiment. Rather, all combinations of the individual features described, as shown or described in the claims, the description and the figures and as far as a corresponding combination is technically possible or seems reasonable, the subject of the invention. LIST OF REFERENCE NUMBERS

1. Household dishwasher

2nd recording room

3. Washware

4. heat exchanger

5. heat storage medium

6. Heat pump arrangement

7. evaporator

8. Air duct

9. Fan

10. Flow channel

1 1. air outlet

12. Air intake

13. Air intake duct

14. heat exchanger element

15. Heat exchanger sections

16. Throttle

17th compressor

18. Capacitor

19. Feed line

20. discharge line

21. rinse tank

22. inflowing outside air

23. outflowing process air

Claims

Method for operating a domestic dishwasher (1) as part of a wash program, wherein the wash program comprises a partial program step, in particular cleaning step, while in a receiving space (2) of the domestic dishwasher (1) arranged wash ware (3) is supplied with heated wash liquor, and wherein the rinsing program comprises at least one drying step which is subordinate to the partial program step, in particular cleaning step, during which air flows into the receiving space (2), absorbs moisture therefrom from the items to be washed (3), and finally leaves the domestic dishwasher (1), wherein the domestic dishwasher (1) comprises a heat exchanger (4) with a heat storage medium (5) and a heat pump assembly (6), wherein the heat storage medium (5) by means of the heat pump assembly (6) before and / or during the drying step heat is removed, Air during d it is passed through the heat exchanger (4) before it is discharged to the environment of the domestic dishwasher (1), and heat is removed from the air entrained by the air in the region of the heat exchanger (4), which in turn on the heat storage medium (5 ) is transferred, so that the water vapor in the region of the heat exchanger (4) at least partially condensed.

Method according to the preceding claim, characterized in that a water content of the air with the aid of the heat exchanger (4) is reduced to a maximum of 50 g water / m ³ air, preferably to a maximum of 15 g water / m ³ air.

Method according to one of the preceding claims, characterized in that the temperature of the heat storage medium (5) by means of an evaporator (7) of the heat pump assembly (6) is reduced during the cleaning step.

Method according to one of the preceding claims, characterized in that in the household dishwasher (1) during the drying step incoming air is heated prior to contact with the items to be washed (3).

A method according to the preceding claim, characterized in that the incoming air is heated by the heat is supplied to the air, which is released during operation of the heat pump assembly (6) in the region of a condenser (18) of the heat pump assembly (6).

Method according to one of the preceding claims, characterized in that the air with the aid of a fan (9) through the heat exchanger (4) is passed, that the heat pump assembly (6) comprises a compressor (17), and that the rotational speed of the fan (9 ) and / or the power of the compressor (17) is adjusted taking into account the humidity and / or the dew point temperature of the air leaving the heat exchanger (4).

Household dishwasher for cleaning items to be washed (3) having a receiving space (2) for receiving the items to be cleaned (3), the domestic dishwasher (1) having a heat exchanger (4) with a heat storage medium (5), wherein the domestic dishwasher (1) a Heat pump assembly (6), by means of which heat from the heat storage medium (5) on a during the operation of the domestic dishwasher (1) in the domestic dishwasher (1) existing, in particular circulating, rinsing liquor is transferable, wherein the heat pump assembly (6) has an evaporator (7 ), which is arranged such that heat from the heat storage medium (5) on the evaporator (7) is transferable, wherein the domestic dishwasher (1) the receiving space (2) and the heat exchanger (4) connecting air duct (8) and a fan (9), with the aid of which air from the receiving space (2) via the air channel (8) in the heat exchanger (4) is movable, and wherein the domestic dishwasher (1) has a heat exchanger (4) downstream Luftaus- lass (1 1), which is so in communication with the environment of the domestic dishwasher (1), that in the heat exchanger (4) inflowing air after passing through the heat exchanger (4) via the air outlet (1 1) from the domestic dishwasher (1) can escape.

Domestic dishwashing machine according to the preceding claim, characterized in that the evaporator (7) of the heat pump assembly (6) is at least partially surrounded by the heat storage medium (5).

Domestic dishwashing machine according to claim 7 or 8, characterized in that the heat exchanger (4) has a flow channel (10) for the heat exchanger (4) passing air, wherein in the flow channel (10) at least one heat exchanger element (14) extends to the the air passing through the heat exchanger (4) during operation of the fan (9) passes.

10. Domestic dishwasher according to one of claims 7 to 9, characterized in that the heat exchanger element (14) of the heat exchanger (4) has one or more heat exchanger sections (15) which extend into the heat storage medium (5).

1 1. Domestic dishwasher according to one of claims 7 to 10, characterized in that the fan (9) is arranged downstream of the heat exchanger (4) in the flow direction of the heat exchanger (4) during operation of the fan (9) leaving the air.

12. Domestic dishwasher according to one of claims 7 to 1 1, characterized in that the heat pump assembly (6) comprises a condenser (18) that the domestic dishwasher (1) an air inlet (12) for the entry of air into the domestic dishwasher (1) and that the household dishwasher (1) comprises means by which heat from the

Condenser (18) on the on the air inlet (12) in the household dishwasher (1) incoming air is transferable.

13. Domestic dishwasher according to one of claims 7 to 12, characterized in that the domestic dishwasher (1) a control and / or

Control unit which is adapted to operate the domestic dishwasher (1) according to a method according to one of claims 1 to 6.

14. Domestic dishwasher according to one of claims 7 to 13, characterized

in that a storage tank for the heat storage medium (5), in particular water, is provided as the heat exchanger (4).

15. Domestic dishwasher according to one of claims 7 to 14, characterized in that the heat exchanger (4) in a double function as a storage tank for the heat storage medium and as a removal container for supplying treatment liquid in the receiving space (2) is formed.

16. Domestic dishwashing machine according to claim 15, characterized in that the heat exchanger (4) is formed by a container in the inlet side water, especially fresh water, as a heat storage medium and treatment liquid, via a supply line (19), in particular from a water supply network, can be filled is, and from the outlet side via a discharge line (20) water as the treatment liquid in the receiving space (2) can be fed.

17. Domestic dishwasher according to one of claims 14 to 16,

characterized in that the heat exchanger (4) is attached to a wall, in particular side wall, of the washing container (21) of the household dishwasher, and in that a thermal insulation layer is provided between the heat exchanger (4) and the wall of the washing container (21) ,