WO2018077635A1

WO2018077635A1 - Dishwasher having a heat pump

Info

Publication number: WO2018077635A1
Application number: PCT/EP2017/076216
Authority: WO
Inventors: Andreas BABUCKE; Niels Liengaard
Original assignee: BSH Hausgeräte GmbH
Priority date: 2016-10-26
Filing date: 2017-10-13
Publication date: 2018-05-03
Also published as: DE102016221051A1

Abstract

The invention relates to a method for operating a domestic dishwasher (1) within the context of a dishwashing program, wherein the dishwashing program comprises a cleaning step, during which heated dishwashing liquid (4) is applied to objects to be washed (3) that are arranged in a holding chamber (2) of a domestic dishwasher, and wherein the dishwashing program comprises at least one drying step, arranged chronologically after the cleaning step and during which air flows into the holding chamber (2), picks up water there from the objects (3 to be washed and finally leaves the holding chamber (2) again. According to the invention, the domestic dishwasher (1) comprises a heat pump arrangement having an evaporator (5) for evaporating a refrigerant and having a condenser (6) for condensing the refrigerant, wherein the heat pump arrangement is operated at least from time to time before and/or during the drying step, wherein, during the drying step, heat is transferred from the air flowing in the direction of the holding chamber (2) to the evaporator (5) and/or to a heat reservoir (11) assigned to the evaporator (5), and wherein the domestic dishwasher (1) comprises an air heat exchanger (9), with the aid of which, during the drying step, at least from time to time heat is transferred from the air leaving the holding chamber (2) to the air flowing into the holding chamber (2). The invention further relates to a domestic dishwasher (1) having a heat pump arrangement and an air heat exchanger (9).

Description

Dishwasher with heat pump

The invention relates to a method for operating a domestic dishwasher as part of a wash program, wherein the wash program comprises a cleaning step during which in a receiving space of the domestic dishwasher arranged items to be washed with heated rinse (= water or water with cleaning and / or rinse aid) is applied, and wherein the rinsing program comprises at least one drying step subsequent to the cleaning step during which air flows into the receiving space, receives water there from the items to be washed and finally leaves the receiving space again.

Furthermore, the invention relates to a domestic dishwasher with a receiving space for receiving items to be washed, wherein the domestic dishwasher comprises a heat pump assembly with an evaporator for evaporating a refrigerant and with a condenser for condensing the refrigerant, the domestic dishwasher having a supply air duct, via the air during a Drying step of a wash program can flow into the receiving space, and wherein the household dishwasher has an exhaust duct, can flow through the air during the drying step from the receiving space.

Generic household dishwashers are known in the art and serve in principle the cleaning 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 case air absorbs the water which adheres to the items to be cleaned, whereby the item to be washed is dried. The now humid air leaves the household dishwasher and enters their environment, for example in a kitchen or is passed on a cooled wall of the domestic dishwasher to condense existing water vapor in the air.

The object of the present invention is to improve the known solution. The object is achieved by a method and a domestic dishwasher according to the independent claims.

The method according to the invention relates to the operation of a household dishwashing machine which, as usual, has a receiving space which can be closed by a door. During the operation of the domestic dishwasher, a washing program is run through which comprises at least the above-mentioned cleaning step and the above-mentioned and chronologically subsequent drying step. Furthermore, the domestic dishwasher has a heat pump arrangement. The heat pump assembly includes an evaporator for evaporating a refrigerant and a compressor for compressing the evaporated refrigerant. With the aid of the compressor, the entering into the compressor during operation of the heat pump assembly gaseous refrigerant is compressed, wherein it heats up. Furthermore, the heat pump assembly comprises a condenser, in which the heated gaseous refrigerant condenses again and thereby releases heat, which can be used for example by means of a heat exchanger for the heating of existing in the domestic dishwasher rinse. Subsequently, the liquefied refrigerant with the help of an expansion device (usually a throttle valve) is relaxed and finally passes back to the evaporator, in which it goes under heat absorption again in the gaseous state, and then fed again to the compressor

According to the invention, it is now provided that the heat pump arrangement, ie in particular the compressor, is operated at least temporarily before and / or during the drying step. This cools the evaporator. This is finally used to cool the air, which is intended for drying the dishes. For example, it is conceivable for heat (= heat energy) to be transferred to the evaporator from the air flowing in the direction of the receiving space before it enters the receiving space. The air cools down here. This in turn means that their relative humidity increases, condensing at a certain point in the air entrained water vapor. The air is thus dried by cooling with the aid of the evaporator. It should be noted that in the context of the invention the term "air" is understood to mean a gas mixture which has a certain air humidity, ie a certain water vapor content The term "air" therefore does not imply that the humidity has a constant or defined amount.

In any case, the air after the removal of heat, which was transmitted to the evaporator example, has a lower absolute humidity than before the heat removal. Thus, this air can absorb more water from the dishes than if the heat extraction would be omitted. The drying of the dishes is thus accelerated.

Incidentally, the heat transfer from the air subsequently flowing into the receiving space of the domestic dishwasher can be effected by virtue of the evaporator having an evaporator surface (eg fins or lines through which the coolant flows) through which the air is guided before entering the receiving space becomes. Likewise, it would be conceivable that the evaporator is in operative connection with a heat exchanger having a heat exchanger medium, so that the heat of the air is not transmitted directly to the evaporator, but indirectly via the heat exchanger to the evaporator.

It is also conceivable that the evaporator is associated with a heat storage on the heat from the air is transferable before it enters the receiving space. The heat accumulator can be in operative connection with the evaporator, for example, via a heat exchanger. In any case, it is advantageous if the heat pump assembly is operated before or before and during the drying step in this case. This ensures that the heat storage is already cooled before the drying step (preferably to a temperature just above 0 ° C). Finally, if the air flows in the direction of the receiving space during the drying step, it is cooled down in the region of the heat accumulator so that the desired condensation of water vapor entrained in the air occurs. The heat accumulator may comprise a container in which z. As water or another latent heat storage material is located. Furthermore, the invention provides that the household dishwasher comprises an air heat exchanger, with the aid of which heat is at least temporarily transferred from the air leaving the receiving space to the air flowing into the receiving space during the drying step. During the drying step, air that is as dry as possible (which has previously been dried by heat removal as described above) flows into the receiving space. After passing through the ware (in which water is transferred from the ware to the air), the air exits the receiving space again.

It is conceivable in this context that the emerging from the receiving space air exits after exiting the receiving space from the household dishwasher and thus in their environment. Alternatively, the air emerging from the receiving space can also be fed again to the receiving space, wherein this air would have to be withdrawn again for the purpose of drying heat. This could be done, for example, by the evaporator as described above and / or, as described below, with the aid of an air heat exchanger.

In any case, it is provided that the air flowing out of the receiving space passes through the mentioned air heat exchanger. The air heat exchanger comprises at least two sections, the air flowing into the receiving space flowing through the one section and the air flowing out of the receiving space through the other section through the one section. Both sections can only be separated from each other by a wall which simultaneously forms a spatial boundary of both sections. However, it is also conceivable that a heat-conducting element or a heat exchanger is arranged between said sections.

According to the invention, the air heat exchanger is designed to effect a heat transfer from the air exiting the receiving space to the air flowing into the receiving space subsequently (ie after the heat transfer). In other words, the air leaving the receiving space is thus cooled with the aid of the air heat exchanger, while the air flowing into the receiving space is heated by means of the air heat exchanger. This has two advantages. On the one hand, the relative humidity of the incoming air into the receiving space before entry into the receiving space is reduced (the absolute humidity remains constant), so that the air within the receiving space can absorb more water from the dishes until the relative Humidity has risen to 100%. The water absorption capacity is thus increased compared to a solution without air heat exchanger. On the other hand, the absolute humidity of the air leaving the receiving space (the relative humidity is about 100% after leaving the receiving space) is reduced by their cooling and the associated condensation of a portion of the water vapor entrained by the air. The air is dried.

The dried air can then leave the household dishwasher, d. H. escape in their environment without the risk of moisture-related damage to the objects surrounding the household dishwasher (eg kitchen furniture). If the air is circulated during the drying step, the air heat exchanger has the advantage that the air has already been dried before re-entry into the receiving space.

According to an advantageous development, during the drying step, at least temporarily so much heat is transferred from the air leaving the receiving space to the air flowing into the receiving space that water vapor contained in the air leaving the receiving space at least partially condenses outside the receiving space. During the cooling of the air leaving the receiving space, although their relative humidity remains the same or increases only slightly to 100%. On the other hand, the absolute humidity is reduced by the condensation of water vapor. Preferably, the domestic dishwasher comprises a condensate removal for receiving and removing the resulting condensate. This is added during the drying step, for example, the rinsing liquor or discharged through a drain from the domestic dishwasher.

According to an advantageous development, the air leaving the receiving space and the air flowing into the receiving space flow in countercurrent through the air heat exchanger. Preferably, the air heat exchanger comprises the above-mentioned two sections, whereby a section can be part of a supply air duct and the second section can be part of an exhaust air duct of the household dishwasher. In particular, the air heat exchanger should comprise a common partition for both sections, wherein on one side of the partition wall, the air exiting from the receiving space flows past the partition in a first direction, while after passing through the air Heat exchanger in the receiving space inflowing air flows past on a second side of the partition in the opposite direction to the partition wall. Of course, the sections may be rectilinear or curved, meander-shaped or labyrinth-shaped in order to increase the heat transfer between the respective air masses.

According to an advantageous development, during the drying step, at least temporarily so much heat is transferred from the air flowing into the receiving space to the evaporator that water vapor contained in the air condenses outside the receiving space. Preferably, during the drying step, air from the environment of the household dishwasher flows through an air inlet into a supply air duct of the domestic dishwasher. In any case, the air coming into direct or indirect contact with the evaporator, which usually has a relative humidity of less than 100%, should be cooled by the evaporator until the relative humidity first rises to 100% and then to water vapor condensed from the air. The absolute humidity of the air is thus reduced with the help of the evaporator, while the relative humidity is increased. Also in this case, it is advantageous if the resulting condensate is collected by means of a condensate discharge and forwarded to the wash liquor or a drain.

Incidentally, the evaporator should at least partially protrude into the supply air duct of the domestic dishwasher or be arranged in this, in order to be able to be directly passed by the air flowing into the domestic dishwasher. The cooled and dried with the aid of the evaporator air finally flows to the air heat exchanger and is reheated there, so that their relative humidity is significantly reduced again. The air thus treated is thus particularly well suited for absorbing water vapor in the receiving space and thus for drying the dishes. Preferably, the air in the air heat exchanger is increased to such an extent that the relative humidity of the air leaving the air heat exchanger and subsequently entering the receiving space is less than 20%, preferably 10%.

According to an advantageous development, the air emerging from the air heat exchanger is discharged from the domestic dishwasher, without previously again in the To reach the recording room. In other words, it is therefore advantageous if during the drying step air from the environment of the domestic dishwasher enters via an air inlet into a supply air duct of the domestic dishwasher, cooled by the evaporator and dried, passes through the air heat exchanger and is heated there, passes through the receiving space and there receives water from the dishes, exits the receiving space, cooled by the air heat exchanger and dried and finally exits through an air outlet from the domestic dishwasher in their environment. Alternatively, it would also be possible for the air leaving the receiving space to return to the effective range of the evaporator after passing through the air heat exchanger, so that the air would be recirculated as a result.

According to an advantageous development, the heat pump arrangement is operated at least temporarily during the cleaning step, in which case heat is transferred from the condenser to water flowing into the domestic dishwasher or water already present there or rinsing liquor already existing there. The resulting during operation of the heat pump assembly heat is thus used to heat water before entering the receiving space. In this case, the heat pump assembly, i. H. in particular, their compressors are operated during or shortly before a rinsing program step in which heated water is needed (for example during a cleaning or rinsing step).

Additionally or alternatively, it is also possible to transfer the heat generated during operation of the heat pump assembly from the condenser to a heat accumulator associated with the condenser. The heat store can be, for example, a container filled with a liquid (eg water) or a special latent heat storage material (such as paraffin). If the heat pump arrangement is now operated, for example, during a rinsing program step during which no heated water is needed in the receiving space, the heat can be transferred from the condenser to the said heat store. This would be conceivable, for example, during the drying step. If warm water is finally needed again in a subsequent rinse program, the heat stored in the heat store can finally be transferred again from the heat store to the water present in the household dishwasher or the water flowing into the domestic dishwasher, with one here the condenser in operative connection standing heat exchanger can be used.

According to an advantageous development, the heat pump arrangement is operated at least temporarily during the cleaning step, in which case heat is transferred from a heat accumulator associated with the evaporator to the evaporator. The heat accumulator may also comprise a container of water or other latent heat storage material. The heat accumulator absorbs heat from the environment of the domestic dishwasher outside the drying step. Finally, during a cleaning step or other rinsing program step, during which no air flows into the receiving space via the supply air duct (eg during a final rinse step), this heat may be released to the operation of the heat pump arrangement. Embodiments and further developments of the method according to the invention are explained in the description of the claimed domestic dishwasher.

The household dishwasher according to the invention comprises the heat pump arrangement described hitherto or hereinafter with a condenser, an evaporator, an expansion element and a compressor. Furthermore, there is a supply air duct through which air, preferably from the environment of the domestic dishwasher, can flow into the receiving space during a drying step. Likewise, an exhaust duct is provided, can flow through the air from the receiving space, the exhaust duct preferably opens into an air outlet, can escape through the air from the domestic dishwasher in their environment.

The household dishwasher is characterized according to a first embodiment, characterized in that with the aid of the heat pump assembly heat from the over the supply air duct into the receiving space flowing air to the evaporator is transferable. Preferably, at least a part of the evaporator protrudes into the supply air duct. Likewise, the entire evaporator can be arranged within the supply air duct. Alternatively, a thermally conductive component is present within the supply air duct, which is in heat-conducting contact with the evaporator. Alternatively or additionally, it is also possible for the household dishwasher to have a heat accumulator associated with the evaporator, with heat being transferable from the air flowing into the receiving space to the heat accumulator associated with the evaporator. Thus, the heat then flowing into the receiving space during the drying step, heat can be withdrawn even if the heat pump assembly is not or only temporarily operated during the drying step. However, a prerequisite for this is that the heat pump arrangement is operated at least before the drying step, for example during a cleaning step preceding the drying step. Since the heat store is in operative connection with the evaporator, the heat store or the heat storage material present in the heat store (eg water or an aqueous solution or another latent storage material) is always cooled when the heat pump arrangement is operated. It is further provided that the domestic dishwasher comprises the already described air heat exchanger, with the aid of which heat from the receiving space via the exhaust air leaving the air is transferred to the over the supply air duct into the receiving space flowing air. The air heat exchanger preferably comprises two separate air channels, which may be straight or curved and may also have a plurality of branches to increase the flow path within the air heat exchanger. While an air duct communicates with or is part of the supply air duct of the domestic dishwasher, the second air duct communicates with or is part of the exhaust air duct. According to an advantageous development, the domestic dishwasher has at least one condensate removal, with the aid of condensate can be discharged, which is formed in the region of the air heat exchanger and / or in the region of the evaporator. The respective condensate discharges can be connected, for example, via a common condensate line, which in turn opens into a pump sump of the household dishwasher or a drain through which the household dishwasher is connected to a sewer line.

According to an advantageous development of the air heat exchanger comprises a portion of the supply air duct and a portion of the exhaust duct, said sections directly or with the interposition of a heat conducting element with each other in thermally conductive contact. The air heat exchanger can thus be formed in principle by a portion of the supply air duct and a portion of the exhaust duct, both being separated in a certain area by a common partition wall. In addition, this area can be insulated by insulation to prevent heat loss.

According to an advantageous development, the household dishwasher comprises a fan, by means of which air through the supply air duct and / or the exhaust duct is movable. Preferably, the fan (= fan or blower) is integrated in the supply air duct or the exhaust duct. In particular, it is advantageous to arrange the fan in the supply air duct between the point at which the air flowing in the direction of the receiving space is cooled by the evaporator and the inlet opening of the receiving space provided for the air, since here the air is relatively dry.

According to an advantageous development, the domestic dishwasher has an air inlet, via which during the drying step air from the environment of the domestic dishwasher can enter the household dishwasher. This may be an opening in the region of an outer wall of the household dishwasher. Furthermore, the domestic dishwasher preferably has an air outlet, via which air can escape from the household dishwasher during the drying step. The air outlet may also be an opening in the region of an outer wall of the household dishwasher.

According to an advantageous development of the air inlet via a supply air duct with the receiving space and the receiving space via the exhaust duct to the air outlet. In this case, the air can flow into the household dishwasher via the air inlet from the environment of the household dishwasher, enter the receiving space via the supply air duct, wherein a section of the supply air duct can be part of the air heat exchanger. After passing through the receiving space in which the air absorbs water from the items to be washed, the air can escape from the receiving space again, pass through the air heat exchanger and finally exit via the air outlet from the household dishwasher. According to an advantageous development, the domestic dishwasher has a condenser associated heat storage in operative connection with the condenser, that during operation of the heat pump assembly heat from the condenser to the condenser associated heat storage is transferable. This is useful when the heat pump assembly is operated at a time, for example, during the drying step, when no water inside the household dishwasher or water flowing into the domestic dishwasher needs to be heated. The heat released by the condenser can be temporarily stored with the aid of the heat accumulator mentioned. Preferably, this heat storage is connected via a heat exchanger with a water cycle of the domestic dishwasher in connection, so that heat from said heat storage on the circulating in the domestic dishwasher water is transferable. The heat exchanger can be, for example, a wall of the heat storage device, past which water is passed.

Additionally or alternatively, the domestic dishwasher can also have a heat accumulator associated with the evaporator, which is operatively connected to the evaporator in such a way that heat can be transferred from the heat accumulator associated with the evaporator to the evaporator during operation of the heat pump arrangement. This is advantageous when the heat pump assembly is operated without air flowing through the supply air duct into the receiving space, for example during a cleaning step, during which water present in the domestic dishwasher or water entering the domestic dishwasher with the aid of the condenser during operation of the heat pump assembly heat is to be heated.

According to an advantageous development, the domestic dishwasher has a control and / or regulating unit, which is designed to operate the domestic dishwasher according to the previous or following description. Some of the described process features can be implemented individually or in any combination, provided that this does not result in a technical contradiction or a contradiction to the independent claims. The above-explained and / or reproduced in the subclaims advantageous embodiments and refinements of the invention can - in addition to z. B. in cases of clear dependencies or incompatible alternatives - individually or in any combination with each other.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings. 1 shows an exemplary embodiment of a domestic dishwasher according to the invention, a possible temperature change of the air flowing through the domestic dishwasher, and a possible change in the absolute and relative humidity of the air flowing through the domestic dishwasher.

In the following figures, only those components of a Haushaltsischtirrspül- machine 1 are provided with reference numerals and explained, which are required for the understanding of the invention. It goes without saying that the household dishwasher 1 according to the invention can comprise further parts and assemblies. Furthermore, FIG. 1 shows a series of sections outside the walls 23 of the household dishwasher 1. Of course, these or at least a part of them are in reality within said walls 23. The selected representation is therefore only for clarity.

The domestic dishwasher according to the invention 1 comprises, as I said, a plurality of walls 23 which define an internal receiving space 2, which serves to receive dishes 3. For this purpose, for example, one or more dish racks 24 are present in the receiving space 2. Furthermore, one or more spray arms 21 are present, with the help of the dishes 3 z. B. during a cleaning step of a wash program with wash liquor 4, ie water or water with cleaning and / or rinse aid, can be applied. For supplying fresh water, the domestic dishwasher 1 is connected via a water inlet 25 with a fresh water network, not shown. Likewise, there is a drain 35, via which the household dishwasher 1 communicates with a sewage network and can be removed via the dirty washing liquor 4 from a sump 22 of the household dishwasher 1. As Figure 1 also shows, an inlet valve 29 and a drain valve 30 is present to control the flow of water or sewage. However, before the rinsing liquor 4 is disposed of via the drain 35, it is usually first performed several times in the circuit, for which purpose a circulating pump 26 is present.

In order to heat the rinsing liquor 4, the domestic dishwasher 1 comprises a heat pump arrangement with an evaporator 5, a compressor 8, a throttle 7 and a condenser 6. If the compressor 8 is activated, the refrigerant present in the region of the compressor 8 becomes gaseous compacted. The compressed refrigerant continues to flow to the condenser 6, where it gives off heat and condenses. The liquid refrigerant then passes to the expansion device 7, which causes a pressure reduction. In the further course, the still or at least partially liquid refrigerant flows to the evaporator 5. There, it extracts heat from the environment and is thereby converted into the gaseous state of aggregation in order finally to return to the evaporator 5 so that the refrigerant circuit closes.

As can now be seen from FIG. 1, the pump sump 22 is connected to the circulating pump 26 via a line. From there, the line continues to a cold water valve 28 and a hot water valve 27. When the hot water valve 27 is closed and the cold water valve 28 is opened, the rinsing liquor 4 conveyed by the circulation pump 26 flows directly to the two spray arms 21. If, however, the cold water valve 28 is closed and the hot water valve 27 is opened, the washing liquor 4 delivered by the circulating pump 26 passes the condenser 6 and absorbs heat there from the condenser 6, provided the compressor 8 is in operation. The rinsing liquor 4 is heated in this way. If the compressor 8 is operated in a period in which the rinsing liquor 4 should not be heated and the condenser 6 therefore does not happen, it is advantageous if the condenser 6 is associated with a heat accumulator 10, in which the heat emitted by the condenser 6 temporarily stored and, if necessary, can be transferred to the rinsing liquor 4, for example, if rinsing liquor is to be heated when the compressor 8 is deactivated.

Furthermore, the domestic dishwasher 1 comprises an air inlet 18, via which air from the environment of the domestic dishwasher 1 can flow into a supply air duct 12 thereof. For an active movement of the air in the direction of the arrow shown in the region of the air inlet 18, a fan 20 is preferably present, which preferably protrudes into or is placed in the supply air duct 12.

If now the fan 20 is operated, then air flows into the supply air duct 12. The invention provides here that the evaporator 5 or one or more heat-conducting sections thereof project into the supply air duct 12 or are in heat-conducting connection with the latter via a heat exchanger. The evaporator 5 is thus capable of extracting heat from the air flowing into the domestic dishwasher 1. If the cooling of the air takes place in such a way that the dew point is undershot, the water vapor entrained in the air condenses. The air is dried with it.

In order to operate the evaporator 5 even when no air flows into the supply air duct 12 (for example during a cleaning step), the domestic dishwasher 1 preferably comprises a heat accumulator 1 1 associated with the evaporator 5. This has before the start of a wash program, the temperature of the environment. During operation of the heat pump arrangement, said heat accumulator 11 can finally deliver heat to the evaporator 5 in order to effect evaporation of the refrigerant.

In the further course, the air continues to flow through the supply air duct 12 until it enters the receiving space 2 via an inlet opening 34. There it comes in contact with the items to be washed 3 and can absorb water from the items to be washed 3 by drying them before and allow it to dry. Preferably, the fan 20 is therefore also operated during the drying step. Finally, the domestic dishwasher 1 has an outlet opening 32 of the receiving space 2, over which the water-enriched air in an exhaust air duct 13 and a arranged at the end of the exhaust duct 13 Luftaus- outlet 19 can escape from the domestic dishwasher 1.

In order to lower the relative humidity R before entering the air into the receiving space 2 and thus effect a more effective drying of the dishes 3, the domestic dishwasher 1 further comprises an air heat exchanger 9, in the heat of the air flowing from the receiving space 2 on the in the receiving space 2 flowing air is transmitted (the air flowing from the receiving space 2 air is due to the hot or hot items 3 usually much warmer than the air flowing into the receiving space 2).

The air heat exchanger 9 may be a separate element through which the air is passed. For example, it could have one or more channels for the incoming or one or more channels for the outflowing air. However, a solution is particularly preferred in which a section 15 of the supply air duct 12 and a section 16 of the exhaust air duct 13 jointly form the air heat exchanger 9. In this case, the common wall of supply air duct 12 and exhaust duct 13 serves as a heat conducting element 17. Of course, it is also possible that the heat conducting element 17 is formed by a separate component.

Likewise, it is conceivable that the air heat exchanger 9 has an insulation 31, for example in the form of a jacket, in order to prevent unwanted heat emission into the environment of the air heat exchanger 9. In any case, the air heat exchanger 9 serves in addition to the cooling of the effluent from the receiving space 2 air at the same time for drying the same. Since the air flowing through the supply air channel 12 was cooled by the evaporator 5 to a fairly low air temperature T (of, for example, between + 0.1 ° C and + 10 ° C), it is also suitable, by heat absorption through the exhaust duct 13th Cooling air to cool relatively strong. This eventually leads to the condensation of entrained in this air of water vapor, so that the absolute humidity A drops. The resulting condensate can, as well as the accumulated in the evaporator 5 condensate collected by means of condensate discharges 14 and z. B. be disposed of via the drain 35 from the household dishwasher 1. Finally, Figure 1 shows that the household dishwasher 1 of course also includes a control and / or regulating unit 33, with which the active components (eg, the drain pump, the fan and the compressor 8) can be controlled and / or regulated.

FIG. 2 shows an exemplary profile of the air temperature T during a drying step along the path of the air. The appropriate relative humidity R (solid line) and the absolute humidity A (= water content) (dashed line) of the air are shown in FIG. The numbers in the area of the X-axis represent the reference numbers shown in FIG. First, the air introduced via the air inlet 18 is cooled at the evaporator 5, wherein water vapor present in the air is partially condensed. The air after the evaporator 5, d. H. 1 in the region of the fan 20, therefore, has a lower air temperature T than in the region of the air inlet 18. At the same time the relative humidity R is 100% higher, the absolute humidity A by the condensation lower than the air in the region of the air inlet 18th

When passing through the air heat exchanger 9, the air is reheated, the air temperature T in the region of the inlet opening 34 of the receiving space 2 is thus higher than in the region of the fan 20. Since there is no condensation of water vapor in the area of the air heat exchanger 9, the absolute humidity remains A equal, the relative humidity R decreases, however.

Within the receiving space 2, the air is heated by the hot items 3. The air temperature T in the region of the outlet opening 32 of the receiving space 2 is therefore higher than in the region of the inlet opening 34. By the water absorption of Spülgut 3 and the absolute and the relative humidity R is increased.

Finally, there is a cooling of the air in the area of the air heat exchanger 9. The air temperature T drops so far that water vapor condenses, connected to the Increasing the relative humidity R to 100% and a reduction in the relative humidity R.

Possible values are:

- Temperature in the area of the air intake: 20 ° C

Relative humidity in the area of the air intake: 50%

Temperature in the area of the evaporator: 0 ° C

Temperature inside the storage room: 50 ° C

Relative humidity inside the recording room: 90%

- Cooling of the air in the air heat exchanger: 5 ° C

This results in a dehumidification rate of 83 g per cubic meter of blown air. Figure 3 also shows that the effluent air is slightly less water, d. H. a lower absolute humidity than the ambient air contains. This is positive for the indoor climate. In Figure 2, the influence of the heat of condensation was not taken into account, so that in reality a higher outlet temperature of the air will result.

The invention relates in one aspect to a dishwasher (domestic dishwasher) having a heat pump and improved drying function.

Much of the energy consumption of a dishwasher is due to the warming of the water and the dishes to be cleaned (ware) conditioned and then to dry it. As a rule, this is realized by means of an electric heater. A heat pump has the advantage over an electrical resistance heater that an equal heating with less electrical work can be achieved. The evaporator, which extracts the required heat from the environment, can be provided with a latent heat storage or run as a finned evaporator with fan. The actively ventilated version has the disadvantage that the air in the kitchen is noticeably cooled. In contrast, the latent heat storage regenerated only slowly why a re-operation of the dishwasher is possible only after a certain time.

According to the present invention, the cooling on the evaporator can be used for the drying after the end of the rinsing process. At the beginning of the rinsing process z. B. the compressor of the refrigeration circuit is turned on, which cools the evaporator with possibly associated latent heat storage and heats the condenser and its possibly existing memory. At an evaporation temperature below 0 ° C, the latent heat storage can be on the low pressure side water, the condenser is z. B. paraffin conceivable. When the operating temperature of the condenser is reached, it heats the water which is drawn in by the pump via the sump and reaches the interior through the spray arms, where it cleans the dirty dishes. From there, the water returns to the swamp. If the water is not to be reheated, the condenser can be bypassed by switching the optional cold and hot water valves accordingly. The discharge of dirty water via the sewer valve. The compressor of the refrigeration cycle can be switched off as soon as enough heat has been transported to heat the water into the latent heat storage tank.

After the end of the actual rinsing process, the dishes must be dried. For this purpose, the fan (fan) can be turned on and the air from the environment flows through the evaporator and the countercurrent heat exchanger into the interior. On the evaporator, the air is cooled to the evaporation temperature. Due to the falling below the dew point separates from the evaporator water, which can be discharged through a drain. This reduces the absolute humidity while the relative humidity is now 100% due to the low temperature. In the subsequent (countercurrent) heat exchanger, the air is heated by the exhaust air, so that at a constant absolute humidity, the relative humidity decreases. This now very dry air enters the interior and allows effective drying of the washed dishes. The exhaust air enters the environment via the countercurrent heat exchanger. As it cools down there, the absolute humidity decreases and the water separated there flows off.

Using a heat pump to heat the water reduces the energy consumption of the device. In addition, the cold generated on the evaporator side is used for drying the dishes. This makes the drying process faster and more efficient. The structure reduces the moisture input into the ambient air, which has a positive effect on the indoor climate of the kitchen. 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 useful, object of the invention.

LIST OF REFERENCE NUMBERS

1 . Domestic dishwasher

2nd recording room

3. Washware

4. rinsing liquor

5. evaporator

6. Condenser

7. Expansion organ

8. compressor

9. Air heat exchanger

10. the condenser associated heat storage

1 1. the evaporator associated heat storage

12. Supply air duct

13. exhaust duct

14. Condensate drainage

15. Section of the supply air duct

16th section of the exhaust duct

17. Heat conducting element

18. Air intake

19. Air outlet

20. Fan

21. spray arm

22nd pump sump

23. Wall of the household dishwasher

24. Crockery basket

25th water supply

26. Circulation pump

27. Hot water valve

28th cold water valve

29 inlet valve

30 drain valve

31. Insulation

32. Outlet opening of the receiving space Control and / or regulating unit inlet opening of the receiving space drain

air temperature

relative humidity

absolute humidity

Claims

Method for operating a domestic dishwasher (1) as part of a wash program, wherein the wash program comprises a cleaning step, during which in a receiving space (2) of the domestic dishwasher (1) arranged wash ware (3) with heated wash liquor (4) is acted upon, and wherein the Rinsing program includes at least one time step subsequent to the cleaning step drying step, during which air flows into the receiving space (2), there receives water from the items to be washed (3) and finally leaves the receiving space (2), characterized in that the household dishwasher (1) a Heat pump assembly comprising an evaporator (5) for evaporating a refrigerant and with a condenser (6) for condensing the refrigerant, wherein the heat pump assembly is at least temporarily operated before and / or during the drying step, during the drying step, heat from the in the direction of air space (2) is transferred to the evaporator (5) and / or to the evaporator (5) associated heat accumulator (1 1), and wherein the domestic dishwasher (1) comprises an air heat exchanger (9), by means of which during the Drying step is transferred at least temporarily heat from the receiving space (2) leaving the air in the receiving space (2) flowing air.

Method according to the preceding claim, characterized in that, during the drying step, at least temporarily so much heat is transferred from the air leaving the receiving space (2) to the air flowing into the receiving space (2) that water vapor present in the receiving space (2 ) leaving air, outside the receiving space (2) at least partially condensed.

Method according to one of the preceding claims, characterized in that the air leaving the receiving space (2) and the air flowing into the receiving space (2) flow in countercurrent through the air heat exchanger (9).

Method according to one of the preceding claims, characterized in that during the drying step at least temporarily so much heat is transferred from the air flowing into the receiving space (2) to the evaporator (5) that water vapor contained in the air outside the receiving space (2) condensed.

Method according to one of the preceding claims, characterized in that the air emerging from the air heat exchanger (9) is discharged from the domestic dishwasher (1), without previously again reach the receiving space (2).

Method according to one of the preceding claims, characterized in that the heat pump assembly is operated at least temporarily during the cleaning step, wherein in this case heat from the condenser (6) to the condenser (6) associated heat storage (10) and / or in the domestic dishwasher (1 ) existing or in the household dishwasher (1) inflowing water is transferred.

Method according to one of the preceding claims, characterized in that the heat pump assembly is operated at least temporarily during the cleaning step, wherein in this case heat from a the evaporator (5) associated heat storage (1 1) is transferred to the evaporator (5).

Household dishwasher (1) having a receiving space (2) for receiving items to be washed (3), wherein the domestic dishwasher (1) comprises a heat pump assembly with an evaporator (5) for evaporating a refrigerant and with a condenser (6) for condensing the refrigerant, wherein the domestic dishwasher (1) has a supply air duct (12) through which air can flow into the receiving space (2) during a drying step of a washing program, and wherein the household dishwasher (1) has an exhaust duct (13) through the air during the drying step the receiving space (2) can flow, characterized in that with the aid of the heat pump assembly heat from the over the supply air duct (12) in the receiving space (2) flowing air to the evaporator (5) is transferable, and / or that the domestic having a heat exchanger (1 1) associated with the evaporator (5), wherein heat from the air flowing into the receiving space (2) on the heat exchanger (1) associated with the evaporator (5) is transferable, and that the household dishwasher (1) comprises an air heat exchanger (9) by means of which heat from the air leaving the receiving space (2) via the exhaust air duct (13) can be transferred to the air flowing via the supply air duct (12) into the receiving space (2).

9. domestic dishwasher (1) according to the preceding claim, characterized in that the domestic dishwasher (1) has at least one condensate discharge (14), with the aid of condensate can be discharged, in the region of the air heat exchanger (9) and / or in the region of the evaporator (5) arises.

10. domestic dishwasher (1) according to claim 8 or 9, characterized in that the air heat exchanger (9) comprises a portion (15) of the supply air duct (12) and a portion (16) of the exhaust duct (13), said portions (15 16) are in heat-conducting contact with each other directly or with the interposition of a heat-conducting element (17).

1 1. Domestic dishwasher (1) according to one of claims 8 to 10, characterized in that the household dishwasher (1) comprises a fan (20) by means of which air through the supply air duct (12) and / or the exhaust duct (13) is movable.

12. domestic dishwasher (1) according to one of claims 8 to 1 1, characterized in that the domestic dishwasher (1) has an air inlet (18) through which during the drying step, air in the household dishwasher (1) can occur, and that the domestic dishwasher (1) has an air outlet (19) through which air can escape from the domestic dishwasher (1) during the drying step.

13. domestic dishwasher (1) according to the preceding claim, characterized in that the air inlet (18) via a supply air duct (12) with the Receiving space (2) and the receiving space (2) via the exhaust duct (13) to the air outlet (19) is connected, so that via the air inlet (18) from the environment of the domestic dishwasher (1) in the domestic dishwasher (1) incoming air over the supply air channel (12) into the receiving space (2) and exiting from the receiving space (2) exiting air via the exhaust duct (13) from the receiving space (2) and via the air outlet (19) from the domestic dishwasher (1) can escape.

14. Domestic dishwasher (1) according to one of claims 8 to 13, characterized in that the domestic dishwasher (1) has a condenser (6) associated heat storage (10) in such a manner with the condenser (6) is in operative connection, during the operation of the heat pump assembly heat from the condenser (6) to the condenser (6) associated heat storage (10) is transferable, and / or that the domestic dishwasher (1) the evaporator (5) associated heat storage (1 1), the like is in operative connection with the evaporator (5) that during operation of the heat pump assembly heat from the evaporator (5) associated heat storage (1 1) on the evaporator (5) is transferable.

15. Domestic dishwasher (1) according to one of claims 8 to 14, characterized in that the domestic dishwasher (1) has a control and / or regulating unit (33) which is designed, the domestic dishwasher (1) according to one of claims 1 to 7 to operate.