KR20100023860A - Domestic appliance, in particular dishwasher, with a heat exchanger - Google Patents

Abstract

The invention proposes a domestic appliance, such as a washing machine, a dishwasher or the like, which permits process heat to be reused by a flow-type heat exchanger (6) for energy-saving purposes.

Description

Household appliances with heat exchangers, especially dishwashers {DOMESTIC APPLIANCE, IN PARTICULAR DISHWASHER, WITH A HEAT EXCHANGER}

The present invention relates to a household appliance, in particular a dishwasher, having a heat exchanger according to the preamble of claim 1.

As consumers' interest in the energy consumption of household appliances such as dishwashers gradually increases, the demand for reducing the energy demand of such household appliances increases.

Published DE 32 27 591 discloses household appliances, in particular dishwashers, in which a heat exchanger is used between waste water and clean water. In this heat exchanger, a transfer medium is used which is guided in one circuit with phase transition to extract heat from the hot water tank and supply it to the cold water tank.

On the contrary, it is an object of the present invention to present a less complicated household appliance, in particular a dishwasher, in production.

This object is achieved by a feature based on a household appliance, in particular a dishwasher, according to the preamble of claim 1.

The features mentioned in the dependent claims enable preferred embodiments and refinements of the invention.

Correspondingly, a household appliance equipped with a heat exchanger according to the invention, in particular a heat exchanger of a dishwasher, is a flow-type in which heat can be transferred by one or more separation walls between the fluid stream to be heated and the fluid stream to be cooled. It is characterized in that the heat exchanger.

Such heat exchangers, which can be formed, for example, as direct-current heat exchangers, counter-flow heat exchangers, cross-flow heat exchangers, can be integrated much more simply in the fluid circuit of household appliances, in particular dishwashers.

In this case, a counterflow heat exchanger is preferably used, because higher efficiency can be realized during heat transfer.

The use of waste heat according to the invention is intended to facilitate the transfer of heat from heated fluids, in particular detergents or wash liquors, to be discharged from household appliances, in particular dishwashers, for example using heat exchangers to transfer waste heat to new fluids required for further process steps. It is possible by being done.

By utilizing waste heat using a heat exchanger, the fresh fluid supplied from the supply line network, for example water purification, can be preheated by the waste heat of the waste fluid, so that the energy demand of the household appliance is greatly reduced.

Preferably the flow through heat exchanger is at least partly made of plastic. This reduces manufacturing costs. Heat exchangers made of plastic are typically plastics used in the home appliance area, but have lower efficiency than metal heat exchangers, but because of the cost savings, such heat exchanger technology can be used in home appliances as mass production, whereby Significant energy savings can be realized in the operation of the equipment, even at low efficiency.

Preferably in the household appliance according to the invention there is also provided a storage tank for the fluid heated through the heat exchanger. This makes it possible to carry out heat exchange at an earlier point in time when the heated fluid is not yet needed as the process fluid. The heated fluid is stored in the storage tank for this purpose and provided at a later point in time. The process of heat exchange is separated in time from this storage tank from the point at which process heat is generated that can no longer be needed and can be reused, and from the point at which it is essential to obtain a fluid that can be heated using waste heat.

In an improvement of the invention there is provided a storage tank for intermediate storage of the waste fluid to be discharged. With this storage tank for waste fluid, the heat exchange for using waste heat can be separated in time from the point of discharge of the waste fluid. Thereby, the point of use of the waste heat is deferred to another point in time, in this case a later point in time, for example when a new fluid is needed.

When two storage tanks are used, the heat exchange is completely separated from other working processes of the household appliance not only for the heated fluid but also for the heated waste fluid to be discharged.

Each manner in which household appliances, especially dishwashers, are separated in time from the work process can be utilized to improve the use of waste heat. In this case, the above-mentioned temporal separation, for example in the case of using one or a plurality of storage tanks described above, can be preferably used even in the case of using a conventional heat exchanger made of a metallic material.

In an improvement of the invention the use of waste heat is improved by adjusting the volumetric flow of fluid to be cooled and / or heated to the rate of heat transfer in the heat exchanger.

Due to this, the amount of thermal energy transferred in the heat exchanger may increase. This is particularly advantageous when the heat exchanger is used at inherently low efficiency, so that heat exchange through a longer contact time or less volume flow of fluid is also possible in a heat exchanger with a lower efficiency, for example a plastic heat exchanger.

In this case, the adjustment of one or a plurality of volume flows through the heat exchanger is possible as described above in the context of the one or more storage tanks, in particular in a household appliance, in particular a dishwasher, according to the invention. The heat transfer is separated in time from, for example, the point of time at which the purified water is obtained or the time at which the detergent to be discharged is produced, so that the period for heat transfer is provided much longer than in a device without this type of time separation. Since the overall duration of the cleaning program should be kept as short as possible, the duration for which clean water is to be obtained or for which the waste cleaning liquid has been pumped out is relatively short. When one or a plurality of storage tanks for intermediate storage are used, the programming steps in the working process of household appliances, in particular dishwashers, can be made during the heat transfer through the heat exchanger, so much more for inherent heat transfer to use waste heat. Longer periods are provided.

Such an increase in waste heat utilization through adjustment of the volume flow is possible, in particular when the volume flow is controllably formed in accordance with the rate of heat transfer in the heat exchanger. Such an increase in one or more volumetric flows allows for individual adjustments to the respective heat exchange process, e.

Heat exchangers according to the invention, in particular heat exchangers of plastics material, can also be used to utilize waste heat from a fluid flow different from the working fluid to be discharged, for example waste heat in a closed circuit of the drying apparatus. Such a heat exchanger is provided, for example, in the household appliance, in particular in the dishwasher, where the process heat during operation of the household appliance is utilized and a cooling device for drying the condensed dishware via condensation is utilized when utilizing the heat provided for the cooling unit. Can be preferably used.

In a particular embodiment of the invention, the medium comprising hot or cold air in the circuit is forced through a heat exchanger, for example by a circulation pump. In this case, such a medium may be a working fluid for normal working evacuation in the working chamber interior space of the household appliance, but may also be a medium specially provided for storing hot or cold air.

In addition, the use of waste heat by the heat exchanger according to the present invention can be usefully used in many home appliances, such as a washing machine, the fluid is guided. However, use in household appliances, in particular in dishwashers, is particularly preferred, since in a relatively short working cycle, the working fluid, ie the washing or rinsing liquid, is replaced by obtaining the purified water completely or partially.

Embodiments of the invention are shown in the drawings and are explained in more detail below by means of the drawings.

1 is a schematic block circuit diagram of the present invention in a dishwasher.

2 is a schematic block circuit diagram of a further embodiment of the present invention.

3 is a schematic block circuit diagram of an improvement on the embodiment according to FIG. 2.

4 is a schematic block circuit diagram of a further embodiment.

1 shows a working chamber 1 of a household appliance, in particular a dishwasher, having a purified water inlet 2 and an outlet 3 through which no longer required washing or rinsing liquid can be discharged.

The purified water supply according to the illustrated embodiment takes place via a shut-off valve 5 from a purified water connection 4 in contact with the purified water supply line network and a heat exchanger 6 formed as a perfusion heat exchanger according to the invention. The purified water is preheated in the heat exchanger 6 and then stored intermediately in the storage tank. The purified water can be introduced into the working chamber 1 of the dishwasher at the required time by an additional shutoff valve 5.

Discharge of the corresponding working fluid, eg rinse or wash liquid, is carried out in the manner described below, with the optional parts shown inside the dashed rim.

The detergent pump 9 supplies the fluid to be discharged, for example washing liquid or rinsing liquid, into the heat exchanger 6, which is then discharged through the wastewater connection 10 into the wastewater network.

When passing through the heat exchanger 6, the process heat from the dishwasher working chamber 1 is released to the purified water reaching through the purified water connection 4 and then reused as process heat in the storage tank 7. Is provided.

Optionally, the discharge portion may be provided with a storage tank 11 for receiving a fluid to be discharged, for example a washing liquid or a rinsing liquid. In this case, this storage tank 11 is used to some extent as a heat exchanger. Perfusion of the liquid through the heat exchanger 6 can be started by switching of the shutoff valve 12.

Each of the storage tanks 7, 11 can separate the heat exchanger from the working process of the various apparatuses assigned according to the embodiment of the invention in time. The storage tank 7 allows the purified water to be supplied to the appliance at this point, even when the purified water is not needed in the working chamber 1 at the desired time. Although no purified water is required, the purified water can be stored in the storage tank 7 in a preheated state via the heat exchanger 6 at a pre-switched time point.

This heated liquid is stored in the storage tank 11 as a heat reservoir, whereby the storage tank 11 generates a temporal separation from the point of discharge of the working fluid, for example a washing liquid or a rinsing liquid. The stored heat can then be transferred through the heat exchanger 6 at a later point in time, for example when an integer has to be obtained. In this case, the two storage tanks 7 and 11 can exert respective advantages described above, irrespective of each other, so that they are not necessarily used in common, and can also be used independently in one embodiment.

If two storage tanks 7, 11 are provided, the heat exchange process is sufficiently separated from the working process of the apparatus. This results in a greater degree of freedom in regulating the volumetric flow, for example, to improve heat exchange in the heat exchanger 6.

For example, the volume flow of liquid to be discharged or newly obtained liquid in the heat exchanger 6 can be adjusted by correspondingly adjusting the cross-sectional area of the line, for example the shut-off valve 5 and / or the shut-off valve 12. .

If the shutoff valve 5 and / or the shutoff valve 12 are controllably formed, this allows the respective volumetric flow through the heat exchanger 6 to be controlled. Basically this controllable volume flow can also be achieved through pressure control, for example the control of the detergent pump 9 or other forms of pumps not included in the illustrated embodiment. When controlling via the detergent pump 9, for example, a pressure affecting the volume flow through the heat exchanger 6 can be applied to the liquid to be extracted.

The use of the heat exchanger 6 allows for significant energy savings, with relatively low manufacturing complexity and thus low costs in the operation of the relevant household appliance. With a combination of one or a plurality of storage tanks 7, 11, the use of the heat exchanger 6 is improved by separating the heat exchange process in time from one or a plurality of process steps of the household appliance.

By adjusting one or two volume flows through the heat exchanger 6, the degree of freedom of heat exchange is affected. In particular, the low degree of freedom of the heat exchanger, for example made of plastic, can thus be at least partly compensated.

The variant according to FIG. 2 corresponds mostly to the embodiment described above. In this case, the heat exchanger 13 is different from the inside of the storage tank 7. In addition, the working fluid is forcibly guided in the circuit by the detergent pump 9. As such, for example, the washing liquid may be pumped through the heat exchanger 13 in a closed circuit. In this case, the storage tank 7 can be provided for example for the reception of purified water, which is indicated by the purified water connection 4. However, in this case it is also possible to use other heat storage media.

Since the detergent circuit is provided with a three-way valve 14, the circulated working fluid may be pumped out of the circuit. The storage tank 7 is connected to the circuit guide via a shutoff valve 15 and a connection line 16, so that fluid present in the storage tank can be supplied to the circuit in some cases.

In this embodiment the working liquid, eg purified water, to be heated in the storage tank 7 can be stored intermediate and heated for a longer period of time through the circulated working liquid, for example a washing liquid. The heat exchanger 13 can therefore also have a lower efficiency, for example formed as a plastic heat exchanger. Sufficient heat transfer is ensured in this way with the longest possible delivery time.

The storage tank 7 may, in another embodiment, be provided completely separate from the circuit of the working liquid, i.e. without the connecting line and the shutoff valve 15, and may be provided independently of other operations of the household appliance and to be replaced if necessary. It may comprise a pure heat storage medium.

The storage tank 7 may also contain other working liquids, for example, already prepared rinse liquids heated through the working liquid circulated in a closed circuit.

3 shows a variant which can be compared with the embodiment according to FIG. 2, in which the heat exchanger 6 is again arranged separately from the storage tank 7. In this variant, the second circuit through the heat exchanger 6 is pumped by an additional circulation pump 17. In this case, various possibilities of use of the storage tank 7 associated with the heat exchanger 6 are given as in the above-described embodiment.

As long as the second circuit comprising the storage tank 7 has to be combined with the first circuit comprising the working chamber 1 of the household appliance, for example, connecting the fluid from the storage tank 7 to the connection line 19. A three-way valve 18 can be provided which can be fed into the working chamber 1 through.

The second circuit can likewise be selectively opened for the discharge of the working liquid. In the embodiment described above this is done via a second three-way valve 20 for pumping out working liquids, for example washing fluid or the like, in the circuit.

In the fourth embodiment according to FIG. 4, there are again two closed circuits, on the one hand which can be circulated through the detergent pump 9 under the inclusion of the working chamber of the household appliance, and on the other hand the storage tank 7. A variant of the circuit having a circuit circulated through the circulation pump 17 is shown. Two circuits are guided through the heat exchanger 6. In this variant, in the storage tank 7 there is arranged a pure heat storage medium for intermediate storage of heat from the working chamber 1 of the household appliance and, if necessary, for discharging.

The variant with two circulation pumps 9, 17 has the advantage that it is possible to control not only the circulation duration but also the circulation rate and circulation volume via the heat exchanger 6. In this way the heat exchange can be improved via this control parameter, which is advantageous in particular in a heat exchanger 6, for example a plastic heat exchanger, which does not include maximum efficiency, depending on the design scheme.

A further unillustrated variant uses a solid heat reservoir in thermal contact with the guided working fluid in the circuit instead of the circulating storage fluid by the storage tank.

In addition to the illustrated embodiment, any further embodiments are contemplated, and a substantial element of the invention is the possibility of interim storing waste heat from the household appliance and providing it again to the working process of the household appliance at a later point in time.

<Drawing code list>

1: working chamber

2: purified water inlet

3: discharge part

4: integer connection part

5: shut-off valve

6: heat exchanger

7: storage tank

8: shutoff valve

9: detergent pump

10: wastewater connection

11: storage tank

12: shutoff valve

13: heat exchanger

14: 3-way valve

15: shutoff valve

16: connection line

17: circulation pump

18: 3-way valve

19: connecting line

20: 3-way valve

Claims (18)

In household appliances, especially dishwashers, having a heat exchanger for reusing process heat, The heat exchanger (6) is a household appliance, in particular a dishwasher, characterized in that the heat-type heat exchanger is capable of transferring heat by at least one separating wall between the fluid stream to be heated and the fluid stream to be cooled. 2. Appliances according to claim 1, characterized in that the heat exchanger (6) is at least partly made of plastic. In a fluid guided household appliance, in particular a dishwasher according to the preamble of claim 1, A household appliance, in particular a dishwasher, characterized in that a storage tank 7 is provided for intermediate storage of fresh fluid heated through the heat exchanger 6. Appliances, in particular dishwashers, according to one or more of the preceding claims, characterized in that a storage tank (11) is provided for intermediate storage of the heated waste fluid to be discharged. Appliances, in particular dishwashers, according to one or more of the preceding claims, characterized in that the volumetric flow of fluid to be cooled and / or heated is adapted to the rate of heat transfer in the heat exchanger (6). 6. Appliances, in particular dishwashers, according to one or more of the preceding claims, characterized in that the volumetric flow of fluid to be cooled and / or heated is controllable in accordance with the rate of heat transfer. Appliances, in particular dishwashers, according to one or more of the preceding claims, characterized in that a cooling device (101) is provided for drying the moist washed object. 8. A household appliance, in particular a dishwasher according to claim 1, wherein at least one fluid is guided through a heat exchanger for heat transfer of process heat in a closed circuit. 9. Appliances, in particular dishwashers, according to one of the preceding claims, characterized in that a closed fluid circuit is provided comprising a heat exchanger (6) and a storage tank (7). 10. Appliances, in particular a dishwasher according to one of the preceding claims, characterized in that the liquid heat storage medium is stored in a storage tank (7). 11. A household appliance, in particular a dishwasher, according to any one of the preceding claims, characterized in that the heat exchanger is provided in a solid heat reservoir. 12. A household appliance, in particular a dishwasher, according to any one of the preceding claims, characterized in that a solid heat storage body is provided. In a method for reusing process heat inside a fluid guided household appliance, in particular a dishwasher, a washing machine, etc., A flow-through heat exchanger is provided for reusing process heat. The method of claim 13, wherein the fresh fluid to be supplied is heated through a heat exchanger. 15. The method of claim 13 or 14, wherein the heated fresh fluid is intermediately stored for later use. 16. The method according to any one of claims 13 to 15, wherein the waste fluid is stored intermediate before being discharged. The method of claim 13, wherein the volumetric flow of the waste fluid to be cooled through the heat exchanger and / or the fresh fluid to be heated is adapted to the heat transfer rate. 18. The method according to any one of claims 13 to 17, wherein the volumetric flow of waste fluid to be cooled and / or fresh fluid to be heated is controlled in accordance with the rate of heat transfer in the heat exchanger.

Images