CN106968079B

CN106968079B - Washer-dryer with cooling water circuit

Info

Publication number: CN106968079B
Application number: CN201611107787.7A
Authority: CN
Inventors: H·埃格迈尔; F·陆; H·赖希内尔; G·施利克尔; T·施奈德; A·施托尔策; 冶萍
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2016-01-14
Filing date: 2016-12-06
Publication date: 2021-05-04
Anticipated expiration: 2036-12-06
Also published as: EP3192912A1; EP3192913A1; EP3192913B1; CN106968079A

Abstract

The invention relates to a washer-dryer comprising a tub, a drum rotatably mounted in the tub, a process air circuit comprising a fan and a heater adapted to circulate process air through the drum for drying laundry, a cooling water circuit in contact with the process air circuit, a pump, a condenser and a control unit, wherein the cooling water circuit is in heat-exchanging contact with at least one cooling device adapted to cool cooling water, wherein the washer-dryer comprises two cooling devices selected from the group consisting of a heat exchanger, a cooling air fan and a mains water supply, and a temperature T in the cooling water circuit for measuring the temperature T of the cooling water_WA maximum threshold value T of the cooling water in the cooling water circuit_W,maxStored in the control unit, the control unit being adapted to: operating the pump and/or the two cooling devices until the temperature T of the cooling water_WDown to below T_W,max. The present invention is also directed to a method for operating the washer-dryer.

Description

Washer-dryer with cooling water circuit

Technical Field

The present invention relates to a washer-dryer for washing and drying laundry, comprising a tub, a drum rotatably mounted in the tub, a process air circuit adapted to circulate process air through the drum for drying the laundry, a cooling water circuit in contact with the process air circuit, the process air circuit comprising a fan and a heater, a pump, a condenser and a control unit. Furthermore, the invention relates to a method for operating said washer-dryer.

Background

In recent years, washing-drying machines, i.e., drum type washing machines having a drying function, have been popular among consumers because they are very convenient and compact home appliances since they include washing and drying functions. In addition, commercially available washing-drying machines have been provided with a water supply path so that water can be used not only for washing laundry but also for other process steps. In a washer-dryer, the process air is circulated with the aid of a fan and heated with an air heater. Heated air enters the tub and the drum, where it carries up the moisture contained in the laundry. In order to guide the air in a closed circuit, the washer-dryer is almost exclusively used as a condensation dryer. The hot and humid air leaving the drum is taken away and the moisture is condensed in a so-called condenser, where heat is removed from the process air via cooling. The condensed water is typically collected and drained in the same manner as the wash liquid.

Commercial washer-dryers generally use fresh tap water as a refrigerant in order to cool the hot and humid process air. Due to the condensation of the moisture, the process air is dried and reintroduced into the tub. One problem associated with such commercially available washer-dryers is that a large amount of fresh tap water is consumed during each drying procedure. That is, as the fresh tap water passes through the condenser, the fresh tap water is heated. The hot water is no longer available for cooling purposes and is therefore discarded. Accordingly, there is a need for a washer-dryer that provides more ecologically friendly drying.

Washing-drying machines using tap water are known.

EP 2749682 a1 discloses a washer-dryer comprising a compartment for receiving articles to be washed and dried, a reservoir adapted to contain a fluid, a washer heat pump comprising a refrigerant. The washer heat pump of the washer-dryer is adapted to: cooling the refrigerant in a washing phase, heating water to be used in the chamber, heating the refrigerant and cooling the fluid contained in the reservoir. The washer-dryer further comprises an air cooling/dehumidifying element adapted to cool/dehumidify the process air downstream of the chamber during a drying phase of the washer-dryer. The reservoir or a heat exchanger thermally connected to the reservoir is arranged downstream of the chamber and upstream of the air cooling/dehumidifying element in order to pre-cool/pre-dehumidify process air which exits from the chamber before it is introduced into the air cooling/dehumidifying element.

EP 2216436 a1 discloses a washing-drying machine comprising a washing tub, a reservoir for storing water for use, a drying air line which is arranged outside the washing tub and to whose opposite ends the washing tub is connected for use in a drying program, and an air blowing/heating device which is provided in the drying air line for sucking air out of the washing tub through one of its opposite ends, heating the sucked-out air and returning the heated air back into the washing tub through the other end of the drying air line in the drying program. The washer-dryer further comprises a reservoir water circulation channel comprising a supply channel having opposite ends and a recovery channel having opposite ends, one of the ends of the supply channel being connected to the reservoir and the other being connected to the first location of the drying air line, one of the ends of the recovery channel being connected to the second location of the drying air line or the washing tub, the other being connected to the reservoir. A pump is provided in the reservoir water circulation channel for pumping water from the reservoir through the supply channel for supplying water from the first location into the drying air line and for dropping water through the drying air line for returning water from the second location or the washing tub through the recovery channel to the reservoir for circulating water. The washer-dryer further comprises control means which control the pump so as to circulate a small amount of water through the reservoir water circulation channel in a first half of the drying program and to circulate more water through the reservoir water circulation channel in a second half of the drying program.

Publication US 2013/008049 a1 discloses a drying apparatus based on a heat pump, the drying apparatus comprising: a housing that receives a drum for containing items to be dried by air flowing along a path between an outlet and an inlet of the housing, a fluid being provided in the path to at least partially remove moisture from the air, and a heat pump comprising: a heat source at least partially disposed within the path, a heat sink operatively adapted to accommodate the heat source, and an enclosure at least partially housing the heat sink and arranged to receive fluid from the path so as to exchange heat with the heat sink and return fluid to the path. As shown in fig. 1, hot humid air from the drying chamber enters a process air channel in which the air is contacted with water sprayed from a spray nozzle so as to cool the hot humid air.

Publication EP 1291597 a1 discloses a drying device comprising a drying air circulation circuit comprising: an air intake duct comprising means for heating air; a drying case in which an object to be dried is placed; an outlet duct in which a condenser cooled by a heat transfer fluid is arranged; a circuit for the circulation of a heat transfer fluid, said circuit comprising successively a condenser and a container suitable for storing the heated heat transfer fluid at the discharge from the condenser. Furthermore, a further heat exchanger is arranged in the air circulation circuit upstream of the drying enclosure.

Publication JP 2011194035 a relates to a washing dryer in which, in a drying operation, an increase in the load of a compressor is suppressed by reducing the dehumidification load of an evaporator. Thereby, when the dehumidifying load is increased during the latter half of the drying operation, the capacity of the heating pump unit is maintained, and the heating pump unit is compact. In particular, a ventilation air circuit is formed comprising a ventilation air channel comprising an air supply duct, a discharge duct and a heat exchange duct. A heat absorbing heat exchanger having heat exchange tubes is disposed in the discharge conduit on an upstream side of the evaporator. The heat absorbing heat exchanger is supplied with cooling water in order to cool the circulating air located in the discharge duct.

Publication GB 1247788A discloses a device for dry washing comprising a drying chamber, a condensation space communicating with the chamber, a spray nozzle for introducing water into the condensation space, a cooler and a recirculation pump, the drying chamber comprising a heater, the recirculation pump being arranged to enable water collected in the condensation space to pass through the cooler to the spray nozzle, the chamber and the condensation space being substantially sealed from the outside. Accordingly, the water introduced into the condensation space circulates. As can be seen in the embodiment shown in fig. 2, the water collected in the condensation space is pumped by means of a recirculation pump through the vertical tubes and finally to the spray nozzles, from which the water is sprayed on the steam located in the condensation space. The heat exchange tubes are in contact with air drawn in from the outside by means of a suction fan.

Publication US 2005/0223755 a1 discloses a drying device for a washing machine, comprising: a duct, opposite ends of which are connected to a tub of the washing machine, such that air in the tub passes through the duct and is supplied to the tub again; a fan in the duct for drawing air from the tub and discharging air into the tub; a water supply device connected to the duct for supplying cooling water into the duct so as to condense moisture in air passing through the duct; a heater located in the duct for heating air passing through the duct; cooling water circulating means for resupplying the cooling water, which is maintained at the bottom of the tub after passing through the duct, into the duct. The cooling water circulating means preferably further includes a plurality of fins projecting from the outer circumferential surface for dissipating heat from the cooling water, and the cooling water circulating means preferably further includes a cooling fan for blowing air to the outer circumferential surface of the circulating pipe for cooling the cooling water. The drying apparatus preferably further includes a temperature sensor at the bottom of the tub for measuring the temperature of the cooling water, and the cooling water is preferably circulated or discharged according to the measurement result of the temperature sensor.

Disclosure of Invention

In view of this situation, it is a primary object of the present invention to provide a washer-dryer with improved process air cooling and a method for operating the same, which are capable of reducing tap water consumption.

According to the invention, this object is achieved by a washer-dryer and a method for operating a washer-dryer having the features of the respective independent claims. Preferred and alternative embodiments of the invention are detailed in the respective dependent claims. Even if not mentioned here specifically, a preferred and alternative embodiment of the washer-dryer corresponds to a preferred and alternative embodiment of the method.

The invention therefore relates to a washer-dryer comprising a tub, a drum rotatably mounted in the tub, a process air circuit adapted to circulate process air through the drum for drying laundry, a cooling water circuit in contact with the process air circuit, the process air circuit comprising a fan and a heater, the cooling water circuit thereby being in heat-exchanging contact with at least one cooling device adapted to cool cooling water, a pump, a condenser and a control unit, wherein the washer-dryer comprises two cooling devices and a temperature T measuring device in the cooling water circuit for measuring the temperature of the cooling water_WA first temperature sensor of (1), the cooling device being selected from the group consisting of a heat exchanger, a cooling air fan and a tap water supply device, a maximum threshold value T of cooling water in the cooling water circuit_W,maxStored in the control unit, the control unit being adapted to: operating the pump and/or the two cooling devices until the temperature T of the cooling water_WDown to below T_W,max。

In a washer-dryer, a condenser is typically used to cool and dehumidify hot and humid process air during a drying procedure. Therefore, a condenser is usually arranged in the process air circuit downstream of the tub, the process air reaching the condenser having taken up moisture from the laundry to be dried. In order to circulate the hot and dry process air back into the tub, the moisture must first be removed. In condensers, this is usually achieved by applying a refrigerant to cause condensation, which is thereby triggered by direct or indirect heat exchange contact of the refrigerant with the process air. In the present invention, the refrigerant is a water liquid, particularly water. Since heat is removed from the process air, the cooling water is heated. In order to ensure a good and sufficient cooling efficiency, the cooling water itself must be cooled before being recirculated into the condenser. The cooling of the cooling water can in principle be achieved by simple heat exchange with the environment via natural convection, conduction or radiation (natural cooling). However, in the present invention, a cooling device is used. The type of cooling that can be achieved thereby may also be referred to as "active cooling" as opposed to "natural cooling".

The cooling water circuit thus comprises at least two cooling devices. The at least two cooling devices located in the cooling water circuit are selected from the group consisting of heat exchangers, cooling air fans and mains water supply devices. The heat exchanger is preferably an air-to-air heat exchanger. In this case, the cooling air can also be circulated in the heat exchanger with the aid of a cooling air fan.

In a preferred embodiment, the cooling water circuit comprises a heat exchanger. Strictly speaking, the type of heat exchanger used is not limited as long as the heat exchanger is used to cool the cooling water located in the cooling water circuit. However, the heat exchanger is preferably an air/water heat exchanger, wherein the cooling air is provided by a cooling air fan. The control unit is adapted to controlling the cooling air fan. Preferably, during the drying program, the specific point, duration and speed of operating the cooling air fan are stored in the control unit.

As the cooling water passes through the air/water heat exchanger, the cooling air stream contacts the cooling water circuit, thereby removing heat from the cooling water. Preferably, the air/water heat exchanger is arranged in the cooling water circuit downstream of the condenser outlet. More preferably, the heat exchanger is also arranged close to an outer wall of the washer-dryer casing. In this way, natural cooling can additionally be performed. Even more preferably, the cooling water circuit may comprise two or more heat exchangers.

In another preferred embodiment, the cooling water circuit comprises a mains water supply. One way to realize the tap water supply device may be: the cooling water circuit is connected to the mains water supply via a valve which can be operated by the control unit. Preferably, for cooling the cooling water located in the cooling water circuit, the control unit is adapted to mixing fresh tap water into the cooling water via the respective water supply passage. More preferably, during drying, a specific point and duration of mixing fresh water into the cooling water may be stored in the control unit. For this purpose, the cooling water circuit may additionally be connected to a drain to prevent flooding.

The washer-dryer comprises two cooling devices, preferably a heat exchanger and a mains water supply circuit. If the amount of cooling provided by one cooling device is not sufficient to lower the temperature of the cooling water below the threshold T_W,maxThe control unit is then adapted to additionally operate the second cooling means.

In a preferred embodiment of the washer-dryer, the cooling water circuit comprises a reservoir. The term "reservoir" here refers in particular to a container having an internal cross-section which is larger than the cross-section of the tube normally used in the cooling water circuit. Preferably, the cross-section in the reservoir used is at least five times greater than the cross-section of any tubes used within the cooling air circuit. The reservoir serves the following purposes: increasing the cooling water volume in the cooling water circuit and thereby slowing down the temperature rise of the cooling water in case of insufficient cooling. The size of the reservoir is not limiting in the present invention. Accordingly, the reservoir may be a small, for example even just a part of the cooling water circuit which is enlarged in its diameter. The reservoir may also be of medium or large size. However, the size of the reservoir is generally determined by the design and desired technical capabilities of the washer-dryer. If the reservoir is arranged close to the outer wall of the housing of the washer-dryer, natural cooling of the water inside the washer-dryer may occur. This heat exchange may increase the time required for the cooling water to be heated during the drying process and thus serve to enhance the cooling efficiency of the cooling water circuit.

If a reservoir is used, the reservoir preferably includes a heat sink located on an outer surface of the reservoir. In this way, the heat exchange with the environment is improved, so that the cooling water located in the cooling water circuit can be cooled more efficiently. Preferably, the fins are provided on a portion of the surface closest to the outer wall of the washer-dryer casing. Heat sinks are commonly used to increase the efficiency of natural convection cooling by providing a larger surface area and by directing the flow direction of the air. Thereby, by providing the heat sink, the amount of natural cooling of the water in the reservoir may be even further increased.

If a reservoir is used, the circulation of cooling water may be driven or at least assisted by natural convection, wherein the cold water liquid typically has a higher density than the warmer water liquid. In such an embodiment, warmed cooling water is typically introduced into the upper portion of the reservoir. The more the cooling water is cooled, the more it flows down in the direction of the condenser. This process may be assisted by suitable internal structures in the reservoir. That is, the reservoir may include a plurality of flat components inside. These flat parts can be fixed to the walls of the reservoir, forming a horizontal layer structure along which the cooling water is forced to flow. In a preferred embodiment of the washer-dryer, the reservoir thus comprises an inlet for warmed cooling water at the top, so that natural convection cooling may drive or assist the circulation of cooling water in the flow direction from the inlet of the reservoir.

Even more preferably, the cooling device is arranged at the cooling water inlet of the reservoir, i.e. at a location where the temperature of the cooling water is typically highest. In any event, in this embodiment, the cooling water circuit may operate without operating a pump therein. At least the power consumption of the pump can be reduced.

In a preferred embodiment, the washer-dryer comprises a washing liquid recirculation system, the pump being connected to the cooling water circuit and to the washing liquid recirculation system, such that the pump is operable by the control unit to circulate water in the cooling water circuit or the washing liquid recirculation system. For this purpose, a suitable three-way valve may be arranged in the recirculation system.

The control unit may additionally be adapted to: before the drying program starts, the pump is operated and the cooling water circuit is filled with washing liquid or, more suitably, with rinsing liquid from the last rinsing step. Accordingly, a rinse liquid, which is typically water containing only a small amount of detergent, may be used as cooling water in this embodiment. In this way, the water used to wash and/or rinse the laundry may be reused. This enables to reduce the overall water consumption of the washer-dryer even further.

In a further preferred embodiment, the cooling water circuit further comprises a water supply valve, which can connect the cooling water circuit with the mains water supply and which is controlled by the control unit. This embodiment is particularly useful if the temperature of the cooling water becomes too high despite the use of other cooling means, so that the use of other cooling means is not sufficient.

In order to be able to operate the washer-dryer more efficiently, the washer-dryer comprises a temperature T for measuring the cooling water in the cooling water circuit_WThe first temperature sensor of (1). Preferably, the temperature T of the cooling water_WThe relation with the flow rate of the pump and/or the cooling capacity of the cooling device is in this case stored in a control unit adapted to: based on this relationship, the flow rate of the pump and/or the cooling capacity of the cooling device is controlled. More preferably, the optional first temperature sensor is arranged at the cooling water inlet of the condenser, but other locations are possible.

Maximum threshold value T of cooling water in cooling water circuit_W,maxStored in a control unit adapted to: the pump and/or the at least one cooling device are typically operated by increasing the power of the pump and the cooling device until the temperature T of the cooling water_WDown to below T_W,max. Temperature sensor usedThe type of (c) is not limited. However, the first temperature sensor is more preferably an NTC temperature sensor.

In another preferred embodiment, the washer-dryer comprises a temperature T for measuring the process air in the process air circuit_PThe control unit is adapted to: at a temperature T_PReach the set minimum threshold value T_P,minWhen operating the pump and/or the cooling device in the cooling water circuit. The type of the temperature sensor is also not limited. However, the second temperature sensor is more preferably also an NTC temperature sensor. Generally, it is disadvantageous to cool the process air during the heating phase, since this will prolong this phase and thus the entire drying program. Preferably, the minimum threshold T_P,minIs stored in the control unit. If the second temperature sensor detects that the temperature of the process air reaches the threshold value T_P,minThe control unit is then adapted to: for example, a pump in the cooling water circuit is operated to pump cooling water through the cooling water circuit and cool the process air located within the condenser. It is also preferred that the maximum threshold T is_P,maxIs stored in the control unit. If the second temperature sensor detects the temperature T of the process air_PExceeds T_P,maxThe control unit is then adapted to: increasing the pumping speed and thus the flow rate of cooling water in the cooling water circuit, and/or operating the at least one cooling device.

In another embodiment of the washer-dryer the cooling water circuit is a closed cooling circuit, wherein the cooling water is not in direct contact with the process air in a condenser located in the process air circuit. In this embodiment, the cooling circuit pump is preferably provided in a closed cooling water circuit. For this purpose, the washer-dryer may be provided with a second pump. However, it is also possible to use only one pump, i.e. a pump which is normally used for pumping washing and rinsing liquid.

In this embodiment, the cooling water circuit preferably forms at least one coil within the condenser to serve as a condensing coil for the process air flowing through the condenser. In an even more preferred embodiment, the cooling water circuit forms a plurality of condensing coils within the condenser. This increases the surface area through which the process air flows and is cooled. Thereby, the cooling of the process air may be faster and more efficient.

In an alternative embodiment, the cooling water circuit is an open cooling water circuit, wherein the cooling water is in direct contact with the process air in the condenser. Preferred for efficient heat exchange are: the open cooling water circuit comprises a nozzle which is arranged within the condenser and enables direct contact between the cooling water and the process air in the condenser located in the process air circuit. That is, the cooling water directed through the cooling water circuit may be directly sprayed into the process air. Thereby, the process air is directly exposed to the cooling water, thereby forming liquid droplets. This manner of establishing contact between the process air and the cooling water circuit is referred to herein as direct contact. Preferably, at the outlet of the condenser, the cooling water is collected and reintroduced into the cooling water circuit. The collection container may be a separate container. But more preferably the cooling water is collected in a tub of the washer-dryer, said tub being part of the open cooling water circuit.

The washer-dryer of the invention can thus be operated in essentially two different ways, wherein the cooling water circuit operates as a closed cooling circuit or as an open cooling circuit. However, both principles can also be combined. This combination can be achieved by: a portion of the pipes of the substantially open cooling water circuit is arranged in the washer-dryer such that heat exchange between the pipes and the process air circuit is possible.

The type of condenser used according to the present invention is not limited. Depending in particular on the type of cooling water circuit, the condenser may be a separate component or an integrated part of a component of the washer-dryer, for example, if the cooling water circuit is an open cooling water circuit, the condenser may be a space behind the tub in which the hot, moist process air is in direct contact with the cooling water, preferably in which water is sprayed via nozzles against the flow direction of the hot, moist process air. In contrast, in a closed cooling water circuit, the condenser may be a separate unit which may be in close contact with the wall of the tub, or which may have a suitably formed surface located within the process air circuit, so as to enable efficient heat exchange between the cooling water and the hot, moist process air through the wall of the condenser.

Generally, the drying operation includes three stages: a heating stage, a main drying stage and a cooling stage. During the heating phase, the temperature T of the process air_PGenerally increasing over time. Once the process air has reached a certain temperature according to the selected drying program, the temperature T of the process air_PIt remains unchanged and the main drying program is reached. During the main drying process, most of the moisture is removed from the laundry within the drum. The primary drying stage is followed by a cooling stage. During the cooling phase, only the residual moisture has to be removed from the laundry. In the cooling phase, the temperature T of the process air_PUsually again until the drying program is finished.

The invention is also directed to a method for operating a washer-dryer comprising a tub, a drum rotatably mounted in the tub, a process air circuit adapted to circulate process air through the drum for drying laundry, a cooling water circuit in contact with the process air circuit, the process air circuit comprising a fan and a heater, wherein the cooling water circuit is in heat-exchanging contact with at least one cooling device adapted to cool cooling water, a pump, a condenser and a control unit, wherein the washer-dryer comprises two cooling devices and a temperature T for measuring the cooling water located in the cooling water circuit_WA first temperature sensor of (1), the cooling device being selected from the group consisting of a heat exchanger, a cooling air fan and a tap water supply device, a maximum threshold value T of cooling water in the cooling water circuit_W,maxStored in a control unit adapted to operate the pump and/or said two cooling means up to the temperature T of the cooling water_WDown to below T_W,maxWhereby the method comprises the steps of:

(b) starting a drying program;

(c) pumping cooling water through the cooling water circuit to cool and dehumidify the process air within the condenser; and

(d) cooling water in the cooling water circuit is cooled by the at least one cooling device.

In a preferred embodiment, the washer-dryer comprises a washing liquid recirculation system, wherein the pump is connected to the cooling water circuit and the washing liquid recirculation system. In a preferred method, in step (a) before step (b), the water in the drum from the rinsing step is transferred to the cooling water circuit by a pump. In this way, less or no additional water may be used for the cooling water circuit.

In another preferred embodiment, the washer-dryer further comprises a second temperature sensor arranged in the process air circuit. Preferably, the method further comprises the step of (c) measuring the temperature T of the process air_PSo as to reach a minimum threshold value T_P,minAt that time, the cooling water is started to be pumped through the cooling water circuit.

It is also preferred that the method further comprises the step of (f) measuring the temperature T of the process air_PSo as to reach the maximum threshold value T_P,maxThe pumping speed is increased and/or the cooling of the cooling water is enhanced by operating the at least one cooling device.

In another preferred embodiment, the washer-dryer further comprises a first temperature sensor arranged in the cooling water circuit. Preferably, step (d) of the method is performed by measuring the temperature T of the cooling water in the cooling water circuit_WTo change so as to reach the maximum threshold value T_W,maxBy operating the at least one cooling device, the cooling of the cooling water in the cooling water circuit is manipulated and/or enhanced up to a temperature T_WDown to below T_W,max。

Generally, how the enhancement of the operation of the at least one cooling device is achieved will depend on the type of cooling device applied in the cooling water circuit.

In a preferred embodiment, the at least one cooling device in the cooling water circuit is an air/water heat exchanger, wherein the cooling air is provided by a cooling air fan. Accordingly, an enhancement to the operation of the heat exchanger would be to increase the speed of the cooling fan.

In a further preferred embodiment, the at least one cooling device in the cooling water circuit is a mains water supply, wherein the operation corresponds to mixing water from the mains water supply with cooling water in the cooling water circuit. Accordingly, enhancing the operation of the mains water supply means will mean increasing the amount of water from the mains water supply to be mixed with the cooling water.

The present invention has many advantages. The fresh water consumption is significantly reduced in the present invention, as compared to the commercially available water-cooled washer-dryer, due to the implementation of the cooling water circuit. The warmed cooling water is not discarded at the outlet of the condenser. Nevertheless, an efficient cooling of the process air can be achieved by using a cooling device for the cooling water circuit. These advantages can be achieved in an embodiment in an easy manner. For example, if a washer-dryer according to an embodiment of the present invention includes a water liquid recirculation system, fresh water consumption may be even lower if a portion of the recirculation system is available for the cooling water circuit at the same time. If the washer-dryer according to a further embodiment of the present invention comprises a first temperature sensor measuring the temperature of the cooling water, the operation of the at least one cooling device may be adjusted such that the drying process may be efficiently performed with a reduced total energy consumption. If the washer-dryer according to a further embodiment of the present invention comprises a second temperature sensor measuring the temperature of the process air, the cooling of the process air may additionally be matched to each drying phase, which makes it possible to further rationalize the drying program in terms of drying speed, water consumption and energy consumption.

Drawings

The invention will be described below by referring to fig. 1 to 4 of the drawings. The figures show a washer-dryer according to four particular embodiments of the present invention. Other embodiments are possible.

Fig. 1 shows a cross-sectional view of a washer-dryer according to a first embodiment, comprising an open cooling water circuit, a washing liquid recirculation system and a mains water supply as cooling means, the operation being switchable between the open cooling water circuit and the washing liquid recirculation system,

fig. 2 shows a cross-sectional view of a washer-dryer according to a second embodiment, comprising an open cooling water circuit and a heat exchanger and a mains water supply therein as cooling means,

fig. 3 shows a cross-sectional view of a washer-dryer according to a third embodiment, comprising an open cooling water circuit and, as cooling means for the cooling water, a heat exchanger, a mains water supply and a reservoir, the reservoir being provided with fins on the outer surface,

fig. 4 shows a cross-sectional view of a washer-dryer according to a fourth embodiment, comprising a closed cooling water circuit and a heat exchanger and a mains water supply as cooling means for the cooling water.

Detailed Description

Fig. 1 shows a cross-sectional view of a washer-dryer 1 according to a first embodiment, comprising an open cooling water circuit 11, a washing liquid recirculation system 26 and a mains water supply 16 as cooling means, the operation being switchable between the open cooling water circuit 11 and the washing liquid recirculation system 26 by means of a three-way valve 25. The washer-dryer 1 shows a housing 2, a tub 8 and a drum 7, said drum 7 being mounted within the tub 8 such that the drum 7 is rotatable about a horizontal axis. Laundry to be treated (not shown in fig. 1) may be placed in the drum 7 via the door 3. The operation of the washer-dryer 1 is controlled by means of a control unit 23.

The tub 8 is connected to a pump 10, said pump 10 enabling the water liquid 9, e.g. lye, to be discharged from the tub 8. A pump 10 is connected to the cooling water circuit 11 and to a drain 13 via a three-way valve 12, so as to pump the water liquid 9 from the tub 8 into the cooling water circuit 11 via the valve 12, or into the drain 13 and out of the washer-dryer 1.

The tub 8 is also connected to the process air circuit 4, which enables process air to flow into the tub 8 and through the drum 7. A fan (process air fan) 6 is arranged in the process air circuit 4 in order to create an air flow. A heater 5 is arranged in the process air circuit 4 to heat the process air before it enters the tub 8. After passing through the tub 8 and the drum 7, the process air circuit 4 leads the process air into a condenser 17, which here is the space behind the tub 8 in the process air circuit 4.

The process air leaving the drum 7 is hot and humid. Within the condenser 17, condensation is triggered via cooling. In this non-limiting embodiment, the nozzle 15 is arranged within the condenser 17. The nozzle 15 is part of the cooling water circuit 11. Cooling water is pumped through the cooling water circuit 11 via a pump 10 and sprayed into the condenser 17 via a nozzle 15. In the condenser 17, the cooling water droplets cause the condensation of the moisture brought by the process air when it comes into contact with the laundry located inside the drum 7. The process air is thereby dehumidified and cooled. In this non-limiting embodiment, the cooling water circuit 11 is an open circuit in which the cooling water is in direct contact with the process air within the condenser 17.

At the outlet of the condenser 21, the cooling water is collected in the tub 8, from which tub 8 the cooling water can be circulated again in the cooling water circuit via the pump 10. In fig. 1, the flow direction of the cooling water is indicated by a dotted arrow, and the flow direction of the process air is indicated by a simple arrow.

The cooling water circuit 11 includes a passage to a tap water supply device 16 as a cooling device. Tap water can be mixed into the cooling water circuit 11 via a valve 14, wherein the valve 14 is controlled by a control unit 23 of the washer-dryer 1 and is opened and closed when required. Preferably, the specific point and duration of opening the valve 14 during the drying program is stored in the control unit 23.

In the embodiment shown in fig. 1, a first temperature sensor 22 is arranged in the cooling water circuit 11 and a second temperature sensor 24 is arranged in the process air circuit 4.

In this embodiment, if the temperature T of the cooling water is_WExceeding a maximum threshold value T for stored cooling water_W,maxThe control unit 23 may then be caused to open the valve 14. Likewise, of pump 10 and valve 14The operation may be controlled by the control unit 23 in response to a temperature signal of the second temperature sensor 24. I.e. if the temperature T is_TToo low, the pump 10 and valve 14 are not operated. In an embodiment, the operation of the pump 10 and the valve 14 may be adjusted to adapt the temperature T of the process air_PAnd thus to different stages in the drying program.

In line with the above description, the aqueous liquid 9 may be a washing liquid (lye), a rinsing water or a cooling water.

The washing-drying machine 1 according to the second to fourth embodiments shown in fig. 2 to 4 shows the same components as the washing-drying machine 1 of the first embodiment shown in fig. 1 to some extent. Therefore, these components will not be described below. Rather, the differences between these non-limiting embodiments and the first embodiment will be described in particular below.

Fig. 2 shows a cross-sectional view of a washer-dryer 1 according to a second embodiment, said washer-dryer 1 comprising an open cooling water circuit 11, and therein a heat exchanger 18 and a mains water supply 16 as cooling means.

The cooling water circuit 11 of the washer-dryer 1 in fig. 2 additionally comprises a heat exchanger 18 as a cooling device. In this non-limiting embodiment, the heat exchanger 18 is disposed downstream of the condenser outlet 21. The heat exchanger 18 is here an air/water heat exchanger comprising a cooling air fan (not shown here) which can be operated by a control unit 23 of the washer-dryer 1. However, the type of heat exchanger may be different. The cooling water passing through the heat exchanger 18 is cooled by cooling air supplied by a cooling air fan. The flow rate of the cooling air determines the amount of cooling and may be controlled via the rotational speed of the cooling air fan. Preferably, the specific point, duration and speed at which the cooling air fan is operated during the drying program are stored in the control unit 23.

Similar to the first embodiment shown in fig. 1, the washer-dryer of the second embodiment comprises a first temperature sensor 22 arranged in the cooling water circuit 11 and a second temperature sensor 24 arranged in the process air circuit 4. Further, in this embodiment, if the temperature of the cooling water is highDegree T_WExceeding a maximum threshold value T for stored cooling water_W,maxThe control unit 23 can then control the valve 14, in particular open the valve 14. Likewise, the operation of the pump 10 and the valve 14 may be controlled by the control unit in response to the temperature signal of the second temperature sensor 24. I.e. if the temperature T is_PToo low, the pump 10 and valve 14 are not operated. In an embodiment, their operation may be adjusted to the temperature T of the process air_PAnd thus to different stages in the drying program. In addition, the aqueous liquid 9 may be a washing liquid (lye), rinsing water or cooling water.

Fig. 3 shows a cross-sectional view of a washer-dryer 1 according to a third embodiment, said washer-dryer 1 comprising an open cooling water circuit 11, as well as a heat exchanger 18 as cooling means for the cooling water, a mains water supply 16 and a reservoir 19, said reservoir 19 being provided with fins 20 on its outer surface.

The cooling water circuit 11 of the washer-dryer 1 shown in fig. 3 thus additionally comprises a reservoir 19 arranged downstream of the heat exchanger 18. In order to improve the natural cooling of the cooling water passing through the walls of the reservoir 19, a surface of the reservoir 19 comprises fins 20, said surface being close to the outer wall of the casing 2 of the washer-dryer 1. These fins 20 serve to increase the surface area of the reservoir 19 and to direct the flow direction of the air over the surface of the reservoir 19, thereby enhancing the cooling effect.

The reservoir 19 serves in particular as a cooling water reservoir in the cooling water circuit 11, so that the overall volume of the cooling water circuit 11 is increased. Thus, the cooling water has already cooled naturally in the reservoir 19, thereby reducing the rate of temperature rise of the cooling water as it passes through the condenser 17. This may help to reduce the overall energy consumption of the drying process, as the other cooling means 16, 18 may be applied at a later stage.

Fig. 4 shows a sectional view of a washer-dryer 1 according to a fourth embodiment, said cooling water circuit 11 comprising a closed cooling water circuit 28, as well as a heat exchanger 18 and a mains water supply 16 as cooling means for the cooling water.

In the fourth embodiment, the cooling water is not in direct contact with the process air in the process air circuit 4. Accordingly, the cooling water is not collected in the condenser outlet 21 and is not circulated by the first pump 10. Instead, the cooling water circuit pump 27 is arranged as a second pump in the cooling water circuit 28.

In fig. 4, the recirculation system 26 for the washing liquid is only partially shown. In particular, this shows: the mains water supply 16 may be connected to a recirculation system 26 and a closed cooling water circuit 28. Accordingly, fig. 4 shows how tap water may be introduced into the tub 8.

List of reference numerals

1 washing-drying machine

2 casing

3 door

4 process air circuit

5 Heater

6 Fan

7 roller

8 barrel

9, water solution; e.g. washing or cooling water

10 pumps, first pump

11 open cooling water circuit (dotted arrow indicates flow direction)

12 valve in discharge device

13 draining device (for washing liquid, condensed water)

14 valve for water supply

15 spray nozzle

16 tap water supply device

17 condenser

18 heat exchanger in cooling water circuit

19 reservoir

20 heat sink

21 outlet of condenser

22 a cooling circuit temperature sensor; first temperature sensor

23 control unit

Process air circuit temperature sensor 24; second temperature sensor

25 three-way valve (for switching between recirculation circuit and cooling water circuit)

26 (washing liquid, water liquid) recirculation loop

27 pump, second pump, cooling circuit pump in cooling water circuit

28 closed cooling water circuit

Claims

1. A washing-drying machine (1) comprising a tub (8), a drum (7) rotatably mounted in the tub (8), a process air circuit (4) comprising a fan (6) and a heater (5) adapted to circulate process air through the drum (7) for drying laundry, a cooling water circuit (11, 28) in contact with the process air circuit (4), a pump, a condenser (17), a control unit (23), two cooling devices in heat exchange contact with the cooling water circuit (11, 28) and a temperature T for measuring cooling water located in the cooling water circuit (11, 28)_WIs a first temperature sensor (22), the cooling means being an air/water heat exchanger (18) supplied with cooling air by a cooling air fan and a mains water supply (16), wherein a maximum threshold value T for the cooling water in the cooling water circuit (11, 28)_W,maxIs stored in a control unit (23), wherein the control unit (23) is adapted to: operating the pumps (10, 27) and/or the two cooling devices until the temperature T of the cooling water_WDown to below T_W,maxWherein the cooling water circuit (11, 28) further comprises a water supply valve (14), the water supply valve (14) being capable of connecting the cooling water circuit (11, 28) with a mains water supply (16), and the water supply valve (14) being controlled by a control unit (23), wherein the washer-dryer (1) comprises a washing liquid recirculation system (26), a pump being connected to the cooling water circuit and to the washing liquid recirculation system (26) such that the pump is operable by the control unit to circulate water liquid in the cooling water circuit or in the washing liquid recirculation system (26), wherein the cooling water circuit (11, 28) comprises a reservoir (19).

2. A washer-dryer (1) as in claim 1, characterized by a reservoir (19) comprising fins (20) on the outer surface of the reservoir.

3. A washer-dryer (1) as in claim 1 or 2, characterized by a reservoir (19) comprising an inlet at the top for warmed cooling water, so that natural convection cooling can drive or assist the circulation of cooling water in the flow direction from the inlet of the reservoir (19).

4. Washing-drying machine (1) according to claim 1, characterized in that the temperature T of the cooling water_WThe relation with the flow rate of the pump (10, 27) and/or the cooling capacity of the cooling device is stored in the control unit (23), and the control unit (23) is adapted to: based on the relation, the flow rate of the pump (10, 27) and/or the cooling capacity of the cooling device is controlled.

5. A washer-dryer (1) as in any one of claims 1-2, 4, characterized by the washer-dryer (1) that includes a second temperature sensor (24) arranged in the process air circuit (4) to measure the temperature T of the process air_PThe control unit (23) is adapted to being at a temperature T_PReach the set minimum threshold value T_P,minWhen operating the pump (10, 27) and/or the cooling device in the cooling water circuit (11, 28).

6. A washer-dryer (1) as in any one of claims 1-2, 4, characterized by a cooling water circuit (11, 28) that is a closed cooling circuit, wherein the cooling water is not in direct contact with the process air in a condenser (17) located in the process air circuit (4).

7. A washer-dryer (1) as in claim 6, characterized by the pump comprising a cooling circuit pump provided in a closed cooling water circuit.

8. A washer-dryer (1) as in any one of claims 1-2, 4, characterized by a cooling water circuit that is an open cooling water circuit, wherein the cooling water circuit comprises nozzles (15) that are arranged inside the condenser (17) and that enable direct contact between the cooling water and the process air in the condenser (17) in the process air circuit (4).

9. Method for operating a washer-dryer (1) according to any one of claims 1-8 comprising a tub (8), a drum (7) rotatably mounted in the tub (8), a process air circuit (4) comprising a fan (6) and a heater (5) adapted to circulate process air through the drum (7) for drying laundry, a cooling water circuit (11, 28) in contact with the process air circuit (4), a pump (10, 27), a condenser (17), a control unit (23), two cooling devices in heat exchanging contact with the cooling water circuit (11, 28) and a temperature T for measuring cooling water located in the cooling water circuit (11, 28)_WIs a first temperature sensor (22), the cooling means being an air/water heat exchanger (18) supplied with cooling air by a cooling air fan and a mains water supply (16), wherein a maximum threshold value T for the cooling water in the cooling water circuit (11, 28)_W,maxStored in a control unit (23), wherein the control unit (23) is adapted to operating the pumps (10, 27) and/or the two cooling devices until the temperature T of the cooling water_WDown to below T_W,maxWherein the cooling water circuit (11, 28) further comprises a water supply valve (14), the water supply valve (14) being capable of connecting the cooling water circuit (11, 28) with a mains water supply (16), and the water supply valve (14) being controlled by a control unit (23), wherein the washer-dryer (1) comprises a washing liquid recirculation system (26), a pump being connected to the cooling water circuit and to the washing liquid recirculation system (26) such that the pump is operable by the control unit to circulate water liquid in the cooling water circuit or in the washing liquid recirculation system (26), wherein the cooling water circuit (11, 28) comprises a reservoir (19), characterized in that the method comprises the steps of:

(b) starting a drying program;

(c) pumping cooling water through a cooling water circuit (11, 28) to cool and dehumidify process air located within the condenser (17); and

(d) the cooling water in the cooling water circuit is cooled by two cooling devices.

10. A method according to claim 9, characterized in that in step (a) before step (b), the water liquid in the drum (7) from the rinsing step is transferred by means of a pump into a cooling water circuit.