EP4616778A1

EP4616778A1 - Dishwasher and control method therefor

Info

Publication number: EP4616778A1
Application number: EP23912731.9A
Authority: EP
Inventors: Jeong In Kim; Hyung Man Park; Jeongkon KIM; Min Jae Jeong; Jungwon Kim
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2022-12-26
Filing date: 2023-12-19
Publication date: 2025-09-17
Also published as: KR20240103091A; EP4616778A4; WO2024144056A1

Abstract

The present invention relates to a dishwasher and a control method therefor, the dishwasher exhausting, to the outside, air that has dried objects to be washed during a drying mode, including a heat pump device with merely two heat exchangers and a single switching valve so as to have a simplified dishwasher provision structure and improve space utilization, and recovering, during the drying mode, through the heat exchangers acting as an evaporator, thermal energy of washing water without draining the washing water heated during a washing mode so as to improve the energy efficiency of the heat pump device.

Description

[Technical Field]

The present disclosure relates to a dishwasher and a control method thereof, wherein air which has dried a washing target during a drying mode is discharged out, and a heat pump apparatus is configured to have only two heat-exchangers and one switching valve, thereby simplifying an installation structure of the dishwasher and improving space utilization thereof, and washing water heated during the washing mode is not drained out of a sump but the thermal energy of the heated washing water is recovered using a heat-exchanger acting as an evaporator during the drying mode, thereby improving energy efficiency of the heat pump apparatus.

[Background Art]

A dishwasher is an apparatus that washes dishes and cooking utensils as washing targets stored therein by spraying washing water thereto. In this regard, the washing water may contain washing detergent.
A dishwasher generally includes a tub having a washing space defined therein, a dish rack that accommodates therein a washing target inside the tub, a spraying arm that sprays the washing water into the dish rack, and a sump that stores therein water and supplies the washing water to the spraying arm.
Using this dishwasher may allow a time and effort required to wash the dishes and other washing targets after a meal to be reduced, thereby contributing to user convenience.
In the washing process using the dishwasher, the washing water and air may be heated and used to increase the washing effect. An electric heater may be used as a device for heating the washing water and air. In one example, the washing water may be heated using a heat pump apparatus instead of the electric heater.
The heat pump apparatus has higher energy efficiency than the electric heater. Thus, when the washing water is heated by the heat pump apparatus, the consumption of electricity may be reduced.
In this regard, European Patent No. 3082554 (Prior Document 001) discloses a dishwasher including a heat pump apparatus for heating washing water and heating air, the heat pump apparatus including two switching valves for switching refrigerant flow paths between three heat-exchangers from each other and two switching dampers for switching air flow paths from each other in order to implement an air circulation type drying path structure for drying the washing target.
However, the structure disclosed in the prior document 001 is configured to change the flow direction of the refrigerant using a plurality of pipes and the two switching valves connecting the three heat-exchangers to each other, and thus the pipe connection structure of the refrigerant is very complicated and the plurality of pipes and the two switching valves are provided, thereby deteriorating the space utilization of the dishwasher and rapidly increasing a manufacturing cost thereof.
In addition, in the structure disclosed in the prior document 001, the washing water heated during the washing mode is entirely or substantially entirely drained after the washing mode has been completed or before the drying mode is performed, such that the energy consumed for heating the washing water during the washing mode cannot be recovered, and thus the energy efficiency of the heat pump apparatus may be deteriorated.

[Disclosure]

[Technical Problem]

The present disclosure has been devised to solve the above-described problems of the prior art. Thus, a first purpose of the present disclosure is to provide a dishwasher and a control method thereof, wherein air which has dried a washing target during a drying mode is discharged to the outside, and a heat pump apparatus is configured to have only two heat-exchangers and one switching valve, thereby simplifying an installation structure of the dishwasher and improving space utilization thereof.
In addition, a second purpose of the present disclosure is to provide a dishwasher and a control method thereof, wherein washing water heated during the washing mode is not drained out of a sump but the thermal energy of the heated washing water is recovered using a heat-exchanger acting as an evaporator during the drying mode, thereby improving energy efficiency of the heat pump apparatus.
Purposes of the present disclosure are not limited to the above-mentioned purpose. Other purposes and advantages of the present disclosure that are not mentioned may be understood based on following descriptions, and may be more clearly understood based on embodiments of the present disclosure. Further, it will be easily understood that the purposes and advantages of the present disclosure may be realized using means shown in the claims and combinations thereof.

[Technical Solution]

A dishwasher according to the present disclosure includes: a tub having a washing space defined therein, wherein dishes are received in the washing space; a heat pump apparatus including: a compressor for compressing refrigerant; a first heat-exchanger configured to: receive the refrigerant having flowed through the compressor and heat the washing water to be supplied to the tub in a washing mode of the dishwasher; and receive heat from the washing water and evaporate the refrigerant to be supplied to the compressor using the heat in a drying mode of the dishwasher; and a second heat-exchanger configured to receive the refrigerant having flowed through the compressor and evaporate air to be supplied to the tub in the drying mode; a sump for storing therein the washing water heated by the first heat-exchanger; and a controller configured to determine whether to drain the washing water stored in the sump in the drying mode of the dishwasher, wherein the controller may be further configured to: circulate the washing water between the sump and the first heat-exchanger to exchange heat between the first heat-exchanger and the refrigerant in the drying mode; and determine whether to drain the washing water stored in the sump, based on a difference value between a temperature of the washing water and a temperature of the air heated by the second heat-exchanger, in the drying mode.
Furthermore, the determining of whether to drain the washing water may include: calculating a difference value between the temperature of the washing water and the temperature of the heated air, and comparing the calculated difference value with a predetermined threshold value; and upon determination based on the comparing result that the calculated difference value may be greater than or equal to the predetermined threshold value, determining to drain a portion of the washing water.
Furthermore, the dishwasher may further comprise: a first temperature sensor configured to sense the temperature of washing water in the drying mode; and a second temperature sensor configured to sense the temperature of the air heated by the second heat-exchanger in the drying mode, wherein the determining of whether to drain the washing water may include: receiving output signals from the first temperature sensor and the second temperature sensor, respectively; and detecting the temperature of the washing water and the temperature of the heated air, based on the output signal of the first temperature sensor and the output signal of the second temperature sensor, respectively.
Furthermore, the predetermined threshold value may be in a range of 8°C to 12°C.
Furthermore, the dishwasher may further comprise: a water discharge pump configured to discharge the washing water stored in the sump to the outside; and a timer for measuring an operation time of the water discharge pump, wherein the draining of the portion of the washing water may include: supplying power to the water discharge pump to start an operation of the water discharge pump; measuring, using the timer, an elapsed time duration after the operation of the water discharge pump may be started; comparing the elapsed time duration with a predetermined set time duration; and upon determination that the measured elapsed time duration may be greater than or equal to the predetermined set time duration, cutting off the power supply to the water discharge pump and stopping the operation of the water discharge pump.
Furthermore, the predetermined set time duration may be in a range of 30 seconds to 60 seconds.
Furthermore, the dishwasher may further comprise a pump connected to each of the sump and the first heat-exchanger and configured to circulate the washing water between the sump and the first heat-exchanger, wherein the exchanging of the heat between the first heat-exchanger and the refrigerant in the drying mode may include: supplying power to the pump to start an operation of the pump; and maintaining the operation of the pump in an operation mode different from an operation mode of the pump in the washing mode.
Furthermore, the operation mode different from the operation mode of the pump in the washing mode may include: a mode in which the pump operates at a rotation speed lower than a rotation speed in the washing mode; or a mode in which an operation-a stop of the pump may be repeated at a predetermined period.
Furthermore, the lower rotation speed may be in a range of 800 RPM to 1000 RPM.
Furthermore, the predetermined period may be in a range of 5 to 10 seconds.
A method for controlling a dishwasher according to the present disclosure is provided. The dishwasher includes: a tub having a washing space defined therein, wherein dishes are received in the washing space; a heat pump apparatus including: a compressor for compressing refrigerant; a first heat-exchanger configured to: receive the refrigerant having flowed through the compressor and heat the washing water to be supplied to the tub in a washing mode of the dishwasher; and receive heat from the washing water and evaporate the refrigerant to be supplied to the compressor using the heat in a drying mode of the dishwasher; and a second heat-exchanger configured to receive the refrigerant having flowed through the compressor and evaporate air to be supplied to the tub in the drying mode; and a sump for storing therein the washing water heated by the first heat-exchanger. The method comprises: circulating the washing water between the sump and the first heat-exchanger to exchange heat between the first heat-exchanger and the refrigerant, in the drying mode; and determining whether to drain the washing water stored in the sump, based on a difference value between a temperature of the washing water and a temperature of the air heated by the second heat-exchanger, in the drying mode.
Furthermore, the determining of whether to drain the washing water may include: calculating a difference value between the temperature of the washing water and the temperature of the heated air, and comparing the calculated difference value with a predetermined threshold value; and upon determination based on the comparing result that the calculated difference value may be greater than or equal to the predetermined threshold value, determining to drain a portion of the washing water.
Furthermore, the determining of whether to drain the washing water may include: receiving output signals from a first temperature sensor and a second temperature sensor, respectively, wherein the first temperature sensor may be configured to sense the temperature of washing water in the drying mode, and the second temperature sensor may be configured to sense the temperature of the air heated by the second heat-exchanger in the drying mode; and detecting the temperature of the washing water and the temperature of the heated air, based on the output signal of the first temperature sensor and the output signal of the second temperature sensor, respectively.
Furthermore, the predetermined threshold value may be in a range of 8°C to 12°C.
Furthermore, the draining of the portion of the washing water may include: supplying power to a water discharge pump to start an operation of the water discharge pump, wherein the water discharge pump may be configured to discharge the washing water stored in the sump to the outside; measuring, using a timer, an elapsed time duration after the operation of the water discharge pump may be started; comparing the elapsed time duration with a predetermined set time duration; and upon determination that the measured elapsed time duration may be greater than or equal to the predetermined set time duration, cutting off the power supply to the water discharge pump and stopping the operation of the water discharge pump.
Furthermore, the predetermined set time duration may be in a range of 30 seconds to 60 seconds.
Furthermore, the exchanging of the heat between the first heat-exchanger and the refrigerant in the drying mode may include: supplying power to the pump to start an operation of the pump, wherein the pump may be connected to each of the sump and the first heat-exchanger and may be configured to circulate the washing water between the sump and the first heat-exchanger; and maintaining the operation of the pump in an operation mode different from an operation mode of the pump in the washing mode.
Furthermore, the operation mode different from the operation mode of the pump in the washing mode may include: a mode in which the pump operates at a rotation speed lower than a rotation speed in the washing mode; or a mode in which an operation-a stop of the pump may be repeated at a predetermined period.
Furthermore, the lower rotation speed may be in a range of 800 RPM to 1000 RPM.
Furthermore, the predetermined period may be in a range of 5 to 10 seconds.

[Advantageous Effects]

In the dishwasher and the control method thereof in accordance with the present disclosure, the air which has dried a washing target during a drying mode is discharged to the outside, and the heat pump apparatus is configured to have only two heat-exchangers and one switching valve, thereby simplifying an installation structure of the dishwasher and improving space utilization thereof.
In addition, in the dishwasher and the control method thereof in accordance with the present disclosure, the washing water heated during the washing mode is not drained out but the thermal energy of the heated washing water is recovered using the heat-exchanger acting as an evaporator during the drying mode, thereby improving energy efficiency of the heat pump apparatus.
In addition to the above-mentioned effects, the specific effects of the present disclosure as not mentioned will be described below along with the descriptions of the specific details for carrying out the present disclosure.

[Description of Drawings]

FIG. 1 is a front perspective view of a dishwasher according to an embodiment of the present disclosure.
FIG. 2 is a schematic cross-sectional view of the dishwasher illustrated in FIG. 1.
FIG. 3 is a schematic view for illustrating a heat pump apparatus provided in the dishwasher of FIG. 2.
FIG. 4 is a schematic view of a dishwasher having a heat pump apparatus according to an embodiment of the present disclosure.
FIG. 5 is a partially enlarged view of FIG. 4.
FIG. 6 is a schematic view for illustrating an operation of the heat pump apparatus when the dishwasher illustrated in FIG. 4 operates in a washing mode.
FIG. 7 is a schematic view for illustrating an operation of the heat pump apparatus when the dishwasher illustrated in FIG. 4 operates in a drying mode.
FIG. 8 is a functional block diagram illustrating a configuration of a controller of a dishwasher according to an embodiment of the present disclosure.
FIGS. 9 to 11 are flowcharts for illustrating a control step performed by the controller illustrated in FIG. 8.

[Best Mode]

The above-mentioned purposes, features, and advantages will be described in detail later with reference to the attached drawings, so that those skilled in the art in the technical field to which the present disclosure belongs may easily implement the technical ideas of the present disclosure. In describing the present disclosure, upon determination that a detailed description of the publicly known technology related to the present disclosure may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Hereinafter, a preferred embodiment according to the present disclosure will be described in detail with reference to the attached drawings. In the drawings, identical reference numerals are used to indicate identical or similar components.
Although first, second, and the like are used to describe various components, these components are not limited by such terms. Such terms are only used to distinguish one component from another component, and unless specifically stated to the contrary, a first component may also be a second component.
Throughout the present document, unless otherwise stated, each component may be singular or plural.
Hereinafter, a first component being disposed "on top of (or under)" a second component may mean that the first component may be disposed in contact with a top surface (or a bottom surface) of the second component, as well as a third component may be interposed between the second component and the first component disposed "on top of (or under)" the second component.
Furthermore, when a first component is described as being "connected" or "coupled" to a second component, the components may be directly connected or coupled to each other, but a third component may be "interposed" between the components or the components may be "connected" or "coupled" to each other via the third components.
As used herein, the singular constitutes "a" and "an" are intended to include the plural constitutes as well, unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "include" should not be construed as necessarily including all of various components or operations described herein, but should be construed that some components or operations among those may not be included or additional components or operations may be further included.
As used herein, the singular constitutes "a" and "an" are intended to include the plural constitutes as well, unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "include" should not be construed as necessarily including all of various components or operations described herein, but should be construed that some components or operations among those may not be included or additional components or operations may be further included.
Throughout the present document, "A and/or B" means A, B, or A and B, unless otherwise specified, and "C to D" means equal to or greater than C and equal to or smaller than D unless otherwise specified.

[Overall structure of dishwasher]

Hereinafter, an overall structure of a dishwasher 1 according to an embodiment of the present disclosure will be described in detail with reference to the attached drawings.
FIG. 1 is a front perspective view showing the dishwasher according to the present disclosure. FIG. 2 is a simplified cross-sectional view briefly showing an internal structure of the dishwasher according to the present disclosure.
As illustrated in FIG. 1 to FIG. 2, the dishwasher 1 according to an embodiment of the present disclosure may include a casing 9 that constitutes an exterior appearance, a tub 2 installed in an inner space of the casing 9 and having a washing space 21 defined therein where the washing target is washed, wherein a front surface of the tub is open, a door 3 that opens/closes the open front surface of the tub 2, a sump 4 disposed under the tub 2 for storing therein the washing water for washing the washing target, a dish rack 5 removably provided in the inner washing space 21 of the tub 2 to receive therein the washing target, and a water sprayer 20 installed adjacent to the dish rack 5 to spray the washing water for washing the washing target thereto.
In this regard, the washing target received in the dish rack 5 may be, for example, dishes such as bowls, plates, spoons, and chopsticks, and other cooking utensils. Hereinafter, unless otherwise specified, the washing target will be referred to as a dish.
The tub 2 may be formed in a box shape with an entirely open front surface, and have a configuration of a so-called washing tub.
The washing space 21 may be defined inside the tub 2. The open front surface of the tub 2 may be opened/closing by the door 3.
The tub 2 may be formed via pressing of a metal plate resistant to high temperature and moisture, for example, a stainless steel plate.
Moreover, on an inner surface of the tub 2, a plurality of brackets may be disposed for the purpose of supporting and installing functional components such as the dish rack 5 and the water sprayer 20 which will be described later thereon within the tub 2.
In one example, the sump 4 may include storage 41 that stores therein washing water, a sump cover 42 that distinguishes the storage 41 from the tub 2, a water supply 43 that supplies washing water from an external source to the storage 41, a water discharger 44 that discharges the washing water of the storage 41 to an outside, and a washing pump 45 and a supply flow path 46 that supply the washing water of the storage 41 to the water sprayer 20.
The sump cover 42 may be disposed at a top of the sump 4 and may serve to distinguish the tub 2 and the sump 4 from each other. Moreover, the sump cover 42 may have a plurality of collecting holes defined therein for collecting washing water sprayed into the washing space 21 through the water sprayer 20 into the sump 4.
That is, the washing water sprayed from the water sprayer 20 toward the dish may fall down to a bottom of the washing space 21, and may be collected again through the sump cover 42 and into the storage 41.
The washing pump 45 may be disposed at a side or a bottom of the sump 4 and may serve to pressurize the washing water and supply the pressurized washing water to the water sprayer 20.
One end of the washing pump 45 may be connected to the storage 41 of the sump 4 and the other end thereof may be connected to the supply flow path 46. The washing pump 45 may be equipped with an impeller 451 and a motor 453. When power is supplied to the motor 453, the impeller 451 may rotate, and thus the washing water in the storage 41 may be pressurized, and then may be supplied to the water sprayer 20 through the supply flow path 46.
In one example, the supply flow path 46 may serve to selectively supply the washing water supplied from the washing pump 45 to the water sprayer 20.
For example, the supply flow path 46 may include a first supply flow path 461 connected to a lower spraying arm 26, and a second supply flow path 463 and 467 connected to an upper spraying arm 27 and a top nozzle 29. The supply flow path 46 may be provided with a supply flow path switching valve 465 that selectively opens/closes the supply flow paths 461, 463 and 467.
In this regard, the supply flow path switching valve 465 may be controlled so that the supply flow paths 461, 463 and 467 are opened sequentially or simultaneously.
The water discharger 44 serves to discharge the washing water stored in the storage 41 to the outside. More specifically, the water discharger 44 may include a drainage pipe 441 connected to the storage 41 and constructed to guide the washing water of the storage 41 to the outside, and a water discharge pump 442 connected to the drainage pipe 441 and configured to pressurize and discharge the washing water. After the washing cycle has been completed and after the rinsing cycle has been completed, the water discharge pump 442 operates such that the washing water supplied to perform the washing cycle and the rinsing cycle may be discharged from the storage 41 to the outside along the drainage pipe 441.
In one example, the water sprayer 20 may be constructed to spray the washing water to the dishes stored in the dish rack 5.
More specifically, the water sprayer 20 may include the lower spraying arm 26 located under the tub 2 to spray the washing water to a lower rack 51, the upper spraying arm 27 located between the lower rack 51 and an upper rack 53 to spray the washing water to the lower rack 51 and the upper rack 53, and the top nozzle 29 located on top of the tub 2 to spray the washing water to a top rack or the upper rack 53.
In particular, the lower spraying arm 26 and the upper spraying arm 27 may be rotatably disposed in the washing space 21 of the tub 2 and may spray the washing water toward the washing target of the dish rack 5 while being rotating.
The lower spraying arm 26 may be rotatably supported on a top of the sump cover 42 so as to spray the washing water toward the lower rack 51 while being rotating and being disposed under the lower rack 51.
Moreover, the upper spraying arm 27 may be rotatably supported so as to spray the washing water on the dish while being rotating and being disposed between the lower rack 51 and the upper rack 53.
In one example, in order to increase washing efficiency, additional means for diverting the washing water sprayed from the lower spraying arm 26 into an upward direction (diverting in a U-direction) may be provided at a lower surface 25 of the tub 2.
In one example, the dish rack 5 for storing the washing target therein may be disposed in the washing space 21.
The dish rack 5 may be constructed to extend or retract from or into the inner space of the tub 2 through the open front surface of the tub 2.
For example, in FIG. 2, an embodiment is shown in which the dish rack 5 includes the lower rack 51 located at a lower portion of the tub 2 to accommodate therein relatively large dishes, the upper rack 5 located on top of the lower rack 51 to accommodate therein medium-sized dishes, and the top rack located at a top level of the tub 2 and capable of storing therein small dishes, etc. However, the present disclosure is not limited thereto. However, hereinafter, an example in which the dishwasher includes the three dish racks 5 as shown is described.
Each of the lower rack 51, the upper rack 53, and the top rack may be constructed to extend or retract from or into the inner space of the tub 2 through the open front surface of the tub 2.
For this purpose, guide rails (not shown) may be respectively disposed on both opposing walls constituting an inner surface of the tub 2. By way of example, the guide rails (not shown) may include an upper rail, a lower rail, and a top rail.
Wheels may be disposed on a bottom of each of the lower rack 51, the upper rack 53, and the top rack. The user may extend the lower rack 51, the upper rack 53, and the top rack from the inner space of the tub 2 through the open front surface of the tub 2 and may place the washing target thereon, or easily withdraw the washing target that have been washed out thereof.
The guide rail (not shown) may be embodied as a simple rail-type fixed guide rail to guide the extending or the retracting of the rack 5, or a telescopic guide rail capable of guiding the extending or the retracting of the rack 5 and at the same time, increasing an extension distance thereof as the rack 5 further extends from the inner space of the tub.
In one example, the door 3 is configured for opening/closing the open front surface of the tub 2 as described above.
A hinge (not shown) around which the door 3 is closed or opened may be provided at a bottom of the open front surface. Thus, the door 3 may pivot around the hinge as a pivot axis.
In this regard, a handle 3a for opening the door 3 and a control panel 3b for controlling the dishwasher 1 may be disposed on an outer side surface of the door 3.
As shown, the control panel 3b may include a display 3c that visually displays information regarding a current operating status of the dishwasher, etc., and a button unit 3d including a selection button through which a user's selection manipulation is input and a power button through which a user's manipulation for turning the dishwasher on and off is input.
In one example, a rear panel constituting an inner side surface of the door 3 may constitute one side surface of the tub 2 when the door 3 has been closed, and may constitute a seat surface on which the lower rack 51 of the dish rack 5 is supported when the door 3 is fully opened.
For this purpose, when the door 3 is fully opened downwardly, the rear panel of the door 3 may constitute a horizontal plane extending in the same direction as a direction in which the guide rail (not shown) guiding the displacement of the lower rack 51 extends.
In one example, the dishwasher 1 according to an embodiment of the present disclosure may further include a base 8.
The base 8 may be disposed under the tub 2 and may serve to support the tub 2.
Alternatively, the base 8 may provide a space in which the sump 4 is accommodated, and may provide an accommodation space in which various devices provided in the dishwasher 1 are accommodated.
Therefore, the base 8 may be manufactured to have an outer wall to support an entirety of the dishwasher, and to have an outer wall defining an accommodation space in which various devices are accommodated.
In one example, in the dishwasher according to an embodiment of the present disclosure, the washing water to be supplied to the tub 2 is heated and thus, the high-temperature washing water is sprayed to the washing target accommodated in the tub 2, thereby improving washing efficiency of the washing target and performance of the dishwasher 1.
To this end, the dishwasher according to an embodiment of the present disclosure may include a heat pump apparatus 10 for heating the washing water introduced into the tub 2. The heat pump apparatus 10 may heat the washing water so that the dishes are washed with high-temperature washing water, thereby improving the performance of the dishwasher.
The device for heating the washing water may be generally embodied as an electric heater that heats the washing water by converting electrical energy into thermal energy.
A coefficient of performance (COP) is a measure indicating the energy efficiency of each of the electric heater and the heat pump apparatus 10. As the coefficient of performance (COP) increases, the energy efficiency of the device increases.
The electric heater has a maximum COP of merely 1. However, when the washing water is heated using the heat pump apparatus 10 instead of the electric heater, the heat pump apparatus 10 may heat the washing water by transferring the heat from a low temperature thermal reservoir to a high temperature thermal reservoir.
Due to this structure, the COP of the heat pump apparatus 10 may exceed 1.
The COP of most of the heat pump apparatuses 10 actually used exceeds 1. Therefore, in the dishwasher that heats the washing water using the heat pump apparatus 10, energy efficiency may be improved compared to that when heating the washing water using the electric heater.

[Schematic Configuration of Heat Pump Apparatus]

Hereinafter, the heat pump apparatus 10 provided in the dishwasher 1 according to an embodiment of the present disclosure will be described in more detail with reference to FIG. 3 and subsequent drawings.
FIG. 3 is a schematic diagram schematically showing the configuration of the heat pump apparatus 10.
In the drawings of FIG. 3 and subsequent drawings, a refrigerant flow path Fr is indicated by a solid line, a washing water flow path Fw is indicated by a dashed line, and an air flow path Fa is indicated by a dotted line.
Referring to FIG. 3, the heat pump apparatus 10 may include a compressor 100, a condenser 201, an expansion valve 300, and an evaporator 202.
The compressor 100, the condenser 201, the expansion valve 300, and the evaporator 202 are connected to each other via a pipe, and the pipe provides the refrigerant flow path Fr through which the refrigerant may flow.
The refrigerant may function as a working fluid that absorbs heat or releases the heat while sequentially circulating through the compressor 100, the condenser 201, the expansion valve 300, and the evaporator 202 while a phase thereof is changing from liquid to gas, or from gas to liquid.
The compressor 100 may compress the refrigerant to discharge the refrigerant in a high-temperature and high-pressure state. The refrigerant discharged from the compressor 100 may be introduced into the condenser 201.
The refrigerant may radiate heat of QH while flowing through the condenser 201. The heat emitted from the condenser 201 may be used to heat the washing water or air introduced into the tub 2. Accordingly, respective flow paths through which the refrigerant, the washing water, and the air pass, respectively may be provided in the condenser 201. The refrigerant may dissipate the heat and thus may be phase-changed from gas to a liquid state while flowing through the condenser 201.
In this regard, the refrigerant having flowed through the condenser 201 may be a mixed gas of a liquid and a gas having a very small gas content, or may be a subcooled liquid.
The refrigerant discharged from the condenser 201 may be expanded while flowing through the expansion valve 300. As a result of the expansion of the refrigerant, the temperature of the refrigerant is lowered such that the refrigerator becomes a mixed gas in which gas and liquid are mixed with each other.
The refrigerant discharged from the expansion valve 300 absorbs heat QL from the air of the tub 2 and evaporates while flowing through the evaporator 202, and accordingly, the content of the gas in the refrigerant increases.
In a state in which the refrigerant has exited the evaporator 202, the refrigerant may be a mixed gas having a very small proportion of liquid or a superheated gas.
The refrigerant discharged from the evaporator 202 may be introduced into the compressor 100 again and compressed by the compressor to become a high-temperature and high-pressure gas.
In the above-described order, the refrigerant circulates through the heat pump apparatus 1. In this circulation process, the phase of the refrigerant changes, and accordingly, the refrigerant may absorb heat in the evaporator 202 and discharge heat in the condenser 201.
In order to allow active heat transfer in the evaporator 202, it is desirable to allow a large amount of air to flow toward the evaporator 202. To this end, the heat pump apparatus 10 may further include a blower fan 620 for blowing the air toward the evaporator 202.
In one example, the dishwasher 1 may operate in a washing mode in which the heated washing water is sprayed to the dishes as the washing target accommodated in the tub 2, and a drying mode in which the heated air is sprayed to the dishes accommodated in the tub 2 to remove moisture from a surface of the washing target after the washing mode is terminated. As will be described later, the washing mode in which the heated washing water is sprayed may be performed during the washing cycle or the rinsing cycle. The drying mode may be performed during the drying cycle. In particular, a process of spraying the heated washing water during the rinsing process may be defined as a heating rinsing process.
In an embodiment as described below, a plurality of heat-exchangers are provided. When the washing mode or the drying mode is performed, each heat-exchanger may be used or not used, and may act as the condenser 201 or the evaporator 202.

[Pipe Connection Structure of Heat Pump Apparatus and Tub]

Hereinafter, a connection structure between the heat pump apparatus 10 and the tub 2 via a pipe and a duct according to an embodiment of the present disclosure will be described in detail with reference to FIGS. 4 to 6.
First, referring to FIG. 4, the heat pump apparatus 10 according to an embodiment may be configured to include the compressor 100, a first heat-exchanger 210, a second heat-exchanger 220, an expansion valve 320, and a four-way valve 400a.
The first heat-exchanger 210 may act as the condenser 201 of transferring the heat from the refrigerant to the washing water so that the washing water is heated and the refrigerant is condensed during the washing mode.
In addition, as will be described later, when the drying mode is performed, the refrigerant flow path Fr is switched by the four-way valve 400a, such that the refrigerant having flowed through the second heat-exchanger 220 and the expansion valve 320 may be introduced into the first heat-exchanger 210. Accordingly, the refrigerant in the first heat-exchanger 210 absorbs heat from the washing water and evaporates during the drying mode. Thus, in the drying mode, the function of the first heat-exchanger 210 may be switched to the evaporator 202.
The expansion valve 320 may be disposed between the first heat-exchanger 210 and the second heat-exchanger 220. When the washing mode is performed, the refrigerant may be introduced from the first heat-exchanger 210 to the expansion valve 320 to expand the refrigerant. When the drying mode is in progress, the refrigerant may be introduced from the second heat-exchanger 220 to the expansion valve 320 to expand the refrigerant.
The four-way valve 400a is connected to each of the compressor 100, the first heat-exchanger 210, and the second heat-exchanger 220 via each of corresponding pipes, and performs a function of changing the refrigerant flow path Fr based on whether an operation mode is the washing mode or the drying mode.
The four-way valve 400a may allow the refrigerant flow path Fr in the washing mode and the refrigerant flow path Fr in the drying mode to be different from each other. Thus, the four-way valve 400a may allow each of the first heat-exchanger 210 and the second heat-exchanger 220 to act as the condenser 201 or as the evaporator 202 based on whether an operation mode is the washing mode or the drying mode.
In one example, the heat pump apparatus 10 according to an embodiment may further include a first pipe 410 and a fifth pipe 450 connecting the four-way valve 400a and the compressor 100 to each other, a second pipe 420 connecting the four-way valve 400a and the first heat-exchanger 210 to each other, and a fourth pipe 440 connecting the four-way valve 400a and the second heat-exchanger 220 to each other. Each pipe may provide a refrigerant flow path Fr through which the refrigerant flows and circulates.
In one example, the heat pump apparatus 10 may include a blower fan 620 disposed to face the second heat-exchanger 220 and configured to generate an airflow of air flowing through the second heat-exchanger 220.
The blower fan 620 serves to blow air so that a large amount of air flows through the second heat-exchanger 220. Accordingly, an amount of heat transfer between the refrigerant flowing inside the second heat-exchanger 220 and the air flowing outside the second heat-exchanger 220 may be improved.
In one example, the dishwasher 1 may include the sump 4 disposed under the tub 2 and constructed to store therein the washing water, the sprayer 20 disposed inside the tub 2, connected to the sump 4, and configured to spray the washing water, and the water discharger for discharging the washing water stored in the sump 4.
The first heat-exchanger 210 and the sump 4 may be connected to each other via a pipe constituting the washing water flow path Fw through which the washing water circulates. To this end, the dishwasher 1 may include a first water supply flow path 31 and a washing pump 45. The first water supply flow path 31 may be disposed in the above-described supply flow path 46.
The first water supply flow path 31 may connect the first heat-exchanger 210 and the sprayer 20 to each other, and the washing water may flow in the first water supply flow path 31. The washing pump 45 may be disposed in a circulation flow path 50 connecting the sump 4 and the first heat-exchanger 210 to each other, or may be disposed in the first water supply flow path 31. An embodiment in which the washing pump 45 is disposed in the circulation flow path 50 is described below with reference to FIG. 4. The present disclosure is not limited thereto. However, the present disclosure will be described based on the illustrated embodiment.
The circulation flow path 50 may be connected to the first heat-exchanger 210. Thus, the washing water may be heated by absorbing the heat from the refrigerant flowing through the first heat-exchanger 210 while flowing through the first heat-exchanger 210 through the circulation flow path 50. The refrigerant may be condensed while the heat therefrom is taken away by the washing water in the first heat-exchanger 210 acting as the condenser 201.
The heated washing water discharged from the first heat-exchanger 210 may be introduced into the sprayer 20 through the first water supply flow path 31 and may be sprayed to the tub 2 through the sprayer 20.
The washing water may drop downwardly from the tub 2 and re-enter the sump 4. The sump 4 may be disposed under the tub 2. Therefore, the washing water may drop downwardly of the tub 2 under the gravity and be introduced into the sump 4.
The water discharger 44 serves to discharge the washing water stored in the storage 41 to the outside. More specifically, as shown in FIG. 4 and FIG. 5, the water discharger 44 may include the drainage pipe 441 connected to the storage 41 and constructed to guide the washing water of the storage 41 to the outside, and the water discharge pump 442 connected to the drainage pipe 441 and configured to pressurize and discharge the washing water. After the washing cycle has been completed and after the rinsing cycle has been completed, the water discharge pump 442 operates such that the washing water supplied to perform the washing cycle and the rinsing cycle may be discharged from the storage 41 to the outside along the drainage pipe 441.
In one example, the heat pump apparatus 10 of the dishwasher 1 according to an embodiment may further include an air flow channel 600 that provides an air flow path Fa along which the air to be supplied to the tub 2 and the air discharged from the tub 2 flow during the drying mode.
First, as illustrated in FIG. 4, the air flow channel 600 may include a supply duct 640 defining an introduction flow path for guiding air having flowed through the blower fan 620 toward the tub 2.
The supply duct 640 may have a first inlet 641 formed at one end thereof, and a second outlet 644 formed at the other end thereof. The air introduction flow path may be formed between the first inlet 641 and the second outlet 644.
The first inlet 641 of the supply duct 640 may always communicate with a fan housing (not shown) of the blower fan 620. Accordingly, the airflow of the air having flowed through the blower fan 620 may be introduced into the supply duct 640 through the first inlet 641.
The second outlet 644 of the supply duct 640 may communicate with the tub 2. By way of example, the second outlet 644 may be formed in a lower surface of the tub 2 so that air may be effectively sprayed onto the washing target and drying efficiency for drying the washing target may be secured.
Between the first inlet 641 and the second outlet 644, a first outlet 643 opened toward the base 8 and a second inlet 642 constituting an inner flow path of the supply duct 640 may be formed.
As described above, the second heat-exchanger 220 functions as an evaporator during the washing mode and functions as a condenser during the drying mode.
The first outlet 643 serves to discharge the air cooled while flowing through the second heat-exchanger 220 toward the base 8 during the washing mode.
The second inlet 642 serves as an intermediate inlet for introducing the air heated while flowing through the second heat-exchanger 220 toward the second outlet 644 during the drying mode.
As described above, the flow path Fa of the air generated inside the supply duct 640 may be switched such that the flow path Fa of the air generated inside the supply duct 640 in the washing mode and the flow path Fa of the air generated inside the supply duct 640 in the drying mode are different from each other.
The air flow channel 600 may include a damper 632 as a means for switching the internal air flow path Fa of the supply duct 640.
The first outlet 643 and the second inlet 642 may be selectively opened and closed by the damper 632.
In this regard, the selective opening and closing may mean that one of the two opening and closing targets is opened and one thereof is closed.
Accordingly, the damper 632 selectively opening and closing the first outlet 643 and the second inlet 642 of the supply duct 640 may be interpreted as that the second inlet 642 is closed when the first outlet 643 is opened, and the formulation second inlet 642 is opened when the first outlet 643 is closed.
Accordingly, during the drying mode, when the first outlet 643 is closed by the damper 632, the air discharged from the blower fan 620 may be introduced into the second inlet 642 of the supply duct 640, and may flow along the air flow path Fa formed inside the supply duct 640, flow through the second outlet 644 of the supply duct 640, and then be introduced into the tub 2.
However, as will be described later, when the washing mode is performed, the second inlet 642 of the supply duct 640 may be blocked by the damper 632, and the first outlet 643 may be opened by the damper 632.
In order to easily perform such selective opening and closing, the damper 632 may be embodied as a flap-type damper that is pivotable about one end thereof as shown in FIG. 4.
However, this is merely an example, and any means capable of implementing the selective opening and closing may be applied as the damper 632 without limitation thereto.

[Refrigerant and Air Flow Paths in Washing Mode]

Hereinafter, the operation of the heat pump apparatus 10 when washing water is heated during the washing mode according to an embodiment of the present disclosure will be described with reference to FIG. 6. The washing mode may be performed during a process of heating and spraying the washing water. The washing mode may be performed, for example, during a portion of the washing process or during the heating rinsing process.
When the heat pump apparatus 10 of the dishwasher 1 operates in the washing mode, the four-way valve 400a may connect the first pipe 410 and the second pipe 420 to each other and may also connect the fourth pipe 440 and the fifth pipe 450 to each other.
In this case, the first pipe 410 is not connected to the fourth pipe 440 or the fifth pipe 450, and the second pipe 420 is not connected to the fourth pipe 440 or the fifth pipe 450.
Accordingly, the first pipe 410 and the second pipe 420 may be separated from the fourth pipe 440 and the fifth pipe 450, and similarly, the fourth pipe 440 and the fifth pipe 450 may be separated from the first pipe 410 and the second pipe 420.
Accordingly, the refrigerant flow path Fr along which the refrigerant flowing out from the compressor 100 flows through the first pipe 410 and the second pipe 420 and flows into the first heat-exchanger 210, and the refrigerant flowing out from the second heat-exchanger 220 sequentially flows through the fourth pipe 440 and the fifth pipe 450 and flows into the compressor 100 may be established.
In this case, since the refrigerant flowing into the first heat-exchanger 210 is in a high-temperature/high-pressure state, the heat from the refrigerant may be taken away by the washing water flowing through the first heat-exchanger 210 such that the refrigerant may be condensed. Accordingly, the first heat-exchanger 210 may operate as a condenser that heats the washing water.
The refrigerant flowing out of the first heat-exchanger 210 may be expanded while flowing through the expansion valve 320 such that the temperature of the refrigerant is lowered.
The refrigerant discharged from the expansion valve 320 may sequentially flow through the second heat-exchanger 220, the fourth pipe 440, the four-way valve 400a, and the fifth pipe 450 and may be introduced into the compressor 100.
In this regard, the refrigerant introduced into the second heat-exchanger 220 absorbs the heat from the air and evaporates while flowing through the second heat-exchanger 220. Thus, the second heat-exchanger 220 acts as an evaporator.
On the other hand, when the washing mode is performed, the damper 632 pivots to a position at which the damper closes the second inlet 642 as described above.
Accordingly, the air flow path Fa inside the supply duct 640 may be closed, and the inflow and outflow of air to and from the tub 2 may be blocked.
In this case, the first outlet 643 of the supply duct 650 is opened toward the base 8.
Accordingly, when the blower fan 620 operates, the air of the base 8 may be converted to the airflow which flows by the second heat-exchanger 220 such that heat-exchange between the air and the refrigerant may occur. The air having flowed by the second heat-exchanger 220 may be introduced into the fan housing and then discharged toward the base 8 through the first outlet 643 of the supply duct 640.

[Refrigerant and Air Flow Paths in Drying Mode]

Next, the operation of the heat pump apparatus 10 in the case in which the heat pump apparatus 10 of the dishwasher 1 condenses water vapor included in the air and heats the air during the drying mode according to an embodiment of the present disclosure will be described with reference to FIG. 7.
The heat pump apparatus 10 of the dishwasher 1 may operate in the drying mode in which the washing target accommodated in the tub 2 is dried using heated air after the washing mode is terminated. The drying mode may be performed during the drying process.
When the drying mode is in progress, the flow of washing water in the heat pump apparatus 10 may continue without stopping.
However, when the drying mode is performed, the washing water is not sprayed to the tub 2, while the circulation of the washing water may be maintained.
That is, based on an embodiment shown in FIG. 7, the washing pump 45 may operate so that the circulation of washing water between the first heat-exchanger 210 and the sump 4 is maintained. In this case, the washing pump 45 may operate in an operation mode different from the operation mode when the washing mode is progressed. By way of example, the washing pump 45 may operate in a lower rotation speed mode having a speed lower than that in when the washing cycle or the rinsing cycle is performed, or may operate in a mode in which the operation-stop is repeated at a predetermined period. Accordingly, the thermal energy of the washing water heated during the washing mode may be recovered again via the first heat-exchanger 210 whose the function has been converted into the evaporator.
In addition, the heated air may be injected into the tub 2 via the air flow channel 600.
When the dishwasher 1 operates in the drying mode, the four-way valve 400a may connect the first pipe 410 and the fourth pipe 440 to each other, and the second pipe 420 and the fifth pipe 450 may be separated from the first pipe 410 and the fourth pipe 440.
In this case, the first pipe 410 is not connected to the second pipe 420 or the fifth pipe 450, and the fourth pipe 440 is not connected to the second pipe 420 or the fifth pipe 450. Instead, the second pipe 420 and the fifth pipe 450 may be connected to each other.
Accordingly, the refrigerant flow path Fr along which the refrigerant flowing out from the compressor 100 flows through the first pipe 410 and the fourth pipe 440 and flows into the second heat-exchanger 220, and the refrigerant flowing out from the second heat-exchanger 220 flows into the first heat-exchanger 210 through the expansion valve 320 may be established.
More specifically, the refrigerant discharged from the compressor 100 may sequentially flow through the first pipe 410, the four-way valve 400a, and the fourth pipe 440 and may be introduced into the second heat-exchanger 220.
The high-temperature refrigerant passing through the second heat-exchanger 220 may be condensed while the heat therefrom is taken away by the air. Accordingly, the second heat-exchanger 220 may operate as the condenser 201 during the drying mode.
The refrigerant may be introduced into the expansion valve 320. The refrigerant having flowed through the expansion valve 320 may be introduced into the first heat-exchanger 210 through the sixth pipe 460.
The refrigerant may be expanded while flowing through the expansion valve 320 such that the temperature thereof is lowered. The low-temperature refrigerant may be introduced into the first heat-exchanger 210, and may evaporate by taking the heat from washing water having a relatively high temperature in the first heat-exchanger 210. Accordingly, the first heat-exchanger 210 may operate as the evaporator 202 in the drying mode.
In this way, in order to recover heat energy from the high-temperature washing water using the first heat-exchanger 210, even after the washing mode is terminated, at least a predetermined amount or greater of the washing water is not drained out of the sump 4 and remains in the sump 4.
In one example, in the drying mode, as described above, the damper 632 pivots to a position at which the damper closes the first outlet 643 of the supply duct 640.
Accordingly, the air flow path Fa inside the supply duct 640 communicates with the fan housing of the blower fan 620.
Accordingly, when the blower fan 620 operates, the air discharged from the blower fan 620 via the second heat-exchanger 220 is introduced into the second inlet 642 of the supply duct 640, and then is supplied to the tub 2 via the second outlet 644.
After the air supplied to the tub 2 has dried the washing target, the air supplied to the tub 2 is discharged to the outside through the partially opened door 3 as shown in the drawing.
In one example, as the drying mode is performed, heat energy of the washing water stored in the sump 4 is recovered by the first heat-exchanger 210, and thus the temperature of the washing water is gradually lowered.
In this regard, in a state in which the washing water is stored in the sump 4, a water surface thereof is exposed to the air heated by the second heat-exchanger 220.
Therefore, the washing water is continuously circulated by the above-described washing pump 45. Thus, as the temperature of the washing water is gradually lowered, a significant amount or greater of the thermal energy of the heated air supplied to the tub 2 may be absorbed by the washing water.
That is, when a difference value between a temperature Tw of the washing water and a temperature Ta of the heated air exceeds a predetermined threshold value Tth, the drying efficiency may be deteriorated.
In order to prevent such a decrease in the drying efficiency, when the difference value between the temperature Tw of the washing water and the temperature Ta of the heated air exceeds the threshold value Tth, a portion of the washing water stored in the sump 4 may be drained out of the sump.
A first temperature sensor TS1 as a means for sensing the temperature Tw of the washing water and a second temperature sensor TS2 as a means for sensing the temperature Ta of the heated air may be provided.
By way of example, the first temperature sensor TS1 may be disposed in the sump 4, and the second temperature sensor TS2 may be disposed inside the tub 2 or on a side of the first inlet 641 of the supply duct 640 through which the heated air is introduced.
In this regard, the threshold value may be in a range of, for example, 8°C to 12°C.
For the drainage of the portion of the washing water, power may be supplied to the water discharge pump 442 connected to the sump 4 to initiate the operation of the pump.
However, in response to that too much washing water is drained out, the heat absorption performance of the first heat-exchanger 210 may deteriorate.
Therefore, the water discharge pump 442 may be configured to operate only for a predetermined set time duration Tp_th in order that an appropriate amount of the washing water is drained out.
In this regard, the predetermined set time duration Tp_th may be in a range of 30 seconds to 60 seconds.
As described above, when the water discharge pump 442 operates only for the predetermined set time duration such that the washing water is drained out, about 1 liter of washing water remains in the sump 4, and accordingly, the lower surface of the tub 2 constituting the bottom surface thereof may be exposed to the heated air without being submerged in the washing water.
Therefore, discharging the washing water only by a partial amount such that the lower surface of the tub 2 is exposed to the air may allow a contact area between the heated air and the washing water to be minimized, and allow the thermal energy to be absorbed by the washing water to be kept at a minimum level.
As described above, the progress of the drying mode may be continued in a state in which the partial portion of the washing water is drained out. After the remaining drying cycle time duration has elapsed, the operation of each of the compressor 100 and the blower fan 620 may be stopped, and the water discharge pump 442 may operate to drain an entirety of the remaining washing water, and then the drying cycle may be terminated.

[Configuration of Controller and Control Method of Dishwasher]

Hereinafter, a configuration of the controller 700 of the dishwasher 1 according to an embodiment of the present disclosure will be described with reference to FIG. 8.
As illustrated in FIG. 8, the dishwasher 1 according to an embodiment of the present disclosure may include the controller 700 for controlling each of the functional components.
The controller 700 may be embodied in various forms such as a microcontroller, a microcomputer, or a microprocessor, as known in the art.
First, the controller 700 may be electrically connected to the first temperature sensor TS1 for detecting the temperature Tw of the washing water during the drying mode.
As described above, the first temperature sensor TS1 may be disposed in the sump 4, and may generate an output signal including information on the temperature of the washing water which is stored in the sump 4 and circulates between the first heat-exchanger 210 and the sump 4.
The controller 700 may receive the output signal of the first temperature sensor TS1 and detect the current temperature Tw of the washing water based on the information included in the output signal.
In addition, the controller 700 may be electrically connected to the second temperature sensor TS2 for detecting the temperature Ta of the heated air during the drying mode.
As described above, the second temperature sensor TS 2 may be disposed inside the tub 2 or on the side of the first inlet 641 of the supply duct 640 through which the heated air is introduced.
The controller 700 may receive the output signal of the second temperature sensor TS2 and detect the current temperature Ta of the air based on the information included in the output signal.
In one example, the controller 700 may be electrically connected to the fan motor 621 of the blower fan 620.
The controller 700 may supply power to the fan motor 621 to operate the blower fan 620 to generate an air flow when the washing mode is performed and when the drying mode is performed. Thus, the heat-exchange may be performed between the second heat-exchanger 220 and the air flow.
In addition, the controller 700 may be electrically connected to the compressor 100.
The controller 700 may be configured to operate the compressor 100 by supplying power to the compressor 100 during the washing mode and the drying mode, and thus the circulation of the refrigerant may be maintained.
In addition, the controller 700 may be electrically connected to the washing pump 45.
The controller 700 may be configured to operate the washing pump 45 by supplying power to the washing pump 45 during the washing mode and the drying mode, and thus the circulation of the washing water between the first heat-exchanger 210 and the sump 4 may be maintained.
As described above, when the drying mode is performed, the controller 700 may be configured to control the washing pump 45 to operate in an operation mode different from the operation mode when the washing mode is performed.
In one example, when the drying mode is performed, the controller 700 may be configured to operate the washing pump 45 in a mode in which the number of rotations is lower than that in when the washing cycle or the rinsing cycle is performed, or may be configured to operate the washing pump 45 in a mode in which the operation-stop is repeated at a predetermined period.
In this regard, the predetermined period may be in a range of, for example, 5 seconds to 10 seconds, and the lower rotation speed may be in a range of 800 RPM to 1000 RPM.
In addition, the controller 700 may be electrically connected to the water discharge pump 442.
The controller 700 may be configured to operate the water discharge pump 442 by supplying power to the water discharge pump 442 at a time point at which a washing cycle S2 has ended and a time point at which a rinsing cycle S3 has ended. When the water discharge pump 442 operates, the washing water stored in the sump 4 may be discharged to the outside out of the sump.
However, in order to recover the heat energy of the heated washing water as described above, the controller 700 may be configured to control the water discharge pump 442 not to operate at a time point at which the heating rinsing process has been terminated.
The controller 700 may determine whether to drain the washing water, that is, whether to activate the operation of the water discharge pump 442, based on a difference value between the temperature Tw of the washing water and the temperature Ta of the heating air supplied to the tub 2 after the heat pump apparatus 10 has operated in the drying mode after the drying cycle has been started. A detailed configuration related to determining whether to drain the washing water during the drying mode will be described later with reference to FIGS. 10 and 11.
In addition, the controller 700 may be electrically connected to the four-way valve 400a.
As described above, when the heat pump apparatus 10 operates in the washing mode, the controller 700 may be configured to control the four-way valve 400a to connect the first pipe 410 and the first pipe 420 to each other and connect the fourth pipe 440 and the fifth pipe 450 to each other. When the heat pump apparatus 10 operates in the drying mode, the controller 700 may be configured to control the four-way valve 400a to connect the first pipe 410 and the fourth pipe 440 to each other and connect the first pipe 420 and the fifth pipe 450 to each other.
In addition, the controller 700 may be electrically connected to the damper 632.
As described above, the controller 700 may be configured to allow the damper 632 to pivot to a first position to close the first outlet 643 of the supply duct 640 and to open the second inlet 642 of the supply duct 640 when the drying mode is performed. The controller 700 may be configured to allow the damper 632 to pivot to a second position to close the second inlet 642 of the supply duct 640 and open the first outlet 643 when the washing mode is performed.
In one example, the controller 700 is electrically connected to a memory and a timer. The controller 700 fetches an operation condition and a time condition on each cycle pre-stored in the memory, and generates a control signal for controlling a start and an end of each cycle based on the fetched conditions. Furthermore, the memory may further store therein information on the threshold value Tth of the temperature difference value used for partially draining the washing water during the drying mode, and information on the set time duration Tp_th for which the water discharge pump 442 operates for partially draining the washing water.
In addition, the controller 700 may be configured to calculate an elapsed time duration of each cycle using the timer, and determine whether each cycle has been completed based on a comparing result thereof with a pre-stored time condition about each cycle. In this regard, the cycles may include a pre-washing cycle, a washing cycle, a rinsing cycle, a heating rinsing cycle, and a drying cycle as shown in FIG. 9. In addition, the controller 700 may measure an elapsed time duration Tp of the operation of the water discharge pump 442 for partial drainage of the washing water using the timer.
Hereinafter, a control method of the dishwasher 1 according to the present disclosure will be described with reference to FIGS. 9 to 11.
As illustrated in FIG. 9, the controller 700 is configured to control the overall operations of the dishwasher 1 in the order of the pre-washing cycle S2, the washing cycle S2, the rinsing cycle S3, the heating rinsing cycle S4, and the drying cycle S5.
FIG. 10 illustrates detailed operations of the drying cycle S5 of the dishwasher 1 according to an embodiment of the present disclosure.
Referring to FIG. 10, in order to switch the operation of the heat pump apparatus 10 to the drying mode at the same time as the drying operation is started, the controller 700 may change the state of the four-way valve 400a to switch the refrigerant flow path Fr and supply power to the compressor 100 to operate the compressor 100 in S41.
In the operation S41, when the refrigerant flow path Fr is switched and the operation of the compressor 100 is started, the controller 700 supplies the air heated by the second heat-exchanger 220 to the tub 2 in S42.
To this end, the controller 700 may be configured to control the damper 632 to pivot to close the first outlet 643 of the supply duct 640 and open the second inlet 642 of the supply duct 640 to switch the internal flow path of the supply duct 640. In addition, the controller 700 may start the operation of the fan motor 621 of the blower fan 620 to generate an airflow of the air heated while flowing through the second heat-exchanger 220.
When the supply of the heated air is started in the operation S42, the controller 700 starts the heat-exchange between the washing water and the refrigerant in the first heat-exchanger 210 in S43.
More specifically, as shown in FIG. 11, in order to initiate heat-exchange between the washing water and the refrigerant in the first heat-exchanger 210, the controller 700 may be configured to supply power to the washing pump 45 to initiate the operation of the washing pump 45 in S431.
When the operation of the washing pump 45 is started in the operation S431, the controller 700 may maintain the operation of the washing pump 45 to operate in an operation mode different from the operation mode executed when the washing mode is performed in S432.
That is, the controller 700 is configured to control the heat pump apparatus 10 so that the flow of the washing water is not stopped and is continuously circulated during the drying mode.
However, the controller 700 may be configured to control the washing pump 45 so that the washing water is not sprayed to the tub 2 during the drying mode, but the circulation of the washing water is maintained.
To this end, the controller 700 may be configured to control the washing pump 45 to operate in a lower rotation speed mode having a speed lower than that in when the washing cycle or the rinsing cycle is performed or to operate in a mode in which the operation-stop is repeated at a predetermined period.
In this regard, the lower rotation speed may be in a ranger of, for example, 800 RPM to 1000 RPM.
In addition, the predetermined period may be in a range of 5 seconds to 10 seconds.
In one example, when the heat-exchange between the washing water and the refrigerant is started in the operation S43, the controller 700 may be configured to determine whether to drain the washing water stored in the sump, based on a difference value between the temperature Tw of the washing water and the temperature Ta of the air heated by the second heat-exchanger 220 in S44.
FIG. 11 illustrates detailed operations of the operation S44.
Referring to FIG. 11, the controller 700 may receive output signals from the first temperature sensor TS1 and the second temperature sensor TS2, respectively in S441.
Next, the controller 700 may be configured to receive the output signal of the first temperature sensor TS1 and detect the current temperature Tw of the washing water based on information included in the output signal of the first temperature sensor TS1, and to receive the output signal of the second temperature sensor TS2 and detect the current temperature Ta of the air based on information included in the output signal of the second temperature sensor TS2 in S442.
The controller 700 is configured to calculate a difference value between the detected temperature Tw of the washing water and the detected temperature Ta of the heated air obtained in the operation S442, and compares the calculated difference value with a predetermined threshold value Tth in S443.
In this regard, the predetermined threshold value may be in a range of, for example, 8°C to 12°C.
Upon determination that the difference value calculated in the operation S443 is greater than or equal to the predetermined threshold value Tth, the controller 700 is configured to determine to drain a portion of the washing water stored in the sump 4 and proceeds with partial drainage of the washing water in S444, S445, S446, and S447.
More specifically, the controller 700 may be configured to supply power to the water discharge pump 442 to start the drainage of the washing water to start the operation of the water discharge pump 442 in S444.
When the operation of the water discharge pump 442 is started in the operation S444, the controller 700 is configured to measure the elapsed time duration Tp of the operation of the pump 442 after the operation of the water discharge pump 442 has been started using the timer in S445.
In response to that, in the operation S445, the measurement of the elapsed time is started, the controller 700 compares the elapsed operation time duration Tp with the predetermined set time duration Tp_th in S446.
In response to that, based on a result of the comparison in the operation S446, it is determined that the measured elapsed operation time duration Tp is greater than or equal to the predetermined set time duration Tp_th, the controller 700 is configured to cut off the power supply to the water discharge pump 442 and stop the operation of the water discharge pump 442 in S447.
That is, the controller 700 may determine a water amount to be discharged, based on the elapsed operation time duration Tp of the water discharge pump 442. When it is identified that the predetermined set time duration Tp_th has elapsed, it is determined that a target water amount to be discharged has been discharged out and thus the drainage of the washing water may be stopped.
In this regard, the predetermined set time duration Tp_th may be in a range of 30 seconds to 60 seconds.
As described above, when the water discharge pump 442 operates only for the predetermined set time duration Tp_th to drain the washing water, about 1 liter of washing water remains in the sump 4, and accordingly, the lower surface of the tub 2 constituting the bottom surface of the tub may be exposed to the heated air without being submerged in the washing water.
Therefore, discharging the washing water only by a partial amount such that the lower surface of the tub 2 is exposed to the air may allow a contact area between the heated air and the washing water to be minimized, and allow the thermal energy to be absorbed by the washing water to be kept at a minimum level.
Otherwise, in response to that it is determined in the operation S446 that the elapsed operation time duration does not reach the predetermined set time duration Tp_th, the controller 700 may be configured to continue to execute the operation S445.
As described above, when the partial drainage of the washing water stored in the sump 4 has been completed, the controller 700 is configured to continuously operate the heat pump apparatus 10 in the drying mode until the remaining drying cycle time duration has elapsed. When it is identified using the timer that the remaining drying cycle time duration has elapsed, the air supply to the tub 2 may be stopped in S45. This is illustrated in FIG. 10.
The controller 700 may be configured to stop the operation of the heat pump apparatus 10 together with stopping the air supply. To this end, power supply to the fan motor 621 of the blower fan 620 may be stopped, power supply to the compressor 100 may be stopped, and power supply to the washing pump 45 may be stopped.
Next, the controller 700 may be configured to supply power to the water discharge pump 442 again to operate the water discharge pump 442 in order to discharge the remaining portion of the washing water out of the sump 4 in S46.
In this regard, this operation is the water draining operation for terminating the drying process. Thus, the operation of the water discharge pump 442 may be continued until an entirety of the remaining portion of the washing water has been drained out of the sump.
As described above, while the controller does not drain the washing water heated during the washing mode, the heat pump apparatus 10 of the dishwasher 1 according to the present disclosure is configured to recover the thermal energy of the washing water through the heat-exchanger acting as the evaporator during the drying mode, thereby improving the energy efficiency of the heat pump apparatus. When the temperature of the washing water falls below a predetermined level, the controller partially drains the washing water, thereby preventing deterioration of the drying efficiency.
Although the embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not necessarily limited to these embodiments, and may be modified in a various manner within the scope of the technical spirit of the present disclosure. Accordingly, the embodiments as disclosed in the present disclosure are intended to describe rather than limit the technical idea of the present disclosure, and the scope of the technical idea of the present disclosure is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are not restrictive but illustrative in all respects. In addition, even though an effect of a configuration of the present disclosure is not explicitly described in describing the embodiment of the present disclosure above, it is obvious that the predictable effect from the configuration should be recognized.

Claims

A dishwasher comprising:
a tub having a washing space defined therein, wherein dishes are received in the washing space;

a heat pump apparatus including:
a compressor for compressing refrigerant;

a first heat-exchanger configured to:
receive the refrigerant having flowed through the compressor and heat the washing water to be supplied to the tub in a washing mode of the dishwasher; and

receive heat from the washing water and evaporate the refrigerant to be supplied to the compressor using the heat in a drying mode of the dishwasher; and

a second heat-exchanger configured to receive the refrigerant having flowed through the compressor and evaporate air to be supplied to the tub in the drying mode;

a sump for storing therein the washing water heated by the first heat-exchanger; and

a controller configured to determine whether to drain the washing water stored in the sump in the drying mode of the dishwasher,

wherein the controller is further configured to:
circulate the washing water between the sump and the first heat-exchanger to exchange heat between the first heat-exchanger and the refrigerant in the drying mode; and

determine whether to drain the washing water stored in the sump, based on a difference value between a temperature of the washing water and a temperature of the air heated by the second heat-exchanger, in the drying mode.
The dishwasher of claim 1, wherein the determining of whether to drain the washing water includes:
calculating a difference value between the temperature of the washing water and the temperature of the heated air, and comparing the calculated difference value with a predetermined threshold value; and

upon determination based on the comparing result that the calculated difference value is greater than or equal to the predetermined threshold value, determining to drain a portion of the washing water.
The dishwasher of claim 2, wherein the dishwasher further comprises:
a first temperature sensor configured to sense the temperature of washing water in the drying mode; and

a second temperature sensor configured to sense the temperature of the air heated by the second heat-exchanger in the drying mode,

wherein the determining of whether to drain the washing water includes:
receiving output signals from the first temperature sensor and the second temperature sensor, respectively; and

detecting the temperature of the washing water and the temperature of the heated air, based on the output signal of the first temperature sensor and the output signal of the second temperature sensor, respectively.
The dishwasher of claim 2, wherein the predetermined threshold value is in a range of 8°C to 12°C.
The dishwasher of claim 2, wherein the dishwasher further comprises:
a water discharge pump configured to discharge the washing water stored in the sump to the outside; and

a timer for measuring an operation time of the water discharge pump,

wherein the draining of the portion of the washing water includes:
supplying power to the water discharge pump to start an operation of the water discharge pump;

measuring, using the timer, an elapsed time duration after the operation of the water discharge pump is started;

comparing the elapsed time duration with a predetermined set time duration; and

upon determination that the measured elapsed time duration is greater than or equal to the predetermined set time duration, cutting off the power supply to the water discharge pump and stopping the operation of the water discharge pump.
The dishwasher of claim 5, wherein the predetermined set time duration is in a range of 30 seconds to 60 seconds.
The dishwasher of claim 1, wherein the dishwasher further comprises a pump connected to each of the sump and the first heat-exchanger and configured to circulate the washing water between the sump and the first heat-exchanger,
wherein the exchanging of the heat between the first heat-exchanger and the refrigerant in the drying mode includes:
supplying power to the pump to start an operation of the pump; and

maintaining the operation of the pump in an operation mode different from an operation mode of the pump in the washing mode.
The dishwasher of claim 7, wherein the operation mode different from the operation mode of the pump in the washing mode includes:
a mode in which the pump operates at a rotation speed lower than a rotation speed in the washing mode; or

a mode in which an operation-a stop of the pump is repeated at a predetermined period.
The dishwasher of claim 8, wherein the lower rotation speed is in a range of 800 RPM to 1000 RPM.
The dishwasher of claim 8, wherein the predetermined period is in a range of 5 to 10 seconds.
A method for controlling a dishwasher, wherein the dishwasher includes:
a tub having a washing space defined therein, wherein dishes are received in the washing space;

a heat pump apparatus including:
a compressor for compressing refrigerant;

a first heat-exchanger configured to:
receive the refrigerant having flowed through the compressor and heat the washing water to be supplied to the tub in a washing mode of the dishwasher; and

receive heat from the washing water and evaporate the refrigerant to be supplied to the compressor using the heat in a drying mode of the dishwasher; and

a second heat-exchanger configured to receive the refrigerant having flowed through the compressor and evaporate air to be supplied to the tub in the drying mode; and

a sump for storing therein the washing water heated by the first heat-exchanger, wherein the method comprises:
circulating the washing water between the sump and the first heat-exchanger to exchange heat between the first heat-exchanger and the refrigerant, in the drying mode; and

determining whether to drain the washing water stored in the sump, based on a difference value between a temperature of the washing water and a temperature of the air heated by the second heat-exchanger, in the drying mode.
The method for controlling the dishwasher of claim 11, wherein the determining of whether to drain the washing water includes:
calculating a difference value between the temperature of the washing water and the temperature of the heated air, and comparing the calculated difference value with a predetermined threshold value; and

upon determination based on the comparing result that the calculated difference value is greater than or equal to the predetermined threshold value, determining to drain a portion of the washing water.
The method for controlling the dishwasher of claim 12, wherein the determining of whether to drain the washing water includes:
receiving output signals from a first temperature sensor and a second temperature sensor, respectively, wherein the first temperature sensor is configured to sense the temperature of washing water in the drying mode, and the second temperature sensor is configured to sense the temperature of the air heated by the second heat-exchanger in the drying mode; and

detecting the temperature of the washing water and the temperature of the heated air, based on the output signal of the first temperature sensor and the output signal of the second temperature sensor, respectively.
The method for controlling the dishwasher of claim 12, wherein the predetermined threshold value is in a range of 8°C to 12°C.
The method for controlling the dishwasher of claim 12, wherein the draining of the portion of the washing water includes:
supplying power to a water discharge pump to start an operation of the water discharge pump, wherein the water discharge pump is configured to discharge the washing water stored in the sump to the outside;

measuring, using a timer, an elapsed time duration after the operation of the water discharge pump is started;

comparing the elapsed time duration with a predetermined set time duration; and

upon determination that the measured elapsed time duration is greater than or equal to the predetermined set time duration, cutting off the power supply to the water discharge pump and stopping the operation of the water discharge pump.
The method for controlling the dishwasher of claim 15, wherein the predetermined set time duration is in a range of 30 seconds to 60 seconds.
The method for controlling the dishwasher of claim 11, wherein the exchanging of the heat between the first heat-exchanger and the refrigerant in the drying mode includes:
supplying power to the pump to start an operation of the pump, wherein the pump is connected to each of the sump and the first heat-exchanger and is configured to circulate the washing water between the sump and the first heat-exchanger; and

maintaining the operation of the pump in an operation mode different from an operation mode of the pump in the washing mode.
The method for controlling the dishwasher of claim 17, wherein the operation mode different from the operation mode of the pump in the washing mode includes:
a mode in which the pump operates at a rotation speed lower than a rotation speed in the washing mode; or

a mode in which an operation-a stop of the pump is repeated at a predetermined period.
The method for controlling the dishwasher of claim 18, wherein the lower rotation speed is in a range of 800 RPM to 1000 RPM.
The method for controlling the dishwasher of claim 18, wherein the predetermined period is in a range of 5 to 10 seconds.