WO2020069802A1

WO2020069802A1 - A heat pump dishwasher comprising a defrost system

Info

Publication number: WO2020069802A1
Application number: PCT/EP2019/073043
Authority: WO
Inventors: Onur Poyraz; Emre SAGLICAN; Erkan KUTUK; Ayla Kuran; Nevin AKKAS
Original assignee: Arcelik Anonim Sirketi
Priority date: 2018-10-02
Filing date: 2019-08-29
Publication date: 2020-04-09

Abstract

The present invention relates to a heat pump (5) type dishwasher (1) comprising a tub (2); a circulation pump (18) which provides the delivery of the washing water into the washing environment in the tub (2); a sump (3) which is disposed under the tub (2) and wherein the washing water is collected; a discharge pump (4) which enables the water collected in the sump (3) at the end of the washing process to be discharged to the outside; a compressor (6); a condenser (7); an evaporator (8); a water tank (9) wherein the evaporator (8) is placed and from which the evaporator (8) transfers heat, wherein the problem of freezing in the water tank (9) is eliminated.

Description

A HEAT PUMP DISHWASHER COMPRISING A DEFROST SYSTEM

The present invention relates to a heat pump dishwasher.

The heat pump system in the heat pump dishwashers is composed of a compressor which provides the circulation of a refrigerant (refrigerant fluid), a condenser, an evaporator, and an expansion element. Said components are connected to each other by means of a pipe line, and by means of the fluid passing through the pipe line, the cycle is performed. The aim of said cycle is to heat the washing water. To this end, the evaporator draws heat from the environment to the heat pump system, and the condenser transfers the heat of the heat pump system to the washing water. In some embodiments, the evaporator is operated in the water in a water tank and transfers heat from the water. The refrigerant passing through the evaporator cools down the evaporator tubes. The cooled down evaporator tubes draw heat from the water surrounding the same. In a heat pump dishwasher which is operated in this manner, the temperature on the evaporator tubes and around the evaporator tubes decreases as long as the heat pump is operated, and the water in the water tank which contains the evaporator may freeze. If the water freezes, the heat pump cannot draw heat from outside and the efficiency of the system decreases. In this case the heat pump cannot heat the washing water to the desired temperature, and the washing performance decreases. Moreover, as the time required for heating the water increases, the program duration and energy consumption also increase. In one washing cycle, the washing water is heated more than once. In this case, the ice in the evaporator water tank may be still unthawed when the washing water is needed to be heated again, and especially in washing processes with repeated steps and quick programs, the heat pump system cannot be used since the evaporator water tank is not ready. Instead, the conventional heater is operated to heat the water, which increases energy consumption.

The Patent No. EP2594185 (B1) relates to a heat pump dishwasher. The evaporator operates in the waste water tank, and thus the heat pump draws heat from the water in the waste water tank.

The Patent No. EP2658430 (B1) relates to a heat pump dishwasher. The evaporator and the condenser are disposed in separate water tanks.

The aim of the present invention is the realization of a heat pump dishwasher wherein the problem of freezing in the evaporator is eliminated, thus decreasing energy consumption.

The dishwasher realized in order to attain the aim of the present invention is of heat pump type, and comprises a compressor, a condenser, and an evaporator. The evaporator is operated in a tank and draws heat from the water in the tank. In the embodiment of the present invention, a defrost system, which has a heat reservoir enclosing the water tank wherein the evaporator operates, is used, thus preventing the water in the water tank from freezing.

In an embodiment of the present invention, the hot and waste water in the sump under the tub, that is the waste water tank, is used as the hot water source in the heat reservoir in the defrost system.

In another embodiment of the present invention, the heat reservoir in the defrost system is in the form of a helical tube wound around the water tank.

In another embodiment of the present invention, the water which is located in the water pocket wherein water is collected before the washing process and which is heated at least up to the ambient temperature or the water condensing in the drying duct is used in the heat reservoir in the defrost system.

The heat pump dishwasher realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 - is the schematic view of a state of the art heat pump dishwasher.

Figure 2 – is the detailed schematic view of the dishwasher in an embodiment of the present invention.

Figure 3 – is the detailed schematic view of the dishwasher in another embodiment of the present invention.

Figure 4 – is the detailed schematic view of the dishwasher in another embodiment of the present invention.

Figure 5 – is the detailed schematic view of the dishwasher in another embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

Dishwasher
Tub
Sump
Discharge pump
Heat pump
Compressor
Condenser
Evaporator
Water tank
Heat reservoir
Hot water line
Defrost system
Water pocket
Defrost pump
Drying duct
Electronic card
Container
Circulation pump
Rack
Expansion element

The dishwasher (1) comprises a tub (2); a circulation pump (18) which provides the delivery of the washing water into the washing environment in the tub (2); a sump (3) which is disposed under the tub (2) and wherein the washing water is collected; a discharge pump (4) which enables the water collected in the sump (3) at the end of the washing process to be discharged to the outside; at least one rack (19) wherein the dishes to be washed are loaded; and a heat pump (5) which heats the washing water.

The heat pump (5) comprises a compressor (6) which performs the refrigerant cycle; a condenser (7) which is used for heating the washing water; an evaporator (8) which draws heat from the outer environment; a water tank (9) wherein the evaporator (8) is placed and the evaporator (8) draws heat from the water with which the latter is in contact; and an expansion element (20), for example a capillary tube or an expansion valve, which is disposed between the condenser (7) and the evaporator (8) and which decreases the pressure of the refrigerant (Figure 1).

The dishwasher (1) of the present invention comprises a defrost system (12) which has a heat reservoir (10) which encloses the water tank (9) wherein the evaporator (8) is placed, and a hot water line (11) which enables the water used in the washing water to be delivered to the heat reservoir (10).

The defrost system (12) provides that the water in the water tank (9) wherein the evaporator (8) is placed and from which the evaporator (8) draws heat is heated and hence the ice formed in the water tank (9) during the operation of the heat pump (5) is thawed.

In an embodiment of the present invention, in the defrost system (12), the waste washing water collected in the sump (3) is delivered to the heat reservoir (10) by means of the discharge pump (4) and the hot water line (11) (Figure 2).

In this embodiment, at the end of the main washing and/or hot rinsing process in the dishwasher, the hot waste water is used for melting the frozen water in the water tank (9) of the evaporator (8) before being discharged. After being collected in the sump (3), the washing water is delivered to the heat reservoir (10) enclosing the water tank (9) by means of the discharge pump (4). The heat reservoir (10) which is heated with the hot discharge water first melts the ice in the water tank (9), then heats the water. After the heat of the water is transferred to the water tank (9), the water in the heat reservoir (10) is discharged.

At the end of the hot rinsing step just like at the end of the main washing process, while being discharged from the sump (3), the hot washing water is delivered to the heat reservoir (10) enclosing the water tank (9). The ice in the water tank (9) is thawed with the heat of the waste water, and then the water is heated. At the end of the main washing step, the heated water in the water tank (9) makes the evaporator (8), hence the heat pump (5) ready for the next process which is the hot rinsing step. At the end of the hot rinsing step, the heated water in the water tank (9) makes the heat pump (5) ready for the next washing program. Thus, the heat pump (5) can be used both in quick programs and repeated operations in the dishwasher (1), and the need for operating a heater, which consumes too much energy, to heat the washing water is eliminated.

In an embodiment of the present invention, the heat reservoir (10) is in the form of a helical pipe surrounding the water tank (9) wherein the evaporator (8) is placed. The washing water which is collected in the sump (3) after the main washing and hot rinsing steps is passed through the heat reservoir (10) and circulated around the water tank (9), thus heating the water tank (9) (Figure 3).

In another embodiment of the present invention, the dishwasher (1) comprises a water pocket (13) which enables the water to be collected before the washing process and brought to the ambient temperature and thus shortening the water heating time during the washing process and providing savings in energy, and the water in the water pocket (13) is delivered to the heat reservoir (10) by means of the hot water line (11) and a defrost pump (14) so as to be used in the defrost system (12) (Figure 5).

The water pocket (13) positioned on the side of the dishwasher (1) is used for keeping and heating the water which is taken from the mains and which is colder (15°C) than the ambient air (23°C) by means of the ambient air. The water which is heated up to the ambient temperature in the water pocket (13) can be used in the defrost system (12), and the ice in the water tank (9) in the evaporator (8) can be melted.

In another embodiment of the present invention, the dishwasher (1) comprises a drying duct (15) which takes the humid air in the tub (2) out of the tub (2) after the washing process and thus enables the washed items to be dried, and the defrost system (12) which enables the water in the drying duct (15) to be delivered into the heat reservoir (10) by means of the hot water line (11) and the defrost pump (14).

In another embodiment of the present invention, the dishwasher (1) comprises the defrost system (12) which enables the water, which is present in a container (17) which is disposed on the compressor (6) and/or the electronic card (16) controlling the compressor (6) and which is heated by the compressor (6) and/or the electronic card (16) during the operation of the heat pump (5), to be delivered to the heat reservoir (10) by means of the hot water line (11) and the defrost pump (14) (Figure 4).

The container (17) is in contact with the compressor (6) and/or the electronic card (16) of the compressor (6). The water in the container (17) can heat up quickly by drawing the heat of the compressor (6) and/or the components on the electronic card (16), thus preventing malfunctions which may occur on the electronic card (16) and cooling down the compressor (6).

In the dishwasher (1) of the present invention, the defrost system (12) eliminates the problem of freezing in the water tank (9) wherein the evaporator (8) is placed. The heat pump (5) is kept ready for operation, the dishwasher (1) can be operated successively, and the need for a heating element in addition to the heat pump (5) to heat the washing water is eliminated.

Claims

A dishwasher (1) comprising a tub (2); a sump (3) which is disposed under the tub (2) and wherein the washing water is collected; a discharge pump (4) which enables the water collected in the sump (3) at the end of the washing process to be discharged to the outside; a heat pump (5) which heats the washing water; and a compressor (6), a condenser (7), an evaporator (8) which draws heat from the outside and a water tank (9) wherein the evaporator (8) is placed, which all together constitute the heat pump (5), characterized by a defrost system (12) which has a heat reservoir (10) which encloses the water tank (9), and a hot water line (11) which enables the water used in the washing water to be delivered to the heat reservoir (10).
A dishwasher (1) as in Claim 1, characterized by the defrost system (12) which has the heat reservoir (10) to which the waste washing water collected in the sump (3) is delivered by means of the discharge pump (4) and the hot water line (11).
A dishwasher (1) as in Claim 1 or 2, characterized by the defrost system (12) which has the heat reservoir (10) in the form of a helical tube surrounding the water tank (9) wherein the evaporator (8) is placed.
A dishwasher (1) as in Claim 1, characterized by a water pocket (13) wherein the water is collected before the washing process, and by the defrost system (12) which has the heat reservoir (10) to which the water in the water pocket (13) is delivered by means of the hot water line (11) and a defrost pump (14).
A dishwasher (1) as in Claim 1, characterized by a drying duct (15) which takes the humid air in the tub (2) out of the tub (2) so as to be condensed, and by the defrost system (12) which has the heat reservoir (10) to which the water condensed in the drying duct (15) is delivered by means of the hot water line (11) and the defrost pump (14).
A dishwasher (1) as in Claim 1, characterized by the defrost system (12) which has the heat reservoir (10) to which the water in a container (17), which is heated by the compressor (6) and/or the electronic card (16) controlling the compressor (6), is delivered by means of the hot water line (11) and the defrost pump (14).