Household appliance

Abstract

Provided herein are a household appliance and a method for using a heat pump in a household appliance, which may include a household appliance for washing and drying goods. The household appliance may include a processing chamber for receiving goods to be washed and dried, and a heat pump having a warm side provided with a condenser and a cold side provided with an evaporator, wherein the condenser may be adapted to heat water to be used in the processing chamber and the evaporator may be adapted to cool a liquid in a heat reservoir for storing heat generated on the cold side of the heat pump during heating of the condenser. The condenser may be arranged in a water tank adapted to provide water to the processing chamber.

Claims

1. A household appliance for washing and drying goods, comprising a processing chamber for receiving goods to be washed and dried; a main water inlet fluidly connected to the processing chamber; a water tank connected to the main water inlet and the processing chamber between the main water inlet and the processing chamber, such that the water tank is configured to receive and hold water from the main water inlet before the water reaches the processing chamber, and a heat pump having a warm side provided with a condenser and a cold side provided with an evaporator, wherein the condenser is adapted to heat water to be used in the processing chamber and the evaporator is adapted to cool a liquid in a heat reservoir for storing heat generated on the cold side of the heat pump during heating with the condenser, wherein the condenser is arranged in the water tank adapted to provide water into the processing chamber, and wherein the heat reservoir is thermally connected to the processing chamber, such that the heat reservoir is configured to cool air in the processing chamber.

2. The household appliance according to claim 1, wherein the heat reservoir is thermally connected to the processing chamber via a heat exchanging device, and the heat exchanging device provides a surface for condensing thereon water vapour from the processing chamber during drying of the goods in the processing chamber.

3. The household appliance according to claim 2, wherein the heat exchanging device comprises a cooling conduit which is connected to the heat reservoir and which is at least partly arranged inside the heat reservoir.

4. The household appliance according to claim 3, wherein the cooling conduit is at least partially arranged inside the processing chamber, such that the cooling conduit is configured to thermally connect the heat reservoir with the processing chamber.

5. The household appliance according to claim 2, wherein the heat exchanging device is a heat pipe or a thermosiphon.

6. The household appliance according to claim 3, wherein the cooling conduit comprises a pump for circulating a heat transfer liquid through the cooling conduit such that the heat transfer liquid is cooled while passing through the heat reservoir.

7. The household appliance according to claim 3, wherein the cooling conduit is spirally shaped in the heat reservoir.

8. The household appliance according to claim 2, wherein the heat exchanging device is arranged within the processing chamber.

9. The household appliance according to claim 2, wherein the heat reservoir is arranged outside the processing chamber.

10. The household appliance according to claim 1, wherein the heat reservoir is arranged within the processing chamber.

11. The household appliance according to claim 10, wherein the heat reservoir comprises a condenser surface onto which water vapour from the processing chamber condenses during drying of the goods in the processing chamber.

12. The household appliance according to claim 1, wherein the appliance comprises an air flow generating device for directing air and/or water vapour towards the heat exchanging device or condenser surface.

13. The household appliance according to claim 1, wherein the liquid in the heat reservoir is water.

14. The household appliance according to claim 1, wherein the household appliance is a dishwasher for washing, rinsing and drying dish goods.

15. The household appliance according to claim 1, wherein the household appliance is a washer-dryer for washing, rinsing and drying laundry.

16. The household appliance according to claim 1, further comprising a partitioning wall in the processing chamber separating a main part of the processing chamber from a cooling area of the processing chamber, and a fan configured to direct air from the main part of the processing chamber to the cooling area of the processing chamber, wherein the heat reservoir is thermally connected to the cooling area of the processing chamber.

17. The household appliance according to claim 1, further comprising at least one valve configured to selectively direct water from the main water inlet to either of the water tank or the processing chamber.

18. The household appliance according to claim 1, further comprising a wash pump configured to circulate liquid from the processing chamber to at least one wash arm, and a heater configured to heat the liquid in the processing chamber proximate the wash pump, wherein the water tank is connected to the wash arm, such that the wash pump and the water tank are each configured to independently supply liquid to the wash arm.

19. A method for using a heat pump in a household appliance, the appliance comprising a processing chamber for receiving goods to be washed and dried, and the heat pump comprising a condenser and an evaporator, the method comprises the steps of: receiving and holding water in a tank from a main water inlet upstream of the processing chamber, heating the water in the tank with the condenser to be used in the processing chamber, cooling a liquid in a heat reservoir with the evaporator, storing heat in the form of cooled or frozen liquid in the heat reservoir, supplying the heated water in the tank into the processing chamber, and cooling air in the processing chamber with the cooled or frozen liquid in the heat reservoir.

20. The method according to claim 19, wherein the method comprises a further step of: condensing water vapour from the processing chamber on a heat exchanging surface arranged in contact with the heat reservoir.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

(2) FIG. 1 is a schematic illustration of a household appliance, i.e. a dishwasher, according to an embodiment,

(3) FIG. 2 is a schematic illustration of a household appliance, i.e. a washer-dryer, according to an embodiment,

(4) FIG. 3 shows a dishwasher according an embodiment,

(5) FIG. 4 shows a dishwasher according to another embodiment, and

(6) FIG. 5 shows a flow chart of a method for using a heat pump in a household appliance.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) The present invention now will be described more fully with reference to the accompanying drawings, in which example embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art to which this invention belongs. Throughout the following description similar reference numerals have been used to denote similar elements, parts, items or features, when applicable.

(8) In FIGS. 1-2 schematic drawings of household appliances 1 are illustrated. In FIG. 1 a dishwasher 2 is schematically shown. In FIG. 2 a washer-dryer 3 is schematically shown. In both these household appliances washing and drying of goods take place. In the washing phase warm water together with a detergent are used to wash and thereby remove dirt from the goods in a processing chamber. In a later following drying phase, the goods are dried and hot water vapour is to be removed from the processing chamber.

(9) In FIG. 1 the dishwasher 2 comprises a processing chamber 5 to be loaded with dish goods. The dish washer further comprises a water tank 7 providing water to be used in the washing of the goods. To warm the water in the water tank, a heat pump 9 is arranged in the household appliance. Depending on program design, heat pump power, and wash temperature, the heat pump alone might be insufficient to heat up the water to the intended process temperature in the available time. Therefore, a conventional electrical heater (not shown) may be comprised in the household appliance as well. The heat pump 9 comprises a condenser 11, representing the warm side of the heat pump and an evaporator 13, representing the cold side of the heat pump. The condenser 11 is arranged in the water tank 7 for warming the water therein. The evaporator 13 is arranged in a heat reservoir 15. The heat reservoir may be a closed container which is filled with a liquid. The liquid in the heat reservoir may be water. However, it should be noted that other types of liquids or phase change materials may be chosen that have phase transition temperatures/enthalpies and/or specific heat in a suitable range in relation to the particular household appliance.

(10) The water tank 7 may be designed to be separate from the processing chamber 5 and thus arranged outside the processing chamber. However, it should be noted that the water tank may be designed to be integrated completely or partially into the processing chamber, for example in that the water tank is formed in the bottom region of the processing chamber but still as a separate space.

(11) The condenser/evaporator 11, 13 being arranged as a condenser/evaporator conduit is filled with a heat transfer fluid, such as a refrigerant. The heat pump 9 further comprises a compressor (8) and a pressure lowering device, such as an expansion valve (not shown). In a working mode of the heat pump, heat is generated on the warm side, i.e. in the condenser and cold is generated on the cold side, i.e. in the evaporator. The warm condenser warms up the water in the water tank and, at the same time, the cold evaporator cools the liquid in the heat reservoir. In the heat reservoir 15, a layer of frozen liquid builds up around the evaporator 13. In the case the heat reservoir is filled with water, ice is formed in the heat reservoir. Depending on the cooling effect in the evaporator and the time used to heat the water in the tank, the amount of ice in the heat reservoir may vary. The ice formed in the heat reservoir 15 is stored during the washing cycle. It should be noted that the liquid in the heat reservoir may be storing heat without being frozen. Depending on the type of liquid provided in the heat reservoir, the liquid may be cooled, also under zero degrees Celsius, without freezing.

(12) A heat exchanging device 17 is arranged in connection with the heat reservoir 15. The heat exchanging device comprises a cooling conduit 19. The cooling conduit is arranged in the heat reservoir. A pump 21 is arranged to the cooling conduit for circulating the heat exchanging fluid to and from the heat reservoir. The flow of cold heat transfer fluid in the cooling conduit cools the cooling conduit as well as the heat exchanging device connected thereto. The heat exchanging device may comprise cooling flanges or other area enlarging means (not shown) to provide a large area or surface for heat transfer. When the washing phase is terminated, the goods in the processing chamber should be dried. In the dishwasher, drying is performed by removing hot water vapour from the processing chamber. By moving the air in the processing chamber towards the heat exchanging device, a flow of air containing hot water vapour meets the cold surface of the heat exchanging device. The hot water vapour condenses on surfaces of the heat exchanging device. The air flow then returns back to the processing chamber. Condensed water is returned back to the bottom of the processing chamber via a condensed water outlet (not shown). The drying of the air is illustrated by two arrows in FIGS. 1-2. Depending on the temperature of the final rinse, the heat stored in the dishes and structural parts of the processing chamber might be insufficient to warm up the return air from the heat exchanger and sustain further evaporation of water (drying). Additional heating of the return air by the heat pump or other means is needed and implemented in such cases.

(13) The washer-dryer illustrated in FIG. 2 comprises a processing chamber 5 in the form of a rotatable drum into which the wash goods are loaded. Moreover, the washer-dryer comprises the same general parts as described above in relation with the dishwasher of FIG. 1. Accordingly, the described features and processes also apply to the washer-dryer according to FIG. 2.

(14) In FIG. 3 a dishwasher 2 is illustrated according to an embodiment of the invention. The dishwasher comprises a processing chamber 5 in which dish goods 10 such as plates, bowls, cutlery and the like are placed to be washed. In the washing procedure a wash liquid, normally water and a detergent are moved around in the processing chamber. A water tank 7 is arranged at a side of the processing chamber. Water in the tank is heated before it is introduced into the processing chamber 5. Water is introduced to the water tank 7 from a main water inlet 12. From the main water inlet, water may be distributed to the water tank and/or directly into the processing chamber, optionally via a softening device to reduce its hardness. An inlet valve 12a is provided to be able to control the distribution of inlet water. Warm water leaves the water tank 7 through a tank outlet 14. A tank outlet valve 14a is provided in a water pipe 16 providing water to the processing chamber. If necessary, the warm inlet water may be mixed with more water directly from the main water inlet 12. In the bottom of the processing chamber 5 a heater device 18 is arranged for heating water in the bottom of the process chamber. Depending on the type of wash program selected, extra heating of the water may be required as the heat pump alone might be insufficient to heat up the water in the tank 7 to the intended process temperature in the available time. For distribution of the water in the processing chamber at least one wash arm 22 is provided. Water or wash liquid is distributed to the wash arm 22 by a wash liquid pump 24. For emptying wash liquid or water from the processing chamber 5 a drain pump 26 is used. The drain pump 26 is arranged in the bottom of the processing chamber and is connected to a processing chamber outlet 28.

(15) As described with reference to FIGS. 1-2, the liquid in the heat reservoir 15 has been cooled by the evaporator 13 at the same time as the water in the water tank was heated by the condenser 11 during the working phase of the heat pump 9. In the embodiment shown in FIG. 3 the heat reservoir 15 is arranged outside the processing chamber 5. A cooling conduit 19 is arranged within the heat reservoir 15 and extends into the processing chamber 5. A partitioning wall 34 separates the cooling conduit 19 from the main part of the processing chamber. The cooling conduit 19 is thereby protected from the washing liquid circulating in the processing chamber during the washing phase.

(16) To start the drying phase, an air flow generating device 32, e.g. a fan, directs air and water vapour from the processing chamber towards the cooling circuit 19. By circulating a heat exchanging fluid in the cooling conduit with a pump 21 the outer surface of the cooling conduit is kept cool. The water vapour is directed towards the cooling conduit and water vapour condenses on the outer surface of the cooling conduit. The condense water runs off the cooling circuit and is drained back to the processing chamber through a condense water outlet 36. The pump 21 may be started at the same time as the air flow generating device 32 or just before.

(17) In FIG. 4 another embodiment of a dishwasher is shown. In this embodiment the heat reservoir 15 is arranged directly inside the processing chamber of the dishwasher. The heat reservoir is arranged at the back of the processing chamber 5 behind a partition wall 34. The partition wall separates the heat reservoir from the warm wash fluid in the interior of the processing chamber. The heat reservoir 15 itself has an outer condensing surface 15a. The outer surface may be of a metallic material providing excellent heat transfer properties. The condensing surface 15a, being in contact with the cooled or frozen liquid inside the reservoir, adapts the temperature of the cooled or frozen liquid. In the drying phase, the warm water vapour from the processing chamber is directed towards the heat reservoir in the same manner as described in relation to FIG. 3.

(18) FIG. 5 is a flow chart showing a method according to an embodiment. The method steps for using a heat pump in a household appliance will now be described with reference to the flow chart depicted in FIG. 5.

(19) 101. Heating water in a tank with the condenser

(20) 102. Cooling a liquid in a heat reservoir with the evaporator

(21) 103. Storing heat in the form of cooled or frozen liquid in the heat reservoir

(22) 104. Condensing water vapour from the processing chamber on a heat exchanging surface arranged in contact with the heat reservoir.

(23) According to the method, storing heat in the form of cooled or frozen liquid takes place in the heat reservoir at the same time as water in the water tank is being warmed by the condenser. In this way an efficient use of the heat pump may be obtained.

(24) By the step of condensing water vapour from the processing chamber humidity is removed from the air in the processing chamber and the goods therein are dried. The heat exchanging surface to condensate on may be available on a heat exchanging device being in connection with the heat reservoir. The heat exchanging surface to condensate on may alternatively be available on the heat reservoir itself.