DISHWASHER WITH DRYING ZONE OR DRYING TUNNEL AND HEAT PUMP DEVICE

Abstract

A dishwasher (1) comprises at least one drying zone (2) or at least one drying tunnel (2) for drying cleaned dishes (8), a fan (3) for generating an air circuit (4) within the at least one drying zone (2) or the at least one drying tunnel (2), and a heat pump device (5). The heat pump device (5) comprises a refrigeration circuit (50) in which a refrigerant circulates, an evaporator (51) for cooling and dehumidifying the air of the air circuit (4), and a condenser (53) for heating the air cooled and dehumidified by the evaporator (51). The dishwasher (1) is configured such that it directs the air heated by the condenser (53) over the dishes (8) to be dried and then feeds it at least partially or completely back to the evaporator (51).

Description

[0001] The present invention relates to a dishwasher with a drying zone or a drying tunnel and with a heat pump device.

[0002] In a drying zone (e.g., a conveyor dishwasher) or a drying tunnel (e.g., a pass-through dishwasher), air is circulated by a fan and directed over the dishes to be dried. The air absorbs moisture from the dishes and thus dries them.

[0003] Conventionally, the circulating air is heated by an electric heater to reduce the relative humidity before the air is passed over the dishes. The electrical power of the electric heater is drawn from the mains supply.

[0004] EP 3 073 884 B1 describes a conveyor dishwasher with a rinsing zone, a drying zone, and a heat pump system. The heat pump system comprises an evaporator for transferring the thermal energy of the exhaust air that has been or is to be removed from the conveyor dishwasher to a refrigerant of the heat pump system, a heat exchanger for transferring the thermal energy of the refrigerant to the rinsing liquid that is to be sprayed into the rinsing zone, and another heat exchanger for transferring the thermal energy of the refrigerant to the drying air in the drying zone.

[0005] WO 2018 / 202761 A1 describes a household appliance comprising a housing; a drying chamber arranged in the housing and in which the drying process is carried out; an air duct, the ends of which open into the drying chamber and through which the drying air is passed; and a heat pump in which the cooling cycle is carried out, wherein the heat pump comprises a compressor which enables the suction and pumping of the coolant, an evaporator which enables the removal of the moisture in the drying air in the air duct, and a condenser which enables the heating of the drying air.

[0006] DE 10 2014 219 457 A1 describes a dryer with a drying chamber for objects to be dried, a process air duct, a fan in the process air duct, a heat pump circuit in which a refrigerant circulates, comprising as components an evaporator, a condenser, a throttle, and a compressor. The evaporator, the condenser, and the auxiliary heater are each thermally coupled to the process air duct, and the auxiliary heater is thermally coupled to the heat pump circuit. The invention also relates to a method for operating this dryer.

[0007] EP 2 215 953 A1 describes a dishwasher comprising at least one pre-washing area equipped with means for pre-washing dishes, at least one washing area equipped with means for washing dishes, at least one rinsing area with means for rinsing dishes, and at least one drying area with means for drying dishes. These areas (12, 14, 16, 46) are arranged in series and are traversed by means for transporting dishes. The drying area comprises at least one dehumidifying device capable of dehumidifying the air directed by the drying means onto the dishes passing through the drying area. The drying area also comprises a plurality of closed channels, i.e.without any openings allowing air exchange with the outside air, capable of directing dry air from the dehumidification device to the dishes passing through such a drying area. The drying area can thus dry the dishes by blowing fully recycled dry air at high speed onto the dishes themselves.

[0008] It is an object of the present invention to provide a dishwasher with a drying zone or a drying tunnel and with a heat pump device in order to improve the efficiency and user-friendliness taking into account the desired applications.

[0009] The above object is achieved by a dishwasher according to claim 1. Claims 2 to 8 relate to particularly advantageous implementations of the dishwasher according to claim 1.

[0010] A dishwasher according to the invention can be, for example, a conveyor dishwasher or a pass-through dishwasher and can be used in particular for commercial applications.

[0011] The dishwasher includes at least one drying zone (e.g. in the case of a conveyor dishwasher) or at least one drying tunnel (e.g. in the case of a pass-through dishwasher) for drying cleaned items, in particular dishes.

[0012] The dishwasher further includes a fan or fan unit for generating an air circuit, steam circuit, and / or vapor circuit, in particular a drying air circuit. The circuit runs within, in particular entirely within or substantially within, the at least one drying zone or the at least one drying tunnel. The air circuit can, in particular, be a closed circuit within the at least one drying zone or the at least one drying tunnel.

[0013] The heat pump device includes a refrigeration circuit in which a refrigerant circulates or can circulate, in particular during an operating state of the dishwasher. The refrigeration circuit can include a pipe or hose that receives the refrigerant and in which the refrigerant can circulate. The refrigeration circuit can be a closed circuit. The refrigeration circuit can in particular be hermetically sealed. The heat pump device or the refrigeration circuit further includes an evaporator or an evaporator unit for cooling and dehumidifying the air of the air circuit. In particular, the evaporator can be configured to transfer heat from the air of the air circuit to the refrigerant, thereby cooling the air of the air circuit. Furthermore, the evaporator can be configured to remove condensate that forms when the air is cooled, thereby dehumidifying the air of the air circuit.The condensate can be drained away safely and without contact with the dishes. The heat pump device or the refrigeration circuit further includes a condenser or a condenser unit for heating the air cooled and dehumidified by the evaporator. In particular, the condenser can be configured to transfer heat from the refrigerant to the air in the air circuit, thereby heating the air in the air circuit. The heat pump device or the refrigeration circuit can also include a compressor and an expansion valve.

[0014] The dishwasher is further configured to direct the air heated by the condenser over the items to be dried, in particular such that the air comes into contact with the items to be dried and absorbs moisture from the items and is possibly further heated by the items. The dishwasher is further configured to subsequently feed the air at least partially or completely back to the evaporator, in particular such that the air remains at least partially or completely in the air circuit. The evaporator can then cool and dehumidify the air again, etc.

[0015] The dishwasher according to the invention enables particularly efficient and energy-saving drying of the dishes. In particular, the heat pump device not only heats the drying air in the drying zone or drying tunnel to reduce its relative humidity, but also first cools it with the evaporator and dehumidifies it before it is reheated by the condenser. This reduces the relative humidity of the drying air to a particularly low level, enabling very efficient drying of the dishes.

[0016] In addition, the heat pump device uses energy directly from the drying air or the condensation energy obtained when dehumidifying the drying air to warm or heat the drying air. This significantly increases the energy efficiency of the heat pump device. Compared to direct electrical heating of the drying air, e.g., using heating registers, three to five times the heating energy can be obtained from a single portion of electrical energy. The increased energy efficiency significantly reduces energy consumption. This makes the dishwasher particularly environmentally friendly and economical.

[0017] Furthermore, since the air circuit runs within the at least one drying zone or the at least one drying tunnel, the heat pump device can also be arranged at least partially or entirely within the at least one drying zone or the at least one drying tunnel. This enables a compact and cost-effective design of the heat pump device and thus of the dishwasher. The heat pump device can thus be designed to be self-sufficient or quasi-self-sufficient. Furthermore, the reduced pipe lengths of the heat pump device or the refrigeration circuit reduce the refrigerant charge of the heat pump device. Furthermore, simple pre-assembly, production and assembly of the heat pump device and simple integration of the heat pump device into the drying zone or the drying tunnel of the dishwasher are enabled, in particular because the refrigeration circuit has no interface to other zones of the dishwasher.Furthermore, the heat pump device leaves space in the drying zone or drying tunnel for other components such as drying fans, air ducts, etc.

[0018] Thus, the dishwasher according to the invention improves efficiency and user-friendliness while taking into account the desired applications.

[0019] In a preferred embodiment, the heat pump device or the refrigeration circuit is arranged within, in particular completely within or substantially within, the at least one drying zone or the at least one drying tunnel. The heat pump device or the refrigeration circuit can in particular be arranged and dimensioned such that it does not extend geometrically beyond the at least one drying zone, at least with respect to a transport direction of the washware through the dishwasher. In particular, the evaporator, the condenser, the refrigeration circuit, the compressor and / or the expansion valve can be arranged within or substantially within the at least one drying zone or the at least one drying tunnel. Particularly preferably, the dishwasher further comprises a control unit for controlling the heat pump device.The control unit may also be arranged within or substantially within the at least one drying zone or the at least one drying tunnel.

[0020] This enables a very compact and cost-effective design of the heat pump device and thus of the dishwasher. Furthermore, the refrigerant charge of the heat pump device or the refrigeration circuit is significantly reduced. Furthermore, this enables particularly simple pre-assembly, production, and assembly of the heat pump device, as well as particularly simple integration of the heat pump device into the drying zone or drying tunnel of the dishwasher. Furthermore, the heat pump device leaves sufficient space in the drying zone or drying tunnel for other components such as drying fans, air ducts, etc.

[0021] In a further preferred embodiment, the dishwasher includes at least one wash zone, in particular a pre-wash zone and / or a main wash zone and / or a final rinse zone, for receiving and cleaning the washware, which is subsequently to be dried by the drying zone or the drying tunnel. The at least one wash zone or all wash zones are arranged spatially separate from the at least one drying zone or the at least one drying tunnel. The heat pump device or the refrigeration circuit is arranged outside or substantially outside the at least one wash zone.

[0022] This enables a very compact and cost-effective design of the heat pump device, as well as particularly simple pre-assembly, production, and installation of the heat pump device into the dishwasher, since the refrigeration circuit has no interface with the at least one washing zone. Furthermore, this reduces the refrigerant charge of the heat pump device.

[0023] In a further preferred embodiment, the dishwasher includes at least one rinsing circuit in which a rinsing liquid circulates. The rinsing liquid can be used, in particular, for pre-rinsing, main rinsing, or post-rinsing the items to be washed during a dishwasher cycle. The refrigeration circuit and the at least one rinsing circuit are arranged spatially separate from one another.

[0024] In a further preferred embodiment, the heat pump has an efficiency of at least 300%, preferably at least 400%, particularly preferably at least 500%. This increases energy efficiency and thus reduces energy consumption. This makes the dishwasher particularly ecological and economical.

[0025] In a further preferred embodiment, the mass or weight of the refrigerant circulating in the refrigeration circuit is less than 200 grams, preferably less than 150 grams, and particularly preferably less than 100 grams. This reduces the cost of the dishwasher and increases safety. In particular, this reduces the safety-related effort, e.g., according to standard EN IEC 60335-2-40, particularly because with flammable refrigerants (A3 refrigerants), the amount of refrigerant has a direct impact on the required size of the installation space for the dishwasher.

[0026] In a further preferred embodiment, the refrigerant contains propane (R290). The refrigerant may also consist of or consist essentially of propane. Propane has a GWP (Global Warming Potential) value of 3 and is therefore particularly environmentally friendly. This increases the environmental friendliness of the dishwasher.

[0027] In a further preferred embodiment, the dishwasher further includes one or more electric heating registers for heating the air in the air circuit. This allows for an increase in the performance of the dishwasher when drying the dishes, while the overall efficiency of the dishwasher with the heat pump device according to the invention and the one or more electric heating registers is still higher than with purely electric heating, e.g., by means of electric heating registers.

[0028] According to the invention, the dishwasher is configured to draw in ambient air or room air from an area surrounding the dishwasher or the room in which the dishwasher is installed, in particular by means of an intake device of the dishwasher; to mix the ambient air and the air from the air circuit heated by the condenser to form an air mixture; and to direct the air mixture over the items to be dried and then feed it at least partially or completely to the evaporator. The portion of the air mixture that is not fed to the evaporator can be released into the area surrounding the dishwasher, in particular as exhaust air. This allows the amount of air circulating in the air circuit to be controlled in order to optimize the performance and efficiency of the heat pump when drying the items to be washed.In particular, the dishwasher can - in addition to the air in the air circuit - also extract energy from the ambient air to dry the dishes in order to further increase the drying performance.

[0029] According to the invention, the proportion of air from the air circuit to the air mixture is equal to the proportion of the air mixture supplied to the evaporator. Depending on the desired application, the proportion of air from the air circuit to the air mixture can be, for example, at least 25%, at least 50%, or at least 75%. Thus, the air volume in the air circuit remains constant, thus achieving a particularly stable and high drying performance and efficiency of the dishwasher.

[0030] These and other features and advantages of the invention will become clear from the accompanying drawing, which shows a particularly advantageous embodiment.

[0031] Fig. 1 shows a schematic overview of an embodiment of the dishwasher 1 according to the invention. The dishwasher 1 includes a drying zone 2 or a drying tunnel 2 for drying cleaned dishes 8, a fan 3 for generating an air circuit 4 within the drying zone 2 or the drying tunnel 2, and a heat pump device 5. The heat pump device 5 includes a refrigeration circuit 50 in which a refrigerant circulates, an evaporator 51 for cooling and dehumidifying the air of the air circuit 4, and a condenser 53 for heating the air cooled and dehumidified by the evaporator 51. The dishwasher 1 is configured such that it directs the air heated by the condenser 53 over the dishes 8 to be dried and then feeds it at least partially or completely back to the evaporator 51.

[0032] The refrigerant circulates in the refrigeration circuit 50 and, at low pressure in the evaporator 51, absorbs heat energy from the air in the air circuit 4, in particular the drying air, thereby evaporating and cooling the drying air. In the process, some of the water vapor contained in the drying air also condenses. The condensation energy released in this process is also transferred to the refrigerant via the evaporator 51. The condensate 6, which is created when the air cools, can be safely discharged from the evaporator 51 without contact with the items to be washed 8. The compressor 52 then draws in the gaseous refrigerant and compresses it to a higher pressure. In the process, the refrigerant heats up considerably and is cooled in the condenser 53, located downstream (from the refrigerant perspective) of the compressor 52, where it is condensed or liquefied again. The heat energy released is transferred to the drying air of the air circuit 4, which is heated in the process.The liquefied and cooled refrigerant is then expanded downstream of the condenser 53 by the electronic expansion valve 54 to a lower pressure, where it cools significantly and partially evaporates again. This mixture of still liquid and gaseous refrigerant is then fed back into the evaporator 51, and the process begins again.

[0033] In Fig. 1 further shows a transport direction 7 along which the items to be washed 8 can be transported during operation of the dishwasher 1 through the dishwasher 1, in particular from a dish inlet side to a dish outlet side of the dishwasher 1. The heat pump device 5 is arranged within the drying zone 2 or the drying tunnel 2. The heat pump device 5 and the refrigeration circuit 50 are arranged and dimensioned in particular such that they do not extend geometrically beyond the drying zone 2, in particular with respect to the transport direction 7. In addition to the Fig.1, the drying zone 2 may comprise further zones, in particular a pre-rinse zone, a main rinse zone, and / or a final rinse zone. In this case, the items to be washed 8 may be transported along the transport direction 7 first through the pre-rinse zone, main rinse zone, and final rinse zone, and then through the drying zone 2, in order to be first cleaned and then dried. The further zones may be arranged spatially separate from the drying zone 2 or the drying tunnel 2. The heat pump device 5 may be arranged outside the other zones, in particular such that the refrigeration circuit 50 has no interface with the other zones. List of reference symbols 1 dishwasher 2 drying zone, drying tunnel 3 fans 4 Air circuit 5 Heat pump device 50 Refrigeration circuit 51 evaporators 52 compressors 53 Condenser 54 Expansion valve 6 Condensate 7 Transport direction 8 Dishes, dishes

Claims

[1] Dishwasher (1), comprising: at least one drying zone (2) or at least one drying tunnel (2) for drying cleaned items (8); a fan (3) for generating an air circuit (4) within the at least one drying zone (2) or the at least one drying tunnel (2); and a heat pump device (5) comprising: - a refrigeration circuit (50) in which a refrigerant circulates; - an evaporator (51) for cooling and dehumidifying the air of the air circuit (4); and - a condenser (53) for heating the air cooled and dehumidified by the evaporator (51); wherein the dishwasher (1) is configured such that it directs the air heated by the condenser (53) over the items to be dried (8) and then feeds it at least partially or completely back to the evaporator (51); wherein the dishwasher (1) is further configured to: - sucks in ambient air from an area surrounding the dishwasher (1); - the ambient air and the air of the air circuit (4) heated by the condenser (53) are mixed to form an air mixture; and - the air mixture is passed over the items to be dried (8) and then fed at least partially or completely to the evaporator (51); and wherein the proportion of air of the air circuit (4) in the air mixture is equal to the proportion of the air mixture that is fed to the evaporator (51). [2] Dishwasher (1) according to claim 1, wherein the heat pump device (5) is arranged within the at least one drying zone (2) or the at least one drying tunnel (2). [3] Dishwasher (1) according to claim 1 or 2, which further comprises at least one rinsing zone for receiving and cleaning the items to be washed (8), wherein the at least one rinsing zone is arranged spatially separate from the at least one drying zone (2) or the at least one drying tunnel (2); wherein the refrigeration circuit (50) is arranged outside the at least one rinsing zone. [4] Dishwasher (1) according to one of the preceding claims, which further comprises at least one rinsing circuit in which a rinsing liquid circulates; wherein the refrigeration circuit (50) and the at least one rinsing circuit are arranged spatially separated from one another. [5] Dishwasher (1) according to one of the preceding claims, wherein the heat pump has an efficiency of at least 300%, preferably at least 400%, particularly preferably at least 500%. [6] Dishwasher (1) according to one of the preceding claims, wherein the mass of the refrigerant circulating in the refrigeration circuit (50) is less than 200 grams, preferably less than 150 grams, particularly preferably less than 100 grams. [7] Dishwasher (1) according to one of the preceding claims, wherein the refrigerant contains propane. [8] Dishwasher (1) according to one of the preceding claims, which further comprises one or more electric heating registers for heating the air of the air circuit (4).

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