Dishwasher with heat pump device and suction device for machine air and ambient air

Abstract

A dishwasher comprises: a washing zone for receiving items to be cleaned; a heat pump device comprising a refrigeration circuit in which a refrigerant circulates; an intake device configured to draw in machine air from an interior area of ​​the dishwasher and ambient air from an exterior area of ​​the dishwasher and to supply an air mixture of the machine air and the ambient air to the heat pump device; and a control unit; wherein the heat pump device comprises an evaporator configured to transfer heat from the air mixture to the refrigerant; (i) wherein the heat pump device comprises a high-pressure sensor for detecting a condensing pressure of the refrigerant;wherein the control unit is configured to control a volume flow rate of the air mixture supplied to the heat pump device based on the detected condensing pressure, and / or ii) wherein the heat pump device includes a low-pressure sensor for detecting an evaporation pressure of the refrigerant; wherein the control unit is configured to control a volume flow rate of the air mixture supplied to the heat pump device based on the detected evaporation pressure.;

Description

[0001] The present invention relates to a dishwasher with a heat pump device and a suction device for machine air and ambient air.

[0002] Such a dishwasher is known, for example, from DE 10 2013 111 670 B3. The dishwasher described therein is a programmable automatic dishwasher that has a wash zone for receiving dishes to be cleaned and includes a heat pump device configured to be supplied with air and / or vapors from the wash zone and / or air from the area surrounding the programmable automatic dishwasher.

[0003] It is an object of the present invention to provide a dishwasher with a heat pump device and a suction device for machine air and ambient air in order to improve the efficiency and user-friendliness taking into account the desired applications.

[0004] The above object is achieved by a dishwasher according to claim 1 and by a dishwasher according to claim 13. Claims 2 to 12 relate to particularly advantageous implementations of the dishwasher according to claim 1, and claims 14 to 16 relate to particularly advantageous implementations of the dishwasher according to claim 13.

[0005] 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.

[0006] The dishwasher includes a wash zone or wash chamber for holding items to be cleaned, such as dishes or cutlery. The wash zone can, for example, be a pre-wash zone, main wash zone, or final rinse zone, or contain at least one or all of these zones. The wash zone serves to clean the dishes in one wash cycle using a detergent or a rinsing liquid.

[0007] Furthermore, the dishwasher includes a heat pump device or heat pump comprising a refrigeration circuit or refrigeration circuit in which a refrigerant circulates or can circulate, particularly during an operating state of the dishwasher. The refrigeration circuit may include a pipe or hose that receives the refrigerant and in which the refrigerant can flow or circulate. The refrigeration circuit may, in particular, be a closed circuit.

[0008] The dishwasher further comprises an intake device configured to draw in machine air or machine exhaust air from an interior area of ​​the dishwasher and ambient air or room air from a surrounding area or installation space of the dishwasher, generate an air mixture from the machine air and the ambient air, and supply the air mixture to the heat pump device or an evaporator contained in the heat pump device. The intake device may, in particular, include an exhaust air fan, one or more air inlets in a dishwasher housing, and a system of air ducts, as described in more detail below.The suction device can in particular be configured such that it sucks in the machine air at a machine inlet area on a dish inlet side of the dishwasher or at a surrounding area of ​​the dishwasher near the machine inlet area or at a machine outlet area on a dish outlet side of the dishwasher or at a surrounding area of ​​the dishwasher near the machine outlet area. The suction device can further be configured such that it sucks in the machine air that is discharged from the interior area or from the washing zone to the machine inlet area or to the surrounding area near the machine inlet area or to the machine outlet area or to the surrounding area near the machine outlet area. The interior area of ​​the dishwasher can in particular include the machine inlet area, the washing zone (ora pre-wash zone, a main wash zone and / or a final rinse zone), a drying zone and / or the machine outlet area. The interior area can in particular be delimited by the dishwasher housing. The machine air can in particular be or contain air and / or vapors, wherein the vapors or steam or water vapor can arise during a wash cycle, in particular in the interior area or in the wash zone. The ambient air can be free of vapors or can contain vapors that have escaped from the dishwasher into the ambient area. The proportion of vapors in the ambient air can be smaller than the proportion of vapors in the machine air. The humidity of the ambient air can be lower than the humidity of the machine air. The temperature of the ambient air can be lower than the temperature of the machine air.

[0009] The dishwasher further comprises a controller or control unit or dishwasher control unit, which may include both hardware and software components and may be used to control various appliance functions of the dishwasher, as described in more detail below. The control unit may be at least partially integrated into various components of the dishwasher, e.g., the intake device or the exhaust air fan, or may be formed separately. The controller may operate in a preset mode and / or be programmable by a user of the dishwasher.

[0010] The heat pump device comprises an evaporator device or an evaporator or heat exchanger or heat transfer device configured to transfer heat from the air mixture to the refrigerant. The evaporator can be part of the refrigeration circuit through which the refrigerant is transported. The evaporator can extract heat from the air mixture and transfer the extracted heat to the refrigerant.

[0011] In a first alternative, the heat pump device further comprises a high-pressure sensor for detecting or sensing a condensation pressure of the refrigerant or a high-pressure-side refrigerant pressure that is equal to, corresponds to, or substantially corresponds to the condensation pressure. In this case, the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected condensation pressure.

[0012] In a second alternative, the heat pump device further comprises a low-pressure sensor for detecting or sensing an evaporation pressure of the refrigerant or a low-pressure-side refrigerant pressure that is equal to, corresponds to, or substantially corresponds to the evaporation pressure. In this case, the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected evaporation pressure.

[0013] The heat pump device may include both a high pressure sensor and a low pressure sensor as described above.

[0014] The dishwasher according to the invention enables a particularly high recovery of thermal energy contained in the machine air and the ambient air, which is transferred to the machine air and the ambient air by washing processes within the dishwasher, by the dishwasher itself, and by the washed items. Through the intake device, an air mixture of the machine air and the ambient air can be fed to the heat pump device. The heat pump device can extract heat from the air mixture and transfer the extracted heat to the coolant. The energy thus recovered can be returned to the washing processes, in particular to the washing liquid or to an intermediate fluid in an intermediate circuit. The resulting heat recovery significantly reduces the energy required to maintain the washing processes.A large part of the heat and moisture that was previously released into the machine air and ambient air by the rinsing processes, the dishwasher itself and the warm / moist dishes can be removed.

[0015] Due to the multitude of different operating, installation, and environmental conditions, as well as the various configuration options of the dishwasher, a multitude of possible operating points arise for the heat pump device, each of which should be operated with optimal performance and efficiency. This is achieved in particular by the high-pressure sensor and / or low-pressure sensor according to the invention, as well as the control unit.

[0016] For example, if a dry zone is present, the heat pump device can draw in significantly less room air / vapour mixture than is the case without a dry zone, as described in more detail below. If a dry zone is present, the temperature and moisture content upstream of the evaporator of the heat pump device can therefore be significantly lower than is the case without a dry zone. As a result, the evaporation pressure of the refrigerant in the evaporator, measured by a low-pressure sensor, and the evaporation temperature of the refrigerant are set at a low level. In this case, by increasing the volume flow, the amount of room air / vapour mixture pumped increases, so that more heat is supplied to the evaporator. This increases the evaporation pressure and evaporation temperature of the refrigerant in the evaporator, and both the performance and efficiency of the heat pump are increased.

[0017] Conversely, reducing the flow rate can prevent excessively high evaporation pressures or temperatures of the refrigerant from being reached, which could cause the heat pump device to operate outside its specified operating limits. Another positive effect is that reducing the flow rate also lowers the temperature of the exhaust air or machine exhaust air.

[0018] Furthermore, the condensation pressure measured by the high-pressure sensor can provide an indication of how far the rinsing fluid required for the rinsing process has already been heated, or whether further heating is required, and approximately how much. By controlling the volume flow based on the measured condensation pressure, a particularly efficient operation of the heat pump device, in particular a particularly efficient heating of the rinsing fluid by the heat pump device, can be achieved.

[0019] By means of each of the controls described in the first and second alternatives, as well as by linking and superimposing them according to their priority, the dishwasher can be adjusted so that the refrigeration circuit of the heat pump device is always operated in the range of optimum performance and optimum efficiency, depending on the configuration of the dishwasher and its operating, installation and ambient conditions.

[0020] Thus, the features of the dishwasher according to the invention increase the efficiency and user-friendliness of the dishwasher.

[0021] In a preferred embodiment, the heat pump device includes a low-pressure sensor for detecting an evaporation pressure of the refrigerant, and the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected evaporation pressure. If the detected evaporation pressure falls below a minimum evaporation pressure, the control unit is further configured to increase the volume flow, in particular to increase it until the detected evaporation pressure reaches or exceeds the minimum evaporation pressure, a first target evaporation pressure, or a maximum evaporation pressure.

[0022] This ensures that the measured evaporation pressure is set to a value that does not fall below the minimum evaporation pressure or to a value at which the performance and efficiency of the heat pump are optimal. This is particularly advantageous if a drying zone is present, the housing of which, for example, covers and seals an opening to a second intake area, as described below. In this case, the intake device draws in significantly less room air / vapour mixture than is the case without a drying zone. As a result, the evaporation pressure of the refrigerant in the evaporator, measured by the low-pressure sensor, and the evaporation temperature of the refrigerant are set at a low level. In this case, increasing the volume flow increases the amount of room air / vapour mixture pumped, so that more heat is supplied to the evaporator.This increases the evaporation pressure and temperature of the refrigerant in the evaporator, increasing both the performance and efficiency of the heat pump. This increases the efficiency and user-friendliness of the dishwasher.

[0023] In a further preferred embodiment, the heat pump device includes a low-pressure sensor for detecting an evaporation pressure of the refrigerant, and the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected evaporation pressure. If the detected evaporation pressure exceeds a maximum evaporation pressure, the control unit is further configured to reduce the volume flow, in particular to reduce it for as long or as much as necessary until the detected evaporation pressure reaches or falls below the maximum evaporation pressure or a second target evaporation pressure or a minimum evaporation pressure. The second target evaporation pressure can in particular be equal to the first target evaporation pressure.

[0024] This ensures that the detected evaporation pressure is set to a value that does not exceed the maximum evaporation pressure or to a value at which the performance and efficiency of the heat pump are optimal. This is particularly advantageous when there is no drying zone and the intake device draws in the room air / vapor mixture, for example, both at a first intake area on a dish inlet side and at a second intake area on a dish outlet side, as described in more detail below. In this case, the reduction in the volume flow ensures that the higher temperature and humidity upstream of the evaporator in this dishwasher configuration does not lead to high evaporation pressures or evaporation temperatures of the refrigerant, which would otherwise cause the heat pump device to operate outside its specified operating limits.If the evaporation pressure measured by the low-pressure sensor within the evaporator and the resulting evaporation temperature of the refrigerant increases due to the absence of a drying zone and / or corresponding operating, installation, and / or ambient conditions that result in a higher temperature / humidity below the evaporator, the described control system can reduce the flow rate until the evaporation pressure measured by the low-pressure sensor or the resulting evaporation temperature of the refrigerant again corresponds to a defined setpoint or a minimum value that must not be undercut. Another positive effect is that the aforementioned reduction in the speed and flow rate of the exhaust air fan also reduces the temperature of the exhaust air. This increases the efficiency and user-friendliness of the dishwasher.

[0025] In a further preferred embodiment, the heat pump device includes a low-pressure sensor for detecting an evaporation pressure of the refrigerant, and the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected evaporation pressure. The control unit is further configured to determine or calculate an evaporation temperature of the refrigerant based on the detected evaporation pressure of the refrigerant, in particular depending on the refrigerant used, and to control the volume flow based on the determined evaporation temperature.In particular, if the determined evaporation temperature falls below a minimum evaporation temperature, the control unit can be configured to increase the volume flow until the determined evaporation temperature reaches the minimum evaporation temperature, a first target evaporation temperature, or a maximum evaporation temperature. Alternatively or additionally, if the determined evaporation temperature exceeds a maximum evaporation temperature, the control unit can be configured to decrease the volume flow until the determined evaporation temperature reaches the maximum evaporation temperature, a second target evaporation temperature, or a minimum evaporation temperature.

[0026] This enables particularly precise and efficient control of the flow rate depending on the refrigerant used. This further increases the efficiency and user-friendliness of the dishwasher.

[0027] In a further preferred embodiment, the heat pump device includes a high-pressure sensor for detecting a condensation pressure of the refrigerant, and the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected condensation pressure. If the detected condensation pressure falls below a minimum condensation pressure, the control unit can be configured to increase the volume flow until the detected condensation pressure reaches or exceeds the minimum condensation pressure, a first target condensation pressure, or a maximum condensation pressure.Additionally or alternatively, if the detected condensing pressure exceeds a maximum condensing pressure, the control unit can be configured to reduce the volume flow until the detected condensing pressure reaches or falls below the maximum condensing pressure or a second target condensing pressure or a minimum condensing pressure. The second target condensing pressure can, in particular, be equal to the first target condensing pressure. Furthermore, the control unit can be configured to determine or calculate a condensing temperature of the refrigerant based on the detected condensing pressure of the refrigerant, in particular depending on the refrigerant used, and to control the volume flow based on the determined condensing temperature.In particular, if the determined condensing temperature falls below a minimum condensing temperature, the control unit can be configured to increase the volume flow until the determined condensing temperature reaches the minimum condensing temperature, a first target condensing temperature, or a maximum condensing temperature. Additionally or alternatively, if the determined condensing temperature exceeds a maximum condensing temperature, the control unit can be configured to decrease the volume flow until the determined condensing temperature reaches the maximum condensing temperature, a second target condensing temperature, or a minimum condensing temperature.

[0028] This is particularly advantageous because the condensation pressure in the heat pump's condenser, which is measured by a high-pressure sensor, can be an indication of how far the rinsing liquid required in a rinsing tank for the rinsing process has already been heated, or whether further heating is required and approximately to what extent. For example, if the condensation pressure measured by a high-pressure sensor and the condensation temperature determined from this depending on the refrigerant exceeds a defined target value or setpoint, preferably 75°C, the control unit can reduce the volume flow until a target value for the condensation temperature, preferably 75°C, is reached again. Using the options described above for controlling the volume flow based on the measured condensation pressure or setpoint, the control unit can reduce the volume flow based on the measured condensation pressure or setpoint.The determined condensation temperature thus allows for particularly efficient operation of the heat pump device, in particular, particularly efficient heating of the dishwashing liquid by the heat pump device. This further increases the efficiency and user-friendliness of the dishwasher.

[0029] Particularly preferably, the heat pump device comprises a low-pressure sensor for detecting an evaporation pressure of the refrigerant and a high-pressure sensor for detecting a condensation pressure of the refrigerant, and the control unit is configured to control a volume flow of the air mixture supplied to the heat pump device based on the detected evaporation pressure and the detected condensation pressure. If the detected condensation pressure exceeds a maximum condensation pressure and the detected evaporation pressure does not fall below a minimum evaporation pressure, the control unit can be further configured to reduce the volume flow until the detected condensation pressure reaches the maximum condensation pressure or a second target condensation pressure or a minimum condensation pressure, or until the detected evaporation pressure falls below the minimum evaporation pressure.

[0030] By additionally requiring that the measured evaporation pressure does not fall below a minimum evaporation pressure, it is possible, in particular, to ensure that the volume flow control based on the evaporation pressure of the refrigerant takes priority over the volume flow control based on the condensation pressure of the refrigerant. For example, if the condensation pressure measured by a high-pressure sensor and the condensation temperature determined from it depending on the refrigerant exceed a defined target value or setpoint, preferably 75°C, the control unit can reduce the volume flow until a target condensation temperature, preferably 75°C, is reached again.Since this reduction in volume flow also causes the refrigerant's evaporation pressure measured by the low-pressure sensor and the resulting refrigerant-dependent evaporation temperature to drop and possibly fall below a defined minimum value, the volume flow control is then limited to the target condensation temperature, and the volume flow is not reduced further. The volume flow can then be increased again until the defined minimum value of the refrigerant's evaporation temperature in the evaporator is reached again. In this case, controlling the volume flow to the refrigerant's evaporation temperature takes priority over controlling the volume flow to the refrigerant's condensation temperature.Conversely, however, it is also possible that controlling the volume flow to the condensing temperature of the refrigerant takes priority over controlling the volume flow to the evaporating temperature of the refrigerant.

[0031] By linking and superimposing the controls described above according to their desired priority, the control and consequently the volume flow of the air mixture supplied to the heat pump device can be adjusted so that the cooling circuit of the heat pump is always operated in the range of optimal performance and efficiency, depending on the configuration of the dishwasher, as well as its operating, installation and ambient conditions.

[0032] In a further preferred embodiment, the dishwasher is configured such that a drying zone can be mounted on or in the dishwasher or on a dishwasher housing or another part of the dishwasher, preferably detachably mounted and removed again. Furthermore, the control unit is configured such that a starting value for the volume flow is higher when the drying zone is mounted than when the drying zone is not mounted or is removed again. The drying zone can be a component of the dishwasher or a separate component that is mounted on an existing dishwasher. The starting value for the volume flow can be a value that the volume flow assumes at a starting time, wherein the starting time can be a time at which operation of the dishwasher or the heat pump device or a washing process of the dishwasher begins.

[0033] If a drying zone is present or installed, the temperature and humidity of the air mixture, for example, below the evaporator, are lower, as already described, than if no drying zone is present or installed. Thus, the different starting values ​​depending on the dishwasher's configuration, as described above, allow for faster and more efficient control, so that, in particular, the target values ​​for evaporation pressure or temperature and / or condensation pressure or temperature are reached more quickly.

[0034] In a further preferred embodiment, the intake device comprises an exhaust air fan with adjustable speed, and the control unit is configured to control the volume flow by regulating or controlling the speed of the exhaust air fan. The exhaust air fan can be arranged downstream of the evaporator with respect to a flow direction of the air mixture, in contrast to air inlets, which can be arranged upstream of the evaporator. Thus, air entering the dishwasher through the air inlets can first be transported towards the evaporator and thereby supplied to the heat pump device and then transported further towards the exhaust air fan and expelled from the dishwasher as exhaust air. The exhaust air fan can have a continuously variable speed.The control unit may be configured to increase the air flow by increasing the speed of the exhaust air fan and to decrease the air flow by decreasing the speed of the exhaust air fan.

[0035] The variable-speed exhaust air fan creates a particularly precise and cost-effective intake system. The continuously variable speed further increases the precision of the intake system's control.

[0036] The dishwasher preferably further comprises a fan housing and a fan cover. The fan housing is arranged in a height direction relative to the heat pump device (or relative to a heat pump housing of the heat pump device in which the refrigeration circuit is arranged) and is preferably fastened to the heat pump device (or to the heat pump housing). Furthermore, the fan housing is designed to accommodate the exhaust air fan. The fan cover is arranged to be linearly movable relative to the fan housing along a depth direction between a covering position for covering the exhaust air fan in the height direction and a removal position for removing the fan cover from the exhaust air fan, wherein the depth direction is perpendicular to the height direction. The height direction can be a z-direction. The depth direction can be a y-direction.The dishwasher may further comprise a transport device for transporting the items to be cleaned along a transport direction from a dish inlet side to a dish outlet side, wherein the transport direction may be an x-direction. The x-, y-, and z-directions may each be perpendicular to one another. The fan housing may comprise four side walls, of which two opposite side walls are formed parallel to the xz-plane and two opposite side walls are formed parallel to the yz-plane. The fan cover may run parallel to the xy-plane when in the covering position. The fan cover may be releasably fastened to the fan housing in the covering position, e.g., by means of screws.

[0037] Due to the overall height of the heat pump dishwasher with fan housing, the fan cover cannot be removed upwards, i.e., vertically, depending on the height of the installation room. However, with the configuration described above, the fan cover can be easily moved horizontally, i.e., along the depth direction, from the covering position to the removal position and thus removed. This makes the exhaust air fan easily accessible, and maintenance and cleaning work can be carried out quickly and easily. After maintenance and cleaning work is completed, the fan cover can be easily moved horizontally from the removal position to the covering position. This increases the user-friendliness of the dishwasher.

[0038] Particularly preferably, the fan housing comprises a guide element and a retaining element. The guide element extends in the depth direction and is designed to guide the fan cover between the covering position and the removal position. The retaining element is designed to be elastically deformable relative to the guide element, so that when the fan cover is in the covering position, the retaining element presses the fan cover against the guide element and thereby fixes the fan cover in the vertical direction. The guide element can in particular comprise one or two stop tabs. The retaining element can further comprise one or two front tabs or front-side sheet metal tabs.A gap can be formed between each front tab and a corresponding stop tab, through which the fan cover (in particular, a stiffening tab of one or two stiffening tabs of the fan cover) can be inserted. When moving between the removal position and the covering position, the fan cover can be held, guided, and pressed against the one or two stop tabs by the one or two front tabs.

[0039] This allows the fan cover to be moved back and forth between the removal and covering positions with ease, and it remains particularly stable in the covering position. This further enhances user-friendliness.

[0040] In a further preferred embodiment, the heat pump device comprises a high-pressure sensor for detecting a condensation pressure of the refrigerant, and the heat pump device comprises an expansion valve, in particular an electronic expansion valve. If the detected condensation pressure exceeds a maximum condensation pressure, the control unit is configured to close the expansion valve until the detected condensation pressure reaches or falls below the maximum condensation pressure, a second target condensation pressure, or a minimum condensation pressure.

[0041] This ensures that the measured condensing pressure is set to a value that does not exceed the maximum condensing pressure or to a value at which the heat pump's performance and efficiency are optimal. Closing the expansion valve in this case ensures that high condensing pressures or condensing temperatures of the refrigerant do not occur, which would otherwise cause the heat pump device to operate outside its specified operating limits.

[0042] For example, if the heating requirement of the rinsing liquid contained in the rinsing tank is lower and the temperature of the rinsing liquid is therefore correspondingly high near a defined target temperature, the condensation pressure and the resulting condensation temperature of the refrigerant in the condenser can also increase and may possibly exceed the specified operating limits of a compressor in the heat pump device. This and any resulting undesired premature shutdown of the heat pump can be prevented by controlling the expansion valve as described above. This measure allows the heat pump and thus the energy recovery from the room air / vapour mixture to remain active for a certain period of time even at a higher temperature of the rinsing liquid in the rinsing tank. A necessary shutdown of the heat pump can thus be delayed.The room air / vapour mixture extracted by the air system during the flushing process can thus continue to be cooled and dehumidified, which in turn has a positive effect on the climatic conditions in the installation room.

[0043] In a further preferred embodiment, the heat pump device comprises a low-pressure sensor for detecting an evaporation pressure of the refrigerant and a high-pressure sensor for detecting a condensation pressure of the refrigerant. The control unit is configured to determine a pressure difference between the detected condensation pressure and the detected evaporation pressure and, if the pressure difference does not exceed a predefined minimum differential pressure within a predetermined time interval from a start time of the heat pump device or a compressor of the heat pump device, to output a signal. The start time can be a time at which operation of the heat pump device or the compressor begins. The signal can be a warning signal to a user or can cause the dishwasher to output a warning to a user, for example, via a display of the dishwasher.Alternatively or additionally, the signal emitted may cause the dishwasher or heat pump device to be automatically switched off or deactivated.

[0044] The control system can therefore determine any incorrect electrical rotating field of the heat pump device using the calculated pressure difference. In particular, a correct electrical rotating field and, consequently, the correct direction of rotation of a compressor in the heat pump device is necessary for the heat pump device to function, since otherwise the compressor cannot pump any refrigerant and could suffer irreparable damage. With a correct rotating field, the compressor exceeds the predetermined minimum differential pressure within the predetermined time interval. If the predetermined minimum pressure difference is not exceeded within the predetermined time, this can be concluded that the rotating field at the compressor is incorrect. In this case, the control unit can deactivate the compressor and display a corresponding error message to the operator, who can then request that the error be rectified.This increases the safety and user-friendliness of the dishwasher.

[0045] Another dishwasher according to the invention is a conveyor dishwasher that has a dish inlet side and a dish outlet side. The other dishwasher according to the invention can include any feature and any combination of features described above in connection with the dishwasher according to the invention.

[0046] The conveyor dishwasher comprises a dishwasher housing having a dish inlet opening on the dish inlet side for introducing items to be cleaned, such as dishes or cutlery, into the dishwasher and a dish outlet opening on the dish outlet side for discharging the cleaned items from the dishwasher. The dishwasher housing may, in particular, comprise the rinsing zone and the drying zone, which are described further below.

[0047] The dishwasher includes at least one wash zone or wash chamber for cleaning the dishes. The at least one wash zone can be designed as described above in connection with the dishwasher according to the invention.

[0048] The dishwasher further includes at least one drying zone or drying chamber for drying the cleaned dishes, wherein the at least one drying zone is formed separately from the at least one rinsing zone. Preferably, the drying zone is arranged in a transport direction relative to the rinsing zone, so that the dishes can first be cleaned in the rinsing zone and then transported by a transport device from the rinsing zone to the drying zone along the transport direction for drying in the drying zone. The transport direction and the transport device are described in more detail below.

[0049] The dishwasher further includes a heat pump device or heat pump comprising a refrigeration circuit or refrigeration circuit in which a refrigerant circulates or can circulate. The heat pump device can be designed as described above in connection with the dishwasher according to the invention.

[0050] The dishwasher further includes an intake device configured to intake machine air or machine exhaust air from an interior region of the dishwasher and first ambient air or first room air from a first ambient region of the dishwasher located on the dish inlet side of the dishwasher, and to supply an air mixture of the machine air and the first ambient air to the heat pump device or to an evaporator contained in the heat pump device. The intake device may, in particular, be configured to intake the machine air at a machine inlet region on the dish inlet side or at a surrounding region of the dishwasher near the machine inlet region, or at a machine outlet region on the dish outlet side or at a surrounding region of the dishwasher near the machine outlet region.The intake device can further be configured to intake the machine air that is discharged from the interior area or from the washing zone to the machine inlet area or to the surrounding area near the machine inlet area or to the machine outlet area or to the surrounding area near the machine outlet area. The interior area of ​​the dishwasher can in particular comprise the machine inlet area, the at least one washing zone (or a pre-wash zone, a main wash zone and / or a final rinse zone), the at least one drying zone and / or the machine outlet area. The interior area can in particular be delimited by a dishwasher housing. Furthermore, the intake device is configured to intake second ambient air or second room air from a second surrounding area of ​​the heat pump device and supply it to the heat pump device or the evaporator.The suction device can further be designed as described above in connection with the dishwasher according to the invention. The dishwasher housing can have one or more air inlet openings on the dish inlet side for admitting the first ambient air into the dishwasher. The machine air can be of the type described above in connection with the dishwasher according to the invention. The first and second ambient air can each be of the type described above in connection with the dishwasher according to the invention.

[0051] The heat pump device further comprises an evaporator device or an evaporator or heat exchanger or heat transfer device configured to transfer heat from the air mixture to the refrigerant and configured to transfer heat from the second ambient air to the refrigerant. The evaporator can be part of the refrigeration circuit through which the refrigerant is transported. The evaporator can extract heat from the air mixture and transfer the extracted heat to the refrigerant. The evaporator can extract heat from the second ambient air and transfer the extracted heat to the refrigerant.

[0052] The further dishwasher according to the invention enables a particularly high recovery of heat energy contained in the machine air and the ambient air, which is transferred to the machine air and the ambient air by rinsing processes within the dishwasher, by the dishwasher itself and by the rinsed items to be cleaned.

[0053] Through the intake device, an air mixture consisting of the machine air and the first ambient air can be fed to the heat pump device. The heat pump device can extract heat from the air mixture and transfer the extracted heat to the coolant. The energy thus recovered can be returned to the dishwashing processes, particularly to the dishwashing liquid. The resulting heat recovery significantly reduces the energy required to maintain the dishwashing processes. A large portion of the heat and moisture previously released by the dishwashing processes, the dishwasher itself, and the warm / damp dishes can be extracted from the machine air and the first ambient air.

[0054] Since the further dishwasher according to the invention includes a drying zone, however, less room air / vapour mixture can be sucked in by the heat pump device than would be the case without a drying zone. In particular, the drying zone eliminates the need for a second intake area on the dish outlet side, since, for example, a housing of the drying zone can cover and seal an opening to the second intake area. The intake device can thus only suck in room air / vapour mixture from a first intake area on the dish inlet side, which causes increased pressure losses in the system of air pipes through which the room air / vapour mixture flows from the first intake area.Since the existing drying zone means that the energy available to the evaporator for cooling / heat recovery from the room air / vapour mixture is significantly lower than if there were no drying zone and the air were extracted through two intake areas on the dish inlet side and the dish outlet side, more room air / vapour mixture must be sucked in by the intake device in order to still generate an acceptable heating output from the heat pump. Thus, the presence of the drying zone brings together two problems that need to be solved: Firstly, the room air / vapour mixture would have to be sucked in entirely via the system of air ducts from the first intake area, and secondly, a higher volume flow would have to be transported through these air ducts. Both of these would result in a high pressure loss in the air ducts that would have to be overcome, which would require a higher-performance intake device.

[0055] However, these problems are solved according to the invention in that the intake device is configured such that it draws in second ambient air from a second ambient region of the heat pump device and supplies it to the heat pump device, and in that the evaporator is configured to transfer heat from the second ambient air to the refrigerant. As a result, the quantity of room air / vapour mixture to be drawn in via the air pipes from the first intake region is reduced to the level that would be the case without a drying zone, and the heat pump device still receives additional room air as a heat source. The pressure loss in the air system that has to be overcome by the intake device thus remains at a similar level to that which would be without a drying zone. This increases the efficiency and user-friendliness of the dishwasher.

[0056] In a preferred embodiment, the heat pump housing comprises one or more heat pump housing openings for admitting the third ambient air into the dishwasher. This has the advantage that the intake device can very efficiently draw in the second ambient air from the second ambient area of ​​the heat pump device and supply it to the heat pump device. This increases the efficiency and user-friendliness of the dishwasher.

[0057] In a further preferred embodiment, the dishwasher comprises a transport device for transporting the items to be cleaned along a transport direction from the dish inlet side to the dish outlet side. The evaporator extends or has an extension over an extension area in or along the transport direction. Furthermore, at least one or more heat pump housing openings of the one or more heat pump housing openings are designed and positioned such that they lie at least partially or completely within the extension area of ​​the evaporator in the transport direction or at least partially overlap with the extension area of ​​the evaporator in the transport direction. This has the advantage that the second ambient air can flow along a flow path from the one or more heat pump housing openings to the evaporator, which flow path is perpendicular or substantially perpendicular to the transport direction (iealong the y-direction and / or the z-direction). Thus, the intake device can very efficiently draw in the second ambient air from the second ambient area and supply it to the evaporator, thus increasing efficiency and user-friendliness.

[0058] In a further preferred embodiment, the heat pump device comprises a filter unit, in particular a grease filter, for filtering the second ambient air, wherein the intake device is configured to supply the filtered second ambient air to the evaporator. This allows, for example, dirt or grease particles to be filtered out of the second ambient air so that they do not penetrate the heat pump device. This prevents damage to or a reduction in the efficiency of the heat pump device. The filter unit is preferably arranged within the heat pump housing, thereby resulting in a particularly compact dishwasher.

[0059] These and other features and advantages of the invention will become clear from the accompanying drawings, which show particularly advantageous embodiments. They show: Fig. 1 a schematic overall overview of an embodiment of a dishwasher according to the invention; Fig. 2 the refrigeration circuit of the dishwasher Fig. 1; Fig. 3 the intermediate circuit of the dishwasher Fig. 1; Fig. 4 the lye circuit of the dishwasher Fig. 1; Fig. 5 the air system with drying zone of the dishwasher Fig. 1; Fig. 6A the fan housing and the fan cover when the fan cover is in the cover position; Fig. 6B the fan housing and the fan cover when the fan cover is in the removal position; Fig. 6C an enlarged section of Fig. 6B; and Fig. 6D another enlarged section of Fig. 6B.

[0060] The following description refers to a conveyor dishwasher 2 as an example of a dishwasher 2; however, the invention is not limited to a conveyor dishwasher 2, but relates generally to a dishwasher 2, which can also be, for example, a pass-through dishwasher. Likewise described below are a heat pump 1 as an example of a heat pump device 1, vapors 3 as an example of machine air 3, room air 4 as an example of ambient air 4, dishes 5 as an example of items to be washed 5, room air / vapor mixture 43 as an example of an air mixture 43, an installation room 45 as an example of an ambient area 45, a grease filter 46 as an example of a filter unit 46, an intermediate circuit temperature sensor 47 as an example of a temperature sensor 47, and a pre-wash zone 51 and / or a main wash zone 52 and / or a final rinse zone 31 as examples of a wash zone 51, 52, 31.Furthermore, additional room air intake 38 refers to a system comprising or consisting of one or more heat pump housing openings and an integrated filter unit 46, e.g., an integrated grease filter 46. Furthermore, the terms machine air 3 and machine exhaust air 3, refrigeration circuit 6 and refrigeration circuit 6 are used synonymously, as are intermediate circuit 17 and secondary intermediate circuit 17, intermediate fluid 18 and secondary fluid 18, lye circuit 25 and lye circuit 25, lye circuit pump 27 and tank circulation pump 27, as well as control unit 32 and dishwasher control unit 32.

[0061] Fig. 1 shows a schematic overall overview of an embodiment of a dishwasher 2 according to the invention; Fig. 2 shows in particular a refrigeration circuit 6 of the dishwasher 2 from Fig. 1; Fig. 3 shows in particular an intermediate circuit 17 of the dishwasher 2 from Fig. 1; Fig. 4 shows in particular a lye circuit 25 of the dishwasher 2 from Fig. 1; and Fig. 5 shows in particular an air system with drying zone 53 of the dishwasher 2 from Fig. 1.

[0062] In particular, Fig. 1 to 5 each show a commercial conveyor dishwasher 2 for the high recovery of heat energy contained in the machine exhaust air 3 and the room air 4 surrounding the dishwasher 2, which heat energy is transferred to the machine exhaust air 3 and room air 4 by the washing processes within the dishwasher 2, by the dishwasher 2 itself, and by the washed dishes 5. By high heat recovery from the machine exhaust air 3 and room air 4 and transferring this energy back to the washing processes, the energy required to maintain the washing processes is significantly reduced. In this way, a large portion of the heat and moisture that was previously transferred to the machine exhaust air 3 and room air 4 by the washing processes, the dishwasher 2 itself, and the warm / moist dishes 5 is removed from the machine exhaust air 3 and room air 4.

[0063] The heat pump 1 is installed in a heat pump housing 15 and contains a refrigeration circuit 6, consisting of an evaporator 7, a compressor 8, a series circuit of a condenser 9 and a subcooler 10, an electronic expansion valve 11, and the pipes 12 of different nominal diameters connecting the aforementioned components. The refrigeration circuit 6 further contains a high-pressure sensor 13 for detecting the high-pressure refrigerant pressure, which corresponds or substantially corresponds to the condensation pressure of the refrigerant, a low-pressure sensor 14 for detecting the low-pressure refrigerant pressure, which corresponds or substantially corresponds to the evaporation pressure of the refrigerant, and other components.

[0064] A refrigerant 16 circulates in the refrigeration circuit 6. At low pressure in the evaporator 7, it absorbs thermal energy from the machine exhaust air 3, thereby evaporating and cooling the machine exhaust air 3. In the process, some of the water vapor contained in the machine exhaust air 3 also condenses. This condensation energy is also transferred to the refrigerant 16 via the evaporator 7. The compressor 8 then draws in the gaseous refrigerant 16 and compresses it to a higher pressure. In the process, the refrigerant 16 heats up considerably and is cooled in the condenser 9 located downstream (from the refrigerant perspective) of the compressor 8, where it is then condensed / liquefied again. The thermal energy released is transferred to a secondary fluid 18 circulating in a secondary intermediate circuit 17, which is heated in the process.The completely or at least partially liquefied refrigerant 16 is then further cooled / subcooled in the subcooler 10, which is located downstream of the condenser 9 from the refrigerant perspective, or the remaining gaseous refrigerant 16 is first liquefied / condensed. The heat energy released in this process is transferred to a post-rinse liquid 93 located in the post-rinse system 94, which is sucked in from a water network separator / air gap 50 by a post-rinse pump 49 and then conveyed to the subcooler 10, preheated therein, and subsequently heated to a desired post-rinse temperature in an electrically heated boiler 48. The completely liquefied and subcooled refrigerant 16 is now expanded back to a lower pressure by the electronic expansion valve 11 downstream of the subcooler 10 from the refrigerant perspective, during which it cools down significantly and partially evaporates again.This mixture of still liquid and gaseous refrigerant 16 is then fed back into the evaporator 7 and the process begins again.

[0065] The evaporator 7 of the heat pump 1 is part of the air system 33, which, in addition to the evaporator 7, essentially consists of a first intake area 34 on the dish inlet side 35, a second intake area on the dish outlet side 37 or, depending on the dishwasher variant, an additional room air intake 38, a speed-adjustable exhaust air fan 39, and a system of air ducts 40. The mixture of room air 4 and vapors 3 generated during the washing process, the so-called room air / vapor mixture 43, sucked in by the exhaust air fan 39 at the first intake area 34 and second intake area or the additional room air intake 38, is guided through the system of air ducts 40 to the heat pump housing 15 and cooled and dehumidified by heat exchange with the refrigerant 16 by means of the evaporator 7.The exhaust air fan 39 is housed downstream of the evaporator 7, from the perspective of the room air / vapor mixture 43, in a separate fan housing 42 mounted above the heat pump housing 15. The cooled and dehumidified room air / vapor mixture 43 exits through a plurality of openings 44 in the fan housing 42 into the installation space 45 surrounding the dishwasher 2. To separate dirt and droplets and protect the air system 33 from coarser contaminants, a grease filter 46 is integrated in each of the first intake area 34, the second intake area, and the additional room air intake 38.

[0066] The secondary intermediate circuit 17, whose secondary fluid 18 was heated by the condenser 9, is a circuit open to the atmosphere of the installation room of the commercial conveyor dishwasher 2 or the dishwasher interior 20. The secondary intermediate circuit 17 consists of a reservoir 21 to ensure a certain water level for the intermediate circuit pump 22, which is arranged downstream from the perspective of the secondary fluid 18 and conveys the secondary fluid 18 to the condenser 9, an intermediate circuit temperature sensor 47 at the outlet of the condenser 9, the coaxial heat exchanger 23, which transfers the thermal energy contained in the secondary fluid 18 after its heating in the condenser 9 to a rinsing liquid 24 and represents a system separation from the lye circuit 25, as well as the various hose connections between the aforementioned components (not described in detail).The secondary intermediate circuit 17 is filled with rinse liquid 93 through an intermediate circuit filling valve 29 connected to the rinse system 94 via hoses until the secondary intermediate circuit 17 is completely filled and overflows into the rinse zone 31 via an overflow hose 30. This filling process is activated by a dishwasher control unit 32 and deactivated again after the filling process is completed.

[0067] The aforementioned lye circuit 25 serves to suck in the washing liquid 24 required for the washing process in a first main washing zone 52 located downstream of an optionally present pre-wash zone 51 in the dish transport direction and mixed with appropriate washing chemicals and dirt particles rinsed off the dishes 5 from a washing tank 26 and to convey it by means of a tank circulation pump 27 to the coaxial heat exchanger 23, in which the washing liquid 24 is heated by the thermal energy contained in the secondary fluid 18. The washing liquid 24 then flows back into the washing tank 26. The coaxial heat exchanger 23, used for system separation, ensures that the washing liquid 24 loaded with washing chemicals and dirt particles does not come into contact with the secondary fluid 18, thus protecting the condenser 9 of the heat pump 1.

[0068] As particularly in Fig. 1, Fig. 4 and Fig. As can be seen in Figure 5, a dishwasher according to an embodiment of the present invention is a conveyor dishwasher 2 having a dish inlet side 35 and a dish outlet side 37, the conveyor dishwasher 2 comprising: a dishwasher cabinet having a dish inlet opening on the dish inlet side 35 for admitting dishes 5 to be cleaned into the dishwasher 2 and a dish outlet opening on the dish outlet side 37 for discharging the cleaned dishes 5 from the dishwasher 2; a pre-wash zone 51, main wash zone 52, and final wash zone 31, each for cleaning the dishes 5; a drying zone 53 for drying the cleaned dishes 5, the drying zone 53 being formed separately from the wash zones 51, 52, 31; a heat pump device 1 having a refrigeration circuit 6 in which a refrigerant 16 circulates; and a suction device 34, 38, 39 configured tothat it draws in machine air 3 from an interior area of ​​the dishwasher 2 and first ambient air from a first ambient area on the dish inlet side 35 of the dishwasher 2 and supplies an air mixture of the machine air and the first ambient air to the heat pump device 1, and that it draws in second ambient air from a second ambient area of ​​the heat pump device 1 and supplies it to the heat pump device 1; wherein in particular the suction device 34, 38, 39 is configured such that it draws in the machine air at a machine inlet area 35 on the dish inlet side of the dishwasher 2; wherein the heat pump device 1 comprises an evaporator 7,which is configured to transfer heat from the air mixture 43 to the refrigerant and is configured to transfer heat from the second ambient air to the refrigerant. The heat pump housing 15 can have one or more heat pump housing openings for admitting the second ambient air into the dishwasher 2. The conveyor dishwasher 2 can comprise a transport device 95 for transporting the dishes to be cleaned along a transport direction from the dish inlet side 35 to the dish outlet side 37, wherein the evaporator 7 extends along the transport direction and wherein the one or more heat pump housing openings at least partially overlap with the extension area of ​​the evaporator 7 in the transport direction. The heat pump device 1 can comprise a filter unit 46 for filtering the second ambient air, wherein the intake device 34, 38, 39 is configuredthat it supplies the filtered second ambient air to the evaporator 7, wherein the filter unit 46 is arranged within the heat pump housing 15.

[0069] In other words, the dishwasher 2 can contain an additional room air intake 38 with an integrated grease filter 46.

[0070] Depending on the dishwasher configuration, in particular depending on whether a drying zone 53 is present or not, the air system 33 of the commercial conveyor dishwasher 2 extracts the vapors 3 generated during the washing process either only by means of a first suction area 34 on the dish inlet side 35 or additionally by means of a second suction area on the dish outlet side 37.

[0071] If no drying zone 53 is present, the vapors 3 are extracted together with the room air 4 surrounding the dishwasher 2 by means of a first suction area 34 on the dish inlet side 35 and additionally by means of a second suction area on the dish outlet side 37. The room air / vapor mixture 43 formed in the two suction areas 34 is freed of water droplets and dirt particles via an integrated grease filter 46 in each suction area 34 and is guided via a system of air pipes 40 from the first suction area 34 into the area below the evaporator 7. The room air / vapor mixture 43 formed in the second suction area is also guided via an opening between the second suction area and the heat pump housing 15 into the area below the evaporator 7 and mixed there with the room air / vapor mixture 43 from the first suction area 34.

[0072] The room air / vapour mixture 43 is then cooled and dehumidified by heat exchange with the refrigerant 16 by means of the evaporator 7.

[0073] However, if the dishwasher 2 contains a drying zone 53, the second intake area on the dish outlet side 37 is omitted, since the housing of the drying zone 53 covers and seals the opening to the second intake area. In this case, the air system 33 of the heat pump 1 can only draw in the room air / vapor mixture 43 from the first intake area 34 on the dish inlet side 35 via the system of air pipes 40, which causes significantly increased pressure losses in the system of air pipes 40. Since, in the case of an existing drying zone 53, the energy available to the evaporator 7 for cooling / heat recovery from the room air / vapour mixture 43 is significantly lower than if there were no drying zone 53 and suction were effected at both suction areas 34, more room air / vapour mixture 43 must also be sucked in by the exhaust air fan 39 in order to still be able to generate an acceptable heating output of the heat pump 1.Thus, two factors come together: Firstly, if a drying zone 53 is present, the room air / vapour mixture would have to be completely drawn in via the system of air ducts 40, and secondly, a higher volume flow would have to be transported through the air ducts 40. Both would result in a high pressure loss to be overcome in the air ducts 40, which would require an exhaust air fan 39 with higher power.

[0074] According to one aspect of the present invention, in the case of a drying zone 53, in addition to the first intake area 34 on the dish inlet side 35, room air 4 is sucked in from the installation space 45 of the dishwasher by means of an additional room air intake 38 with integrated grease filter 46, which is positioned in the heat pump housing 15 below the evaporator 7. As a result, the amount of room air / vapor mixture to be sucked in via the system of air pipes 40 is reduced to the level that would be the case without the drying zone 53, and the heat pump 1 still receives additional room air 4 as a heat source below the evaporator 7. The pressure loss in the air system 33 that must be overcome by the exhaust air fan 39 remains at a similar level both with and without the drying zone 53.

[0075] As particularly in Fig. 1, Fig. 4 and Fig. 5, a dishwasher according to an embodiment of the present invention comprises: a washing zone 52 for receiving items 5 to be cleaned; a heat pump device 1 comprising a refrigeration circuit 6 in which a refrigerant 16 circulates; an intake device 34, 38, 39 configured to intake machine air 3 from an interior region of the dishwasher 2 and ambient air from an ambient region of the dishwasher 2 and to supply an air mixture 43 of the machine air 3 and the ambient air to the heat pump device 1; and a control unit 32; wherein the heat pump device 1 comprises an evaporator 7 configured to transfer heat from the air mixture 43 to the refrigerant 16; i) wherein the heat pump device 1 comprises a high-pressure sensor 13 for detecting a condensation pressure of the refrigerant 16; wherein the control unit 32 is configuredthat it controls a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected condensation pressure, and / or ii) wherein the heat pump device 1 comprises a low-pressure sensor 14 for detecting an evaporation pressure of the refrigerant 16; wherein the control unit 32 is configured to control a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected evaporation pressure. The heat pump device 1 may comprise a low-pressure sensor 14 for detecting an evaporation pressure of the refrigerant 16; wherein the control unit 32 is configured to control a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected evaporation pressure; wherein, if the detected evaporation pressure falls below a minimum evaporation pressure, the control unit 32 is configured to increase the volume flow,until the detected evaporation pressure reaches the minimum evaporation pressure or a first target evaporation pressure or a maximum evaporation pressure. The heat pump device 1 may comprise a low-pressure sensor 14 for detecting an evaporation pressure of the refrigerant 16; wherein the control unit 32 is configured to control a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected evaporation pressure; wherein, if the detected evaporation pressure exceeds a maximum evaporation pressure, the control unit 32 is configured to reduce the volume flow until the detected evaporation pressure reaches the maximum evaporation pressure or a second target evaporation pressure or a minimum evaporation pressure. The heat pump device 1 may comprise a low-pressure sensor 14 for detecting an evaporation pressure of the refrigerant 16; wherein the control unit 32 is configuredthat it controls a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected evaporation pressure; wherein the control unit 32 is configured to determine an evaporation temperature of the refrigerant 16 based on the detected evaporation pressure of the refrigerant 16 and to control the volume flow based on the determined evaporation temperature. The heat pump device 1 can comprise a high-pressure sensor 13 for detecting a condensation pressure of the refrigerant 16; wherein the control unit 32 is configured to control a volume flow of the air mixture 43 supplied to the heat pump device 1 based on the detected condensation pressure; i) wherein, if the detected condensation pressure falls below a minimum condensation pressure, the control unit 32 is configured to increase the volume flow,until the detected condensing pressure reaches the minimum condensing pressure or a first target condensing pressure or a maximum condensing pressure, and / or ii) wherein, if the detected condensing pressure exceeds a maximum condensing pressure, the control unit 32 is configured to reduce the volume flow until the detected condensing pressure reaches the maximum condensing pressure or a second target condensing pressure or a minimum condensing pressure. The control unit 32 can be configured to determine a condensing temperature of the refrigerant 16 based on the detected condensing pressure of the refrigerant 16 and to control the volume flow based on the determined condensing temperature. The dishwasher 2 can be configured such that a drying zone 53 can be mounted on or in the dishwasher 2; wherein the control unit 32 is configured such thatthat a starting value for the volume flow is higher when the drying zone 53 is mounted on or in the dishwasher 2 than when the drying zone 53 is not mounted on or in the dishwasher 2. The intake device 34, 38, 39 may comprise an exhaust air fan 39 with adjustable speed; wherein the control unit 32 is configured to control the volume flow by regulating the speed of the exhaust air fan 39.

[0076] In other words, the dishwasher 2 can comprise an exhaust air fan 39 with a control for optimal operation of the heat pump 1.

[0077] Due to the multitude of different operating, installation and environmental conditions of the commercial conveyor dishwasher 2, as well as different configuration options of the dishwasher 2, there are also a multitude of possible operating points for the heat pump 1, in each of which it should be operated with optimal performance and efficiency.

[0078] If a drying zone 53 is present, the heat pump draws in significantly less room air / vapour mixture than is the case without a drying zone 53. If a drying zone 53 is present, the temperature and humidity content upstream of the evaporator 7 of the heat pump 1 are therefore significantly lower than if a drying zone 53 is present. To compensate for this difference, an additional room air intake 38 can be used, as already described, which can supply additional room air 4 and thus energy from it to the evaporator 7 of the heat pump 1. Nevertheless, if a drying zone 53 is present on the dishwasher 2, the amount of heat available to the heat pump 1 at the evaporator 7 can be lower than if there is no drying zone 53 and then the room air / vapour mixture 43 is drawn in at the second intake area in addition to the first intake area 34.

[0079] According to one aspect of the present invention, the exhaust air fan 39 can compensate for this difference by continuously increasing or decreasing its speed through a suitable control, whereby the volume flow of room air / vapour mixture 43 conveyed by it through the air system 33 increases or decreases accordingly.

[0080] If a drying zone 53 is present, only a room air / vapour mixture 43 is sucked in at the first intake area 34, and additional room air 4 is sucked in at the additional room air intake 38 and mixed below the evaporator 7. Due to the low proportion of room air / vapour mixture 43, the temperature and humidity content upstream of the evaporator 7 are comparatively low, whereby the evaporation pressure of the refrigerant 16 in the evaporator 7, measured by the low-pressure sensor 14, and the evaporation temperature of the refrigerant 16 determined therefrom as a function of the refrigerant 16 in the dishwasher control unit 32, are set at a low level. By deliberately increasing the speed of the exhaust air fan 39 using a controller programmed in the machine control unit 32, the amount of room air / vapour mixture 43 pumped increases, and more heat is thus supplied to the evaporator 7.As a result, the evaporation pressure and evaporation temperature of the refrigerant 16 in the evaporator 7 rise, increasing both the power and efficiency of the heat pump 1. The speed of the exhaust air fan 39 is increased until the evaporation pressure measured by the low-pressure sensor 14 and the evaporation temperature of the refrigerant 16 determined from it in the dishwasher control unit 32 correspond to a defined target value or a maximum value that must not be exceeded.

[0081] Conversely, this control of the exhaust air fan 39 can also ensure, in dishwashers 2 which do not have a drying zone 53 and which suck in the room air / vapour mixture at both the first and second intake areas 34, that the significantly higher temperature and humidity in front of the evaporator 7 in this dishwasher configuration does not lead to high evaporation pressures or evaporation temperatures of the refrigerant 16 and that the compressor 8 is therefore operated outside its specified operating limits.If the evaporation pressure within the evaporator 7 measured by the low-pressure sensor 14 and the evaporation temperature of the refrigerant 16 determined from it increases due to the absence of a drying zone 53 and / or corresponding operating, installation, and / or ambient conditions that result in a higher temperature / humidity below the evaporator 7, the described control system reduces the speed of the exhaust air fan 39 until the evaporation pressure measured by the low-pressure sensor 14 and the evaporation temperature of the refrigerant 16 determined from it again correspond to a defined setpoint or a minimum value that must not be undercut. Another positive effect is that the temperature of the exhaust air 66 also decreases due to the aforementioned reduction in the speed and flow rate of the exhaust air fan 39.

[0082] Furthermore, the condensation pressure in the condenser 9 of the heat pump 1, which can be measured by the high-pressure sensor 13, is an indication of how far the rinsing liquid 24 required for the rinsing process in the rinsing tank 26 has already been heated, or whether further heating is still required and, approximately, to what extent. If the condensation pressure measured by the high-pressure sensor 13 and the condensation temperature derived from it depending on the refrigerant 16 exceeds a defined target value, preferably 75°C, then a further control programmed in the dishwasher control unit 32 slowly reduces the control and thus the speed of the exhaust air fan 39 until the target condensation temperature, preferably 75°C, is reached again.Since this reduction in control and the resulting reduction in the speed of the exhaust air fan 39 also result in the evaporation pressure of the refrigerant 16 measured by the low-pressure sensor 14 and the evaporation temperature of the refrigerant 16 determined therefrom as a function of the refrigerant 16 also falling and possibly falling below a defined minimum value, the control of the exhaust air fan 39 is then limited to the target value of the condensation temperature and the control and, consequently, the speed of the exhaust air fan are not reduced any further. The control of the exhaust air fan 39 to the evaporation temperature of the refrigerant 16 takes priority, and therefore the control and, consequently, the speed of the exhaust air fan 39 are increased again by the control until the defined minimum value of the evaporation temperature of the refrigerant 16 in the evaporator 7 is reached again.

[0083] By cleverly linking and superimposing the controls described above depending on their priority, the control and consequently the speed of the exhaust air fan 39 can be adjusted so that the cooling circuit 6 of the heat pump 1 is always operated in the range of optimal performance and efficiency, depending on the configuration of the dishwasher 2, as well as its operating, installation and ambient conditions.

[0084] Since, as already described, the amount of room air / vapour mixture 43 required in the air system 33 for optimal operation of the heat pump 1 and conveyed by the exhaust air fan 39 can vary greatly depending on whether a drying zone 53 is present or not, different start controls and resulting start speeds can be defined and implemented for the control of the exhaust air fan 39. If a drying zone 53 is present, the controls of the exhaust air fan 39 start at a higher defined level than if there is no drying zone 53, since with the drying zone 53, as already described, the temperature and humidity of the room air / vapour mixture 43 below the evaporator 7 are lower than if there is no drying zone 53. This measure helps the controllers to reach and regulate their setpoints more quickly.

[0085] As particularly in Fig. 2, the heat pump device 1 may comprise a high-pressure sensor 13 for detecting a condensing pressure of the refrigerant 16; wherein the heat pump device 1 comprises an expansion valve 11; and wherein, when the detected condensing pressure exceeds a maximum condensing pressure, the control unit 32 is configured to close the expansion valve 11 to such an extent and / or for such a length of time until the detected condensing pressure reaches the maximum condensing pressure or a second target condensing pressure or a minimum condensing pressure.

[0086] In other words: When the heating requirement of the rinsing liquid 24 contained in the rinsing tank 26 is lower and the temperature of the rinsing liquid 24 is therefore correspondingly high, close to a defined target temperature, the condensation pressure and the resulting condensation temperature of the refrigerant 16 in the condenser 9 also increase and may possibly exceed the specified operating limits of the compressor 8. To prevent this and a possible undesired premature shutdown of the heat pump 1, according to one aspect of the present invention, the electronic expansion valve 11 can be slowly closed until the condensation pressure and the resulting condensation temperature of the refrigerant 16 have fallen below a defined value again.A resulting increase in the superheat of the refrigerant 16 downstream of the evaporator 7 and a decreasing evaporation pressure of the refrigerant 16 in the evaporator 7 can be accepted within defined limits. This measure allows the heat pump 1, and thus the energy recovery from the room air / vapor mixture 43, to remain active for a certain period of time even at a higher temperature of the rinsing liquid 24 in the rinsing tank 26. A necessary shutdown of the heat pump 1 can thus be delayed. The room air / vapor mixture 43 extracted by the air system 33 during the rinsing process can thus continue to be cooled and dehumidified, which in turn positively benefits the climatic conditions in the installation room 45.

[0087] As particularly in Fig. 2, the heat pump device 1 may comprise a low-pressure sensor 14 for detecting an evaporation pressure of the refrigerant 16 and a high-pressure sensor 13 for detecting a condensation pressure of the refrigerant 16; wherein the control unit 32 is configured to determine a pressure difference between the detected condensation pressure and the detected evaporation pressure and, if the pressure difference does not exceed a predetermined minimum differential pressure within a predetermined time interval from a start time of the heat pump device 1, to output a signal.

[0088] In other words, the heat pump device 1 may comprise a compressor 8, wherein an incorrect direction of rotation of the compressor 8 can be detected by means of a calculated pressure difference between the high-pressure sensor 13 and the low-pressure sensor 14.

[0089] A correct electrical rotating field and therefore a correct direction of rotation of the compressor 8 is essential for the function of the heat pump 1, since otherwise no refrigerant 16 can be pumped by the compressor 8 and this can be irreparably damaged.

[0090] Since it cannot be completely ruled out that two phases of the three-phase power supply are swapped in the electrical installation of both the dishwasher 2 and the heat pump 1, or the electrical installation of the installation room 45, but an expensive electrical rotating field monitoring device is to be dispensed with, according to one aspect of the present invention, a possibly incorrect rotating field of the compressor 8 is determined indirectly by means of a pressure difference between the high-pressure sensor 13 and the low-pressure sensor 14 calculated via the dishwasher control unit 32.

[0091] After a defined time after the start of the compressor 8 of the heat pump 1, the pressure difference between the condensation pressure of the refrigerant 16 measured by the high-pressure sensor 13 and the evaporation pressure of the refrigerant 16 measured by the low-pressure sensor 14 must exceed a predefined minimum differential pressure. With a correct rotating field and the resulting correct direction of rotation, the compressor 8 exceeds the corresponding pressure difference within, i.e., before the defined time is reached. If, however, the defined pressure difference is not exceeded within the defined time, this can be concluded that the rotating field at the compressor 8 is incorrect. In this case, the dishwasher control unit 32 deactivates the compressor 8 again, and a corresponding error message is displayed to the operator, who can then request that this error be rectified.

[0092] Fig. 6A shows the fan housing and fan cover when the fan cover is in the cover position; Fig. Figure 6B shows the fan housing and fan cover when the fan cover is in the removal position; Fig. Figure 6C shows an enlarged section of Fig. 6B; and Fig. Figure 6D shows another enlarged section of Fig. 6B.

[0093] As particularly in Fig.6A to 6D, the dishwasher 2 may comprise a fan housing 42 and a fan cover 67; wherein the fan housing 42 is arranged relative to the heat pump device 1 in a height direction and is configured to receive the exhaust air fan 39; wherein the fan cover is arranged to be linearly movable relative to the fan housing 42 along a depth direction between a covering position for covering the exhaust air fan 39 in the height direction and a removal position for removing the fan cover 67 from the exhaust air fan 39, wherein the depth direction is perpendicular to the height direction.The fan housing 42 may include a guide member 70 and a holding member 68; wherein the guide member 70 extends in the depth direction and is configured to guide the fan cover 67 between the covering position and the removal position; and wherein the holding member 68 is configured to be elastically deformable relative to the guide member 70 such that, when the fan cover 67 is in the covering position, the holding member 68 presses the fan cover 67 against the guide member 70, thereby fixing the fan cover 67 in the height direction.

[0094] In other words, the dishwasher 2 can comprise a fan housing 42 with a cover 67 that can be pulled out to the front for easier cleaning or maintenance even when the installation space 45 is low.

[0095] Since the commercial conveyor dishwasher 2 with heat pump housing 15 and fan housing 42 located thereon can reach almost up to the ceiling of the installation room 45 depending on the height of the installation room 45, the fan housing 42 is designed according to one aspect of the present invention such that maintenance or cleaning work can still be carried out easily and quickly.

[0096] Due to the overall height of the dishwasher 2 with heat pump 1 and fan housing 42, the cover of the fan housing 67 cannot be removed upwards, depending on the height of the installation space 45. To still ensure accessibility to the exhaust air fan 39, the cover 67 can be easily pulled out horizontally after loosening just two screws and thus removed. When sliding in and out, the cover 67 is held, guided, and pressed against the upper stop tabs 70 by two front-facing metal tabs 68 and a rear-facing fixing rail 69.

[0097] The front sheet metal tabs 68 are designed in such a way that the stiffening tabs 71 of the cover 67 can be inserted into a defined gap 72 which is formed between the front sheet metal tabs 68 and the fan housing 42.

[0098] The exhaust air fan 39, attached to a separate fan bracket 73 mounted on top of the heat pump housing 15, is now easily accessible for maintenance and cleaning purposes after removing the cover 67. After completing the work, the cover 67 can simply be pushed back into the fan housing 42 and secured thereto. List of reference symbols 1 heat pump device, heat pump 2 Dishwasher, conveyor dishwasher 3 Machine air, machine exhaust air, vapors 4 Ambient air, room air 5 Dishes, dishes 6 refrigeration circuit, refrigeration circuit 7 evaporators 8 compressors 9 Condenser 10 subcoolers 11 Expansion valve 12 refrigeration circuit pipes 13 High pressure sensor 14 Low pressure sensor 15 heat pump housing 16 Refrigerants 17 Intermediate circuit, secondary intermediate circuit 18 Intermediate fluid, secondary fluid 19 intermediate circuit hollow body 20 Dishwasher interior 21 storage tanks 22 intermediate circuit pump 23 coaxial heat exchangers 24 Flushing liquid 25 lye cycle, lye cycle 26 Rinse tank 27 Lye circuit pump, tank circulation pump 28 lye circle hollow bodies 29 Intermediate circuit filling valve 30 overflow hose 31 Rinse zone, rinse zone 32 Control unit, dishwasher control unit 33 Air system 34 First intake area 35 Dish inlet side, machine inlet area 37 Dish outlet side 38 Additional room air intake 39 Exhaust air fan 40 system of air pipes 42 fan housing 43 Air mixture, room air / vapour mixture 44 openings in the fan housing 45 Surrounding area, installation room 46 Filter unit, grease filter 47 Temperature sensor, intermediate circuit temperature sensor 48 boilers 49 Rinse pump 50 water network separators, Airgap 51 Rinse zone, pre-rinse zone 52 Rinse zone, main rinse zone 53 Dry Zone 66 exhaust air 67 Cover 68 Holding element, front sheet metal tab 69 Rear fixation rail 70 Guide element, stop tab 71 stiffening tab 72 gap 73 Fan console 91 Inlet water 92 Wastewater 93 Rinse liquid 94 Rinse system 95 Transport device 96 blowers QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 111 670 B3

[0002]

Claims

[1] Dishwasher (2), comprising: a rinsing zone (51, 52, 31) for receiving items to be cleaned (5); a heat pump device (1) comprising a refrigeration circuit (6) in which a refrigerant (16) circulates; a suction device (34, 38, 39) configured to suck in machine air (3) from an interior region of the dishwasher (2) and ambient air from an ambient region of the dishwasher (2) and to supply an air mixture (43) of the machine air (3) and the ambient air to the heat pump device (1); and a control unit (32); wherein the heat pump device (1) comprises an evaporator (7) configured to transfer heat from the air mixture (43) to the refrigerant (16); i) wherein the heat pump device (1) comprises a high-pressure sensor (13) for detecting a condensation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected condensation pressure, and / or ii) wherein the heat pump device (1) comprises a low-pressure sensor (14) for detecting an evaporation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected evaporation pressure. [2] Dishwasher (2) according to claim 1, wherein the heat pump device (1) comprises a low-pressure sensor (14) for detecting an evaporation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected evaporation pressure; wherein, if the detected evaporation pressure falls below a minimum evaporation pressure, the control unit (32) is configured to increase the volume flow until the detected evaporation pressure reaches the minimum evaporation pressure or a first target evaporation pressure or a maximum evaporation pressure. [3] Dishwasher (2) according to one of the preceding claims, wherein the heat pump device (1) comprises a low-pressure sensor (14) for detecting an evaporation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected evaporation pressure; wherein, if the detected evaporation pressure exceeds a maximum evaporation pressure, the control unit (32) is configured to reduce the volume flow until the detected evaporation pressure reaches the maximum evaporation pressure or a second target evaporation pressure or a minimum evaporation pressure. [4] Dishwasher (2) according to one of the preceding claims, wherein the heat pump device (1) comprises a low-pressure sensor (14) for detecting an evaporation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected evaporation pressure; wherein the control unit (32) is configured to determine an evaporation temperature of the refrigerant (16) based on the detected evaporation pressure of the refrigerant (16) and to control the volume flow based on the determined evaporation temperature. [5] Dishwasher (2) according to one of the preceding claims, wherein the heat pump device (1) comprises a high-pressure sensor (13) for detecting a condensation pressure of the refrigerant (16); wherein the control unit (32) is configured to control a volume flow of the air mixture (43) supplied to the heat pump device (1) based on the detected condensation pressure; i) wherein, if the detected condensing pressure falls below a minimum condensing pressure, the control unit (32) is configured to increase the volume flow until the detected condensing pressure reaches the minimum condensing pressure or a first target condensing pressure or a maximum condensing pressure, and / or ii) wherein, if the detected condensing pressure exceeds a maximum condensing pressure, the control unit (32) is configured to reduce the volume flow until the detected condensing pressure reaches the maximum condensing pressure or a second target condensing pressure or a minimum condensing pressure. [6] Dishwasher according to claim 5, wherein the control unit (32) is configured to determine a condensing temperature of the refrigerant (16) based on the detected condensing pressure of the refrigerant (16) and to control the volume flow based on the determined condensing temperature. [7] Dishwasher (2) according to one of the preceding claims, which is configured such that a drying zone (53) can be mounted on or in the dishwasher (2); wherein the control unit (32) is configured such that a starting value for the volume flow is higher when the drying zone (53) is mounted on or in the dishwasher (2) than when the drying zone (53) is not mounted on or in the dishwasher (2). [8] Dishwasher (2) according to one of the preceding claims, wherein the suction device (34, 38, 39) comprises an exhaust air fan (39) with a controllable speed; wherein the control unit (32) is configured to control the volume flow by controlling the speed of the exhaust air fan (39). [9] Dishwasher (2) according to claim 8, wherein the dishwasher (2) comprises a fan housing (42) and a fan cover (67); wherein the fan housing (42) is arranged in a height direction relative to the heat pump device (1) and is designed to accommodate the exhaust air fan (39); wherein the fan cover is arranged to be linearly movable relative to the fan housing (42) along a depth direction between a covering position for covering the exhaust air fan (39) in the height direction and a removal position for removing the fan cover (67) from the exhaust air fan (39), the depth direction being perpendicular to the height direction. [10] Dishwasher (2) according to claim 9, wherein the fan housing (42) comprises a guide element (70) and a holding element (68); wherein the guide element (70) extends in the depth direction and is designed to guide the fan cover (67) between the covering position and the removal position; and wherein the holding element (68) is designed to be elastically deformable relative to the guide element (70), so that when the fan cover (67) is in the covering position, the holding element (68) presses the fan cover (67) against the guide element (70) and thereby fixes the fan cover (67) in the height direction. [11] Dishwasher (2) according to one of the preceding claims, wherein the heat pump device (1) comprises a high-pressure sensor (13) for detecting a condensation pressure of the refrigerant (16); wherein the heat pump device (1) comprises an expansion valve (11); and wherein, if the detected condensation pressure exceeds a maximum condensation pressure, the control unit (32) is configured to close the expansion valve (11) to such an extent and / or for such a length of time until the detected condensation pressure reaches the maximum condensation pressure or a second target condensation pressure or a minimum condensation pressure. [12] Dishwasher (2) according to one of the preceding claims, wherein the heat pump device (1) comprises a low-pressure sensor (14) for detecting an evaporation pressure of the refrigerant (16) and a high-pressure sensor (13) for detecting a condensation pressure of the refrigerant (16); wherein the control unit (32) is configured to determine a pressure difference between the detected condensation pressure and the detected evaporation pressure and, if the pressure difference does not exceed a predetermined minimum differential pressure within a predetermined time interval from a start time of the heat pump device (1), to output a signal. [13] Dishwasher (2), preferably according to one of the preceding claims, wherein the dishwasher (2) is a conveyor dishwasher (2) having a dish inlet side (35) and a dish outlet side (37), wherein the conveyor dishwasher (2) comprises: a dishwasher housing having a dish inlet opening on the dish inlet side (35) for letting dishes (5) to be cleaned into the dishwasher (2) and a dish outlet opening on the dish outlet side (37) for discharging the cleaned dishes (5) from the dishwasher (2); at least one rinsing zone (51, 52, 31) for cleaning the items to be washed (5); at least one drying zone (53) for drying the cleaned items to be washed (5), wherein the at least one drying zone (53) is formed separately from the at least one rinsing zone (51, 52, 53); a heat pump device (1) comprising a refrigeration circuit (6) in which a refrigerant (16) circulates; and a suction device (34, 38, 39) configured to suck in machine air (3) from an interior region of the dishwasher (2) and first ambient air from a first ambient region on the dish inlet side (35) of the dishwasher (2) and to supply an air mixture of the machine air and the first ambient air to the heat pump device (1), and to suck in second ambient air from a second ambient region of the heat pump device (1) and to supply it to the heat pump device (1); wherein the heat pump device (1) comprises an evaporator (7) configured to transfer heat from the air mixture (43) to the refrigerant and configured to transfer heat from the second ambient air to the refrigerant. [14] Dishwasher (2) according to claim 13, wherein the heat pump housing (15) has one or more heat pump housing openings for admitting the second ambient air into the dishwasher (2). [15] Conveyor dishwasher (2) according to claim 14, which comprises a transport device (95) for transporting the items to be cleaned along a transport direction from the dish inlet side (35) to the dish outlet side (37); wherein the evaporator (7) extends over an extension area in the transport direction; wherein the one or more heat pump housing openings are designed and positioned such that they lie at least partially or completely within the extension area of ​​the evaporator (7) in the transport direction or at least partially overlap with the extension area of ​​the evaporator (7) in the transport direction. [16] Dishwasher according to one of claims 13 to 15, wherein the heat pump device (1) comprises a filter unit (46) for filtering the second ambient air, wherein the suction device (34, 38, 39) is configured to supply the filtered second ambient air to the evaporator (7), wherein preferably the filter unit (46) is arranged within the heat pump housing (15).

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