DE102022000060A1 - Device for cleaning items to be cleaned - Google Patents

Abstract

2.1 Devices for cleaning items to be cleaned are particularly widespread in the form of washing machines and dishwashers. According to the state of the art, the process water used in it is usually heated by an electric heating element, which converts electrical energy into the same amount of heat energy. The object of the invention is to provide a device which heats the process water more energy-efficiently and has a reduced energy requirement compared to the prior art. 2.2 According to the invention, a device (10) for cleaning items to be cleaned is provided, comprising a process chamber (14) for receiving items to be cleaned and an air-water heat pump (12) which has at least one refrigerant compressor (16) and at least one coolant condenser (18) for transferring the heat of the refrigerant to the process water provided for cleaning the items to be cleaned. The refrigerant evaporator (20) of the air-to-water heat pump is provided with a fan (22) which is designed to convey ambient air through the refrigerant evaporator (20) and thereby heat the refrigerant in the refrigerant evaporator (20).2.3 A device according to the invention can be used in particular for the energy-efficient cleaning of textiles or dishes.

Description

The present invention relates to a device, in particular a washing machine or dishwasher, for cleaning items to be cleaned, comprising a process chamber which is set up to accommodate items to be cleaned.

Washing machines and dishwashers are among the largest consumers of electricity in private households. Since such devices are very widespread in industrialized countries, the cumulative power consumption of all these household devices together accounts for a considerable proportion of the country's total power consumption. Energy-saving household appliances thus make an important contribution to avoiding greenhouse gas emissions and protecting the climate.

Power plants that use renewable energy sources are increasingly being installed worldwide. In this context, particular mention should be made of wind turbines, photovoltaic systems and solar thermal power plants. These have the property that their power generation fluctuates over time. Photovoltaic systems cannot contribute to power generation at night and depend on the degree of cloudiness during the day. The generating capacity of wind turbines also depends heavily on the meteorological conditions. In an electricity grid dominated by renewable energy sources, there are therefore phases of overproduction of electricity, but possibly also phases of electricity shortage. The regulated switching on and off of consumers (load management, "demand side management") is therefore becoming increasingly important. In particular, the so-called "power-to-heat" approach, which is based on converting redundant electrical power into usable heat, is increasingly being used, for example in district heating networks or electrically operated heating systems. Small-scale, decentralized electrical devices that can be remotely controlled for load management purposes are often referred to as "smart grid devices".

The vast majority of the power consumption of a washing machine, like a dishwasher, is due to heating the washing water. With a few exceptions, today's devices still use an electrical heating element to heat the process water, which converts electrical energy into the same amount of thermal energy. While pure electric heaters in building technology have long been pushed out for reasons of efficiency, they still represent the state of the art for washing machines and dishwashers. Furthermore, almost all of today's washing machines and dishwashers have the property of discharging the warm process water via a waste water pipe after the end of a warm cleaning process to be pumped into the sewage system without the thermal energy contained therein being put to any further use.

Water can be heated much more efficiently using electrical energy if a heat pump is used, which extracts heat from a cold heat reservoir in its vicinity and feeds it to the water to be heated as useful heat. The quotient of the thermal energy delivered to the water and the electrical energy used for this is usually referred to as the effective number of a heat pump, or in English as the "coefficient of performance", COP for short. This effective number is ultimately limited by the laws of thermodynamics, which sets the efficiency of Carnot's cycle process as the upper limit. This degree of efficiency is lower, the higher the temperature difference between the two heat reservoirs, from the colder part of which the heat pump transfers heat to the warmer part. The effective numbers of real implementations of heat pumps usually remain far below the Carnot limit. With air-water heat pumps, which are increasingly used in building technology and use the outside air as a cold heat reservoir, effective numbers of the order of 3 to 5 are common.

From the DE 10 2004 023 126 A1 and the EP 2 096 203 A1 a washing machine is known which uses a water-water heat pump in order to work more energy-efficiently. The heat pump used therein is characterized in that it transfers heat between two heat reservoirs, both of which contain a liquid heat transfer medium. In the refrigerant evaporator, the refrigerant absorbs heat, which is extracted from a water reservoir, and in the refrigerant condenser, it gives off heat to the process water. The disadvantage of this concept is that the heat capacity of the heat-emitting water reservoir, which is located inside the machine, is limited and this is correspondingly greatly cooled. As a result, the heat pump has to work against an ever-increasing temperature difference, which reduces its effective number.

Both from the DE 10 2004 023 126 A1 and the EP 2 096 203 A1 as well as the DE 36 09 277 A1 a device for recovering heat from waste water in a washing machine is known. This is based on the fact that the heat from the waste water is at least partially transferred to fresh water, which is used in a subsequent cleaning process. It can be provided, for example, that warm waste water is not initially pumped out of the machine, but rather in stored in a dedicated container inside the machine. As soon as warm water is needed again inside the machine for a cleaning process, the heat content of the stored waste water is used to heat fresh water. Either a heat exchanger or a water-to-water heat pump is used for this.

From the DE 10 2014 118 799 A1 a washer-dryer is known which uses a common heat pump unit for a washing and a drying process. During the washing process, the heat pump unit acts as a water-water heat pump in analogy to that from the EP 2 096 203 A1 known washing machine. During the drying process, the heat pump unit acts as an air-to-air heat pump, which alternately cools and heats the process air used to dry the laundry, in line with the design of the heat pump tumble dryers that are commercially available today. Switching valves in the refrigerant circuit are used to select the refrigerant evaporator and refrigerant condenser required for the respective operating mode (washing or drying).

From the DE 20 2010 011 953 U1 a compressor for heat pumps is known, which is enclosed by a thermal absorber for the use of its waste heat, through which flows a fluid absorbing the heat.

From the DE 19 937 629 A1 a drive motor for a washing machine drum is known, which can be cooled by a cooling device through which a cooling medium flows.

From the DE 20 2021 002 165 U1 and the DE 20 2021 002 540 U1 a washing machine or a dishwasher is known, the electric heating rod serving to heat the process water is provided with an electronic power throttling. The electrical power consumption of the heating element is regulated in such a way that it can be completely covered by a regenerative power generation system, which is in the same electrical house network as the washing machine or dishwasher.

Against this background, the object of the invention is to provide a device for cleaning items to be cleaned which has a reduced energy consumption compared to the cleaning devices known from the prior art.

This object is achieved according to the invention by a device, in particular a washing machine or a dishwasher, for cleaning items to be cleaned, comprising a process chamber which is designed to accommodate items to be cleaned, and an air-to-water heat pump, the air-to-water heat pump having at least one Has a refrigerant compressor for heating a refrigerant and at least one refrigerant condenser for transferring the heat of the refrigerant to the process water provided for cleaning the items to be cleaned.

The device according to the invention can in particular be embodied as a household appliance, which is generally known as “white goods”. Such a household appliance usually includes a housing in which the process chamber can be accommodated, at least one power connection and at least one inflow and at least one outflow, with the latter usually being set up to introduce process water into the device or drain process water out of the device. The process chamber can be designed depending on the nature and volume of the items to be cleaned. A cylindrical washing tub of a washing machine or a cuboid rinsing chamber of a dishwasher can be regarded as an example of a corresponding process chamber. Furthermore, the process chamber is set up to be at least partially filled with process water after receiving the items to be cleaned, for example textiles or dishes. Optionally, a cleaning agent can be added to the process water before filling the process chamber or in the process chamber.

The cleaning of items to be cleaned is usually carried out at a temperature which is above room temperature and represents a desired process temperature. It is therefore necessary to heat the process water to a desired process temperature. According to the invention, an air-water heat pump is provided for heating the process water, which conveys a refrigerant which is in a gaseous state under normal conditions. In addition to carbon dioxide (R744), hydrocarbons or halogenated hydrocarbons in particular can be considered as refrigerants, for example 1,1,1,2-tetrafluoroethane (R134a), difluoromethane (R32), propane (R290), isobutane (R600a), or mixtures of fluorinated ones Hydrocarbons, for example R407c, R410a or R404a.

To heat the process water, the air-water heat pump of the device according to the invention comprises an electrically driven refrigerant compressor, which can be used, for example, as a piston compressor or a scroll compressor. Compressor is formed, and a refrigerant condenser, in which the compressed refrigerant can give off heat to the process water to be heated and thereby undergoes a phase transition from the gaseous to the liquid state of aggregation.

In order to transfer the heat generated by the air-to-water heat pump to the process water in the process chamber as efficiently as possible, it can be particularly advantageous for the refrigerant condenser to be in thermal contact with the process chamber. In order to heat the process water in the process chamber of the device according to the invention, the refrigerant condenser can be arranged in a lower area of the process chamber, so that it is at least partially covered by process water during a cleaning process. The refrigerant condenser, which can be designed, for example, as a meandering tubular structure, can in particular be made of a material that has a sufficiently high chemical resistance to the process water and the cleaning agent dissolved therein. Optionally, the refrigerant condenser can be made of a pliable or flexible material in order to be able to deform in the course of vibrations or other movements that can occur during a cleaning process within the process chamber.

Alternatively, the refrigerant condenser can be designed as a flow heater for water in the form of a heat exchanger, through which the process water is conveyed using a pump. For this purpose, the heat exchanger comprises in particular two circuit systems, the refrigerant circulating in a first circuit system and the process water to be heated in a second circuit system. The second circulatory system is set up to convey process water from the process chamber to the heat exchanger and from the heat exchanger into the process chamber. The second circulation system allows process water, which was previously heated via the heat exchanger, to be efficiently pumped through the process chamber, thereby distributing heat evenly in the process chamber. The refrigerant condenser of the air-to-water heat pump, which is designed as a heat exchanger, can in particular be arranged outside of the process chamber. An external heat exchanger has the advantage that it is easier to reach for maintenance or repair work and does not have to be removed from the process chamber first.
In such a case, the heat exchanger can be structurally designed in such a way that as little process water as possible remains in the heat exchanger after the heating of the process water has ended. This can be achieved by the heat exchanger having the smallest possible internal volume on the water side or by emptying it after the process water has been heated. The latter can be passive, e.g. by arranging the heat exchanger above the process chamber and allowing the process water to drain automatically under the influence of gravity after a feed pump that pumps the process water through the refrigerant condenser has been switched off, or actively by a feed pump and switching valves taking care of this that the process water is conveyed out of the heat exchanger and further process water is prevented from flowing in. In particular, an air pump can also be used, which blows out the remaining process water from the heat exchanger. In order to achieve air bubble-free filling of the water side of the heat exchanger with process water when heating process water, a vacuum pump can be provided, which evacuates the heat exchanger or lowers the air pressure in it at least below the saturation vapor pressure of water, so that the water vapor produced largely displaces the residual air. Advantageous forms of realization of a refrigerant condenser designed as a heat exchanger are, for example, a stainless steel plate heat exchanger, which was manufactured from stainless steel sheets by hard soldering with a solder containing copper, or a coaxial tube construction in which an inner tube through which refrigerant flows is coaxially enclosed by a second tube on the outside , whereby the space between the two pipes is traversed by process water. Insofar as the heat exchanger, due to its design, is prone to substances in the process water precipitating in it and impairing its function, a filter which retains such substances, for example in the form of a fine-meshed sieve, can be connected upstream of this.

Preferably, the air-to-water heat pump may have a pressurized refrigerant circuit through which the refrigerant is pumped. If the air-to-water heat pump is designed as a circulatory system, it can also include at least one refrigerant evaporator for evaporating condensed refrigerant and at least one fan for heating evaporated refrigerant with ambient air. In the device according to the invention, the refrigerant evaporator, in which the refrigerant evaporates and thereby absorbs heat, of the air-to-water heat pump can be designed as a heat exchanger through which a fan can convey ambient air. It can be provided within the refrigerant evaporator, a refrigerant line, which at is designed, for example, as a metal tube and is preferably arranged in a meandering shape, it being possible for the refrigerant line to be connected in a thermally conductive manner to a plurality of parallel metal fins.

The air routing of the blower can preferably be designed in such a way that the device or the housing of the device is equipped with at least one inlet opening for ambient air, through which ambient air is sucked in, preferably in the area of the front of the device, and with at least one outlet opening, through which the air Flow of the refrigerant evaporator can be blown out again preferably in the bottom area or on the rear or side wall of the device or the housing of the device. The air inlet and air outlet openings can be designed in such a way that there is complete protection against accidental contact for moving components of the fan. Water vapor from the ambient air condensing out in the refrigerant evaporator can be collected in the form of liquid condensed water and either disposed of via a waste water line or a drain of the device or made usable for cleaning processes.

In addition, the refrigerant circuit can have an expansion valve between the refrigerant condenser and the refrigerant evaporator, which ensures that an adequate pressure gradient is set between these two components of the refrigerant circuit. In the simplest case, the expansion valve can be designed as a capillary, but controllable expansion valves, which can be actuated by a mechanical thermostat or an electrical actuator, offer more degrees of freedom in controlling the air-water heat pump. Furthermore, the refrigerant circuit may include a liquid refrigerant receiver, which is downstream of the refrigerant condenser, and a liquid refrigerant separator, which is upstream of the refrigerant compressor and prevents incompressible liquid phase from getting into a suction line of the refrigerant compressor.

For the supply of fresh water to or into the device according to the invention, the device can be connected to at least one fresh water line, wherein the fresh water can be used as process water for cleaning items to be cleaned and in particular can be supplied to the process chamber. Furthermore, the device according to the invention for storing the fresh water can have at least one fresh water tank. The fresh water tank is advantageously set up to store fresh water and only release it to the process chamber when a cleaning process is imminent or when fresh water is to be heated via the air-to-water heat pump, for example for the forthcoming use as process water. The fresh water tank can in particular have thermal insulation in order to store fresh water therein in a heated state over a longer period of time with little loss.

Another technical feature of the present invention relates to the use or recovery of waste heat. Conventionally, the process water is drained off after the end of a cleaning process through a drain in order to be able to subject the cleaned items to be cleaned to subsequent process steps or to be able to remove them from the process chamber. However, any thermal energy stored in the process water is lost in this process. In an advantageous embodiment, the device according to the invention therefore has a heat exchanger which is set up to transfer heat from the process water heated by the air-to-water heat pump to ambient air or to fresh water. The heat exchanger can in particular be connected to the device in such a way that heated process water can flow through it following a warm cleaning process, with the corresponding process water also being referred to below as waste water.

In order to transfer the heat from the waste water to the ambient air surrounding the device, the heat exchanger can be designed as a water-air heat exchanger which has a plurality of fins and is equipped with a fan, the fan being set up to transfer heat from waste water to the ambient air is to convey ambient air through the heat exchanger. It is also conceivable that the water-air heat exchanger can be arranged in the form of a flat water pocket, for example on the side walls, on the back or on the front of the device, so that the corresponding outside of the device heats up and heat is released into the ambient air becomes. For this purpose, the outside of the device can advantageously be provided with a coating, for example a radiator paint, which promotes the emission of thermal radiation. Provision can also be made for the warm waste water to remain in the water pocket for a certain period of time until its temperature has dropped to room temperature. If a heat exchanger is used, which is designed as a water pocket, the device can advantageously be equipped with two sewage pumps or with a sewage pump with downstream switching valves, so that waste water water can be pumped from the process chamber either into the heat exchanger or directly into a drain. To empty the water bag after its contents have largely cooled down, an additional pump can be provided, which conveys the contents of the water bag to the outlet of the device.

Alternatively, the water bag can be designed with an overflow, which is connected to the outflow of the device, so that the cooled waste water can remain in the device until, in the course of a subsequent cleaning process, warm waste water is pumped into the water bag again and the already cooled waste water is pumped through suppresses the overflow.

In a further alternative embodiment, the heat exchanger can be provided as a tank with two separate chambers, the first of which is intended for waste water and the second of which is intended for fresh water, with a partition wall arranged between the first and second chamber being made of a material with good Thermal conductivity can be made and the chamber for waste water can be designed so that it is in good thermal contact with the ambient air. In particular, this allows a partial use of the heat from the waste water from a first warm cleaning process for a second cleaning process that follows the first, in that the second chamber is filled with fresh water. This can lead to a heat transfer from warm waste water to the fresh water until the temperatures of the waste water and the fresh water have equalized after a certain period of time. The fresh water from the second chamber that is heated in this way can then be used for the second cleaning process, for which it can then optionally be reheated by the air-water heat pump.

To further increase the energy efficiency of the device according to the invention, warm waste water can also be pumped through a water-water heat exchanger that works according to the countercurrent principle, in which the heat of the waste water can be transferred to fresh tap water. The water-water heat exchanger can in particular be designed and arranged in such a way that the waste water enters a first chamber at its top and exits cooled at its bottom. The fresh water can enter a second chamber at the bottom of the water-water heat exchanger and exit at the top in the heated state. In this way it can be achieved that a continuous temperature gradient is set in the vertical direction in the water-water heat exchanger and a heat stratification that is stable against convection is formed under the influence of gravity. The water-water heat exchanger can be provided with a large contact area between the two chambers and can be flowed through with low flow rates, so that an efficient heat transfer between fresh water and waste water can take place.

The device according to the invention can additionally be equipped with a thermally insulated fresh water tank into which the heated fresh water can flow after passing through the water-water heat exchanger. If a pumping-out process is initiated after a warm cleaning step, two liquid flows with a mass flow that is as identical as possible can be set in motion at the same time. On the one hand, a waste water pump can convey the warm waste water from the process chamber through the water-water heat exchanger into a waste water line of the device. On the other hand, an inflow of fresh water into the device can be initiated. In this case, the fresh water flows through the water-water heat exchanger and then reaches the insulated fresh water tank. If the process chamber is completely emptied by the pumping process, it can be advantageous to remove the residual water from the two chambers of the water-water heat exchanger, for example by pumping or blowing out with air. Additional pumps and valves can be provided for this purpose.

If a further warm cleaning process is to follow a waste water heat recovery process, the fresh water required for this cannot primarily be obtained from a fresh water supply line of the device, but from the insulated fresh water tank. A feed pump is provided for this purpose, which feeds water from the fresh water tank to the process chamber of the device, it being possible for a flow of water to be passed through a cleaning agent dispensing chamber. If the temperature of the fresh water in the fresh water tank exceeds the setpoint temperature or the process temperature for a subsequent warm cleaning process, cold fresh water from the inlet line can be added in the required ratio. However, if the fresh water temperature in the insulated fresh water tank is too low for the subsequent cleaning process, the process water can be additionally heated using the air-water heat pump, for example.

If the device according to the invention will not be used in the foreseeable future, but there is heated fresh water in the insulated fresh water tank, if desired, the heated fresh water can be pumped into the process chamber, which has less thermal insulation than the fresh water tank, so that the heat from the fresh water can be released to the ambient air via the process chamber.

The waste water heat recovery described allows a considerable part of the heating energy of the process water to be saved, especially in the case of warm cleaning processes that follow one another in quick succession, since only the first warm cleaning process requires complete process water heating by the air-water heat pump, while the waste water heat of the each previous warm cleaning process can be used.

Insofar as the cleaning process starts with the highest target temperature and the subsequent cleaning processes, which are also warm, are sorted according to monotonically falling target temperature, the situation can arise in particular that individual cleaning processes can do without any further use of heating energy.

Due to the almost adiabatic compression of the refrigerant in the refrigerant compressor, the heating of the current-carrying motor windings of the refrigerant compressor motor and internal friction losses within the refrigerant compressor, considerable heat can be generated in the refrigerant compressor. During the operation of the refrigerant compressor, a state of equilibrium is established in which the heat output occurring in the refrigerant compressor, minus any heat losses to the environment, corresponds to the net heat flow dissipated by the refrigerant. This state of equilibrium occurs at a relatively high temperature, so that the high-pressure side of the refrigerant compressor is often the warmest point in the entire refrigerant circuit. If the air-to-water heat pump is switched off, the refrigerant compressor usually remains in a heated state without the thermal energy contained in it being put to any further use. In an optional embodiment, the device according to the invention can therefore also be set up to transfer heat that occurs as a result of the operation of the refrigerant compressor to process water or to fresh water. In this regard, the refrigerant compressor can be designed with cooling water ducts or a water pocket, through which process water or fresh water can be conveyed after the air-water heat pump has been switched off, in order to be able to use the residual heat of the refrigerant compressor to heat the corresponding water. It is also conceivable to carry out the flow through the refrigerant compressor while it is in operation.

Furthermore, the principle of heat generation just described can optionally also be applied to other heat-generating or heat-radiating components of the device. At this point, an electric motor is particularly worth mentioning, which drives, for example, the washing drum of a washing machine or a circulating pump of a dishwasher. The electrical resistance of the motor windings can lead to a dissipation of electrical power within the electric motor. The heat released as a result can be utilized in the same way as the heat generated by the operation of the refrigerant compressor.

The device according to the invention can optionally include a switching device which is set up to allow the air-water heat pump to selectively heat the process water in the process chamber or heat the fresh water in the fresh water tank. If there are no items to be cleaned but the device can still generate heat via the air-water heat pump for a given reason, the device is advantageously able to heat fresh water in the fresh water tank via the switching device. After the fresh water has been sufficiently heated, the switching device can, if desired, enable process water to be heated in the process chamber via the air-water heat pump.

In an advantageous embodiment, the device according to the invention has control electronics for controlling the switching device and temperature sensors for monitoring the water heating. For example, the control electronics can enable a user of the device to select whether the air/water heat pump should heat the process water in the process chamber or whether fresh water in the fresh water tank should be heated. In addition, the control electronics of the device can be equipped with a function to activate the air-water heat pump and to heat the fresh water in the fresh water tank outside of a cleaning process and also in the absence of items to be cleaned in the process chamber in order to generate negative control power for the public power grid or to provide the home network in which the device is located. In particular, the control electronics can be provided with a receiving device which is set up in such a way that it can be used to receive data or control commands from an energy management system.

Furthermore, the control electronics of the device can decide based on a user input, based on a measurement of the ambient temperature of the device, based on communication with a heating or air conditioning system in the surrounding building or based on a query of meteorological data, whether cooling of a storage room of the device is desirable. In order to also be able to implement complex control and communication algorithms on the device according to the invention and to be able to adapt them to current conditions in a device located in a user's household later on easily and without physical access to the device, the device according to the invention can advantageously be equipped with control electronics be equipped, which not only uses programmable logic components, such as microcontrollers, CPLD (“Complex Programmable Logic Device”) or FPGA (“Field Programmable Gate Array”), but also includes an Internet-enabled control computer with a processor and operating system, for example a single-board computer. In this case, the device can be provided with connections for a computer screen and for input devices, such as a mouse and keyboard, or have such devices permanently installed, so that the user can also use numerous functions of an office computer on the device, and in particular can also establish an Internet connection .

In particular, the device can be provided with a remote maintenance function and offer the possibility of holding video conferences via a built-in or externally connected camera. In the event of malfunctions in the device, the user can thus be given the opportunity to contact customer service via a video connection and to have defects that have occurred in the device diagnosed via the remote maintenance function. A test run of the device with the aim of reproducing and diagnosing a previously occurring error pattern can be carried out in the presence of the user of the device without having to travel to customer service, whereby the user can be instructed via the video connection to take certain steps, for example inserting the device of items to be cleaned or turning on a water tap. In this way, necessary repair measures can be prepared on site in a more targeted manner.

Furthermore, the device can advantageously be equipped with temperature sensors at one or more points in the refrigerant circuit, in the process water or fresh water circuit and/or in the air flow of the refrigerant evaporator. In this way, the operating status of the air-to-water heat pump in particular can be monitored and critical operating statuses and faults in particular can be detected in good time, for example a failure of a fan motor of the refrigerant evaporator, a failure of the refrigerant compressor or overheating as a result of a failure of a feed pump for process or Fresh water or as a result of a water leak. Furthermore, it can be detected in this way if the refrigerant evaporator is icing up as a result of air humidity freezing out. In such a case, the control program of the device can provide for the refrigerant compressor of the air-water heat pump to be switched off temporarily in order to defrost the refrigerant evaporator.

The device according to the invention can advantageously be equipped with at least one fill level sensor and at least one temperature sensor, so that the control electronics of the device can detect the fill level and the water temperature in the fresh water tank and/or the process chamber. Furthermore, it can also be expedient to attach flow sensors and/or pressure sensors to the circulatory systems or their lines.

As already mentioned, for the purpose of waste water heat recovery, it can happen in particular that two liquid flows with a mass flow that is as identical as possible are set in motion at the same time. In this regard, the device can include a dual-circuit feed pump, which is set up to regulate a flow of process water exiting the process chamber and of fresh water. Such a dual-circuit feed pump can be designed in particular as a double-piston pump. In particular, the double-piston pump has identical piston surfaces and an identical stroke, with a first piston being able to pump waste water and a second piston being able to pump fresh water. In particular, both pistons can be mechanically coupled and provided with at least one return spring, wherein a pump cycle can be controlled via valves in such a way that the first piston is moved against a spring force by the pressure of the fresh water flowing in. The second piston, which is coupled to the first piston, sucks in waste water from the process chamber at the same time. After the fresh water supply is switched off by a control valve and the flow of water from the fresh water piston to a heat exchanger is released by another control valve, the spring force moves both pistons back to their original position. This allows equal amounts of fresh water and waste water to be pumped to a heat exchanger. In addition, this particularly allows pumping purely through the water pressure without the use of additional electrical energy.

Alternatively, the adjustment of the two mass flows in the pumping operation can be realized by a control circuit, which measures both mass flows and actively controls at least one of them, or by two mechanically coupled pumps for pumping waste water and fresh water, which can pump identical volume flows, for example in the form of two peristaltic pumps same geometry, which have a common drive shaft.

In order to use the heat generated or recovered by the air-to-water heat pump or waste water heat recovery in the long term, i. H. over a period of several days or weeks, the device according to the invention can, in an optional embodiment, have chemical heat storage devices for the long-term storage of heat generated by the device. The use of long-term chemical storage makes particular sense, since unavoidable heat losses occur even with complex insulation of the fresh water. In order to be able to achieve a longer storage period, chemical heat storage systems based on sodium acetate, for example, are ideal. Using waste water heat, fresh water heat or with the help of the air-water heat pump, a chemical heat accumulator can be heated in such a way that a chemical reaction that serves to charge it takes place. During the storage period, a cooling of the chemical heat accumulator to ambient temperature is accepted. When retrieving the storage content in the course of a desired warm cleaning process, the chemical reaction serving to release energy can be set in motion and the heat released as a result can be transferred to the process water.

Since the effective number of an air-to-water heat pump decreases as the temperature difference between the cold and warm heat reservoir increases, and the refrigerant pressure on the high-pressure side of the compressor must be higher the warmer the heat transfer medium in the refrigerant condenser is, air-to-water heat pumps can use water in many cases do not heat to boiling point. Air-to-water heat pumps can therefore be designed in such a way that they achieve good coefficients of efficiency in the lower temperature range, but the maximum water temperature is in the range of 65°C to 70°C, in particular through the choice of refrigerant. However, depending on the area of application, it can be advantageous or even necessary to achieve higher water temperatures, for example in white wash programs in washing machines. Therefore, the device according to the invention can have a heating element for heating the process water in addition to the air-water heat pump. The heating element can be switched on in particular when the air-to-water heat pump has reached its maximum process water heating temperature and has been switched off accordingly, but further heating of the process water is necessary. The immersion heater can also serve as a fallback solution to maintain the functionality of the device in the event that the air-to-water heat pump is not operational due to internal or external factors, such as a technical defect or too low room temperatures.

Optionally, the device according to the invention can also be set up to heat water from an external device or water storage tank connected to the device via the air-water heat pump. Since household appliances and in particular washing machines and dishwashers are often installed in rooms in which there are other electrical appliances that heat water using an electrical heating element, it can be advantageous to couple the device according to the invention with at least one such electrical appliance. For this purpose, the device can be equipped with a hot water outlet, via which a connected device can be supplied with hot water, with the hot water being able to represent both process water heated by the device and also heated fresh water. In particular, a washing machine according to the invention with an air-to-water heat pump can supply a neighboring washing machine without a heat pump with warm water and thus significantly reduce its energy requirements. The control electronics of the device according to the invention is expediently equipped with a communication interface to a neighboring washing machine in order to avoid a coincidence in time of the phases of water heating when both devices are operated at the same time, for example by inserting breaks in the program sequence.

Furthermore, the device according to the invention can be connected to a hot water tank of a building's own heating system, for example a service water tank or a buffer tank. In particular, the device can be able to heat the contents of the hot water tank via the air-to-water heat pump. For this purpose, either water can circulate between the hot water storage tank and the device, or an additional refrigerant condenser can be provided on or in the hot water storage tank, which is connected to the device via additional refrigerant lines. Furthermore, within the device, a switching valve in the refrigerant telkreis be provided, which selects between the internal and the external refrigerant condenser. A device designed in this way can, in particular, substitute a service water heat pump. By heating the contents of the external hot water tank by the device according to the invention, the primary energy requirement of the heating system into which the hot water tank is integrated can be reduced. In particular, the avoidance of heating cycles and cooling cycles can have a positive effect on the life of a boiler within the heating system, which would otherwise have to take over the task of heating the contents of the hot water tank. To control the heating of the contents of the hot water tank, the device according to the invention can be provided with a connection for an external temperature sensor. A communication interface to the control electronics of a heating system can also be provided.

In an optional embodiment of the device according to the invention, an air-to-air heat pump can be provided for drying the items to be cleaned. In particular in the case of household appliances which are equipped with an additional function for drying items to be cleaned, for example in the form of a washer-dryer, the refrigerant compressor of the device can also be used in a drying unit. The drying of items to be cleaned can be carried out in a particularly energy-efficient manner using an air-to-air heat pump, in which both the refrigerant evaporator and the refrigerant condenser use air as the medium as the heat carrier. To dehumidify the items to be cleaned, air can first be cooled in the refrigerant evaporator, so that the water vapor contained therein is partially condensed, and then heated in the refrigerant condenser. The air heated in this way can then flow around or through the items to be cleaned.

If a device according to the invention is equipped with a dryer function, only one refrigerant compressor can advantageously be provided, which is set up both for heating the process water during a cleaning process and for dehumidifying the items to be cleaned during a drying process. In order to be able to choose between heating the process water and drying or dehumidifying the items to be cleaned, switching valves can be arranged in the refrigerant circuit. Further simplifications can result if the refrigerant evaporator and possibly its blower are only available in a simple design and are used both for heating the process water and for drying the items to be cleaned. Adjustable air flaps can be used here to direct the air flow in the right direction depending on the functionality that is currently required.

Furthermore, the features described represent, among other things, various possible uses of an air-water heat pump for heating process water provided for cleaning items to be cleaned in a device according to the invention.

• 1 eine schematische Darstellung eines ersten Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung;
• 2 eine schematische Darstellung eines zweiten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung;
• 3 eine erweiterte schematische Darstellung des zweiten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung, welche eine Wärmerückführung von Abwasserwärme veranschaulicht;
• 4 eine alternative Ausführungsform der in 3 gezeigten schematischen Darstellung;
• 5 eine schematische Darstellung einer Wärmetauscher-Anordnung zur Rückgewinnung von Abwasserwärme, welche sowohl mit dem ersten Ausführungsbeispiel als auch mit dem zweiten Ausführungsbeispiel kompatibel ist;
• 6 eine schematische Darstellung einer alternativen Wärmetauscher-Anordnung, umfassend eine Doppelkolbenpumpe;
• 7 eine schematische Darstellung der erfindungsgemäßen Vorrichtung gemäß einem dritten Ausführungsbeispiel, welche sowohl eine Abwasserwärme-Rückgewinnung als auch eine Warmwasser-Speicherfunktion veranschaulicht; und
• 8 eine schematische Darstellung der erfindungsgemäßen Vorrichtung gemäß einem vierten Ausführungsbeispiel, welche eine Erwärmung von Wasser in einem externen Warmwasserspeicher veranschaulicht.

The present invention is described in more detail below by means of exemplary embodiments with reference to the accompanying drawings. It shows:

• 1 a schematic representation of a first embodiment of a device according to the invention;
• 2 a schematic representation of a second embodiment of the device according to the invention;
• 3 an expanded schematic representation of the second embodiment of the device according to the invention, which illustrates a heat recirculation of waste heat;
• 4 an alternative embodiment of the 3 shown schematic representation;
• 5 a schematic representation of a heat exchanger arrangement for the recovery of waste water heat, which is compatible with both the first embodiment and the second embodiment;
• 6 a schematic representation of an alternative heat exchanger arrangement, comprising a double piston pump;
• 7 a schematic representation of the device according to the invention according to a third embodiment, which illustrates both a wastewater heat recovery and a hot water storage function; and
• 8th a schematic representation of the device according to the invention according to a fourth embodiment, which illustrates a heating of water in an external hot water tank.

In the 1 until 8th a process chamber 14 of a device 10 according to the invention is shown cylindrical, corresponding to the usual embodiment of a washing tub in washing machines. A washing drum, which is used to hold textiles to be cleaned, is usually rotatably mounted in this washing tub. In dishwashers, the process chamber has mer 14, however, usually cuboid shape and contains rotatable spray arms. In the case of an embodiment as a dishwasher, the cuboid washing chamber takes the place of the cylindrical washing tub. However, the rinsing chamber or the washing tub are not limited to a cuboid or cylindrical shape and can also be designed in another shape. Line connections, which in the following figures end at the bottom and/or the top of the process chamber 14, can also be attached to the process chamber 14 in other ways and are shown in the figures purely as an example.

1 shows a schematic representation of a first exemplary embodiment of a device 10 according to the invention, which includes an air-water heat pump 12 . The air-to-water heat pump 12 has a refrigerant compressor 16 , a refrigerant condenser 18 and a refrigerant evaporator 20 with a fan 22 which conveys ambient air through the refrigerant evaporator 20 . The refrigerant condenser 18 is arranged here within a process chamber 14 and can also be provided in a lower region of the process chamber 14 of the device 10 according to the invention, so that it is in particular completely immersed in water during a cleaning process. This enables heat to be transferred from a refrigerant, which is transported through a circulatory system 24 of the air-to-water heat pump 12, to process water. The process water, which can be fed into the process chamber 14, is used to clean items to be cleaned.

The refrigerant can be, for example, carbon dioxide, a hydrocarbon, or a halogenated hydrocarbon and can be circulated through the circulation system 24 of the device 10 . The refrigerant compressor 16 is set up to compress the gaseous refrigerant, as a result of which the refrigerant heats up considerably. In the course of the compression of the refrigerant, it can be heated, for example, to approximately 60° C. to 70° C., with a pressure of approximately 20 bar to 40 bar being able to be generated. The heated refrigerant passes from the refrigerant compressor 16 into the refrigerant condenser 18 via the circulatory system 24 . There the heated refrigerant transfers heat to the colder process water, which is located inside the process chamber 14 . For example, the process water can be heated up to approx. 60°C due to the heat transfer. In return, the refrigerant, which is still compressed, cools down and condenses as soon as it reaches a pressure-dependent condensation temperature. This condensation temperature can vary depending on the refrigerant. To expand the liquid refrigerant, it can be expanded in particular by an expansion valve (in 1 not shown) are transported. The refrigerant evaporates and cools down, in particular to approx. < 5°C. In order to reach the initial temperature of the refrigerant, it is transported through the refrigerant evaporator 20, wherein the refrigerant can be heated to approximately 5° C. or more via ambient air, which is transported by the fan 22, and then fed back to the refrigerant compressor 16. In this way, the air-to-water heat pump is able to efficiently heat process water via a circulation system. The heating begins at the temperature at which the process water is initially present in the process chamber 14, for example the temperature of the cold tap water, and ends at the setpoint temperature of the process water. At this point it should be mentioned that lower process water temperatures, for example approx. 30°C, can also be generated for low-temperature cleaning processes.

In 2 a schematic representation of a second exemplary embodiment of the device 10 according to the invention is shown. Here, an air-to-water heat pump 12 includes a heat exchanger 26 which functions as a refrigerant condenser according to the flow heater principle and is arranged outside of the process chamber 14 . The heat exchanger 26 is connected to two hermetically separate circuits 24, 28, one of which is traversed by a refrigerant and the other by process water. A feed pump 30 is used here to feed the process water from the process chamber 14 to the heat exchanger 26 and back. The heat exchanger 26 can be designed as a stainless steel plate heat exchanger, for example.

Furthermore, the device can provide a process water drain (in 2 not shown), which is set up in particular to derive process water from the process chamber 14 after a cleaning process. In addition, a process water inflow (in 2 not shown) may be provided, which fills the process chamber 14 with fresh process water before a cleaning process. The fresh process water can then be fed into the circuit 28 for heating.

3 shows an expanded schematic representation of the second embodiment of the device 10 according to the invention, which illustrates a heat recirculation of waste heat. A switching valve 34 is connected downstream of a waste water feed pump 32, which can correspond to a drain pump according to the prior art in washing machines and dishwashers. In a first valve position, waste water can flow out of the device 10 via the discharge line 36 to be pumped. In a second valve position, on the other hand, water can get into a water pocket 38 which is integrated, for example, in a side wall of the device 10 . After a cleaning process with warm process water, the resulting waste water can be pumped into the water bag and remain there so that the heat contained in it can be transferred to the surrounding ambient air. If a cold cleaning process is subsequently carried out, the resulting waste water can be pumped out in the first valve position of the switching valve 34 , bypassing the water pocket 38 , directly into the drain line 36 of the device 10 . In this way, the waste water in the water pocket 38 that has not yet completely cooled down can remain in it longer without being prematurely displaced from it by the cold waste water of subsequent cleaning processes. A drain 40 located outside the device 10, which is U-shaped, for example, is used to drain waste water out of the device 10.

In 4 is an alternative embodiment of the 3 illustrated schematic representation shown, in which a partial utilization of the waste water heat for subsequent cleaning processes is implemented. Here the water pocket of the device 10 is designed in two parts and additionally comprises a chamber 42 for fresh water, the chambers 38, 42 being separated from one another by a partition wall which is as thermally conductive as possible. After the end of a warm cleaning process, as in 3 shown and the warm waste water pumped into the chamber 38 for waste water. There, however, this is not only in thermal contact with the surrounding ambient air, but also with the fresh water located in the fresh water chamber 42 . This leads to heat transfer from the warm waste water to the colder fresh water until the two temperatures have equalized. If warm water is required for a subsequent cleaning process, this can be obtained from the fresh water chamber 42 .

A simple solution for pumping warm fresh water from the fresh water chamber 42 into the process chamber 14 can be to supply fresh water via an inlet valve 44 to a lower area of the fresh water chamber 42, which has an overflow line 46 leading into the process chamber 14 in an upper area. If the device 10 is a washing machine for textiles, the overflow line 46 can also lead into a detergent dispensing chamber of the device 10 instead of directly into the process chamber 14 . If it is a dishwasher, provision can be made for fresh water to pass through an ion exchanger of the device 10 before it enters the fresh water chamber 42 . In addition to the inlet valve 44, another inlet valve (not shown) is advantageously formed, via which fresh water can be admitted directly into the process chamber 14 via an inlet line (not shown), bypassing the fresh water chamber 42. This allows cold cleaning operations to be performed while there is warm water in the fresh water chamber 42 .

5 Figure 12 is a schematic representation of a heat exchanger assembly for waste heat recovery compatible with both the first embodiment and the second embodiment. A waste water feed pump 32 pumps waste water from the process chamber 14 to an upper inlet of a counterflow heat exchanger 48, which is arranged in particular vertically the discharge line 36 following the heat exchanger 48 can be guided in such a way that it temporarily runs above an upper edge of the heat exchanger 48 . This ensures that the waste water side of the heat exchanger 48 can be completely filled with water. Fresh water reaches a controllable inlet valve 44 via an inlet line 50 of the device 10. If this inlet valve 44 is opened, fresh water enters the heat exchanger 48 from below, flows through it and reaches a thermally insulated fresh water tank 52 in a heated state. Heated fresh water can be removed from the fresh water tank 52 and, for example, in the process chamber 14 or in external devices or electrical devices (not shown) are fed.

In 6 Illustrated is a schematic representation of an alternative heat exchanger arrangement including a dual piston pump 54 . The double piston pump 54, which can be integrated into a device 10 with a countercurrent heat exchanger 48 for waste water heat recovery, ensures identical flow rates on the waste water and fresh water side and can also pump waste water solely through the fresh water pressure without the use of additional electrical energy. The double piston pump 54 has a pump housing 56, a working piston 58 for fresh water and a working piston 60 for waste water, which have identical effective areas and are rigidly coupled to one another, for example by both being connected to the same piston rod 62. A return spring 64 drives both pistons 58, 60 to their home position.

A water flow into a first working volume 68 of the working piston 58 can be brought about by opening a (preferably electrically) controllable supply valve 44 for fresh water. The working piston 58 is moved against the force of the return spring 64 by the fresh water pressure. The coupled working piston 60 for waste water moves synchronously therewith and thereby draws in waste water from the process chamber 14 via a first check valve 72 into a second working volume 70 . If the inlet valve 44 is then closed and a (preferably also electrically) controllable outlet valve 66 is opened, both working pistons 58, 60 are pressed back into the starting position by the force of the return spring 64. As a result, fresh water can be conveyed through the outlet valve 66 to the fresh water side of the counterflow heat exchanger 48 and at the same time an identical volume of waste water can flow through a second check valve 74 to the waste water side of the counterflow heat exchanger 48 . After both working pistons 58, 60 have returned to the starting position, the process can begin again. The piston rod 62 is expediently equipped with two end position switches 76, 78 or, alternatively, with a travel sensor (not shown) in order to be able to detect when the starting and end positions have been reached using an electronic control system.

7 shows a schematic representation of the device 10 according to the invention according to a third exemplary embodiment, which, by way of example, illustrates both a wastewater heat recovery function and a fresh water heating function. A device 10 which has such a dual function can function as a “smart grid” device. Here, an air-to-water heat pump 12, which includes a refrigerant compressor 16, a refrigerant evaporator 20 with a fan 22 and a heat exchanger 26, is provided with a first feed pump 30 on the water circuit side, and with two switching valves 34a and 34b, which are always switched simultaneously can. The switching valves 34a, 34b can be used to select whether the air/water heat pump 12 heats process water in the process chamber 14 or fresh water in the insulated fresh water tank 52. The latter opens up the possibility of using the device 10 as a switchable load in a power grid even in the absence of items to be cleaned. A second feed pump 32 allows warm fresh water to be transferred from the fresh water tank 52 to the process chamber 14 for a cleaning process, with the path of the fresh water being able to run through a dispensing compartment in the case of a washing machine in order to supply detergent.

The double-piston pump 54 is used in conjunction with a countercurrent heat exchanger 48, an inlet valve 44a and an outlet valve 66 and two check valves 72, 74 to recover heat from the waste water. An additional inlet valve 44b allows fresh water to be fed directly via an inlet line 50 of the device 10 into the insulated fresh water tank 52. The fresh water tank 52 can be filled with fresh water via the inlet valve 44b if excess electrical power is to be used to heat the water outside of a cleaning process However, fresh water tank 52 has a too low fill level.

In 8th a schematic representation of the device 10 according to the invention is shown according to a fourth exemplary embodiment, which illustrates heating of water in an external hot water storage tank 84 . A refrigerant circuit, which includes a refrigerant compressor 16, a refrigerant evaporator 20 with a fan 22 and a first heat exchanger 26, is expanded here by a second heat exchanger 80. The second heat exchanger 80 has water connections which lead to the outside through a housing 82 of the device 10 . In the refrigerant circuit of the air-to-water heat pump 12 there is a switching valve 34, through which one of the two heat exchangers 26, 80 can be selected. An external hot water tank 84 can thus be connected to the device 10 via water lines 86 and a circulating pump 88 . If the second heat exchanger 80 is selected by the changeover valve 34 and the circulating pump 88 is switched on, the device 10 can heat the contents of the hot water storage tank 84 and can thus assume the function of a heating heat pump set up in an interior space.

In particular, a hot water tank 84 can be a service water tank, for which the second heat exchanger 80 can be constructed on the water side from materials that are compatible with drinking water.

At this point it is noted that the exemplary embodiments represent two to four modifications of the device 10 of the first exemplary embodiment. With regard to exemplary embodiments two to four, only the differences from the first exemplary embodiment will be discussed in more detail and reference is made to the first exemplary embodiment with regard to all other features and functions. Accordingly, all of the features, effects and advantages disclosed with respect to the first embodiment of the device 10 may be equally applicable to the second, third and fourth embodiments of the device 10 and vice versa. Likewise, the characteristics Effects and advantages of the second, third and fourth embodiments can be applied to each other.

Finally, some further features, effects and advantages of the device according to the invention are discussed, which also relate to the exemplary embodiments one to four.

Since the device according to the invention extracts heat from the ambient air surrounding it, the room in which the device is installed inevitably cools down. Depending on the climatic zone in which the device is operated and depending on the season and weather conditions, this can be an advantage if cooling the room is desirable anyway. In geographic locations where air conditioning of interior spaces is common, this can result in an additional energy saving effect, since the room air conditioning system then has to provide less cooling capacity during operation of the device according to the invention. In cases where cooling of the installation room is not desired or the room is even heated, this is a disadvantage, especially if the room heating has to provide more heat output as a result. However, a negative heat balance due to the operation of the device according to the invention for its installation room can be avoided by not disposing of the heated process water directly via the sewage pipe after it has run through a warm cleaning process, but rather by first bringing it into thermal contact with the ambient air for a certain period of time until the water has cooled to almost room temperature, and only then is it discharged through a sewage pipe. Since electrical energy is used to heat the water with the air-water heat pump in addition to the ambient heat, it can even happen that the heat balance for the room in which the machine is installed is positively shifted and the room warms up net.

Furthermore, it can be provided that the device performs a return heat transfer from waste water, for example to the ambient air, while parallel to this, further cleaning processes are already being carried out on items to be cleaned. In particular, a heat exchanger designed as a water pocket (38) can have a sufficiently large volume of liquid to accommodate all of the waste water from a cleaning process. This allows the waste water to be pumped out quickly and another cleaning process to be carried out immediately while heat transfer from waste water to ambient air is still in progress. If cold waste water is produced in a subsequent cleaning step, it can be pumped directly into the discharge line of the device, while the not yet completely cooled waste water from a preceding warm cleaning process remains in the heat exchanger. Such direct pumping into the drain line can be realized by a bypass valve on the waste water side of a heat exchanger, so that pumping processes can be carried out, in particular after cold cleaning processes, bypassing a heat exchanger. The switching valve (34) in a previous embodiment fulfills exactly this function. As an alternative to such a valve, a second waste water pump can be provided, with the second waste water pump conveying waste water from the process chamber directly into a discharge line.

Insofar as successive cleaning processes of the device according to the invention are separated in time by several hours to days, depending on the quality of the thermal insulation of the fresh water tank, an energy saving effect can still occur through waste water heat recovery. When using a vacuum-insulated fresh water container based on the principle of a thermos flask or a Dewar flask, thermal energy can still be available to a considerable extent even after several days.

If the device according to the invention is provided with an insulated fresh water tank, the heating of water can be temporally decoupled from a cleaning process. For this purpose, the air-to-water heat pump is set up in particular to also heat the fresh water in the insulated fresh water tank instead of the process water in the process chamber. If the refrigerant condenser of the air-water heat pump is in the process chamber, the air-water heat pump can be equipped with a second refrigerant condenser, which is located in the fresh water tank, and have a switching valve within the refrigerant circuit, which selects between the two refrigerant condensers. If, on the other hand, the air-to-water heat pump works according to the continuous-flow heater principle and uses a heat exchanger (26) as the refrigerant condenser, the extended functionality can be achieved by providing a feed pump for fresh water, which pumps fresh water from the insulated fresh water tank to the heat exchanger ( 26) and back pumps. By using suitable changeover valves (34a), (34b), the feed pump can also be identical to the pump (30) which conveys water between the process chamber of the device and the refrigerant condenser.

If a state now arises in which, for example, in favor of network stability or due to the redundant availability of regeneratively generated electrical power, it is desirable to consume electrical power at a given point in time, the device according to the invention can activate the air-water heat pump and heat the fresh water in the fresh water tank even in the absence of items to be cleaned in the process chamber. In the event that the fresh water tank has a low fill level, it can be provided that it is initially filled with cold fresh water via the fresh water supply line of the device. If the fresh water reaches a specified target temperature or if additional electrical power consumption is no longer desirable, the air-water heat pump can be switched off. The fresh water heated in this way can then be stored in the fresh water tank and thus be available for the next cleaning process, which correspondingly requires less energy.

This functionality of the device according to the invention, of being able to absorb heat energy for a cleaning process at least partially in advance, before the items to be cleaned are even received in the device, allows the device to be used for demand-side management. In particular at times when renewable energy sources can supply more power overall than is consumed over a large area, a device according to the invention can provide negative control power for the public power grid. For this it is necessary that a respective power grid operator has a remote control option in the sense of a smart grid, which can be implemented, for example, via a ripple control receiver or via the Internet and requires a suitable receiving interface on the part of the device. If this technology is used across the board in around 70 million household appliances in the form of washing machines and/or dishwashers in Germany, an assumed input power of the air-water heat pump of 700 watts results in a maximum negative control power of 49 gigawatts.

Furthermore, the functionality of the device according to the invention can be particularly useful when it is located in a building that has a photovoltaic system. If the generation capacity of the local photovoltaic system exceeds the electricity consumption in the building, it can be useful to connect the device as a flexible load. For this purpose, the control electronics of the device can be equipped with a communication interface, via which the device receives control commands from a building-related energy management system. If such an energy management system is not available, the device can partially take over its task by monitoring current power flows via interfaces to an electricity meter and, if necessary, to the photovoltaic system.

Advantageously, the device according to the invention can also be equipped with a control device for throttling the electrical power consumption of the air-water heat pump and possibly also a heating element, for example with a frequency converter, phase control or high-frequency pulse width modulation. This makes it possible, if required, to also be able to use lower power surpluses, which are below the nominal power consumption of the heat pump or the heating element. Since the heating of the process water takes more time in this case than when the heat pump or the heating element is running at full power, the duration of a cleaning process can be automatically adjusted to the longer heating phase.

If the device according to the invention is set up in a building that has a thermal solar collector for heating domestic water or another scheme for heating domestic water that can heat fresh water with a lower primary energy input than the air-water heat pump of the device, it can be useful to provide the device with an additional hot water input and an electronic interface to a building-related energy management system. If warm fresh water with low energy consumption is available due to current conditions in the building, the device can draw warm fresh water from the house network and use it for warm cleaning processes. A temperature sensor at the hot water inlet can be used to set an adequate water supply. Even if a house network has service water circulation, the situation usually arises due to stationary pipe volumes that cold water initially emerges from a hot water pipe and only warm water follows after a certain amount of time has elapsed. Ideally, therefore, the initial, cold amount of water is discarded and only the subsequent warm water is used for the cleaning step.

The corresponding interface to a building-related energy management system or, if applicable, an existing Internet connection can also be used to obtain forecast data regarding the availability of regeneratively generated electrical energy or regeneratively heated fresh water and the start time of a cleaning process under ener to optimize getical aspects when there is cleaning material in the device, but with regard to the exact time of the cleaning process there is a certain flexibility on the part of the user of the device.

Since the device according to the invention most likely includes more parts or components than comparable household appliances according to today's market standard, the total weight of the device is to be expected to be higher. The additional components also require additional installation space, so that in the case of an unchanged size of the process chamber, larger device dimensions can be expected, insofar as previously unused cavities cannot be utilized. In order to temporarily reduce the weight of the device in the event of transport, provision can be made for the air-water heat pump to be removable. In particular, this property can also make it considerably easier to replace the heat pump in the course of repair work.

In the case of washing machines and dishwashers, external dimensions of around 82 cm in height, 60 cm in width and a maximum of 60 cm in depth are the usual market standard, which enables installation under worktops, particularly in kitchen units. In order to continue to be able to maintain these external dimensions despite the additional components mentioned, it can be provided that individual components of the device according to the invention are outsourced to separate housings, which are housed in adjacent containers, for example under adjacent kitchen cabinets, and connected to the device or a main unit of the Device are connected via lines. If kitchen furniture does not reach down to the floor, the resulting cavity, which is usually closed off at the front by a base panel, can be used to accommodate external components of the device.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102004023126 A1 [0006, 0007]
• EP 2096203 A1 [0006, 0007, 0008]
• DE 3609277 A1 [0007]
• DE 102014118799 A1 [0008]
• DE 202010011953 U1 [0009]
• DE 19937629 A1 [0010]
• DE 202021002165 U1 [0011]
• DE 202021002540 U1 [0011]

Claims (13)

Device (10), in particular a washing machine or dishwasher, for cleaning items to be cleaned, comprising: - A process chamber (14) which is set up to accommodate items to be cleaned; and - an air-to-water heat pump (12), the air-to-water heat pump (12) having at least one refrigerant compressor (16) for heating a refrigerant and at least one refrigerant condenser (18) for transferring the heat of the refrigerant to the items provided for cleaning the items to be cleaned has process water. Device (10) after claim 1 , wherein the air-water heat pump (12) is designed as a circulatory system (24) which comprises at least one refrigerant evaporator (20) for evaporating condensed refrigerant and at least one fan (22) for heating evaporated refrigerant by ambient air. Device (10) according to one of the preceding claims, wherein the refrigerant condenser (18) of the air-water heat pump (12) is designed as a first heat exchanger (26) and is arranged outside of the process chamber (14) to heat the process water transferred, and wherein a circulatory system (28) is provided and is adapted to promote process water from the process chamber (14) to the first heat exchanger (26) and from the first heat exchanger (26) into the process chamber (14). Device (10) according to any one of the preceding claims, further comprising a second heat exchanger which is set up to transfer heat from the process water heated by the air-to-water heat pump (12) to ambient air or to fresh water. Device (10) according to one of Claims 1 until 3 , wherein the device (10) has at least one fresh water tank (52) for storing fresh water and a water-water heat exchanger (48) which is designed to heat from the process water heated by the air-water heat pump (12). to transfer fresh water. Device (10) according to one of the preceding claims and optionally according to claim 5 , wherein the device (10) is further set up to transfer heat generated by the operation of the refrigerant compressor (16) to process water or fresh water. Device (10) according to one of the preceding claims, wherein the device (10) has at least one fresh water tank (52) for storing fresh water and comprises a switching device which is set up to selectively heat by the air-water heat pump (12). to allow the process water or heating of the fresh water in the fresh water tank (52). Device (10) after claim 7 , wherein the device (10) has control electronics for controlling the switching device and the air-water heat pump (12), wherein the control electronics comprises at least one receiving interface and is set up to heat the fresh water in the fresh water tank (52) on the basis of received control commands initiate or terminate. Device (10) after claim 5 , wherein the device (10) comprises a dual-circuit feed pump (54) which is set up to regulate a flow of process water exiting from the process chamber (14) and of fresh water. Device (10) according to one of the preceding claims, wherein the device (10) has chemical heat storage for the long-term storage of heat generated by the air-to-water heat pump (12). Device (10) according to any one of the preceding claims, wherein the device (10) is also set up to heat water from an external water storage tank (84) connected to the device via the air-water heat pump (12). Device (10) according to one of the preceding claims, wherein the device (10) also has an air-to-air heat pump for drying the items to be cleaned. Use of an air-water heat pump (12) for heating process water provided for cleaning items to be cleaned in a device (10) according to one of the preceding claims.

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