Device for providing domestic hot water

Abstract

The invention relates to a device (1) for providing domestic hot water, comprising a heat pump (20) for heating water, in particular drinking water, to a hot water temperature and thus for generating domestic hot water. The heat pump (20) includes an evaporator (21) for using a fluid as a heat source to evaporate a refrigerant, a condenser (22) for condensing the refrigerant, and a compressor (23) for compressing the refrigerant. Furthermore, the heat pump (20) has a heat pump operating mode in which the heat pump (20) provides heating power on the condenser side to heat the water to the hot water temperature.The device (1) further comprises a hot water storage tank (40) for storing domestic hot water, wherein the hot water storage tank (40) has a hot water storage volume. The heating output of the heat pump (20) in heat pump operating mode, divided by the hot water storage volume, is less than 2.5 watts per liter, preferably less than 2.15 watts per liter. The invention further relates to a method for operating such a device (1) for providing domestic hot water, in which the device (1) is operated in operating mode for at least 80% of the time each day, preferably at least 90% of the time each day, and particularly preferably continuously.

Description

Technical area

[0001] The invention relates to a device for providing domestic hot water, comprising a heat pump for heating water, in particular drinking water, to a hot water temperature and thus for generating the domestic hot water. The heat pump comprises an evaporator for using a fluid as a heat source to evaporate a refrigerant, a condenser for condensing the refrigerant, and a compressor for compressing the refrigerant, in particular a compressor for compressing the refrigerant. The heat pump has a heat pump operating mode in which the heat pump provides heating power on the condenser side to heat the water to the hot water temperature, and a hot water storage tank for storing the domestic hot water, the hot water storage tank having a hot water storage volume. The invention further comprises a method for operating such a device for providing domestic hot water. State of the art

[0002] Devices belonging to the technical field mentioned above are known. An example of such a device is described in DE 20 2014 226 983 A1 by ROTEX Heating Systems GmbH. A device of this type is known from DE 30 47 742 A1.

[0003] However, such devices have the disadvantage that they cause considerable, disturbing noise emissions during operation and are therefore only suitable to a limited extent for use in living spaces. Description of the invention

[0004] The object of the invention is to create a device belonging to the aforementioned technical field that is quiet during operation and thus generates only low noise emissions. Furthermore, the object of the invention is to create a method for the correspondingly quiet operation of such a device.

[0005] The solution to the problem is defined by the features of claim 1. According to the invention, the heating output of the heat pump in heat pump operating mode divided by the hot water storage volume is less than 2.5 watts per liter, preferably less than 2.15 watts per liter, wherein in heat pump operating mode the compressor, in particular the compressor, requires a rated compressor output for its operation, wherein the rated compressor output divided by the hot water storage volume is at most 1.4 watts per liter. The heat pump is an air-water heat pump. Accordingly, the fluid and thus the heat source is air. The device further comprises a fan for supplying air as a heat source to the evaporator, wherein with the fan, during operation of the fan at ambient pressure, an air volume of air can be supplied to the evaporator per second, wherein the speed of the air moved by the fan is less than 0.8 m / s.The device comprises an air duct through which the air volume can be supplied to the evaporator per second with the fan when the fan is operating at ambient pressure, wherein the air duct comprises an air inlet for letting in air from an environment of the device and an air outlet for letting air out into the environment of the device, wherein the air duct has a minimum cross-section, wherein the air volume divided by the minimum cross-section is less than 0.8 m, which ensures that the speed of the air moved by the fan is less than 0.8 m / s.

[0006] In the method for operating the device according to the invention, the device is operated in operating mode for at least 80% of the time of the respective day, preferably at least 90% of the time of the respective day, particularly preferably permanently. Preferably, the device is operated in this way for at least one week, i.e., seven days a day.

[0007] According to the invention, the device serves to provide domestic hot water. Domestic hot water is preferably water with a temperature in a range of 45°C to 75°C, particularly preferably in a range of 55°C to 65°C, and most preferably in a range of 60°C to 65°C. Domestic hot water is particularly preferably drinking water with a temperature in a range of 45°C to 75°C, particularly preferably in a range of 55°C to 65°C, and most preferably in a range of 60°C to 65°C. Thus, the provision of domestic hot water preferably comprises heating water, in particular drinking water, to a temperature in the range from 45°C to 75°C, in particular in the range from 55°C to 65°C or in the range from 60°C to 65°C, as well as keeping the water or drinking water ready at a temperature in the range from 45°C to 75°C, in particular in the range from 55°C to 65°C or in the range from 60°C to 65°C.In this case, keeping ready preferably means having it constantly ready for immediate use when needed. The hot water temperature to which the water or drinking water is heated is therefore preferably in the range of 45°C to 75°C, or in the range of 55°C to 65°C, or in the range of 60°C to 65°C. It is not necessary for the domestic hot water to be kept ready at the hot water temperature to which the domestic hot water is heated for its provision. Because the domestic hot water is stored in the hot water tank, the domestic hot water can also be drawn from the hot water tank at a draw-off temperature that is slightly lower than the hot water temperature. This can be the case, for example, if there is an inhomogeneous temperature distribution in the hot water tank. However, this can also be the case, for example, due to heat losses in the hot water tank.However, the withdrawal temperature is preferably also in the range from 45°C to 75°C, in particular in the range from 55°C to 65°C. The device particularly preferably complies with the SIA 385 / 1:2011 standard. This means that the withdrawal temperature at the inlet of the discharge line is preferably in the range from 55°C to 65°C or from 60°C to 65°C, depending on the use of the device.

[0008] The device preferably comprises a hot water storage tank for storing domestic hot water. The term "hot water storage tank" is preferably understood more broadly than that defined in the SIA 385 / 1:2011 standard and preferably includes water storage tanks with built-in heating surfaces and water storage tanks without built-in heating surfaces. Accordingly, the term "hot water storage tank" in this text is to be understood to include both storage water heaters according to the SIA 385 / 1:2011 standard and hot water storage tanks according to the SIA 385 / 1:2011 standard.

[0009] According to the invention, the heat pump comprises an evaporator for using a fluid as a heat source to evaporate a refrigerant. This fluid is preferably a substance that continuously deforms under the influence of shear forces. This means that the substance flows and preferably has a shear modulus of 0 N / m2 or zero. Thus, the fluid can be a gas, such as air. However, the fluid can also be a liquid, such as water or brine.

[0010] The invention offers the advantage that the heat pump can be designed in such a way that it produces only low noise emissions during operation and is correspondingly quiet. If the hot water storage tank volume is in the range of 120 to 500 liters, the device can be designed to fit in living spaces, for example, in a cupboard. Such a cupboard can be located, for example, in the kitchen, bathroom, hallway, or storage room.

[0011] Preferably, a maximum heating output of the heat pump for heating water to the hot water temperature, which the heat pump is designed to provide on the condenser side, divided by the hot water storage volume is less than 3.0 watts per liter, particularly preferably less than 2.5 watts per liter. The maximum heating output of the heat pump is advantageously the maximum output that the heat pump is designed to provide on the condenser side. Preferably, the heating output in heat pump operating mode is at least 80%, particularly preferably at least 90% of the maximum heating output of the heat pump. Very particularly preferably, the heating output in heat pump operating mode is 100% of the maximum heating output, or the heating output in heat pump operating mode is simultaneously the maximum heating output of the heat pump.

[0012] If the maximum heating output of the heat pump for heating water to the hot water temperature, which the heat pump is designed to achieve on the condenser side, divided by the hot water tank volume, is less than 3.0 watts per liter or less than 2.5 watts per liter, this has the advantage that the heat pump can be dimensioned comparatively small. This allows the device to be designed compactly. Another advantage is that the heat pump can be designed such that it only produces low noise emissions during operation, for example less than 35 dB(A) or even less than 26 dB(A). The device can therefore be designed such that it can be installed in living spaces and fit into a cupboard, for example. Such a cupboard can be located in the kitchen, bathroom, hallway or storage room, for example.

[0013] Alternatively, it is also possible that the maximum heating output of the heat pump for heating water to the hot water temperature, which the heat pump is designed to provide on the condenser side, divided by the hot water storage volume is 3.0 watts per liter or more.

[0014] The device preferably comprises a temperature sensor for determining the temperature of water in the hot water tank. This temperature sensor is particularly preferably arranged inside the hot water tank. Advantageously, the device also comprises a temperature display for displaying the temperature of the water in the hot water tank determined by the temperature sensor. The temperature display can be connected directly to the temperature sensor. If the device has a control unit for controlling the device, in particular the heat pump and any heating element present, the temperature display can also be connected to the control unit.

[0015] In one variant, however, the device does not include a temperature display.

[0016] Alternatively, the device does not include a temperature sensor for determining the temperature of water in the hot water tank.

[0017] The device preferably comprises a control unit for controlling the device, in particular the heat pump and any heating element present. If the device has a temperature sensor, the control unit is preferably connected to the temperature sensor to receive temperature signals output by the temperature sensor.

[0018] In a preferred variant, the control unit comprises an input unit for entering control parameters. Alternatively, however, it is also possible for the control unit not to comprise such an input unit.

[0019] If the device comprises a temperature display for displaying the temperature of the water in the hot water tank determined by the temperature sensor and a control unit for controlling the device, in particular the heat pump and any heating element present, with an input unit for entering control parameters, the temperature display can be integrated in the input unit or can be formed separately from the input unit.

[0020] The control unit is preferably designed such that it enables control of the device depending on the electricity tariff. For example, the control unit is preferably designed such that the heat pump is switched off when the electricity tariff is high. In a preferred variant, the control unit is designed such that any heating element that is present is switched off when the electricity tariff is high. If the electricity tariff changes depending on fixed times of day and is high at fixed times of day, the control unit can, for example, switch off the heat pump or any heating element that is present according to the time of day. If, on the other hand, the electricity tariff depends on the current electricity demand and the current electricity supply or the current electricity market, the control unit can switch off the heat pump or the heat pump if the current electricity tariff exceeds a limit value of the current electricity tariff.The limit value can be set manually or automatically. The latter can be done, for example, based on a moving average of the electricity tariff over a certain number of days, such as the past 10 days, by automatically setting the limit value to 200% of the moving average. Such electricity-tariff-dependent control options offer the advantage that the device can be designed to be smart grid-compatible. In order to receive data regarding the electricity tariff, the control device preferably comprises an interface for connecting to the internet or a mobile phone network. Alternatively, the control device can also be designed without such an interface.

[0021] As an alternative to these variants, the device does not include a control unit for controlling the device.

[0022] Advantageously, in heat pump operating mode, the compressor, in particular the compressor, requires a nominal compressor power for its operation, wherein the nominal compressor power divided by the hot water storage volume is particularly preferably at most 0.7 watts per liter, most preferably at most 0.5 watts per liter. If the compressor is an electric compressor or the compressor is an electric compressor, the nominal compressor power is preferably the nominal electrical power of the compressor or the compressor in heat pump operating mode. If the compressor or the compressor is driven by an internal combustion engine, the nominal compressor power is preferably determined by the consumption of fuel for operating the compressor orof the compressor in heat pump operating mode, the calorific value of the fuel used and the efficiency of the combustion engine, whereby the calorific value is multiplied by the amount of fuel consumed per unit of time for the operation of the compressor in heat pump operating mode and the efficiency of the combustion engine. Regardless of whether the compressor is an electric compressor or not, a compressor rating divided by the hot water tank volume of a maximum of 1.4 watts per liter, a maximum of 0.7 watts per liter or a maximum of 0.5 watts per liter has the advantage that the compressor requires comparatively little energy. The lower the value of the watts per liter, the greater the advantage. This is particularly true for an electric compressor.An electric compressor offers the advantage that the device can be powered by a comparatively small photovoltaic system. If the device is used in a residential building, such as a single-family home or an apartment building, a photovoltaic system sufficiently dimensioned to operate the device can easily be installed on the roof of the building.

[0023] Alternatively, it is also possible for the compressor's rated power divided by the hot water tank volume to be more than 1.4 watts per liter. Preferably, the device has a heating element, in particular an electric heating element, to assist the heat pump in heating water, in particular drinking water, to the hot water temperature and thus in the generation of domestic hot water. The heating element is arranged in the hot water tank. This has the advantage that the generation of domestic hot water can be optimally supported by operating the electric heating element when needed.

[0024] In a first preferred variant thereof, the device is designed for operation in an operating orientation aligned in the room, wherein in the operating orientation of the device the heating element is arranged in an upper third of the hot water tank. This has the advantage that the water, in particular drinking water, can be heated very quickly in the upper third of the hot water tank if, for example, in the case of high domestic water consumption the temperature of the water in the hot water tank drops below a limit value such as 55°C, in order to be able to quickly provide domestic hot water again or continue to be provided. In a second preferred variant thereof, the device is designed for operation in an operating orientation aligned in the room, wherein in the operating orientation of the device the heating element is arranged in the lower two-thirds of the hot water tank.This has the advantage that if the heat pump fails, the same amount of domestic hot water can still be provided as with the heat pump.

[0025] Preferably, the heating element has a heating element operating mode in which the heating element has a heating element power for heating water in the range of 5 watts per liter of hot water storage volume to 12 watts per liter of hot water storage volume, particularly preferably approximately 10 watts per liter of hot water storage volume. This has the advantage that the heating element can be dimensioned comparatively small and cost-effectively.

[0026] In a variant, the heating element can also have a different heating element operating mode.

[0027] As an alternative to the variants with a heating element, it is also possible for the device not to have such a heating element.

[0028] The device preferably has elements made of phase change material that are arranged in the hot water tank or adjacent to the hot water tank. These elements are preferably enclosed in a casing and thus separated from the water in the hot water tank. A phase change material is preferably a material whose enthalpy of fusion in joules per kilogram is greater than the energy in joules per kilogram that is required to heat one kilogram of the material in the liquid state by 10°C, particularly preferably by 50°C. The phase transition temperature of the phase change material from the liquid to the solid state is particularly preferably in a range from 45°C to 75°C, particularly preferably in a range from 55°C to 65°C, and very particularly preferably in a range from 60°C to 65°C. This has the advantage that, when there is a high consumption of domestic hot water, the temperature of the water or the solid state can be prevented from rising at least temporarily.The temperature of the drinking water in the hot water tank can fall below the phase transition temperature of the phase-change material because the phase-change material first solidifies before the temperature of the water or drinking water in the hot water tank can drop further. This allows for a higher domestic hot water consumption for a given hot water tank volume, or for a certain domestic hot water consumption to be achieved even with a smaller hot water tank volume.

[0029] Hard paraffin is particularly preferred as a phase-change material, i.e., a paraffin in which n-alkanes predominate, with a molar mass between 275 and 600 grams per mole. Hard paraffin has the advantage of being insoluble in water, which makes it easy to prevent contamination of the water in the hot water tank. The phase transition temperature of hard paraffin is approximately 60°C.

[0030] Alternatively, it is also possible that the device does not have any elements made of phase change material arranged in the hot water tank or adjacent to the hot water tank.

[0031] The device is advantageously designed for a power supply of 230V plus / minus 10% alternating current with a frequency of 50Hz and a maximum current of 10A, and can be connected to a power grid with a voltage of 230V plus / minus 10% alternating current with a frequency of 50Hz and a maximum current of 10A. This has the advantage that the device can be connected to the existing power connections in both new and old buildings. Alternatively, it is also possible for the device to be designed for a different power supply. Depending on the power supply, the voltage, frequency, or current may have different values. In a preferred variant, the device is designed for operation with a direct current supply.This is advantageous, for example, if the device is to be operated with a photovoltaic system and, if present, a power storage device, since no conversion to alternating current is required.

[0032] The heat pump is particularly preferably an electric heat pump. Accordingly, the compressor is preferably an electrically driven compressor. The heat pump is preferably designed for a power supply of 230V plus / minus 10% with alternating current at a frequency of 50Hz and a maximum current of 10A. The heat pump is particularly preferably designed for a power supply of 230V plus / minus 10% with alternating current at a frequency of 50Hz and a maximum current of 2.0A, most preferably a maximum current of 1.5A. In one variant, it is also possible for the heat pump to be designed for a different power supply. Depending on the power supply, the voltage, frequency or current can have different values. In a preferred variant, the heat pump or compressor is designed for operation with a direct current supply.This is advantageous, for example, if the device is to be operated with a photovoltaic system and, if present, a power storage unit, since no conversion to alternating current is required. Another variant, however, is the possibility of the heat pump not being an electric heat pump. In this case, the compressor can be driven by a combustion engine, for example.

[0033] The heat pump advantageously has a refrigerant circuit. In this refrigerant circuit, the condenser, the evaporator, and the compressor are arranged one after the other in the direction of refrigerant flow, followed in turn by the condenser. In a preferred variant, the heat pump also has a throttle, in particular a valve or a constriction such as a capillary in the refrigerant circuit, for reducing a pressure in the refrigerant circuit downstream of the throttle in the flow direction compared to upstream of the throttle, wherein the throttle is arranged downstream of the condenser and upstream of the evaporator in the flow direction of the refrigerant. In one variant, however, the refrigerant circuit does not have a throttle.

[0034] The refrigerant circuit is preferably a closed circuit. Alternatively, the refrigerant circuit can also be an open circuit.

[0035] The heat pump is preferably designed for operation with a refrigerant quantity that, in liquid form, occupies a volume of less than 1%, preferably less than 0.1%, and most preferably less than 0.075% of the hot water storage tank volume. This has the advantage that only a comparatively small amount of refrigerant is required. This is particularly advantageous if the refrigerant is harmful to the environment or climate.

[0036] Alternatively, it is also possible that the heat pump is designed to operate with a larger amount of refrigerant.

[0037] The heat pump preferably contains the refrigerant. The refrigerant is preferably a fluid used for heat transfer in the heat pump, which absorbs heat at low temperature and low pressure and releases heat at higher temperature and higher pressure, whereby changes in the state of the fluid occur. The changes in state of the fluid are preferably from liquid to gaseous when absorbing heat, and from gaseous to liquid when releasing heat. Examples of refrigerants are 1,1,1,2-tetrafluoroethane, carbon dioxide, ammonia, propane, 2,3,3,3-tetrafluoropropene, and water. These and other examples of refrigerants are listed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in ANSI / ASHRAE Standard 34-2016. The refrigerant propane is particularly preferred. Propane has the advantage of being practically insoluble in water and becoming gaseous at ambient pressure as low as -42.1°C.If refrigerant accidentally enters the hot water tank due to a leak, the refrigerant does not dissolve in the water in the tank, but instead becomes a gas and settles in the upper part of the tank above the water in the tank. From there, the refrigerant can be easily drained through a pressure relief valve, if present.

[0038] Alternatively, the heat pump can also be designed without a refrigerant. This can be advantageous, for example, for long-term storage or transport of the device. In this case, the refrigerant is preferably added to the heat pump before commissioning.

[0039] Advantageously, the heat pump contains the refrigerant, with the refrigerant in liquid form having a volume of less than 1%, preferably less than 0.1%, and most preferably less than 0.075% of the hot water tank volume. This has the advantage that only a comparatively small amount of refrigerant is required. This is particularly advantageous if the refrigerant is harmful to the environment or climate.

[0040] Preferably, the condenser heats the water in the hot water tank to the domestic hot water temperature. This has the advantage that the device enables particularly efficient provision of domestic hot water.

[0041] In a first preferred variant, the condenser is arranged in the hot water tank. Particularly preferably, the condenser is double-walled. In a preferred variant, however, the condenser is single-walled. However, the condenser can also be triple-walled or multi-walled. Regardless of how multi-walled the condenser is, the device is thus advantageously a storage water heater according to the SIA 385 / 1:2011 standard. In a second preferred variant, the condenser is arranged outside the hot water tank. For example, the condenser can be formed by a pipe or hose that is guided or wound around the hot water tank several times.

[0042] As an alternative to these variants, it is also possible for the condenser to heat water outside the hot water tank to the hot water temperature. This can be achieved, for example, by locating the condenser upstream of the hot water tank with respect to the direction of water flow through the device. However, this can also be achieved, for example, by having the device have a water line from the hot water tank to the condenser and back to the hot water tank, so that water from the hot water tank can be fed to the condenser for heating to the hot water temperature and, after heating, can be fed back to the hot water tank.

[0043] The device preferably has a water inlet connection for connecting the device to a water supply, in particular a drinking water supply. The water inlet connection is preferably connected to the hot water tank in order to allow water or drinking water supplied to the water inlet connection to flow into the hot water tank.

[0044] The device preferably has a water drain connection for connecting the device to a hot water consumption device, wherein the water drain connection is preferably connected to the hot water tank in order to drain domestic hot water from the hot water tank via the water drain connection and thereby supply it to a hot water consumption device that may be connected to the water drain. The water drain connection is preferably connectable to an outlet line that is connected to the hot water consumption device. Thus, if the device complies with the SIA 385 / 1:2011 standard and the withdrawal temperature at the inlet of the outlet line is in the range of 55°C to 65°C or 60°C to 65°C, depending on the use of the device, the withdrawal temperature is preferably the temperature of the water withdrawn from the hot water tank measured at the water drain connection.

[0045] The hot water storage capacity is preferably at least 150 liters, preferably at least 200 liters. This has the advantage that the device is suitable for providing domestic hot water for an apartment, as it is designed to provide domestic hot water for approximately 3 to 5 people, and thus for approximately 4 people.

[0046] The hot water storage volume is preferably no more than 1,000 liters, particularly preferably no more than 500 liters, and most particularly preferably no more than 350 liters. Alternatively, the hot water storage volume can also be more than 1,000 liters.

[0047] The heat pump is an air-to-water heat pump, meaning the fluid and thus the heat source is air. This has the advantage that ambient air can be used as the heat source, eliminating the need for separate heat source piping. This makes the device particularly easy to install. Furthermore, the device is particularly suitable for use in apartments and houses undergoing renovations, as no connection to a separate heat source is required.

[0048] The device includes a fan for supplying air as a heat source to the evaporator. This has the advantage that more air can be supplied to the evaporator, thus allowing a larger amount of heat source to be supplied, from which the heat pump can extract energy per unit of time. This increases the heating output that the heat pump provides on the condenser side in heat pump mode to heat the water to the domestic hot water temperature.

[0049] Preferably, when the fan is operating at ambient pressure, the air volume per second can be supplied to the evaporator, whereby the air volume per second is at least 0.142 liters per second per watt of heating output of the heat pump in heat pump operating mode. Applied to an example in which the heating output of the heat pump in heat pump operating mode is 480 watts, when the fan is operating at ambient pressure, the air volume per second can be supplied to the evaporator which is at least 68.16 liters per second. In this example, the hot water storage tank volume can be 200 liters and the heating output of the heat pump in heat pump operating mode divided by the hot water storage tank volume can be 2.4 watts per liter. In the same way, in this example the hot water storage tank volume can also be 250 liters and the heating output of the heat pump in heat pump operating mode divided by the hot water storage tank volume can be 1.92 watts per liter.

[0050] An air volume per second of at least 0.142 liters per second per watt of heat pump heating output in heat pump mode has the advantage that the air in the air stream is cooled by a maximum of 5 degrees as it passes through the evaporator. This is particularly advantageous when the device is used in living spaces, as it prevents an unpleasantly cold air stream from being created in the living space. Alternatively, it is also possible to use the fan to supply an air volume per second to the evaporator at ambient pressure when the fan is operating at ambient pressure, which is less than 0.142 liters per second per watt of heat pump heating output in heat pump mode.

[0051] Preferably, the fan can supply a volume of air per second to the evaporator during operation at ambient pressure, wherein the air volume per second divided by the hot water storage volume is at least 0.284 per second, particularly preferably at least 0.355 per second. In a variant, however, the air volume per second divided by the hot water storage volume can also be less than 0.284 per second.

[0052] When the fan is operating at ambient pressure, a volume of air can be supplied to the evaporator per second with the fan moving at a speed of less than 0.8 m / s. This has the advantage that flow noise from the air moved by the fan is minimized. Accordingly, the device causes only low noise emissions and is therefore suitable for use in living spaces. The device comprises an air duct through which a volume of air can be supplied to the evaporator per second with the fan when the fan is operating at ambient pressure, the air duct comprising an air inlet for letting in air from an area surrounding the device and an air outlet for letting air out into the area surrounding the device, the air duct having a minimum cross-section, the air volume divided by the minimum cross-section being less than 0.8 m.This has the advantage of ensuring in a simple way that the speed of the air moved by the fan is less than 0.8 m / s.

[0053] By comprising a fan for supplying air as a heat source to the evaporator, wherein the fan can supply an air volume of air per second to the evaporator at ambient pressure when the fan is operating, wherein a speed of the air moved by the fan is less than 0.8 m / s and wherein the air volume per second is at least 0.142 litres per second per watt of heating output of the heat pump in heat pump operating mode, it is ensured that flow noise of the air moved by the fan is minimised and that the air in the air stream is cooled by a maximum of 5 degrees when passing through the evaporator.

[0054] The fan is preferably designed for a power supply of 230V plus / minus 10% with alternating current at a frequency of 50Hz and a maximum current of 0.25 A.

[0055] Preferably, the fan is mounted in the device in a sound-decoupled manner. Alternatively, it is also possible for the fan to be mounted in the device in a non-sound-decoupled manner. Preferably, the compressor is mounted in the device in a sound-decoupled manner. Alternatively, it is also possible for the compressor to be mounted in the device in a non-sound-decoupled manner. Particularly preferably, both the fan and the compressor are mounted in the device in a sound-decoupled manner. Preferably, both the fan and the compressor are mounted on the rest of the device with a bearing. However, it is also possible for neither the fan nor the compressor to be mounted in the device in a sound-decoupled manner.

[0056] In these variants, sound-decoupled mounting preferably means that the object in question, such as the fan or compressor, is mounted on the rest of the device with a bearing in such a way that vibrations of the object generated during operation are transmitted from the bearing to the rest of the device in a reduced manner. Measured across the entire vibration frequency spectrum, the vibrations measured on a side of the bearing facing away from the object are preferably at least 30%, particularly preferably at least 50%, lower than those measured on a side of the bearing facing the object. Such sound-decoupled mounting can be achieved, for example, using rubber elements.With such a suitable sound-insulated mounting, the device can be achieved with a noise emission (A-weighted sound power level according to DIN EN 61672-1 2003-10) of no more than 35 dB(A), preferably no more than 25 dB(A), when the heat pump is operating in heat pump mode. This makes the device no louder than a refrigerator commonly used in 2018 and therefore suitable for installation in a living space.

[0057] Instead of the invention, the heat pump can be a water-to-water heat pump, and thus the fluid and thus the heat source can be water. This has the advantage that the heat source has a high specific heat capacity. As a result, the heat pump requires a comparatively small amount of heat source per unit of time and can still extract a comparatively large amount of energy from this amount of heat source. As a result, the heating output that the heat pump provides on the condenser side in heat pump operating mode to heat the water to the hot water temperature is comparatively high for a given heat source consumption.

[0058] If the heat pump is a water-water heat pump, the device preferably comprises a heat source water line with two heat source water connections for connecting the device to a heat source water supply, in particular a heating circuit or a fresh water source, in order to conduct water as a heat source to the evaporator and away from the evaporator again.

[0059] Furthermore, instead of the invention, the heat pump can be a brine-water heat pump, and thus the fluid and thus the heat source can be a brine. A brine is preferably an aqueous solution of salts containing at least 14 g of dissolved salts per kg of water. This has the advantage that the

[0060] The device can be connected, for example, to the geothermal probe of a geothermal heating system.

[0061] Preferably, the device includes thermal insulation of the hot water tank. This has the advantage of minimizing heat losses from the water stored in the hot water tank, especially domestic hot water.

[0062] The thermal insulation is preferably an insulating layer that encloses at least 95%, particularly preferably at least 99%, of the outer surface of the hot water tank. The insulating layer is preferably applied directly to the outer surface of the hot water tank and is thus a component of the hot water tank. However, the insulating layer can also be arranged at a distance from the outer surface of the hot water tank. For example, the insulating layer can be arranged on a housing of the device, if present.

[0063] The device advantageously includes a housing. This has the advantage of optimally protecting the device's components from harmful external influences. It also has the advantage of making access to potentially dangerous components of the device, such as any power supply or hot elements, more difficult. Especially when the device is installed in living spaces, this has the advantage of easily minimizing the risk of accidents.

[0064] If the heat pump is an air-to-water heat pump and thus the fluid and thus the heat source is air, the housing preferably has an air inlet for admitting air as a heat source into the housing and an air outlet for admitting air from the housing. The device is preferably designed for operation in an operating orientation in the room, wherein in the operating orientation of the device the air inlet is arranged at the bottom and the air outlet at the top in the housing. This has the advantage of preventing unpleasant cool air currents near the floor. This is particularly advantageous when the device is arranged in living spaces. In a preferred variant, in the operating orientation of the device the air inlet is arranged at the top and the air outlet at the bottom in the housing.Since the air is used as a heat source and is cooled accordingly during operation of the device, the cooled air, by convention, descends from the air inlet to the air outlet during operation. Thus, the air and thus heat source supply to the evaporator is supported if the air inlet is located at the top and the air outlet at the bottom of the housing. This eliminates the need for an additional fan to supply air as a heat source to the evaporator, or at least allows the fan to be smaller and less noisy. This reduces the device's noise emissions.

[0065] As an alternative to the two preferred variants mentioned above, the air inlet and the air outlet can also be arranged elsewhere in the housing.

[0066] Preferably, the device is designed for operation in a spatially aligned operating orientation, with the compressor, in particular the compressor, being arranged below the hot water tank in the operating orientation of the device. This has the advantage that the compressor causes fewer vibrations in the rest of the device, and in particular in the hot water tank, during operation. This reduces the noise emissions of the device.

[0067] In one variant, the compressor is positioned above the hot water tank in the device's operating orientation. In another variant, the compressor is positioned at the same height as the hot water tank in the device's operating orientation.

[0068] The device is preferably a tall cabinet boiler. A tall cabinet boiler is preferably a hot water storage tank with a heating device for heating the water, in this case the heat pump, and possibly a heating element to support the heat pump. The device or tall cabinet boiler is designed for operation in an operating orientation within the room, with the tall cabinet boiler having a maximum width of 549 mm, a maximum depth of 549 mm, and a maximum height of 2399 mm in the operating orientation. This has the advantage that the tall cabinet boiler complies with the former Swiss SINK standard, which corresponds to the "Swiss Mass System" (SMS) valid in 2018, and can therefore be easily installed in an existing building, such as a corridor, kitchen, bathroom, or storage room.In a variant, however, there is also the possibility that the tall cabinet boiler has different dimensions.

[0069] Regardless of whether the device is a tall cabinet boiler or not, the device preferably has a front side. If the device comprises a control unit for controlling the device, in particular the heat pump, wherein the control unit comprises an input unit for entering control parameters, this input unit is preferably arranged on the front side of the device. If the device comprises a temperature sensor for determining the temperature of the water in the hot water tank and a temperature display for displaying the temperature of the water in the hot water tank determined by the temperature sensor, the temperature display is preferably arranged on the front side of the device. It is irrelevant whether the temperature display is integrated into the input unit, if present, or is formed separately from the input unit, if present.If the device is a tall cabinet boiler, the tall cabinet boiler preferably has a rear wall which is located on a side of the device opposite the front of the device.

[0070] If the device has a front and includes a fan for supplying air to the evaporator, the fan is preferably positioned behind the evaporator as viewed from the front of the device. This has the advantage of reducing the device's noise emissions during operation. In a variant, however, the fan can also be positioned in front of the evaporator as viewed from the front of the device.

[0071] Further advantageous embodiments and combinations of features of the invention emerge from the following detailed description and the entirety of the patent claims. Short description of the drawings

[0072] The drawings used to explain the embodiment show: Fig. 1 is a simplified schematic representation of a side view of a first device according to the invention for providing domestic hot water with an air-water heat pump and a hot water storage tank, in which a condenser of the heat pump is arranged in the hot water storage tank, Fig. 2 is a simplified schematic representation of a side view of a second device according to the invention for providing domestic hot water, in which the condenser of the heat pump is not arranged in the hot water storage tank, but is designed as a pipe wound around the hot water storage tank, in which the coolant is contained, and Fig. 3 is a simplified schematic representation of a side view of a third device for providing domestic hot water with a water-water heat pump. In principle, identical parts in the figures are provided with identical reference symbols. Ways to implement the invention

[0073] Figure 1 shows a simplified schematic representation of a side view of a first device 1 according to the invention for providing domestic hot water. Device 1 is a tall cabinet boiler with a width of 549 mm, a depth of 549 mm, and a height of 2399 mm, thus complying with the former Swiss SINK standard, which corresponds to the "Swiss Measurement System" (SMS) valid in 2018.

[0074] The device 1 is designed for operation in an operating orientation in space. Accordingly, the device 1 is in the Figure 1 shown aligned in the operating orientation. This means that in the Figure 1Top and bottom also apply to device 1 when aligned in the operating orientation. Furthermore, the previous information regarding the height of the tall cabinet boiler refers to the height of the tall cabinet boiler when aligned in the operating orientation of device 1. Due to this representation, the following references to the height of device 1 in the operating orientation are made with terms such as "below," "below," "top," and "above."

[0075] As already mentioned, the Figure 1 a side view of the device 1. Therefore, the depth of the device 1 extends in the Figure 1 from left to right. This means that on the left in the Figure 1 a front side of the device 1, while on the right in the Figure 1 a rear side of the device 1 opposite the front side of the device 1. In this case, Figure 1only a vertical section through the front and a vertical section through the back of the device 1 are visible, because the front and the back of the device 1 are each arranged in a plane which is perpendicular to the plane of representation of the Figure 1 are aligned.

[0076] The device 1 comprises an enclosing housing 60. The device 1 further comprises a hot water tank 40 arranged in the housing 60 for storing domestic hot water. This hot water tank 40 has a hot water storage volume of 200 liters. However, this hot water storage volume can also be larger or smaller. For example, it can be 120 liters, 150 liters, or even 250 liters, 300 liters, 350 liters, 500 liters, 1,000 liters, or more. Regardless of the hot water storage volume, the device 1 has thermal insulation 45 of the hot water tank 40. This thermal insulation 45 is an insulating layer that is applied to an outer surface of the hot water tank 40 and is thus a component of the hot water tank 40 and reduces heat losses of the domestic hot water stored in the hot water tank 40. The thermal insulation covers 99% of the outer surface of the hot water tank 40.

[0077] Regardless of the hot water tank volume, the device 1 has a water inlet connection 43 for connecting the device 1 to a drinking water supply (not shown here). This water inlet connection 43 is connected to a lower region of the hot water tank 40 in order to supply drinking water supplied to the water inlet connection 43 to the hot water tank 40 in the lower region of the hot water tank 40. Furthermore, the device 1 has a water outlet connection 44 for connecting the device 1 to a hot water consumption device (not shown here), wherein the water outlet connection 44 is connected to an upper region of the hot water tank 40 in order to drain domestic hot water from the hot water tank 40 via the water outlet connection 44 and thereby supply it to a hot water consumption device that may be connected to the water outlet.For this purpose, the water drain connection 44 can be connected to an outlet line not shown here, which is connected to the hot water consumption device.

[0078] In addition to the hot water tank 40, the device 1 comprises a heat pump 20 arranged in the housing 60 for heating drinking water to a hot water temperature of 62°C and thus for generating domestic hot water, which can be stored in the hot water tank 40. This heat pump 20 comprises an evaporator 21 for using a fluid as a heat source to evaporate a refrigerant. The heat pump 20 further comprises a condenser 22 for condensing the refrigerant, a compressor 23 for compressing the refrigerant, and a throttle 24. The compressor 23 is an electrically operated compressor for compressing the refrigerant. Since the compressor is electrically operated, the compressor 23 is an electric compressor and the heat pump 20 is an electric heat pump.

[0079] The heat pump 20 has a closed-loop refrigerant circuit 25. Arranged in this refrigerant circuit 25 in the direction of refrigerant flow are the condenser 22, the throttle 24, the evaporator 21, and the compressor 23, followed in turn by the condenser 22. The refrigerant contained in the refrigerant circuit 25 is propane. In variations, the refrigerant circuit 25 can also contain a different refrigerant, such as 1,1,1,2-tetrafluoroethane. Examples of other possible refrigerants are listed in ANSI / ASHRAE Standard 34-2016 of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

[0080] In a first variant, the heat pump 20 is designed for operation with a quantity of refrigerant which, in liquid form, occupies a volume of less than 1% of the hot water storage volume. In the previously mentioned embodiment, where the hot water storage volume is 200 liters, in one example the quantity of refrigerant is 1.9 liters, which corresponds to 0.95% of the hot water storage volume. In a second variant, the heat pump 20 is designed for operation with a quantity of refrigerant which, in liquid form, occupies a volume of less than 0.1% of the hot water storage volume. In the previously mentioned embodiment, where the hot water storage volume is 200 liters, in one example the quantity of refrigerant is 0.19 liters, which corresponds to 0.095% of the hot water storage volume.In a third variant, the heat pump 20 is designed for operation with a refrigerant quantity that, in liquid form, occupies a volume of less than 0.075% of the hot water storage volume. In the previously mentioned embodiment, where the hot water storage volume is 200 liters, the refrigerant quantity is 0.148 liters, which corresponds to 0.074% of the hot water storage volume. In all of these variants and examples, the heat pump 20 contains the stated amount of refrigerant.

[0081] The heat pump 20 has a heat pump operating mode in which the heat pump 20 can be operated. In this heat pump operating mode, the heat pump 20 provides heating power on the condenser side to heat the drinking water to the hot water temperature in order to generate domestic hot water. In the aforementioned embodiment, where the hot water storage volume is 200 liters, the heating power on the condenser side in heat pump operating mode is 480 watts in one example and 390 watts in another example. This corresponds to 2.4 watts per liter of hot water storage volume or 1.95 watts per liter of hot water storage volume. In a variant with a hot water storage volume of 300 liters, this corresponds to 1.6 watts per liter of hot water storage volume or 1.3 watts per liter of hot water storage volume. Since, according to the invention, the heating power of the heat pump 20 in heat pump operating mode divided by the hot water storage volume is less than 2.5 watts per liter, preferably even less than 2.15 watts per liter, the condenser-side heating output of the heat pump 20 in heat pump operating mode in other variants with a hot water storage volume of 120 liters is only 290 watts or only 235 watts, and in other variants with a hot water storage volume of 150 liters it is only 370 watts or only 290 watts. In these cases, this corresponds to a heating output of 2.42 watts per liter of hot water storage volume, 1.96 watts per liter of hot water storage volume, 2.47 watts per hot water storage volume, or 1.93 watts per liter of hot water storage volume. In another variant with a hot water storage volume of 1,000 liters, however, the condenser-side heating output of the heat pump 20 in heat pump operating mode is 1,500 watts, which corresponds to 1.5 watts per liter of hot water storage volume.What all of these variants and examples have in common is that the condenser-side heating output of the heat pump 20 in heat pump operating mode, divided by the hot water storage volume, is less than 2.5 watts per liter of hot water storage volume. In some of the aforementioned variants, the condenser-side heating output of the heat pump 20 in heat pump operating mode, divided by the hot water volume, is even less than 2.15 watts per liter of hot water storage volume. In both cases, the heat pump 20 is dimensioned such that its heating output in heat pump operating mode is 85% of its maximum heating output. In other variants, the heat pump 20 is dimensioned such that its heating output in heat pump operating mode is its maximum heating output.

[0082] In heat pump operating mode, the compressor 23 requires a rated compressor power for its operation. In a first variant, this rated compressor power is a maximum of 1.4 watts per liter of the hot water storage volume. In a second variant, the rated compressor power is a maximum of 0.7 watts per liter of the hot water storage volume. In a third variant, however, the rated compressor power is a maximum of 0.5 watts per liter of the hot water storage volume. In the embodiment already described, where the hot water storage volume is 200 liters and the condenser-side heating output of the heat pump 20 in heat pump operating mode is 480 watts, the rated compressor power in the first variant is 280 watts. In the second variant, however, the rated compressor power is 140 watts, while in the third variant it is 100 watts.Both the compressor 23 and the evaporator 21, as well as the throttle 24 of the heat pump 20, are arranged below the hot water tank 40. As a result, vibrations generated by the heat pump 20 in operating mode are only minimally transmitted to the hot water tank 40. Accordingly, the device 1 generates only low noise emissions during operation. The condenser 22, on the other hand, is arranged in the hot water tank 40 in order to heat the drinking water in the hot water tank 40 to the hot water temperature. This enables efficient heat transfer to the drinking water in the hot water tank 40 to heat the drinking water to the hot water temperature. The condenser has a double-walled design so that in the event of a leak in the refrigerant circuit 25, refrigerant cannot inadvertently enter the drinking water in the hot water tank 40.Even if the condenser 22 is arranged in the hot water tank 40, the arrangement of the remaining components of the heat pump 20 below the hot water tank 40 means that the heat pump 20 is arranged below the hot water tank 40.

[0083] In the front of the housing 60 of the device 1, an air inlet 61 is arranged in a lower region of the housing 60 and an air outlet 62 is arranged in an upper region of the housing 60. The air inlet 61 is connected to the air outlet 62 by an air duct 63. This air duct 63 is in the Figure 1shown with dashed lines. It runs from the air inlet 61 below the hot water tank 40 towards the rear of the device 1 and upwards in the area of ​​the rear of the device 1 as well as above the hot water tank 40 to the air outlet 62. The evaporator 21 of the heat pump 20 is arranged in the air duct 63 below the hot water tank 40. In addition, a fan 30 is arranged on the side of the evaporator 21 opposite the air inlet 61. The fan 30 moves ambient air through the air inlet 61 and the air duct 63 to the evaporator 21 and further to the air outlet 62 and back into the environment. As a result, the evaporator 21 is supplied with air as a heat source during operation of the device 1. Thus, the heat pump 20 is an air-water heat pump and the fluid that serves as a heat source for the heat pump 20 is air or ambient air, which is moved through the air duct 63 by the fan 30 during operation.When the device 1 is operating with the fan 30 at ambient pressure, i.e., approximately 1,000 mbar, an air volume per second can be supplied to the evaporator 21. This air volume per second, divided by the hot water storage volume, is at least 0.142 per second per watt of heating output of the heat pump 20 in heat pump operating mode, so that the air in the air volume is cooled by a maximum of 5 degrees. In the embodiment already described, where the hot water storage volume is 200 liters, this air volume per second is thus at least 28.4 liters per second per watt of heating output of the heat pump 20 in heat pump operating mode. In the aforementioned variant, where the heating output of the heat pump 20 in heat pump operating mode is 480 watts, the air volume per second is thus at least 68.16 liters per second. In one example of this variant, the air volume per second is 71 liters per second. This is 0 per liter of hot water storage volume.355 per second. In the aforementioned variant, however, where the heating output of heat pump 20 in heat pump mode is 390 watts, the air volume per second is at least 55.38 liters per second. In an example of this variant, the air volume per second is 56.8 liters per second. This is 0.284 per second per liter of hot water tank volume. However, it is also possible that the air volume per second moved by fan 30 is larger or smaller.

[0084] At the Figure 1In the device 1 shown, the cross-section of the air duct 63 is 15 cm x 50 cm over the entire length of the air duct 63. In the example mentioned in the previous paragraph, where the volume of air per second that can be supplied to the evaporator 21 by the fan 30 at ambient pressure, i.e., approximately 1,000 mbar, is 71 liters per second, the air in the air duct is thus moved at a flow velocity of 0.947 m / s. In a variant where the cross-section of the air duct 63 is 18 cm x 50 cm over the entire length of the air duct 63, however, a flow velocity of 0.789 m / s results in the air duct 63. In a further variant, however, where the cross-section of the air duct 63 is 15 cm x 50 cm over the entire length of the air duct 63 and where the air volume that can be supplied to the evaporator 21 by the fan 30 at ambient pressure, ie about 1,000 mbar, is 56.8 liters per second, the air in the air duct is moved at a flow velocity of 0.7573 m / s.By setting the flow velocity below 0.8 m / s, flow noise is prevented from becoming audible. This reduces the noise emissions of device 1 during operation.

[0085] In order to further reduce noise emissions from device 1 during operation, both the compressor 23 and the fan 30 are mounted on the rest of the device 1 in a sound-decoupled manner by means of rubber elements. The rubber elements for mounting the compressor 23 and the compressor are dimensioned such that vibrations generated by the compressor 23 and the compressor during operation are transmitted to the rest of the device 1 in a reduced manner. Measured across the entire vibration frequency spectrum, the vibrations on a side of the rubber elements facing away from the compressor 23 and the compressor are at least 50% lower than those measured on a side of the rubber elements facing towards the compressor 23 and the compressor.For the mounting of the fan 30, the rubber elements are dimensioned such that vibrations of the fan 30 generated during operation are transmitted to the rest of the device 1 in a reduced manner. Measured across the entire vibration frequency spectrum, the vibrations measured on the rubber elements on a side of the rubber elements facing away from the fan 30 are at least 50% lower than those measured on the rubber elements on a side of the rubber elements facing the fan 30.

[0086] In addition to the components already mentioned, the device 1 comprises a temperature sensor 41 for determining the temperature of the drinking water in the hot water tank 40. This temperature sensor 41 is arranged in the hot water tank 40. Furthermore, the device 1 has an electric heating element 42 arranged in the hot water tank 40 to support the heat pump 20 in heating the drinking water to the hot water temperature and thus in the production of domestic hot water. In the Figure 1In the device 1 shown, this heating element 42 is located in the operating orientation of the device 1 in an upper third of the hot water tank 40. This allows the drinking water in the upper third of the hot water tank 40 to be heated very quickly when, in the event of high domestic water consumption, the temperature of the drinking water in the hot water tank 40 drops below a limit value, such as 55°C, in order to be able to quickly provide domestic hot water again or continue to do so. In a variant of this, in the operating orientation of the device 1, the heating element 42 is arranged in the lower two-thirds of the hot water tank 40. This means that, in the event of a failure of the heat pump 20, domestic hot water can also be provided using the heating element 42 alone.Both in the variant where the heating element 42 is arranged in the upper third of the hot water tank 40 and in the variant where the heating element 42 is arranged in the lower two-thirds of the hot water tank 40, the heating element 42 has a heating element operating mode in which the heating element 42 provides a heating element output for heating the drinking water. This heating element output is 10 watts per liter of hot water tank volume. In the previously described embodiment, where the hot water tank volume is 200 liters, the heating element output of the heating element 42 in the heating element operating mode is thus 2000 watts.

[0087] Elements 46.1, 46.2, and 46.3 made of hard paraffin, a phase-change material, are arranged in the hot water tank 40. These elements are enclosed in a shell, thus separating them from the water in the hot water tank 40. The hard paraffin material used has a phase transition temperature, or melting point, of 61°C.

[0088] To supply the device 1 with energy for operating the device 1 and in particular for operating the heat pump 20 in heat pump operating mode and for operating the heating element 42 in heating element operating mode, the device is designed for a power supply of 230V plus / minus 10% with alternating current at a frequency of 50Hz. In an embodiment where the hot water storage volume is 200 liters and the condenser-side heating output of the heat pump 20 in heat pump operating mode is 480 watts and the heating element output of the heating element 42 in heating element operating mode is thus 2000 watts, a current of less than 10 A is sufficient to operate the device 1. Accordingly, this embodiment is also suitable for use in buildings with power grids of 230V plus / minus 10% with alternating current at a frequency of 50Hz and a maximum current of 10 A.A large number of existing old buildings in Switzerland in 2018 have such a power grid. Thus, the aforementioned design is suitable for use in these old buildings.

[0089] The device 1 further comprises a control unit 10 for controlling the device 1. This control unit 10 is arranged on the front of the device 1 and is connected to the temperature sensor 41 in order to receive temperature signals output by the temperature sensor 41. Furthermore, the control unit 10 is connected to the heat pump 20, in particular to the compressor 23 of the heat pump 20, in order to control the heat pump 20 and the compressor 23. Furthermore, the control unit 10 is connected to the fan 30 for controlling the fan 30 and to the heating element 42 for controlling the heating element 42. In order to control these elements of the device 1, the control unit 10 comprises an input unit 11 for entering control parameters and a display 12 for displaying the control parameters. This display 12 also serves as a temperature display for displaying the temperature signals output by the temperature sensor 41.In addition, the control unit 10 comprises an Internet connection for receiving data, in particular data on the current electricity tariff, via the Internet.

[0090] Figure 2 shows a simplified schematic representation of a side view of a second device 101 according to the invention for providing domestic hot water. Figure 2 the same view of the device 101 is shown as Figure 1 from the device 1. Most of the features of the Figure 2 The device 101 shown are identical to the features of the device shown in Figure 1 device shown 1. The only differences are highlighted below.

[0091] In contrast to Figure 1 The device 1 shown in Figure 2In the device 101 shown, the condenser 122 of the heat pump 120 is not arranged in the hot water tank 140, but rather is designed as a tube wound around the hot water tank 140, in which the refrigerant is contained. Furthermore, the heating element 142 is not arranged in the upper third, but in the lower two-thirds of the hot water tank 140.

[0092] Both the Figure 1 Device 1 shown as well as the device in Figure 2 Both the device 101 shown can be modified so that the respective heat pump 20, 120 is no longer an air-water heat pump, but rather a water-water heat pump or a brine-water heat pump. In such modifications, the evaporator no longer uses air, but rather water or brine as the heat source.

[0093] Figure 3 shows a simplified schematic representation of a side view of a third device 201 for providing domestic hot water. Figure 3the same view of the device 201 is shown as Figure 1 from the device 1. Most of the features of the Figure 3 The device 301 shown are identical to the features of the device shown in Figure 1 device shown 1. The only differences are highlighted below.

[0094] In contrast to Figure 1 The device 1 shown is the heat pump 220 of the Figure 3 The device 201 shown is a water-water heat pump, whereby the fluid and thus the heat source is water. Therefore, the evaporator 221 of the device shown in the Figure 3The device 201 shown does not have an air supply, but rather a water supply. Accordingly, the device 201 does not require an air inlet, air duct, or air outlet. Furthermore, the device 201 also does not require a fan. Instead, however, the device 201 includes a heat source water line 226 with two heat source water connections 227.1, 227.2 for connecting the device 201 to a heat source water supply (not shown here), such as a heating circuit, in particular the heating circuit of an underfloor heating system, or a fresh water source. This heat source water line 226 serves to supply the evaporator 221 of the heat pump 220 with water as a heat source.

[0095] In one variant, the heat pump is the Figure 3The device 201 shown is a brine-water heat pump, and thus the fluid and thus the heat source is brine. In this case, the heat source water line with the heat source water connections is a brine line with two brine connections for connecting the brine line to a brine circuit, such as a geothermal probe of a geothermal heating system.

[0096] In the aforementioned variants with a hot water storage volume of 350 liters or less, the device generates a noise emission (sound power level A-weighted according to DIN EN 61672-1 2003-10) of less than 25 dB(A) when operated with the heat pump in heat pump operating mode.

[0097] The invention is not limited to the aforementioned embodiments. For example, it is not necessary for the compressor and any fan to be arranged below the hot water tank. For example, only the compressor can be arranged below the hot water tank, while the fan is arranged above the hot water tank. The compressor can also be arranged above the hot water tank or at the same height as the hot water tank. It is irrelevant whether the fan, if present, is arranged above or below the hot water tank or at the same height as the hot water tank. Furthermore, it is not necessary for the device to be a tall cabinet boiler and to have the corresponding external dimensions. The device can therefore also be larger or smaller, wider, narrower, deeper, less deep or higher orbe less sophisticated. Furthermore, the device does not require an enclosing housing. For example, the device can also be designed to provide domestic hot water in a single-family home, where it is located in the basement. However, the device can also be designed for the central provision of domestic hot water in an apartment building. The device can also be designed for use in any other building.

[0098] In summary, a device for providing domestic hot water is created that is quiet during operation and therefore generates only low noise emissions. Furthermore, a method for correspondingly quiet operation of such a device is created.

Claims

1. Apparatus (1, 101) for providing domestic hot water, comprising a. a heat pump (20, 120) for heating water, in particular drinking water, to a warm water temperature and thus for producing the domestic hot water, wherein the heat pump (20, 120) comprises an evaporator (21) for utilizing a fluid as a heat source for evaporating a refrigerant, a condenser (22, 1 22) for condensing the refrigerant and a compactor (23) for compressing the refrigerant, in particular a compressor for compressing the refrigerant, and has a heat pump operating mode in which the heat pump (20, 120) provides heat power on the side of the condenser for heating the water to the warm water temperature, and b. a warm water storage (40, 140) for storing the domestic hot water, the warm water storage (40, 140) having a warm water storage volume, wherein the heat power of the heat pump (20, 120) in the heat pump operating mode divided by the warm water storage volume is less than 2.5 watts per liter, preferably less than 2.15 watts per liter, characterized in that that in the heat pump operating mode, the compactor (23), in particular the compressor, requires a compactor nominal power for its operation, wherein the compactor nominal power divided by the warm water storage volume is at most 1.4 watts per liter, the heat pump (20, 120) is an air-water heat pump and thus the fluid and thus the heat source is air, the apparatus (1, 101) comprising a fan (30) for supplying air as a heat source to the evaporator (21), wherein, with the fan (30) in operation at ambient pressure, the evaporator (21) can be supplied per second with an air volume of air, wherein a speed of the air moved by the fan is less than 0.8 m / s, the apparatus (1, 101) comprising an air channel (63) through which, when the fan (30) is operating at ambient pressure, the air volume air can be supplied per second to the evaporator (21) by the fan (30), the air channel (63) comprising an air inlet (61) for letting in air from an ambient of the apparatus (1, 1 01) and an air outlet (62) for discharging air into the ambient of the apparatus (1, 101), the air channel (63) having a minimum cross section, wherein the air volume divided by the minimum cross section is less than 0.8 m, thus ensuring that the speed of the air moved by the fan (30) is less than 0.8 m / s.

2. Apparatus (1, 101) according to claim 1, characterized in that in the heat pump operating mode, the compactor (23), in particular the compressor, requires a compactor nominal power for its operation, wherein the compactor nominal power divided by the warm water storage volume is at most 0.7 watts per liter, particularly preferably at most 0.5 watts per liter.

3. Apparatus (1, 101) according to claim 1 or 2, characterized in that the apparatus (1, 101) has a heating element (42, 142), in particular an electric heating element, for assisting the heat pump (20, 120) in heating water, in particular drinking water, to the warm water temperature and thus in the production of domestic hot water, wherein the heating element (42, 142) is arranged in the warm water storage (40, 140).

4. The apparatus (1, 101) according to claim 3, characterized in that the heating element (42, 142) has a heating element mode of operation in which the heating element (42, 142) has a heating element power for heating water in the range of 5 watts per liter of warm water storage volume to 12 watts per liter of warm water storage volume, particularly preferably about 10 watts per liter of warm water storage volume.

5. An apparatus (1, 101) according to one of claims 1 to 4, characterized in that the heat pump (20, 120) contains the refrigerant, wherein the refrigerant in liquid form has a volume of less than 1%, preferably less than 0.1%, very particularly preferably less than 0.075% of the warm water storage volume.

6. Apparatus (1, 101) according to one of claims 1 to 5, characterized in that water in the warm water storage (40, 140) is heatable to the warm water temperature by the condenser (22, 122).

7. Apparatus (1, 101) according to one of Claims 1 to 6, characterized in that the warm water storage volume is at least 150 liters, preferably at least 200 liters.

8. Apparatus (1, 101) according to one of Claims 1 to 7, characterized in that the apparatus (1, 101) includes a thermal insulation (45) of the warm water storage tank (40, 140).

9. Apparatus (1, 101) according to any one of claims 1 to 8, characterized in that the apparatus (1, 101) comprises a housing (60).

10. Apparatus (1, 101) according to one of claims 1 to 9, characterized in that the apparatus (1, 101, 201) is designed to be aligned in space in an operation orientation, wherein in the operating orientation of the apparatus (1, 101), the compactor (23), in particular the compactor, is arranged below the warm water storage (40, 140).

11. Apparatus (1, 101) according to one of Claims 1 to 10, characterized in that the apparatus (1, 101) is a tall cupboard boiler.

12. Apparatus (1, 101) according to claim 11, characterized in that the apparatus (1, 101) is designed to be aligned in space in an operation orientation and, in the operation orientation, has a width of at most 549 mm and a depth of at most 549 mm as well as a height of at most 2399 mm.

13. Method for operating an apparatus (1, 101) for providing domestic hot water according to one of claims 1 to 12, characterized in that the apparatus (1, 101) is operated in the operating mode at least 80% of the time of the respective day, preferably at least 90% of the time of the respective day, particularly preferably permanently.

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