Efficient fresh water station and use of a fresh water station

Abstract

Fresh water station (1) for providing hot drinking water, in particular for an apartment, wherein the fresh water station (1) comprises a heat exchanger (2), wherein the heat exchanger (2) has a drinking water inlet (3) and a drinking water outlet (4), wherein the heat exchanger (2) comprises a flow inlet (5) and a return outlet (6) for a temperature control medium, wherein the fresh water station (1) comprises an electric instantaneous water heater (7), wherein the instantaneous water heater (7) is arranged upstream of the flow inlet (5), wherein the fresh water station (1) comprises a connection (12) for a primary flow of the temperature control medium, characterized in that the instantaneous water heater (7) is arranged downstream of the connection (12) for a primary flow of the temperature control medium, wherein a branch (22) for the primary flow is arranged downstream of the connection (12) for the primary flow.wherein the branch (22) is located upstream of the instantaneous water heater (7), wherein the fresh water station (1) has a back wall, wherein the heat exchanger (2) and the instantaneous water heater (7) are attached directly or indirectly to the back wall.

Description

[0001] The invention relates to a fresh water station for providing hot drinking water (domestic hot water) to an apartment, wherein the fresh water station comprises a heat exchanger, the heat exchanger having a drinking water inlet and a drinking water outlet, the heat exchanger comprising a flow inlet and a return outlet for a temperature control medium, the fresh water station comprising an electric instantaneous water heater, the instantaneous water heater being arranged upstream of the flow inlet, and the fresh water station comprising a connection for a primary flow of the temperature control medium. The invention further relates to the use of the fresh water station in conjunction with a heat pump.

[0002] Such fresh water stations are well-established in practice and are increasingly being connected to heating systems with heat pumps. The heat pumps supply a primary flow temperature of a temperature-control medium, for example, 40°C, which is mixed to a secondary flow temperature of, for example, 30°C for underfloor heating. This mixing takes place in the fresh water station, where a return flow from the secondary circuit is mixed with the flow from the primary circuit in a mixing valve – according to the underfloor heating requirements. The water from the secondary circuit then leaves the fresh water station via a secondary flow connection, heading towards the underfloor heating system.

[0003] The water from the primary supply line, in accordance with established best practices, is also used in the heat exchanger to heat the domestic hot water. In the heat exchanger, the cold drinking water (cold water) is heated in a counterflow process by the warm temperature control medium from the primary circuit, with fluidic separation between these two circuits. However, the primary circuit's supply temperature of 40°C is insufficient to heat the drinking water to a target temperature of, for example, 50°C. For this reason, an instantaneous water heater is integrated on the drinking water side of the heat exchanger and downstream of the heat exchanger in the fresh water station. The approximately 50°C hot water then leaves the fresh water station via a hot water connection to a tap in the apartment. The tap will typically have a mixing valve for mixing with the cold water.

[0004] A disadvantage, however, is that the heat exchanger operates with a flow temperature of 40°C, which is often set by heat pumps and is also the optimal temperature for Legionella bacteria to multiply. If the drinking water remains in the heat exchanger for a while, it cools down only slowly. Thus, Legionella bacteria find ideal temperatures between 40°C and 25°C for a period of time.

[0005] A fresh water station mentioned at the beginning is also disclosed in EP 2 469 193 B1. According to variant 2 described therein, the instantaneous water heater is arranged in the flow line of the primary circuit and connected downstream of the boiler. Downstream of the instantaneous water heater and within the fresh water station, the flow line splits at a branch, so that a first branch leads into the counterflow heat exchanger. A second branch leads via a mixing valve (return of secondary circuit + flow of primary circuit) to a pump of the secondary flow. The secondary flow may, for example, supply underfloor heating. In this way, the additional heat supplied by the instantaneous water heater is used for both the secondary circuit / underfloor heating and for domestic hot water preparation. A disadvantage of the prior art according to EP 2 469 193 B1 is that the power consumption of such a system is relatively high and should therefore be reduced.The invention is therefore based on the objective of creating a particularly energy-efficient fresh water station.

[0006] This problem is solved by a fresh water station for providing hot drinking water, in particular for an apartment, wherein the fresh water station comprises a heat exchanger, wherein the heat exchanger has a drinking water inlet and a drinking water outlet, wherein the heat exchanger comprises a flow inlet and a return outlet for a temperature control medium, wherein the fresh water station comprises an electric instantaneous water heater, wherein the instantaneous water heater is arranged upstream of the flow inlet, and wherein the fresh water station comprises a connection for a primary flow of the temperature control medium. characterized by the fact that The instantaneous water heater is located downstream of the connection for a primary supply of the temperature control medium.

[0007] The invention is based on the initial finding that an electric instantaneous water heater has an efficiency of nearly 1, meaning that 1W of electrical power is converted into nearly 1W of heat output. The invention is further based on the finding that, depending on the heat pump type and under certain defined heat source conditions, heat pumps can typically provide between 2.5W (air source heat pump) and 5W (water source heat pump) of thermal output averaged over the year, using 1W of electrical power. The flow temperature supplied by heat pumps is relatively low – assuming energy-efficient operation – and may be around 35 to 40°C. Ideally, the heat pump feeds a secondary circuit that supplies surface heating elements such as underfloor, wall, and / or ceiling heating systems.

[0008] It was found that the instantaneous water heater should be positioned downstream of the primary supply connection for the heating medium so that it is used exclusively for domestic hot water production. Consequently, the instantaneous water heater is no longer used for the secondary circuit, which increases the efficiency of the overall system (domestic hot water production + heating system). This is because the heat pump generally operates significantly more efficiently than the instantaneous water heater and only approaches the efficiency of the instantaneous water heater at very low temperatures. Furthermore, the heat losses are lower due to the relatively short fluid path between the instantaneous water heater and the heat exchanger. As a result, the overall system becomes more efficient and energy-saving, thus solving the problem mentioned at the outset.Finally, the Legionella contamination of the drinking water is somewhat lower, as the instantaneous water heater is used less frequently and the fresh water station is therefore heated less on average over time.

[0009] The term "fresh water station" primarily refers to a component used for hot water preparation, which transfers heat from the temperature control medium to the drinking water via a heat exchanger. A fresh water station can be located centrally – particularly near a heat generator (e.g., a boiler or heat pump) – or decentrally within a building, for example, in an apartment.

[0010] The term "apartment station" preferably refers to a decentralized fresh water station and is preferably assigned to, and in particular only to, one apartment within a multi-family building, or installed within the apartment. In addition to hot water preparation, a fresh water station or apartment station can also supply the temperature control medium to one or more heating elements. Heating elements can be conventional radiators. A heating element can also be a surface heating element (e.g., underfloor heating).

[0011] The heat exchanger is preferably designed such that a portion of the heat from the temperature control medium is transferred to the drinking water flowing through it. Preferably, the heat exchanger is designed as a counterflow heat exchanger, so that the temperature control medium and the drinking water flow in opposite directions within the heat exchanger, at least in sections. The heat exchanger is advantageously elongated, so that it has a greater longitudinal extent in at least one direction than in the other two. The heat exchanger is expediently limited in its longitudinal extent by a first end and a second end.

[0012] Advantageously, the first end comprises half the longitudinal dimension of the heat exchanger. Conveniently, the second end of the heat exchanger comprises the other half of its longitudinal dimension. It is possible for the first end of the heat exchanger to comprise one-third of its longitudinal dimension. It is also possible for the second end of the heat exchanger to comprise one-third of its longitudinal dimension. It is advantageous for the first end to include the potable water inlet and the return outlet. It is preferred that the second end includes the potable water outlet and the supply inlet. The heat exchanger or the fresh water station is advantageously designed such that the potable water and the temperature control medium are fluidically separated from each other.

[0013] The term "temperature control medium" preferably refers to a flowable medium, which can be liquid and / or gaseous. The temperature control medium preferably comprises water and is particularly preferably free of limescale. It is possible that the temperature control medium contains an antibacterial additive.

[0014] The term "connection" can include a simple, open pipe. Preferably, the connection includes a device for simplifying the connection of a line to the connection. The connection can, for example, include a union nut which has, for instance, a 3 / 4-inch female thread. It is also possible that the connection includes a flared pipe end.

[0015] The term "primary circuit" preferably refers to a circuit of the temperature control medium, which begins at a heating system and leads back to the heating system via the domestic hot water station. It is preferred that the primary flow is located between the heating system and the heat exchanger or the heat exchanger's flow inlet. Advantageously, the primary return is located between the heat exchanger or the heat exchanger's return outlet and the heating system.

[0016] The term "secondary circuit" preferably refers to a circuit of the temperature control medium, which preferably begins in the fresh water station and leads back to the fresh water station via a secondary application – in particular a surface heating element. The secondary circuit expediently comprises a secondary supply and a secondary return. The secondary supply is preferably located between the fresh water station, or a branch for the secondary supply, or a pump, or a connection for the secondary supply, and the secondary application. The secondary return is expediently located between the secondary application and the fresh water station, or a branch for the secondary return, or a connection for the secondary return.

[0017] The term "branch" preferably refers to a fluid element having at least three fluidically interconnected openings. The branch can be configured as a T-piece or a Y-piece. It can also have four or more openings and be configured, for example, as a positive (+) piece. The branch may include at least one control element for controlling the flow conditions within the branch. A mixing valve is an example of a branch with a control element.

[0018] The flow directions within the various components of the fresh water station are preferably defined by the connections of the fresh water station or by one or more pumps within the house or apartment or the fresh water station itself. The fresh water station preferably comprises a potable water inlet, a hot water connection, a cold water connection, a primary return connection, a primary supply connection, a secondary supply connection, and / or a secondary return connection. The potable water inlet is expediently connectable to a suitable potable water line so that the potable water flows into the fresh water station via the potable water inlet connection. The hot water connection is preferably an outlet connection. Advantageously, the cold water connection is also an outlet connection. The primary supply connection is advantageously an inlet connection.The primary return connection is preferably an output connection. The secondary supply connection is preferably an output connection. The secondary return connection is preferably an input connection.

[0019] According to a particularly preferred embodiment, the instantaneous water heater is arranged directly upstream of the flow inlet, so that preferably no fluidic branch is located between the instantaneous water heater and the flow inlet. This ensures that a maximum of the electrically generated heat is fed into the heat exchanger, resulting in a particularly energy-efficient design. In particular, this prevents the heat from the instantaneous water heater from also being used for a secondary circuit. The secondary circuit should preferably be supplied with heat via relatively energy-efficient heat pumps. The term "directly upstream" preferably means that there is no fluidic branch (outlet and / or inlet) between the instantaneous water heater and the flow inlet.

[0020] It is highly preferred that a fluid path, for example a pipe with a connector at each end, connects the instantaneous water heater to the heat exchanger or the heat exchanger's inlet. It is particularly preferred that the fluid path is designed without branches, so that preferably the entire volume flow of the temperature control medium exiting the instantaneous water heater reaches the heat exchanger after passing only through the fluid path. The fluid path can comprise several pipes or fluid lines and several fluid components, as long as these do not include any branches. It is particularly preferred that the length of the fluid path is at most 300, 200, 100, 70, or 50 cm. This results in efficient operation and also tends to lead to a lower contamination with Legionella bacteria in drinking water.

[0021] Preferably, a branch for the primary supply is arranged downstream of the primary supply connection, with the branch preferably being located upstream of the supply inlet or the instantaneous water heater. Advantageously, the instantaneous water heater is arranged downstream of the branch. The branch for the primary supply advantageously serves to connect a secondary circuit to the fresh water station or to the primary circuit.

[0022] It is particularly preferred that a first branch of the primary supply line – especially via a pipe section – is connected to a branch for the secondary supply line, to a pump, or to a connection for the secondary supply line. This ensures that the supply line provided by the heating system or heat pump can be used, at least partially, for secondary purposes or for a surface heating element. Advantageously, the pipe section connects the primary circuit coming from a heating system – especially a centrally located one – to a secondary circuit, which is preferably located within an apartment, a household, or a section of a building. This allows for particularly efficient use of the thermal energy provided by the heat pump.

[0023] It is preferred that the fresh water station comprises the pipe section and / or the branch for the secondary supply and / or the pump and / or the connection for the secondary supply. Advantageously, the pipe section is arranged downstream of the branch for the primary supply or the connection for the primary supply. It is preferred that the branch for the primary supply is arranged between the connection for the primary supply and the pipe section. Advantageously, the pipe section is located between the branch for the secondary supply and the branch for the primary supply. It is preferred that the pump is arranged between the branch for the secondary supply and the connection for the secondary supply. The branch for the secondary supply preferably includes a control element and is particularly preferably designed as a mixing valve.Advantageously, the branch for the secondary supply is connected to the connection for the secondary return. It is highly preferred that the branch for the secondary supply is designed to mix a portion of the temperature control medium from the primary supply and a portion of the temperature control medium from the secondary return to provide the secondary supply.

[0024] According to a particularly preferred embodiment, the fresh water station has a sensor for the instantaneous water heater, wherein the sensor preferably detects the volume flow rate of a temperature control medium flowing through the instantaneous water heater. This allows the amount of heat required for the temperature control medium flowing through the instantaneous water heater to be determined, and in particular, determined via a proportional relationship. This ensures that the required amount of heat—and preferably only the required amount—is always available in the instantaneous water heater for the temperature control medium to be supplied, thus achieving a particularly efficient embodiment. It is preferred that the sensor for the instantaneous water heater includes a signal line. The signal line of the sensor for the instantaneous water heater can be connected directly to the instantaneous water heater or indirectly—for example, via a controller—to the instantaneous water heater.The sensor for the instantaneous water heater can be designed in such a way that the volume flow is determined only indirectly, for example via a flow velocity.

[0025] It is particularly advantageous that the fresh water station includes a valve for the primary return, wherein the primary return valve preferably controls a flow rate of the temperature control medium through the instantaneous water heater. It is especially preferred that the flow rate controlled by the primary return valve through the instantaneous water heater, or through the supply inlet, or through the return outlet, is presettable. This presettable setting can preferably be made by entering a digital value into a control unit or by adjusting a scale, for example, on a thermostat. The term "preset" preferably means that a readjustment can be made after the preset value has been entered. For example, a preset value can be made manually, and a sensor can then perform a readjustment or fine-tuning. It is advantageous that the primary return valve is located in the primary circuit.is located in the primary return line or in the fresh water station or downstream of the heat exchanger or upstream of the connection for the primary return line or upstream of the branch for the primary return line.

[0026] Preferably, the fresh water station includes a control unit. The control unit advantageously has a user interface or is connected to, or connectable to, a user interface – for example, in the form of an app. The control unit is preferably connected to, or connectable to, at least one sensor and / or at least one actuator. Preferably, the control unit is configured to control the at least one actuator or to regulate it taking into account the at least one sensor.

[0027] It is preferred that the branch for the primary return is connected to a branch for the secondary return or to a connection for the secondary return. Preferably, the branch for the secondary return is arranged between the connection for the secondary return and the branch for the primary return. Advantageously, the branch for the secondary return is located between the connection for the secondary return and the branch for the secondary supply.

[0028] It is preferred that the fresh water station has a temperature sensor for the hot water, the temperature sensor being preferably located at the potable water outlet or downstream of the potable water outlet. Advantageously, the temperature sensor has a signal line, which is preferably connected to, or connectable to, the control unit. Preferably, the control unit is connected to, or connectable to, the primary return valve. Advantageously, the primary return valve includes an actuator that can be controlled by the control unit. It is possible that the signal line is directly connected to, or connectable to, the primary return valve. It is highly preferred that the primary return valve adjusts the flow rate through the instantaneous water heater or through the return outlet of the heat exchanger depending on the temperature detected by the hot water temperature sensor.It is particularly preferred that the flow rate of the temperature control medium through the return outlet is adjusted accordingly, depending on whether the temperature of the hot water is detected by the temperature sensor. The hot water temperature sensor thus enables automatic readjustment of the flow rate of the temperature control medium through the instantaneous water heater, thereby automatically preventing both excessively low and excessively high hot water temperatures.

[0029] It is possible for the fresh water station to include a drinking water valve for controlling the drinking water flowing into the fresh water station and preferably into the heat exchanger, with the drinking water valve preferably being arranged upstream of the drinking water inlet. Providing the drinking water valve allows for the adjustment of a maximum flow rate of the drinking water flowing through the heat exchanger. The flow rate of the temperature control medium through the heat exchanger or through the instantaneous water heater is preferably, and in particular proportionally, dependent on the maximum flow rate of the drinking water.

[0030] It is possible that the drinking water valve and / or the primary return valve is / are designed such that the primary return valve is preferably at least preset by an adjustment of the drinking water valve. The drinking water valve and the primary return valve can be connected to each other by a coupling element, so that the primary return valve reacts automatically to an adjustment of the drinking water valve. Preferably, the coupling element is designed such that an adjustment of the maximum flow rate or the clear pipe cross-section of the drinking water valve results in a proportional change in the maximum flow rate or the clear pipe cross-section of the preset primary return valve.It is preferred that the drinking water valve and / or the coupling element and / or the primary return valve is / are designed such that a partial opening of the drinking water valve results in a partial opening of the primary return valve. Advantageously, the primary return valve is proportionally dependent on the drinking water valve.

[0031] It is preferred that the instantaneous water heater or the fresh water station is designed such that it allows a temperature difference of the heating medium of at most 30, 25, or 20 K, respectively. This means that the instantaneous water heater is particularly well-suited to its placement within the fresh water station. This is because the instantaneous water heater, as part of the primary supply, is supplied with a heating medium that, for example, has a temperature of 40 °C. In these cases, only a temperature difference of approximately 10 to 15 °C is required to provide a sufficiently high temperature of the heating medium in the heat exchanger. Preferably, the instantaneous water heater or the fresh water station is designed such that it allows a temperature difference of at least 5, 7, or 8 K for the heating medium.

[0032] Advantageously, the instantaneous water heater includes an inlet connection and / or an outlet connection. The inlet connection and / or the outlet connection preferably has a thread diameter of at least 3 / 4 or 1 inch.

[0033] Advantageously, the electrical rated power of the instantaneous water heater should be at least 1, 2, 4, 6, 8, or 10 kW. It is preferred that the rated power of the instantaneous water heater be limited to a maximum of 50, 40, 30, 25, 20, or 15 kW. It has been found that above 11 kW rated power, the approval process for the instantaneous water heater becomes significantly more complex.

[0034] Preferably, the instantaneous water heater includes connections for three phases of a three-phase current. It is highly preferred that the instantaneous water heater includes at least one thyristor or a thyristor circuit. It is highly preferred that the instantaneous water heater has at least 2, 3, 4, 7, 10, or 13 power levels (each with a power level greater than zero), wherein the power levels are preferably provided by the thyristor circuit. This enables precise control of the hot water temperature.

[0035] The term "power level" preferably includes continuously adjustable power levels and discretely adjustable power levels. According to a particularly preferred embodiment, the instantaneous water heater has more than 20, 30, or 40 power levels. It is particularly preferred that the instantaneous water heater is operated in a controlled manner. Advantageously, the fresh water station is designed such that the power level of the instantaneous water heater is selected depending on the temperature sensor and / or the temperature probe and / or the sensor for the instantaneous water heater.

[0036] According to a highly preferred embodiment, the instantaneous water heater comprises a cavity. The cavity is advantageously arranged in the flow direction between the inlet and outlet connections. Preferably, the instantaneous water heater comprises at least one electric heating element and, more preferably, three electric heating elements. The at least one electric heating element is advantageously designed as a heating rod, in particular as a coiled or spiral heating rod. The at least one electric heating element preferably projects into the cavity. It is particularly preferred that the instantaneous water heater is designed such that the temperature-control medium – especially in the cavity of the instantaneous water heater – comes into contact with, or flows around, the at least one electric heating element.In contrast to indirectly heating electric instantaneous water heaters (no direct contact of the temperature control medium with the electric heating element), this allows for a particularly fast response and a compact design of the instantaneous water heater.

[0037] It is advantageous for the fresh water station to include a differential pressure regulator, a pump, an expansion element and / or a dirt trap.

[0038] The fresh water station advantageously features a shut-off valve for the secondary return. This shut-off valve is preferably located between the branch for the primary return and the connection for the secondary return, or between the branch for the secondary return and the secondary return itself. The shut-off valve for the secondary return can be operated manually or electronically.

[0039] It is preferred that the fresh water station has a temperature sensor for detecting the temperature of the temperature control medium in the fluid path between the instantaneous water heater and the heat exchanger. It is advantageous if the temperature sensor has a signal line. The signal line of the temperature sensor is preferably connected to the control unit. Advantageously, the instantaneous water heater is also connected to the control unit so that the instantaneous water heater can be adjusted – preferably depending on the temperatures detected by the temperature sensor.

[0040] It is preferred that the fresh water station has a housing that at least partially, and preferably completely, encloses the heat exchanger and the instantaneous water heater. It is possible that the housing at least partially, and preferably completely, encloses the pump, the sensor, the valve, the shut-off valve, the secondary supply branch, the primary supply branch, the differential pressure regulator, the secondary return branch, the potable water inlet branch, the expansion element, the strainer, the hot water connection, the potable water inlet connection, the cold water connection, the primary return connection, the primary supply connection, the secondary supply connection, and / or the secondary return connection.This allows, in particular, a large concentration of the fluidic components on the fresh water station, which greatly simplifies the installation work in individual households and reduces costs accordingly.

[0041] According to a preferred embodiment, the fresh water station comprises a rear panel. Preferably, the rear panel, or a rear side of the rear panel, is designed for mounting on a vertical surface, particularly a wall. It is highly preferred that the heat exchanger and / or the instantaneous water heater is / are attached indirectly or directly (in direct contact) to the rear panel or to a front side of the rear panel.It is possible that the pump, sensor, valve, shut-off valve, secondary supply branch, primary supply branch, differential pressure regulator, secondary return branch, potable water inlet branch, expansion element, strainer, hot water connection, potable water inlet connection, cold water connection, primary return connection, primary supply connection, secondary supply connection, and / or secondary return connection are attached directly or indirectly (in direct contact) to the rear panel or a front panel. This allows for a high concentration of fluidic components at the fresh water station, which greatly simplifies installation work in individual households and reduces costs accordingly.

[0042] The aforementioned problem is solved by using a fresh water station according to the invention in a fluidic connection with a primary circuit and / or with a low-temperature supply, preferably with a low-temperature supply of a primary circuit, wherein the primary circuit or the low-temperature supply is preferably provided by a low-temperature heat generator, for example, a heat pump and / or a solar thermal system. It is possible that a non-low-temperature primary circuit provides a low-temperature supply or a non-primary circuit for the fresh water station, e.g., by means of a heat exchanger or fluid mixer – for example, in the form of a storage tank. The term "fluidic connection" preferably includes indirect and / or direct fluidic connections, such that at least one other fluid element (e.g., a heat pump, a heat exchanger, or a storage tank) is present between the fresh water station and the heat generator.a heat exchanger and / or a fluid mixer) may be connected.

[0043] Preferably, the fresh water station, heat exchanger, flow inlet, or instantaneous water heater of the fresh water station is in fluidic connection with a heat generator, and in particular a low-temperature heat generator. The term "low-temperature heat generator" preferably refers to a heat generator whose flow temperature is below 50°C, 45°C, or 40°C. This allows for efficient supply of a surface heating element. The term "heat generator" preferably includes conventional heating systems, and in particular heating systems with a flow temperature of at least 51°C or 55°C.

[0044] Preferably, the fresh water station is an apartment station. It is highly preferred that the fresh water station or apartment station is fluidically connected to a secondary circuit and, in particular, to a surface heating element.

[0045] Preferably, the low-temperature heat generator is at least indirectly connected to the domestic hot water station or a connection for the primary flow and / or a connection for the primary return. It is preferred that the domestic hot water station or the connection for the secondary flow or the connection for the secondary return is connected to a secondary utilization, in particular to a surface heating element. This allows for particularly efficient use of the domestic hot water station and the amount of heat supplied.

[0046] An embodiment of the invention is illustrated below with reference to a figure. It shows Fig. 1 a hydraulic circuit diagram of a fresh water station according to the invention.

[0047] The circuit diagram of an exemplary embodiment of a fresh water station 1 according to the invention is in the only Fig. Figure 1 shows the domestic hot water station 1. In this embodiment, the domestic hot water station 1 may be connected to a heat pump (not shown). The heat pump can provide a primary supply, which may have a supply temperature of, for example, 40 °C. A primary return flow is advantageously routed from the domestic hot water station 1 back to the heat pump. The primary supply and the primary return, like the heat pump itself, are components of a primary circuit. The valves in this embodiment are not electronically controlled, but rather statically controlled or regulated by thermostats. According to an advantageous electronic variant (not shown here), signal lines from the temperature sensors are routed to a control unit, which then controls the valves.

[0048] Fresh water station 1 can be connected to a surface heating element, such as underfloor, ceiling, and / or wall heating. The surface heating element (not shown) is advantageously supplied via a secondary flow, which can have a flow temperature of, for example, 30 °C. A secondary return flow from the surface heating element back to fresh water station 1 is also advantageous. The secondary flow and the secondary return, like the surface heating element itself, are components of a secondary circuit.

[0049] The fresh water station 1 is expediently assigned to one apartment, and preferably only one apartment or household, whereas the heat pump is expediently assigned to several apartments or households. In contrast, a secondary circuit comprising the secondary flow and the secondary return can again be assigned to one apartment, and preferably only one, and in particular to the same apartment as the fresh water station 1.

[0050] The fresh water station 1 of this embodiment expediently comprises a connection 11 for the primary return, a connection 12 for the primary supply, a connection 13 for the secondary supply, and / or a connection 14 for the secondary return. Connections 11 and 12 are expediently connected to the heat pump. Connections 13 and 14 are advantageously connected to the surface heating element.

[0051] It is preferred that the fresh water station 1 includes a drinking water inlet connection 9. The temperature of the drinking water at the drinking water inlet connection may be approximately 10 °C to 12 °C. Advantageously, the fresh water station 1 includes a cold water connection 10 for supplying cold drinking water to the dwelling. Preferably, the fresh water station 1 includes a hot water connection 8 for supplying hot drinking water to the dwelling. The hot water connection 8 and the cold water connection 10 can be connected to a plurality of mixing valves in the dwelling or household, in particular to mixing valves in a bathroom and in a kitchen.

[0052] The fresh water station 1 of this embodiment comprises a heat exchanger 2 and an electric instantaneous water heater 7. The heat exchanger 2 includes a potable water inlet 3, a potable water outlet 4, a flow inlet 5, and a return outlet 6. It is preferred that the heat exchanger 2 allows the potable water to flow in the opposite direction to the heating water or temperature control medium. Advantageously, the heat exchanger 2 is designed as a counterflow heat exchanger. The potable water and the temperature control medium are expediently separated from each other fluidically within the heat exchanger 2, the fresh water station 1, and the heat exchanger 2, respectively.

[0053] It is preferred that the potable water inlet 9 is connected to the potable water supply 3 of the heat exchanger 2. Preferably, a branch 30 for the potable water inlet is located between the potable water inlet 9 and the potable water supply 3 of the heat exchanger 2. Advantageously, a first branch of the branch 30 for the potable water inlet is connected to the potable water supply 3 of the heat exchanger 2. It is preferred that a second branch of the branch 30 for the potable water inlet is connected to the cold water connection 10. It is preferred that the branch 30 for the potable water inlet does not have an actuating element.

[0054] It is preferred that the hot water connection 8 is connected to the potable water outlet 4 of the heat exchanger 2. Preferably, the potable water inlet 3 and the return outlet 6 of the heat exchanger are arranged at a first end of the heat exchanger 2. Advantageously, the potable water outlet 4 and the flow inlet 5 of the heat exchanger 2 are located at a second end of the heat exchanger 2.

[0055] The electric flow heater 7 is arranged upstream of the supply inlet 5 of the heat exchanger 2. Advantageously, the electric flow heater 7 and the heat exchanger 2 are connected to each other by a fluid path 25. It is preferred that the fluid path 25 is branch-free and, in particular, free of other components. Advantageously, the electric flow heater 7 and the heat exchanger 2 are connected to each other only via the fluid path 25. It is preferred that no branch and / or no other fluid component, with the exception of the fluid path 25, is / are arranged between the electric flow heater 7 and the heat exchanger 2. The term "branch" preferably excludes dead legs and means, in particular, that all branches are at least temporarily flowed through. The fluid path 25 preferably comprises a pipe, and in particular only a pipe with two axial connections. The fluid path 25, orThe pipe of the fluid section 25 advantageously has a length of less than 200 or 100 or 80 or 60 or 50 cm.

[0056] Advantageously, the flow heater 7 is arranged between the heat exchanger 2 or the fluid section 25 and the connection 12 for the primary supply. A branch 22 for the primary supply is advantageously located between the flow heater 7 and the connection 12 for the primary supply. Preferably, a first branch of the branch 22 for the primary supply is connected to the flow heater 7. It is advantageous that a second branch of the branch 22 for the primary supply is connected to the connection 13 for the secondary supply. The fresh water station 1 may include a dirt trap 27 for filtering dirt from the temperature control medium. The dirt trap 27 is preferably arranged between the connection 12 for the primary supply and the branch 22 for the primary supply.

[0057] Preferably, the fresh water station 1 comprises a fluid line 26. The fluid line 26 is preferably connected to an inlet of the instantaneous water heater 7. Advantageously, the fresh water station 1 includes a sensor 19 for the instantaneous water heater 7. The sensor 19 is preferably arranged between the branch 22 for the primary supply and the instantaneous water heater 7, or on the fluid line 26. Advantageously, the fluid line 26 is designed without any branches. It is preferred that there is no branch between the sensor 19 or the branch 22 and the instantaneous water heater 7.

[0058] The sensor 19 for the instantaneous water heater 7 preferably determines a volume flow rate of the temperature control medium in the fluid line 26 and transmits data on the volume flow rate via a - in Fig. 1. The signal line to the flow heater 7 is shown in dashed lines. Preferably, the flow heater 7 heats the temperature control medium depending on the data for the volume flow rate. Advantageously, the flow heater 7 heats the temperature control medium linearly – in particular proportionally – to the volume flow rate in the fluid line 26.

[0059] It is preferred that a branch 29 for the secondary return is connected downstream of the connection 14 for the secondary return in the flow direction. A first branch of the branch 29 for the secondary return preferably connects the connection 14 for the secondary return to the connection 13 for the secondary supply. A second branch of the branch 29 for the secondary return preferably connects the connection 14 for the secondary return to the connection 11 for the primary supply.

[0060] Advantageously, the fresh water station 1 – or a section of the secondary circuit within the fresh water station 1 – includes a branch 23 for the secondary supply, which preferably includes a control element and is further preferably designed as a mixing valve. The control element may be designed as a thermostat and expediently allows a fixed setpoint temperature of the secondary supply.

[0061] The branch 23 for the secondary supply advantageously comprises three connections and is preferably connected to the second branch of branch 22, the first branch of branch 29 for the secondary return, and / or to connection 13 for the secondary supply. Advantageously, the connection of branch 23 for the secondary supply that is connected to connection 13 for the secondary return forms an outlet of branch 23 for the secondary supply. The fresh water station advantageously has a pipe section that is preferably arranged between branch 22 for the primary supply and branch 23 for the secondary supply.

[0062] It is advantageous that the fresh water station 1 includes a pump 24. The pump 24 is preferably arranged between the connection 13 for the secondary supply and the branch 23 for the secondary supply. The pump 24 expediently drives the secondary supply.

[0063] It is preferred that the fresh water station includes a branch 18 for the primary return. The branch 18 is advantageously located between the return outlet 6 of the heat exchanger 2 and the connection 11 for the primary return. It is preferred that the connection 14 for the secondary return, or the second branch of the branch 29, is connected to the branch 18 for the primary return. Preferably, the branch 18 is connected to the connection 11 for the primary return.

[0064] Advantageously, a shut-off valve 17 is arranged between the branch 18 for the primary return and the branch 29 for the secondary return, preferably to prevent the heating of the temperature control medium from the secondary return when necessary. The shut-off valve 17 therefore serves to give priority to hot water preparation over the secondary circuit.

[0065] Preferably, the fresh water station 1 includes a temperature sensor 31 for detecting the temperature of the temperature control medium exiting the heat exchanger 2 or the return outlet 6 of the heat exchanger 2. The temperature sensor 31 is preferably arranged between the return outlet 6 and the branch 18. Particularly preferably, a - in Fig. 1. The signal line shown in dashed lines connects the temperature sensor 31 to the shut-off valve 17, so that the shut-off valve 17 is advantageously controlled by the temperature sensor 31.

[0066] The fresh water station 1 advantageously includes a valve 16 for the primary return to control the flow rate of the temperature control medium through the heat exchanger 2. It is preferred that the valve 16 for the primary return is arranged downstream of the return outlet 6 of the heat exchanger 2. Advantageously, the valve 16 is arranged between the branch 18 for the primary return and the return outlet 6.

[0067] Advantageously, the fresh water station 1 has a temperature sensor 34 for measuring the temperature at the drinking water outlet 4 of the heat exchanger 2. The temperature sensor is preferably connected via a - in the Fig. The signal line (shown with a dashed line) is connected to valve 16 for the primary return. This allows the valve 16 to counteract excessively high or low temperatures of the heated drinking water. For example, if the heated drinking water at the drinking water outlet 4 is still somewhat too cool, valve 16 can increase the flow rate of the temperature control medium through the heat exchanger 2 to achieve a setpoint of, for example, 50°C.

[0068] Advantageously, the fresh water station 1 has an adjustment element 35 for a hot water setpoint. The adjustment element 35 may be designed as a thermostat and may have a temperature scale. The adjustment element 35 is preferably designed to control a flow rate – expediently next to the temperature sensor 35 – through the valve 16 for the primary return.

[0069] Preferably, the fresh water station 1 comprises a drinking water valve 32 for preferably controlling a volume flow of drinking water through the heat exchanger 2. The drinking water valve 32 is advantageously arranged between the drinking water inlet 3 of the heat exchanger 2 on the one hand and the drinking water connection 10 or the drinking water inlet 9 or the branch 30 on the other hand.

[0070] Particularly preferably, the adjusting element 35 is connected to the drinking water valve 32 such that the adjusting element 35 controls a flow rate through the drinking water valve 32. It is especially preferred that the adjusting element 35 is connected to a coupling element 33. The coupling element 33 is preferably designed or arranged such that it simultaneously controls the valve 16 for the primary return and the drinking water valve 32, and in particular controls both flow rates linearly and preferably proportionally to each other. This ensures that the flow rates of the temperature control medium and the drinking water in the heat exchanger 2 are always coordinated. If necessary, the flow rate in the valve 16 can be readjusted via the temperature sensor 34 without simultaneously changing the flow rate in the drinking water valve 32.

[0071] Advantageously, the fresh water station 1 comprises a differential pressure regulator 20, 21. The differential pressure regulator 20, 21 preferably includes a differential pressure valve 20 and, more preferably, a signal transmitter 21. The differential pressure valve 20 is advantageously located between the branch 18 for the primary return and the connection 11 for the primary return. Preferably, the signal transmitter 21 is connected to the primary supply and, in particular, to the connection 12 for the primary supply. It is possible that the strainer 27 is arranged between the signal transmitter 21 and the connection 12 for the primary supply. The signal transmitter 21 is preferably connected to the differential pressure valve 20 via a pulse line (shown with dashed lines).

[0072] Advantageously, the fresh water station 1 includes an expansion element 28. The expansion element 28 is preferably connected to the drinking water inlet connection 9 and / or to the branch 30 for the drinking water inlet and / or to the drinking water supply 3 of the heat exchanger 2. It is highly preferred that the fresh water station 1 comprises a housing 15. It is highly preferred that the housing 15 at least partially and preferably completely encloses the heat exchanger 2, the instantaneous water heater 7, and preferably at least one further component or components. Reference symbol list: 1 Fresh water station 2 heat exchangers 3 Drinking water supply from 2 4 Drinking water outlet from 2 5 preliminary input from 2 6 Return outlet from 2 7 instantaneous water heaters 8 Hot water connection 9 Drinking water inlet connection 10 Cold water connection 11 Connection for primary return 12 Connection for primary supply 13 Connection for secondary supply 14 Connection for secondary return 15 cases 16 Primary return valve 17 Shut-off valve for the secondary return 18 Branch for the primary return 19 Sensor for the instantaneous water heater 20 Differential pressure valve 21 signal transmitters for 20 20,21 Differential pressure regulator 22 Branch for the primary supply 23 Branch for the secondary supply 24 pump 25 Fluid section 26 Fluid line 27 mud flaps 28 Expansion element 29 Branch for the secondary return 30 Branch for the drinking water inlet 31 temperature sensor for 6 32 Drinking water valve 33 Coupling element of 16, 32, 35 34 temperature sensors 35 Setting element for the hot water setpoint QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] EP 2 469 193 B1

[0005]

Claims

Fresh water station (1) for providing hot drinking water, in particular for an apartment, wherein the fresh water station (1) comprises a heat exchanger (2), wherein the heat exchanger (2) has a drinking water inlet (3) and a drinking water outlet (4), wherein the heat exchanger (2) comprises a flow inlet (5) and a return outlet (6) for a temperature control medium, wherein the fresh water station (1) comprises an electric instantaneous water heater (7), wherein the instantaneous water heater (7) is arranged upstream of the flow inlet (5), wherein the fresh water station (1) comprises a connection (12) for a primary flow of the temperature control medium, characterized in that the instantaneous water heater (7) is arranged downstream of the connection (12) for a primary flow of the temperature control medium. Fresh water station (1) according to claim 1, wherein the instantaneous water heater (7) is arranged directly upstream of the supply inlet (5), so that preferably there is no fluidic branch between the instantaneous water heater (7) and the supply inlet (5). Fresh water station (1) according to claim 1 or 2, wherein a branch (22) for the primary supply is arranged downstream of the connection (12) for the primary supply, wherein the branch (22) is preferably located upstream of the supply inlet (5) or the instantaneous water heater (7). Fresh water station (1) according to one of claims 1 to 3, wherein the fresh water station (1) has a sensor (19) for the instantaneous water heater (7), wherein the sensor (19) preferably detects a volume flow of a temperature control medium flowing through the instantaneous water heater (7). Fresh water station (1) according to one of claims 1 to 4, wherein the fresh water station (1) comprises a valve (16) for a primary return, wherein the valve (16) for the primary return preferably controls a volume flow of the temperature control medium through the instantaneous water heater (7). Fresh water station (1) according to one of claims 1 to 5, wherein the fresh water station (1) has a temperature sensor (34) for the hot water, wherein the temperature sensor (34) is preferably arranged at the drinking water outlet (4) or downstream of the drinking water outlet (4). Fresh water station (1) according to one of claims 1 to 6, wherein the instantaneous water heater (7) or the fresh water station (1) is designed such that the instantaneous water heater (7) allows a temperature rise of the temperature control medium of at most 30 or 25 or 20K. Fresh water station (1) according to one of claims 1 to 7, wherein the electrical rated power of the instantaneous water heater (7) amounts to at least 4 or 6 or 8 or 10 kW. Fresh water station (1) according to one of claims 1 to 8, wherein the instantaneous water heater (7) comprises connections for three phases of a three-phase current, wherein it is preferred that the instantaneous water heater (7) has at least one thyristor or a thyristor circuit. Fresh water station (1) according to one of claims 1 to 9, wherein the instantaneous water heater (7) has at least 2 or 3 or 4 or 7 or 10 or 13 power levels. Fresh water station (1) according to one of claims 1 to 10, wherein the instantaneous water heater (7) comprises at least one electric heating element and further preferably three electric heating elements, wherein the instantaneous water heater (7) is preferably designed such that the temperature control medium comes into contact with the at least one electric heating element or flows around the at least one electric heating element. Fresh water station (1) according to one of claims 1 to 11, wherein the fresh water station (1) has a rear wall, wherein it is preferred that the heat exchanger (2) and / or the instantaneous water heater (7) is / are attached directly or indirectly to the rear wall or to a front side of the rear wall. Fresh water station (1) according to one of claims 1 to 12, wherein the fresh water station (1) comprises a connection (13) for a secondary supply of the temperature control medium and / or a connection (14) for a secondary return of the temperature control medium. Fresh water station (1) according to one of claims 1 to 13, wherein the fresh water station (1) comprises three drinking water connections (8, 9, 10), preferably a drinking water inlet connection (9), a hot water connection (8) and / or a cold water connection (10). Use of a fresh water station (1) according to one of claims 1 to 14 in fluidic connection with a primary circuit and / or with a low-temperature supply, preferably with a low-temperature supply of a primary circuit, wherein the primary circuit or the low-temperature supply is preferably provided by a low-temperature heat generator, for example by a heat pump, wherein the fresh water station (1) or apartment station is preferably fluidically connected to a secondary circuit and in particular to a surface heating element.

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