Decentralised water supply station

Abstract

Decentralized water supply station for heating and providing drinking water, comprising a heat exchanger connected on the primary side to a flow and return of the heating water, a drinking water connection for connecting the secondary side of the heat exchanger to a drinking water supply line, and a hot water outlet for the heated drinking water arranged on the secondary side of the heat exchanger, wherein the decentralized water supply station includes a pressurized hot water storage tank or a steam storage tank, on which a hot water or steam outlet is arranged, which is connected to the hot water outlet arranged on the secondary side of the heat exchanger, and the heated drinking water from the heat exchanger is mixed with the hot water or steam and supplied to the consumers via a hot water line.

Description

[0001] The invention relates to a decentralized water supply station and a method for heating and providing drinking water comprising a heat exchanger connected on the primary side to a flow and return of the heating water for supplying the heat energy, a drinking water connection for connecting the secondary side of the heat exchanger to a drinking water supply line and a hot water outlet arranged on the heat exchanger for the heated drinking water.

[0002] The hot drinking water in a building typically has a temperature between 40 and over 60°C, depending on whether or not a circulation system is present. With a circulation system, the hot drinking water must be heated to over 60°C. If there is no circulation system, which is only possible with a pipe volume of less than three liters between the water source and the consumer and requires decentralized water treatment, the hot drinking water will be between 40 and 50°C. To reach this temperature, cold drinking water drawn from the public water supply is heated to the desired temperature. For this purpose, a decentralized water supply station is usually installed in apartments or for each user unit. This station is connected to the building's plumbing system as well as to public connections such as the drinking water supply.There are already various ways to heat cold drinking water to a standard hot water temperature supplied to the consumer.

[0003] EP 2 369 243 A2 discloses a method for heating drinking water, wherein the drinking water is preheated by means of a heat exchanger and then brought to the desired hot water temperature by means of an electric reheater, wherein both the heat exchanger and the electric reheater are installed in a residential unit and can therefore be individually controlled by each user unit. A disadvantage of this method is the high energy cost for reheating the hot water due to the electric reheater.

[0004] The 10 2005 007 673 A1 discloses a hot water preparation system in which a heat exchanger also preheats the cold drinking water and then brings it to the consumer temperature by means of an instantaneous water heater.

[0005] A disadvantage of the current state of the art is the high energy costs due to the electric auxiliary heaters. Similarly, when auxiliary heaters are omitted, the temperature of the flow line for the heat energy supply to the heat exchanger must be considerably higher to achieve the desired final temperature of the hot drinking water. This results in an undesirably higher heat transfer in the supply lines to the heat exchanger, again leading to very high energy costs.

[0006] The object of the invention is to propose a decentralized water supply station and an associated method that enables cost-efficient heating of drinking water as well as individual control of the hot water temperature at the consumer per usage unit.

[0007] This problem is solved according to the invention by the decentralized water supply station comprising a pressurized hot water storage tank or a steam storage tank, on which a hot water or steam outlet is arranged, which is connected to the hot water outlet arranged on the secondary side of the heat exchanger, and the heated drinking water from the heat exchanger is mixed with the hot water or steam and supplied to the consumers via a hot water pipe.

[0008] The decentralized water supply station according to the invention for heating and providing drinking water includes a heat exchanger connected on the primary side to a flow and return line of the heating water. The heating water supplied to the heat exchanger can originate from a building installation or a central building heating system, such as a central heat pump in a building, or from a district heating network. Furthermore, the decentralized water supply station according to the invention includes a drinking water connection for connecting the secondary side of the heat exchanger to a drinking water supply line, which connects to the public drinking water supply network. A hot water outlet for the heated drinking water is arranged on the secondary side of the heat exchanger. The decentralized water supply station according to the invention also has a pressurized hot water storage tank or a steam storage tank.The pressurized hot water storage tank has the advantage that the water it contains has a temperature of over 100°C and yet remains liquid. Due to this high temperature, only a small amount of the water above 100°C is needed to mix with the heated water from the heat exchanger to achieve the desired hot water temperature for the consumer. The hot water from the storage tank preferably has a temperature of 101–110°C.

[0009] Similarly, in a steam storage tank, only a small volume of hot steam is required to bring the heated water from the heat exchanger to the desired final temperature of the hot drinking water supplied to the consumer. Each hot water storage tank or steam storage tank has an outlet connected to the hot water outlet on the secondary side of the heat exchanger. This allows the heated drinking water from the heat exchanger to be mixed with the hot drinking water from the hot water storage tank or the steam from the steam storage tank, and then supplied to the consumer via a hot water pipe. The hot water pipe connects to the combined outlet pipes and extends within the unit or apartment wherever a hot water connection is required.

[0010] Both the hot water storage tank and the steam storage tank have a drinking water connection, which preferably connects directly to a drinking water supply line. Of course, it is also possible to branch off the drinking water connection for both the hot water storage tank and the steam storage tank from the decentralized water supply station.

[0011] On the primary side, as already mentioned, the heat exchanger is connected to the flow and return of the heating water to transfer the required heat energy to the cold drinking water fed in on the secondary side. Of course, in addition to the primary heating water circuit flowing through the heat exchanger, the primary side can also have other heating water circuits, which are used, for example, for space heating.

[0012] It has proven advantageous to install a valve between the hot water outlet of the pressurized hot water storage tank and the hot water outlet of the heat exchanger. This allows the mixing rate to be regulated so that the hot drinking water supplied to the consumer preferably has a temperature between 40 and 50°C. Preferably, the flow rate of the heated drinking water from the heat exchanger, as well as the flow rate from the hot water storage tank, can be individually adjusted or regulated.

[0013] It has proven advantageous if the valve is designed as a thermostatic mixing valve. This allows the valve to be preset to a desired temperature, so that if this temperature is exceeded, the incoming hot water flow decreases due to the narrowing of the flow towards the hot water outlet and / or the flow rate to the heated drinking water from the heat exchanger increases. This depends on the setting of the mixing valve. Preferably, a 3-way mixing valve is used for this purpose. Alternatively, a control valve can be used that has an electrically controlled actuator connected to a controller and monitors the water temperature with a temperature sensor, so that the control valve regulates the flow rate in the outlet lines accordingly.Naturally, the control system can regulate the valve based on the hot water temperature at the consumers or in the hot water pipe, as well as detect the temperature of the heated drinking water from the heat exchanger and the hot water temperature, and regulate the flow rate based on these temperatures.

[0014] It has proven advantageous to install a steam-water mixer between the steam outlet of the steam storage tank and the hot water outlet of the heat exchanger. Such a mixer allows the hot steam from the steam storage tank to mix with the heated drinking water exiting the heat exchanger, in order to achieve the desired hot water temperature supplied to the consumer.

[0015] Preferably, the heat exchanger used in the decentralized water supply station is a water-to-water heat exchanger. This water-to-water heat exchanger creates a hydraulic division into a primary side, through which the heating water flows, thereby transferring thermal energy into the heat exchanger, and a secondary side, which is connected to the potable water supply and through which the potable water flows, absorbing the thermal energy of the transferred heat, thus heating the potable water. The potable water is heated according to the temperature of the supply line on the primary side. Due to the addition of hot water or steam, the supply temperature can be reduced, which on the one hand leads to cost reductions and on the other hand also results in less heat transfer to the cold water line supplying the decentralized water station.

[0016] It has proven advantageous that the pressurized hot water storage tank and the steam storage tank can be electrically heated. This allows for rapid and efficient water heating. Preferably, a control system is in place that activates the electrical heating according to the temperature drop in the storage tank and stops it when the desired temperature is reached. It is advantageous if the control system is linked to the time and, if necessary, a calendar, so that sufficient hot water or steam is available in the storage tank in the morning, or that the storage tank is not reheated to its maximum temperature overnight, but rather this can be done shortly before morning to minimize the time until use.

[0017] It has proven advantageous to have a safety valve in the hot water line to completely open or close it. The valve is preferably a motorized or solenoid valve and allows the flow to be completely stopped. This ensures safety by detecting early on if excessively hot water flows through the hot water line, allowing the valve to close automatically.

[0018] Preferably, a temperature sensor is arranged on the hot water pipe for safety monitoring of the hot water temperature. Based on the water temperature detected by the temperature sensor in the hot water pipe, the safety valve closes if a predetermined maximum water temperature is exceeded, thus ensuring that excessively hot water does not reach the consumer and protecting them from scalding. Preferably, the safety valve opens automatically after a certain time, based on empirical data on how long it takes for the water to cool down, or when the temperature sensor detects that the temperature is below the maximum temperature. It is advantageous if, based on the temperature sensor detecting that the maximum temperature has been exceeded, the mixing valve or...The steam-water mixer will automatically readjust itself, or a message will be sent indicating that readjustment is necessary so that the hot water reaches the consumer at the desired temperature.

[0019] The inventive method for heating and supplying hot drinking water with a decentralized water supply station includes preheating the drinking water in the secondary side of a heat exchanger. The heat energy is supplied to the heat exchanger via a heat exchanger connected on the primary side to a flow and return of the heating water. Hot water or steam is mixed with the drinking water heated by the heat exchanger downstream of the heat exchanger. The hot water is heated in a pressurized hot water storage tank located in the decentralized water supply station and fed to the heated drinking water exiting the heat exchanger via an outlet or outlet line. The heated water and water are then mixed together and supplied to the consumers in the unit via an outlet hot water line.Alternatively, the heated drinking water from the heat exchanger can also be mixed with steam located in the steam storage tank in the decentralized water supply station to achieve the desired temperature level.

[0020] It is advantageous if the added hot water from the hot water storage tank has a temperature > 100°C. For the water to remain liquid at this temperature, the hot water storage tank must be pressurized; preferably, the pressure of a hot water storage tank is between 2 and 8 bar.

[0021] It has proven advantageous if the hot water has a temperature between 101 and 110 °C.

[0022] Preferably, the hot water is mixed with the heated drinking water in the heat exchanger via a valve, preferably a thermostatic mixing valve or a control valve, thereby regulating the temperature of the hot drinking water for the consumer by controlling the flow rate. Alternatively, the flow rate of the hot water and the heated water in the valve is regulated based on the existing temperature of the hot water. As already mentioned, the regulation can also be based on the existing temperatures of the hot water and the heated water.

[0023] It has proven advantageous to mix steam into the heated drinking water via a steam-water mixer. Depending on the existing temperatures and the desired temperature of the hot drinking water for the consumer, the amount of steam added to the heated drinking water is adjusted accordingly.

[0024] All design options can be freely combined with each other, and to avoid repetition, the features of the device automatically refer to the process and vice versa.

[0025] An embodiment of the invention is described with reference to the figure, although the invention is not limited to this embodiment. It shows: Fig. 1 a schematic representation of a decentralized water supply station according to the invention.

[0026] Figure 1 Figure 1 shows a schematic representation of a variant of a decentralized water supply station 1 according to the invention, with a hot water storage tank 5 or steam storage tank 5. The water supply station 1 according to Figure 1The system preferably comprises a water-to-water heat exchanger 2. The heat exchanger is, for example, designed as a plate heat exchanger. The heat exchanger 2 has a primary side I and a secondary side II, the two sides being hydraulically separate. The primary side I of the heat exchanger 2 is supplied with the primary heating water circuit. This means that the primary supply of the heating water HZ-VL-PR flows into the primary side I of the heat exchanger 2, thereby transferring the thermal energy into the heat exchanger 2. The heating water is returned to the heating system, be it a central heating system in the building or a district heating system, via the return line HZ-RL-PR. The transferred thermal energy is then transferred to the potable water flowing through the secondary side II, which is then heated.

[0027] Preferably, a primary heating flow I (HZ-VL-PR) is arranged, which, as already described, supplies the heat energy to the heat exchanger 2, and the primary heating return I (HZ-RK-PR) returns the heating water, from which the heat energy was extracted in the heat exchanger 2, back to the heating system. In addition, a secondary heating flow I (HZ-VL-SK) can also be present, branching off from the primary heating flow and, for example, heating a radiator in a room. Similarly, the heating return can also have a secondary line (HZ-RK-SEK) that can also be used as a heat or energy source where a lower temperature level is required. For example, this can be used to heat underfloor heating or an anteroom before the return flow returns to the heating system.Of course, countless other designs for using the heating water on the primary side of the heat exchanger 2 are possible, which are already known from the state of the art.

[0028] The secondary side II of the heat exchanger includes a potable water connection 4 which is connected to the potable water supply line TW. This preferably connects to the public potable water network (not shown). The cold potable water to be heated is supplied to the heat exchanger 2 via the potable water connection 4. Hydraulically separate from the primary side of the heat exchanger 2, the heat energy 2, which is supplied via the heating water flow line HZ-VL-PR, is absorbed and exits the heat exchanger 2 heated via the hot water outlet 4 on the heat exchanger. The heated water exiting the heat exchanger does not yet have the desired temperature of hot potable water for the consumer.

[0029] To reach the desired temperature level, a pressurized hot water storage tank or steam storage tank 5 is installed in the decentralized water supply station. In the hot water storage tank, the heated drinking water is heated to a temperature above 100 °C. Since the hot water storage tank operates at a pressure between 2 and 8 bar, the water remains liquid even above 100 °C. This high temperature means that only a small amount of the hot water needs to be added to the heated water coming from heat exchanger 2 to reach the desired temperature level of approximately 45 °C. The hot water or steam and the heated water from heat exchanger 2 are then combined via the outlet lines 4 and 6 and flow to the consumers via the hot water line 7.It has proven advantageous to arrange a valve 8, preferably a thermostatic mixing valve or a control valve, between the outlet lines 4, 6, which regulates the flow rates so that the outgoing hot drinking water corresponds to the preset consumer temperature for hot water. This can be achieved either by means of a thermostatic mixing valve or by means of an electrically adjustable control valve that regulates the flow rate based on temperature sensors.

[0030] It is advantageous to have a safety valve 9 installed on the hot water pipe for safety purposes. The valve 9 is preferably designed as a solenoid valve or an electric motor-operated valve and closes when a maximum water temperature is exceeded to prevent the excessively hot water from flowing to the consumer. Preferably, a temperature sensor 10 is installed on the hot water pipe 7 to detect the temperature of the hot water. This sensor is connected to the safety valve 9, and the safety valve 9 closes when the temperature reading exceeds the preset maximum value. The valve can open after a predetermined period, once the hot water has cooled sufficiently, or upon a new temperature reading by the sensor 10, which detects when the temperature falls below the maximum preset value.The hot water or steam storage tank 5 is electrically operated and preferably has an independent potable water connection TW. Of course, the potable water connection can also be provided as a branch line via the potable water connection 3 of the decentralized water supply station. When using a steam storage tank 5, a water-steam mixer 8 is preferably used to regulate the mixing ratio between the heated potable water from the heat exchanger 2 and the steam from the steam storage tank 5. This mixer also adjusts itself autonomously via temperature sensors. Reference symbol list

[0031] 1 Decentralized water supply station 2 Heat exchanger 3 Drinking water connection 4 Hot water outlet 5 Hot water or steam storage tank 6 Hot water or steam storage tank outlet 7 Hot water pipe 8 Valve 9 Safety valve 10 Temperature sensor Primary side heat exchanger; Secondary side heat exchanger TWTrinkwasserversorgungsleitung HZ-VL-PRPrimary heating circuit flow HZ-RK-PRPrimary heating circuit return HZ-VL-SEKSSecondary heating circuit flow HZ-RK-SEKSSecondary heating circuit return

Claims

1. Decentralized water supply station (1) for heating and providing drinking water, comprising a heat exchanger (2) connected on the primary side (I) to a flow (HZ-VL-PR) and return (HZ-RL-PR) of the heating water, a drinking water connection (3) for connecting the secondary side (II) of the heat exchanger (2) to a drinking water supply line (TW), and a hot water outlet (4) for the heated drinking water arranged on the secondary side of the heat exchanger (2). characterized by the fact that the decentralized water supply station (1) includes a pressurized hot water storage tank (5) or a steam storage tank (5) on which a hot water or steam outlet (6) is arranged, which is connected to the hot water outlet (4) arranged on the secondary side of the heat exchanger (2) and the heated drinking water from the heat exchanger (2) is mixed with the hot water or steam and supplied to the consumers via a hot water pipe (7).

2. Decentralized water supply station (1) according to claim 1, characterized by the fact that a valve (8) is arranged between the hot water outlet (6) and the warm water outlet (4).

3. Decentralized water supply station (1) according to claim 2, characterized by the fact that the valve (8) is designed as a thermostatic mixing valve or control valve.

4. Decentralized water supply station (1) according to claim 1, characterized by the fact that a steam-water mixer (5) is arranged between the steam outlet (6) and the hot water outlet (4).

5. Decentralized water supply station (1) according to claim 1, characterized by the fact that the heat exchanger (2) is a water-to-water heat exchanger.

6. Decentralized water supply station (1) according to claim 1, characterized by the fact that the pressurized hot water storage tank (5) and the steam storage tank (5) are electrically heated or heated.

7. Decentralized water supply station (1) according to one of claims 1 to 6, characterized by the fact thatthe hot water pipe (7) has a safety valve (9) to completely open or close the hot water pipe (7).

8. Decentralized water supply station (1) according to one of claims 1 to 7, characterized by the fact that a temperature sensor (10) is arranged on the hot water pipe (7) for safety monitoring of the hot water temperature.

9. Method for heating and providing hot drinking water with a decentralized water supply station (1) according to any one of claims 1 to 8, comprising the following steps: preheating the drinking water in the secondary-side part (II) of a heat exchanger (2), wherein the heat energy is supplied to the heat exchanger (2) via a heat exchanger (2) connected on the primary side (I) to a flow and return (HZ-VL-PR, HZ-RL-PR) of the heating water, characterized by the fact that Hot water or steam is added to the drinking water heated by the heat exchanger (2) after the heat exchanger (2).

10. Method according to claim 9, characterized by the fact that The added hot water has a temperature > 100°C.

11. Method according to one of claims 9 or 10, characterized by the fact that Hot water is added to the heated drinking water via a thermostatic mixing valve (8) or a control valve (8).

12. Method according to one of claims 9 or 10, characterized by the fact that The addition of steam to the heated drinking water is carried out via a steam-water mixer (8).

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