EP0594020B1 - Installation for heating domestic water and for killing the legionella in this water - Google Patents

Abstract

The invention relates to an installation for heating domestic water and for killing the legionella in this domestic water, having a cold-water supply line (18) to a first heat exchanger (10), having a disinfecting-water circuit (1), which consists of a water heater (3), a charging pump (4), a domestic-water storage tank (5) and a buffer (6), and having a circulating-water circuit (2) with tapping points (12), a circulating line (13) and a circulating pump (14). The object of the invention is to provide an installation which, while being energy-efficient in operation, can also be used either considerably to reduce or else kill off the legionella present in the circulating-water circuit. This object is alternatively achieved by the fact that the domestic-water distributing line (1) is connected via a domestic-water collecting line (15), via a backflow preventer (16), a water-quantity limiter (17), the cold-water supply line (18) and also via an access line (23) with the charging pump (4), via the water heater (3) and the buffer (6) to form a complete circuit (1, 2). <IMAGE>

Description

The invention relates to a system for heating domestic water and for killing legionella in this domestic water with a cold water supply to a first heat exchanger for preheating the cold water supplied and for cooling the domestic water supplied via a domestic water outflow line from a disinfection water circuit heated to disinfection temperature, the Consists of a water heater, a loading pump, a domestic water storage tank and a buffer, the buffer in the conveying direction of the domestic water via the domestic water outlet line to the first heat exchanger and from there to the domestic water distribution line to the taps and a circulation line with a circulation pump in connection stands.

A system of this type is known from Figures 4, 4a and 8 to 10 of DE-PS 38 40 516. Although the system described therein fulfills its function for killing Legionella and is also characterized by an energy management operation, extensive studies have meanwhile found that Legionella cannot be avoided in the circulation water circuit. This circulation water cycle consists essentially of the process water distribution line to the taps, a circulation pump and a process water collection line. According to the results of these investigations, the reason for the formation of legionella despite loading this circulation water circuit with already disinfected water essentially lies in the fact that when the system is filled with cold water for the first time, legionella bacteria are introduced into the circulation water circuit from which they are used conventional means of thermal disinfection cannot be eliminated. This is because the thermal disinfection described in DE-PS 38 40 516 in column 1 in the third paragraph by gradually adjusting the temperature in the process water distribution line to 70 ° C in practice in large systems of the type mentioned in hospitals , Old people's homes, hotels and barracks cannot be reached with sufficient certainty after they have been filled for the first time or in the event of a breakdown using conventional means and procedures.

Starting from this state of the art, the invention has for its object to provide a system of the type mentioned, with which the legionella cells which have entered the circulation water circuit can either be considerably reduced or even killed while still operating in the energy industry.

This object is achieved in connection with the generic term mentioned at the outset according to a first alternative in that the Service water distribution line via a service water collecting line, via a backflow preventer, a water quantity limiter, the cold water supply line and an access line to the charge pump via the water heater and the buffer to form a complete circuit. Of course, the procedure is such that the disinfection temperature in the disinfection water circuit is constantly and permanently maintained, as a result of which this high temperature range and the associated lime precipitations remain restricted to a very local area of the entire system. Furthermore, despite the connection of the disinfection water circuit with the circulation water circuit to form an overall circuit, an energy management operation is maintained. As a result, the legionella present in the circulation water circuit as a result of the initial filling or as a result of a breakdown in operation can be introduced into the disinfection water circuit when there is no water and killed there. This significantly reduces the concentration of legionella in the circulation water circuit. If the entire system is used for a long period of time, the entire circulation water can be channeled through the disinfection water circuit several times, and ultimately Legionella bacteria can be completely destroyed. The aforementioned first alternative solution has the advantage of requiring only one heat exchanger.

According to a second alternative, the object on which the invention is based is achieved in connection with the generic term mentioned at the outset in that the first heat exchanger in a manner known per se via a flow connection line and a second heat exchanger with the process water distribution line to the taps via a process water Manifold, via a backflow preventer, a water flow limiter and via the second heat exchanger, a return connection line and via an access line to the charge pump via the water heater and the buffer to form an overall circuit. This alternative solution has several different control options due to the second heat exchanger.

Both alternative solutions have in common that the legionella-contaminated circulation water from the service water manifold is led via a backflow preventer and a water quantity limiter in the direction of the disinfection water circuit. The water flow limiter ensures that only such a large amount of circulation water is led from the service water manifold to the disinfection water circuit that a safe and constant disinfection temperature is always ensured by the charge pump and the water heater and a part of the charge pump the disinfection water circuit maintained and only the excess in the domestic water storage and / or the buffer a certain amount of enthalpy to be regulated from the disinfected water Disinfection water circuit transferred to the legionella-contaminated water from the circulation water circuit and can thus be included in the disinfection process again in terms of energy management. The backflow preventer ensures a clear flow direction in the entire circuit.

In the case of dispensing, the delivery rate of the charge pump, which goes beyond the delivery rate of the circulation pump, draws in the storage volume in the process water tank via a connection line to it and always heats it up again in the disinfection water circuit to the disinfection temperature. The delivery rate of the circulation pump (liters per minute) should not exceed 50% of the delivery rate of the charge pump. If the delivery capacity of the circulation pump were greater than 50% to a maximum of 100% of the charge pump, only a small part of the charge pump or the disinfection water circuit could be continuously fed into the process water storage tank, whereas the remaining amount would go directly into the Distribution circuit flows. Since, according to relevant publications, the legionella germ growth takes longer and a doubling can only take place in two to three hours, the above-described suction of the process water due to the excess delivery capacity of the charge pump compared to the circulation pump means that the legionella bacteria are removed from the circulation water circuit as well the cold water network is considerably reduced by disinfection and completely killed when the tap is not used for a long time.

To minimize the container effort and thus also the heat losses caused by radiation, it is particularly advantageous in terms of energy economy that the process water storage tank is also designed in a manner known per se as a reaction container, in the upper part of which there is a reaction volume as a buffer and in the lower part of which Storage volume is located. The buffer in the process water storage tank can be increased by one or more upstream buffers and / or the storage volume can be increased by one or more hot water storage tanks downstream in the flow direction of the charging pump.

In order to achieve a reliable disinfection water circuit and to include the circulation water circuit in an energy-efficient manner, several charge pumps in the disinfection water circuit are either assigned to a common water heater in parallel or each with its own water heater. Furthermore, in the disinfection water circuit, a plurality of charging pumps connected in parallel to one another are advantageously assigned to one or more reaction containers (s) connected in series or act on their own reaction containers connected in parallel with the other.

According to a particularly advantageous development of the invention, a cold water quantity control valve is arranged in the cold water supply line to the first heat exchanger, the second way of which is via a Intermediate line connected to the first heat exchanger and out of it via a connecting line like the third route with the access line to the domestic water storage tank. The cold water quantity control valve can advantageously be controlled by a temperature sensor which is arranged in the process water distribution line to the tapping points. The cold water quantity control valve in the cold water supply line ensures that water of a selectable, constant temperature flows into the circulation water circuit via the process water distribution line without having to increase the water temperature behind the hot water heater in the disinfection water circuit. The lowest permissible temperature in the disinfection water circuit immediately after the water heater is determined by the selected reaction volume of the buffer and by the expected germ concentration of the water to be heated. According to current knowledge, a disinfection temperature of + 65 ° C requires a reaction time of at least 15 minutes and a disinfection temperature of 70 ° C a reaction time of at least 4 minutes in order to be able to kill all Legionella bacteria in the disinfection water circuit.

In order to prevent overloading of the process water storage when tapping, a safety control valve is arranged in the cold water supply line in the flow direction upstream of the cold water flow control valve, which is located near the temperature sensor in the reaction vessel Process water outlet line can be throttled or closed if there is a minimum temperature of the storage volume in the reaction vessel that is to be set. As a result of this measure, non-disinfected cold water in the case of peak taps can be "shot through" via the access line into the process water storage tank and from there directly into the process water outflow line and in this way get into the circulation water circuit.

In large systems with the associated high circulation rates in the circulation water circuit, it is advantageous that a circulation water distribution valve is arranged in the direction of flow in front of the water quantity limiter and the backflow preventer in the process water collecting line, the third way of which is either via a first bypass line with the process water -Distribution line to the tapping points or via a second bypass line and a first circulation water quantity control valve with a heating coil which is arranged in the border area between the reaction volume and the storage volume in the reaction container. Via this circulation water distribution valve, it is ensured during removal that only the absolutely necessary amount of disinfected water with a selectable constant temperature can flow into the circulation water circuit via the process water distribution line.

The circulation water distribution valve for relieving the disinfection water circuit is advantageous either depending on the Disinfection temperature in the disinfection water circuit is regulated by a temperature sensor arranged between the charge pump and the storage volume or, depending on the time, by means of a timer such that the total circulation water quantity or only a part of this water is released from the circulation water circuit to the first heat exchanger and the remaining total circulation water or part quantity can be conveyed either via the first bypass line into the process water distribution line to the taps or via the second bypass line into the heating coil for renewed heating.

The first circulation water quantity control valve in the second bypass line can advantageously be regulated as a function of a temperature sensor in the process water outflow line from the reaction vessel.

The "hot water priority circuit" prescribed for hot water supply systems in residential construction requires that, in an advantageous development of the invention, the charge pump, the circulation pump and a heating medium pump in each case as a function of temperature sensors in the hot water outflow line, in the hot water storage tank, in the connecting line and in a heating medium line of the water heater can be switched or regulated. In the case of large systems and high demands on constant temperature in the circulation water circuit, the first alternative is in the Service water manifold in the flow direction upstream of the second heat exchanger, a second circulation water quantity control valve is arranged, the first way of which is connected to the water quantity limiter, the second way of which is connected to the second heat exchanger and the third way of which is the return connection line. This second circulation water quantity control valve is advantageously controlled by a temperature sensor in the process water distribution line to the tapping points.

Within the scope of the invention, the first heat exchanger can be acted upon by the process water outflow line and the cold water supply line either in cocurrent or in countercurrent. The choice of flow direction depends, among other things, on the required standard, the requirements for the constancy of the outlet temperature and the type of 1st or 2nd alternative solution. Also, to form a plurality of independent circulation water circuits, a number of process water distribution lines and process water collection lines, each with separate tapping points and circulation pumps, can be connected in parallel. In this case, additional water heaters can be used to run the circulation water circuits at different flow and return temperatures.

To form a compact device with regard to the disinfection water circuit, the first and second heat exchangers are on their own or together with the or the water heaters and charge pumps as well as one or more reaction vessels of the disinfection water circuit can be combined to form a compact device. Such a compact device is not only very space-saving, but can also be used retrospectively in existing systems for sanitizing hot water without special specialist knowledge of the assembly personnel.

A considerable further simplification is achieved by the first and / or the second heat exchanger consisting of a total of three compact partial heat exchangers, the first of which is connected to the domestic hot water outlet line at its entrance and to the domestic hot water distribution line at its outlet, the second at its Input with the cold water supply line and at its output with the access line to the hot water storage and the third partial heat exchanger with its input to the hot water collecting line and with its output to the access line to the hot water storage are connected without internal connecting lines.

According to a particularly advantageous development of the invention, in large systems the process water distribution line with the circulation pump and the process water manifold form a distribution circuit from which one or more branch lines branch off to secondary distribution devices.

According to a first embodiment, at least one first branch line branches off from the distributor circuit and, provided with electrical trace heating, leads to individual tapping points. Due to the individually adjustable trace heating, secured temperatures preventing the increase of Legionella as well as individual tapping temperatures at the tapping points are possible without adversely affecting the circulation water circuit and the disinfection water circuit.

In a second embodiment, at least one second branch line from the distribution circuit leads to a secondary distribution device with a high circulation capacity, the circulation heat losses via the third heat exchanger and also from a secondary distribution line to tapping points, a circulation pump, a UV radiation device and a third heat exchanger can be compensated from the distributor circuit via a hot water distributor valve.

According to a third embodiment, one or more branch lines lead from the distributor circuit to one or more self-contained, provided with tapping points and each consisting of a circulation pump, a circulation line and a fourth heat exchanger secondary circulation circuit with high circulation capacity, which via the fourth Heat exchanger with a secondary, consisting of a water heater and a reaction tank existing disinfection water circuit is connected, in which the circulation pump is also the charge pump.

• Fig. 1 Eine erste Ausführungsform nach der 1. Lösungsalternative mit einem ersten Wärmeübertrager und einem Kaltwassermengen-Regelventil in der Kaltwasserzuleitung,
• Fig. 2 eine Ausführungsform gemäß Fig. 1 mit einem ersten, aus drei Teilwärmeübertragern bestehenden Wärmeübertrager im Gesamtkreislauf,
• Fig. 3 eine Anlage nach der 1. Lösungsalternative mit einem ersten Wärmeübertrager, einem Kaltwassermengen-Regelventil und einem Zirkulationswasser-Verteilventil im Zirkulationswasser-Kreislauf,
• Fig. 4 eine Anlage gemäß der Ausführungsform von Fig. 3, jedoch mit einer Verbindung des Zirkulationswasser-Verteilventils über eine zweite Bypass-Leitung und einem Zirkulationswassermengen-Regelventil mit einer Heizschlange im Reaktionsbehälter,
• Fig. 5 eine Anlage ähnlich Fig. 4, jedoch mit zwei parallel zueinander angeordneten Wassererwärmern und Ladepumpen im Desinfektionswasser-Kreislauf, mehreren nachgeordneten Brauchwasser-Speichern, einem vorgeordneten Puffer und mehreren zueinander parallel geschalteten Zirkulationswasser-Kreisläufen mit getrennten Zirkulationspumpen,
• Fig. 6 eine Ausführungsform ähnlich Fig. 5, jedoch mit zwei parallel zueinander geschalteten Reaktionsbehältern mit je einem Zirkulationswassermengen-Regelventil und mit getrennten Wassererwärmern im Desinfektionswasser-Kreislauf,
• Fig. 7 eine Ausführungsform ähnlich Fig. 5, jedoch mit einem Verteiler-Kreislauf, aus welchem zwei Stichleitungen zu sekundären, in sich geschlossenen Verteilervorrichtungen mit elektrischen Begleitheizungen einerseits und mit einer UV-Strahlungseinrichtung andererseits,
• Fig. 8 eine Ausführungsform ähnlich Fig. 7, jedoch mit drei von einem Verteiler-Kreislauf abzweigenden Stichleitungen zu drei unterschiedlichen, in sich geschlossenen, sekundären Verteilervorrichtungen,
• Fig. 9 eine erste Ausführungsform nach der 2. Lösungsalternative mit einem ersten Wärmeübertrager und einem über eine Vorlauf-Verbindungsleitung damit verbundenen zweiten Wärmeübertrager zwischen Desinfektionswasser-Kreislauf und Zirkulationswasser-Kreislauf,
• Fig. 10 eine Ausführungsform ähnlich Fig. 9, jedoch mit einem Kaltwassermengen-Regelventil vor dem ersten Wärmeübertrager und einem Zirkulationswassermengen-Regelventil vor dem zweiten Wärmeübertrager,
• Fig. 11 eine Ausführungsform ähnlich Fig. 10, jedoch mit einem dazu unterschiedlich eingeordneten Kaltwassermengen-Regelventil und Zirkulationswassermengen-Regelventil sowie einem zusätzlichen Zirkulationswasser-Verteilventil in der Brauchwasser-Sammelleitung,
• Fig. 12 eine Ausführungsform ähnlich Fig. 11, jedoch ohne Zirkulationswasser-Verteilventil aber mit einer Heizmediumpumpe im Heizmedium-Kreislauf des Wassererwärmers sowie verschiedenen, zusätzlichen Temperaturfühlern,
• Fig. 13 eine Ausführungsform ähnlich Fig. 11, jedoch mit einer Verbindung des Zirkulationswasser-Verteilventils über eine zweite Bypass-Leitung zu zwei parallel geschalteten Brauchwasser-Speichern mit Heizschlange und einem nachgeordneten Brauchwasser-Speicher sowie mehreren zueinander parallel geschalteten Zirkulationswasser-Kreisläufen,
• Fig. 14 eine Ausführungsform ähnlich Fig. 11, jedoch mit einem kompakt zusammengefaßten ersten und zweiten Wärmeübertrager zu insgesamt drei Teilwärmeübertragern,
• Fig. 15 eine Ausführungsform ähnlich Fig. 14, jedoch ohne Zirkulationswasser-Verteilventil aber mit einer Heizmediumpumpe im Heizmedium-Kreislauf des Wassererwärmers und
• Fig. 16 eine Ausführungsform ähnlich Fig. 14, jedoch mit einer ersten Bypass-Leitung vom Zirkulationswasser-Verteilventil zur Brauchwasser-Verteilungsleitung, zwei zueinander parallel im Desinfektionswasser-Kreislauf angeordneten Wassererwärmern und Ladepumpen, einem vorgeordneten Puffer und zwei nachgeordneten Brauchwasser-Speichern.

Several embodiments of the invention are shown in the drawings. Show:

• 1 shows a first embodiment according to the first alternative solution with a first heat exchanger and a cold water quantity control valve in the cold water supply line,
• 2 shows an embodiment according to FIG. 1 with a first heat exchanger consisting of three partial heat exchangers in the overall circuit,
• 3 shows a system according to the first alternative solution with a first heat exchanger, a cold water quantity control valve and a circulation water distribution valve in the circulation water circuit,
• 4 shows a system according to the embodiment of FIG. 3, but with a connection of the circulation water distribution valve via a second bypass line and a circulation water quantity control valve with a heating coil in the reaction container,
• 5 shows a system similar to FIG. 4, but with two water heaters and charge pumps arranged in parallel in the disinfection water circuit, several downstream process water storage tanks, one upstream buffer and several circulation water circuits connected in parallel with separate circulation pumps,
• 6 shows an embodiment similar to FIG. 5, but with two reaction vessels connected in parallel to one another, each with a circulation water quantity control valve and with separate water heaters in the disinfection water circuit,
• 7 shows an embodiment similar to FIG. 5, but with a distributor circuit from which two branch lines to secondary, self-contained distributor devices with electrical trace heating on the one hand and with a UV radiation device on the other hand,
• 8 shows an embodiment similar to FIG. 7, but with three branch lines branching off from a distributor circuit to three different, self-contained, secondary distributor devices,
• Fig. 9 shows a first embodiment according to the second alternative solution with a first heat exchanger and one Flow connecting pipe connected to the second heat exchanger between the disinfection water circuit and the circulation water circuit,
• 10 shows an embodiment similar to FIG. 9, but with a cold water quantity control valve upstream of the first heat exchanger and a circulation water quantity control valve upstream of the second heat exchanger,
• 11 shows an embodiment similar to FIG. 10, but with a differently arranged cold water quantity control valve and circulation water quantity control valve and an additional circulation water distribution valve in the process water collecting line,
• 12 shows an embodiment similar to FIG. 11, but without a circulation water distribution valve but with a heating medium pump in the heating medium circuit of the water heater and various additional temperature sensors,
• 13 shows an embodiment similar to FIG. 11, but with a connection of the circulation water distribution valve via a second bypass line to two process water storage tanks connected in parallel with heating coil and a downstream service water storage tank as well as several circulation water circuits connected in parallel,
• 14 shows an embodiment similar to FIG. 11, but with a compactly combined first and second heat exchanger for a total of three partial heat exchangers,
• 15 shows an embodiment similar to FIG. 14, but without a circulation water distribution valve but with a heating medium pump in the heating medium circuit of the water heater and
• 16 shows an embodiment similar to FIG. 14, but with a first bypass line from the circulation water distribution valve to the process water distribution line, two water heaters and charge pumps arranged parallel to one another in the disinfection water circuit, a upstream buffer and two downstream process water storage tanks.

Each of the systems described below has a disinfection water circuit 1 and a circulation water circuit 2. The disinfection water circuit 1 is basically formed by a water heater 3, a charging pump 4, a domestic water storage 5 and a buffer 6, which in the present case is arranged in a manner known per se in the upper part of the domestic water storage 5, which is in this Case is also designed as a reaction container and in the lower part of which the storage volume 7 is located. This process water storage 5, which is also referred to below as a reaction container 5 with a buffer 6 and Storage volume 7 is designated, in the case shown, another memory 8 is arranged in series.

In the conveying direction of the process water according to the arrows drawn in, but for the sake of clarity, the buffer 6 is connected to the first heat exchanger 10 via the process water outlet line 9 and is connected to the first heat exchanger 10 via the process water distribution line 11 to the tapping points 12 and a circulation line 13 Circulation pump 14, via a service water collecting line 15, a backflow preventer 16 and a water quantity limiter 17 with the cold water supply line 18 in connection. In addition to a safety control valve 19, a cold water quantity control valve 20 is arranged in the cold water supply line 18. The cold water quantity control valve 20 is designed as a three-way valve, the first way 20a with the inflow of the cold water supply line 18, the second way 20b via an intermediate line 21 with the first heat exchanger 10 and out of this 10 via a connecting line 22 like the third way 20c with the Access line 23 to the domestic water storage 5 is connected. In this way, the circulation water circuit 2 is connected to the disinfection water circuit 1 to form an overall circuit 1, 2.

The cold water quantity control valve 20 can be controlled by a temperature sensor 24 which is arranged in the process water distribution line 11 to the tapping points 12. The safety control valve 19 in the cold water supply line 18 is controlled by a temperature sensor 25, which is arranged in the reaction vessel 5 near the process water outflow line 9 and throttles or closes the safety control valve 19 if the required minimum temperature of the disinfection water circuit 1 Storage volume 7 is below in the reaction container 5.

The water heater 3 in the disinfection water circuit 1 is acted upon by a heating medium line 26 with a heating medium control valve 27 which is controlled by a sensor 28 in the connecting line 29 between the water heater 3 and the domestic water storage 5.

According to an advantageous further development of the invention, when the pump is at rest, the delivery capacity of the charging pump 4, which goes beyond the delivery rate of the circulation pump 14, draws in and heats the storage volume 7 located in the service water store 5 via a connecting line 30 and the service water from the circulation water circuit 2 via the access line 23 it always in the disinfection water circuit 1 on the required disinfection temperature. As a result, the concentration of germs in the circulation water circuit 2 is considerably reduced in the event of a tapping rest and, under certain circumstances, is also completely destroyed in the event of longer tapping intervals.

In all of the figures described below, identical parts are always designated with the same reference numbers.

According to FIG. 2, the first heat exchanger 10 consists of a total of three compact partial heat exchangers 10a, 10b and 10c, of which the first 10a is connected to the process water outlet line 9 at its entrance and to the process water distribution line 11 at its outlet, the second 10b its input with the cold water supply line 18 and at its output with the access line 23 to the hot water tank 5 and the third partial heat exchanger 10c with its input and output are connected to the access line 23 to the hot water tank 5. The arrows indicate the flow directions. In the present case, the heating medium control valve 27 in the heating medium line 26 is controlled not only by the sensor 28 in the connecting line 29, but also by a further sensor 31 which is arranged in the process water distribution line 11. The cold water quantity control valve 20 of FIG. 1 is based on the exemplary embodiment of FIG. 2 the flow direction in the three partial heat exchangers 10a, 10b, 10c, the additional sensor 31 and the associated flexible control option can be dispensed with.

In all figures, a water quantity control valve 32 is also arranged between the charge pump 4 and the water heater 3, which in coordination with the water quantity limiter 17 in the process water collecting line 15 ensures that the charge pump 4 in the disinfection water circuit 1 depending on the size of the buffer 6 and the storage volume 7 circulates such a delivery quantity that all germs of Legionella in the process water are killed, which the buffer 6 leaves via the process water outlet line 9 in the direction of the circulation water circuit 2.

According to Fig. 3, a circulation water distribution valve 33 is arranged in the direction of flow in the flow direction upstream of the backflow preventer 16 and the water quantity limiter 17, the first path 33a and the second path 33b of which are connected to the process water collecting line 15, whereas its third path 33c is connected via a first bypass line 34 to the domestic water distribution line 11 to the tapping points 12. This circulation water distribution valve 33 is either depending on the disinfection temperature in the disinfection water circuit 1 between the charge pump 4 and the storage volume 7 in the connecting line 30 arranged temperature sensor 35 or depending on the time controlled by a timer 36. This regulation is carried out in such a way that the total amount of circulation water or only a portion of this water from the circulation water circuit 2 to the first heat exchanger 10 is only released when the disinfection water circuit 1, including the service water reservoir 5, is completely heated and thus the charging capacity largely for the Circulation amount is available. The rest of the total circulation water or partial quantity must flow via the first bypass line 34 into the process water distribution line 11 to the tapping points 12.

The other embodiment according to FIG. 4 differs from that according to FIG. 3 in that the circulation water distribution valve 33 is hydromechanically connected to a heating coil 39 by its third path 33c via a second bypass line 37 and a first circulation water quantity control valve 38, which is arranged in the boundary region 40 between the buffer volume 6 and the storage volume 7 in the reaction container 5. Here, the circulation water distribution valve 33 is controlled either via the temperature sensor 35 or the timer 36 such that the total amount of circulation water from the circulation water circuit 2 to the first Heat exchanger 10 is either released or can be conveyed into the heating coil 39 via the second bypass line 37. As a result, the charging capacity (disinfection capacity) is always completely available for heating the domestic water storage 5 during withdrawals. In this exemplary embodiment, the charge pump 4 can be switched either by a sensor 41 in the connecting line 30 and / or by a sensor 42 in the process water outlet line 9 and / or by a sensor 69 in order to meet the requirements of the process water priority circuit prescribed in residential construction. The first circulation water quantity control valve 38 consists of a three-way mixing valve, the first way 38a with the second bypass line 37, the second way 38b with the entry of the heating coil 39 into the hot water tank 5 and the third way 38c with the hot water Outgoing line 9 is connected.

The system according to FIG. 5 differs from the system according to FIG. 4 essentially in the following changes:

On the one hand, the circulation water circuit 2 is provided with a plurality of circulation water circuits 2a, 2b and 2c connected in parallel with one another with different circulation pumps 14a, 14b and 14c and separate water quantity limiters 43a, 43b and 43c.

Furthermore, the disinfection water circuit 1 contains two separate water heaters 3a and 3b, with separate heating medium control valves 27a, 27b in separate heating medium lines 26a, 26b and with separate charging pumps 4a and 4b, which are connected in parallel to one another. 4, a buffer 6a is now connected upstream via the connecting line 29 and a plurality of storage volumes 7a and 7b are arranged downstream of the storage volume 7 via the connecting line 30 and two further connecting lines 44, 46.

As can be seen from FIG. 5, the buffer volume 6, 6a can only leave the disinfection water circuit 1 via the connecting line 45 if the water flowing into the process water outlet line 9 has been exposed to the required disinfection temperature and the required disinfection time. The same applies correspondingly to the storage volumes 7a and 7b, which are connected to the storage volume 7 in the reaction container 5 via the connecting line 46. By means of these two additional process water reservoirs 7a and 7b, the disinfection water circuit 1 has been enlarged via the lines 30, 44 and 46 compared to the exemplary embodiment in FIG. 4. In both embodiments of Figures 4 and 5, the first circulation water quantity control valve 38 is dependent on a temperature sensor 47 in the Process water outlet line 9 regulated from the reaction tank 5.

It goes without saying that the charge pump 4 or the charge pumps 4a, 4b, as in the case shown in FIG. 4, each as a function of temperature sensors 41, 42 in the connecting line 30 and / or the process water outlet line 9 and / or the further temperature sensors 69 , 82 in the domestic water storage 5 and in a heating medium line 26 of the water heater 3 are switchable.

The further exemplary embodiment in FIG. 6 differs from the system in accordance with FIG. 5 essentially in that two reaction vessels 5a and 5b with separate first circulation water quantity control valves 38a and 38b are arranged in the disinfection water circuit 1. Each of the reaction containers 5a and 5b contains in its upper part a reaction volume 6a, 6b as a buffer and in its lower part a storage volume 7a, 7b, which is enlarged by the downstream service water storage 7c.

In FIGS. 7 and 8, the process water distribution line 11 together with the circulation pump 14 and the process water collection line 15 each form a distribution circuit 48, from which one or more branch lines 49, 50, 51, 52 form branch secondary manifolds 53 to 56. The first stub 49 leads to individual tapping points 12 which are provided with electrical trace heaters 57.

Furthermore, a second branch line 50 leads from the distribution circuit 48 to a secondary distribution device 54 with a high circulation capacity, the circulation water heat losses of which consist of a secondary distribution line 58 to tapping points 12, a circulation pump 59, a UV radiation device 60 and a heat exchanger 61 Heat exchangers 61 and a hot water distributor valve 62 from the distributor circuit 48 can be compensated.

8 lead from the distribution circuit 48 two further branch lines 51, 52 to several self-contained, provided with tapping points 12 and each a circulation pump 63, 64, a circulation line 65 and a heat exchanger 66 existing secondary distributor circuits 68, which via the Heat exchangers 66 are connected to a secondary disinfection water circuit 71 consisting of a water heater 67 and a reaction container 70, in which the circulation pumps 63, 64 are also the charging pumps. Here, before the circulation line 65 enters the heat exchanger 66 in the secondary distributor device 56 Another circulation water control valve 72 is arranged, which can be controlled depending on a temperature sensor 73.

According to an advantageous development of the invention, the circulation water control valve 72 is designed as a three-way valve which can be controlled via a timer 93 and the temperature sensor 73, the first route 72a with the circulation line 65, the second route 72b with the fourth heat exchanger 66 and the latter third route 72c is connected via a connecting line 90 to a connecting line 91 leading from the fourth heat exchanger 66 to the branch line 52, behind the connecting point 92 of which the temperature sensor 73 is arranged in the flow direction (see arrows). In this embodiment, the valve 72 can advantageously only flow as much circulation water through the connecting line 94 into the disinfection circuit 66, 67, 71, 70 in the daytime depending on the temperature sensor 73 via the path 72b as at the connecting point 92 from the lines 90 , 91 is required to ensure the target temperature at temperature sensor 73. In contrast, in the night hours outside the normal operating time in a time adjustable via the timer 93 via the circulation water control valve 72, the entire amount of circulation water can be passed via the connecting line 94 into the disinfection circuit 66, 67, 71, 70 and this total quantity is safely disinfected during this time until normal operation is initiated again either by switching off by the timer 93 or via a maximum flow temperature to be set on the temperature sensor 73 to the tapping points 12. Such a setting of the maximum temperature that is higher than the target temperature enables on the one hand a periodic reduction of any germs adhering to the inner pipe surfaces of the secondary distributor circuit 52-12 and an economical design of the fourth heat exchanger 66, since, in particular with large amounts of circulation water, the difference between the inlet temperature in the Distribution circuit 52, 12, 64, 72, 92, 90 and the return temperature on the first route 72a in the circulation water control valve 72 can be very low. As a result, the amount of water entering the fourth heat exchanger 66 from the connecting line 94 with a temperature of, for example, 45 ° C., the amount of hot water entering the fourth heat exchanger 66 from the line 95, for example 70 ° C., can only be increased to approx Cool down to 55 ° C and thereby cause a slowly increasing temperature in the distribution circuit 52, 12, 64, 72, 90, 92 to an adjustable maximum temperature.

Furthermore, by installing an electrically heated water heater 96 downstream of the water heater with control by a sensor 97 the temperature in the connecting line 71 can be raised to the temperature level necessary to kill the germs if the temperature of the heating medium at the water heater 67 is too low.

The embodiment according to FIG. 9 according to the second alternative solution differs from the first alternative solution according to FIG. 1 essentially in that now the first heat exchanger 10 in a manner known per se via a flow connecting line 74 and a second heat exchanger 75 with the Process water distribution line 11 to the tapping points 12, via a circulation line 13 with circulation pump 14 and via a process water collecting line 15, via a backflow preventer 16, a water quantity limiter 17 and also via the second heat exchanger 75, a return connection line 76 and via an access line 23 the domestic water storage 5 and the buffer 6 is connected to an overall circuit 1, 2. Furthermore, in contrast to FIG. 1, the cold water supply line 18 to the first heat exchanger 10 to the process water outflow line 9 is now connected in direct current. The cold water preheated in the first heat exchanger 10 leaves the latter via a connecting line 77 to the access line 23. The main difference between the embodiment of FIG. 9 resides in the addition of a second heat exchanger 75 and the elimination of the Cold water quantity control valve 20 of FIG. 1, which is particularly suitable for smaller systems with low requirements for the constancy and level of the outlet temperature.

In FIG. 10, compared to FIG. 9, a cold water quantity control valve 20 is arranged in the cold water supply line 18 and a second circulation water quantity control valve 78 is arranged in the process water collecting line 15 downstream of the water quantity limiter 17. With the two control valves 20, 78, both the amount of cold water and the amount of circulation water and thus the hot water outlet temperature can be selected and controlled. The control of the cold water quantity control valve 20 takes place via the temperature sensor 24 in the process water distribution line 11 and the control of the circulation water quantity control valve 78 by a temperature sensor 79, which is likewise arranged in the process water distribution line 11. This system is not only characterized by an extremely varied control option via the two control valves 20 and 78, but also includes the possibility that if one of the two control valves 20, 78 fails, the other can at least partially take over the function of the other.

The embodiment of FIG. 11 essentially results from a combination of the embodiment of FIG. 10 in conjunction with the circulation water quantity distribution valve 33 from FIG. 3. In the first heat exchanger 10, the cold water supply line 18 to the process water outlet line 9 is in direct current and in second heat exchanger 75 connected the flow connection line 74 to the process water collecting line 15 in countercurrent. In addition, the cold water quantity control valve 20 is arranged with its first path 20a and its second path 20b in the cold water supply line 18, on the other hand connected with its third path 20c via a connecting line 79 as a bypass to the connecting line 77. Furthermore, the circulation water quantity control valve 78 is arranged with its first path 78a and its second path 78b in the process water collecting line 15, on the other hand with its third path 78c it is connected to the return connection line 76 as a bypass via a connecting line 80. The circulation water quantity control valve 78 is controlled by a sensor 81 in the process water distribution line 11, which, however, is attached behind the connection of line 34 into line 11. The circulation water distribution valve 33 is regulated, as in the embodiment of FIG. 3, either via the sensor 35 or the timer 36.

The embodiment of FIG. 12 corresponds essentially to the embodiment of FIG. 11, but with the circulation water distribution valve 33 omitted. Furthermore, a heating medium pump 83 is now arranged in the heating medium circuit 86 of the water heater 3, which pump pump jointly or separately from the charging pump 4 and the circulation pump 14 can be regulated via the temperature sensor 84 in the connecting line 30 and / or the temperature sensor 85 in the domestic water storage 5 and / or the temperature sensor 82 in the flow of the heating medium circuit 86. By means of these circuits, which act on the charge pump 4, the heating medium pump 83 and the circulation pump 14 and are coupled to one another, the requirements of the service water priority circuit are met via the temperature sensors 82, 84 and 85.

The further embodiment according to FIG. 13 essentially consists of a combination of the embodiment of FIGS. 11 and 6. Accordingly, parts that correspond to it are also designated with the same reference numbers, without their function being discussed again. In the exemplary embodiment in FIG. 13, the circulation water distribution valve 33 is connected via a second bypass line 37 to the two reaction containers 5a, 5b connected in parallel to one another. Likewise, in the circulation water circuit 2 there are a total of three separate circulation water circuits 2a, 2b and 2c arranged parallel to each other.

The first heat exchanger 10 is connected to the second heat exchanger 75 and via the cold water quantity control valve 20 and the second circulation water quantity control valve 78 according to FIG. 11. This embodiment is also particularly suitable for large systems with high operational safety requirements and with circulating water in e.g. three separate circulation water circuits 2a, 2b, 2c with different circulation quantities or pressure levels.

The embodiment of FIG. 14 essentially results from a combination of the systems according to FIGS. 2, 3 and 12, the first and second heat exchangers 10, 75 now being combined to form a compact heat exchanger 10 similar to FIG a total of three partial heat exchangers 10a, 10b, 10c. The circulation water distribution valve 33 is arranged in the process water collecting line 15 as in FIG. 3 and is connected to the process water distribution line 11 via the first bypass line 34. The input and output of the first partial heat exchanger 10a is connected to the process water outlet line 9.

The cold water supply line 18 leads from the safety control valve 19 via the cold water quantity control valve 20 to the inlet into the partial heat exchanger 10b, the outlet of which is connected to the access line 23 via the connecting line 89 similar to the connecting line 77 according to FIG. 13.

The circulation water quantity control valve 78 is arranged with its two paths 78a and 78b in the process water collecting line 15 and is connected with its third path 78c via the line 87 to the entry of the partial heat exchanger 10a, from which this line via the connecting line 88 to the access line 23 is connected to the domestic water storage 5. With respect to the partial heat exchanger 10a, the partial heat exchanger 10b is connected in cocurrent and the partial heat exchanger 10c in countercurrent. Both the cold water quantity control valve 20 and the second circulation water quantity control valve 78 are regulated via the two temperature sensors 24 and 81, which are arranged in the process water distribution line 11. The circulation water distribution valve 33 is regulated, as in FIG. 11, either via the temperature sensor 35 in the connecting line 30 or via a timer 36. The hot water tank 8 is arranged downstream of the hot water tank 5.

Since the embodiments of FIGS. 2 and 14 each have a compact heat exchanger 10 composed of a total of three partial heat exchangers 10a, 10b, 10c have, which can be considered both only as the first 10 or only as the second 75 or as a combination of the first and second heat exchangers 10, 75, the embodiments of FIGS. 2 and 14 represent in a way a connecting embodiment between the two alternative solutions of subsidiary claims 1 and 2.

This also applies to the further embodiments of FIGS. 15 and 16.

The circuit of the compact heat exchanger 10 is arranged in FIG. 15 with respect to the cold water quantity control valve 20 and the second circulation water quantity control valve 78 according to FIG. 14, the circulation water distribution valve 33 from FIG. 14 being omitted. Furthermore, as in FIG. 12, a heating medium pump 83 is now arranged in the heating medium circuit 86, which, like the charging pump 4 and the circulation water pump 14, can be switched via the sensors 82, 84, 85.

The embodiment of FIG. 16 essentially consists of a combination of the embodiments of FIG. 15 with the embodiment of FIG. 5, parts which correspond to these figures being identified here with the same reference numerals. The embodiment according to FIG. 16 contains the same compact heat exchanger 10 with the cold water quantity control valve 20 and the second one 15, wherein the circulation water distribution valve 33 with the second bypass line 37 to the reaction container 5 is also arranged in the process water collecting line 15. 5, a buffer 6a is arranged upstream of this reactine container 5 and two storage volumes 7a, 7b are arranged downstream. This embodiment is characterized by a large buffer and storage capacity, by a plurality of circulation water circuits 2a, 2b, 2c connected in parallel with one another and by the compact heat exchanger 10 with its various control options. This embodiment is also suitable for large systems with both large circulation water and circulating water quantities. The connection and disconnection options of the circulation water circuits 2a, 2b, 2c, as well as the storage volumes 7a and 7b and the upstream buffer 6a in the disinfection water circuit 1, as well as the parallel-connected charging pumps 4a and 4b with the water heaters 3a and 3b connected in parallel an extremely energy-efficient and flexible operation.

It goes without saying that there are still further possible combinations between the embodiments of FIGS. 1 to 16, which, however, do not leave the principle of the invention according to the dependent claims 1 and 2.

Reference symbol list:

Disinfection water circuit

1

Circulation water circuits

2, 2a, 2b, 2c

Water heater

3, 3a, 3b, 67

Charge pump

4, 4a, 4b

Process water storage tank or reaction tank

5, 8, 5a, 5b;

buffer

6, 6a, 70

Storage volume

7, 7a, 7b, 7c

Process water outlet pipe

9

Heat exchanger

10, 61, 66, 75

Partial heat exchanger

10a, 10b, 10c

Service water distribution line

11

Taps

12th

Circulation line

13

Circulation pumps

14, 59, 63, 64

Process water manifold

15

Backflow preventer

16

Water flow limiter

17th

Cold water supply

18th

Safety control valve

19th

Cold water flow control valve

20th

Paths of the cold water quantity control valve 20

20a, 20b, 20c

Intermediate line

21

Connecting lines

22, 29, 30, 44, 45, 46, 77, 79, 80, 87, 88, 89

Access line

23

Temperature sensor

24, 25, 28, 31, 35, 41, 42, 47, 69, 73, 79, 81, 82, 84, 85, 86

Heating medium line

26

Heating medium control valve

27

Water flow control valve

32

Circulating water distribution valve

33

Routes of the circulation water distribution valve 33

33a, 33b, 33c

first bypass line

34

Timer

36

second bypass line

37

first circulation water quantity control valve

38

Paths of the first circulation water quantity control valve 38

38a, 38b, 38c

Heating coil

39

Border area

40

Water flow limiter

43a, 43b, 43c

Distribution circuit

48

Stub lines

49, 50, 51, 52

Distribution devices

53, 54, 55, 56

Trace heating

57

Distribution line

58

UV radiation device

60

Hot water distribution valve

62

Circulation line

65

secondary distribution circuit

68

secondary disinfection water cycle

71

Flow connecting line

74

Return connection line

76

second circulation water quantity control valve

78

Routes of the circulation water quantity control valve 78

78a, 78b, 78c

Heating medium pump

83

Heating medium circuit

86

Claims (28)

1. Installation for the purpose of raising the temperature of service water and for destroying legionelle in this service water comprising a cold water supply duct (18) leading to a first heat exchanger (10) for preheating the cold water supplied and for the purpose of cooling the service water supplied via a service water output duct (9) from a water disinfecting circuit (1) which has been heated to disinfecting temperature and which consists of a water heater (3), a charge pump (4), a service water storage device (5) and a buffer (6), wherein in the direction in which the service water is being conveyed the buffer (6) is connected via the service water output duct (9) to the first heat exchanger (10) and from there to the service water distribution duct (11) leading to the dispensing points (12) and a circulation duct (13) having a circulating pump (14), characterised in that the service water distribution duct (11) is connected via a service water collecting duct (15), via a non-return device (16), a water quantity limiter (17), the cold water input duct (18) as well as via an input duct (23) to the charge pump (4) via the water heater (3) and to the buffer (6) to form an entire circuit (1,2).
2. Installation for the purpose of raising the temperature of service water and for destroying legionelle in this service water comprising a cold water supply duct (18) leading to a first heat exchanger (10) for preheating the cold water supplied and for the purpose of cooling the service water supplied via a service water output duct (9) from a water disinfecting circuit (1) which has been heated to disinfecting temperature and which consists of a water heater (3), a charge pump (4), a service water storage device (5) and a buffer (6), wherein in the direction in which the service water is being conveyed the buffer (6) is connected via the service water output duct (9) to the first heat exchanger (10) and from there to a service water distribution duct (11) leading to the dispensing points (12) and a circulation duct (13) having a circulating pump (14), characterised in that the first heat exchanger (10) is connected via a flow connecting duct (74) and a second heat exchanger (75) to the service water distribution duct (11) leading to the dispensing points (12), via a service water collecting duct (15), via a non-return device (16), a water quantity limiter (17) as well as via the second heat exchanger (75), a return connecting line (76) and via an input line (23) to the charge pump (4) via the water heater (3) and to the buffer (6) to form an entire circuit (1, 2).
3. Installation according to claim 1 or 2, characterised in that when the dispensing points are not in use the carrying capacity of the charge pump (4) which exceeds the carrying capacity of the circulating pump (14) draws in the stored volume (7) located in the service water storage device (5) via a connecting duct (30) into said storage device and constantly raises the temperature of the volume in the disinfecting circuit (1) again to disinfecting temperature.
4. Installation according to any one of claims 1 to 3, characterised in that the service water storage device (5) is formed in a manner known per se simultaneously as a reaction vessel (5) in whose upper portion is located a reaction volume (6) as a buffer (6) and in whose lower portion is located the stored volume (7).
5. Installation according to any one of claims 1 to 4, characterised in that the buffer (6) located in the service water storage device (5) is enlarged by virtue of one or several buffers (6, 6a) arranged upstream and/or the stored volume (7) is enlarged by virtue of one or several warm water storage devices (5, 7a, 7b, 7c, 8) arranged downstream in the flow direction of the charge pump (4, 4a, 4b).
6. Installation according to any one of claims 1 to 5, characterised in that in the disinfecting circuit (1) a plurality of charge pumps (4a, 4b) are allocated either connected in parallel to a common water heater (3) or to a dedicated water heater (3a, 3b) respectively.
7. Installation according to any one of claims 1 to 6, characterised in that in the water disinfecting circuit (1) a plurality of parallel-connected charge pumps (4a, 4b) are allocated to one or several reaction vessels (5, 5a, 5b) connected in series or in each case charge a dedicated reaction vessel (5a, 5b) which is connected in parallel to the other respective reaction vessel.
8. Installation according to claim 1 and 3 to 7, characterised in that in the cold water supply duct (18) the first heat exchanger (10) is allocated a cold water quantity control valve (20) whose second branch (20b) is connected via an intermediate duct (21) to the first heat exchanger (10) and from there (10) via a connecting duct (22) such as the third branch (20c) to the input duct (23) leading to the service water storage device (5).
9. Installation according to claim 8, characterised in that the cold water quantity control valve (20) can be controlled by a temperature sensor (24) which is arranged in the service water distribution duct (11) leading to the dispensing points (12).
10. Installation according to any one of claims 1 to 9 to 12 [sic] characterised in that a safety control valve (19) is arranged in the cold water supply duct (18) in the flow direction before the cold water quantity control valve (20), which safety control valve can be restricted or closed by a temperature sensor (25) in the reaction vessel (5) in the proximity of the service water output duct (9) in the event that in the water disinfecting circuit (1) the lowest permissible disinfecting temperature of the stored volume (7) in the reaction vessel (5) is not achieved.
11. Installation according to any one of claims 1 to 10, characterised in that in the flow direction before the water quantity limiter (17) and the non-return device (16) a circulating water distribution valve (33) is disposed in the service water collecting duct (15), the third branch (33c) of the said valve being connected either via a first bypass duct (34) to the service water distribution duct (11) leading to the dispensing points (12) or via a second bypass line (37) and a first circulating water quantity control valve (38) to a heating coil (39), which heating coil is disposed in the boundary region (40) between the reaction volume (6) and the stored volume (7) in the reaction vessel (5).
12. Installation according to claim 11, characterised in that the circulating water distribution valve (33) can be controlled either in response to the disinfecting temperature in the water disinfecting circuit (1) by a temperature sensor disposed between the charge pump (4) an'd the stored volume (7) or in response to the time via a time switch (36) in such a manner that the total quantity of circulating water or only a partial quantity of this water is to be released from the circulating water circuit (2) to the first heat exchanger (10) and the remaining total or partial quantity of circulating water can be conveyed either via the first bypass duct (34) into the service water distribution duct (11) leading to the dispensing points (12) or via the second bypass duct (37) into the heating coil (39).
13. Installation according to any one of claims 1 and 3 to 13 characterised in that the first circulating water quantity control valve (38) in the second bypass duct (37) can be controlled in dependence upon a temperature sensor (47) in the service water output duct (9) out of the reaction vessel (5).
14. Installation according to any one of claims 1 to 13, characterised in that the charge pump (4), the circulating pump (14) and a heating medium pump (83) can be switched in each case in dependence upon temperature sensors (41, 42, 69, 82, 84, 85) in the service water output duct (9), in the service water storage device (5) in the connecting duct (30) and in a heating medium duct (26)of the water heater (3).
15. Installation according to any one of claims 2 to 14 and 16 to 18, characterised in that in the service water collecting duct (15) in the flow direction before the second heat exchanger (75) there is located a second circulating water quantity control valve (78) whose first branch (78a) is connected to the water quantity limiter (17) and whose second branch (78b) is connected to the second heat exchanger (75) and whose third branch (78c) is connected to the return connecting duct (76).
16. Installation according to claim 15, characterised in that the second circulating water quantity control valve (78) can be controlled by a temperature sensor (79, 81) in the service water distribution duct (11) leading to the dispensing points (12).
17. Installation according to claims 1 to 16, characterised in that the first heat exchanger (10) can be influenced by the service water output duct (9) and the cold water duct (18) either in parallel flow or reverse flow.
18. Installation according to any one of claims 1 to 17, characterised in that a plurality of service water distribution ducts (11) and service water collecting ducts (15) having respective separate dispensing points (12) and circulating pumps (14a, 14b, 14c) are connected in parallel with each other to form separate circulating water circuits (2a, 2b, 2c).
19. Installation according to any one of claims 2 to 18, characterised in that the first and the second heat exchanger (10, 75) can themselves or together with the one or several water heaters (3, 3a, 3b) and charge pumps (4, 4a, 4b) as well as with one or several reaction vessels (5a, 5b) of the disinfecting circuit (1) be combined to form a compact unit .
20. Installation according to any one of claims 1 to 19, characterised in that the first and/or the second heat exchanger (10, 75) consists in total of three compact combined partial heat exchangers (10a, 10b, 10c) of which the first (10a) is connected at its input to the service water output duct (9) and at its output to the service water distribution line (11), the second (10b) at its input to the cold water supply duct (18) and at its output to the input duct (23) leading to the service water storage device (5) and the third partial heat exchanger (10c) is connected at its input to the service water collecting duct (15) and at its output to the input duct (23) leading to the service water storage device (5).
21. Installation according to claim 20, characterised in that the second circulating water quantity control valve (78) is disposed with its first branch (78a) and third branch (78c) between the water quantity limiter (17) and the input to the third partial heat exchanger (10c) whereas the second branch (78b) is connected to the input duct (23).
22. Installation according to any one of claims 1 to 21, characterised in that the service water distribution duct (11) forms with the circulating pump (14) and the service water collecting duct (15) a distribution circuit (48) from which one or several stub ducts (49 to 52) branch off towards secondary distributing devices (53 to 56).
23. Installation according to claim 22, characterised in that at least a first stub duct (49) branches off from the distribution circuit (48), the said stub duct being provided with auxiliary electrical heaters (57) and leading to individual dispensing points (12).
24. Installation according to claim 22, characterised in that from the distribution circuit (48) at least one second stub duct (50) leads to a secondary distributing device (54) which has a high circulating capacity and consists of a secondary distribution duct (58) leading to the dispensing points (12), a circulating pump (59), a UV-radiating device (60) and a third heat exchanger (61), whose circulation heat losses can be compensated by way of the third heat exchanger (61) as well as via a warm water distributing valve (62) from the distribution circuit (48).
25. Installation according to claim 22, characterised in that from the distribution circuit (48) one or several stub ducts (51, 52) lead to one or several secondary distribution circuits (68) which are closed in themselves, are provided with dispensing points (12) and consist in each case of a circulating pump (63, 64), a circulation duct (65) and a fourth heat exchanger (66) and which are connected by way of the fourth heat exchanger (66) to a secondary disinfecting water circuit (71) which consists of a water heater (67) and a reaction vessel (70) and in which the circulating pump (63, 64) is also the charge pump.
26. Installation according to daim 25, characterised in that before the inlet of the circulation duct (65) a further circulation water control valve (72), which can be controlled in dependence upon a temperature sensor (73), Is disposed in the fourth heat exchanger (66).
27. Installation according to claim 25 and 26, characterised in that the water circulation water control valve (72) is in the form of a three-way valve which can be controlled by way of a time switch (93) and the temperature sensor (73), the first path (72a) of the said three-way valve being connected to the circulation duct (65), the second path (72b) being connected to the fourth heat exchanger (66) and the third path (72c) being connected by way of a connecting duct (90) to a connecting duct (91) leading from the fourth heat exchanger (66) to the stub duct (52), and the temperature sensor (73) is disposed in the flow direction behind the connection point (92) of the connecting duct (91).
28. Installation according to claims 25 to 27, characterised in that a water heater (96) and the temperature sensor thereof (97) is connected downstream of the water heater (67) in the absence of an increasing temperature level of the heating medium.

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