Three-conductor and four-conductor system for saving energy in connection with district heat

Abstract

The patent application relates to a district-heat consumer plant which is capable of being linked to a district-heat network and which comprises at least one heat-consumer which is capable of being supplied with heat from the district-heat network, the district-heat consumer plant comprising a port via which the district-heat consumer plant is capable of being linked to a district-heat reflux of the district-heat network, in order to withdraw heat from the district-heat reflux for the purpose of supplying the at least one heat-consumer. The patent application further relates to a district-heat network, to which a district-heat consumer plant is capable of being linked, the district-heat network comprising a district-heat reflux, and the district-heat reflux comprising a port for the district-heat consumer plant, in order to supply the district-heat consumer plant with heat from the district-heat reflux. Lastly, the patent application relates to a district-heat system which comprises a district-heat consumer plant and a district-heat network.

Claims

1. A district-heat consumer plant, which is linked to a district-heat network having a district-heat afflux and a district-heat reflux, comprising: at least one heat-consumer which is supplied with heat from the district-heat network; an afflux supply port via which the district-heat consumer plant is linked to the district-heat afflux of the district-heat network; an afflux transfer station comprising an afflux heat exchanger, the afflux heat exchanger comprising a primary side and a secondary side, a primary afflux of the afflux heat exchanger being in flow communication with the afflux supply port, in order to withdraw heat from the district-heat afflux; and a reflux return port in flow communication with a primary reflux of the afflux heat exchanger via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network; and a reflux supply port via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network; a reflux transfer station comprising a reflux heat exchanger, the reflux heat exchanger comprising a primary side and a secondary side, a primary afflux of the reflux heat exchanger being in flow communication with the reflux supply port, in order to withdraw heat from the district-heat reflux; and a reflux return port in flow communication with the heat exchanger via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network, and a mixing valve, wherein a secondary afflux of the afflux heat exchanger and a secondary afflux of the reflux heat exchanger are linked to the mixing valve, the mixing valve being configured for supplying heat to the at least one heat consumer.

2. A district-heat consumer plant of claim 1, wherein the at least one heat-consumer is a low-energy consumer system or a low-temperature system.

3. A district-heat consumer plant of claim 2, wherein the at least one heat-consumer is a low-energy consumer system selected from an underfloor heating system, a wall heating system and a ceiling heating system.

4. A district-heat consumer plant of claim 2, wherein the at least one heat-consumer is a low-temperature system selected from a low energy house, a low-temperature heating plant, and a low-temperature de-aerating plant.

5. A district-heat consumer plant of claim 1 further comprising a feed pump in flow communication with the district heat-reflux and with the reflux supply port and positioned downstream of the reflux supply port.

6. A district-heat consumer plant of claim 1, wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

7. A district-heat consumer plant of claim 1, wherein the reflux return port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

8. A district-heat consumer plant of claim 1, wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow, and wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

9. A district-heat network having a district-heat afflux and a district-heat reflux, comprising: at least one heat-consumer; an afflux supply port via which a district-heat consumer plant is linked to the district-heat afflux of the district-heat network; an afflux transfer station comprising an afflux heat exchanger, the afflux heat exchanger comprising a primary side and a secondary side, a primary afflux of the afflux heat exchanger being in flow communication with the afflux supply port, in order to withdraw heat from the district-heat afflux; and a reflux return port in flow communication with a primary reflux of the afflux heat exchanger via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network; and a reflux supply port via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network; a reflux transfer station comprising a reflux heat exchanger, the reflux heat exchanger comprising a primary side and a secondary side, a primary afflux of the reflux heat exchanger being in flow communication with the reflux supply port, in order to withdraw heat from the district-heat reflux; and a reflux return port in flow communication with a primary reflux of the reflux heat exchanger via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network, and a mixing valve, wherein a secondary afflux of the afflux heat exchanger and a secondary afflux of the reflux heat exchanger are linked to the mixing valve, the mixing valve being configured for supplying heat to the at least one heat consumer.

10. A district-heat network of claim 9 further comprising a connecting node in place of the reflux return port in flow communication with the afflux heat exchanger, the connecting node being in flow communication with the afflux heat exchanger and with the reflux heat exchanger and also being in flow communication with a reflux return port whereby the flow from the afflux heat exchanger and the flow from the reflux heat exchanger combine prior to the reflux return port via which the district-heat consumer plant is linked to the district-heat reflux of the district-heat network.

11. A district-heat network of claim 10, wherein the reflux return port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

12. A district-heat network of claim 9, wherein the at least one heat-consumer is a low-energy consumer system or a low-temperature system.

13. A district-heat network of claim 12, wherein the at least one heat-consumer is a low-energy consumer system selected from an underfloor heating system, a wall heating system and a ceiling heating system.

14. A district-heat network of claim 12, wherein the at least one heat-consumer is a low-temperature system selected from a low energy house, a low-temperature heating plant, and a low-temperature de-aerating plant.

15. A district-heat network of claim 9 further comprising a feed pump in flow communication with the district heat-reflux and with the reflux supply port and positioned downstream of the reflux supply port.

16. A district-heat network of claim 9, wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

17. A district-heat network of claim 9, wherein the reflux return port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

18. A district-heat network of claim 9, wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow, and wherein the reflux supply port is a line within the district-heat reflux inclined at an angle of about 45° relative to the direction of flow.

19. A district-heat network of claim 9, wherein the mixing valve is configured for admixing medium heated by the afflux heat exchanger to the medium heated by the reflux heat exchanger.

20. A district-heat network of claim 10, wherein the district-heat consumer plant is constructed as a three-conductor system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments will be described in more detail in the following on the basis of three exemplary embodiments represented in the drawings, to which, however, the patent application is not restricted.

(2) FIG. 1 shows a district-heat system known from the state of the art with a district-heat consumer plant which is linked to a district-heat network;

(3) FIG. 2 shows a district-heat system with a district-heat consumer plant linked to a district-heat network and with three ports to the district-heat network;

(4) FIG. 3 shows a district-heat system with a district-heat consumer plant linked to a district-heat network with a heat-consumer system and with three ports to the district-heat network;

(5) FIG. 4 shows the port of the primary afflux of the first heat-exchanger and also of the primary reflux of the first and second heat-exchangers to the district-heat reflux;

(6) FIG. 5 shows a district-heat system with a district-heat consumer plant linked to a district-heat network with three ports to the district-heat network in a further embodiment;

(7) FIG. 6 shows a district-heat system with a district-heat consumer plant linked to a district-heat network with four ports to the district-heat network;

(8) FIG. 7 shows a district-heat system with a district-heat consumer plant linked to a district-heat network with a heat-consumer system and with four ports to the district-heat network; and

(9) FIG. 8 shows a district-heat consumer plant with four ports to the district-heat network in a further embodiment.

DETAILED DESCRIPTION

(10) In the following description of four preferred embodiments of the present patent application, identical reference symbols denote identical or comparable components.

(11) A district-heat system 1 known from the state of the art with a district-heat consumer plant 10 linked to a district-heat network 60 is represented in FIG. 1. The district-heat consumer plant 10 comprises a port 98C via which the district-heat consumer plant 10 is linked to a district-heat afflux 61 of the district-heat network 60, in order to withdraw heat from the district-heat afflux 61. In addition, the district-heat consumer plant 10 comprises a further port 98B via which the district-heat consumer plant 10 is linked to a district-heat reflux 63. Equally, the district-heat afflux 61 of the district-heat network 60 comprises a port 99C, and the district-heat reflux 63 comprises a port 99B for the district-heat consumer plant 10, in order to supply the district-heat consumer plant 10 with heat from the district-heat afflux 61. Furthermore, the district-heat consumer plant 10 comprises an afflux transfer station 43, which is of the type of a transfer station in order to withdraw heat from the district-heat afflux 61 of the district-heat network 60 via the afflux transfer station 43. The afflux transfer station 43 comprises shut-off valves 27A, bleed valves 26A, manometers 28A, a differential-pressure regulator 22A, a calorimeter 29A and also a motor-driven regulating valve 25A.

(12) In the case of the district-heat consumer plant 10, a second heat-exchanger 40 is linked via a primary afflux 52 to the district-heat afflux 61 and via a primary reflux 54 to a district-heat reflux 63 of the district-heat network 60. The primary afflux 52 of the second heat-exchanger 40 is linked to the district-heat afflux 61 via the motor-driven regulating valve 52 and two serially arranged shut-off valves 27A. Via the motor-driven regulating valve 25A the supply of the medium being conducted in the district-heat afflux 61 is regulated in such a way that the medium flows only in the event of heat demand by the second heat-exchanger 40. The primary reflux 54 of the second heat-exchanger 40 is linked to the district-heat reflux 63 via two serially arranged shut-off valves 27A. Between the two shut-off valves 27A of the primary reflux 54 and also of the primary afflux 52 of the second heat-exchanger 40 a bleed valve 26A is arranged in each instance. In addition, between the shut-off valve 27A, which faces towards the second heat-exchanger 40, and the second heat-exchanger 40 a manometer 28A is arranged in each instance on the primary afflux 52 and on the primary reflux 54, in order to indicate the pressure within the primary afflux 52 and within the reflux 54. This manometer 28A is arranged on the primary afflux 52 between the shut-off valve 27A and the motor-driven regulating valve 25A. Between primary afflux 52 and primary reflux 54 of the second heat-exchanger 40 in addition a differential-pressure regulator 22A and also a calorimeter 29A are arranged. The district-heat consumer plant 10 is accordingly connected to the district-heat network 60 via a calorimeter 29A. The differential-pressure regulator 22A and also the calorimeter 29A are located, as are also the manometers 28A, between the shut-off valve 27A, which faces towards the second heat-exchanger 40, and the second heat-exchanger 40, the calorimeter 29A being located between the second heat-exchanger 40 and the differential-pressure regulator 22A. The motor-driven regulating valve 25A is arranged between the port of the calorimeter 29A and the second heat-exchanger 40. Arranged parallel to the calorimeter 29A is a shut-off valve 27A.

(13) On the secondary side the second heat-exchanger 40 is linked to a heat-consumer system 15 via a secondary afflux 55 and a secondary reflux 57, in order to supply a heat-consumer 13 and a drinking-water heater 80 with heat. For this purpose, the secondary afflux 55 is linked to an afflux 17 of the heat-consumer system 15, and the secondary reflux 57 is linked to a reflux 19 of the heat-consumer system 15. The heat-consumer 13 and the drinking-water heater 80 are in each instance linked to the afflux 17 of the heat-consumer system 15 via a pump 23. The cold drinking water to be heated is supplied to the drinking-water heater 80 via a cold-drinking-water inlet 90, is heated in the former, and leaves the drinking-water heater 80 as hot drinking water via the hot-drinking-water outlet 93.

(14) Such a system is also designated as a two-conductor system, since the district-heat consumer plant 10 is linked to a district-heat network 60 via two ports, namely the primary afflux 51 and the primary reflux 53. In such a system, heat is transferred from the district-heat afflux 61 of the district-heat network 60 to the heat-consumer 13 via the second heat-exchanger 40. In such a district-heat consumer plant 10 constructed as a two-conductor system there may be a risk that the temperature of the medium being conducted in the district-heat reflux 63 rises considerably. This may be detrimental to an economical operation of the district-heat network 60.

(15) The first exemplary embodiment will be elucidated in the following on the basis of FIGS. 2 to 4. In FIG. 2 a schematic representation is shown of a district-heat system 1 with a district-heat network 60 and with a district-heat consumer plant 10 with three ports to the district-heat network 60 for the purpose of supplying heat to heat-consumers 13 from the district-heat network 60. FIG. 3 shows a schematic representation of a district-heat system with a district-heat network 60 and with a district-heat consumer plant 10 with a heat-consumer system 15 and with three ports to the district-heat network 60. In FIG. 4 a schematic representation of the port of the primary afflux 51 of the first heat-exchanger 30 and also of the primary reflux 53 of the first heat-exchanger 30 and of the primary reflux 54 of the second heat-exchanger 40 to the district-heat reflux 63 is represented. In the exemplary embodiment shown in FIGS. 2 to 4 it is a question of a three-conductor system which is supplied with heat via a district-heat network 60. For this purpose, a heated medium is conveyed from a district heating station 67 through a district-heat pump 69 via the district-heat afflux 61 to the district-heat consumer plant 10 which is constructed as a three-conductor system.

(16) The district-heat consumer plant 10 comprises four heat-consumers 13 and also a drinking-water heater 80 constructed as a heat-consumer 13, which are capable of being supplied with heat from the district-heat network 60. The district-heat consumer plant 10 comprises a port 98A via which the district-heat consumer plant 10 is linked to a district-heat reflux 63 of the district-heat network 60, in order to withdraw heat from the district-heat reflux 63 for the purpose of supplying it to the heat-consumers 13. Furthermore, the district-heat consumer plant 10 comprises a port 98B via which the district-heat consumer plant 10 is linked to the district-heat reflux 63. Via the port 98B, a medium that was withdrawn from the district-heat reflux 63 via the port 98A can again be routed into the district-heat reflux 63. The district-heat reflux 63 of the district-heat network 60 comprises a port 99A for the district-heat consumer plant 10, in order to supply the district-heat consumer plant 10 with heat from the district-heat reflux 63. The district-heat reflux 63 further comprises a port 99B for the district-heat consumer plant 10. Via the port 99B, a medium that was withdrawn from the district-heat reflux 63 via the port 99A can again be routed into the district-heat reflux 63.

(17) Furthermore, the district-heat consumer plant 10 comprises a reflux transfer station 33, which is of the type of a transfer station in order to withdraw heat from the district-heat reflux 63 via the reflux transfer station 33. In order to transfer heat from the district-heat reflux 63 to heat-consumers 13, the district-heat consumer plant 10 comprises a first heat-exchanger 30 with a primary afflux 51 which is linked to the district-heat reflux 63 of the district-heat network 60 via the reflux transfer station 33. The primary afflux 51 of the first heat-exchanger 30 is in this case linked via the port 98A of the district-heat consumer plant 10 to the port 99A of the district-heat network 60 and consequently to the district-heat reflux 63. Furthermore, the first heat-exchanger 30 comprises a primary reflux 53 which is linked to the district-heat reflux 63 via the reflux transfer station 33. The primary reflux 53 of the first heat-exchanger 30 is in this case linked via the port 98B of the district-heat consumer plant 10 to the port 99B of the district-heat network 60 and consequently to the district-heat reflux 63. The district-heat consumer plant 10 accordingly comprises a first heat-exchanger 30 with a primary afflux 51 and with a primary reflux 53, the primary afflux 51 and the primary reflux 53 of the first heat-exchanger 30 being linked to the district-heat reflux 63 via the reflux transfer station 33, in order to withdraw heat from the district-heat reflux 63. The reflux transfer station 33 comprises shut-off valves 27B, bleed valves, manometers, a differential-pressure regulator, a calorimeter 29B and also a motor-driven regulating valve, which for reasons of representation are only shown in part in FIGS. 2 and 3 and which are interconnected as represented in FIG. 1.

(18) The primary afflux 51 and the primary reflux 53 of the first heat-exchanger 30 are linked in such a way to the district-heat reflux 63 that the port 98B is situated downstream of the port 98A of the district-heat consumer plant 10 in the direction of flow 65. Equally, the port 99B is situated downstream of the port 99A of the district-heat reflux 63 in the direction of flow 65. In this case, between the port 98B, 99B and the port 98A, 99A a throttle valve 20 is arranged in the district-heat reflux 63. By means of this throttle valve 20, the flow pressure in the district-heat reflux 63 can be controlled in such a way that the pressure and/or the flow velocity in the primary afflux 51 of the first heat-exchanger 30 is increased. By this means, the heat is transferred more effectively to the heat-consumers 13.

(19) Between the primary afflux 51 of the first heat-exchanger 30 and the port 98A, 99A to the district-heat reflux 63 a feed pump 59 is arranged. By means of the feed pump 59, the medium which is flowing in the direction of flow 65 through the district-heat reflux 63 to the district heating station 67 can flow out of the district-heat reflux 63 through the primary afflux 51 into the first heat-exchanger 30, can perfuse the latter, and furthermore flow back again through the primary reflux 53 of the first heat-exchanger 30 into the district-heat reflux 63. While the medium is perfusing the first heat-exchanger 30, heat is transferred from the primary side of the first heat-exchanger 30 to the secondary side of the first heat-exchanger 30.

(20) The district-heat consumer plant 10 comprises a port 98C via which the district-heat consumer plant 10 is linked to the district-heat afflux 61 and to the district-heat reflux 63 of the district-heat network 60, in order to withdraw heat from the district-heat afflux 61. Similarly, the district-heat afflux 61 comprises a port 99C for the district-heat consumer plant 10, in order to supply the district-heat consumer plant 10 with heat from the district-heat afflux 61.

(21) Furthermore, the district-heat consumer plant 10 comprises an afflux transfer station 43, which is of the type of a transfer station in order to withdraw heat from the district-heat afflux 61 via the afflux transfer station 43. For this purpose, the district-heat consumer plant 10 comprises a second heat-exchanger 40 with a primary afflux 52 and with a primary reflux 54, the primary afflux 52 of the second heat-exchanger 40 being linked via the afflux transfer station 43 to the district-heat afflux 61 of the district-heat network 60, and the primary reflux 54 being linked via the afflux transfer station 43 to the district-heat reflux 63, in order to withdraw heat from the district-heat afflux 61. The primary afflux 52 of the second heat-exchanger 40 is in this case linked via the port 98C of the district-heat consumer plant 10 to the port 99C of the district-heat network 60 and consequently to the district-heat afflux 61. The primary afflux 52 and the primary reflux 54 of the second heat-exchanger 40 are accordingly linked via the afflux transfer station 43 to the district-heat afflux 61 and to the district-heat reflux 63. The afflux transfer station 43 comprises shut-off valves 27A, bleed valves, manometers, a differential-pressure regulator, a calorimeter 29A and also a jet pump 24, which for reasons of representation are only shown in part in FIGS. 2 and 3 and which are interconnected as shown in FIG. 1. In this case, instead of the regulating valve 25A shown in FIG. 1 between the primary afflux 52 of the second heat-exchanger 40 and the district-heat afflux 61 there is arranged a jet pump 24 which by its working-fluid port is linked to the district-heat afflux 61 and by its suction port is linked to a primary reflux 54 of the second heat-exchanger 40. For the purpose of better and more effective transfer of heat, the first heat-exchanger 30 and the second heat-exchanger 40 are of the type of a countercurrent heat-exchanger, whereby the heat is capable of being transferred by the countercurrent principle.

(22) The primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are connected to one another and are jointly linked to the district-heat reflux 63 of the district-heat network 60. The primary reflux 54 of the second heat-exchanger 40 is accordingly connected to the primary reflux 53 of the first heat-exchanger 30 and via the port 98B of the district-heat consumer plant 10 linked to the port 99B of the district-heat network 60 and consequently to the district-heat reflux 63. In this case the reflux transfer station 33 is arranged between the common connecting node 101 of the primary reflux 53, 54 of the first heat-exchanger 30 and second heat-exchanger 40 and the first heat-exchanger 30, and the afflux transfer station 43 is arranged between the common connecting node 101 of the primary reflux 53, 54 of the first heat-exchanger 30 and second heat-exchanger 40 and the second heat-exchanger 40. The primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are accordingly connected to one another downstream of the respective calorimeters 29A, 29B. For the purpose of transfer of heat by means of the second heat-exchanger 40, a medium flows out of the district-heat afflux 61 through the afflux transfer station 43 via the primary afflux 52 of the second heat-exchanger 40, perfuses the latter and flows through the afflux transfer station 43 into the district-heat reflux 63 via the primary reflux 54 of the second heat-exchanger 40.

(23) The district-heat consumer plant 10 comprises a heat-consumer system 15 which is capable of being supplied with heat by the first heat-exchanger 30. For reasons of representation, the heat-consumer system 15 is not shown in FIG. 2. The heat-consumer system 15 is linked to the secondary side of the first heat-exchanger 30, the secondary afflux 55 of the first heat-exchanger 30 being linked to the afflux 17 of the heat-consumer system 15, and the secondary reflux 57 of the first heat-exchanger 30 being linked to the reflux 19 of the heat-consumer system 15. To the heat-consumer system 15 there are linked heat-consumers 13, in order to be supplied with heat by the first heat-exchanger 30 via the heat-consumer system 15. For this purpose, the heat-consumers 13 are connected to the afflux 17 of the heat-consumer system and to the reflux 19 of the heat-consumer system 15, whereby warm medium of the heat-consumer system 15 is delivered to the heat-consumer 13 via the afflux 17 of the heat-consumer system, said medium being cooled by the heat-consumer 13 and conducted back again into the reflux 19 of the heat-consumer system. The heat-consumer system 15 is constructed as a circuit and comprises a pump 23, in order to pump the medium of the heat-consumer system 15 through the lines of the heat-consumer system 15 from the first heat-exchanger 30 to a heat-consumer 13 and back again.

(24) To the heat-consumer system 15 there are linked four heat-consumers 13 constructed as heating circuits, in order to be supplied with heat by the first heat-exchanger 30 via the heat-consumer system 15. The heat-consumers 13 are in each instance constructed as low-temperature heating circuits for underfloor heating systems, ceiling and wall heating systems and also for heating systems of swimming-pool water, and are supplied with heat from the district-heat reflux 63 via the first heat-exchanger 30.

(25) Furthermore, the district-heat consumer plant 10 comprises a drinking-water heater 80 for the purpose of heating hot drinking water, which is capable of being supplied with heat by the first heat-exchanger 30 for the purpose of preheating the hot drinking water. For this purpose, the drinking-water heater 80 comprises a first partial drinking-water heater 81, which may also be designated as a preheater, the first partial drinking water heater 81 being capable of being supplied with heat by the first heat-exchanger 30 via the heat-consumer system 15 for the purpose of preheating the hot drinking water. For this purpose, the first partial drinking-water heater 81 is connected to the afflux 17 and to the reflux 19 of the heat-consumer system 15. The first partial drinking-water heater 81 is constructed as a heat-exchanger and arranged in a lower region of the drinking-water heater 80. By means of the first partial drinking-water heater 81 the temperature of the hot drinking water can be preheated from 10° C. up to 40° C.

(26) The second heat-exchanger 40 is connected on the secondary side to a second partial drinking-water heater 83 of the drinking-water heater 80, so that the district-heat consumer plant 10 comprises a drinking-water heater 80 for the purpose of heating hot drinking water to 60° C., which is capable of being supplied with heat by the second heat-exchanger 40 for the purpose of residual heating of the hot drinking water. For this purpose, the secondary afflux 55 of the second heat-exchanger 40 is connected to the second partial drinking-water heater 83 via a pump 23, which acts as a charge pump, and the secondary reflux 57 of the second heat-exchanger 40 is connected to the second partial drinking-water heater 83 via a check valve 95. The medium which has been heated in the second heat-exchanger flows from the secondary afflux 55 of the second heat-exchanger 40 via the pump 23 to the second partial drinking-water heater 83, perfuses the latter for the purpose of residual heating of the hot drinking water to 60° C., and subsequently flows from the second partial drinking-water heater 83 through a check valve via the secondary reflux 57 of the second heat-exchanger 40 back into the second heat-exchanger 40, in order to be heated again there. The second partial drinking-water heater 83 is constructed as a heat-exchanger and arranged in an upper region of the drinking-water heater 80.

(27) The cold drinking water to be heated is supplied to the drinking-water heater 80 via a cold-drinking-water inlet 90, is heated in the latter, and leaves the drinking-water heater as hot drinking water via the hot-drinking-water outlet 93, in order to be conducted to the consumers. In this case the cold drinking water firstly flows into the first partial drinking-water heater 81 and subsequently into the second partial drinking-water heater 83.

(28) In addition, the district-heat consumer plant 10 comprises a three-way valve 21 constructed as a mixing valve, through which the heat-consumer system 15 is capable of being supplied with heat by the second heat-exchanger 40 of the district-heat consumer plant 10. For this purpose, the three-way valve 21 is linked to the afflux 17 of the heat-consumer system, to the secondary afflux 55 of the first heat-exchanger 30 and to the secondary afflux 55 of the second heat-exchanger 40. Through the three-way valve 21 the heat-consumer system 15 can be supplied with heat on demand by the second heat-exchanger 40. Accordingly, should the medium in the heat-consumer system 15 not be heated sufficiently by the first heat-exchanger 30, medium that has been heated by the second heat-exchanger 40 can be admixed via the three-way valve 21. Via the three-way valve 21 the heat-consumer system 15 can be supplied with heat by the first heat-exchanger 30 and/or the second heat-exchanger 40. This may, for example, be an advantage in the case of an insufficient delivery of heat by the first heat-exchanger 30 by reason of a temperature of the district-heat reflux 63 that is too low, in the case of a defective first heat-exchanger 30, or in the case of peak loads. In order to enable a closed circuit of the distributor system 15, the reflux 19 of the heat-consumer system 15 is linked to the secondary reflux 57 of the second heat-exchanger via a check valve 95.

(29) The primary afflux 51 of the first heat-exchanger 30 is, as shown in FIG. 4, linked to the district-heat reflux 63 via a tubular line 71, whereby a line opening 73 of the line 71 is arranged in such a way in the district-heat reflux 63 that the line 71 with the line opening 73 is oriented contrary to a direction of flow 65 of the district-heat reflux 63. This corresponds to the line 71, which the district-heat reflux 63 comprises on the port 99A for the purpose of supplying the district-heat consumer plant 10 with heat from the district-heat reflux 63. A line opening 73 of the line 71 is arranged in such a way in the district-heat reflux 63 that the line 71 with the line opening 73 is oriented contrary to a direction of flow 65 of the district-heat reflux 63. In this case the surface spanned by the line opening 73 exhibits a normal to the surface 75, which faces away from the line 71 and is directed against the direction of flow 65, the normal to the surface 75 and the direction of flow 65 including an angle of about 45°. The line opening 73 is accordingly inclined at an angle of about 45° relative to the direction of flow 65. Such an arrangement is also designated as shoeing of the line 71 into the district-heat reflux 63. By this means, the medium being conducted in the district-heat reflux 63 is supplied to the first heat-exchanger 30 by virtue of an injector effect.

(30) Furthermore, as likewise shown in FIG. 4, the primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are linked to the district-heat reflux 63 via a tubular line, whereby a line opening 73 of the line 71 is arranged in such a way in the district-heat reflux 63 that the line 71 with the line opening 73 is oriented in a direction of flow 65 of the district-heat reflux 63. This line corresponds to the line 71, which is arranged on a port 99B of the district-heat reflux 63 via which the medium cooled by the first heat-exchanger 30 and/or second heat-exchanger 40 can again be routed into the district-heat reflux. The district-heat reflux 63 accordingly comprises a port 99B with a line 71 for a district-heat consumer plant 10, in order to route medium cooled by the district-heat consumer plant 10 into the district-heat reflux 63, whereby a line opening 73 of the line 71 is arranged in such a way in the district-heat reflux 63 that the line 71 with the line opening 73 is oriented in a direction of flow 65 of the district-heat reflux 63. In this case the surface spanned by the line opening 73 exhibits a normal to the surface 75, which faces away from the line 71 and is directed in the direction of flow 65, the normal to the surface 75 and the direction of flow 65 including an angle of about 45°. Such an arrangement of the line 71 on the district-heat reflux 63 is ordinarily designated as shoeing. In this case, according to Bernoulli's law a drop in dynamic pressure may arise by virtue of the medium flowing past the line opening 73, which has the effect that the medium located in the line 71 flows out of the line 71 into the district-heat reflux 63. In FIG. 4 the throttle valve 20 is not shown, for reasons of representation.

(31) In a second exemplary embodiment, represented in FIG. 5, which otherwise does not differ from the first exemplary embodiment, the feed pump 59 is arranged between the primary reflux 53 of the first heat-exchanger 30 and the district-heat reflux 63. By this means, the suction effect of the feed pump 59 is improved, resulting in an improvement of the transfer of heat of the first heat-exchanger 30. This is an advantage, above all, in the case of high pressures and/or high flow velocities within the district-heat reflux 63.

(32) In a third exemplary embodiment, represented in FIGS. 6 and 7, which otherwise does not differ from the first exemplary embodiment, the primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are linked to the district-heat reflux 63 of the district-heat network 60 separately from one another. The primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are accordingly linked, separately from one another, via a port 98B of the district-heat consumer plant 10 to a port 99B of the district-heat network 60, and consequently to the district-heat reflux 63. The first heat-exchanger 30 and the second heat-exchanger 40 accordingly comprise a primary reflux 53, which are not at first connected to one another, in order subsequently to be linked to the district-heat reflux 63, but are linked to the district-heat reflux 63 via separate lines. In the case of the district-heat consumer plant 10 represented in FIGS. 6 and 7 it is accordingly a question of a four-conductor system, since the district-heat consumer plant 10 comprises four ports to the district-heat network 60. These are the primary afflux 51 of the first heat-exchanger 30, the primary afflux 52 of the second heat-exchanger 40, and also the primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40. In this case the primary afflux 51 of the first heat-exchanger 30 and also the primary reflux 53 of the first heat-exchanger 30 and the primary reflux 54 of the second heat-exchanger 40 are linked to the district-heat reflux 63 via tubular lines 71, as represented in FIG. 4.

(33) In a fourth exemplary embodiment, represented in FIG. 8, which otherwise does not differ from the third exemplary embodiment, the feed pump 59 is arranged between the primary reflux 53 of the first heat-exchanger 30 and the district-heat reflux 63. By this means, as already elucidated for the second exemplary embodiment, the suction effect of the feed pump 59 is improved, resulting in an improvement of the transfer of heat of the first heat-exchanger 30. This is an advantage, above all, in the case of high pressures and/or high flow velocities within the district-heat reflux 63.

(34) The features disclosed in the above description, in the claims and in the drawings may be of significance, both individually and in arbitrary combination, for the realisation of the patent application in its various embodiments.

LIST OF REFERENCE SYMBOLS

(35) 1 district-heat system

(36) 10 district-heat consumer plant

(37) 13 heat-consumer

(38) 15 heat-consumer system

(39) 17 afflux of the heat-consumer system

(40) 19 reflux of the heat-consumer system

(41) 21 throttle valve

(42) 21 three-way valve

(43) 22A differential-pressure regulator of the afflux transfer station

(44) 23 pump

(45) 24 jet pump

(46) 25A regulating valve of the afflux transfer station

(47) 26A bleed valve of the afflux transfer station

(48) 27A shut-off valve of the afflux transfer station

(49) 27B shut-off valve of the reflux transfer station

(50) 28A manometer of the afflux transfer station

(51) 29A calorimeter of the afflux transfer station

(52) 29B calorimeter of the reflux transfer station

(53) 30 first heat-exchanger

(54) 33 reflux transfer station

(55) 40 second heat-exchanger

(56) 43 afflux transfer station

(57) 51 primary afflux of the first heat-exchanger

(58) 52 primary afflux of the second heat-exchanger

(59) 53 primary reflux of the first heat-exchanger

(60) 54 primary reflux of the second heat-exchanger

(61) 55 secondary afflux

(62) 57 secondary reflux

(63) 59 feed pump

(64) 60 district-heat network

(65) 61 district-heat afflux

(66) 63 district-heat reflux

(67) 65 direction of flow

(68) 67 district heating station

(69) 69 district-heat pump

(70) 71 line

(71) 73 line opening

(72) 75 normal to the surface

(73) 80 drinking-water heater

(74) 81 first partial drinking-water heater

(75) 83 second partial drinking-water heater

(76) 90 cold-drinking-water inlet

(77) 93 hot-drinking-water outlet

(78) 95 check valve

(79) 98A port of the district-heat consumer plant

(80) 98B port of the district-heat consumer plant

(81) 98C port of the district-heat consumer plant

(82) 99A port of the district-heat reflux

(83) 99B port of the district-heat reflux

(84) 99C port of the district-heat afflux

(85) 101 connecting node