Heating device and heating method

Abstract

According to the invention, a heating device is provided comprising a water storage tank (1), a first heat exchanger (2) configured to transfer heat from a heating fluid to water arranged in the water storage tank (1), a supply line (3) configured to supply heating fluid to the first heat exchanger (2), a return line (4) configured to carry heating fluid away from the first heat exchanger (2), a cold water line (5) configured to supply water to the water storage tank (1), and a hot water line (6) configured to carry water away from the water storage tank (1), wherein a second heat exchanger (7) and a branch line (8) connecting the supply line (3) to the return line (4) are provided, the second heat exchanger (7) being configured to transfer heat from a heating fluid carried in the branch line (8) to a water line (5) connected to the water storage tank.6) to transfer guided water.

Description

[0001] The invention relates to a heating device comprising a water storage tank, a first heat exchanger configured to transfer heat from a heating fluid to water arranged in the water storage tank, a supply line configured to supply a heating fluid to the first heat exchanger, a return line configured to carry heating fluid away from the first heat exchanger, a cold water line configured to supply water to the water storage tank, and a hot water line configured to carry water away from the water storage tank.

[0002] The invention further relates to a heating method in which a heating fluid is supplied to a first heat exchanger via a supply line, thereby heating water in a water storage tank, and the heating fluid is carried away from the first heat exchanger via a return line, wherein water is optionally supplied to the water storage tank via a cold water line and water is optionally carried away from the water storage tank via a hot water line.

[0003] Various devices and methods for heating, particularly water in a storage tank, such as a boiler, are known in the prior art. In these systems, water in a storage tank is heated by means of a heat exchanger supplied via a flow line with a heating fluid at a temperature above the target temperature until the desired temperature is reached. The heating fluid is then returned to the heat exchanger via a return line. The heated water in the storage tank can then be drawn off via a hot water pipe. To refill the storage tank and replace the water drawn, it is also connected to a cold water pipe, through which (cold) water is supplied as needed. As soon as the temperature in the storage tank falls below a predefined level, e.g.,When hot water is drawn and the tank is refilled with cold water, the water in the storage tank is reheated using the heat exchanger.

[0004] Such a heating device is known from EP 0332606 A2. Additionally, a second heat exchanger is provided, designed to transfer heat from the heating fluid in the return line to the cold water in the cold water line. This allows the cold water to be warmed slightly before it enters the water storage tank, thus reducing the cooling effect on the water in the storage tank and lowering the heat requirement to achieve or maintain the desired temperature.

[0005] From AT 285114 B, a water storage tank is known whose supply line runs through several radiators. A circuit enables heating fluid from the supply line to be fed directly to a heat exchanger located in the water storage tank if the tank requires heat.

[0006] From EP 4141334 A1, a method for operating a heating system is known in which heating water is heated in a combustion chamber and then supplied to a heating circuit comprising several radiators. Furthermore, a branch line is provided from the flow line of the heating circuit to the return line of the heating circuit, which includes a heat exchanger so that cold domestic hot water can be passed through this heat exchanger to be heated. A hot water storage tank is not provided in this method.

[0007] A particular disadvantage of the known solutions is the inertia of the heating system after a certain amount of hot water has been drawn. Due to the temperature-dependent control of the heating fluid supply, a relatively long time is required to bring the temperature in the water storage tank or of the water dispensed through the hot water pipes back up to the desired temperature after a significant draw-off, because the reaction time until the heating fluid supply begins is relatively long. Consequently, in certain situations, especially with larger draw-offs, the temperature of the dispensed hot water may not reach the desired temperature due to the delayed reheating.

[0008] It is therefore an object of the invention to provide a device and a method that make it possible to maintain the temperature of the hot water supplied through the hot water line at the desired temperature even after large amounts of hot water have been drawn off. Preferably, a device or method should be provided that allows for greater flexibility in the heating process.

[0009] According to the invention, a device of the type mentioned above is provided, in which a second heat exchanger and a branch line connecting the supply line to the return line are provided. The second heat exchanger is designed to transfer heat from a heating fluid flowing in the branch line to water flowing in a water line connected to the water storage tank. The branch line (bypass line) is designed to carry heating fluid from the supply line to the return line without the heating fluid flowing through the branch line entering the first heat exchanger. The branch line is therefore arranged parallel to the first heat exchanger and runs through the second heat exchanger. Heating fluid can be used with the aid of the branch line, for example, to heat water flowing from the water storage tank through the hot water line and / or cold water in the cold water line outside the water storage tank.This significantly increases the flexibility of the heating system and allows the water supplied through the hot water line to be heated to the desired temperature using the second heat exchanger, even if the temperature in the water storage tank is lower, i.e., below the desired temperature, for example, due to increased water consumption. Alternatively, it allows the cold water supplied to the water storage tank to be preheated, thus minimizing the drop in water temperature when cold water is added. Combinations or other uses of the second heat exchanger are also possible.

[0010] The cold water line and the hot water line are both water pipes connected to the water storage tank. Preferably, the cold water line has an inlet in the lower part of the water storage tank to supply water. The hot water line is designed to draw water from the water storage tank and preferably has an outlet in the upper part of the tank, allowing water to be drawn from the tank through the outlet.

[0011] Preferably, the second heat exchanger is designed to transfer heat from a heating fluid carried in the branch line to water carried in the hot water line or in the cold water line.

[0012] Preferably, the branch line has a branch valve to control the flow through it. Particularly preferably, the branch valve is designed to be controlled based on measurements obtained by a differential pressure regulator. The differential pressure regulator is designed to determine the differential pressure of the water in the cold water line between the first water pressure measured at a first measuring point and the second water pressure measured at a second measuring point located downstream of the first measuring point. Thus, the differential pressure regulator determines the differential pressure of the water in the cold water line between two spaced-apart points along the cold water line, the measuring points. This arrangement significantly improves the response time of the heating device, especially to larger water withdrawals, compared to purely temperature-based measuring systems.The flow rate of the heating fluid through the branch line and the second heat exchanger is regulated based on the pressure differential in the cold water line, which changes much faster than, for example, the temperature in the water storage tank. Therefore, if a larger amount of hot water is drawn and thus flows through the cold water line, the branch valve is actuated and opened promptly due to the pressure differential in the cold water line. The branch valve is, for example, a three-way valve. Furthermore, the branch valve is preferably located downstream of the second heat exchanger.

[0013] To prevent unwanted backflow through the cold water pipe towards the water storage tank, it is preferably provided that a check valve is arranged in the cold water pipe between the first measuring point and the second measuring point.

[0014] It is further preferred that a pressure reducer be installed in the cold water line upstream of the first measuring point. This arrangement allows the pressure, supplied, for example, by a domestic water connection, to be reduced to a pressure required for the heating device.

[0015] Furthermore, it is preferably provided that a safety valve (pressure relief valve) is arranged in the cold water line between the first and second measuring points. This safety valve is designed to prevent excessive pressure in the cold water line and, if necessary, to reduce the pressure by removing water from the cold water line. The safety valve can, for example, be set to a maximum pressure of seven bar.

[0016] To allow for the mixing of water from the cold water line with the water flowing in the hot water line, the cold water line and the hot water line are preferably connected via a mixing line. The mixing line is preferably a branch line of the cold water line, designed to supply water from the cold water line to the hot water line. Preferably, the hot water line is connected to the mixing line by means of a mixing valve. The mixing valve is, for example, a thermostatic mixing valve, preferably designed as a three-way valve. The thermostatic mixing valve has, for example, an inlet for the hot water line, an inlet for the mixing line or the cold water line, and an outlet for the hot water line. If required, for example, when a preset temperature (e.g.,If the temperature exceeds 51°C, cold water can be mixed with the hot water in the hot water pipe using the mixing valve to achieve a desired temperature in the hot water pipe and thus of the water dispensed through the hot water pipe.

[0017] It is particularly preferred that the differential pressure regulator is connected to the first measuring point via a first measuring line and to the second measuring point via a second measuring line. The water pressure at the first measuring point is transmitted to the differential pressure regulator via the first measuring line, and the water pressure at the second measuring point is transmitted to the differential pressure regulator via the second measuring line. The measuring lines are preferably capillary lines. The differential pressure is then determined in the differential pressure regulator, and the branch valve is controlled based on this measurement. This allows for a branch valve to be designed without auxiliary power.

[0018] The amount of fluid flowing through the branch line and the second heat exchanger, or through the first heat exchanger, can be adjusted as needed by suitably positioned valves. Preferably, the return line between the first heat exchanger and the connection point to the branch line located downstream of the first heat exchanger includes a storage valve connected to a temperature sensor. The storage valve is designed to be controlled based on the measured values ​​determined by the temperature sensor. Therefore, it is preferred that the branch line is connected to the return line downstream of a storage valve located in the return line. The temperature sensor is preferably designed to determine the temperature of the water in the water storage tank.Based on the measured water temperature, the storage valve can be controlled accordingly to adjust the flow rate of the heating fluid. Since more or less heating fluid flows through the branch line depending on the position of the storage valve, this also regulates the flow rate through the branch line and thus through the second heat exchanger. The storage valve is, for example, a flow limiting valve.

[0019] Furthermore, it is preferably stipulated that the second heat exchanger is a plate heat exchanger. Plate heat exchangers have a high efficiency and are versatile, making them well-suited for this application. Alternatively or additionally, the second heat exchanger can also have a different design; for example, the pipes can share a common boundary or be positioned so close together that heat transfer is possible.

[0020] The first heat exchanger is located, for example, inside the water storage tank and is preferably surrounded by water during operation. The first heat exchanger transfers heat from the heating fluid within it to the water in the storage tank. For this purpose, the first heat exchanger is connected to the flow and return lines. The first heat exchanger comprises, or is itself, for example, a heating coil.

[0021] Furthermore, it is preferably provided that the branch line is connected downstream to a first inlet of a three-way valve and the return line is connected to a second inlet of the three-way valve. The branch line and the return line are connected to each other by means of a three-way valve, allowing heating fluid from the branch line to flow into the return line. The three-way valve is particularly preferably designed as a branch valve and is further preferably configured to be controlled by the differential pressure in the cold water line. This has the advantage that the ratio of the amount of heating fluid flowing through the return line and the branch line can be easily controlled. The return line is routed through an inlet of the three-way valve and out of the outlet of the three-way valve. Heating fluid from the branch line can be fed into the return line within the three-way valve.

[0022] Alternatively, the branch line is directly connected to the return line. In this case, the branch valve is located upstream of where the branch line connects to the return line. The branch valve is designed as a two-way valve, preferably with reverse action.

[0023] The respective pipes and valves for guiding the water or heating medium are each designed accordingly and therefore have the corresponding structures and dimensions.

[0024] The water storage tank preferably has insulation to prevent or reduce the cooling of the water within the tank through exchange with the surrounding air. The water storage tank is, for example, designed as a boiler.

[0025] The valves and sensors are preferably purely mechanical in design and do not require any auxiliary energy such as a power supply during operation. In this design, the energy required for measuring, opening, and closing the valves is supplied by the water or heating fluid in the system. This enables autonomous operation and greater flexibility during installation and operation of the device.

[0026] The heating fluid supplied to the first heat exchanger via the flow pipe can be heated, for example, by a gas boiler, a heat pump, or district heating. The heating fluid carried away via the return pipe is preferably reheated and used again via the flow pipe to heat the water in the storage tank.

[0027] Furthermore, according to the invention, a heating method of the type mentioned at the outset is provided, wherein heating fluid is optionally guided via a branch line from the supply line to the return line via a second heat exchanger, wherein in the second heat exchanger heat is transferred from the heating fluid carried in the branch line to water carried in a water line connected to the water storage tank.

[0028] Preferably, heat is transferred in the second heat exchanger from the heating fluid carried in the branch line to water carried in the hot water line and / or in the cold water line.

[0029] Furthermore, it is preferably provided that a branch valve arranged in the branch line is controlled based on measured values ​​determined by a differential pressure regulator, wherein the differential pressure regulator determines the differential pressure of the water flowing in the cold water line between the first water pressure measured at a first measuring point and the second water pressure measured at a second measuring point arranged downstream of the first measuring point. The branch valve is preferably arranged downstream of the second heat exchanger.

[0030] The invention is explained in more detail below with reference to an exemplary embodiment schematically illustrated in the drawing. This shows Fig. 1 a first heating device according to the invention, Fig. 2 a second heating device according to the invention and Fig. 3 a third heating device according to the invention.

[0031] In Fig. 1 Figure 1 shows a first embodiment of a heating device according to the invention. The arrows indicate the respective flow direction within the pipes during operation. The heating device comprises a water storage tank 1, a first heat exchanger 2 configured to heat water arranged in the water storage tank 1, a supply line 3 configured to supply a heating fluid to the first heat exchanger 2, a return line 4 configured to carry heating fluid away from the first heat exchanger 2, a cold water line 5 connected to the water storage tank 1 and configured to supply water to the water storage tank 1, and a hot water line 6 connected to the water storage tank 1 and configured to carry water away from the water storage tank 1.Furthermore, a second heat exchanger 7 is provided, which is part of the hot water line 6 on one side and part of a branch line 8 that connects the supply line 3 with the return line 4 on the other. This allows the second heat exchanger 7 to be supplied with water in the hot water line 6 and heating fluid in the branch line 8 during operation, so that heat is transferred from the heating fluid in the branch line 8 to the water in the hot water line 6. In this design, the branch line 8 is connected to the return line 4 by means of a three-way valve 9 and to the supply line 3 by means of a simple branch connection. The branch valve 9 has, in addition to the inlet of the branch line 8, an inlet for the return line 4 coming from the first heat exchanger 2 and the return line 4 as its outlet.The branch valve 9 is connected to a differential pressure regulator 10, so that the position of the branch valve 9 can be controlled based on the differential pressure measured in the differential pressure regulator 10. The differential pressure regulator 10 has a first measuring point 11 and a second measuring point 12, both of which are located in the cold water line 5. The second measuring point 11 is located downstream of the first measuring point 12. Using the differential pressure regulator 10, the pressure difference of the water flowing in the cold water line 5 between the first measuring point 11 and the second measuring point 12 can be measured, and the branch valve 9 can be controlled or regulated accordingly. The first measuring point 11 is connected to the differential pressure regulator 10 via a first measuring line 13, and the second measuring point 12 is connected to the differential pressure regulator 10 via a second measuring line 14. The measuring lines 13 and 14 are shown with dashed lines and are, for example,The cold water line 5 is designed as capillary tubes. It also has a check valve 15 located downstream of the first measuring point 11. To allow water from the cold water line 5 to be mixed with the water in the hot water line 6, the cold water line 5 and the hot water line 6 are connected by means of a thermostatic mixing valve 16 and a mixing line 19. Additionally, the cold water line 5 has a pressure reducer 17 upstream of the first measuring point 11, which allows the pressure in the cold water line 5 to be reduced to a desired pressure if necessary. A safety valve (not shown) can be located between the first measuring point 11 and the second measuring point 12 to prevent damage from excessive pressure.Furthermore, the return line 4 downstream of the first heat exchanger 2 has a flow limiting valve 18, which is connected to a thermostatic head designed to determine the temperature in the water storage tank 1. The flow limiting valve 18 can be controlled or regulated based on the temperature measured in the water storage tank 1.

[0032] During operation, water is supplied to the water storage tank 1 via the cold water line 5 (in the direction of the arrow) in the lower section until the water storage tank 1 is full. The water in the water storage tank 1 is heated by the heating fluid supplied via the flow line 3 (in the direction of the arrow) using the first heat exchanger 2 until the desired temperature is reached and the flow limiting valve 18 closes, so that no heating fluid is passed through the flow line 3 and the return line 4 via the first heat exchanger 2. If required, hot water is drawn from the water storage tank 1 via the hot water line 6 (in the direction of the arrow), for example using a tap (not shown), and the water storage tank 1 is refilled via the cold water line 5.The differential pressure regulator 10 measures the volume of water being added and, if necessary, especially when a large quantity of water is added, controls the branch valve 9 so that heating fluid flows through the branch line 8 and the second heat exchanger 7. The heating fluid can flow through both the first heat exchanger 2 and the second heat exchanger 7, or only through the second heat exchanger 7. This additionally heats the water drawn from the hot water storage tank 1 via the hot water line 6 to bring it to the desired temperature. By heating the water in the hot water line 6 via the second heat exchanger 7, hot water can be supplied through the hot water line 6 even if the temperature in the hot water storage tank 1 is lower.After the withdrawal, the differential pressure regulator 10 detects the end of the refilling through the cold water line 5 and the branch valve 9 is activated, so that the entire heating fluid is again routed through the first heat exchanger 2 to heat the water in the water storage tank 1.

[0033] In Fig. 2 A second embodiment of a heating device according to the invention is shown. This embodiment differs from the embodiment according to Fig. 1 This is achieved by the fact that the branch valve 9 is not designed as a three-way valve, but as a two-way valve, which is arranged in the branch line 8 before the branch line 8 connects to the return line 4. In this design, the flow through the branch line 8 is regulated by means of the differential pressure regulator 10 and the branch valve 9.

[0034] In Fig. 3 A third embodiment of a heating device according to the invention is shown. This embodiment differs from the embodiment according to Fig. 1 This is achieved by routing the cold water line 5 through the second heat exchanger 7, rather than the hot water line 6. In this configuration, the hot water to be discharged through the hot water line 6 is not reheated; instead, the water in the cold water line 5 is heated before being introduced into the water storage tank 1, thus reducing the cooling effect of the newly introduced water in the water storage tank 1.

Claims

1. Heating device comprising a water storage tank (1), a first heat exchanger (2) configured to transfer heat from a heating fluid to water arranged in the water storage tank (1), a supply line (3) configured to supply heating fluid to the first heat exchanger (2), a return line (4) configured to carry heating fluid away from the first heat exchanger (2), a cold water line (5) configured to supply water to the water storage tank (1), and a hot water line (6) configured to carry water away from the water storage tank (1). characterized by the fact that a second heat exchanger (7) and a branch line (8) connecting the supply line (3) to the return line (4) are provided, wherein the second heat exchanger (7) is designed to transfer heat from a heating fluid carried in the branch line (8) to water carried in a water line (5,6) connected to the water storage tank.

2. Heating device according to claim 1, characterized by the fact that the second heat exchanger (7) is designed to transfer heat from a heating fluid carried in the branch line (8) to water carried in the hot water line (6) or in the cold water line (5).

3. Heating device according to claim 1 or 2, characterized by the fact that the branch line (8) has a branch valve (9) to control the flow through the branch line (8).

4. Heating device according to claim 3, characterized by the fact that the branch valve (9) is designed to be controlled based on measured values ​​determined by a differential pressure regulator (10), wherein the differential pressure regulator (10) is designed to determine the differential pressure of the water carried in the cold water line (5) between the first water pressure measured at a first measuring point (11) and the second water pressure measured at a second measuring point (12) arranged downstream of the first measuring point (11).

5. Heating device according to claim 4, characterized by the fact that the differential pressure regulator (10) is connected to the first measuring point (11) via a first measuring line (13) and to the second measuring point (12) via a second measuring line (14).

6. Heating device according to claim 4 or 5, characterized by the fact that A check valve (15) is arranged in the cold water line (5) between the first measuring point (11) and the second measuring point (12).

7. Heating device according to one of claims 4 to 6, characterized by the fact that a pressure reducer (17) is arranged upstream of the first measuring point (11) in the cold water line (5).

8. Heating device according to one of claims 4 to 7, characterized by the fact that A safety valve is arranged in the cold water line (5) between the first measuring point (11) and the second measuring point (12).

9. Heating device according to one of claims 1 to 8, characterized by the fact thatthe cold water pipe (5) and the hot water pipe (6) are connected to each other via a mixing pipe (19).

10. Heating device according to one of claims 1 to 9, characterized by the fact that the branch line (8) downstream of a storage valve (9) is connected to the return line (4).

11. Heating device according to one of claims 1 to 10, characterized by the fact that the second heat exchanger (7) is a plate heat exchanger.

12. Heating device according to one of claims 1 to 11, characterized by the fact that the branch line (8) is connected downstream to a first inlet of a three-way valve and the return line (4) is connected to a second inlet of the three-way valve.

13. Heating method in which a heating fluid is supplied to a first heat exchanger (2) via a supply line (3), thereby heating water in a water storage tank (1), and the heating fluid is carried away from the first heat exchanger (2) via a return line (4), wherein water is optionally supplied to the water storage tank (1) via a cold water line (5) and water is optionally carried away from the water storage tank (1) via a hot water line (6), characterized by the fact that Optionally, heating fluid is routed via a branch line (8) from the supply line (3) to the return line (4) via a second heat exchanger (7), whereby in the second heat exchanger (7) heat is transferred from the heating fluid routed in the branch line (8) to water routed in a water line (5,6) connected to the water storage tank.

14. Heating method according to claim 13, characterized by the fact thatIn the second heat exchanger (7), heat is transferred from the heating fluid carried in the branch line (8) to water carried in the hot water line (6) and / or in the cold water line (5).

15. Heating method according to claim 13 or 14, characterized by the fact that A branch valve (9) arranged in the branch line (8) is controlled based on measured values ​​determined by a differential pressure regulator (10), wherein the differential pressure regulator (10) determines the differential pressure of the water carried in the cold water line (5) between the first water pressure measured at a first measuring point (11) and the second water pressure measured at a second measuring point (12) arranged downstream of the first measuring point (11).

Images