Heating device, method for operating a heating device

Abstract

A heating appliance (12) is proposed, comprising a hot water preparation system and including at least: a heat exchanger (3) configured to transfer a heat flow from a heating circuit (13) to a water flow for hot water preparation, and a storage tank (9) arranged between the heat exchanger (3) and a hot water outlet (8), wherein a controllable hot water bypass valve (4) is arranged and configured such that hot water can be directed from the heat exchanger (3) directly to the hot water outlet (8). A method for operating the heating appliance (12) is also proposed, comprising at least the following steps: a) closing the hot water bypass valve (4) so ​​that when hot water is drawn from the hot water outlet (8), the hot water is drawn from the storage tank (9), and b) opening the hot water bypass valve (4) when the hot water flowing from the heat exchanger (3) has reached a desired temperature.The process and heating unit enable a particularly convenient hot water supply.

Description

[0001] The invention relates to a heater, a method for operating a heater and a control device of a heater.

[0002] To provide hot water, a heating device often has a heat exchanger that can transfer a heat flow to a mass flow of drinking or domestic water that needs to be heated. The disadvantage of this is that the water temperature is often too low at the beginning of hot water use until a sufficient heat flow has been established in the heat exchanger. Furthermore, excessive temperatures can occur if the hot water outlet is reopened shortly after it has been closed.

[0003] For example, DE 10 2005 036 882 A1 proposes a hot water preparation system that uses a control valve with very fast control times, thus eliminating the need for a hot water tank. However, the system cannot prevent undesirable temperature fluctuations at the beginning of hot water use.

[0004] In this environment, storage tanks are sometimes used in which water heated to the desired temperature is stored and which are arranged between the heat exchanger and the hot water outlet. So-called micro tanks, which can store a small amount of water, can be used for this purpose, especially in smaller, for example wall-mounted, heaters. To prevent the hot water contained in the micro tanks from cooling down, an additional electric heater can be provided, designed to heat the water in the micro storage tank. In particular, when only small amounts of hot water are frequently drawn and the user does not generally expect water at the desired temperature, the additional electric heater must be switched on very regularly. The disadvantage is the high energy costs associated with switching on the additional heater. In addition, an additional heater increases the complexity of the heater and requires additional installation space.

[0005] GB 2503781A describes a hybrid heat pump-boiler system in which hot water from a storage tank, which can be heated by the boiler and / or a heat pump, can be fed directly to a hot water outlet or additionally heated via a three-way valve via a heat exchanger in the boiler. However, the proposed hybrid heat pump-boiler system is complex and, moreover, not practical for use with a micro tank, thus requiring considerable installation space.

[0006] EP 0 675 326 A1 discloses a water heating system for preparing drinking or service water. Drinking or service water can be heated from a cold water inlet through a heat exchanger located in a heat storage tank containing heating water. It can then be fed to a heat exchanger connected to a heating circuit before being supplied to a hot water outlet. Using a three-way valve, the hot water can also be fed directly to the heat exchanger, bypassing the heat storage tank. This solution also requires considerable installation space and can lead to undesirable fluctuations in the hot water temperature at the beginning of a draw.

[0007] US 2010 / 0257882 A1 describes a hybrid hot water system comprising a first hot water tank, which can be heated by the cooling circuit of a sustainable heat generation system, and a second hot water tank, which can be heated by a conventional heat generator, such as an electric heating element or a gas boiler. A bypass system allows for bypassing the first water tank and thus directly drawing hot water from the second hot water tank. This hot water system also requires considerable space and has a complex structure.

[0008] US 2010 / 0031953 A1 describes a further development of the hot water system described in US 2010 / 0257882 A1 with the same disadvantages mentioned above.

[0009] Based on this, the object of the invention is to propose a heating device and a method for operating a heating device that at least partially overcome the described problems of the prior art. In particular, a convenient and energy-efficient hot water supply is to be enabled.

[0010] In addition, the invention should at least not significantly increase the complexity of a heater and require only minor structural changes to a heater and enable easy integration into an existing production process.

[0011] These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It should be noted that the features listed in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features specified in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0012] A heating device having a hot water preparation system with at least the following elements contributes to this: a heat exchanger connected to a water inlet, designed to transfer a heat flow from a heating circuit to a water flow for hot water preparation, and a storage tank arranged between the heat exchanger and a hot water outlet for receiving drinking or service water, wherein a controllable hot water bypass valve is arranged between a withdrawal line and a supply line of the storage tank and is arranged so that, in an open position of the hot water bypass valve, hot water can be directed from the heat exchanger past the storage tank directly to the hot water outlet.

[0013] The heater comprises at least one heat generator, in particular a gas condensing boiler, which releases thermal energy through the combustion of a fuel and can transfer it to a heating circuit via at least one heat exchanger, wherein consumers of the heating circuit can be connected to the heater via a heating flow and a heating return. The exhaust gases produced during combustion can be fed to an exhaust system via an exhaust duct of the heater. In the heater, a circulating pump in the heating circuit can be configured to circulate a heat transfer medium (heating water), wherein heat transfer medium heated via a heating flow can be fed to consumers, such as convectors or surface heating systems, and returned to the heat generator or the at least one heat exchanger via a heating return.

[0014] To provide hot water, the heater can have a water inlet and a hot water outlet for drawing off the heated drinking or domestic water.

[0015] The storage tank can be any state-of-the-art storage container. In particular, the storage tank can be a stratified storage tank, which, by creating a (vertical or geodetic) temperature stratification of the drinking or service water contained within it, allows water to be supplied and withdrawn at different temperatures depending on the withdrawal height in the stratified storage tank. The storage tank can also have a thermally insulating casing to reduce heat loss to the environment.

[0016] The controllable hot water bypass valve can be set to an open position (allowing water to flow through it) and a closed position (preventing water flow). In the open position, hot water from the heat exchanger can flow past the storage tank directly into the hot water outlet. In particular, in the open position, a small portion of the water can also flow into or through the stratified storage tank, thus maintaining a constant temperature there. This position is particularly suitable when the water flowing out of the heat exchanger has reached the desired temperature.

[0017] According to an advantageous embodiment, the storage tank can be a so-called micro-storage tank. These micro-storage tanks can have a maximum capacity of 10 liters, often in the range of approximately 3 liters. Temperature stratification can develop within a micro-storage tank (for example, if it has a very slim shape), so it can also be considered a stratified storage tank.

[0018] According to an advantageous embodiment, the heat exchanger for transferring a heat flow from the heating circuit to a water flow for hot water preparation can be a plate heat exchanger. A plate heat exchanger enables particularly high heat transfer performance.

[0019] According to an advantageous embodiment, a supply line for heated water from the heat exchanger of the hot water preparation system to the storage tank can terminate in a lower cold zone of the storage tank. The cold zone has a temperature range of 5 to 45 °C [degrees Celsius]. Alternatively, the cold zone can encompass the lowest temperatures in the storage tank.

[0020] According to a further advantageous embodiment, a withdrawal line can lead from an upper hot area of ​​the storage tank to the water outlet. The hot area, in particular, has a temperature range of 45 to 65 °C [degrees Celsius]. Alternatively, the hot area can encompass the highest temperatures in the storage tank.

[0021] The hot water bypass valve is located in a bypass line between the extraction line and the supply line, or, depending on the structural conditions of the heater, the supply and extraction lines are directly connected.

[0022] According to an advantageous embodiment, a flow measuring device can be arranged in an area between a water inlet and the heat exchanger and / or between the heat exchanger (3) and the hot water bypass valve. The flow measuring device can detect the withdrawal of hot water from the hot water outlet and incorporate this into the control of the hot water bypass valve.

[0023] According to an advantageous embodiment, a temperature sensor can be arranged such that the temperature of the water at the outlet of the heat exchanger can be measured in a supply line to the storage tank. The temperature sensor enables the temperature of the heated water to be detected and thus compared with a desired (target) temperature.

[0024] According to a further aspect, a method for operating a heating device proposed here is also provided, comprising at least the following steps: a) Closing the hot water bypass valve so that when hot water is drawn from the hot water outlet, the hot water is drawn from the storage tank, b) Opening the hot water bypass valve when the hot water flowing out of the heat exchanger has reached the desired temperature.

[0025] Steps a) and b) can be performed depending on the specified operating conditions of the heater. Step a) can be performed by closing or keeping the hot water bypass valve closed if no water is drawn from the hot water outlet, or if water is drawn but the temperature of the hot water flowing out of the heat exchanger does not correspond to the desired temperature.

[0026] The hot water bypass valve can be closed as described in step a) if the temperature of the water flowing out of the heat exchanger is too low or too high. The closed hot water bypass valve supplies hot water of the desired temperature from the storage tank to the hot water outlet.

[0027] According to step b), the hot water bypass valve can be opened when water of the desired temperature emerges from the heat exchanger. Opening the hot water bypass valve allows water emerging from the heat exchanger to flow directly to the hot water outlet, making it possible to draw large amounts of hot water, for example, to fill a bathtub.

[0028] According to a further aspect, a computer program is also proposed, which is configured to carry out a method proposed here. In other words, this relates to a computer program product comprising instructions which, when the program is executed by a computer (such as a control unit), cause the computer to carry out a method described here.

[0029] According to a further aspect, a storage medium on which the computer program is stored is also proposed. The storage medium is usually a computer-readable storage medium.

[0030] According to a further aspect, a control unit for a heater is also proposed, configured to carry out a method proposed here. For this purpose, the control unit can, for example, comprise or have a processor that can execute the method or computer program stored, for example, in a memory of the control unit.

[0031] According to a further aspect, a heating device described here is also proposed, comprising a control device proposed here.

[0032] By using a hot water bypass valve, positioned between a heat exchanger and a storage tank of a heating device, the comfort of hot water preparation can be increased. This increase in comfort can, in particular, consist of hot water preparation that maintains the desired temperature from the very beginning of hot water use and also ensures a large drawoff volume.

[0033] Thus, a heating device, a method for operating the same, a computer program, and a control device are provided here, which at least partially solve the problems described with reference to the prior art. In particular, the invention at least contributes to enabling a high level of convenience in hot water provision; in particular, it can be ensured that hot water can be drawn off at a desired temperature at virtually any time. Furthermore, the invention can enable particularly high energy efficiency in hot water provision.

[0034] Last but not least, the invention can be very easily implemented in a heating device, requiring hardly any additional components and thus only minimal additional installation space. In fact, a conventional auxiliary electric heater for the storage tank can even be omitted. This also advantageously allows for a very cost-effective implementation of the invention.

[0035] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and, in particular, the proportions shown are only schematic. It shows: Fig. 1: a heater proposed here.

[0036] Fig. 1 shows, by way of example and schematically, a heating device 12 proposed here. This can comprise a heat generator 1, which can transfer a heat flow to a heating circuit 13. The heat generator 1 can, for example, be a gas condensing boiler, and the heat flow generated by the combustion of a fuel can be transferred to the heating circuit 13 via a heat exchanger. A circulation pump can be arranged in the heating circuit 13, which circulates a heat transfer medium (heating water).

[0037] A heat exchanger 3 can be arranged between a heating flow 6 and a heating return 5 of the heating circuit 13 such that the heat transfer medium of the heating circuit 13 can flow through it. The heat exchanger 3 can also be connected to a water inlet 7 and transfer a heat flow from the heat transfer medium in the heating circuit 13 to a water flow from the water inlet 7.

[0038] Downstream of the heat exchanger 3, there may be a storage tank 9, which may be designed, in particular, as a stratified storage tank with an upper hot section and a lower cold section. A supply line 17 from the outlet of the heat exchanger 3, from which heated water from the water inlet 7 emerges, may open into the cold section of the storage tank 9. A withdrawal line 15 may connect the upper hot section of the storage tank (9) to a hot water outlet 8. Hot water can be made available for withdrawal via the hot water outlet 8.

[0039] A hot water bypass valve 4 can be arranged in a bypass line 11 between the supply line 17 and the extraction line 15. The hot water bypass valve 4 can be controllable and electrically connected to a control unit 16 of the heating device 12.

[0040] A first temperature sensor 14, which can be electrically connected to the control unit 16, can be arranged in the supply line 17. The line from the water inlet 7 to the heat exchanger 3 can have a flow measuring device 10 for measuring the mass flow of water flowing through it, with which the withdrawal of water from the hot water outlet 8 can be detected.

[0041] According to a procedure proposed here, the Fig. 1The heater shown can be operated as follows: According to step a), the hot water bypass valve 4 is closed, so that when hot water is drawn off at the hot water outlet 8, the hot water is drawn from the storage tank 9. In other words, the hot water bypass valve 4 can always be closed when no hot water is drawn off and thus the flow measuring device 10 cannot detect a mass flow of water. According to step b), the hot water bypass valve 4 is opened when hot water flowing out of the heat exchanger 3 has reached a desired temperature. For example, a mass flow of water can be detected for this purpose by the flow measuring device 10, whereby the hot water bypass valve 4 initially remains closed and the water is drawn off from the (upper hot area) of the storage tank 9 and at the same time water flows into the storage tank 9 via the supply line.

[0042] Advantageously, the water in the (upper hot area) of the storage tank 9 is at the desired temperature, thus ensuring a high level of comfort, since water of the desired temperature can be discharged immediately after a water tap is opened. Only when the temperature at the outlet of heat exchanger 3 in the supply line 17 has reached the desired temperature with a determined water mass flow is the hot water bypass valve 4 opened, and water is drawn directly from heat exchanger 3.

[0043] A method proposed here can be implemented on the control unit 16 of the heater 12. For this purpose, the control unit can detect the temperature at the temperature sensor 14 and the mass flow at the flow measuring device 10 and switch the hot water bypass valve 4. List of reference symbols

[0044] 1Heat generator 2Circulation pump 3Heat exchanger 4Hot water bypass valve 5Heating return 6Heating flow 7Water inlet 8Hot water outlet 9Storage tank 10Flow meter 11Bypass line 12Heater 13Heating circuit 14Temperature sensor 15Extraction line 16Control unit 17Supply line

Claims

1. Heating appliance (12) having a water heating system comprising at least - a heat exchanger (3) connected to a water inlet (7), adapted to transfer a heat flow from a heating circuit (13) to a water flow for water heating, characterised in that the heating appliance further comprises: - a heat exchanger (3) connected to a water inlet (7), adapted to transfer a heat flow from a heating circuit (13) to a water flow for water heating: - a storage tank (9) arranged between the heat exchanger (3) and a hot water outlet (8) for holding drinking or service water, wherein a controllable hot water bypass valve (4) is arranged between an extraction line (15) and a supply line (17) of the storage tank (9) and is set up so that hot water can be conducted from the heat exchanger (3) past the storage tank (9) directly to the hot water outlet (8) when the bypass valve (4) is in an open position.

2. Heating appliance (12) according to claim 1, wherein the heat exchanger (3) is a plate heat exchanger.

3. Heating appliance (12) according to one of the preceding claims, wherein the storage tank (9) is a stratified storage tank and a line from the heat exchanger (3) opens into a lower cold region thereof.

4. Heating appliance (12) according to claim 3, wherein an extraction line leads from an upper hot region of the storage tank (9) to the water outlet (8).

5. Heating appliance (12) according to claim 3, wherein a flow measuring device (10) is arranged in a region between a water inlet (7) and the heat exchanger (3) and / or the heat exchanger (3) and the hot water bypass valve (4).

6. Heating appliance (12) according to one of the preceding claims, wherein a temperature sensor (14) is arranged such that a temperature of the water at the outlet of the heat exchanger (3) in a supply line (17) to the storage tank (9) can be measured.

7. Heating appliance (12) according to one of the preceding claims, comprising a control unit (16), a flow measuring device (10) and a temperature sensor (14).

8. A method of operating a heating appliance (12) according to claim 7, comprising at least the following steps: a) closing the hot water bypass valve (4) so that the hot water is withdrawn from the storage tank (9) when hot water withdrawal starts at the hot water outlet (8), b) Opening the hot water bypass valve (4) when the hot water flowing out of the heat exchanger (3) has reached the desired temperature.

9. A control unit (16) of a heating appliance (12) according to claim 7, adapted to perform a method according to claim 8.

10. A computer program comprising instructions that cause a heating appliance (12) according to claim 7 to perform a method according to claim 8.

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