Hot water storage and use of a heatable conduit section

Abstract

A hot water storage tank (1) is proposed, comprising a cold water inlet (16) with a pipe section (4) within the hot water storage tank (1) that can be heated by means of at least one heating element (5). According to one embodiment, the cross-sectional area (8, 9) of the pipe section (4) can increase from a first cross-sectional area (9) to a second cross-sectional area (8) in a flow direction (10) of the pipe section (4). Furthermore, the use of a heated pipe section (4) as a cold water inlet (16) within a hot water storage tank (1) is proposed.

Description

[0001] The invention relates to a hot water storage tank and a use of a heatable pipe section.

[0002] Hot water systems can include a hot water tank for storing the heated water. Particularly when using renewable energy sources such as solar thermal energy or heat pumps, conditions can be favorable for heat generation and hot water demand at different times. To ensure that the amount and temperature of solar-heated water requested by a user is always available, hot water tanks are used to store the heated water until needed.

[0003] In the event that there is not enough heat available from renewable energies or to use electricity generated by photovoltaics, hot water storage tanks can have electric heaters.

[0004] For example, DE 10 2016 012 921 A1 proposes a hot water storage tank having a heating flange device that can be inserted into the hot water storage tank via a flange. The heating flange device can comprise the cold water inlet, a hot water outlet, and at least one electric heating element. To maintain a (temperature) stratification in the hot water storage tank, a mixing limiter is provided, which can be designed as an impact guard or baffle plate and is intended to maintain the temperature stratification in the hot water storage tank even when cold water flows in. The heating flange device can improve the insulation of the hot water storage tank, as this has fewer perforations due to the combination of various connections in the heating flange.

[0005] The disadvantage is that this heating flange device cannot be used on existing hot water tanks because a suitable flange for the heating flange device is not provided or available. Furthermore, the hot water to be extracted is cooled again with cold water during transport through the lower temperature stratifications, which reduces user comfort and disrupts the temperature stratification. The heating flange device also extends into the hot water tank, reducing the available height for stratification.

[0006] Based on this, the object of the invention is to propose a hot water storage tank and the use of a heatable pipe section that at least partially overcome the described problems of the prior art. In particular, the hot water storage tank should be simple in design, offer high user comfort and high energy efficiency, and can also be created by converting an existing hot water storage tank. Last but not least, the accumulation of suspended matter or limescale on a heating device of the hot water storage tank should not reduce the heating output, or should only reduce it slightly.

[0007] 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 is pointed out 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.

[0008] A hot water tank contributes to this, which comprises a cold water inlet with a pipe section within the hot water tank that can be heated by means of at least one heating element.

[0009] A hot water tank is a hot water storage unit for supplying hot water, for example, to a building. The hot water tank can be designed as a buffer tank and / or a stratified storage unit. It can include a heat exchanger for transferring a heat flow, for example, for heat exchange with a heating circuit of a heating system. The heat exchanger can be designed, for example, as a pipe coil, which (when installed or assembled) can usually be located in a (geodetically) lower area of ​​the hot water tank.

[0010] The hot water tank can be designed to store heated or to-be-heated drinking or service water in a storage area. The hot water contained in the hot water tank can be heated, for example, by heat exchange with a heating circuit. Alternatively or in addition, a heat pump or a solar thermal system can be provided to heat the hot water contained in the hot water tank.

[0011] The hot water tank can have or contain a gas volume as an expansion area, particularly to compensate for volume fluctuations in the water held by the hot water tank caused by temperature-related fluctuations in water density. Thus, heating of the water contained in the water volume can lead to an increase in its volume, which can be compensated for by the gas volume. At least one (movable and / or deformable) separating element can be provided to divide the water volume and the gas volume.

[0012] For the extraction of hot water, the hot water tank can include a hot water outlet, which can be located, in particular, in a geodetically upper area of ​​the hot water tank. This advantageously allows water to be extracted from a temperature stratification with a high or highest temperature in the hot water tank in the upper area if a temperature stratification occurs in the hot water tank.

[0013] In order to refill the hot water that has been drawn off, the hot water tank has (at least) one cold water inlet, i.e. a supply of fresh water, often connected to a domestic water system or a water network.

[0014] In addition, the hot water tank has a (activatable and deactivatable) heating device with at least one heating element, with which water contained in the hot water tank or within the hot water tank can be heated. The heating device can, for example, heat water in the hot water tank (supplementarily and / or additionally) if heat is not provided or available using renewable energies. For this purpose, the heating device is in particular an electric heating device, for example comprising a resistance-based electric heating element. Thus, the heating element can (also) be operated with renewable energies, in particular electrical energy from a photovoltaic system. This ensures sensible use, for example, if there is no consumption of the generated electrical energy.

[0015] It is proposed that the incoming cold water is guided inside the hot water tank through a pipe section in which at least one heating element is arranged. A flow direction of the pipe section here refers to a direction from a passage through a wall of the hot water tank to the end (outlet) of the pipe section, or as a direction in which cold water is supplied to the hot water tank. The pipe section is located in the receiving area of ​​the hot water tank and thus leads through water contained in the hot water tank. When put into operation, the at least one heating element can heat the water contained in the hot water tank as well as the water flowing through the pipe section. The heat generated by the at least one heating element is advantageously transferred to the hot water tank without loss.

[0016] According to one embodiment, the pipe section can end geodetically in a lower area of ​​the hot water tank. The lower area can refer to the lower 20 percent [%] or 10% of the height of the hot water tank's receiving area in the installed position.

[0017] According to one embodiment, the cold water inlet and a power supply for the at least one heating element can be routed through a common passage through the wall of the hot water tank. Advantageously, the insulation of the hot water tank only needs to be penetrated once, and heat loss from the hot water tank can be reduced. It is understood that the common passage of the cold water inlet and power supply for the at least one heating element can also be used for other lines, for example, connections for measuring devices such as temperature sensors.

[0018] According to one embodiment, the joint feedthrough can be located in a middle or upper area of ​​the hot water tank. For example, the feedthrough could also be located at the top of the hot water tank, with the pipe section leading downwards in a lower area. The middle or upper area can refer to the upper 30%, 40%, or 50% of the height of the hot water tank's receiving area in the installed position.

[0019] Alternatively, the joint outlet can also be located in a lower area or geodetically on the underside of the hot water tank. This can be structurally advantageous, for example, in wall-mounted hot water tanks.

[0020] According to one embodiment, the at least one heating element can be a heating wire arranged on the line section in the form of a coil such that cold water flowing through the line section is heated or can be heated. The heating wire can be configured to convert electrical current into heat. The heating wire can, in particular, be integrated into a wall of the line section. For example, the at least one heating wire can be integrated into the wall of the line section in the form of a coil. For this purpose, the heating wire can be introduced into the wall, for example, during the production of the line section using an injection molding process.

[0021] According to one embodiment, the at least one heating element can be arranged on or in the line section in such a way that heat generated by the heating element is transferred essentially only to the water flowing through the line section. Advantageously, heat generated by the at least one heating element can thus be transferred largely exclusively to the cold water flowing through the line section and not to the water surrounding the line section in the receiving area of ​​the hot water tank, whereby a developed temperature stratification in the hot water tank is advantageously not disrupted. For this purpose, the heating element can be introduced, for example, in the region of the inner wall of the line section. Alternatively or cumulatively, the line section can also additionally have heat-insulating material arranged between the at least one heating element and an outer wall (which is in contact with the water in the hot water tank).

[0022] According to one embodiment, the at least one heating element can be arranged in the pipe section in such a way that the cold water flowing through the pipe section can completely flow around it. This advantageously also ensures almost exclusive heat transfer to the cold water flowing through the pipe section.

[0023] According to one embodiment, a pipe cross-section (i.e., the flow cross-section available for the cold water flow) of the pipe section can increase in a flow direction. In other words, the cross-sectional area of ​​the pipe section available for the cold water flow can increase with increasing length, starting from the passage through the wall of the hot water tank. Advantageously, the flow velocity of the cold water in the pipe section decreases in the flow direction, and the water exits at a lower flow velocity, thereby mitigating any disruption to the temperature stratification caused by the water flow exiting the pipe section.

[0024] According to one embodiment, the pipe cross-section of the pipe section can increase by a factor of 2, 3 or 4 from the passage through the wall of the hot water tank to the end.

[0025] According to one embodiment, the temperature of the hot water contained in the hot water tank can be detected. In particular, multiple temperatures can be detected at different levels within the water volume to enable temperature stratification. Detecting the temperature of the water in the hot water tank can facilitate automated implementation of a method proposed here.

[0026] According to a further aspect, the use of a heatable pipe section as a cold water inlet within a hot water storage tank is proposed. The heatable pipe section can extend, in particular, from a passage through a wall of the hot water storage tank to an end, in particular arranged in a lower region of the hot water storage tank. The heatable pipe section can, in particular, comprise at least one heating element, which can be arranged, in particular, inside the pipe section or in the wall of the pipe section. The passage through the wall of the hot water storage tank can be effected by a flange or a jointly used sleeve shared by the cold water inlet and lines for supplying energy to the at least one heating element. Advantageously, penetration points can thus be reduced by thermal insulation of the hot water storage tank, and thus also the heat loss thereof.

[0027] According to one embodiment of the use, a flow cross-section of the line section can increase in a flow direction of the line section.

[0028] The details, features, and advantageous embodiments discussed in connection with the hot water storage tank may also occur during use, and vice versa. In this respect, reference is made in full to the explanations therein for a more detailed characterization of the features.

[0029] Thus, a hot water storage tank and a use are provided here that at least partially solve the problems described with reference to the prior art. In particular, the hot water storage tank and the use at least contribute to providing a simply constructed and very robust hot water storage tank. Furthermore, a large surface area for heat transfer of the at least one heating element can effectively prevent restrictions in heat transfer due to limescale deposits. Furthermore, an existing hot water storage tank can also be easily converted into the hot water storage tank presented here.

[0030] 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 hot water storage tank proposed here and Fig. 2: a pipe section of a hot water storage tank proposed here.

[0031] Fig. 1 shows, by way of example and schematically, a hot water storage tank 1 proposed here. This can have a receiving area 12 enclosed by a wall 2. The receiving area 12 can comprise an expansion area 14 in the upper area of ​​the receiving area 12 (in the installed position), in which a pressurized gas, in particular air, can be contained. The expansion area 14 can also represent an expansion area 14 for compensating for changes in the volume of water held in a water volume 15 due to temperature fluctuations.

[0032] The receiving area 12 can separate the gas volume from the water volume 15 by means of a separating element 13 in the expansion area 14. The separating element 13 can, in particular, have a density that is lower than the density of water and thus float on the contained water or the water volume 15.

[0033] The hot water tank 1 can comprise a cold water inlet 16 for supplying cold water from a water network or a well, as well as a hot water outlet 7 for withdrawing hot water. The hot water outlet 7 can be arranged in the upper region of the hot water tank 1, thus enabling easy withdrawal of hot water from an upper layer with a high water temperature. The cold water inlet 16 can lead through a passage 3 through the wall 2 of the hot water tank 1 and, in the receiving region 12, via a line section 4 into a lower region 6 of the hot water tank 1. The line section 4 can be wrapped with a heating element 5, configured to convert electrical energy into heat and transfer it to the cold water flowing through the line section 4.

[0034] Fig.2shows, by way of example and schematically, a line section 4 of a hot water tank 1 presented here. In an area close to the feedthrough 3, the line section 4 can have a first line cross-section 9 which increases in a flow direction 10 of the line section 4. At one end of the line section 4 in the lower area 6 of the hot water tank 1, the line cross-section can be increased to a second line cross-section 8. The second line cross-section 8 can correspond to twice the first line cross-section 9. At least one heating element 5 in the form of a resistance-based heating wire can be wound around the line section. A power supply 11 as an electrical line can be guided with the line section 4 through the feedthrough 3.

[0035] As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and therefore do not necessarily specify any interdependence and / or sequence of these objects, quantities, or processes. Should a dependence and / or sequence be required, this is explicitly stated here or will be obvious to the person skilled in the art upon studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or part of the majority of these components, but this is not mandatory. List of reference symbols

[0036] 1Hot water tank 2Wall 3Flow-through 4Pipe section 5Heating element 6Lower section 7Hot water outlet 8Second pipe cross-section 9First pipe cross-section 10Flow direction 11Energy supply 12Receiving area 13Separating element 14Expansion area 15Water volume 16Cold water inlet

Claims

1. Hot water tank (1), at least comprising a cold water inlet (16) with a line section (4) within the hot water tank (1) that can be heated by means of at least one heating element (5).

2. Hot water storage tank (1) according to claim 1, wherein the pipe section (4) ends in the geodetically lower region (6) of the hot water storage tank (1).

3. Hot water tank according to one of the preceding claims, wherein the cold water inlet (16) and an energy supply (11) of the at least one heating element (5) are guided through a common passage (3) through the wall (2) of the hot water tank (1).

4. Hot water tank (1) according to claim 3, wherein the common passage (3) is arranged in a middle or upper region of the hot water tank (1).

5. Hot water tank (1) according to one of the preceding claims, wherein the at least one heating element (5) is a heating wire arranged on the line section (4) in the form of a winding.

6. Hot water tank (1) according to one of the preceding claims, wherein a line cross-section (8, 9) of the line section (4) increases in a flow direction (10) of the line section (4) from a first line cross-section (9) to a second line cross-section (9).

7. Use of a heatable pipe section (4) as a cold water inlet (16) within a hot water tank (1).

8. Use according to claim 7, wherein a line cross-section (8,9) of the line section (4) increases in a flow direction (10) of the line section (4).

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