Hot water storage tank and use of a heated pipe 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

The invention relates to a hot water storage tank and to a use of a heatable line section.Installations for supplying hot water can comprise a hot water store for storing the heated water. Particularly when using renewable energies such as solar heat or heat pumps, good conditions for heat generation and a demand for hot water can be present at different times. In order to be able to dispense water heated by solar heat at the same time as the quantity or temperature requested by a user, hot water storage devices are used with which the heated water can be stored until use.In the event that not sufficient heat is available from renewable energies or for the use of electric current generated by photovoltaics, hot water storage devices can have electric heaters.For example, DE 10 2016 012 921 A1 proposes a hot water reservoir, which has a heating flange device, which can be introduced into the hot water reservoir at one flange. The heating flange device may comprise the cold water inlet, a hot water outlet and at least one electric heating element. In order to maintain a (temperature) layering in the hot water storage, a mixing limiter is provided, which can be designed as an impact protection or baffle plate and is intended to maintain the temperature layering in the hot water storage even when cold water flows in. The heating flange device can improve the insulation of the hot water storage tank, since it has fewer openings by combining different connections in the heating flange.This heating flange device cannot be used on existing hot water storage tanks, since a corresponding flange is not provided or present for the heating flange device. In addition, hot water to be drawn off is cooled again during transport through the lower temperature layers with cold water, as a result of which the user comfort is restricted and the temperature layers are also disturbed. The heating flange device also protrudes into the hot water reservoir, whereby the available overall height for forming layers is reduced.Proceeding from this, it is an object of the invention to propose a hot water storage tank and a use of a heatable line section which at least partially overcome the outlined problems of the prior art. In particular, the hot water storage device should be of simple construction, offer high user comfort and high energy efficiency and can also be formed by re-upgrading an existing hot water storage device. Not least, an accumulation of suspended matter or lime on a heating device of the hot water storage should not reduce the heating power or only slightly reduce it.These objects are achieved by the features of the independent 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 desired, technologically meaningful manner and define further embodiments of the invention. In addition, the features specified in the patent claims are more precisely described and explained in the description, further preferred embodiments of the invention being presented.A hot water storage tank contributes to this, which comprises a cold water inlet with a line section within the hot water storage tank, which line section can be heated by means of at least one heating element.The hot water storage is a hot water storage for supplying hot water, for example of a building. The hot water storage can be designed as a buffer store and / or a stratified store. It can comprise 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 (in the assembled or assembled state) can generally be arranged in a (geodetically) lower region of the hot water reservoir.The hot water storage can be configured to receive heated or heated drinking or service water in a receiving region. In this case, the hot water contained in the hot water storage tank can be heated, for example, by means of heat exchange with a heating circuit. Alternatively or cumulatively, a heat pump or a solar thermal installation for heating the hot water contained in the hot water storage can also be provided.The hot water storage tank can have or contain a gas volume as expansion region, in particular for compensating volume fluctuations of the water absorbed by the hot water storage tank, triggered by temperature-induced fluctuations in the density of water. Thus, heating the water contained in the water volume can lead to an increase in its volume, which can be compensated by the gas volume. At least one (movable and / or deformable) separating element can be provided for dividing the water volume and the gas volume.For the extraction of hot water, the hot water storage can comprise a hot water outlet, which can be arranged in particular in a geodetically upper region of the hot water storage. When forming a temperature layering in the hot water storage tank in the upper region, water can thus advantageously be taken from a temperature layering with a high or the highest temperature in the hot water storage tank.In order to replenish hot water taken, the hot water storage tank has (at least) one cold water inlet, that is to say a supply of fresh water, frequently connected to a domestic water installation or a water network.In addition, the hot water storage device has a (activatable and deactivatable) heating device having at least one heating element, by means of which water contained in the hot water storage device or within the hot water storage device can be heated. The heating device can, for example, heat water (additionally and / or additionally) present in the hot water storage device in the absence of provision or availability of heat by renewable energies. For this purpose, the heating device is in particular an electrical heating device, for example comprising a resistance-based electrical heating element. The heating element can thus (also) be operated with renewable energies, in particular electrical energy of a photovoltaic system. Thus, for example, a reasonable use can be ensured in the absence of a decrease in the generated electrical energy.It is proposed that the incoming cold water in the interior of the hot water storage tank be guided through a line section in which at least one heating element is arranged. A direction of flow through the line section here denotes a direction from a passage through a wall of the hot water tank to the end (outlet) of the line section, or as a direction in which cold water is supplied to the hot water tank. The line section is located in the receiving region of the hot water reservoir and thus conducts water contained in the hot water reservoir. The at least one heating element can heat the water contained in the hot water storage device as well as the water flowing through the line section when it is put into operation. Advantageously, the heat generated by the at least one heating element is dissipated into the hot water reservoir without loss.According to one embodiment, the line section can end geodetically in a lower region of the hot water reservoir. The lower region can thereby denote the lower 20 percent [%] or 10% based on the height of the receiving region of the hot water storage in the set-up position.According to one embodiment, the cold water inlet and an energy supply of the at least one heating element can be conducted through the wall of the hot water reservoir by a common lead-through. It is thus advantageous for the warm water reservoir to be insulated only once, and a waste heat flow of the warm water reservoir can be reduced. It is understood that the joint passage of cold water inlet and energy supply of the at least one heating element can also be used by other lines, for example connections of measuring devices such as temperature sensors.According to one embodiment, the joint feedthrough can be arranged in a central or upper region of the hot water reservoir. By way of example, the leadthrough could also be effected on the upper side of the hot water tank and the line section could lead downward in a lower region. The middle or upper region can thereby designate the upper 30%, 40% or 50% with respect to the height of the receiving region of the hot water storage in the set-up position.Alternatively, the joint feedthrough can also be arranged in a lower region or geodetically on the underside of the hot water storage device. This can be of constructional significance, for example, in the case of wall-suspended hot water storage tanks.According to one configuration, the at least one heating element can be a heating wire which is arranged on the line section in the form of a winding in such a way that cold water flowing through the line section is heated or can be heated. The heating wire may be configured to convert electrical current into heat. The heating wire can be integrated in particular into a wall of the line section. By way of example, the at least one heating wire can be integrated in the wall of the line section in the form of a winding. For this purpose, the heating wire can be introduced into the wall, for example, during the production of the line section by an injection molding method.According to one configuration, 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 substantially only emitted to the water flowing through the line section. Advantageously, heat generated by the at least one heating element can thus be transferred as far as possible exclusively to the cold water flowing through the line section and not to the water surrounding the line section in the receiving region of the hot water storage, as a result of which advantageously a temperature layering formed in the hot water storage is not disturbed. 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 be arranged heat-insulating material between the at least one heating element and an outer wall (which is in contact with the water located in the hot water store).According to one configuration, the at least one heating element can be arranged in the line section in such a way that the cold water flowing through the line section can flow completely around it. In this way, an almost exclusive heat transfer to the cold water flowing through the line section can advantageously also be ensured.According to one embodiment, a line cross section (i.e. the flow cross section available for the flow of the cold water) of the line section can increase in a flow direction. In other words, the cross-sectional area of the line section available for the flow of the cold water can increase with increasing length of the latter, starting from the passage through the wall of the hot water reservoir. Advantageously, the flow speed of the cold water in the line section thus decreases in the direction of flow through the latter, and the water exits at a low flow speed, as a result of which disturbance of the temperature lamination by the water flow exiting from the line section can be reduced.According to one embodiment, the line cross section of the line section can increase by a factor of 2, 3 or 4 from the passage through the wall of the hot water reservoir to the end.According to one configuration, a temperature of the hot water contained in the hot water storage can be detected. In particular, a plurality of temperatures can be detected at different heights of the water volume in order to enable temperature detection of the temperature layering. Detecting the temperature of the water in the hot water storage can promote an automated execution of a method proposed here.According to a further aspect, a use of a heatable line section as a cold water inlet within a hot water storage is proposed. The heatable line section can extend in particular from a feedthrough through a wall of the hot water reservoir to one end, in particular arranged in a lower region of the hot water reservoir. The heatable line section can in particular comprise at least one heating element, which can in particular be arranged in the interior of the line section or in the wall of the line section. The passage through the wall of the hot water storage can be effected by a flange or a shared socket shared by the cold water inlet and lines for supplying power to the at least one heating element. In this way, puncture points can be advantageously reduced by heat insulation of the hot water storage tank and thus also a waste heat flow of the latter.According to one configuration of the use, a flow cross section of the line section can increase in a flow direction of the line section.The details, features and advantageous embodiments discussed in connection with the hot water storage can also correspondingly occur during use and vice versa. In this respect, reference is made to the full extent of the details given there for more detailed characterization of the features.Thus, a hot water storage device and a use are provided here which at least partially solve the problems described with reference to the prior art. In particular, the hot water storage device and the use contribute at least to the provision of a simply constructed and very robust hot water storage device. In addition, a large surface area for the heat transfer of the at least one heating element can effectively prevent a restriction of the heat transport due to alkane bearings. Furthermore advantageously, an existing hot water storage can also be easily converted into a hot water storage presented here.The invention and the technical field are explained in more detail below with reference to the attached figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments listed. 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 constituent parts and findings from the present description. In particular, it should be pointed out that the figures and in particular the size relationships illustrated are only schematic. It shows: FIG. 1 : a hot water storage device proposed here, and FIG. 2 : shows a line section of a hot water storage device proposed here.FIG. 1 shows, by way of example and schematically, a hot water storage device 1 proposed here. The receiving region 12 can comprise an expansion region 14 in the upper region (in the set-up position) of the receiving region 12, in which region a pressurized gas, in particular air, can be contained. The expansion region 14 can also represent an expansion region 14 for compensating changes in the volume of water absorbed in a water volume 15 due to temperature fluctuations.The receiving region 12 can separate the gas volume from the water volume 15 by a separating element 13 in the expansion region 14. The separating element 13 can have, in particular, a density which is lower than the density of water and thus floats on the contained water or the water volume 15.The hot water storage 1 can comprise a cold water inlet 16 for supplying cold water from a water network or well and a hot water outlet 7 for removing hot water. The hot water outlet 7 can be arranged in the upper region of the hot water reservoir 1 and thus make it possible to easily remove 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 reservoir 1 and in the receiving region 12 via a line section 4 into a lower region 6 of the hot water reservoir 1. The line section 4 can be wound around with a heating element 5 in order to convert electrical energy into heat and to transfer it to the cold water flowing through the line section 4.FIG. 2 shows, by way of example and schematically, a line section 4 of a hot water reservoir 1 presented here. In a region close to the feedthrough 3, the line section 4 can have a first line cross section 9, which increases in size in a flow direction 10 of the line section 4. At one end of the line section 4 in the lower region 6 of the hot water reservoir 1, the line cross section can be enlarged to a second line cross section 8. The second line cross section 8 can correspond to twice the first line cross section 9. Around the line section at least one heating element 5 in the form of a resistance-based heating wire can be wound. A power supply 11 as an electrical line can be led with the line section 4 through the feedthrough 3.As a precautionary measure, it should be noted that the numerical words used here ("first", "second",... ) are primarily (only) used for distinguishing a plurality of articles, sizes or processes of the same type, that is to say in particular do not necessarily specify a dependence and / or sequence of these articles, sizes or processes with respect to one another. If a dependence and / or sequence is required, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described configuration. If a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or a part of the plurality of these components, but this is not obligatory.List of reference characters1 Hot water storage 2 wall 3 feedthrough 4 line section 5 heating element 6 lower region 7 hot water outlet 8 second line cross section 9 first line cross section 10 flow direction 11 energy supply 12 receiving region 13 separating element 14 expansion region 15 water volume 16 cold water inletReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2016 012 921 A1

[0004]

Claims

Hot water storage tank (1), at least comprising a cold water inlet (16) with a line section (4) within the hot water storage tank (1) that can be heated by means of at least one heating element (5).Warning water storage device (1) according to Claim 1, wherein the line section (4) ends in the geodetically lower region (6) of the hot water storage device (1).Hot water storage device 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 feedthrough (3) through the wall (2) of the hot water storage device (1).Hot water storage (1) according to Claim 3, wherein the common feedthrough (3) is arranged in a central or upper region of the hot water storage (1).Hot water storage device (1) according to one of the preceding claims, wherein the at least one heating element (5) is a heating wire which is arranged on the line section (4) in the form of a winding.Hot water storage device (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).Use of a heatable line section (4) as cold water inlet (16) within a hot water storage tank (1).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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