Bivalent multifunction storage system

Abstract

The invention relates to a multi-functional storage system 1 for generating heating energy and for domestic hot water heating. The system comprises a multi-zone stratified storage tank with a buffer storage zone 5 and a hot water charging zone 6 above it, featuring a storage medium 3 with stratified charge at different temperatures; a counterflow domestic hot water heater 10, with a domestic hot water line 11 and a flow line 14 such that a flow gap 15 exists between them; a domestic hot water charging pump 18 for charging the flow gap 15 with the storage medium 3; a control unit 21 for operating the multi-functional storage system 1; and an electric heating element 20.1, the heating surface of which is arranged within the hot water charging zone 6, with the heating area extending at most to the eighth coil of the domestic hot water line 11. The invention also relates to a method for operating the multi-functional storage system 1. (Fig. 1)

Description

[0001] The invention generally relates to a bivalent multifunctional storage system according to the preamble of the main claim. This system comprises a buffer storage tank as a component of a heating system and a device for hot water preparation.

[0002] Multifunctional storage tanks within the meaning of the invention include, in particular, buffer tanks, which are designed, for example, as multi-zone stratified storage tanks with integrated hot water preparation for domestic water. The buffer tank is connected to an external heat source, for example, a heating system and / or a heat pump or a solar system, which, via a flow line, loads the buffer tank with heating water at the temperature required for space heating. This heat source is referred to as external below, as it is not part of the multifunctional storage system.

[0003] To generate heat and hot water, the storage tank is filled with heating water, although any other heat-carrying storage medium is also suitable. The storage medium in the storage tank is heated by means of the heat source or by a heating surface arranged inside the storage tank, which is connected to a heat source, e.g. a heat pump, in such a way that there is always a stratified charge in the storage tank with several layers of the storage medium at different temperatures. The temperature stratification is set and maintained in such a way that the stratified charge has at least one buffer storage zone and at least one hot water charging zone above it. To create and maintain the stratification of the storage medium, various designs of the stratified storage tank and / or the use of suitable baffles, separating discs orPerforated discs with an outer annular gap, flow guide devices, and other internal components are used in the storage tank. If the hot water charging zone is not separated from the buffer storage zone by a perforated disc, the specialist can also identify the two zones of the multi-zone stratified storage tank based on other characteristics, for example, the density and pitch of the coils or the temperature distribution in the storage medium.

[0004] A counterflow domestic water heater is typically integrated into the multi-zone stratified storage tank to generate hot water. For this purpose, the inlet of the domestic water line for cold water is located on the cold side of the storage tank, and the outlet for hot water is located on the warm side. The counterflow domestic water heater comprises the domestic water line and a flow line that surrounds the domestic water line and forms a flow gap. The heat exchanger surface is designed, in terms of material and, if necessary, also the surface design of the line, to ensure effective heat transfer to the domestic water flowing in the line.

[0005] The counterflow domestic water heater further comprises a domestic water charging pump for charging the flow gap with the storage medium in which the counterflow domestic water heater is located. Of the two lines used in counterflow, the domestic water flow runs from bottom to top, and the storage medium flow in the flow gap runs from top to bottom. To generate the flow in the flow gap, the storage medium is pumped from the upper area of ​​the hot water charging zone into the inlet of the flow gap by means of the domestic water charging pump. The inlet is usually located one or two coils below the outlet of the domestic water line from the storage tank, so that these coils are in direct thermal contact with the storage medium in the storage tank.The counterflow domestic water heater also includes sensors and a circulation line, with the circulation line connecting to the domestic water line at the return connection. The amount of water flowing through the circuit depends directly on the heat input from the storage medium, with the temperature stratification in the storage medium being maintained as much as possible.

[0006] The use of such an instantaneous water heater improves the cooling of the storage medium to near cold water temperature, thus improving the discharge efficiency of the multifunctional storage tank. Its basic structure within the multi-zone stratified storage tank is also well known to those skilled in the art.

[0007] A multifunctional storage system also includes a control unit that is suitable and configured to operate the system. Such a control unit communicates with temperature sensors that measure the temperatures of the storage medium at various positions in the storage tank, such as the temperature stratification, particularly in the upper area of ​​the storage tank, as well as the temperature of the domestic water, particularly at its tap. It is also designed to control the pumps of the multifunctional storage system, particularly the domestic water charging pump and optionally additional pumps.

[0008] A multi-zone stratified storage tank with a buffer tank and integrated hot water preparation is known from DE 10 2010 028 198 A1. Such a heating system has a heat pump as the heat source for heating the storage medium in the storage tank. The storage medium has a temperature stratification that should be disturbed as little as possible during operation of the multi-zone stratified storage tank. Other heat sources for buffer heating systems are also known. The hot water preparation system implemented in such a multi-zone stratified storage tank operates according to the countercurrent flow principle and comprises a tubular, usually coiled, domestic water line, which serves as a heat exchanger surface and is made of a corrosion-resistant material. The domestic water line is surrounded by a flexible, temperature- and pressure-resistant flow line in such a way that an annular flow gap is created.The flow gap opens into the buffer tank, open at least at the top, in this design on both sides, at a distance from the top and bottom walls of the storage tank, allowing the storage medium to flow through the flow gap and come into thermal contact with the domestic water line using a charging pump that pushes from above or alternatively draws from below. If the lower end of the flow gap does not open into the buffer tank in alternative designs, it is fluidly connected to the lower area of ​​the storage volume, for example, via a pipe loop (DE 298 16 006 U1, DE 10 2009 026 420 A1).

[0009] In the multi-zone stratified storage tank described in DE 10 2009 026 420 A1, the storage volume is also divided into the lower, temperature-stratified buffer storage zone and the warm water charging zone above it. A heat pump is used as the heat source. The heat pump's refrigerant is fed through the storage tank via a coiled pipe, heating the storage medium within it according to the desired temperature stratification. The charging pump generates the flow of the medium in the flow gap opposite to the flow direction of the domestic water by feeding warm water from the upper, hot area of ​​the hot water charging zone into the upper area of ​​the flow gap.

[0010] The heat exchanger surface of the counterflow domestic water heater is designed for optimal heat transfer between the storage medium flowing in the flow gap and the domestic water flowing in the domestic water pipe, for example by the choice of the material of the heat exchanger surface, the coiling of the pipes and by suitable structuring that increases the surface area and / or other known designs of the heat exchanger surface.

[0011] Such multifunctional storage systems are increasingly being designed as bivalent systems. In energy generation, the term "bivalent" refers to the combination of two different heat energy generators to heat the heating and / or domestic water.

[0012] The known bivalent solutions, when the heat is supplied from the heat source via district heating, heat pumps, or solar thermal collectors, are characterized by relatively high production costs and still relatively low efficiency. This low efficiency results from the operating temperatures of over 60°C required for domestic water heating for hygiene reasons. Furthermore, every domestic water withdrawal means that the heating system must frequently provide heat to bring the fluid in the storage tank to the temperature required for domestic water heating and, if necessary, heating.

[0013] To reduce the relatively high cycle times of the heating system, screw-in heaters are increasingly being integrated into the storage tank. These heaters can be powered by a photovoltaic (PV) system and serve as an additional heat source for heating the storage medium. For example, EP 3812678 A1 describes such an electric heater, also commonly referred to as an electric cartridge or electric heater, which protrudes into the cylindrical flow line surrounding the coiled domestic water line to heat the medium in the flow line.

[0014] E-cartridges are generally known as current-carrying heating coils, whose basic shape is essentially rod-shaped, but other shapes suitable for the purpose of the invention can also be used. The heating coil can have a heat-conducting coating. A wide variety of designs are known to those skilled in the field of heating technology.

[0015] To generate the energy needed to heat the storage medium, numerous electric cartridges are sometimes integrated. These operate at different power levels depending on the respective heat energy demand and are integrated into the buffer storage layer corresponding to their power output. While such a solution allows the energy required by the heating system to be reduced, particularly during the warmer and light-intensive seasons, and replaces it with solar energy, the technical complexity of the heating cartridges and their control system, as well as the associated influence on the stratification in the storage tank, negatively impacts efficiency.

[0016] The object of the invention is therefore to provide an advantageous concept which is suitable for reducing the manufacturing and operating costs of multifunctional storage systems for heat pumps, district heating and other heat sources with hot water preparation and for improving the efficiency.

[0017] In addition, it is desirable to increase the utilization of solar energy from a photovoltaic (PV) system owned by the operator of the multifunctional storage system and to use the PV surplus as far as possible by the operator themselves.

[0018] The object is achieved with a bivalent multifunctional storage system according to the main claim and a method for operating such a multifunctional storage system according to claim 8: Preferred embodiments of the invention are formulated in the dependent claims related thereto.

[0019] In relation to the invention, the term "bivalent multifunctional storage system" encompasses a primary heat generator, which supplies at least the base load and, in the event that the secondary energy source is temporarily unable to supply energy, the entire energy supply, and at least one electric cartridge, which is operated by a photovoltaic system. The primary heat generator can be, for example, a combustion heating system, district heating, or another heat generator.

[0020] The object is achieved by the subject matter of claim 1, wherein the multifunctional storage system comprises the following components: a multi-zone stratified storage tank with a storage container for receiving the storage medium, wherein the multi-zone stratified storage tank comprises devices for forming a stratified charge generated by different temperatures of the storage medium such that a hot water charging zone is formed above a buffer storage zone such that the temperature of the storage medium increases with increasing height in the storage container;a countercurrent domestic water heater, which extends at least partially through the hot water charging zone, wherein the countercurrent domestic water heater has a domestic water line designed as a heat exchanger surface, the domestic water outlet of which is located above its domestic water inlet, and a flow line concentrically enclosing the domestic water line such that a flow gap is formed between the two lines, wherein the upper inlet and the lower outlet of the flow gap openly open into the storage medium; wherein the inlet of the flow gap has a distance A from the uppermost inner end of the tank wall;a domestic hot water charging pump, designed to charge the flow gap with storage medium, the suction side of which is fluidically connected to the upper region of the volume of the storage tank located above the inlet of the flow gap and the pressure side of which is fluidically connected to the inlet of the flow gap, a control unit, designed and configured to operate the multifunctional storage system, at least one electric cartridge, also referred to here as E-cartridge for short, the heating surface of which is arranged in a heating area within the hot water charging zone for heating the storage medium, at a distance E, measured from the uppermost inner end of the tank wall of the storage tank to the lower edge of the heating surface of the E-cartridge, the heating area extending at most to the eighth coil of the domestic hot water pipe.

[0021] Various known storage types can be used as multifunctional storage tanks according to the invention. A buffer storage tank, as described above in relation to the prior art, is known from DE 10 2010 028 198 A1. In DE 10 2009 026 420 A1, the buffer storage zone and the hot water charging zone are decoupled from each other by a perforated separating disc with an annular gap. Both applications are incorporated herein by reference.

[0022] For domestic water heating according to the invention, the at least one electric cartridge is integrated in the upper, hot heating area of ​​the hot water charging zone without protruding into the flow gap in which the domestic water is heated by means of the storage medium flowing through from top to bottom.

[0023] According to the invention, the heating zone, in which the electric cartridge heats the storage medium beyond the usual temperature stratification, is located in the upper region of the storage tank. The additionally heated storage medium is pumped into the inlet of the flow gap, where the domestic water is already significantly warmed, and receives an additional temperature boost both in the flow gap and above it. This makes it possible to reduce the primary energy required for the multifunctional storage system, in particular the timing of the heating system for domestic water heating. Despite the additional heating of the storage medium in the heating zone, the temperature stratification below is not or only slightly affected, since the heated storage medium is pumped directly into the flow gap, meaning the additional energy from the electric cartridge is used primarily for domestic water heating.

[0024] According to the invention, such electric cartridges can be used that can be placed in the hot water charging zone according to the following description and operated at the proposed output. Their output can be fixed, stepwise adjustable, or modulated (continuously adjustable), with an automatic temperature limiter serving to protect the electric cartridge. The heating surface of the at least one electric cartridge extends into the storage medium through a specially designed opening in the wall of the storage tank.

[0025] The distance between the E-cartridge and the upper wall of the storage tank is referred to as E, measured from the inner highest point of the tank wall to the lowest point of the E-cartridge's heating surface. The distance from the upper inlet of the flow gap to said highest point of the storage tank wall is referred to as A, where A is measured to the lowest point of the opening in the flow line wall at its inlet.

[0026] According to the invention, the heating area extends up to the eighth coil of the domestic water line, optionally up to the seventh, sixth, fifth, fourth, third, or second coil. The coils of the domestic water line are always counted from the top of the storage tank downwards. The uppermost inner end of the tank wall also serves as a reference for measuring the distances A for the inlet of the flow gap and E for the lower edge of the heating surface of the electric cartridge located in the storage medium.

[0027] Reference to the lower edge of the heating surface of the electric cartridge serves only to clearly define the heating area for the purpose of describing the invention and is not suitable for capturing the thermal area actually influenced by the one or more electric cartridges in the hot water charging zone. If the defined lower edge of the hot area is of little or no importance for the respective aspect described, this area will also be referred to below as the "hot area."

[0028] The arrangement "between the coils" means that the respective electric cartridge is inserted horizontally between two adjacent coils within this area, although deviations from the horizontal position are possible depending on the distance between the coils. For example, the at least one electric cartridge is inserted between the second and third, the third and fourth, or the fourth and fifth coils, etc. If multiple electric cartridges are used for domestic water heating according to the invention, they can be distributed around the circumference between the same coils or between different coils within the specified area, optionally also distributed around the circumference.

[0029] It has been shown that by positioning the electric cartridge in the heating section of the storage tank up to the eighth coil of the domestic hot water line (counting from the top), and within the hot water charging zone, the domestic hot water can be heated to the required temperature effectively and with minimal impact on the temperature stratification of the storage medium. If the hot water charging zone is shortened, the electric cartridge should obviously be positioned higher than the eighth coil.

[0030] According to one embodiment of the invention, the control unit is designed and configured to operate the multifunctional storage system, in particular the at least one e-cartridge, using the energy of an external photovoltaic system (PV system), i.e., one not belonging to the invention, preferably its PV surplus. PV surplus refers to that portion of the solar energy generated by a PV system that cannot be used by the operator of the PV system itself and is therefore fed into the grid.

[0031] For this purpose, the electric cartridge is at least communicatively connected to the PV system and configured for a power range, for example, up to a five-digit wattage. This power range is suitable for current PV systems to use solar energy, and in particular the PV surplus, for domestic water heating. Depending on the size of the storage tank, the amount of regular domestic water drawn, and the output of the PV system, other controllable power ranges may also be required. Future developments in PV systems and electric cartridges will also make other controllable power ranges possible. The power of the electric cartridge can be constant, modulated, or adjustable in stages across the usable power range, so that the power available from the PV surplus can be optimally used to cover the power required for domestic water heating.Continuous control from 0 to 100% of the available power range is possible, for example, using pulse width modulation.

[0032] The same applies to the use of multiple electric cartridges, whereby these can have the same or different outputs or output ranges, depending on the output generated by the PV system or required due to domestic water consumption. Cascading electric cartridges, i.e., connected in series, can be used and connected one after the other. Stepwise coordinated electric cartridges, used depending on the current situation, are also possible. The outputs and / or output ranges can be coordinated in such a way that the resulting PV surplus can be optimally used for domestic water heating.

[0033] For example, the control unit comprises an energy meter or is communicatively connected to one. An energy meter serves the purpose of, and is designed and configured to, determine the surplus energy available from the PV system based on a comparison with the preset feed-in energy. The energy meter can also be designed to implement the communicative connection of the electric cartridge to the external PV system. It controls or regulates the at least one or more electric cartridges depending on the power required to achieve the required domestic hot water temperature and / or depending on the available PV surplus. An energy meter is known as a device for measuring electricity consumption and is communicatively connected to the electric cartridge via a cable or radio connection for the purpose of regulating it, so that the power of the electric cartridge can be adapted to the available and measured PV surplus.The energy meter can also be configured to receive measured values ​​from the e-cartridge, such as the temperature at the heating coil, the set safety temperature limit and the temperatures at other measuring points in the storage medium, and to evaluate them based on predefined parameters.

[0034] The arrangement of at least one or more electric cartridges in the heating zone depends on various parameters of the storage tank and the counterflow domestic water heater, such as the volume and diameter of the storage tank, the width of the flow gap, the pitch of the coils, the temperature stratification of the storage medium, and others. It has proven advantageous to arrange the electric cartridge below the open outlet of the flow gap. This variant is characterized in that the distance E, defining the position of the electric cartridge, is greater than the distance A, defining the position of the upper inlet of the flow gap. In this embodiment, the coils running directly adjacent to the electric cartridge are enclosed by the flow line. A coil is considered to be arranged directly adjacent to the electric cartridge if it is located directly next to the electric cartridge in a side view.A coil is generally considered to be a section of a coiled cable which forms a full circle when viewed from above.

[0035] It has been found that by locating the electric cartridge below the inlet of the flow gap, trouble-free operation of the domestic water heating system according to the invention can be ensured. The electric cartridge can transfer more heat energy to the surrounding storage medium and is less likely to overheat.

[0036] According to a further embodiment, the multifunctional storage system comprises a further pump with a pumping direction opposite to that of the domestic hot water charging pump. Its pressure side is fluidically connected to the hot storage medium in the heating section of the storage tank and its suction side is fluidly connected to the inlet of the flow gap, which is also located in the upper heating section, i.e. the suction and pressure sides of the further pump are swapped compared to the domestic hot water charging pump during its normal operation described above. To distinguish it, this pump is referred to as a stratified charging pump. By means of the stratified charging pump, storage medium is pumped from the lower, colder section of the storage tank through the flow gap into the heating section and mixes with the storage medium there, which is additionally heated by an electric cartridge.This measure also serves to protect the e-cartridge, which is then surrounded by the storage medium when a predefined temperature limit is exceeded. This medium has a lower temperature than the storage medium in the heating area.

[0037] Alternatively or additionally, the suction side of the stratified charging pump can be fluidically connected directly to the lower section of the storage tank via a bypass line, and the bypass line can pump colder storage medium into the heating zone. Optionally, in this embodiment, the storage medium can also be introduced into the uppermost section of the storage tank or into a lower section of the heating zone.

[0038] The stratified charging pump can be arranged in series with the domestic hot water charging pump, in which case pumps capable of handling countercurrent flows are used. Otherwise, using one of the pumps arranged in series would result in the destruction of the second pump. Alternatively, both pumps can be configured as a single pump with reversible pumping direction.

[0039] To control the pumps, temperature sensors can be arranged in various suitable positions, for example in the upper and optionally lower area of ​​the storage tank as well as in the domestic water extraction or in other positions.

[0040] According to one embodiment, at least one further electric cartridge can be arranged in a deeper region of the storage tank, where the stratification has a significant temperature difference to both the uppermost and the lowermost layer, in particular in a middle section of the tank, for example in the buffer storage zone. A distance of more than one coil from the electric cartridge in the hot water charging zone, if there are several electric cartridges there below their lowest electric cartridge, is also advantageous. A distance of two, three, four, five or more coils is preferred, depending on the size of the storage tank and the number of coils, as well as its temperature stratification. The further, lower electric cartridge can be designed to be cascaded or operable separately from the first, i.e. the upper electric cartridge described above. For example, this electric cartridge can be operated in an energy range which lies above that of the upper electric cartridge.It can optionally be controlled in stages. The lower electric cartridge then heats a middle or lower layer of the storage tank, forming a base load. The upper electric cartridge can be switched on as needed, modulating the heat output depending on domestic hot water consumption. Optionally, the upper electric cartridge can also be switched off.

[0041] Such a cascaded arrangement with appropriately adjusted control ranges and cascaded operation is also possible when using more than two electronic cartridges arranged one above the other. The multiple electronic cartridges can be controlled individually or together, or even grouped together.

[0042] The control unit of the multifunctional storage system can be designed for automatic or manual control and regulation of the multifunctional storage system's processes, such as monitoring the temperature of the storage medium and the domestic water at various positions in and on the storage tank, as well as temperature regulation, establishing counterflow in the flow gap, determining the available PV surplus, and other, even subordinate, processes. In addition to the temperature sensors, the multifunctional storage system includes additional electronic components for this purpose, such as signal converters, flow switches for controlling the pumps, and others, as well as hydraulic components such as pumps, valves, buffer tanks for buffering potential pressure surges resulting from switching operations, and others.

[0043] The operation of one or more optionally several e-cartridges using the PV surplus as well as their control to optimize the self-consumption of solar power, the PV system linked to the heating system and the multifunctional storage can be carried out wirelessly on the basis of the temperature sensors.

[0044] In connection with the previously described embodiments of the multifunctional storage system, the problem is solved on the method side by its operation, whereby the E-cartridge is fed by that portion of solar energy from a PV system of the heating operator which cannot be used by the operator himself and would therefore have to be fed into the public electricity grid ("excess solar energy" or "PV surplus"), but can be effectively used with the method according to the invention for operating the domestic water heating.

[0045] The method according to the invention for operating the multifunctional storage system described above comprises the following features: In the storage tank, a stratified charge of the storage medium is created in the known manner, with the temperature of the storage medium decreasing from top to bottom, to form a buffer storage zone and a hot water charging zone above it. Furthermore, the domestic water is heated by means of the countercurrent domestic water heater in the multifunctional storage system. The domestic water is directed from bottom to top in the domestic water pipe and the storage medium of the storage tank is pumped through the flow gap from top to bottom, at least in the area of ​​the hot water charging zone, by means of the domestic water charging pump. This type of domestic water heating is also carried out according to the state of the art. An upper heating zone of the hot water charging zone, from which the storage medium is pumped into the flow gap, is heated by at least one electric cartridge.

[0046] The method according to the invention is based on the concept of heating the storage medium in the uppermost region of the storage tank, the heating zone described above, which is assigned to the hot water charging zone, by means of an electric cartridge arranged there, additionally and above the usual and required temperature for the storage medium, and pumping it into the inlet of the flow gap by means of the domestic water charging pump. In this way, the domestic water line is heated near its outlet from the storage tank to a level that is significantly higher than the temperature achievable by means of the regular temperature stratification of the storage medium in the storage tank due to the functionality of the multifunctional storage system described above. A reduction in the temperature stratification, at least in the buffer storage zone, can be avoided or is possible without allowing the temperature of the domestic water to drop below the temperature level.The timing of the heat source operation of the multifunctional storage system and the energy consumption of the heat source can be significantly reduced.

[0047] In one embodiment of the method according to the invention, the at least one electric cartridge is operated with electricity generated by an external photovoltaic system (PV system). Due to the use of energy from a photovoltaic system, preferably a PV system belonging to the operator of the multifunctional storage system, to operate the electric cartridge, the heat supply from the heat source to the entire storage medium can be further reduced. This is done in such a way that, despite the withdrawal of domestic water, the stratification is not only influenced to such a small extent that energy from the heat source is only required when larger quantities of domestic water are withdrawn. The quantity at which an energy supply from the heat source is required can also be influenced by the configuration and operation of the one or more electric cartridges.

[0048] According to the invention, the storage medium is heated in the upper area of ​​the hot water charging zone, which is the uppermost area in the storage tank and is also referred to here as the heating zone. It is pumped into the flow gap of the counterflow heat exchanger at the inlet located there, where it comes into direct thermal contact with the heat exchanger surface of the domestic water pipe. As a result, the domestic water, which flows through the heat exchanger in the opposite direction, from bottom to top, and has thus been preheated, is heated most intensively in the upper section of the heat exchanger.

[0049] The additional heat energy is supplied by one or more electric cartridges, with the electric cartridge generating electricity from the external PV system. According to one embodiment of the invention, this is the PV system of the operator of the multifunctional storage system, allowing its excess PV energy to be used for additional heating of the storage medium.

[0050] The electric cartridge operates within a power range that allows even low PV system outputs, particularly PV surplus, to be utilized. Currently, this range is up to five-digit wattage, but may change in the future with the further development of the heating and PV systems used. Depending on the design of the one or more electric cartridges, the optimal usable output can be achieved through control, for example, using pulse width modulation, or by adjusting at least one electric cartridge, or by connecting or disconnecting additional, existing electric cartridges. This is based on temperature measurements in the storage tank and / or the extracted domestic water.

[0051] To ensure optimal use of the available PV power, the invention uses an energy meter. This meter is communicatively connected to the electrical distribution board of the house in which the multifunctional storage system is installed and determines the currently available PV surplus from the PV system in use. The output of one or more e-cartridges is adjusted to this determined value.

[0052] When using multiple electric cartridges, further embodiments offer the option of combining the optionally variable power ranges of the electric cartridges. For example, the electric cartridges can be operated in multiple stages of the same or different power levels, or in cascading stages within the hot water charging zone or within the hot water charging zone and the buffer storage zone. The latter distribution of electric cartridges supports, for example, maintaining temperature stratification in the storage tank, as this can be influenced in the various situations described here for using the storage medium to adjust the temperature of the domestic water and the heating zone.

[0053] In the event that PV power is available to such an extent that the storage medium in the heating zone is heated to such an extent that its temperature exceeds a predefined target temperature that must not be exceeded, according to a further embodiment of the method, storage medium is pumped from a lower region of the storage tank, whose temperature is lower than the target temperature, into the heating zone by means of the stratification pump described above, at least until the temperature falls below said target temperature. The colder storage medium can optionally be supplied through the flow gap or through a bypass line, which can optionally run outside the storage tank independently of the temperature stratification. In a further embodiment, the colder storage medium can be pumped by the domestic hot water charging pump by connecting both pumps in series. A combination of both embodiments is also possible.

[0054] In the first case, storage medium is drawn from the lower area, where the outlet of the flow gap is located. This area is defined by the system and contains storage medium at a relatively low temperature, relative to the available temperature layers of the multifunctional storage system. The countercurrent flow in the flow gap is reversed to supply the colder storage medium. Due to the preferably unaffected or only slightly disturbed temperature stratification, the target temperature can be adjusted solely by the amount of storage medium supplied.

[0055] In the second case, the multifunctional storage system comprises one, optionally several, bypass lines, which lead inside or outside the storage tank from at least one colder area of ​​the storage medium located below the heating zone to the heating zone. The use of several bypass lines, each accessing different temperature layers, allows the temperature of the supplied storage medium to be varied.

[0056] A further advantage of the invention is the possibility of using existing

[0057] Retrofitting multifunctional storage systems with one or more e-cartridges for utilizing PV surpluses is also possible. Such integration of at least one e-cartridge apparently also includes its control, whereby the existing temperature and pressure sensors can be used for this purpose and, if necessary, supplemented with additional sensors. The integration is further supported by the available energy meters, which can be connected to the house's electrical distribution system and, depending on the available PV surplus, can control the e-cartridge(s) either wired or wirelessly.

[0058] In summary, the following advantages can be achieved with the multifunctional storage system according to the invention and its method of operation: The operating temperature for domestic water can be achieved without having to draw heat from the heat generator, for example, the heating system. However, at least the heat required for this purpose from the heating system can be significantly reduced. By configuring the number and position of the electric cartridges, their power ranges, and their control systems, the multifunctional storage system can be configured for a wide variety of demand quantities. In particular, the PV surplus of a PV system can be optimally utilized for domestic water heating. Disturbances in temperature stratification, at least in the buffer storage zone of the storage tank, can be prevented or at least significantly reduced in various ways. The components for implementing the process can be integrated into existing systems.

[0059] The invention will be explained in more detail below using exemplary embodiments. Those skilled in the art would expediently combine the features realized above and below in the various embodiments of the invention in further embodiments, as far as the respective requirements for the multifunctional storage system require and permit. The accompanying figures show in Fig. 1 a first embodiment of the multifunctional storage system with an electric cartridge in the heating area, and Fig. 2 a second embodiment of the multifunctional storage system according to Fig. 1 with another e-cartridge in the buffer storage zone.

[0060] The figures depict the invention only schematically and to the extent necessary for understanding the invention. They make no claim to completeness or scale. For example, the coils of the counterflow domestic water heater are shown enlarged, so the number of coils of the pipes and the positions of the electric cartridges between the coils that can be depicted are limited.

[0061] Fig. 1 shows a multifunctional storage system 1 with a storage container 2, which is filled with a storage medium 3. In the storage medium 3, a temperature stratification is created and maintained, with the temperature increasing from bottom to top. The temperature progression from low to higher temperatures is shown in Fig. 1represented by an increasing gray level of the area in the storage tank 2. By means of temperature stratification, a buffer storage zone 5 is created in the lower area and a hot water charging zone 6 in the area above it in the storage tank 2, whereby a sharp separation between the two zones is neither present nor required. The optional version with a perforated separating disc 9 is shown, which has an annular gap (not shown) surrounding the wall of the storage tank 2.

[0062] The countercurrent domestic water heater 10 is located in the interior of the storage tank 2 and, in the illustrated embodiment, runs through the buffer storage zone 5 and the hot water charging zone 6. This heater comprises a domestic water line 11 configured as a heat exchanger surface 11, whose domestic water outlet 13 opens out of the top of the storage tank 2, and whose domestic water inlet 12 is located at the base of the storage tank 2. Optionally, the countercurrent domestic water heater 10 can also be shortened by arranging the domestic water inlet 12 and the outlet 17 of the flow gap 15 higher than shown. Additionally or alternatively, the inlet 16 of the flow gap 15 can also have a different position. In the illustrated embodiment, this is located approximately half a turn of the domestic water line 11 below its upper passage through the wall 4. However, the countercurrent domestic water heater 10 runs at least through the hot water charging zone 6.

[0063] The counterflow domestic water heater 10 further comprises a flow line 14 concentrically enclosing the domestic water line 11. The flow line 14 is arranged over its entire length such that a flow gap 15 is formed between the two lines. The storage medium 3 is pumped from top to bottom through the flow gap 15 by means of a domestic water charging pump 18, the pressure side of which is connected to the upper end of the flow gap 15, whose inlet 16 is connected. The lower end of the flow gap 15 is therefore its outlet 17. In the exemplary embodiment, the pitch angle of the coils in the buffer storage zone 5 is selected to be greater than the pitch angle in the domestic water charging zone 6. Other ratios of the coils and / or the number of coils in both zones are possible.

[0064] In the illustrated embodiment, the inlet of the flow line 14 is located approximately half a turn below the domestic water outlet 13 from the storage tank 2. Other positions of the inlet 16 and outlet 17 of the flow gap 15 are possible depending on the length of the flow line 14.

[0065] Inlet 16 and outlet 17 of the flow gap 15 open into the storage medium 3. The domestic hot water charging pump 18 is arranged in a bypass line 27 that runs outside the storage tank 1. Its pressure side (the tip of the triangular symbol pointing towards the bypass line) is connected via the bypass line 27 to the inlet 16 of the flow gap 15, and its suction side (the opposite base of the triangular symbol) is connected to the uppermost end of the wall of the storage tank 2 via the same bypass line 27. The domestic hot water charging pump 18 pumps the hottest storage medium 3 located at the uppermost end of the storage tank 2 into the inlet 16 of the flow gap 14 to heat the domestic hot water to the required temperature.

[0066] The stratified charging pump 19 is arranged in series with the domestic hot water charging pump 18 in the same bypass line 27, but with the pumping direction reversed (represented by the oppositely directed pump symbol). It pumps colder storage medium 3 through the flow gap 15 from the lower area of ​​the buffer charging zone 5 into the uppermost part of the wall of the storage tank 2. An optional bypass line 27' (shown in dashed lines) leads from the pumps 18, 19 to an inlet into the buffer storage zone 5 located above the domestic hot water inlet 12.

[0067] In that section of the domestic water line 11 which is not surrounded by the flow line and is thus heated directly by the storage medium 3 in the storage tank 2, the inlet of the circulation line 8 protrudes so that its domestic water content is also heated.

[0068] A temperature sensor 22 is arranged in the upper area of ​​the storage tank 2 to measure the temperature of the storage medium 3. Additional temperature sensors at other positions are possible to support the, preferably automatic, control of the multifunctional storage system 1. Temperature sensors 22 in the buffer storage zone 5 and in the domestic water outlet 13 are shown merely as examples.

[0069] An E-cartridge 20.1 is arranged between the second coil 25 of the domestic water line 11 and the third coil 26 of the domestic water line 11, which is located at a distance from the first coil below it. Its rod-shaped heating surface extends between the two coils 25, 26. In the illustrated embodiment, E is greater than A, so that the E-cartridge 20.1 is arranged in the area of ​​the flow line 14. Other ratios of A and E to each other and, consequently, other positions between the coils are possible according to the above description.

[0070] To determine the position of the E-cartridge 20.1 and the inlet 16 of the flow gap 15 in the storage tank 2, both points are measured to the uppermost point of the inner wall of the storage tank 2 and can be related to each other on this basis. The distance from the inlet 16 of the flow gap 15 to the uppermost end of the tank wall of the storage tank 2 is designated A. The lowest point of the heating surface of the E-cartridge 20.1 to the same point on the upper wall is designated E. The distance E also determines the size of the "heating area" according to the above definition.

[0071] A control unit 21 automatically or manually controls and regulates the processes of the multifunctional storage system 1, such as temperature measurements, the operation of at least one electric cartridge 20.1, the operation of the pumps 18, 19, the determination of the PV surplus using an energy meter 23, and other, even subordinate, processes. To utilize the energy from the available PV system 24 and determine the PV surplus, the control unit 21 is communicatively connected to the PV system.

[0072] The multifunctional storage system according to Fig. 2 differs from that of the Fig. 1by an additional electric cartridge 20.2, which is located in the buffer storage zone 5 and heats the temperature layer located there to form a base load. In this embodiment, the additional electric cartridge 20.2 is located between the third and fourth coils of the domestic water line 11. Here, too, other positions and / or multiple electric cartridges within the buffer storage zone 5 are possible.

[0073] Furthermore, the buffer storage zone 5 and the hot water charging zone 6 are not separated by a partition. For further information, please refer to the explanations for Fig. 1 referred to. List of reference symbols

[0074] 1 Multifunctional storage system 2 Storage tank 3 Storage medium 4 Wall 5 Buffer storage zone 6 Hot water charging zone 7 Heating zone 8 Circulation line 9 Separating disc 10 Counterflow domestic water heater 11 Domestic water line, heat exchanger surface 12 Domestic water inlet 13 Domestic water outlet 14 Flow line 15 Flow gap 16 Flow gap inlet 15 17 Flow gap outlet 15 18 Domestic water charging pump 19 Stratified charging pump 20.1; 20.2 Electric cartridge, E-cartridge 21 Control unit 22 Temperature sensor 23 Energy meter 24 PV system 25 Second coil of the domestic water line 11 26 Third coil of the domestic water line 11 27, 27' Bypass line ADistance top wall - bottom edge of inlet flow gap EDistance top wall - bottom edge of heating surface E-cartridge 2024023566 2024-09-09

Claims

1. Multifunctional storage system designed to generate heat for the purpose of space heating by storing heat in a heat-carrying storage medium heated by an external heat source and for domestic hot water heating, comprising the following components: - a multi-zone stratified storage tank with a storage container (2) for receiving the storage medium (3), - wherein the multi-zone stratified storage tank comprises devices for forming a stratified charge generated by different temperatures of the storage medium (3) in such a way that a hot water charging zone (6) is formed above a buffer storage zone (5), in such a way that the temperature of the storage medium (3) increases with increasing height in the storage container (2);- a countercurrent domestic water heater (10) which runs at least partially through the hot water charging zone (6), - wherein the countercurrent domestic water heater (10) has a domestic water line (11) designed as a heat exchanger surface, the domestic water outlet (13) of which is located above the domestic water inlet (12), - and a flow line (14) which concentrically surrounds the domestic water line (11) in such a way that a flow gap (15) is formed between the two lines, - wherein the upper inlet (16) and the lower outlet (17) of the flow gap (15) located thereunder openly open into the storage medium (3) and the inlet (16) of the flow gap (15) has a distance A from the upper wall (4) of the storage tank (2);- a domestic water charging pump (18), designed to charge the flow gap (15) with storage medium, the suction side of which is fluidically connected to the upper region of the volume of the storage tank (2) located above the inlet (16) of the flow gap (15) and the pressure side of which is fluidically connected to the inlet (16) of the flow gap (15), - a control unit (21), designed and configured to operate the multifunctional storage system (1); ; characterized in that : - the multifunctional storage system (1) comprises at least one electric cartridge (20.1), here also referred to as E-cartridge for short, the heating surface of which is arranged in an upper heating area within the hot water charging zone (6), at a distance E, measured from the uppermost end of the wall (4) of the storage tank (2) to the lower edge of the heating surface of the E-cartridge (20.1), - wherein the heating area extends at most up to the eighth coil of the domestic water pipe 11.

2. Multifunctional storage system according to claim 1, characterized in that the control unit (21) is designed and configured to operate the at least one e-cartridge (20.1) using the energy of an external photovoltaic system (24).

3. Multifunctional storage system according to claim 2, characterized in that the control unit (21) of the multifunctional storage system (1) comprises an energy meter (23) which is designed to determine a PV surplus available from an external PV system (24) and to adapt the power of the at least one e-cartridge (20.1) to the determined PV surplus.

4. Multifunctional storage system according to one of the preceding claims, characterized in that the distance E is greater than the distance A.

5. Multifunctional storage system according to one of the preceding claims, further comprising a stratified charging pump (19), the pressure side of which is fluidically connected to the upper region of the volume of the storage container (2) and the suction side of which is fluidically connected to the inlet (16) of the flow gap (15) and / or the buffer storage zone (5).

6. Multifunctional storage system according to claim 5, characterized in that the domestic hot water charging pump (18) and the stratified charging pump (19) are connected in series.

7. Multifunctional storage system according to one of the preceding claims, characterized in that the multifunctional storage system (1) has at least one further e-cartridge (20.2) which is arranged in the buffer storage zone (5).

8. A method for operating a multifunctional storage system according to one of the preceding claims, - wherein a stratified charge of the storage medium (3) is generated in the storage tank (2), with the temperature of the storage medium (3) decreasing from top to bottom, to form a buffer storage zone (5) and an overlying hot water charging zone (6), - wherein the domestic water is heated by means of the countercurrent domestic water heater (11) in the multifunctional storage system (1) by directing the domestic water in the domestic water line (11) from bottom to top and pumping the storage medium (3) of the storage tank (2) through the flow gap (15) from the upper inlet (16) to the lower outlet (17) of the flow gap (15) by means of the domestic water charging pump (18), characterized in that said upper heating area of the hot water charging zone (6), from which the storage medium (3) is pumped into the flow gap (15), is heated by means of at least one electric cartridge (20.1).

9. A method for operating a multifunctional storage system according to claim 8, characterized in that the at least one e-cartridge (20.1) is operated with the electricity, preferably with the PV surplus, which is generated by an external photovoltaic system (PV system) (24).

10. A method for operating a multifunctional storage system according to claim 9, characterized in that by means of an energy meter (23) a PV surplus available from the external PV system (24) is determined and the power of the at least one e-cartridge (20.1) is adjusted to the determined PV surplus.

11. A method for operating a multifunctional storage system according to one of claims 8 to 10, characterized in that several electric cartridges (20.1, 20.2) are operated in several stages of equal output or in cascading stages within the hot water charging zone (6) or within the hot water charging zone (6) and the buffer storage zone (5).

12. Method for operating a multifunctional storage system according to claims 8 to 11, characterized in that by means of the stratified charging pump (19) storage medium (3) is pumped from the inlet (16) of the flow gap (15) and / or from the buffer storage zone (5) of the storage tank (2) into the heating area.

13. A method for operating a multifunctional storage system according to claim 12, characterized in that said storage medium (3) is pumped through the domestic hot water charging pump (18).

14. A method for operating a multifunctional storage system according to one of claims 8 to 14, characterized in that at least one electric cartridge (20.1) is integrated into the hot water charging zone of an existing multifunctional storage system (1).

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