EP4521036A1 - Bivalent multifunction storage system - Google Patents

Abstract

The invention relates to a multifunctional storage system 1 for generating heat and domestic water heating. The system comprises a multi-zone stratified storage tank with a buffer storage zone 5 and a hot water charging zone 6 located above it, a countercurrent domestic water heater 10 with a domestic water line 11 and a flow line 14 arranged such that a flow gap 15 exists between the two, a domestic water charging pump 18 for charging the flow gap 15 with the storage medium 3, a control unit 21 for operating the multifunctional storage system 1, and an electric cartridge 20.1, the heating surface of which is arranged within the hot water charging zone 6, the heating area extending up to the eighth coil of the domestic water line 11. The invention also relates to a method for operating the multifunctional storage system 1. (Fig. 1)

Description

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.

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 supply 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.

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, for example a heat pump, in such a way that the storage tank always contains a stratified charge 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 or perforated discs, with an outer annular gap, flow guide devices and other fittings in the storage tank are used. If the hot water charging zone is not separated by a perforated disc of the buffer storage zone, the expert can also identify the two zones of the multi-zone stratified storage system using other features, for example the density and gradient of the coils or the temperature distribution in the storage medium.

A counterflow domestic water heater is usually 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 design of the line's surface, to ensure effective heat transfer to the domestic water flowing in the line.

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 the counterflow, the domestic water flow runs from bottom to top, and the storage medium flow in the flow gap 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 further comprises measuring sensors and a circulation line, with the circulation line flowing into the domestic water line at the return connection. The amount of flowing water in the circuit depends directly on the heat input by the Storage medium, whereby the temperature stratification in the storage medium should be maintained as far as possible.

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.

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.

A multi-zone stratified storage tank with buffer storage and integrated hot water preparation is available from the DE 10 2010 028 198 A1 Such a heating system has a heat pump as a heat source for heating the storage medium in the storage tank. The storage medium has a temperature stratification, which 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 on the flow-countercurrent principle and comprises a tubular, usually coiled domestic water pipe, which is designed as a heat exchanger surface and is made of a corrosion-resistant material. The domestic water pipe is surrounded by a flexible, temperature- and pressure-resistant flow line in such a way that an annular A flow gap is created. The flow gap opens at least at the top, in this design open on both sides into the buffer tank, with a distance to the top and bottom walls of the storage tank so that the storage medium can flow through the flow gap using a charging pump that pushes from above or alternatively sucks from below and comes into thermal contact with the domestic water pipe. If the lower end of the flow gap does not open into the buffer tank in alternative designs, then it is fluidly connected to the lower area of the storage volume, for example by means of a pipe loop ( DE 298 16 006 U1 , DE 10 2009 026 420 A1 ).

In the multi-zone stratified storage system of the 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 here. The refrigerant is fed through the storage tank via a coiled pipe and heats 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 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.

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.

Such multifunctional storage systems are increasingly bivalent. The term bivalent is understood in energy generation to mean that two different heat energy generators are combined to heat the heating and/or domestic water.

The known bivalent solutions, whenever 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, each 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.

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

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 may also be used. The heating coil may have a heat-conducting sheath. A wide variety of designs are known to those skilled in the field of heating technology.

In order to generate the energy required to heat the storage medium, numerous electric cartridges are sometimes integrated, which operate at different power levels depending on the respective heat energy demand and are integrated into the buffer storage layer corresponding to their power. Although such a solution allows, especially in warm During the warmer and lightier seasons, the energy required by the heating system is reduced and replaced with solar energy. However, this solution has a negative impact on efficiency due to the technical complexity of the heating cartridges and their control system, as well as the associated impact on the stratification in the storage tank.

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.

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 himself.

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.

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.

• einen Mehrzonen-Schichtladespeicher mit einen Speicherbehälter zur Aufnahme des Speichermediums,
• wobei der Mehrzonen-Schichtladespeicher Vorrichtungen umfasst zur Ausbildung einer durch unterschiedliche Temperaturen des Speichermediums erzeugten Schichtladung derart, dass über einer Pufferspeicherzone eine darüber liegende Warmwasserladungszone ausgebildet ist, derart dass die Temperatur des Speichermediums mit zunehmender Höhe im Speicherbehälter zunimmt;
• einen Gegenstrom-Brauchwassererhitzer, welcher zumindest abschnittsweise durch die Warmwasserladungszone verläuft,
• wobei der Gegenstrom-Brauchwassererhitzer eine als Wärmetauscherfläche ausgebildete Brauchwasserleitung aufweist, deren Brauchwasserausgang oberhalb deren Brauchwassereingangs liegt,
• sowie eine die Brauchwasserleitung konzentrisch umhüllende Strömungsleitung derart, dass zwischen beiden Leitungen ein Strömungsspalt ausgebildet ist,
• wobei der obere Eingang und der darunter liegende untere Ausgang des Strömungsspalts offen im Speichermedium münden;
• wobei der Eingang des Strömungsspaltes eine Abstand A zum obersten inneren Abschluss der Behälterwandung aufweist;
• eine Brauchwasserladepumpe, ausgebildet zur Beladung des Strömungsspaltes mit Speichermedium, deren Saugseite mit dem über dem Eingang des Strömungsspaltes liegenden, oberen Bereich des Volumens des Speicherbehälters und deren Druckseite mit dem Eingang des Strömungsspalts fluidisch verbunden ist,
• eine Steuereinheit, ausgebildet und konfiguriert zum Betreiben des Multifunktionsspeichersystems,
• zumindest eine Elektropatrone, hier verkürzt auch als E-Patrone bezeichnet, deren Heizfläche zur Erwärmung des Speichermediums in einem Heizbereich innerhalb der Warmwasserladezone angeordnet ist, mit einem Abstand E, gemessen vom obersten inneren Abschluss der Behälterwandung des Speicherbehälters bis zur Unterkante der Heizfläche der E-Patrone,
• wobei sich der Heizbereich maximal bis zur achten Wendelung der Brauchwasserleitung erstreckt.

The object is achieved by the subject matter of claim 1, wherein the multifunctional storage system comprises the following components includes:

• a multi-zone stratified storage tank with a storage container for the storage medium,
• wherein the multi-zone stratified charging 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 tank;
• a countercurrent domestic water heater, which runs at least partially through the hot water charging zone,
• wherein the countercurrent domestic water heater has a domestic water pipe designed as a heat exchanger surface, the domestic water outlet of which is located above its domestic water inlet,
• and a flow line concentrically surrounding the domestic water line in such a way that a flow gap is formed between the two lines,
• wherein the upper inlet and the lower outlet of the flow gap open into the storage medium;
• wherein the inlet of the flow gap has a distance A from the uppermost inner end of the container wall;
• a domestic water charging pump, designed to charge the flow gap with storage medium, the suction side of which is fluidically connected to the upper area of the storage tank volume 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, here also referred to as E-cartridge, whose heating surface for heating the storage medium is arranged in a heating area within the hot water charging zone, with a distance E, measured from the uppermost inner end of the Tank wall of the storage tank up to the lower edge of the heating surface of the electric cartridge,
• The heating area extends up to a maximum of the eighth coil of the domestic water pipe.

As multifunctional memory according to the invention, various known memory types can be used. DE 10 2010 028 198 A1 As described above in the prior art, a buffer storage is known. 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. Reference is made to both applications in their entirety here.

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.

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, and thus the additional energy from the electric cartridge is used primarily for domestic water heating.

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 through a specially designed opening in the wall of the storage tank into the storage medium.

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.

According to the invention, the heating area extends up to the eighth coil of the domestic water pipe, optionally up to the seventh, sixth, fifth, fourth, third, or second coil. The coils of the domestic water pipe 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.

The 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 that is actually influenced by the one or more electric cartridges in the hot water charging zone. If the defined lower end of the hot area is of little or no importance for the aspect being described, this area in question is also referred to below as the "hot area".

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.

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 water line (counting from the top), and within the hot water charging zone, the domestic 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.

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., a system 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.

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 PV surplus, for domestic water heating. Depending on the size of the storage tank, the extent of regular domestic water withdrawal, 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 steps 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.

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.

For example, the control unit includes an energy meter or is communicatively connected to one. An energy meter serves and is designed and configured to measure the energy available from the PV system. Determine energy surplus based on comparison with the preset feed-in energy. The energy meter can also be designed to implement the communicating connection between the electric cartridge and the external PV system. It controls or regulates the at least one or more electric cartridges depending on the required output 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 to control it, so that the output of the electric cartridge can be adjusted to the available and measured PV surplus. The energy meter can also be configured to receive measured values from the electric 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.

The arrangement of at least one or more electric cartridges in the heating area 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 coil, 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 line that forms a full circle in a plan view.

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.

According to a further embodiment, the multifunctional storage system comprises an additional 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 connected to the inlet of the flow gap, which is also located in the upper heating section. This means that the suction and pressure sides of the additional pump are reversed 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. The stratified charging pump pumps storage medium from the lower, colder section of the storage tank through the flow gap into the heating section, where it mixes with the storage medium there, which is additionally heated by the electric cartridge. This measure also serves to protect the electric cartridge, which is consequently surrounded by storage medium when a predefined limit temperature is exceeded. This storage medium has a lower temperature than the storage medium in the heating section.

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.

The stratified charging pump can be arranged in series with the domestic hot water charging pump, in which case pumps are used which can handle counter-rotating flows. Otherwise, the use of one of the pumps arranged in series would result in the destruction of the second pump. Alternatively, both pumps can be configured as one pump with reversible pumping direction.

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.

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 lowermost layers, particularly in a central 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 multiple 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 that lies above that of the upper electric cartridge. It can optionally be step-controlled. 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.

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

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.

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.

In connection with the previously described embodiments of the multifunctional storage system, the problem is solved in terms of the method 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.

• Im Speicherbehälter wird in der bekannten Weise eine Schichtladung des Speichermediums erzeugt, mit von oben nach unten abnehmender Temperatur des Speichermediums, zur Ausbildung einer Pufferspeicherzone und einer darüber liegenden Warmwasserladungszone.
• Weiter wird das Brauchwasser mittels des Gegenstrom-Brauchwassererhitzers im Multifunktionsspeichersystem erhitzt, indem das Brauchwasser in der Brauchwasserleitung von unten nach oben geleitet wird und das Speichermedium des Speicherbehälters durch den Strömungsspalt von oben nach unten, zumindest im Bereich der Warmwasserladezone, mittels der Brauchwasserladepumpe gepumpt werden. Auch eine solche Brauchwassererwärmung erfolgt gemäß Stand der Technik.
• Ein oberer Heizbereich der Warmwasserladezone, aus welchem das Speichermedium in den Strömungsspalt gepumpt wird, wird mittels zumindest einer E-Patrone beheizt.

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 generated 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 the counterflow 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 by the domestic water charging pump, at least in the area of the hot water charging zone. This type of domestic water heating is also carried out according to the state of the art.
• An upper heating area 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.

The method according to the invention is based on the concept of heating the storage medium in the uppermost area of the storage tank, the heating area 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 fall below the temperature level. The timing of the operation of the Heat source of the multifunctional storage system and the energy requirement of the heat source can be significantly reduced.

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 amount 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.

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.

The additional heat energy is supplied via one or more electric cartridges, which generate 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.

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 tapped domestic water.

To ensure optimal use of the available PV power, the invention utilizes 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.

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.

In the event that PV power is available to such an extent that the storage medium in the heating area is heated to such an extent that its temperature If the 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, the temperature of which is lower than the target temperature, into the heating zone by means of the stratified charging 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.

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 counterflow 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.

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 area to the heating area. The use of several bypass lines, each accessing different temperature layers, allows the temperature of the supplied storage medium to be varied.

A further advantage of the invention is the possibility of using existing

Retrofitting multifunctional storage systems with one or more e-cartridges for utilizing the PV surplus is possible. Such integration of at least one e-cartridge also apparently 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 power distribution system and, depending on the available PV surplus, can control the e-cartridge(s) via wired or wireless connection.

• Die Betriebstemperatur für Brauchwasser kann erzielt werden, ohne dafür Wärme vom Wärmeerzeuger, beispielsweise von der Heizungsanlage beziehen zu müssen. Zumindest jedoch kann die von der Heizungsanlage dafür zu liefernde Wärme signifikant reduziert werden.
• Mittels der Konfiguration hinsichtlich Anzahl und Lage der E-Patronen, deren Leistungsbereiche und Regelungen kann das Multifunktionsspeichersystem für verschiedenste Bedarfsmengen konfiguriert werden.
• Es kann insbesondere der PV-Überschuss einer PV-Anlage optimal für die Brauchwassererwärmung genutzt werden.
• Eine Störung der Temperaturschichtung zumindest in der Pufferspeicherzone des Speicherbehälters kann auf verschiedene Weisen verhindert oder zumindest signifikant reduziert werden.
• Die Komponenten zur Ausführung des Verfahrens sind in bestehende Anlagen integrierbar.

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 a heat generator, such as the heating system. However, the heat required for this purpose from the heating system can at least be significantly reduced.
• By configuring the number and position of the e-cartridges, their performance ranges and controls, the multifunctional storage system can be configured for a wide range of required quantities.
• In particular, the PV surplus of a PV system can be optimally used for domestic water heating.
• A disturbance of the 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 carrying out the process can be integrated into existing systems.

• Fig. 1 eine erste Ausführungsform des Multifunktionsspeichersystems mit einer E-Patrone im Heizbereich, und
• Fig. 2 eine zweite Ausführungsform des Multifunktionsspeichersystems gemäß Fig. 1 mit einer weiteren E-Patrone in der Pufferspeicherzone.

The invention will be explained in more detail below with reference to exemplary embodiments. The person skilled in the art would recognize the features realized above and below in the various embodiments of the invention in further The embodiments can be combined as required and permitted by the respective requirements for the multifunctional storage system. The accompanying figures show

• 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.

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 that the number of coils of the pipes and the positions of the electric cartridges between the coils that can be depicted are limited.

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. 1 represented 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.

In the interior of the storage tank 2, in the illustrated embodiment by the buffer storage zone 5 and the A countercurrent domestic water heater 10 is formed running through the hot water charging zone 6. This comprises a domestic water line 11 designed as a heat exchanger surface 11, the domestic water outlet 13 of which opens out of the top of the storage tank 2, and the domestic water inlet 12 of which 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.

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.

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.

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.

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.

In that section of the domestic water pipe 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 pipe 8 protrudes so that its domestic water content is also heated.

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.

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. The E-cartridge's 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 one another and, consequently, other positions between the coils are possible according to the above description.

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.

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.

The multifunctional storage system according to Fig. 2 differs from that of the Fig. 1 by a further E-cartridge 20.2, which is arranged in the buffer storage zone 5 and uses the temperature layer located there to form a Base load heating. In this embodiment, the additional electric cartridge 20.2 is located between the third and fourth coils of the domestic hot water line 11. Other positions and/or multiple electric cartridges within the buffer storage zone 5 are also possible.

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

1

Multifunctional storage system

2

storage tank

3

Storage medium

4

wall

5

Buffer storage zone

6

Hot water charging zone

7

Heating area

8

circulation line

9

cutting disc

10

Counterflow domestic water heater

11

Domestic water pipe, heat exchanger surface

12

Domestic water inlet

13

Domestic water outlet

14

Flow line

15

flow gap

16

Entrance of the flow gap 15

17

Exit of the flow gap 15

18

Domestic hot 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 pipe 11

26

third coil of the domestic water pipe 11

27, 27'

Bypass line

A

Distance top wall - bottom edge inlet flow gap

E

Distance top wall - bottom edge of heating surface of electric cartridge 2024023566 2024-09-09

Claims (14)

Multifunctional storage system designed to generate heat for 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 holding the storage medium (3), - wherein the multi-zone stratified charging 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 tank (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 pipe (11) designed as a heat exchanger surface, the domestic water outlet (13) of which is located above its domestic water inlet (12), - and a flow line (14) concentrically surrounding the service water line (11) such 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 open into the storage medium (3) and the inlet (16) of the flow gap (15) is at a distance A from the upper wall (4) of the storage container (2); - a domestic water charging pump (18), designed to charge the flow gap (15) with storage medium, the suction side of which is 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 connected to the inlet (16) of the flow gap (15) is fluidically connected, - 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), - whereby the heating area extends up to the eighth coil of the domestic water pipe 11. 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). 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. Multifunctional storage system according to one of the preceding claims, characterized in that the distance E is greater than the distance A. 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). Multifunctional storage system according to claim 5, characterized in that that the domestic hot water charging pump (18) and the stratified charging pump (19) are connected in series. 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). 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 a hot water charging zone (6) above it, - 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 pipe (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). 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 current, preferably with the PV surplus, which is generated by an external photovoltaic system (PV system) (24). 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. Method for operating a multifunctional storage system according to one of claims 8 to 10, characterized in that several E-cartridges (20.1, 20.2) are operated in several stages of equal power 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). 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 container (2) into the heating area. Method for operating a multifunctional storage system according to claim 12, characterized in that said storage medium (3) is pumped through the domestic water charging pump (18). Method for operating a multifunctional storage system according to one of claims 8 to 14, characterized in that the 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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