Latent heat storage device, energy supply system with at least one latent heat storage device and method for operating an energy supply system with at least one latent heat storage device

Abstract

The invention relates to a latent heat storage system (100), an energy supply system, and a method for its operation to provide heat and cold to a consumer, comprising a storage container (10) for receiving a storage medium (12) in an interior space (14) and a heat exchanger unit (40) arranged therein, which is supplied with a heat transfer fluid (52) during operation. The heat exchanger unit (40) has heat exchanger plates (60) which are designed as at least one compact module (50), wherein the heat exchanger plates (60) of the at least one module (50) are spaced apart from each other at a first predetermined distance (62) transversely to a vertical axis (110) of the storage container (10).The at least one module (50) is arranged with its heat exchanger plates (60) spaced apart from the bottom (16) and the wall (18) of the container, wherein the at least one module (50) with its heat exchanger plates (60) occupies at most half of a target level (20) of the storage medium (12) in the interior (14) along the vertical axis (110).

Description

The invention relates State of the art

[0001] Latent heat storage systems for storing sensible and latent heat are particularly well-known in the form of ice storage systems. One problem with such ice storage systems is that the storage medium, water, freezes and expands when heat is extracted. This poses the risk of damaging or even destroying the storage tank as well as any heat exchangers located within the storage medium. Furthermore, ice formation impedes the thermal exchange between the storage medium and the heat exchanger.

[0002] From EP 1 807 672 B1, an energy supply system is known with a latent heat storage system surrounded by earth and a central extraction heat exchanger, which can be cooled in a directed direction from the inside out during the extraction phase, so that the storage medium forms an ice monolith around the extraction heat exchanger. During the regeneration phase, the ice monolith is thawed in a directed direction from the outside in.

[0003] From DE 30 23 592 A1, a latent heat storage system in the form of an ice storage unit with a thermally insulated storage tank in a building basement is known. The bottom of the ice storage unit is covered with a flat heat exchanger in the form of a ribbed sheet, to which pipes for a cooling device and a hot water circulation system are arranged. During a withdrawal period, ice is continuously formed in depressions of the heat exchanger and removed by means of the hot water circulation.

[0004] EP 0 019 235 A1 discloses a latent heat storage system in the form of an ice storage system, the bottom of which forms the evaporator of a heat pump. The ice that forms on the evaporator is periodically defrosted by supplying heat from an external heat source or by switching the heat pump.

[0005] From DE 31 36 614 A1, a latent heat storage system in the form of an ice storage unit is known, which has a cooling plate on the bottom of the storage container connected to a heat pump. The ice layer that forms on the cooling plate during heat extraction is defrosted by a brief supply of heat, thus enabling heat extraction via the cooling plate again. The heat extraction can be set periodically. A thermostat control oversees the time period, which terminates the defrosting process when a specific outlet temperature of the heat transfer fluid is reached and switches back to heat extraction. During the defrosting of the ice layer, the brine outlet temperature is measured. If the brine outlet temperature falls below the setpoint, either hot gas defrosting occurs or the heat pump is switched off entirely, and warm brine from a heat storage unit is supplied to the cooling plate.

[0006] From CH 713 882 B1, a latent heat storage system, comprising the features of the preamble of claim 1, is known in the form of an ice storage system in which individual plate heat exchangers are arranged along the vertical axis at the bottom of the storage container. The connections for supplying and discharging the heat transfer fluid are located on the side edges of the plates, which are separated from the plate surface by a barrier structure. The plate heat exchangers are completely immersed in water, and the barrier structures prevent the ice sheets forming on the plate surfaces from growing into areas located below the supply and discharge connections when viewed in the direction of gravity. Likewise, a positive connection with the forming ice sheets is prevented, which further facilitates the removal of the ice.

[0007] EP 0 004 552 A1 discloses a latent heat storage system in the form of an ice storage system with vertically arranged lamellae in the storage container. Ice sheets can form on both sides of the lamellae, growing together at their free ends. Heat is supplied to the lamellae to detach them. For heat extraction, an evaporator tube is arranged at the base of each lamella. This tube forms part of the evaporator of a heat pump and is filled with a refrigerant, e.g., a fluorocarbon. A conduit through which a heat transfer fluid flows is also arranged at the base of the lamellae. Undesirable encirclement of the lamellae's lateral edges by the forming ice is prevented by the individual lamellae projecting into the side walls of the storage container with their lateral edge regions.The storage tank and the fins are dimensionally matched in such a way that, with maximum heat extraction and minimal heat input (just sufficient to detach the ice from the fins), a sufficiently large volume of water is available above the fins to absorb the ice floating in the water.

[0008] From CA 3 109 464 C, a storage device is known in which ice blocks are stored in a storage tank for cooling purposes. The storage tank is thermally insulated from the outside. Inside the storage tank, a cooling element in the form of a flattened coiled tube is positioned in the bottom area and is provided on both sides with an electrically conductive plate. Ice can form on the plate when heat is removed. The plate is equipped with electrical contacts. To detach the ice, the plate can be energized, causing it to heat up and the ice to melt. The ice floats to the surface of the storage tank and can be removed from there as needed. The water level in the tank is monitored to determine the amount of ice available. Disclosure of the invention

[0009] One objective of the invention is to provide a latent heat storage device that is easy to manufacture.

[0010] Another object of the invention is to provide a manufacturing-friendly energy supply system that includes at least one latent heat storage device.

[0011] Another object of the invention is to provide a method for operating such an energy supply system.

[0012] The problems are solved by the features of the independent claims. Favorable embodiments and advantages of the invention become apparent from the further claims, the description, and the drawings.

[0013] According to one aspect of the invention, a latent heat storage system for providing heat and cold to a consumer is proposed, comprising a storage container for holding a storage medium in an interior space and a heat exchanger unit arranged therein, which is in thermal contact with the storage medium and through which a heat transfer fluid flows during operation. The heat exchanger unit has heat exchanger plates, each of which is through which the heat transfer fluid flows. The heat exchanger plates of the heat exchanger unit form at least one compact module. The heat exchanger plates of the at least one module are spaced apart from each other transversely to a vertical axis of the storage container at a first predetermined distance. The at least one module is spaced apart with its heat exchanger plates from the bottom and the wall of the container.At least one module, with its heat exchanger plates along the vertical axis, occupies at most half of the target level of the storage medium inside the storage tank.

[0014] A latent heat storage system is a component of an energy supply system for providing a consumer with thermal energy, especially heat and cold. The storage medium can be, in particular, water.

[0015] By changing the distances between the heat exchanger plates and the thickness of the ice plates, an energy supply system with such a latent heat storage system can be designed and used as a long-term or short-term / high-performance storage system.

[0016] The latent heat storage system is preferably dimensioned to supply a consumer in the form of a residential building, in particular a single-family or two-family house, with heat in winter and cooling in summer. Advantageously, the latent heat storage system works in conjunction with a heat pump in an energy supply system, which receives the heat transfer fluid from the heat exchanger unit on its primary side.

[0017] With this arrangement of the heat exchanger plates, no buoyancy forces act on the storage tank or, as in other cases, on a conventional mounting system that supports the extraction heat exchanger. The buoyancy forces that arise at the heat exchanger unit itself are counteracted by the unit's own weight.

[0018] The heat exchanger unit with one or more modules with heat exchanger plates can optionally also be used for a regeneration system as an absorber, energy fence, etc.

[0019] Advantageously, the storage tank is located underground. Ideally, the latent heat storage unit is in thermal contact with the surrounding soil.

[0020] The heat exchanger unit can be fixed to the ground in such a way that a gap of 15-20 cm remains between the base plate and the underside of the heat exchanger unit. This space can be used for routing pipes and cables. Furthermore, this ensures that the ground beneath the storage tank does not freeze and that any temporarily present water does not freeze, thus preventing it from exerting any stress on the storage tank. Advantageously, the storage tank can be pre-equipped with the heat exchanger unit by the manufacturer, i.e., pre-assembled. Industrial manufacturing of the heat exchanger unit ensures the required quality and reduces time-consuming and expensive on-site labor. It also reduces on-site installation time.

[0021] The modular design of the heat exchanger unit allows the storage tank to be equipped with a heat exchanger unit comprising one, two, or more modules, as needed. The number of modules can be adjusted according to the expected energy demand of the consumer and the conditions at the installation site. The pre-assembled storage tank can be designed for road transport and is therefore easy to transport to the consumer. Only a pit for the storage tank needs to be provided. Extensive construction work, such as casting the storage tank on site, labor-intensive installation of the extraction heat exchanger, and similar tasks, is eliminated. The storage tank can be filled with the storage medium, for example, water, on site.The heat transfer fluid can also be filled into the heat exchanger unit on site, or this can be done during installation in the storage tank.

[0022] Damage to the storage tank during operation due to icing can be avoided. If a defect occurs in the latent heat storage unit, it can be easily replaced as a complete unit.

[0023] The heat exchanger plates can be made of aluminum, stainless steel, or plastic (PE). The heat exchanger unit and all pipes are preferably filled with a glycol / water mixture, also known as brine.

[0024] It is advantageous to insulate the inlet and outlet pipes to the heat exchanger plates. This prevents uncontrolled ice build-up above the heat exchanger unit inside the storage tank.

[0025] Compared to previous heat exchanger systems, the modular design of the heat exchanger unit offers several advantages: the possibility of industrial prefabrication and the associated quality assurance, as well as reduced material usage and assembly costs. The use of self-contained modules for the heat exchanger unit simplifies the simulation and design process for energy supply systems with such latent heat storage devices at the manufacturer's site.

[0026] Advantageously, the energy supply system can be used worldwide for climate-friendly heating and cooling applications, regardless of years of experience.

[0027] According to the invention, the heat exchanger plates, with their end faces intended to face the bottom of the container, are arranged on a pallet, in particular a plastic pallet, similar to a so-called Euro pallet. The pallet can be welded to the heat exchanger plates or otherwise securely attached, thus forming a stable module that is therefore transportable and storable.

[0028] In a well-designed latent heat storage system, at least one module can have a distribution line and a collection line. Specifically, the fluid inlets of the heat exchanger plates can lead into the distribution line, and the fluid outlets of the heat exchanger plates can lead into the collection line for the heat transfer fluid. The heat exchanger plates can also be connected in parallel. If two or more modules are to be installed in the latent heat storage system, they can simply be connected via their distribution and collection lines.

[0029] With a favorable design of the latent heat storage system, distribution and collection lines of several, especially identical, modules can be interconnected within the storage tank, particularly in parallel. The number of modules can be easily increased as needed.

[0030] With a favorable design of the latent heat storage system, at least one module with its heat exchanger plates can occupy a maximum of one-third of the target level of the storage medium along its vertical axis. Advantageously, the free volume of the storage medium in the storage tank above the heat exchanger unit can accommodate those ice slabs that are detached from the heat exchanger unit and float to the top of the storage tank. No pressure is exerted on the storage tank by the floating ice, thus advantageously avoiding any risk of damage from ice formation.

[0031] According to a favorable design of the latent heat storage system, at least one module with its heat exchanger plates can have an area for heat extraction of at least 2 m², in particular up to 2.5 m².

[0032] Suitable dimensions for heat exchanger plates can be, for example, approximately 800 mm to 1200 mm wide and up to 1200 mm high. Each plate then has a surface area of ​​approximately 2 to 2.5 m², including the front and back surfaces. A module of a heat exchanger unit can ideally consist of 8 to 12 heat exchanger plates.

[0033] One module of a heat exchanger unit with these dimensions is sufficient to supply a detached house with approximately 150 m² of heated floor space, for example in Central Europe, providing it with heat and, if necessary, cooling throughout the year. Should more capacity be required, the output of the heat exchanger unit can be increased by installing and connecting additional modules.

[0034] In a favorable design of the latent heat storage system, the module with its heat exchanger plates can have an enclosing shell with a volume of at most 20%, preferably 15%, particularly preferably at most 10% of the volume of the storage medium. The module can, for example, be cuboid in shape, so that the shell is also a cuboid.

[0035] Because the heat exchanger unit is installed in the lower part of the storage tank and occupies only a small volume, the space above the unit can be used as an "ice storage area" for the ice flakes that float to the surface. The storage tank and the heat exchanger unit do not have to withstand any significant mechanical forces and can therefore be provided simply and inexpensively. Defrosting the surfaces of the heat exchanger plates keeps the heat extraction capacity of the unit nearly constant, and the overall system operates with a favorable efficiency. Advantageously, the distribution and collection lines of the heat exchanger unit are located outside the areas where ice can form.

[0036] According to a favorable design of the latent heat storage system, the at least one module with its heat exchanger plates can have a distance from the bottom of the container such that the storage medium within this distance remains ice-free even in the coldest operating condition of the at least one module. If the heat exchanger plates of the module are arranged on a pallet, the distance essentially corresponds to that between the end faces of the heat exchanger plates facing the bottom of the container.

[0037] With a well-designed latent heat storage system, the storage container can be pre-assembled with at least one module. This simplifies transport logistics to the consumer and on-site installation.

[0038] With a favorable design of the latent heat storage system, the storage container can be thermally coupled to its surroundings. In particular, the storage container can be located underground during operation.

[0039] According to a further aspect of the invention, an energy supply system with at least one latent heat storage unit is proposed. The latent heat storage unit for providing heat and cold to a consumer is equipped with a storage container for receiving a storage medium in an interior space and a heat exchanger unit arranged therein, which is in thermal contact with the storage medium and through which a heat transfer fluid flows during operation. The heat exchanger unit has heat exchanger plates, each of which is through which the heat transfer fluid flows. The heat exchanger plates of the heat exchanger unit are designed as at least one module. The heat exchanger plates of the at least one module are arranged transversely to a vertical axis of the storage container at a first predetermined distance from each other. The at least one module is arranged with its heat exchanger plates at a distance from the bottom and the wall of the container.The heat exchanger plates are arranged on a pallet with their end faces facing the bottom of the container as intended.

[0040] At least one module, with its heat exchanger plates along the vertical axis, occupies at most half of the target level of the storage medium in the interior.

[0041] The heat exchanger unit is coupled to a heat pump, which extracts heat from the storage medium at least temporarily via the heat exchanger unit, and to a regeneration system, which supplies heat to the storage medium at least temporarily via the heat exchanger unit, as well as to a control and / or regulation unit, which controls or regulates at least the cooling and heating of the heat exchanger unit.

[0042] The heat exchanger unit can be connected to the heat pump and the regeneration system via a hydraulic module, which includes system hydraulics and a control and / or regulation unit. The regeneration system can advantageously incorporate a roof absorber and / or an energy fence. Optionally, additional heat generators can also be integrated to support the regeneration, i.e., the heating, of the heat exchanger unit. Both sensible and latent energy can be extracted from the heat exchanger unit via the heat pump.

[0043] The heat exchanger unit can optionally also be used for a regeneration system as an absorber, energy fence, etc.

[0044] Renewable energy can be supplied to the latent heat storage system via the regeneration system and / or other heat generators. A consequence of this heat extraction is the formation of ice sheets, up to 30 mm thick, on the surfaces of the heat exchanger plates. To interrupt this icing process, the heat exchanger unit can be switched from extraction to regeneration. This causes the ice sheets to detach from the surfaces of the heat exchanger plates. Due to gravity, the ice pieces float to the surface of the storage medium, especially the water surface, and the heat exchanger plates are once again in contact with the storage medium (usually water). The icing process, and thus the utilization of the heat of crystallization or the building up of further cooling capacity, can then begin anew.

[0045] The thickness of the ice plates can be controlled by adjusting the regeneration time. An emergency switch can be advantageously incorporated to prevent the ice plates from becoming too thick and merging. This ensures that no unwanted pressure forces act within the heat exchanger unit.

[0046] With a favorable design of the energy supply system, a switching device can be arranged between the latent heat storage, heat pump, and regeneration system. This device must include at least one switching valve for influencing the flow direction of the heat transfer fluid, at least one temperature sensor for measuring the temperature of the heat transfer fluid, and at least one volume flow sensor for detecting a heating and / or cooling demand from the heat pump. Advantageously, the heat transfer fluid can be selectively routed between the components as needed.

[0047] With a favorable design of the energy supply system, at least one mixing valve can be arranged in a flow connection between the latent heat storage, heat pump, and regeneration system. This valve mixes the heat transfer fluid from the regeneration system with the heat transfer fluid from the heat exchanger unit. The mixing ratio can be adjusted so that the heat transfer fluid supplied to the primary side of the heat pump is at a temperature favorable for heat pump operation.

[0048] Depending on the operating conditions of the heat exchanger unit and / or heat pump, different heat transfer fluid circuits can be present in the energy supply system, depending on the operating conditions. In a first operating mode, a first heat transfer fluid circuit can be configured between the latent heat storage unit and a primary side of the heat pump. In a second operating mode, a second heat transfer fluid circuit can be configured between the regeneration system and the heat pump. In a third operating mode, a third heat transfer fluid circuit can be configured between the regeneration system and the heat exchanger unit of the latent heat storage unit. In particular, a switching device with at least one switching valve can be provided for switching between the circuits. The different circuits are activated depending on the operating conditions of the heat exchanger unit and / or heat pump.

[0049] When the first circuit is active, the heat exchanger unit extracts heat from the storage medium of the latent heat storage and cools it down accordingly, whereby the appropriately tempered heat transfer fluid is supplied to the heat pump for heating purposes or, if necessary, also for cooling purposes.

[0050] When the second circuit is active, the regeneration system extracts heat from the environment, for example, and the heat transfer fluid at the appropriate temperature is supplied to the heat pump for heating purposes or, if necessary, for cooling purposes.

[0051] When the third circuit is active, the heat exchanger unit is heated by the warmer heat transfer fluid of the regeneration system, thus warming the entire storage medium. Any ice present on the heat exchanger plates may also melt. This latter process can occur intermittently, particularly during a heat extraction period when the latent heat storage system is cooled by heat removal.

[0052] With a suitable design of the energy supply system, depending on the operating conditions of the heat exchanger unit and / or heat pump, a further operating mode allows heat transfer fluid from the heat exchanger unit and from the regeneration system to be mixed and supplied to the primary side of the heat pump. By mixing the heat transfer fluid from the regeneration system and the heat transfer fluid from the heat exchanger unit, the heat transfer fluid at a temperature optimal for heat pump operation can be supplied to the primary side of the heat pump. The mixing ratio can be adjusted as required.

[0053] With a favorable design of the energy supply system, latent heat storage, a heat pump, and a regeneration system can be connected to a hydraulic module, which includes the switching device with at least one switching valve, at least one temperature sensor, and at least one flow sensor. Advantageously, the hydraulic module can also include a means of conveying the heat transfer fluid. Separately, the heat pump can have its own primary-side pump.The hydraulic module is advantageously designed as a self-contained device with its own control and / or regulation unit, which, based on the signals from the at least one volume flow sensor and the temperature signals of the heat transfer fluid in the hydraulic module, autonomously operates the switching device and, if necessary, the mixing valve in order to meet the heating and, if necessary, cooling requirements of the heat pump or the thermal regeneration of the heat exchanger unit in the latent heat storage or also a thermal regeneration of the regeneration system.

[0054] Advantageously, the latent heat storage system, heat pump, and regeneration system only need to be fluidically connected to the hydraulic module. The usual control unit of the heat pump does not need to be adapted to the hydraulic module and its control system.

[0055] According to a further aspect of the invention, a method for operating an energy supply system with at least one latent heat storage unit is proposed, wherein the latent heat storage unit provides heat and cold to a consumer via a heat exchanger unit that is in thermal contact with the storage medium and through which a heat transfer fluid flows during operation. The heat exchanger unit is coupled to a heat pump, which at least intermittently extracts heat from the storage medium via the heat exchanger unit, and to a regeneration system, which at least intermittently supplies heat to the storage medium via the heat exchanger unit, as well as to a control and / or regulation unit, which controls or regulates at least the cooling and heating of the heat exchanger unit.When heat is extracted from the storage medium, ice formation on the heat exchanger plates of the heat exchanger unit is temporarily interrupted, and the ice is removed from the heat exchanger plates. Defrosting of the heat exchanger plates occurs depending on the outlet temperature of the heat transfer fluid at or after exiting the heat exchanger unit, as soon as the outlet temperature reaches or falls below a preset temperature threshold.

[0056] The latent heat storage system, in particular ice energy storage, is equipped with one or more interconnected modules of the heat exchanger unit, each consisting of several heat exchanger plates, which enable the extraction of heat from the storage medium and the regeneration of the latent heat storage system or the storage medium of the latent heat storage system, i.e. its heating.

[0057] Ideally, a hydraulic module with system hydraulics and a control and / or regulation unit for heat source management is present.

[0058] The system hydraulics include all lines for the heat transfer fluid as well as pumps, sensors, and actuators for operating the hydraulic module. The control unit can determine, depending on the situation, which energy source should be used or when the latent heat storage should be regenerated by balancing the temperatures in the heat transfer fluid circuits. When energy is used below the freezing point of the storage medium, crystallization energy is utilized, and ice sheets several centimeters thick form on the surfaces of the heat exchanger plates. If the temperature of the heat transfer fluid flowing through the heat exchanger unit falls below a defined threshold, the heat exchanger plates are flushed with warm heat transfer fluid, particularly brine, from the regeneration system or other existing heating circuits. This causes the ice sheets to detach from the heat exchanger plates and float to the water surface due to gravity.Regeneration can also be achieved using an electric heating element. The energy supplied in this way is fully utilized and retained as sensible heat. Determining the ice thickness is crucial for successful system operation. The ice thickness on the heat exchanger plates is determined by measuring the change in temperature of the heat transfer fluid at its outlet from the heat exchanger unit, a measurement that can be advantageously acquired in the hydraulic module. This eliminates the need for complex sensor wiring in the heat exchanger unit or the latent heat storage system.

[0059] The thermal regeneration of the heat exchanger unit can be achieved via absorbers of the regeneration system, such as roof absorbers, energy fences, and the like, existing heating circuits at the consumer's premises, an electric heating element, particularly in the latent heat storage system, or other sources. Optionally, several such components can also be combined.

[0060] This process is controlled by monitoring the changing temperatures within the heat transfer fluid circuit. The outlet temperature of the heat transfer fluid as it exits the heat exchanger unit is measured in the hydraulic module. Once this temperature reaches or falls below a threshold, for example, between -4°C and -8°C, the regeneration of the heat exchanger unit is activated for a specific period.

[0061] For this purpose, warm heat transfer fluid, particularly from the regeneration system, is supplied to the heat exchanger unit and / or the storage medium is heated, for example, by an electric heating element. The precise end of the regeneration process is also controlled by the outlet temperature of the heat transfer fluid as it exits the heat exchanger unit, as measured by the hydraulic module. As soon as this outlet temperature rises above freezing, the defrosting process can be terminated.

[0062] The set temperature threshold of the heat transfer fluid from the heat exchanger unit defines the thickness of the ice sheets that form on the heat exchanger plates. A corresponding graphic can also be created and stored in the control unit.

[0063] For reasons of system efficiency, the regeneration system and any existing heating circuits are used first when removing ice. If the temperature at the inlet of the heat exchanger unit (inlet temperature) is not at least 4 K above freezing, an electric heating element can be activated. The higher the temperature of the warm heat transfer fluid is above freezing during regeneration, the shorter the melting time. With a temperature threshold between -4°C and -8°C, the melting time can be advantageously only a few minutes, so that the heat exchanger unit is quickly available again to extract heat from the storage medium.

[0064] The melting of the ice itself is energetically efficient, as the energy expended is stored as sensible heat in the latent heat storage system and can be used again later. The heat extraction is therefore only briefly interrupted by the melting of the ice.

[0065] Because the ice detaches from the surface of the heat exchanger plates at slightly below 0°C, the temperature of the ice cannot fall below approximately -2°C due to the lack of further energy input at the water surface. Consequently, the inflow of geothermal heat through the storage tank walls prevents ice from forming at the tank's edge. Therefore, the risk of explosion is avoided.

[0066] In a favorable embodiment of the method, the preset temperature threshold of the heat transfer fluid exiting the heat exchanger unit can be selected such that the ice thickness on the heat exchanger plates of the at least one module is less than half the first target distance between the heat exchanger plates of the at least one module. In particular, the temperature threshold can be selected in the range of -5°C to -9°C, preferably in the range of -4°C to -8°C. The ice thickness on the surface of the heat exchanger plates can be reliably determined from the outlet temperature of the heat transfer fluid exiting the heat exchanger unit, without having to intervene in a module of the heat exchanger unit or the latent heat storage system.

[0067] In a favorable embodiment of the process, heat can be supplied until the outlet temperature reaches or exceeds 0°C. Advantageously, the heat extraction from the latent heat storage is only interrupted briefly.

[0068] In a favorable embodiment of the process, in a first operating mode, heat transfer fluid flows in a first circuit between the latent heat storage and a primary side of the heat pump, and in a second operating mode, heat transfer fluid flows in a second circuit between the regeneration system and the heat pump. Depending on the operating conditions of the heat exchanger unit and / or the heat pump, switching between the first and second circuits is possible. The heat pump receives heat transfer fluid within a favorable temperature range. The heat exchanger unit is automatically defrosted when a temperature threshold for the outlet temperature is reached or fallen below, and is then available again for heat extraction from the storage medium.In a third operating mode, heat transfer fluid can flow in a third circuit between the heat exchanger unit of the latent heat storage system and the regeneration system, allowing the storage medium to be heated and, in particular, enabling the defrosting of ice from the surface of the heat exchanger plates. Switching between the circuits is possible depending on the operating conditions of the heat exchanger unit and / or the heat pump. drawing

[0069] Further advantages will become apparent from the following description of the drawings. The figures illustrate exemplary embodiments of the invention. The figures, the description, and the claims contain numerous features in combination. It will be advantageous for those skilled in the art to also consider the features individually and combine them into meaningful further combinations.

[0070] They show, for example: Fig. 1 schematically represents an energy supply system according to an embodiment of the invention; Fig. 2 a module of a heat exchanger unit with heat exchanger plates; Fig. 3 a front view of a module according to Figure 2 Fig. 4 shows different distances with respect to a module according to an embodiment of the invention; Fig. 5 shows a schematic representation of a latent heat storage unit with a hydraulic module according to an embodiment of the invention; Fig. 6 shows a schematic representation of different circuits of a heat transfer fluid depending on the requirements of a heat exchanger unit and / or heat pump; Fig. 7 shows a flow diagram for the intermittent defrosting of a heat exchanger unit according to an embodiment of the invention; Fig. 8 shows a flow diagram for the intermittent defrosting of a heat exchanger unit according to a further embodiment of the invention. Embodiments of the invention

[0071] In the figures, similar or equivalent components are numbered with the same reference symbols. The figures merely show examples and are not to be understood as limiting.

[0072] Before the invention is described in detail, it should be noted that it is not limited to the respective components of the device or the respective process steps, as these components and processes can vary. The terms used here are intended solely to describe particular embodiments and are not used restrictively. Furthermore, where the singular or indefinite articles are used in the description or in the claims, this also refers to the plural of these elements, unless the overall context clearly indicates otherwise.

[0073] The directional terminology used below, including terms like "left," "right," "above," "below," "in front," "behind," "after," and the like, serves only to improve the understanding of the figures and is in no way intended to limit their generality. The components and elements depicted, their interpretation, and their use may vary according to the considerations of a person skilled in the art and be adapted to the specific applications.

[0074] Figure 1 Illustrates schematically an energy supply system 200 according to an embodiment of the invention, and Figure 2Figure 40 shows a heat exchanger unit that can be advantageously used in the energy supply system 200. Such a heat exchanger unit 40 will advantageously be installed in a latent heat storage unit 100. Alternatively or additionally, such a heat exchanger unit 40 can also be used in a regeneration system of the energy supply system 200.

[0075] The energy supply system 200 includes a latent heat storage unit 100. The latent heat storage unit 100 has a storage tank 10, which is designed to hold a storage medium 12 containing latent heat. The storage medium 12 is, for example, water. The latent heat storage unit serves as the primary energy source.

[0076] In the storage container 10, a heat exchanger unit 40 is arranged in the storage medium 12, which is designed for exchanging heat with the storage medium 12 and includes at least one module 50 ( Figure 2) which, during operation, is traversed by a heat transfer fluid 52. The module 50 is formed by a plurality of heat exchanger plates 60 arranged parallel and spaced apart from each other, which extend parallel to the vertical axis 110 of the storage tank 10.

[0077] Two or more such modules can be used if needed (50 Figure 2 ) are interconnected and form the heat exchanger unit 40.

[0078] The heat transfer fluid 52 is, for example, brine or a glycol-water mixture or the like.

[0079] The energy supply system 200 further comprises a heat pump 210, whose primary side is fluidically connected to the heat exchanger unit 40 of the latent heat storage unit 100, as well as a second energy source in the form of a regeneration system 220, for example in the form of a roof absorber and / or an energy fence. The energy supply system 200 also includes a hydraulic module 1000 with the system hydraulics 300 and an associated control and / or regulation unit 350, which is connected to the system hydraulics 300.

[0080] The system hydraulics 300 fluidically connects the heat exchanger unit 40 of the latent heat storage unit 100, the regeneration system 220, and the heat pump 210. The heat pump 210 is coupled to the hydraulic module 1000 via a fluid interface 212, the heat exchanger unit 40 via a fluid interface 102, and the regeneration system 220 via a fluid interface 222, with the fluid interfaces 102, 212, and 222 each comprising connections for the inlet and outlet of heat transfer fluid 52 into and from the components 100, 210, and 220, respectively.

[0081] The heat pump 210 supplies a consumer 150, for example a single-family house, with heat or, if required, with cooling. For this purpose, a subsidy 214 is provided, for example, which pumps a heat transfer fluid from the secondary side of the heat pump 210 to the consumer 150.

[0082] Figure 2 shows a heat exchanger unit 40, as used in the latent heat storage unit 100 in Figure 1can be used and is in thermal contact with the storage medium 12 in the interior 14 of the storage container 10 and is permeated by a heat transfer fluid 52 in the operating state. Figure 3 shows a top view of module 50 of heat exchanger unit 40. Figure 4 are different distances relating to the heat exchanger unit 40 in the storage tank 10 ( Figure 1 ) indicated.

[0083] The heat exchanger unit 40 comprises at least one module 50 with heat exchanger plates 60, each of which is permeated by the heat transfer fluid 52. The heat exchanger plates 60 of the heat exchanger unit 40 are designed as a compact module 50, which can be connected to further modules 50 in the latent heat storage unit 100 as required. The heat exchanger unit 40 supplies sensible and latent heat from the latent heat storage unit 100 to the primary side of the heat pump 210.

[0084] The heat exchanger plates 60 in the module 50 are arranged transversely to a vertical axis 110 of the storage vessel 10 at a first target distance 62. The module 50, with its heat exchanger plates 60, is spaced apart from the vessel bottom 16 and the vessel wall 18. The module 50, with its heat exchanger plates 60 along the vertical axis 110, occupies at most half of a target level 20 of the storage medium 12 in the interior 14.

[0085] Module 50 has a distribution line 80 and a collection line 90, with fluid inlets 64 of the heat exchanger plates 60 opening into the distribution line 80 and fluid outlets 68 of the heat exchanger plates 60 opening into the collection line 90 for the heat transfer fluid 52. The heat exchanger plates 60 are connected in parallel for flow purposes. If two or more modules 50 are arranged in the latent heat storage unit 100, a common distribution line 80 and a common collection line 90 can be provided for all of them. Optionally, each module 50 can have its own distribution line 80 and its own collection line 90. The lines are advantageously arranged in the ice-free area.

[0086] Module 50, with its heat exchanger plates 60 along the vertical axis 110, occupies at most one-third of the target level 20 of the storage medium 12. As intended, ice forms on the surface of the heat exchanger plates 60 when heat is extracted from the latent heat storage medium 100. This ice melts, essentially in pulses, when a predetermined ice thickness is reached. Minor fluctuations in the level 20 during ice formation on the heat exchanger plates 60 of the heat exchanger unit 40, or during the melting of the ice, can be disregarded compared to the distances involved.

[0087] The ice detached from the heat exchanger unit 40 can be collected in the free space 24 above the heat exchanger unit 40, which is located close to the bottom of the storage tank 10, without exerting any undesirable forces on the heat exchanger unit 40 or the storage wall 18 or the storage bottom 16 of the storage tank 10.

[0088] Module 50, with its heat exchanger plates 60, has a heat extraction area of ​​at least approximately 2 to 2.5 m², with a suitable width of the heat exchanger plates 60 of, for example, approximately 800 mm to 1200 mm and a height of up to 1200 mm. A module 50 of a heat exchanger unit 40 can advantageously consist of 8 to 12 heat exchanger plates 60 and is sufficient to supply a single-family home with approximately 150 m² of heated floor space, for example, in Central Europe, providing it with heat and, if necessary, cooling throughout the year. Should more capacity be required, additional modules 50 can be installed and connected together.

[0089] The module 50, with its heat exchanger plates 60, has a volume of at most 20%, preferably 15%, and particularly preferably at most 10% of the volume of the storage medium 12. The volume refers to the outer dimensions of an envelope of the heat exchanger plates 60 in the module 50, which are arranged, for example, in a cuboid as an envelope.

[0090] Module 50, with its heat exchanger plates 60, has a distance 54 from the bottom of the container 16, which is dimensioned such that the storage medium 12 within the distance 54 remains ice-free even in the coldest operating condition of module 50 as intended. According to the invention, the heat exchanger plates 60 are arranged with their end faces facing the bottom of the container 16 on a pallet 65, which has corresponding spacers 66 to the bottom of the container 16.

[0091] The storage tank 10 is thermally coupled to its surroundings and is located underground during operation. This allows it to absorb ambient heat, as the soil surrounding the storage tank 10 typically maintains a temperature above freezing year-round.

[0092] The modular design of the heat exchanger unit 40 allows the storage tank 10 to be pre-assembled with at least one module 50. The latent heat storage unit 100 can be easily transported to the installation site by road and simply needs to be placed in a prepared pit and, if necessary, filled with storage medium 12 and / or heat transfer fluid 52.

[0093] Depending on the operating conditions of heat exchanger unit 40 and / or heat pump 210 in a first operating mode, a first circuit 202 of the heat transfer fluid 52 is formed between latent heat storage unit 100 and a primary side of the heat pump 210. In a second operating mode, a second circuit 204 of the heat transfer fluid 52 is formed between regeneration system 220 and heat pump 210.

[0094] A switching device (not shown) allows switching between the two circuits 202 and 204, so that when heat is drawn by the heat pump 210, the more efficient energy source for the heat pump 210, namely latent heat storage 100 or regeneration system 220, always supplies heat to the heat pump 210. Optionally, the heat transfer fluid 52 can be mixed, so that the heat pump 210 receives heat transfer fluid 52 at a mixture temperature from the first and second circuits 202 and 204.

[0095] In another operating mode, a third circuit 206 is formed between the latent heat storage unit 100 and the regeneration system 220. This allows for the regeneration of the latent heat storage unit 100 after the extraction period, during which its storage medium 12 is heated. Furthermore, this allows for the short-term regeneration of the heat exchanger unit 40 during the extraction period, when ice that forms on the surface of the heat exchanger plates 60 is briefly removed to improve thermal contact with the storage medium 12.

[0096] Switching is conveniently carried out by the control and / or regulation unit 350 of the hydraulic module 1000, which, on the one hand, detects a demand from the heat pump 210 via volume flow measurement and temperature measurement and switches the circuits 202, 204 accordingly, and, on the other hand, detects via the measurement of the outlet temperature of the heat transfer fluid 52 from the heat exchanger unit 40 whether there is ice on the surface of the heat exchanger plates 60 and whether this should be removed.

[0097] The hydraulic module 1000 contains all components, i.e. valves, temperature sensors, conveying elements, flow sensors and the like, necessary for autonomous operation, so that intervention in a control system of the heat pump 210 is not necessary.

[0098] The Figure 7 and 8Figure 1 schematically illustrates embodiments of a method for operating an energy supply system 200 with at least one latent heat storage unit 100, which provides heat and cold to a consumer 150 via a heat exchanger unit 40. The heat exchanger unit 40 is to be defrosted during the extraction period in order to be ready for heat extraction again afterwards.

[0099] In step S100, the hydraulic module 1000 ( Figure 1 , 5 The outlet temperature T_40 of the heat transfer fluid 52 from the heat exchanger unit 40 is recorded. This can be done continuously or periodically. For this purpose, temperature sensors are arranged in the system hydraulics 300.

[0100] In step S102, the control unit 350 of the hydraulic module 1000 checks whether the outlet temperature T_40 is equal to or below a temperature threshold T_REG at which the regeneration of the heat exchanger unit 40 is to take place. The temperature threshold T_REG corresponds to a defined thickness of ice on the surface of the heat exchanger plates 60 and is preferably in the range of -4°C to -8°C.

[0101] If T_40≤T_REG ("j" in the flowchart), the heat exchanger unit 40 is regenerated in step S104. If T_40 is above the temperature threshold T_REG ("n" in the flowchart), further heat is extracted from the latent heat storage unit 100.

[0102] In step S106, the control unit 350 of the hydraulic module 1000 checks whether the outlet temperature T_40 exceeds a certain temperature value, for example, 0°C. If this is the case ("j" in the flowchart), the control unit 350 of the hydraulic module 1000 switches back to the extraction mode in step S120. If this is not the case ("n" in the flowchart), the regeneration process continues in step S104.

[0103] Figure 8 shows one variant of the procedure. Steps S100-S106 proceed as in Figure 7 ab, to which reference will be made to avoid unnecessary repetition.

[0104] If the outlet temperature T_40 in step S106 exceeds a temperature value, for example 0°C ("j" in the flowchart), step S110 checks whether the inlet temperature T_1 of the heat transfer fluid 52 entering the heat exchanger unit 40 is higher than the outlet temperature T_40 by a defined value, for example 4 K. If this is the case ("j" in the flowchart), the system switches to extraction mode in step S120. If the temperature difference is smaller ("n" in the flowchart), a heat source, for example an electric heating element in the storage medium 12, is activated in step S112 to heat the storage medium 12. In step S114, it is again checked whether the inlet temperature T_1 of the heat transfer fluid 52 entering the heat exchanger unit 40 is higher than the outlet temperature T_40 by a defined value, for example 4 K. If this is the case ("j" in the flowchart), the system switches to withdrawal mode in step S120.If the temperature difference is smaller ("n" m flow diagram), the storage medium 12 continues to be heated by means of the additional heating source. Reference sign

[0105] 10 Storage tank 12 Storage medium 14 Interior 16 Tank bottom 18 Tank wall 20 Target level 22 Distance 24 Free space 40 Heat exchanger unit 50 Module 52 Heat transfer fluid 54 Target distance 60 Heat exchanger plate 62 Target distance 64 Fluid inlet 65 Pallet 66 Spacer 68 Fluid outlet 80 Distribution line 82 Line 90 Manifold 92 Line 100 Latent heat storage 102 Interface 110 Vertical axis 150 Consumer 200 Energy supply system 202 Circuit 204 Circuit 210 Heat pump 212 Interface 214 Conveyor 220 Regeneration system 222 Interface 300 System hydraulics 350 Control and / or regulation unit 1000 Hydraulic module S100 Process step S102 Process step S104 Process step S106 Process step S110 Process step S112 Process step S114 Process step S120 Process step T_40 Outlet temperature T_REG Temperature threshold T_1 Inlet temperature

Claims

1. Latent-heat store (100) for providing heat and cold for a consumer (150), having a storage vessel (10) for receiving a storage medium (12) in an interior space (14), and having a heat-exchanger unit (40) arranged therein which is in thermal contact with the storage medium (12) and which, in the operating state, is flowed through by a heat-carrier fluid (52), wherein the heat-exchanger unit (40) has heat-exchanger plates (60), each of which is flowed through by the heat-carrier fluid (52), wherein the heat-exchanger plates (60) of the heat-exchanger unit (40) are in the form of at least one compact module (50), wherein the heat-exchanger plates (60) of the at least one module (50) are arranged spaced apart from one another by a first desired spacing (62) transversely to a vertical axis (110) of the storage vessel (10), wherein the at least one module (50) is arranged with its heat-exchanger plates (60) spaced apart from the vessel base (16) and from the vessel wall (18), wherein the at least one module (50) occupies at most half of a desired level (20) of the storage medium (12) in the interior space (14) with its heat-exchanger plates (60) along the vertical axis (110), characterized in that the heat-exchanger plates (60) are arranged with their end faces facing the vessel base (16) as intended on a pallet.

2. Latent-heat store according to Claim 1, characterized in that the at least one module (50) has a distributor line (80) and a collecting line (90), in particular in that fluid inlets (64) of the heat-exchanger plates (60) open out into the distributor line (80) and fluid outlets (68) of the heat-exchanger plates (60) open out into the collecting line (90) for the heat-carrier fluid (52), in particular wherein the heat-exchanger plates (60) are connected in parallel in terms of flow.

3. Latent-heat store according to Claim 1 or 2, characterized in that, in the storage vessel (10), distributor lines (80) and collecting lines (90) of multiple, in particular similar, modules (50) are connected together in terms of flow, in particular are connected in parallel in terms of flow.

4. Latent-heat store according to one of the preceding claims, characterized in that the at least one module (50) occupies at most one third of the desired level (20) with its heat-exchanger plates (60) along the vertical axis (110).

5. Latent-heat store according to one of the preceding claims, characterized in that the module (50) has with its heat-exchanger plates (60) a volume of at most 20%, preferably 15%, particularly preferably at most 10%, of the volume of the storage medium (12).

6. Latent-heat store according to one of the preceding claims, characterized in that the at least one module (50) has with its heat exchanger plates (60) a spacing (54) to the vessel base (16) that is of such a magnitude that the storage medium (12) within the spacing (54) is free of ice even in that operating state of the at least one module (50) which is intended to be the coldest.

7. Latent-heat store according to one of the preceding claims, characterized in that the storage vessel (10) is produced prefabricated with the at least one module (50).

8. Use of a latent-heat store according to one of the preceding claims, characterized in that the storage vessel (10) is thermally coupled to its surroundings.

9. Energy-supply system (200) having at least one latent-heat store (100) according to one of Claims 1 to 7, wherein the latent-heat store (100), for providing heat and cold for a consumer (150), is provided with a storage vessel (10) for receiving a storage medium (12) in an interior space (14), and with a heat-exchanger unit (40) arranged therein which is in thermal contact with the storage medium (12) and which, in the operating state, is flowed through by a heat-carrier fluid (52), wherein the heat-exchanger unit (40) has heat-exchanger plates (60), each of which is flowed through by the heat-carrier fluid (52), characterized in that the heat-exchanger plates (60) of the heat-exchanger unit (40) are in the form of at least one module (50), wherein the heat-exchanger plates (60) of the at least one module (50) are arranged spaced apart from one another by a first desired spacing (62) transversely to a vertical axis (110) of the storage vessel (10), wherein the at least one module (50) is arranged with its heat-exchanger plates (60) spaced apart from the vessel base (16) and from the vessel wall (18) and the heat-exchanger plates (60) are arranged with their end faces facing the vessel base (16) as intended on a pallet, wherein the at least one module (50) occupies at most half of a desired level (20) of the storage medium (12) in the interior space (14) with its heat-exchanger plates (60) along the vertical axis (110), wherein the heat-exchanger unit (40) is coupled to a heat pump (210), which at least temporarily extracts heat from the storage medium (12) via the heat-exchanger unit (40), and to a regeneration system (220), which at least temporarily provides the storage medium (12) with heat via the heat-exchanger unit (40), and to a control and / or regulating unit (350), which controls or regulates at least a cooling and heating of the heat-exchanger unit (40).

10. Energy-supply system according to Claim 9, characterized in that, between the latent-heat store (100), the heat pump (210) and the regeneration system (220), there are arranged a switching device with at least one switching valve for influencing a flow direction of the heat-carrier fluid (52), at least one temperature sensor for detecting the temperature of the heat-carrier fluid (52), and at least one volume-flow sensor (330) for detecting a heating requirement and / or a refrigerating requirement of the heat pump (210).

11. Energy-supply system according to Claim 9 or 10, characterized in that at least one mixing valve, by way of which heat-carrier fluid (52) from the regeneration system (220) and heat-carrier fluid (52) from the heat-exchanger unit (40) are mixed, is arranged in a flow connection between the latent-heat store (100), the heat pump (210) and the regeneration system (220).

12. Energy-supply system according to one of Claims 9 to 11, characterized in that there are different circuits (202, 204, 206) of the heat-carrier fluid (52) according to operating conditions of the heat exchanger unit (40) and / or the heat pump (210), wherein, in a first operating mode, a first circuit (202) of the heat-carrier fluid (52) is formed between the latent-heat store (100) and a primary side of the heat pump (210), wherein, in a second operating mode, a second circuit (204) of the heat-carrier fluid (52) is formed between the regeneration system (220) and the heat pump (210), wherein, in a third operating mode, a third circuit (206) of the heat-carrier fluid (52) is formed between the regeneration system (220) and the heat-exchanger unit (40) of the latent-heat store (210).

13. Energy-supply system according to one of Claims 9 to 12, characterized in that the latent-heat store (100), the heat pump (210) and the regeneration system (220) are connected to a hydraulic module (1000) which has the switching device, has the at least one temperature sensor and has the at least one volume-flow sensor.

14. Method for operating an energy-supply system (200) according to one of Claims 9 to 13, having at least one latent-heat store (100) according to one of Claims 1 to 8, wherein the latent-heat store (100) provides heat and cold for a consumer (150) via a heat-exchanger unit (40) which is in thermal contact with storage medium (12) and which, in the operating state, is flowed through by a heat-carrier fluid (52), wherein the heat-exchanger unit (40) is coupled to a heat pump (210), which at least temporarily extracts heat from the storage medium (12) via the heat-exchanger unit (40), and to a regeneration system (220), which at least temporarily provides the storage medium (12) with heat via the heat-exchanger unit (40), and to a control and / or regulating unit (350), which controls or regulates at least a cooling and heating of the heat-exchanger unit (40), wherein, during extraction of heat from the storage medium (12), ice formation on heat-exchanger plates (60) of the heat-exchanger unit (40) is temporarily interrupted and the ice is removed from the heat exchanger plates (60), wherein the heat-exchanger plates (60) of the heat-exchanger unit (40) are defrosted according to an exit temperature (T_40) of the heat-carrier fluid (52) while or after exiting the heat-exchanger unit (40), as soon as the exit temperature (T_40) reaches or falls below a preset temperature threshold (T_reg).

15. Method according to Claim 14, wherein the preset temperature threshold (T_reg) is selected in such a way that a thickness (D_50) of ice on the heat-exchanger plates (60) of the at least one module (50) is smaller than half the first desired spacing (62) between the heat-exchanger plates (60) of the at least one module (50), in particular wherein the preset temperature threshold (T_reg) is selected in the range between -5°C and -9°C, preferably in the range between -4°C and -8°C.

16. Method according to Claim 14 or 15, wherein heat is supplied until the exit temperature (T_40) reaches or exceeds at least 0°C.

17. Method according to one of Claims 14 to 16, wherein, in a first operating mode, heat-carrier fluid (52) flows in a first circuit (202) between the latent-heat store (100) and a primary side of the heat pump (210) and, in a second operating mode, heat-carrier fluid (52) flows in a second circuit (204) between the regeneration system (220) and the heat pump (210) and, in a third operating mode, heat-carrier fluid (52) flows in a third circuit (206) between the regeneration system (220) and the latent-heat store (100), wherein switching between the circuits (202, 204, 206) is realized according to operating conditions of the heat-exchanger unit (40) and / or the heat pump (210).

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