Device for heating hot water for domestic use

Abstract

Device (1) for heating domestic water by thermal contact with a heating fluid, the device comprising a first chamber (10) and a second chamber (20) fluid-dynamically connected to the first chamber via a connecting opening (13), both the first chamber and the second chamber each having a supply opening (11, 21) and a removal opening (12, 22) for heating fluid, the first chamber being designed to store heating fluid in its interior in layers (14, 15, 16) lying one above the other in a stratification direction (19) according to the temperature of the heating fluid. Specific guidance of the flow of the heating fluid, on the one hand during layering into the first chamber and, on the other hand, during flowing into the second chamber, leads to high efficiency of heat transfer to the domestic water.Furthermore, the invention is directed to a heating system comprising the device, an operating method for the heating system, a single-layer device, and a heat exchanger device. The invention enables, for example, the implementation of various embodiments of the heating system and their operating methods using only a single pump.

Description

[0001] The present invention relates to the technical field of heating and sanitary engineering. In particular, it concerns a device for heating domestic hot water, a heating system comprising such a device, elements of such a device, and an operating method for the heating system.

[0002] Promoted by environmental and energy policy, air-source heat pumps are currently in high demand for heating buildings. Such air-source heat pumps use outside air as a heat source. Thermal energy is extracted from the outside air at the heat pump's evaporator by converting a refrigerant from a liquid to a gaseous state. The refrigerant is compressed by an electrically driven compressor in a high-pressure zone of the heat pump. The refrigerant condenses in a condenser of the heat pump and can thus release thermal energy to the heating water in this heat exchanger. The refrigerant circuit runs through an expansion valve back to the low-pressure side in the heat pump's evaporator. Of interest in this context is the achievement of high efficiency, i.e. a given thermal output, with the lowest possible electrical power consumption of the compressor.

[0003] A favorable situation for achieving high efficiency arises when heating heating water for underfloor heating, for example. In this case, a flow temperature in the range of 30°C to 35°C is sufficient. Efficiency suffers when radiator heating is used, which requires a flow temperature of 50°C, for example. Even in buildings with underfloor heating, heating domestic hot water, for example for showering, using the same heat pump is desirable. For example, this can be achieved by producing heating water at an elevated temperature, temporarily storing it in a buffer tank, and using two different methods to heat domestic water. 1.: Since the beginning of modern domestic technology 130 years ago, enameled drinking water storage tanks with any capacity have been established, in which the stagnant water is heated using various methods. Initially, the boilers were heated with coal or wood, later with gas, oil, and electricity, as well as heat pumps. A common feature of all previous boiler generations is the high temperature at which the finished domestic hot water was and is temporarily stored. In view of the replacement of fossil fuels, this method is no longer up to date. However, a heat pump can only operate economically if the flow temperatures are as low as possible. 2.: The fresh water instantaneous water heater process, developed 125 years ago, has a much better future.

[0004] Initially powered by gas, electric instantaneous water heaters were later introduced, converting electricity directly into heat. With the advent of heat pumps for space heating, a domestic hot water heating process based on fresh water instantaneous heating became popular. A tank of heated heating water serves as an energy reserve. When needed, the warm heating water is brought into thermal contact with the cold fresh water in a heat exchanger. The stainless steel plate heat exchangers used exclusively as heat exchangers for this application have several disadvantages. Due to their internal design, sufficiently smooth surfaces are present, which promote the tendency of flowing fluids to flow in a laminar manner. The resulting thermal boundary layers lead to large temperature differences during heat exchange.This, in turn, is detrimental to energy efficiency and leads to calcification of the internal heat exchanger surfaces.

[0005] Heating the heating water to the temperature of 45 to 55°C required for domestic hot water production results in the heat pump operating, at least temporarily, in a mode that generates a higher flow temperature. This reduces the overall efficiency of the heating system, since only a heating water temperature of 30 to 35°C is required for the underfloor heating system to operate.

[0006] The object of the present invention was to provide a device or method that improves the efficiency of domestic hot water production. In particular, one object was to create a device or method that enables switching between space heating and domestic hot water heating without having an excessively negative impact on the overall efficiency of the heating system.

[0007] This object is achieved according to the invention by a device according to claim 1. Embodiments of the device result from the features of claims 2 to 8.

[0008] The device according to the invention is a device for heating domestic water through thermal contact with a heating fluid. The device has a first chamber and a second chamber fluid-dynamically connected to the first chamber via a connecting opening. The first and second chambers serve to hold heating fluid. Both the first chamber and the second chamber each have a supply opening and a removal opening for heating fluid. The first chamber is designed to store heating fluid in its interior in layers one above the other, corresponding to the temperature of the heating fluid. During operation, the layers lie on top of one another in a stratification direction that corresponds to the direction of gravity, with the cold layers at the bottom and the warm layers at the top.

[0009] A pipe arrangement for the passage of domestic water leads from an inlet opening for cold domestic water into the second chamber, through the second chamber, through the first chamber and to an outlet opening for heated domestic water.

[0010] A wall arrangement within the first chamber is designed such that heating fluid can be passed from a high-temperature layer between the walls of the wall arrangement and through the connecting opening into the second chamber. When heating fluid is passed from the first chamber into the second chamber in this way, the heating fluid flows around a section of the line arrangement.

[0011] The heating fluid can, in particular, be water. Due to water's relatively high heat capacity, it also allows the storage of heat energy in a relatively small volume.

[0012] The piping system for conveying domestic water separates the clean, fresh domestic water from the heating fluid, while allowing the transfer of thermal energy from the heating fluid to the domestic water. The elements of the piping system are preferably good thermal conductors. In particular, they can be made of a metal, e.g., copper or stainless steel. Furthermore, the elements of the piping system have the smallest possible wall thickness, which is sufficient to meet the mechanical stability requirements.

[0013] The pipe arrangement for conveying domestic water can be designed, in sections or completely, as a corrugated pipe, particularly as a corrugated pipe made of stainless steel. Compared to a smooth-walled pipe, a corrugated pipe has the effect that the flow repeatedly detaches from the pipe wall in a turbulent manner. In this way, domestic water flowing in the pipe arrangement, which has been heated upon contact with the pipe wall, is quickly mixed again with domestic water in the center of the pipe. The transfer of heat energy to the domestic water is thus highly efficient and requires a smaller temperature difference than with a smooth pipe. The pipe arrangement in the form of a corrugated pipe has the surprising advantage that micro-vibrations in the corrugated pipe cause developing layers of limescale to flake off, thus counteracting calcification. A consistently low water temperature inside the pipe also counteracts calcification.Even at a heating water temperature of, for example, 60°C and higher, thermal boundary layers cannot form on the inner pipe wall due to the high turbulence, which in this case could have a temperature of close to 60°C. From 57°C, water-insoluble limescale is increasingly formed, which adheres to the inner pipe wall. This property is advantageous for the preparation of domestic hot water. The heat transfer from the heating water to the outer pipe surface occurs in a highly turbulent manner in this design. Driven by the circulation pump, the heating water can only flow through the corrugated pipe troughs in the space between the inner and outer pipes. This means that no laminar flow is possible, since a permanent conversion of dynamic pressure into static pressure occurs.According to Bernoulli's law, fluid pressure is converted into velocity in the trough of the wave, and after the trough, the increased flow velocity is converted back into pressure energy. The result is a pulsating, high-frequency pumping of the heating water in the annular gap of the heat exchanger. No laminar flow can develop. A higher heat transfer coefficient alpha cannot be achieved in any comparable process.

[0014] The pipe arrangement for conveying domestic water can, for example, be spiral-shaped. The wall arrangement can be shaped so that the heating fluid flows around the pipe arrangement in close contact, creating a turbulent flow.

[0015] Embodiments of the device result from the features of claims 2 to 8.

[0016] In one embodiment of the device, the supply opening of the first chamber is fluid-dynamically connected to the interior of the first chamber through a single-layer device. The single-layer device has openings to the interior of the first chamber. These openings are spaced apart from one another in the layering direction. This means that during operation of the device, when layers of heating fluid with different temperatures are present, different layers are accessible via different openings of the single-layer device.

[0017] In one embodiment of the device, the supply opening of the first chamber is fluid-dynamically connected to the interior of the first chamber through a single-layer device. The single-layer device has openings to the interior of the first chamber that are spaced apart from one another in the layering direction.

[0018] In one embodiment of the device, the wall arrangement comprises an inner and an outer cylindrical wall. The two walls are arranged coaxially with each other. The conduit arrangement, for example, runs helically in one section between the inner and outer cylindrical walls.

[0019] In one embodiment of the device, the line arrangement is at least partially designed as a corrugated pipe. This results in turbulent flow. Furthermore, a corrugated pipe can be easily installed in various geometries.

[0020] In one embodiment of the device, an obstruction element within the single-layer device blocks a direct path from the supply opening for heating fluid to the openings.

[0021] In one embodiment of the device, the single-layer device comprises an outer tube and an inner tube arranged coaxially therein as a barrier element. The plurality of openings to the interior of the first chamber are arranged in the outer tube on a first side, and the bores in the inner tube lead from an inner side of the inner tube into a space between the inner tube and the outer tube. The bores are opposite the first side with respect to a common axis of the two tubes.

[0022] In one embodiment of the device, the single-layer device comprises a flow damping element. The flow damping element can, in particular, be designed as a pipe section filled with steel wool.

[0023] An embodiment of the device additionally comprises a heat exchanger in the first chamber with connections leading out of the first chamber for connection to a thermosolar heat source.

[0024] The invention is also directed to a heating system according to claim 9.

[0025] The heating system according to the invention comprises a heat pump with a heat exchanger, a pump - in particular a single pump - connected in series with the heat exchanger for pumping the heating fluid, a heating circuit for heating a building and a device according to the invention.

[0026] An outlet of the heat exchanger can be fluid-dynamically connected via a first switching valve to the heating circuit (103) or to the supply opening of the first chamber. A suction side of the pump can be fluid-dynamically connected via a second switching valve to the extraction opening of the first chamber or to the extraction opening of the second chamber. Furthermore, a return connection fluid-dynamically connects the heating circuit to the supply opening of the second chamber.

[0027] Furthermore, the invention is directed to an operating method according to claim 10.

[0028] The operating method is used to operate a heating system according to the invention. The following operating states are set alternately: a) Heating operating mode, wherein the first switching valve is set such that the outlet of the heat exchanger is fluid-dynamically connected to the heating circuit and wherein the second switching valve is set such that the suction side of the pump is fluid-dynamically connected to the discharge opening of the second chamber; b) Charging operating mode of the first chamber with warm water, wherein the first switching valve is set such that the outlet of the heat exchanger is fluid-dynamically connected to the supply opening of the first chamber and wherein the second switching valve is set such that the suction side of the pump is fluid-dynamically connected to the discharge opening of the first chamber;c) Operating state of withdrawal of heated domestic water, wherein the first switching valve is set so that the outlet of the heat exchanger is fluid-dynamically connected to the supply opening of the first chamber, wherein the second switching valve is set so that the suction side of the pump is fluid-dynamically connected to the withdrawal opening of the second chamber and wherein cold domestic water flows in through the inlet opening and heated domestic water is withdrawn from the outlet opening. ;

[0029] In a variant of the operating method, the device is a device according to claim 7. A thermosolar heat source is connected to the heat exchanger in the first chamber and, in addition, a further operating state can be set: d) Operating state heating with solar, wherein the heat pump is not in operation, wherein the first switching valve is set such that the outlet of the heat exchanger is fluid-dynamically connected to the heating circuit and wherein the second switching valve takes on a mixer function so that the suction side of the pump is fluid-dynamically connected to the extraction opening of the first chamber and at the same time to the extraction opening of the second chamber.

[0030] Furthermore, the invention is directed to a single-layer device according to claim 12. This is a single-layer device for the device according to the invention. Such a single-layer device can also be used in other stratified storage systems that do not include all the features of the device according to the invention.

[0031] The invention further relates to a heat exchanger arrangement according to claim 13. This is a heat exchanger arrangement for the device according to the invention. The heat exchanger arrangement comprises walls and at least one section of the conduit arrangement located between the wall elements.

[0032] Embodiments of the present invention are explained in more detail below with reference to figures. Fig. 1 a schematic sectional view of an embodiment of the device; Fig. 2a schematic sectional view of an embodiment of the device, which additionally comprises a single-layer device; Fig. 3 a schematic representation of an embodiment of the heating system in the "heating" operating mode (without solar energy); Fig. 4 a schematic representation of an embodiment of the heating system in the operating mode "charging storage tank for domestic hot water" (without solar energy); Fig. 5 a schematic representation of an embodiment of the heating system in the operating mode "withdrawal of domestic hot water"; Fig. 6 a schematic representation of an embodiment of the heating system in the operating mode "heating with solar energy"; Fig. 7 in sub-figures 7.a) to 7.d) various views of an embodiment of the single-layer device; Fig. 8 in sub-figures 8.a) to 8.c) various views of an embodiment of a heat exchanger arrangement for the device; Fig. 9in sub-figures 9.a) to 9.d) various views of an illustrative model of an embodiment of a heat exchanger with walls and piping arrangement; Fig. 10 in sub-figures 10.a) and 10.b) an embodiment of the device with a specific shape of the first heat exchanger stage for domestic hot water Fig. 11 in sub-figures 11.a) to 11.d) various views of individual elements of an embodiment of the heat exchanger matching the embodiment of the device from Figure 10 ; Fig. 12 in sub-figures 12.a) to 12.e) various views of an embodiment of the single-layer device; Fig. 13 a schematic representation of an embodiment of the heating system in the operating state "defrosting the heat pump"; Fig. 14 a schematic representation of an embodiment of the heating system in the "anti-stagnation mode" operating mode; Fig. 15a schematic representation of an embodiment of the heating system in a first variant of the "cold air conditioning" operating state; Fig. 16 a schematic representation of an embodiment of the heating system in a second variant of the "cold air conditioning" operating mode.

[0033] In Figure 1The fluid dynamic relationships are illustrated schematically in a two-dimensional representation. The device 1 comprises a first chamber 10 with a supply opening 11 and a discharge opening 12 for heating fluid. In the interior 18 of the first chamber, layers of heating fluid can form one above the other depending on the temperature. The chamber is drawn here and in the following figures in the orientation used in operation, namely so that gravity acts from top to bottom. This places a high-temperature layer 14 at the upper end of the first chamber, a medium-temperature zone 15 - or transition zone, in which various medium-temperature layers, or a temperature gradient, build up - in the middle, and a low-temperature layer 16 at the lower end of the first chamber.The layers are therefore arranged in a stratification direction 19 corresponding to the direction of the arrow filled with dots, from warm to cold. The device comprises a second chamber 20. The second chamber is connected to the first chamber via the connecting opening 13. The second chamber has its own supply opening 21 and its own removal opening 22 for heating fluid. As shown below in the context of a complete heating system, heating fluid flowing back from the heating circuit can be redirected through the second chamber. The resulting flow does not disrupt the stratification in the first chamber. The residual heat of the heating fluid flowing back from the heating circuit can be used to preheat the cold domestic water in the second chamber. The pipe arrangement 30 and the second chamber 20 thus form a first stage of a two-stage heat exchanger for heating the domestic hot water.

[0034] The pipe arrangement 30 for domestic water continues into the first chamber. In a section 33, it runs between walls 40', 40'' of a wall arrangement designed such that, when a pressure difference exists between the first and second chambers, heating fluid can be passed from the high-temperature layer between the walls and through the connecting opening 13 into the second chamber. Heating fluid flows around section 33 of the pipe arrangement. This section forms a second stage of the two-stage heat exchanger for domestic water.

[0035] Possible flow directions 17 for the heating fluid are indicated by black arrows at various points in the figure. White arrows indicate the flow direction 34 of the domestic water.

[0036] As an example, the possible locations of a high-temperature layer 14, a medium-temperature zone 15, and a low-temperature layer 16 are shown with dashed lines. Due to the temperature-dependent density, the high-temperature layer is located at the upper end.

[0037] Indicated by dashed lines is a baffle plate 25, optionally arranged in the area of ​​the heating fluid supply opening in the first chamber. Such a baffle plate has the effect that incoming heating fluid leads to less turbulence in the temperature layers than if heating fluid were to flow unhindered into the first chamber. This effect can be further enhanced by using a single-layer device, as discussed in the context of one embodiment. Designs other than the single-layer device schematically indicated here are also possible.

[0038] Figure 2shows an embodiment which is largely identical to the embodiment according to Figure 1corresponds, but additionally comprises a single-layer device 50. The single-layer device 50 is arranged downstream of the supply opening 11. In the embodiment shown, a barrier element 52 blocks the direct path to the openings 51 in the interior 18 of the first chamber. As discussed later, a sequence of several barrier elements is also possible. The barrier element(s) have the effect of largely to maximally calming the flow. Openings 51 are spaced apart from one another in the direction of the layering. In the situation shown, openings lead into the high-temperature layer 14, the medium-temperature zone 15, and the low-temperature layer 16. Strictly speaking, the layers merge seamlessly into one another, and a temperature gradient forms.Depending on the history of heating water loading into the buffer tank and the withdrawal of domestic hot water, the position and extent of cold and warm layers, as well as the steepness of the temperature gradients, shift. Due to the lower density of warm water, the warmest layer is always located at the upper end of the first chamber. The wall arrangement is designed so that warm heating water flows from the upper end into the space between the walls of the wall arrangement when heating water is drawn into the second chamber.

[0039] Figure 3schematically shows a heating system 100 in which an embodiment of the device for heating domestic water is installed. The heating system comprises a heat pump 101 with a heat exchanger 102 for heating heating fluid. In the situation shown here, heating fluid is pumped in a circuit through the heat pump 102 and heating circuits 103 by means of a pump 104. The cooled heating fluid, shown in the lines as black with white dots, can flow into and out of the second chamber 20 in this way, as indicated by the arrow within the second chamber. In the embodiment shown here, the first and second chambers are formed within a cylindrical boiler with a dished bottom and lid.A partition plate separates the two chambers, with the walls of the wall arrangement passing through the partition plate and the partition plate being continued inside the inner wall by another plate.

[0040] Figure 4 shows the embodiment from Figure 3In the operating state, the first chamber is charged with warm water. The first switching valve 105 is set in this operating state so that the outlet of the heat exchanger 102 of the heat pump is fluid-dynamically connected to the supply opening 11 of the first chamber. In the embodiment shown here, the warm heating water is filled into the first chamber via a single-layer device. Depending on the temperature of the heating water, the heating water exits the openings in the equally warm layer. The single-layer device ensures a low flow velocity, so that turbulence of the established layers is largely avoided. The second switching valve 106 is set so that the intake side of the pump 104 is fluid-dynamically connected to the discharge opening 12 of the first chamber. In this way, the coldest water is sucked out of the first chamber. The active lines in this and the following figures are analogous to the Figure 3Again, this is highlighted graphically as black with white dots for cold water and as white with black dots for hot water. In this operating condition, a typical temperature of 45°C can be achieved at the upper, i.e., warm, end of the first chamber, while a typical temperature of 30°C is reached in the second chamber.

[0041] Figure 5 again shows the same embodiment of the device as in Figure 3, now in the operating state of drawing heated domestic water. The first switching valve 105 is set so that the outlet of the heat exchanger 102 is fluid-dynamically connected to the supply opening 11 of the first chamber. The second switching valve 106 is set so that the suction side of the pump 104 is fluid-dynamically connected to the withdrawal opening of the second chamber. As indicated by arrows, in this operating state the warmest water from the uppermost layer in the first chamber is sucked into the space between the walls of the wall arrangement. There it flows along the turns of the helically laid pipe arrangement and releases heat energy to the domestic water in the pipe arrangement. Heating of the domestic hot water DHW to a temperature close to below the temperature of the warmest layer in the first chamber, e.g. 1 Kelvin to 2 Kelvin below the temperature of the warmest layer, is achievable in this way.The inventor is not aware of any other arrangement with which such a small temperature difference Delta T can be achieved in domestic hot water preparation. The heating water, cooled by contact with the pipe arrangement, flows into the second chamber, from where it is sucked off via pump 104 and pumped further into the heat exchanger of the heat pump. Cold domestic water flows in through inlet opening 31 and is preheated in a first stage within the second chamber. In this way, residual heat from the heating water from the heating circuits can be efficiently utilized, since cold domestic water typically has a temperature of 10°C to 15°C, thus being significantly colder than the returning heating water from the heating circuit. The domestic water, subsequently mentioned in the second stage in the first chamber, is taken from the outlet opening 32.

[0042] Figure 6 shows an embodiment which, compared to the device according to Figure 3 , additionally has a heat exchanger for a thermosolar heat source in the first chamber. The solar heating operating mode possible in this embodiment is shown. The heat pump 101 is not in operation in this operating mode. The temperature in the first and second chambers is now determined by the thermosolar heating and can be up to 90°C. The two switching valves 105 and 106 are connected so that hot heating water is drawn from the first and second chambers and pumped through the inactive heat exchanger of the heat pump into the heating circuits.

[0043] Figure 7 shows details of an embodiment of a single-layer device in different views. Fig. 7.a)shows a perspective, transparent view showing an outer, upright cylinder and, within it, an inner, upright cylinder. The heating water is supplied through the shorter, horizontally arranged pipe section.

[0044] Holes in the inner cylinder are visible in this transparent representation. Fig. 7.b) shows a side view, Fig. 7.c) a front view showing the outward-facing openings in the outer cylinder. Fig. 7.d) shows a section along the plane AA, whose position in Fig. 7.c) is marked.

[0045] Figure 8 shows an embodiment of the heat exchanger arrangement with two walls, which are designed as inner and outer cylinders, and wherein section 33 of the line arrangement lying between the walls is arranged spirally around the inner cylinder. Fig. 8.a)shows a side view, with only the outer wall visible. Fig. 8.b) shows a section through the heat exchanger arrangement. Fig. 8.c) shows a side view with the outer wall removed so that the windings of the cable arrangement are visible.

[0046] Figure 9 shows in four different views an illustrative model of a heat exchanger arrangement in a more specific embodiment than in Figure 8, namely with a line arrangement 33 in the form of a corrugated pipe, which can be made of stainless steel. The inner 40' and outer wall 40'' can, for example, consist of a plastic that can withstand temperatures up to 90°C. Examples of materials that can be used are PVC-U, i.e. heat-resistant PVC (unplasticized rigid PVC), or PPs, i.e. heat-resistant polypropylene. Not part of the heat exchanger arrangement, and only provided here to visualize the spirally laid corrugated pipe, are the circular holes in the outer wall. As in Fig. 9.c)As can be clearly seen, thanks to the numerous troughs in the outer surface of the corrugated pipe, a cross-section remains open between the inner wall, outer wall, and corrugated pipe, allowing heating water to flow around the coils of the pipe arrangement in the longitudinal direction of the two cylindrical walls. In addition, flow along the coils, i.e., tangential to the cylinders, is possible.

[0047] Figure 10 shows an embodiment of the device in which a particularly efficient first stage of the heat exchanger is formed in the second chamber. Openings and closures in the wall arrangement in the second chamber are designed in such a way that a fluid-dynamic series connection with the analogous arrangement in the first chamber results. Fig. 10.b) shows an enlarged detail from Fig. 10.a)Arrows indicate the flow of heating water during domestic hot water extraction. Additionally, other optional elements are shown here, which can be combined with other designs regardless of the specific wall configuration. These include a heating element, which can be powered, for example, by electricity from a photovoltaic system, and a heat exchanger for a thermosolar heat source, as already discussed in connection with another design.

[0048] Figure 11 shows the inner wall, pipe arrangement and outer wall elements arranged side by side, so that the features of the individual elements are easier to recognize. In the assembled heat exchanger, the elements are similar to the simpler version of Figure 8 arranged essentially coaxially to each other. Fig. 11.a) shows the elements in perspective view, Fig. 11.b) in a front view, Fig. 11.c)shows the elements in plan view, with the bearings of a section plane AA marked, and Fig. 11.d) shows a cross section through plane AA from Fig. 11.c) . The embodiment shown here has two sections of the line arrangement, which are respectively located in the first and second chamber of the device, as shown in Figures 10.a) and 10.b) The outer wall element is made up of several parts, so that the heat exchanger can be assembled from both sides of a separating plate between the two chambers. Openings in the inner wall ensure a flow during operation, as shown in Fig. 10.b) The spiral-shaped line arrangement can also be used as a corrugated pipe, as in Fig. 8 illustrated, trained.

[0049] Figure 12shows an embodiment of the single-layer device in the form of a layered tube. Such a single-layer device can be used within the scope of the present invention, but also independently of the device according to the invention, in known layered storage containers for layering heating fluid according to the temperature of the layers. Fig. 12.a) shows a side view in which the position of section planes AA and CC is marked. Fig. 12.b) shows a section through the section plane AA from Fig. 12.a) The heating fluid inlet leads into the centrally and horizontally aligned cylinder, which has a plurality of holes in its wall. Within this cylinder, steel wool (not shown here) can be arranged as an additional barrier element. In this case, a filter can surround the steel wool to retain any steel particles. Fig. 12.c) shows a section along the plane CC. Fig. 12.d)"Detail D" shows an enlarged version of this section. Here, the openings in the inner and outer walls are visible, as well as the flow path of the heating fluid from the interior space within the inner wall, through an opening into the space between the walls, and through an opening in the outer wall. This flow pattern leads to a calming of the flow of the heating fluid. Fig. 12.e) shows in "Detail B" a section of Fig. 12.b) in enlarged form. Here, too, arrows indicate the flow of heating fluid through the openings.

[0050] Figure 13shows a schematic representation of an embodiment of the heating system in the "heat pump defrosting" operating mode. On cold days, the heat pump's outdoor heat exchanger may freeze. After switching the heat pump's function, the defrost circuit shown here can be used to allow the heat pump to extract heat from the heating fluid in the heating circuit, thereby defrosting the outdoor heat exchanger (not shown here).

[0051] Figure 14 shows a schematic representation of a heating system in "anti-stagnation mode." In the case of high solar radiation, overheating of the solar circuits can occur in the version with thermo-solar heating. In the operating mode shown here, the heat pump can be operated in such a way that heat energy is extracted from the heating fluid and released via the heat pump's external heat exchanger (not shown).

[0052] Figure 15 shows a schematic representation of an embodiment of the heating system in a first variant of the "cooling air conditioning" operating mode. In this variant, the heating fluid is routed through fan coils connected in parallel to the heating circuits. This serves to dehumidify the system. The heating circuits can be included for cooling air conditioning until the dew point is reached. The heat pump is configured to cool the heating fluid.

[0053] Fig. 16A schematic representation of an embodiment of the heating system in a second variant of the "cold air conditioning" operating mode. Unlike the cold air conditioning according to the first variant mentioned above, here the fan coils and heating circuits are connected in series. The first stage is used for dehumidification, while the second stage includes the heating circuits up to the dew point. The fan coils can also be bypassed in this arrangement using a reversing valve.

[0054] Overall, the present invention, specifically the specific device for heating domestic hot water, enables the operation of a circuit with a single pump. The various embodiments of the heating systems shown in the figures and their operating modes illustrate how flexible and versatile the same core component with a single pump can be. List of reference symbols

[0055] 1Device for heating domestic hot water 10First chamber 11Supply opening for heating fluid 12Discharge opening for heating fluid 13Connection opening to the second chamber 14High-temperature layer 15Medium-temperature zone 16Low-temperature layer 17Possible flow direction of heating fluid 18Interior (of the first chamber) 19Stratification direction (= direction of gravity during operation) 20Second chamber 21Supply opening for heating fluid 22Discharge opening for heating fluid 25Baffle plate (optional) 30Pipe arrangement for domestic water 31Inlet opening for cold domestic water 32Outlet opening for hot domestic water 33Section of the pipe arrangement 34Flow direction of domestic water 40Wall arrangement 40',40''Walls (of the wall arrangement) 41Inner cylindrical wall 42Outer cylindrical wall 50Single-layer device 51Opening to the interior of the first chamber 52Restriction element 53Boreholes (in inner pipe of the single-layer device) 54Flow damping element 100Heating system 101Heat pump 102Heat exchanger (of the heat pump) 103Heating circuit 104Pump 105First reversing valve 106Second reversing valve,

Claims

1. A device (1) for heating domestic water by thermal contact with a heating fluid, the device comprising a first chamber (10) and a second chamber (20) fluid-dynamically connected to the first chamber via a connecting opening (13), both the first chamber and the second chamber each having a supply opening (11, 21) and a removal opening (12, 22) for heating fluid, the first chamber being designed to store heating fluid in its interior (18) in layers (14, 15, 16) lying one above the other in a stratification direction (19) according to the temperature of the heating fluid, a conduit arrangement (30) for conducting domestic water, starting from an inlet opening (31) for cold domestic water, into the second chamber, through the second chamber, through the first chamber, and to an outlet opening (32) for heated domestic water,and wherein a wall arrangement (40) within the first chamber is designed such that heating fluid can be passed from a high-temperature layer (14) between walls (40', 40''; 41, 42) of the wall arrangement, flowing around a section (33) of the line arrangement in this way, and through the connecting opening (13) into the second chamber.

2. Device (1) according to claim 1, wherein the supply opening (11) of the first chamber is fluid-dynamically connected to the interior of the first chamber through a single-layer device (50), and wherein the single-layer device has openings (51) to the interior of the first chamber that are spaced apart from one another in the layering direction (19).

3. Device (1) according to claim 1 or 2, wherein the wall arrangement (40) comprises an inner (41) and an outer (42) cylindrical wall which are arranged coaxially to one another, and wherein the line arrangement (30) extends helically in a section (33) between the inner and the outer cylindrical wall.

4. Device (1) according to one of claims 1 to 3, wherein the line arrangement (30) is at least partially designed as a corrugated pipe.

5. Device (1) according to one of claims 2 to 4, wherein at least one obstruction element (52) within the single-layer device (50) blocks a direct path from the supply opening for heating fluid to the openings (51).

6. Device (1) according to claim 5, wherein the single-layer device (50) comprises an outer tube and an inner tube arranged coaxially therein as a hindrance element (52), wherein said plurality of openings (51) to the interior of the first chamber are arranged in the outer tube on a first side, and wherein bores (53) in the inner tube lead from an inside of the inner tube into a space between the inner tube and the outer tube, wherein the bores are opposite the first side with respect to a common axis of the two tubes.

7. Device according to one of claims 2 to 6, wherein the single-layer device (50) comprises a flow damping element (54), in particular designed as a pipe section filled with steel wool.

8. Device according to one of claims 1 to 7, additionally comprising a heat exchanger in the first chamber with connections leading out of the first chamber for connection to a thermosolar heat source.

9. A heating system (100) comprising a heat pump (101) with a heat exchanger (102), a pump (104) connected in series with the heat exchanger (102) for pumping the heating fluid, a heating circuit (103) for heating a building, and a device (1) according to one of claims 1 to 8, wherein an outlet of the heat exchanger is fluid-dynamically connectable via a first switching valve (105) selectively to the heating circuit (103) or to the supply opening (11) of the first chamber, wherein a suction side of the pump is fluid-dynamically connectable via a second switching valve (106) selectively to the removal opening (12) of the first chamber or the removal opening (22) of the second chamber, and wherein a return flow connection fluid-dynamically connects the heating circuit to the supply opening of the second chamber.

10. Operating method for operating a heating system according to claim 9, wherein the following operating states are set alternately: a) Heating operating state, wherein the first switching valve is set so that the outlet of the heat exchanger is fluid-dynamically connected to the heating circuit and wherein the second switching valve is set so that the suction side of the pump is fluid-dynamically connected to the discharge opening of the second chamber; b) Charging the first chamber with warm water operating state, wherein the first switching valve is set so that the outlet of the heat exchanger is fluid-dynamically connected to the supply opening (11) of the first chamber and wherein the second switching valve is set so that the suction side of the pump is fluid-dynamically connected to the discharge opening of the first chamber;c) Operating state of withdrawal of heated domestic water, wherein the first switching valve is set so that the outlet of the heat exchanger is fluid-dynamically connected to the supply opening (11) of the first chamber, wherein the second switching valve is set so that the suction side of the pump is fluid-dynamically connected to the withdrawal opening of the second chamber and wherein cold domestic water flows in through the inlet opening (31) and heated domestic water is withdrawn from the outlet opening (32); 11. Operating method according to claim 10, wherein the device (1) is a device according to claim 7, wherein a thermosolar heat source is connected to the heat exchanger in the first chamber, and wherein in addition a further operating state can be set: d) heating with solar operating state, wherein the heat pump (101) is not in operation, wherein the first switching valve is set such that the outlet of the heat exchanger is fluid-dynamically connected to the heating circuit and wherein the second switching valve takes on a mixer function so that the suction side of the pump is fluid-dynamically connected to the extraction opening of the first chamber and at the same time to the extraction opening of the second chamber.

12. Single-layer device (50) for the device (1) according to one of claims 2 to 8.

13. Heat exchanger arrangement for the device according to one of claims 1 to 8, wherein the heat exchanger arrangement comprises walls (40', 40''; 41, 42) and at least one section (33) of the line arrangement lying between the wall elements.

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