Hot water station

Abstract

The invention relates to a hot water station (50, 51, 52) for providing hot drinking water, said hot water station comprising: a water inlet (55) to which a hot water line can be connected; a water outlet (57) for providing hot water, to which a pipeline or a fitting can be connected; and a water reservoir (60) which is coupled between the water inlet (55) and the water outlet (57) and is designed to store water, wherein the water storage tank (60) comprises a heat exchanger (64) having a primary circuit (100) which is designed for water to flow therethrough and a secondary circuit (200) which has phase change material and is designed to store thermal energy as latent heat from hot water in the primary circuit (100) and to release thermal energy, which has been stored as latent heat, into cold water in the primary circuit (100).

Description

[0001] HOT WATER STATION

[0002] The invention relates to a hot water station for providing hot drinking water.

[0003] A hot water station is used in a hot water system to provide and distribute hot water. A typical hot water system consists of a drinking water heater with a hot water storage tank for the heated water and one or more draw-off points to which hot water flows from the drinking water heater through a pipe system. The hot water station is typically used as a hot water transfer point between pipes from the drinking water heater and pipes to the drinking water draw-off points.

[0004] Long pipe runs mean that delivering hot water from the drinking water heater to the draw-off points can be significantly time-consuming. If no water is drawn for an extended period, the water stagnates in the pipe system and cools down. This cold water must first drain away before hot water is available again at the draw-off points. Water stagnating in the pipe system for an extended period can lead to hygiene problems if waterborne bacteria, such as Legionella, multiply rapidly.

[0005] In conventional piping systems with long pipe runs, a circulation pipe is provided for reasons of comfort and hygiene. This ensures that hot water circulates in the pipe system and thus always flows past or close to the draw-off points, so that hot water is available at the draw-off points immediately or after a short time. If the circulating hot water is at a sufficiently high temperature, water bacteria are killed, thus reducing hygiene problems. However, a pump is required for the circulation, which consumes the same energy as heating the circulating hot water. Heating the constantly circulating drinking water to approximately 60 degrees Celsius, with possibly only a short draw-off time, is complex and involves thermal losses and electrical expenditure. A circulation-free hot water system, which does not require a circulation pipe, is more energy-efficient.For hygiene reasons, the volume in the pipes between the drinking water heater and the draw-off points should be kept low to ensure minimal water stagnation. Maximum values ​​for the volume in the pipes may be prescribed by law or building regulations. If the volume in the pipes between the drinking water heater and at least one of the draw-off points exceeds 3 liters, a circulation line or temperature-maintaining strips are mandatory for hygiene reasons, according to German legal requirements.

[0006] Additionally, a hot water system without a circulation line offers less comfort. If the water in the pipes has already cooled down, it must first drain away at the tap before warm water from the drinking water heater is available at the tap after some time.

[0007] DE 295 03 746 U1 describes a device for heating cold water in a pipe between a hot water generator and a hot water tap. The energy is stored in a heat storage unit as latent heat, i.e., conversion enthalpy.

[0008] The objective is to provide a device that offers greater convenience when drawing hot water. This objective is achieved by a hot water station having the features of claim 1.

[0009] The hot water station for providing hot drinking water is provided with a water inlet to which a hot water pipe can be connected, a water outlet for providing hot water, to which a pipe or fitting can be connected, and a water storage tank coupled between the water inlet and the water outlet and configured to store water. The water storage tank comprises a heat exchanger with a primary circuit configured for water to flow through it, and a secondary circuit with phase-change material configured to store thermal energy as latent heat from the water in the primary circuit and to release thermal energy stored as latent heat into the water in the primary circuit.

[0010] Hot water is heated drinking or service water in the temperature range of typically 30°C to 60°C, especially 45°C to 60°C. The heated water is also referred to as warm water below. The cooled, previously warm water in the hot water system is also referred to as cold water. It can be cooled to ambient temperature. Thermal energy of warm water, which has a temperature higher than the melting temperature of the phase-change material, is stored as latent energy in the phase-change material. The stored latent heat is transferred to cold water, which has a temperature lower than the melting temperature of the phase-change material, and heats it.

[0011] The hot water station can be advantageously used in a hot water system without a circulation line. It stores hot water decentrally and is positioned closer to the draw-off points than a hot water tank in a domestic hot water heater, thus reducing the time until hot water is available at the draw-off points. Nevertheless, it can also be used in a hot water system with a circulation line, as this also shortens the time until hot water is available at the draw-off points.

[0012] In one embodiment, the hot water station is a hot water transfer point and is connected via at least one supply line to the drinking water heater that feeds the hot water station. At least one distribution line leads from the hot water station to the draw-off points. The hot water station is provided with a water inlet and a water outlet for connecting these lines. Although a hot water line can be installed at the water inlet, cold water that has cooled down in the line, for example, can also flow through the line into the water tank of the hot water station. Even if the heating function of the drinking water heater has failed, only cold water would be available. Water is supplied through the water outlet. Although hot water is intended to be supplied, there are also operating states in which cold water is initially supplied at a temperature lower than a desired delivery temperature.This can be particularly the case when starting up the hot water station and after a long period of non-use. One or more distribution lines to the draw-off point(s) are installed at the water outlet. The installation of a fitting, such as a faucet, is also conceivable.

[0013] The water tank of the hot water station serves as a decentralized buffer in the hot water system, providing hot water closer to the draw-off points. The water tank is advantageously used to store hot water. Nevertheless, there are operating conditions in which it contains cold water that has cooled down in the tank or flowed in as cold water through the water inlet. The water tank has a capacity of 10 liters or less in one design, and in particular a capacity of 5 liters or less. The water tank can be bypassed by a bypass valve if sufficient hot water has already been stored. However, a regular flow of hot water also advantageously ensures the regular recharging of the phase-change material, which acts as a thermal storage device.

[0014] The heat exchanger enables the transfer of thermal energy between the materials in the primary and secondary circuits without causing any mixing. The component that separates the materials advantageously has good thermal conductivity and a large surface area. The water flowing through the hot water station flows through the primary circuit.

[0015] The heat exchanger comprises a phase-change material (PCM). The secondary circuit contains the phase-change material, which stores a large portion of the thermal energy supplied to it from the primary circuit in the form of latent heat during a phase change. In one design, the heat exchanger is operated with a phase change from solid to liquid and vice versa. Since the material neither flows in nor out of the secondary circuit, the heat exchanger can also be referred to as a (latency) heat storage device.

[0016] Flowing and / or stored hot water with a temperature higher than the melting temperature of the phase change material causes the phase change material to change phases, so that the melting phase change material stores some of the thermal energy of the hot water during the phase transition. Nevertheless, especially with flowing hot water, water is still available at the draw-off point at a temperature sufficient for hot water. The phase change material can, for example, be wax-like in its solid state and liquefy when heat is applied. The phase change material can, for example, comprise salt hydrates, salts, or organic substances such as paraffin and fatty acids. If no water has been drawn off for an extended period, the heat stored in the phase change material is used to reheat the water, which has cooled below its melting temperature, when the phase change material solidifies.The phase change material solidifies and releases the thermal energy released back into the stored water.

[0017] Advantageously, the melting point of the phase change material is above a predetermined minimum output temperature of the hot water delivered. The minimum output temperature describes a desired operating parameter. The minimum output temperature depends on the requirements for hot water use in the home and does not necessarily have to be perceived as hot by the user, but can also be perceived as lukewarm. An example minimum output temperature is approximately 40 degrees Celsius. A typical predetermined output temperature range that the hot water delivered should have is between 40 and 60 degrees Celsius, in particular between 45 and 60 degrees Celsius, which is a sufficient temperature for hot water use in the home. The hot water flowing into the water inlet is also advantageously within this temperature range.The melting point of the phase-change material is advantageously between 40 and 50 degrees Celsius, particularly between 42 and 48 degrees Celsius, so that incoming hot water melts the phase-change material. The same applies to water heated in the hot water station. The phase transition during solidification occurs within the desired discharge temperature range, particularly above the minimum discharge temperature, so that cooling water in the primary circuit or incoming cold water causes the phase-change material to solidify and the secondary circuit to discharge, which inhibits cooling or heats the cold water, respectively. In one embodiment, the hot water station is designed to heat the stored water electrically.The hot water heated by the hot water station can have the same temperature range as the hot water provided by the hot water tank; however, the hot water station can be designed to heat the water to a higher temperature, for example 60 degrees Celsius.

[0018] Electrical heating can support the provision of hot water by reheating the stored water after it has cooled below a predetermined threshold, for example the minimum discharge temperature, to counteract the cooling, so that warm water is always available in the water tank for withdrawal. This can be repeated several times. The energy required for this is significantly lower than if no phase change material were provided. Heating at a predetermined time, for example in the morning, ensures that hot water is available when it is typically needed. The interaction of warm water and phase change material described above also occurs when the water in water tanks is heated electrically. The thermal energy added to the water in this way is also stored in the heat exchanger.

[0019] One embodiment of an electric heating device for heating is designed to heat stored water that has cooled in the water tank or flowed into the water tank as cold water. The incoming cold water may have cooled in the pipes or originate from a defective drinking water heater. The stored water is advantageously heated electrically to at least 55 degrees Celsius, in particular at least 60 degrees Celsius, so that it is available and / or stored as hot water. In one embodiment, the water tank comprises thermal insulation that slows down the cooling of the stored hot water. Thermal insulation is also referred to as heat insulation. This thermal insulation can be configured so that the hot water remains sufficiently warm for at least 24 hours, i.e., it is warmer than a predetermined minimum discharge temperature.Especially when combined with prior electrical heating, the hot water stays warm enough for distribution. The thermal insulation can be located on the outside of the water tank and comprise insulating material.

[0020] In one embodiment of the heat exchanger, several primary circuits are provided which are thermally coupled to the secondary circuit. For example, a first and a second primary circuit can be provided which are separated from each other so that no water exchange takes place between the two primary circuits. Each primary circuit can transfer thermal energy to the secondary circuit so that the phase change material melts, and thermal energy from the secondary circuit can be transferred to the primary circuits upon solidification. The secondary circuit is designed to store thermal energy as latent heat from warm water in the first and / or second primary circuit and to release thermal energy that has been stored as latent heat to cold water in the first and / or second primary circuit. This concept is not limited to two primary circuits; more than two primary circuits can be provided that are thermally coupled to the same secondary circuit.

[0021] The hot water station design with two primary circuits in the heat exchanger combines the functionality of two hot water stations, providing drinking water for two hot water branches, for example, for the bathroom and kitchen of an apartment. For example, a long shower with hot water drawn from one hot water branch can cause thermal energy to be stored in the heat exchanger, which is then released for water drawn from the other hot water branch in the kitchen. This design offers an additional increase in efficiency, because drawing hot water from one of the primary circuits thermally charges the phase-change material acting as a storage device, and this charged energy storage is also available to the other primary circuit.

[0022] In one embodiment, the heat exchanger is designed as a plate heat exchanger. Alternatively, it can comprise finned tubes or an aluminum body, particularly with a large surface area. This provides considerable freedom in the design of the heat exchanger. Alternatively, in one embodiment, one or more, in particular two, hollow cylindrical chambers with phase-change material can be provided for the secondary circuit, and one or more, in particular two, hollow cylindrical water chambers for the primary circuit. The chambers for the primary and secondary circuits are arranged alternately, so that the hollow cylindrical chambers are nested within one another.

[0023] A pressure regulator can be provided in the hot water station to reduce the pressure of the incoming water at the water inlet if it is supplied at high pressure. High pressure can be used in the hot water system to bridge long pipe runs with small cross-sections without a circulation line. The operating pressure of one exemplary hot water station is permanently in the range of 6 bar, with pressure surges of up to 10 bar possible.

[0024] In one embodiment, the water storage tank is designed as a small water storage tank with a capacity of 2 liters or less, in particular with a capacity of 1 liter or less and in particular with a capacity of 0.5 liters or less. With such a water storage tank, the hot water station is not used as a transfer point, but as a miniature storage station for providing hot water in the immediate vicinity of the draw-off station. The miniature storage station is a compact, small hot water station, which is designed, for example, as an under-sink hot water station for installation under a sink. The less water is stored, the more compact it is. In a hot water system, the optional miniature storage station increases convenience in terms of the hot water preparation time, which is reduced by a further few seconds.

[0025] The micro-storage station advantageously includes thermal insulation to slow the cooling of the water. A heating device is also advantageously provided in the micro-storage station.

[0026] Below, some examples are explained in more detail using the drawings. They show:

[0027] Figure 1 shows schematically an embodiment of a hot water system,

[0028] Figure 2 shows schematically an embodiment of a hot water station,

[0029] Figure 3 shows schematically a section of an embodiment of a heat exchanger,

[0030] Figure 4 shows schematically a section of another embodiment of a heat exchanger,

[0031] Figure 5 schematically shows another embodiment of a hot water system, Figure 6 schematically shows another embodiment of a hot water station,

[0032] Figure 7 schematically shows a section of yet another embodiment of a heat exchanger,

[0033] Figure 8 schematically shows a section of yet another embodiment of a heat exchanger,

[0034] Figure 9 is a three-dimensional representation of another embodiment of a hot water station,

[0035] Figure 10 is a three-dimensional representation of a base area of ​​the hot water station,

[0036] Figure 11 is a schematic representation of a head section of the hot water station,

[0037] Figure 12 is a three-dimensional representation of the head area of ​​the hot water station, and

[0038] Figure 13 is a sectional view of the hot water station.

[0039] In the figures, identical or functionally equivalent components are provided with the same reference numerals.

[0040] Figure 1 schematically shows an embodiment of a hot water system with two hot water stations 51, 52. The hot water system comprises a drinking water heater 1 with a hot water tank 3 and, for example, a first and a second hot water station 51, 52 and four withdrawal stations 71, 72, 73, 74. The drinking water heater 1 heats cold drinking water flowing into the hot water tank 3 via a house connection 21 and stores it in the hot water tank 3 for withdrawal. A typical temperature of the hot water in the hot water tank 3 is 52 degrees Celsius. The heating is carried out, for example, by a heat exchanger of a heat pump or a gas boiler, but is not limited to these heating means.

[0041] A piping system 9 without circulation lines is provided between the drinking water heater 1 and the extraction stations 71, 72, 73, 74. This system is designed to allow hot water to flow from the hot water tank 3 of the drinking water heater 1 to the extraction stations 71, 72, 73, 74. At the extraction stations 71, 72, 73, 74, the hot water can be extracted and drained from the hot water system. The extraction stations 71, 72, 73, 74 can be configured, for example, as a shower or faucet. Two of the withdrawal stations 71, 72 and 73, 74 are each coupled to one of the hot water stations 51, 52, so that the water flows from the drinking water heater 1 to the withdrawal stations 71, 72 and 73, 74 through the first and second hot water stations 51, 52, respectively.

[0042] The hot water stations 51, 52 are hot water transfer points and are each connected to the drinking water heater 1 via supply lines 11. Distribution lines 13 lead from the hot water stations 51, 52 to the extraction stations 71, 72, 73, 74. Several connections can be made to the hot water stations 51, 52 for distribution lines 13 to extraction stations 71,

[0043] 72, 73, 74 may be provided. Several withdrawal stations are advantageously installed in a row, as shown in Figure 1, so that the distribution line 13 is looped to the most distant withdrawal station 72, 74 through further withdrawal stations 71, 73. The line volume in the pipes of each line route from the drinking water heater 1 to one of the withdrawal stations 71, 72, 73, 74 is less than or equal to a predetermined maximum line volume. This exemplary embodiment of a hot water system is a small system within the meaning of the German Drinking Water Ordinance, for which the maximum line volume of each line route must be equal to or less than 3 liters. In addition, the volume of the storage tanks for drinking water in the system must be less than or equal to 400 liters. For such a small system, in contrast to a large system, the mandatory annual microbiological drinking water testing is not required.

[0044] The hot water system with two hot water stations 51, 52 can, for example, be designed for two small apartments, each with a hot water station 51, 52. For a two-person apartment, one hot water station is sufficient for the draw-off points in the kitchen and bathroom. Alternatively, the hot water system can be designed for a larger apartment for three to four people. One hot water station 51, 52 is then provided for each of the bathroom and kitchen and their draw-off points.

[0045] In a hot water system for multiple residential units, for example, in a multi-unit residential building or an apartment complex, more than two hot water stations 51, 52 are provided. It is desirable for the hot water system to be a small system without circulation pipes. This can also be achieved in a multi-unit residential complex with long pipe runs, with high water pressure and a small pipe cross-section.

[0046] In this exemplary embodiment, two hot water branches 10, 20 are provided, in which the water is guided through a supply line 11 and one or more distribution lines 13 to one or more extraction stations 71, 72 and 73, 74, respectively. In each hot water branch 10, 20, the water flows through one of the hot water stations 51, 52. On the one hand, hot water from the drinking water heater 1 is guided to a first and second extraction station 71, 72 in the first hot water branch 10, and on the other hand, hot water from the drinking water heater 1 is guided to a third and fourth extraction station 73, 74 in the second hot water branch 20. The hot water branches 10, 20 are separate, so that no water exchange takes place. They have separate supply lines 11 and separate distribution lines 13. In each of the hot water branches 10, 20, the pipe volume in the pipes of the pipe route is less than or equal to the specified maximum pipe volume of 3 liters.Cold water is supplied separately via pipes 19 for cold water and separately from the hot water system to the extraction stations 71, 72, 73, 74.

[0047] Warm drinking water from the drinking water heater 1, which flows into the supply lines 11 and distribution lines 13 upon withdrawal but is no longer withdrawn, cools down. At the next withdrawal, this cooled water must first drain away until warm water from the drinking water heater 1 is again available at the withdrawal stations 71, 72, 73, 74. The warm water stations 51, 52 shorten the time until warm water is available at the withdrawal stations by storing warm water and, advantageously, also being able to heat cold water.

[0048] Figure 2 schematically shows the structure of an exemplary embodiment of a hot water station 51, such as can be used in the exemplary hot water system from Figure 1 as the first and second hot water stations 51, 52. However, its use is not limited to such a hot water system.

[0049] The hot water station 51 has a water inlet 55 connected to the supply line 11 and a water outlet 57 connected to the distribution line 13, so that the hot water branch 10 runs through the hot water station 51. The arrows illustrate incoming water 111 and outgoing water 131. In this embodiment, an optional pressure regulator 31 is provided on the inlet side to reduce the pressure of the incoming water at the water inlet 55 if water is provided at high pressure. High pressure can be used in the hot water system to bridge long pipe runs with a small cross-section without a circulation line. In another embodiment, a pressure regulator can be installed upstream of the water inlet 31, if necessary.

[0050] The hot water station 51 comprises a water tank 60 designed to store water. To distinguish it from the large hot water tank 3 of the drinking water heater 1, this water tank 60 can also be descriptively referred to as a small hot water tank. The storage volume of the water tank 60 is smaller than that of the hot water tank 3 in the drinking water heater 1. A typical value is 5 liters. The storage volume of the water tank 60 does not count towards the pipe volume of the hot water system, which should be smaller than the maximum volume. However, the total volume of all water tanks in the system must be equal to or smaller than a maximum storage volume, namely 400 liters, for the hot water system to be considered a small system according to the German Drinking Water Ordinance.

[0051] The water tank 60 has thermal insulation 62, which significantly slows the cooling of stored warm water. Such thermal insulation 62 is arranged on the outside of the water tank 60. It can comprise insulating, heat-storing material.

[0052] The water reservoir 60 is designed to heat the water electrically. If there is cold water in the water reservoir 60, whether as cold water from the tap or because it has cooled down, it can be heated electrically. This means that warm water is available in the water reservoir 60, even if no water has been drawn for an extended period. Thus, in one exemplary embodiment, heating to 60 degrees Celsius is provided after an extended period of inactivity. Heating can occur, for example, as soon as the temperature of the stored water has dropped below a predetermined threshold, e.g., a predetermined minimum discharge temperature, until the temperature in the water reservoir 60 has risen above another predetermined threshold. This process can be repeated if the water temperature drops again. A heating element 66 is provided as a heating device for heating, which can have an exemplary power consumption of 100 watts.This value is significantly lower than the power consumption of an instantaneous water heater for heating water in a station.

[0053] The water storage tank 60 comprises a heat exchanger 64 with a primary circuit for the drinking water and a secondary circuit with phase change material, or PCM for short. Exemplary embodiments of the heat exchanger 60 are a plate heat exchanger, a heat exchanger with finned tubes, or with aluminum bodies with a large surface area. The phase change material stores a large portion of the thermal energy supplied to it from the primary circuit in the form of latent heat, which is absorbed during the phase change from solid to liquid. Latent heat is also referred to as transformation enthalpy; in this exemplary embodiment, sublimation and fusion enthalpy are relevant. The phase change can occur at a melting temperature of approximately 45 degrees Celsius. The phase change material can comprise, for example, salt hydrates, salts, or organic substances such as paraffin and fatty acids.The phase change occurs just below or within the desired delivery temperature range for the delivered hot water. Hot water flowing through and / or electrically heated by the hot water station causes a phase change of the phase change material and stores part of the thermal energy of the hot water. Nevertheless, even when hot water is drawn off, the thermal energy of which has been partially used for the phase change, sufficient hot water is made available at the draw-off stations 71, 72, 73, 74. If no water has been drawn off for a longer period of time, the thermal energy stored in the phase change material serves to prevent or slow down the cooling of the stored water. The phase change material solidifies when the water in the primary circuit is cold or cooling, and the thermal energy released is transferred to the stored water or flowing through it, heating it.

[0054] For example, water at approximately 50 degrees Celsius from supply line 11 can cause the phase transition of the phase-change material liquefying in this temperature range. Nevertheless, water at approximately 40 degrees Celsius can still be drawn from withdrawal stations 71, 72, 73, and 74 despite the phase change.

[0055] The combination of heat exchanger 64 with phase change material, heating device 66 and thermal insulation 62 significantly reduces the energy required to provide hot water near the draw-off stations 71, 72, 73, 74. Compared to an instantaneous water heater in a station, the energy requirement for the hot water station 51 is reduced to approximately one seventh. The thermal insulation 62 can maintain the water temperature for at least 24 hours, so that the hot water can be drawn off without reheating. The hot water station 50 can provide hot water at the draw-off stations 71, 72, 73, 74 after just 8 to 15 seconds. In addition, the lower pressure loss of a heat exchanger 64 designed as a plate heat exchanger enables a discharge rate of 15 liters / min.

[0056] The hot water station 51 with water tank 60 has exemplary dimensions of 540 x 300 x 82 mm. It weighs approximately 9 kg. 1" female thread connections are provided. Internal stainless steel piping with a 1 / 4" female thread connection is provided for on-site installation of the transfer point. The piping is available in one design as a raw or pre-assembled set. Alternatively, it can be pre-installed on the hot water station 51 upon delivery.

[0057] The hot water station 51 significantly shortens the time until hot water is available at the draw-off stations. Even shorter times until hot water is available are possible by providing optional mini-storage stations 80 at the draw-off stations 71, 72, 73, and 74.

[0058] Figure 1 shows that the draw-off stations 71, 72, 73, 74 in this embodiment of the hot water system each have a miniature storage station 80 in which hot water can be stored in the immediate vicinity of the outlet from the draw-off stations 71, 72, 73, 74. The miniature storage station 80 is a compact, small version of a hot water station. It can be designed, for example, as an under-sink storage station. Such an under-sink storage station can be discreetly installed under a washbasin or in a washbasin base cabinet. The miniature storage station 80 can typically store a maximum of 0.5 liters of water. The optional miniature storage station 80 increases convenience in terms of hot water preparation time. It is reduced to less than 8 seconds. 5 seconds is a typical value.

[0059] The miniature storage station 80 is constructed similarly to the hot water station 51 described in connection with Figure 2 and has a small water tank and advantageously also the other features described above, i.e., thermal insulation and a heating device, to provide hot water. The miniature storage station 80 includes thermal insulation to slow the cooling of the water. Advantageously, the miniature storage station 80 also includes a heating device, for example, with a heating element, and a heat exchanger with phase-change material, the operation of which has been described above. The electrical power consumption of the miniature storage station 80 is in the range of 50 watts.

[0060] The storage volume of the smallest storage station 80 is also not included in the pipe volume, which must be less than the maximum volume of 3 liters for the hot water system to be considered a small system. Since the storage capacities of the water storage tanks in the hot water stations 51, 52 and the smallest storage stations are not part of the pipe volume, the maximum pipe volume is not exceeded in this exemplary embodiment either. However, the storage volume of the smallest storage stations 80 is included in the total volume of all storage tanks in the system, which must be less than a maximum storage volume of 400 liters to be considered a small system.

[0061] The highly efficient serial water storage tank 60 in the hot water stations 51, 52, particularly in combination with the optional mini-storage stations 80, enables a significantly shorter time until the hot water is available at the draw-off stations 71, 72, 73, 74 than with a conventional hot water system.

[0062] The hot water stations 51, 52 with water storage tank 60 and the mini-storage stations 80 have very low electrical energy consumption, especially compared to a station with an instantaneous water heater. The power consumption of the optional mini-storage stations 80 and the hot water stations 51, 52 with water storage tank 60 is almost negligible compared to the power consumption of stations with instantaneous water heaters. This advantage is particularly evident in large systems with many hot water stations 51, 52 and thus also many residential units. Due to the low energy consumption, with an exemplary power consumption of 50 to 100 watts, the total grid connection power is significantly lower than that of a conventional system or a system with instantaneous water heaters in the stations.With multiple hot water stations 51, 52, a simultaneity lock to limit the number of simultaneously operating hot water stations 51, 52 is no longer required. Smaller cable cross-sections can be used for the power supply. Additional transformer stations are not required. This overall reduction in power supply costs also leads to reduced planning costs for the system, and in particular for the electrical supply.

[0063] Figure 3 schematically shows a section of an embodiment of a heat exchanger 64, which is designed as a plate heat exchanger. Such a heat exchanger 64 can be provided in the hot water station 51, 52 or in the micro-storage station 80. Phase-change material from the secondary circuit 200 and water from the primary circuit 100 are provided alternatingly between the plates. Warm water with a temperature above the melting point of the phase-change material transfers thermal energy to the secondary circuit 200 containing solid phase-change material, so that the phase-change material melts and latent heat from the warm water is stored in the molten phase-change material. When cold water with a temperature below the melting point is present in the primary circuit 100, thermal energy stored as latent heat in the phase-change material is transferred to the cold water in the primary circuit 100 when the phase-change material solidifies, heating it.

[0064] Figure 4 schematically shows a section of a heat exchanger 64, which, for example, has finned tubes 92 through which the water of the primary circuit 100 flows. Phase change material is provided outside the finned tubes 92 in the secondary circuit 200. The finned tube 92 is a tubular component with fins 94 on its outer side to increase the tube surface area. This improves the transfer of thermal energy between the interior and exterior of the tube. Advantageously, the finned tubes 92, in particular the fins 94, are made of a material with good thermal conductivity.

[0065] The design of heat exchanger 64 is not limited to the aforementioned embodiments. Good heat transfer, a large surface area for thermal energy transfer, and weight, given the preferred wall mounting, are all factors that play a role in the design. For example, another embodiment of heat exchanger 64 includes aluminum bodies with a large surface area.

[0066] Figure 5 schematically shows another embodiment of a hot water system. The following description focuses on differences from the previous embodiment in Figure 1 and the hot water station 51, 52 described in connection with Figures 2 to 4.

[0067] In this exemplary embodiment, two hot water branches 10, 20 are provided, through which, on the one hand, hot water from the drinking water heater 1 is piped to a first and second withdrawal station 71, 72 in the first hot water branch 10, and on the other hand, hot water from the drinking water heater 1 is piped to a third and fourth withdrawal station 73, 74 in the second water branch 20. Although the hot water branches 10, 20 are separate, so that no water exchange takes place, both run through the same hot water station 50. They have separate supply lines 11 and separate distribution lines 13. The hot water branches 10, 20 are constructed with looped-through installation and micro-storage stations 80 as in the previous exemplary embodiment. In each of the hot water branches 10, 20, the line volume in the pipes of the line path is less than or equal to the specified maximum line volume of 3 liters.

[0068] The two hot water branches 10, 20 run through two primary circuits 100, 102 of the heat exchanger 64 in the hot water station 50.

[0069] Figure 6 shows schematically an embodiment of a hot water station 50 which can be used in the hot water system described above.

[0070] As in the previous embodiment, the hot water station 50 comprises a water storage tank 60, thermal insulation 62, a heat exchanger 64, and a heating element 66 as a heating device. Since the hot water station 50 is designed for two hot water branches 10, 20, it has two water inlets 55 for the supply lines 11 and two water outlets 57 as connections for their distribution lines 13. With more than two primary circuits, fittings for the inlet and outlet would also be provided in multiples, but can be designed in the same way. The housing dimensions are also larger than in the previous embodiment, since the hot water station 50 stores more water to supply two hot water branches 10, 20. Optional pressure regulators 31 are provided on the inlet side.

[0071] The supply lines 11 are connected to the first and second water inlets 55, and the distribution lines 13 are connected to the first and second water outlets 57. Incoming and outgoing water 111, 131 of the first hot water branch 10 flows through the first water inlet 55 and outlet 57, respectively, and incoming and outgoing water 112, 132 of the second hot water branch 20 flows through the second water inlet 55 and outlet 57, respectively. There is no mixing of the drinking water between the hot water branches 10, 20. There is also no mixing in the hot water station 50. In addition to separate distribution lines 13, the hot water branches 10, 20 also have separate supply lines 11 that run between the drinking water heater 1 and the hot water station 50.

[0072] The secondary circuit of heat exchanger 64 comprises phase-change material and interacts with both primary circuits, allowing thermal coupling through the secondary circuit. Heat from each of the primary circuits can be stored in the secondary circuit and released from the secondary circuit to each of the primary circuits. This allows the phase-change material to be charged by one of the primary circuits, and then the stored thermal energy can be released to the other primary circuit.

[0073] Figure 7 schematically shows a section of the heat exchanger 64, which is embodied, for example, as a plate heat exchanger. Phase-change material of the secondary circuit 200 and the water of the first and second hot water branches 10, 20, which flows through the first and second primary circuits 100, 102, are provided between the plates in alternating flow. However, the water of the first primary circuit 100 flows through the plates spatially separated from the water of the second primary circuit 102, preferably along alternately arranged flow paths, so that the water in the first primary circuit 100 flows past the phase-change material between two adjacent plates on one side and the water in the second primary circuit 102 on the other side.As a result, the thermal energy stored in the phase-change material can be transferred from the secondary circuit 200 to both the first and second primary circuits 100, 102, even if the thermal energy storage was only caused by withdrawal in one of the primary circuits 100, 102. Nevertheless, both primary circuits 100, 102 can charge the phase-change material. For example, a shower, which typically involves withdrawing a large amount of hot water over a longer period of time from the first hot water branch 10, can cause thermal energy to be stored in the secondary circuit 200 in the first primary circuit 100. This energy can then be released for water withdrawal in the kitchen in the second hot water branch 20 via the second primary circuit 102, but also, for example, for washing hands in the bathroom, which is provided in the first hot water branch 10.

[0074] Figure 8 schematically shows a section of an embodiment of a heat exchanger 64 having finned tubes 92 through which the water from the primary circuits 100, 102 flows. There are first and second finned tubes through which water from the first and second primary circuits 100, 102 flows, respectively, without any fluid exchange. The tubes 92 are advantageously arranged alternately, so that a first tube is adjacent to second tubes, and vice versa.

[0075] The other features of the hot water station and their use, namely the thermal insulation and the heating of the stored water, which were previously described in connection with Figures 1 to 4, are also provided in the hot water station 50 in Figures 5 to 8 in order to heat the water in the hot water station 50 for both hot water branches 10, 20 and to slow its cooling. Thus, the thermal insulation 62 can keep the hot water sufficiently warm for use for up to 24 hours. This exemplary embodiment also features a 100-watt heating element 66, which can be used to heat the cooled water in the water tank 60 to 60 degrees Celsius after a prolonged period of inactivity.

[0076] The embodiment of the hot water station 50 described in connection with Figures 5 to 8 has the same advantages as the embodiment of the hot water station 51, 52 described in connection with Figures 1 to 4. In both hot water branches 10, 20, the output volume is equal to or below a predetermined value, in particular, it is equal to or less than three liters. The discharge capacity at the withdrawal stations 71, 72, 73, 74 is higher in the hot water station 50 at more than 20 liters / min due to the supply of the withdrawal stations 71, 72, 73, 74 by two hot water branches 10, 20. The drinking water supply is more powerful, although less energy is required. The planning and implementation for the use of hot water stations 50 in a hot water system is also simplified, since only one installation path is provided instead of two if two hot water stations 51, 52 were provided for the two hot water branches 10, 20.Even if the hot water station 50 has the same or similar power consumption of 100 W as in the previous embodiment, the provision of the thermal energy stored in the secondary circuit 200 for both primary circuits 100, 102 leads to an increase in efficiency.

[0077] Figure 9 shows another embodiment of a hot water station 50. The hot water station 50 has an elongated basic shape with two columns and front-end mounting areas 96, which are designed as foot-shaped extensions with a flat support surface. Fasteners, such as screws, can be passed through holes 97 in the mounting areas 96 to attach the hot water station 50, for example, to a wall.

[0078] A heat exchanger with phase-change material is provided inside a column-shaped main module 98. This is used to heat cooled water in chambers of the main module 98. The electrical system and cables connecting electrical components on both ends run in a protective tube 99 arranged longitudinally next to the main module 98. The hot water station 50 is more than one meter long, typically in the range of 1.5 meters.

[0079] The hot water station 50 has a first front area, which can also be referred to as the base area 81, and a second, opposite front area, which can also be referred to as the head area 82. The water from the drinking water heater 1 enters the base area 81 and exits to the draw-off stations 70, 71, 72, 73, 74. Connections for the supply of electrical components, communication, and control are provided in the head area 82. A heating device is also provided in the head area 82. It can, for example, be designed as a 50W heater with a heating element. The heating device is used when there is low draw-off and insufficient recharging of the phase change material. Sensor lines run in the protective tube 99 to volume flow meters in the base area 81, which record the water flow.

[0080] Despite the designations head and base area 82, 81, the orientation of the mounted hot water station 50 is not limited to the vertical orientation shown in Figure 9. The hot water station 50 can also be mounted upside down, horizontally, or at an angle, preferably in a flush-mounted installation.

[0081] Figure 10 shows the base area 81 of the hot water station 50 with the water inlet and water outlet of the hot water station 50, so that the water inlet and outlet occur at the same end, which simplifies installation. The water from the drinking water heater enters at the water inlet 55 and is led into an inner water chamber 151. It flows through the inner water chamber 151 to the head area 82 of the hot water station 50, where it is redirected into an outer water chamber 512, through which it flows back into the base area 81 to the water outlet 57, where the water is supplied to the draw-off stations 70, 71, 72, 73, 74.

[0082] Figure 11 schematically shows the interior of the hot water station 50 with a bypass chamber 84 in the head region 82 of the main module 98, through which the water flows from the inner to the outer water chamber 151, 152. The height of the bypass chamber 84 is in the range of 10 mm.

[0083] Figure 12 shows the head region 82 of the main module 98 with filling openings 85 in the bypass chamber 84. The main module 98 can be filled with phase change material through the filling openings 85. Inflow and outflow from the inner and outer water chambers 151, 152, respectively, occur through annular gaps 86.

[0084] Figure 13 shows a section through the hot water station 50 with main module 98 and protective pipe 99. In the main module 98, there are two chambers filled with phase change material, namely an inner chamber 201 and an outer chamber 202, as a secondary circuit, and an inner and outer water-carrying chamber 151, 152, which have a hollow cylindrical shape, as the primary circuit. The inner water chamber 151 is arranged between the two chambers 201, 202 with phase change material 250. The chambers 201, 202 with phase change material 250 have walls and internal structures 260 made of aluminum, which enables good heat transfer. The structures 260 enlarge the surface area of ​​the chambers 201, 202 and have a cross-section with radial webs that can be forked. An external chamber is a vacuum chamber 270 for thermal insulation, which encloses the chambers 201, 202 with phase change material 250 and the water chambers 151, 152.In the center of the inner chamber 201 with phase change material 250 is an electric heating element, which in one embodiment is approximately 200 mm long and is positioned in the head region 82 or adjacent to the head region 82.

[0085] The cooled water from the pipe first flows through the inner water chamber 151 and then through the outer water chamber 152. As the water flows through the water chambers 151, 152, it absorbs the heat stored in the phase change material 250, so that when it exits the hot water station 50, it has a temperature of approximately 45 degrees Celsius. After the cooled water has passed through the device and been heated by the phase change material 250, which has solidified in the process, warm water with a temperature of approximately 53 degrees Celsius flows from the hot water tank 3 and recharges the phase change material 250 by causing a phase change. If no hot water is drawn for an extended period, the phase change material 250 can be kept at temperature with little energy expenditure, preventing it from solidifying.

[0086] The features specified above, those in the claims, and those evident from the illustrations can be advantageously implemented both individually and in various combinations. The invention is not limited to the described embodiments, but can be modified in many ways within the scope of expert knowledge.

[0087] Reference symbol

[0088] 1 drinking water heater

[0089] 3 hot water tanks

[0090] 9 Pipeline system

[0091] 11 Supply line

[0092] 10, 20 hot water branch

[0093] 13 Distribution line

[0094] 19 Cold water pipe

[0095] 21 House connection

[0096] 31 pressure regulators

[0097] 50, 51 , 52 Hot water station

[0098] 55 Water inlet

[0099] 57 Water outlet

[0100] 60 water reservoirs

[0101] 62 Thermal insulation

[0102] 64 heat exchangers

[0103] 66 Heating element

[0104] 70, 71, 72, 73, 74 withdrawal station

[0105] 80 micro storage stations

[0106] 81 Base area

[0107] 82 head area

[0108] 84 Around streams comb

[0109] 85 Filling opening

[0110] 86 gap

[0111] 92 finned tube

[0112] 94 Rib

[0113] 96 Mounting area

[0114] 97 holes

[0115] 98 Main module 99 Protective tube

[0116] 100, 102 primary circuit

[0117] 111, 112 incoming water

[0118] 131, 132 flowing water 151, 152 water chamber

[0119] 200 secondary circuit

[0120] 201, 202 Chamber

[0121] 250 phase change material

[0122] 260 Structure 270 Vacuum Chamber

Claims

Claims:

1. Hot water station (50, 51, 52) for providing hot drinking water, comprising a water inlet (55) to which a hot water pipe can be connected, a water outlet (57) for providing hot water, to which a pipe or a fitting can be connected, and a water reservoir (60) coupled between the water inlet (55) and the water outlet (57) and designed to store water, wherein the water reservoir (60) comprises a heat exchanger (64) with a primary circuit (100) designed for water to flow through it, and a secondary circuit (200) with phase change material designed to store thermal energy as latent heat from the water in the primary circuit (100) and to release thermal energy that has been stored as latent heat to the water in the primary circuit (100).

2. Hot water station (50, 51, 52) according to claim 1, wherein a melting temperature of the phase change material is above a predetermined minimum discharge temperature of discharged hot water.

3. Hot water station (50, 51, 52) according to claim 1 or 2, wherein a predetermined delivery temperature range of delivered hot water is between 45 and 60 degrees Celsius.

4. Hot water station (50, 51, 52) according to claim 2 or 3, wherein the melting temperature of the phase change material is between 40 and 50 degrees Celsius, in particular between 42 and 48 degrees Celsius.

5. Hot water station (50, 51, 52) according to one of the preceding claims, which is designed to heat the stored water electrically.

6. Hot water station (50, 51, 52) according to one of the preceding claims, with an electric heating device (66) which is designed to heat stored water which has cooled in the water reservoir (60) or has flowed into the water reservoir (60) as cold water.

7. Hot water station (50, 51, 52) according to claim 5 or 6, which is designed to electrically heat the stored water to at least or equal to 55 degrees Celsius, in particular at least or equal to 60 degrees Celsius.

8. Hot water station (50, 51, 52) according to one of the preceding claims, wherein the water storage tank (60) comprises thermal insulation (62) which slows down the cooling of stored hot water.

9. Hot water station (50, 51, 52) according to claim 8, wherein the thermal insulation (62) comprises insulating material arranged on the outside of the water tank (60).

10. Hot water station (50, 51, 52) according to one of the preceding claims, wherein the primary circuit (100) is a first primary circuit (100) which is separate from a second primary circuit (102) of the heat exchanger (64).

11. Hot water station (50, 51, 52) according to claim 10, wherein the secondary circuit (200) has one or more hollow cylindrical chambers (201, 202) with phase change material and the primary circuit (100) has one or more hollow cylindrical water chambers (151, 152) which are nested within one another.

12. Hot water station (50, 51, 52) according to claim 10 or 11, wherein the secondary circuit (200) is designed to store thermal energy as latent heat from water in the first and / or second primary circuit (100, 102) and to release thermal energy that has been stored as latent heat into water in the first and / or second primary circuit (100, 102).

13. Hot water station (50, 51, 52) according to one of the preceding claims, wherein the heat exchanger (64) is designed as a plate heat exchanger or has finned tubes (92) or has an aluminum body.

14. Hot water station (50, 51, 52) according to one of the preceding claims, which is designed as a micro-storage station (80), wherein the water storage tank (60) has a capacity of 2 liters or less, in particular a capacity of 1 liter or less, and in particular a capacity of 0.5 liters or less.

15. Hot water station (50, 51, 52) according to one of the preceding claims, wherein the hot water station is designed as an under-sink hot water station.

Images