DE102022129808A1 - Hot water station - Google Patents

Abstract

Hot water station (50, 51, 52) for providing hot drinking water with 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) which is coupled between the water inlet (55) and the water outlet (57) and is designed to store water, wherein the water reservoir (60) comprises a heat exchanger (64) with a primary circuit (100) which is designed to have water flowing through it, and a secondary circuit (200) with phase change material which 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

The invention relates to a hot water station for providing warm drinking water.

A hot water station is used in a hot water system to provide and distribute hot water. A typical hot water system includes a drinking water heater with a hot water tank for the heated water and one or more extraction stations 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 extraction stations for the drinking water.

Long pipe runs mean that the provision of hot water from the drinking water heater to the extraction stations can take a significant amount of time. If no water is drawn off for a long time, 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 extraction stations. Water standing in the pipe system for a long period of time can lead to a hygiene problem if water bacteria, such as legionella, multiply rapidly.

In conventional pipe 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 extraction points, so that hot water is available at the extraction points immediately or after a short time. If the circulating hot water is at a sufficiently high temperature, water bacteria are killed, so that hygiene problems are reduced. However, a pump is required for the circulation, which consumes just as much energy as heating the circulating hot water. Heating the constantly circulating drinking water to around 60 degrees Celsius with possibly only a short tapping time during which water is drawn is complex and involves thermal losses and electrical expenditure. A circulation-free hot water system that does not require a circulation pipe is more energy-efficient. For hygiene reasons, the volume in the pipe runs between the drinking water heater and the extraction points should then be small, so that there is little water in the pipes. Maximum values for the volume in the pipes can be prescribed by law or by construction engineering. If the volume in the pipes between the drinking water heater and at least one of the extraction points is greater than 3 liters, a circulation pipe or temperature-maintaining bands are mandatory for hygienic reasons in accordance with the legal requirements in Germany.

In addition, a hot water system without circulation pipes offers less comfort. If the water in the pipes has already cooled down, it must first flow away at the extraction station before warm water from the drinking water heater is available at the extraction station after some time.

The task is to provide a device that offers more convenience when drawing hot water.

The problem is solved by a hot water station having the features of claim 1.

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 a fitting can be connected, and a water storage tank which is coupled between the water inlet and the water outlet and is designed to store water. The water storage tank comprises a heat exchanger with a primary circuit which is designed for the water to flow through it, and a secondary circuit with phase change material which is designed to store thermal energy as latent heat from the water in the primary circuit and to release thermal energy which has been stored as latent heat into the water in the primary circuit.

Hot water is heated drinking water or domestic water in the temperature range of usually 30 °C to 60 °C, in particular 45 °C to 60 °C. The heated water is also referred to below as warm water. The cooled, previously warm water in the hot water system is also referred to as cold water. It can be cooled down to the ambient temperature. Thermal energy of warm water that has a higher temperature 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 that has a lower temperature than the melting temperature of the phase change material and heats it.

The hot water station can be used advantageously in a hot water system without circulation pipes. It stores hot water decentrally and is positioned closer to the points of use than a hot water storage tank of the drinking water heater, so that the time until warm water is available at the extraction stations is reduced. Nevertheless, it can also be used in a hot water system with a circulation line, because in this case too the time until warm water is available at the extraction stations is reduced.

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 extraction points. The water inlet and the water outlet are provided on the hot water station to connect 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 provided through the water outlet. Although hot water is to be provided, there are also operating states in which cold water is initially delivered at a temperature lower than a desired delivery temperature. This can be the case in particular when starting up the hot water station and after a long pause in use. One or more distribution lines to the extraction point(s) are installed at the water outlet. The installation of a fitting, for example a water tap, is also conceivable.

The water tank of the hot water station serves as a decentralized buffer in the hot water system, which provides hot water closer to the extraction stations. The water tank is advantageously used to store hot water. Nevertheless, there are operating states in which it contains cold water that has cooled down in the tank or has flowed in as cold water through the water inlet. In one design, the water tank has a capacity of 10 liters or less, 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, regular flow of hot water also advantageously causes the phase change material acting as a thermal storage to be regularly charged.

The heat exchanger enables the transfer of thermal energy between the materials in the primary circuit and the secondary circuit without the materials 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.

The heat exchanger contains a phase change material, abbreviated to “PCM”. The secondary circuit contains the phase change material, which stores a large part of the thermal energy supplied to it from the primary circuit in the form of latent heat during a phase change. In one version, 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.

Hot water flowing through and/or stored at a higher temperature than the melting temperature of the phase change material causes a phase change of the phase change material, so that the melting phase change material stores some of the thermal energy of the hot water during the phase transition. Nevertheless, especially when hot water is flowing through, water with a temperature that is still sufficient for hot water is available at the extraction station. 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 a long time, the heat stored in the phase change material is used to reheat the water that has cooled below the melting temperature when the phase change material solidifies. The phase change material solidifies and releases the thermal energy released in the process back into the stored water.

Advantageously, the melting temperature of the phase change material is above a predetermined minimum delivery temperature of delivered warm water. The minimum delivery temperature describes a desired operating parameter. The minimum delivery temperature depends on the requirements for the use of hot water 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 delivery temperature is approximately 40 degrees Celsius. A typical predetermined delivery temperature range that delivered warm water should have is between 40 and 60 degrees Celsius, in particular between 45 and 60 degrees Celsius, which is a sufficient temperature for the use of hot water in the home. The water flowing into the water inlet is also advantageously in this temperature range. Hot water. The melting temperature of the phase change material is advantageously between 40 and 50 degrees Celsius, in particular between 42 and 48 degrees Celsius, so that incoming hot water causes the phase change material to melt. The same applies to water that is heated in the hot water station. The phase transition during solidification takes place in the area of the desired discharge temperature range, in particular 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.

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, it can be provided that the hot water station heats the water to a higher temperature, for example 60 degrees Celsius.

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 use. This can be repeated several times. The energy required for this is much 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.

One embodiment of an electric heating device for heating is designed to heat stored water that has cooled in the water tank or has flowed into the water tank as cold water. The incoming cold water can have cooled in the pipe or come 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 as hot water and/or is stored.

In one embodiment, the water tank includes thermal insulation that slows down the cooling of the stored warm water. Thermal insulation is also referred to as heat insulation. This thermal insulation can be designed so that the warm water stays warm enough for at least 24 hours, i.e. it is warmer than a predetermined minimum delivery temperature. In particular, in conjunction with previous electrical heating, the hot water stays warm enough for delivery. The thermal insulation can be arranged on the outside of the water tank and comprise insulating material.

In one embodiment of the heat exchanger, a plurality of 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 one another 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 when it solidifies. 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 which 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, but more than two primary circuits can be provided which are thermally coupled to the same secondary circuit.

The design of the hot water station with two primary circuits in the heat exchanger combines the functionality of two hot water stations, as it provides 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 when hot water is drawn from one of the primary circuits, the phase change material acting as a storage device is thermally charged, and this charged energy storage device is also available to the other primary circuit.

In one version, the heat exchanger is designed as a plate heat exchanger. Alternatively, it can have finned tubes or an aluminum body, especially with a large surface area. This results in many degrees of freedom for 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 circuit and secondary circuit are arranged alternately so that the hollow cylindrical chambers are nested within one another.

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 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 pipe. The operating pressure of an embodiment of a hot water station is permanently in the range of 6 bar, with pressure surges of up to 10 bar being possible.

In one embodiment, the water tank is designed as a small water 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 tank, the hot water station is not used as a transfer point, but as a micro storage station for providing hot water in the immediate vicinity of the extraction station. The micro storage station is a compact, small hot water station that is designed, for example, as an under-sink hot water station for installation under a washbasin. The less water that is stored, the more compact it is. In a hot water system, the optional micro storage station increases convenience in terms of the hot water preparation time, which is reduced by a further few seconds.

The small storage station advantageously includes thermal insulation to slow down the cooling of the water. A heating device is also advantageously provided in the small storage station.

• 1 schematisch ein Ausführungsbeispiel einer Warmwasseranlage,
• 2 schematisch ein Ausführungsbeispiel einer Warmwasserstation,
• 3 schematisch einen Ausschnitt aus einem Ausführungsbeispiel eines Wärmetauschers,
• 4 schematisch einen Ausschnitt aus einem weiteren Ausführungsbeispiel eines Wärmetauschers,
• 5 schematisch ein weiteres Ausführungsbeispiel einer Warmwasseranlage,
• 6 schematisch ein weiteres Ausführungsbeispiel einer Warmwasserstation,
• 7 schematisch einen Ausschnitt aus noch einem weiteren Ausführungsbeispiel eines Wärmetauschers,
• 8 schematisch einen Ausschnitt aus noch einem weiteren Ausführungsbeispiel eines Wärmetauschers,
• 9 eine dreidimensionale Darstellung eines weiteren Ausführungsbeispiels einer Warmwasserstation,
• 10 eine dreidimensionale Darstellung eines Sockelbereichs der Warmwasserstation,
• 11 eine schematische Darstellung eines Kopfbereichs der Warmwasserstation,
• 12 eine dreidimensionale Darstellung des Kopfbereichs der Warmwasserstation, und
• 13 eine Schnittdarstellung der Warmwasserstation.

Some examples of implementation are explained in more detail below using the drawing. They show:

• 1 schematically an embodiment of a hot water system,
• 2 schematically an embodiment of a hot water station,
• 3 schematically a section of an embodiment of a heat exchanger,
• 4 schematically a section of another embodiment of a heat exchanger,
• 5 schematically another embodiment of a hot water system,
• 6 schematically another embodiment of a hot water station,
• 7 schematically a section of yet another embodiment of a heat exchanger,
• 8th schematically a section of yet another embodiment of a heat exchanger,
• 9 a three-dimensional representation of another embodiment of a hot water station,
• 10 a three-dimensional representation of a base area of the hot water station,
• 11 a schematic representation of a head area of the hot water station,
• 12 a three-dimensional representation of the head area of the hot water station, and
• 13 a cross-sectional view of the hot water station.

In the figures, identical or functionally equivalent components are provided with the same reference symbols.

1 shows schematically 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 extraction 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 extraction. A typical temperature of the hot water in the hot water tank 3 is 52 degrees Celsius. The heating takes place, for example, by a heat exchanger of a heat pump or a gas boiler, but is not limited to these means of heating.

Between the drinking water heater 1 and the extraction stations 71, 72, 73, 74, a circulation-free pipe system 9 is provided, which is designed so that hot water flows from the hot water tank 3 of the drinking water heater 1 to the extraction stations 71, 72, 73, 74. The hot water can be extracted at the extraction stations 71, 72, 73, 74 and flow out of the hot water system. Extraction stations 71, 72, 73, 74 can be used, for example, as a shower or Water tap. Two of the extraction stations 71, 72 and 73, 74 are each coupled to one of the hot water stations 51, 52, so that the water from the drinking water heater 1 flows to the extraction stations 71, 72 and 73, 74 through the first and second hot water stations 51, 52, respectively.

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 provided on the hot water stations 51, 52 for distribution lines 13 to extraction stations 71, 72, 73, 74. Several extraction stations are advantageous, as in 1 shown, installed in a row so that the distribution line 13 to the most distant extraction station 72, 74 is looped through further extraction stations 71, 73. The line volume in the pipes of each line route from the drinking water heater 1 to one of the extraction stations 71, 72, 73, 74 is less than or equal to a predetermined maximum line volume. This embodiment of a hot water system is a small system within the meaning of the German Drinking Water Ordinance, in 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 obligatory annual microbiological drinking water test is not necessary.

The hot water system with two hot water stations 51, 52 can, for example, be intended for two small apartments, each of which has a hot water station 51, 52. For a two-person apartment, one hot water station is sufficient for the outlets in the kitchen and bathroom. Alternatively, the hot water system can be intended for a larger apartment for three to four people. One hot water station 51, 52 is then intended for the bathroom and kitchen and their outlets.

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

In this 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 line volume in the pipes of the line path is less than or equal to the specified maximum line volume of 3 liters. Cold water is fed separately via pipes 19 for cold water and separately from the hot water system to the extraction stations 71, 72, 73, 74.

Warm drinking water from the drinking water heater 1, which flows into the supply lines 11 and distribution lines 13 when it is drawn off, but is no longer drawn off, cools down. The next time it is drawn off, this cooled water must first flow away until warm water from the drinking water heater 1 is again available at the drawing stations 71, 72, 73, 74. The warm water stations 51, 52 shorten the time until warm water is available at the drawing stations by storing warm water and, advantageously, can also heat cold water.

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

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 achieve further To bridge line paths 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.

The hot water station 51 comprises a water tank 60 which is 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 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, so that the hot water system is a small system in accordance with the German Drinking Water Ordinance.

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

The water tank 60 is designed to heat the water electrically. If there is cold water in the water tank 60, either 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 tank 60, even if no water has been drawn off for a long time. In one embodiment, heating to 60 degrees Celsius is provided after a long period of inactivity. Heating can take place, 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 tank 60 has risen above another predetermined threshold. This process can be repeated if the water temperature drops again. For heating, a heating element 66 is provided as a heating device, which can have an exemplary power consumption of 100 watts. This value is significantly lower than the power consumption of a continuous flow heater for heating water in a station.

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 part 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 conversion enthalpy, whereby sublimation and melting enthalpy are relevant in this embodiment. The phase change can take place 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 takes place just below or in the range of the desired delivery temperature range for the hot water delivered. 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 provided at the draw-off stations 71, 72, 73, 74. If no water is drawn off for a long 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 down, and the thermal energy released is transferred to the stored or flowing water and heats it up.

For example, water at a temperature of approximately 50 degrees Celsius from the supply line 11 can cause the phase transition of the phase change material that liquefies in this temperature range. Nevertheless, water at a temperature of approximately 40 degrees Celsius can still be withdrawn at the withdrawal stations 71, 72, 73, 74 despite the phase change.

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 extraction stations 71, 72, 73, 74. Compared to a continuous flow heater in a station, the energy required 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 extracted without reheating. The hot water station 50 can provide hot water at the extraction stations 71, 72, 73, 74 after just 8 to 15 seconds. In addition, the lower pressure loss of a plate heat exchanger enables Heat exchanger 64 a discharge capacity of 15 liters/min.

The hot water station 51 with water tank 60 has exemplary dimensions of 540 × 300 × 82 mm. It weighs approximately 9 kg. ½'' IG connections are provided. Internal stainless steel piping with a ¼'' IG connection is provided for on-site installation of the transfer point. The piping is available in one example as a raw or finished set. Alternatively, it can already be installed on the hot water station 51 when it is delivered.

The hot water station 51 significantly shortens the time until hot water is available at the extraction stations. Even shorter times until it is available are possible by providing optional small storage stations 80 at the extraction stations 71, 72, 73, 74.

1 shows that the extraction stations 71, 72, 73, 74 in this embodiment of the hot water system each have a small storage station 80 in which hot water can be stored in the immediate vicinity of the outlet from the extraction stations 71, 72, 73, 74. The small 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 installed unobtrusively under a washbasin or in a washbasin base cabinet. The small storage station 80 can typically store a maximum of 0.5 liters of water. The optional small storage station 80 increases convenience in terms of the hot water supply time. It is reduced to less than 8 seconds. 5 seconds is a typical value.

The mini storage station 80 is similar to the one used in connection with 2 described hot water station 51 and has a small water reservoir and advantageously also the other features described above, i.e. thermal insulation and heating device, in order to provide hot water.

The small storage station 80 includes thermal insulation to slow down the cooling of the water. Advantageously, the small storage station 80 also includes a heating device, for example with a heating element, and a heat exchanger with phase change material, the mode of operation of which has been described above. The electrical power consumption of the small storage station 80 is in the range of 50 watts.

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 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 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 for the system to be a small system.

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

The hot water stations 51, 52 with water storage 60 and the mini storage stations 80 have very low electrical energy consumption, especially in comparison 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 60 can be almost neglected in comparison to the power consumption of stations with an instantaneous water heater. This advantage is particularly evident in large systems with many hot water stations 51, 52 and thus also many residential units. The low energy consumption with an exemplary power consumption of 50 to 100 watts results in a significantly smaller total network connection power compared to a conventional system or a system with instantaneous water heaters in the stations. With several hot water stations 51, 52, a simultaneity lock to limit the number of hot water stations 51, 52 operating simultaneously is no longer necessary. Smaller cable cross-sections can be used for the power supply. Additional transformer stations are not required. This overall lower cost of power supply also leads to less planning effort for the system and in particular the electrical supply.

3 shows schematically 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 small storage station 80. Between the plates, phase change material of the secondary circuit 200 and water of the primary circuit 100 are alternately provided. Warm water with a temperature above the melting point of the phase change material releases thermal energy to the secondary circuit 200 with solid phase change material so that the phase change material melts and latent heat from the warm water is stored in the melted phase change material. When cold water with a temperature below the melting point is in the primary circuit 100, thermal energy that has been stored as latent heat in the phase change material is released to the cold water in the primary circuit 100 when the phase change material solidifies and heats it.

4 shows a schematic section of a heat exchanger 64, which has, for example, finned tubes 92 through which the water of the primary circuit 100 flows. Outside the finned tubes 92, phase change material is provided in the secondary circuit 200. The finned tube 92 is a tubular component that has fins 94 on its outside to increase the tube surface. This improves the transfer of thermal energy between the inside and outside of the tube. The finned tubes 92, in particular the fins 94, are advantageously made of material that conducts heat well.

The design of the heat exchanger 64 is not limited to the embodiments mentioned. Good heat transfer, a large surface area over which the thermal energy is transferred, but also weight, given the preferred wall mounting, are points that play a role in the design. Another embodiment of the heat exchanger 64 comprises aluminum bodies with a large surface area.

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

In this embodiment, two hot water branches 10, 20 are provided, through which, on the one hand, hot water from the drinking water heater 1 is conducted 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 conducted to a third and fourth extraction 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 installation and small storage stations 80 as in the previous embodiment.

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.

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.

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

As in the previous embodiment, the hot water station 50 comprises a water 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 intended 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. If there are more than two primary circuits, fittings for the inlet and outlet would also be provided several times, 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.

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. Inflowing and outflowing water 111, 131 of the first hot water branch 10 flows through the first water inlet 55 or outlet 57, respectively, and inflowing and outflowing water 112, 132 of the second hot water branch 20 flows through the second water inlet 55 or 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, which run between the drinking water heater 1 and the hot water station 50.

The secondary circuit of the heat exchanger 64 comprises phase change material and interacts with both primary circuits so that thermal coupling occurs through the secondary circuit, as heat from each of the primary circuits can be stored in the secondary circuit and transferred 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 to be released to the other primary circuit.

7 shows a schematic section of the heat exchanger 64, which is designed as a plate heat exchanger by way of example. Between the plates, 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 alternately provided. However, the water of the first primary circuit 100 flows spatially separated from the water of the second primary circuit 102 through the plates, preferably on 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 the second primary circuit 100, 102, even if the storage of the thermal energy was only caused by the extraction in one of the primary circuits 100, 102. Nevertheless, both primary circuits 100, 102 can charge the phase change material.

For example, a shower, in which a lot of hot water is typically drawn off over a longer period of time in 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 extraction 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.

8th shows schematically a section of an embodiment of a heat exchanger 64, which has finned tubes 92 through which the water of the primary circuits 100, 102 flows. There are first and second finned tubes through which water of the first and second primary circuits 100, 102 flows, respectively, without a liquid exchange taking place. The tubes 92 are advantageously arranged alternately, so that a first tube is adjacent to second tubes and vice versa.

The other features of the hot water station and its use, namely the thermal insulation and the heating of the stored water, which were previously related to the 1 to 4 have been described, are also available for the hot water station 50 in the 5 to 8 provided to heat the water in the hot water station 50 for both hot water branches 10, 20 and to slow down its cooling. The thermal insulation 62 can thus keep the hot water warm enough for use for up to 24 hours. In this embodiment, a 100-watt heating element 66 is also provided, with which the cooled water in the water tank 60 can be heated to 60 degrees Celsius after a longer period of inactivity.

This in connection with the 5 to 8 The embodiment of the hot water station 50 described has the same advantages as that described in connection with the 1 to 4 described embodiment of the hot water station 51, 52. 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 extraction stations 71, 72, 73, 74 is higher in the hot water station 50 at more than 20 liters/min due to the extraction stations 71, 72, 73, 74 being supplied 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.

9 shows a further embodiment of a hot water station 50. The hot water station 50 has an elongated basic shape with two columns and front fastening areas 96, which are designed as foot-shaped extensions with a flat contact surface. Fasteners, for example screws, can be guided through holes 97 in the fastening areas 96 in order to fasten the hot water station 50 to a wall, for example.

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 electrics and cables that connect electrical components on both end faces run in a protective tube 99 arranged longitudinally next to the main module 98.

The hot water station 50 has a length of more than one meter, typically a length in the range of 1.5 meters.

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 extraction 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 be designed, for example, as a 50W heater with a heating rod. The heating device is used when there is little tapping 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.

Despite the designations head and base area 82, 81, the orientation of the mounted hot water station 50 is not limited to the 9 shown vertical orientation. The hot water station 50 can also be mounted upside down, lying flat or at an angle, preferably flush-mounted.

10 shows the base area 81 of the hot water station 50 with water inlet and water outlet of the hot water station 50, so that water inflow and outflow occur at the same front side, which simplifies installation. The water from the drinking water heater enters at the water inlet 55 and the water 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 and is diverted there 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 provided for the extraction stations 70, 71, 72, 73, 74.

11 shows schematically 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 into the outer water chamber 151, 152. The height of the bypass chamber 84 is in the range of 10 mm.

12 shows the head region 82 of the main module 98 with filling openings 85 in the flow 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 occur through annular gaps 86.

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 a 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 of the chambers 201, 202 and have a cross-section with radial webs that can be branched in a forked manner. An external chamber is a vacuum chamber 270 for thermal isolation, 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 rod, which in one embodiment is approximately 200 mm long and is positioned in the head region 82 or adjacent to the head region 82.

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 leaves the hot water station 50 it has a temperature of approximately 45 degrees Celsius. After the cooled water has passed through the device and has 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 out of the hot water tank 3 and recharges the phase change material 250 by causing a phase change. If no hot water is drawn off for a long period of time, the phase change material 250 can be kept at temperature with little energy expenditure so that it does not solidify.

The features specified above and in the claims as well as those shown in the figures 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.

Reference symbols

1

Drinking water heater

3

Hot water tank

9

Pipeline system

11

supply line

10, 20

Hot water branch

13

Distribution line

19

Cold water pipe

21

House connection

31

Pressure regulator

50, 51, 52

Hot water station

55

Water inlet

57

Water outlet

60

water-tank

62

Thermal insulation

64

Heat exchanger

66

Heating element

70, 71, 72, 73, 74

Removal station

80

Micro storage station

81

Base area

82

Head area

84

Circulation chamber

85

Filling opening

86

gap

92

Finned tube

94

rib

96

Mounting area

97

Hole

98

Main module

99

Protective tube

100, 102

Primary circuit

111, 112

incoming water

131, 132

draining water

151, 152

Water chamber

200

Secondary circuit

201,202

chamber

250

Phase change material

260

structure

270

Vacuum chamber

Claims (15)

Hot water station (50, 51, 52) for providing hot drinking water with 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) which is coupled between the water inlet (55) and the water outlet (57) and is designed to store water, wherein the water reservoir (60) comprises a heat exchanger (64) with a primary circuit (100) which is designed for the water to flow through it, and a secondary circuit (200) with phase change material which is designed to store thermal energy as latent heat from the water in the primary circuit (100) and to release thermal energy which has been stored as latent heat to the water in the primary circuit (100). Hot water station (50, 51, 52) after Claim 1 , wherein a melting temperature of the phase change material is above a predetermined minimum release temperature of released warm water. Hot water station (50, 51, 52) after Claim 1 or 2 , with a predetermined delivery temperature range of delivered warm water between 45 and 60 degrees Celsius. Hot water station (50, 51, 52) after Claim 2 or 3 , whereby the melting temperature of the phase change material is between 40 and 50 degrees Celsius, in particular between 42 and 48 degrees Celsius. Hot water station (50, 51, 52) according to one of the preceding claims, which is designed to heat the stored water electrically. 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. Hot water station (50, 51, 52) after 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. Hot water station (50, 51, 52) according to one of the preceding claims, wherein the water spout cher (60) comprises a thermal insulation (62) which slows down the cooling of stored warm water. Hot water station (50, 51, 52) after Claim 8 , wherein the thermal insulation (62) comprises insulating material arranged outside the water reservoir (60). 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). Hot water station (50, 51, 52) after 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. Hot water station (50, 51, 52) after 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 which has been stored as latent heat into water in the first and/or second primary circuit (100, 102). 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. 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. 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.

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