Hot water system

Abstract

A hot water system having: a drinking water heater (1) having a hot water reservoir (3); -an outlet station (70, 71, 72, 73, 74); -a circulation-line-free line system (9) between the drinking water heater (1) and the outlet station (70, 71, 72, 73, 74), designed such that heated drinking water flows from the drinking water heater (1) to the outlet station (70, 71, 72, 73, 74) along a line path in the line system (9), in which the pressure in the line system and the line cross-section of the line system depend on the length of the line path, the pipeline path is arranged in the pipeline system (9) such that the pipeline volume of the pipeline path is less than or equal to a predefined maximum pipeline volume, and wherein the pipeline path comprises a first part and a second part, and the hot water station (50, 51, 52) is arranged in the pipeline system (9) and between the first part and the second part, and is designed to heat and / or store drinking water.

Description

Technical Field

[0001] The present invention relates to a hot water system. Background Art

[0002] A hot water system includes a potable water heater having a hot water storage tank and one or more water outlets, and hot water flows from the potable water heater through a pipeline system to the one or more water outlets.

[0003] A long pipeline path means that it takes a long time to supply hot water from the potable water heater to the water outlet. If there is no water outlet, the water stays in the pipeline system and cools. If water bacteria such as Legionella multiply rapidly, the water that has stayed in the pipeline system for a long period of time may cause hygiene problems.

[0004] In a conventional pipeline system with a long pipeline path, for convenience, a circulation pipeline is provided, which ensures that hot water circulates in the pipeline system and thus always flows through or near the water outlet, so that hot water is available immediately or after a short time at the water outlet. If the temperature of the circulating hot water is high enough, it will kill water bacteria, thereby reducing hygiene problems. However, circulation requires a pump, which consumes as much energy as heating the circulating hot water. Heating the continuously circulating potable water to about 60 degrees Celsius (where there may be only a short water outlet time during which water is drawn) is complex and involves heat loss and power consumption. In addition, in a system with a heat pump for heating, the largest heat pump-related losses occur at about 60 degrees Celsius. Circulating the potable water also causes mixing of the potable water stored in the hot water storage tank, which has a negative effect on the performance of the heat pump. These effects result in a loss of about 50% of the energy used.

[0005] If the volume in the pipeline between the potable water heater and at least one water outlet is greater than 3 liters, then according to German law requirements, for hygienic reasons, a circulation pipeline or a temperature control band must be installed compulsorily.

[0006] According to the German Drinking Water Ordinance, a distinction is made between small and large systems. In a small system, the volume in the pipeline path between the potable water heater and the water outlet point is less than or equal to 3 liters. In addition, the capacity of the hot water storage tank of the potable water heater is less than or equal to 400 liters. Unless the hot water system is in a single-family or two-family house, if these requirements are not met, it is a large-scale system. For large systems in public or commercial buildings, including rental apartments, annual microbiological potable water testing must be carried out. This inspection obligation does not apply to small systems.

[0007] CH 100 898 A shows a hot water supply system, in which an adiabatic hot water storage tank is provided between the water heater and the water outlet.

[0008] DE 41 39 288 A1 shows a hot water supply, in which a continuous flow heater is arranged between a water heater and a water outlet station, and the continuous flow heater is used for disinfection and heating.

[0009] DE 10 2011 122 639 A1 shows a hot water supply, in which the continuous flow heater between the water heater and the water outlet station is controlled such that it reheats the water when water is drawn from a household appliance, rather than when water is drawn manually.

[0010] AT 374 269 B shows a hot water supply, in which a distributor is arranged between the water heater and the water outlet station. If the temperature drops below a minimum value, the water passes through a branch of the pipe through which the water is heated.

[0011] DE 10 2014 225 693 A1 shows a hot water supply, in which a distributor is arranged between the water heater and the water outlet station. If necessary, a parallel second pipeline with an additional heat source can provide additional hot water.

[0012] DE 295 03 746 U1 shows a hot water generator for storing latent heat. SUMMARY OF THE INVENTION

[0013] The object of the present invention is to provide an improved hot water system.

[0014] This object is achieved by a hot water system having the features of claim 1.

[0015] The hot water system is provided with: a drinking water heater having a hot water storage tank; a water outlet station; a non-circulating pipeline system between the drinking water heater and the water outlet station, and the non-circulating pipeline system is designed such that the heated drinking water flows from the drinking water heater along a pipeline path in the pipeline system to the water outlet station. The pressure in the pipeline system and the cross-sectional area of the pipeline of the pipeline system depend on the length of the pipeline path, such that the pipeline volume of the pipeline path is less than or equal to a given maximum pipeline volume. The pipeline path includes a first part and a second part, and a hot water station is arranged between the first part and the second part, and the hot water station is designed to heat and / or store drinking water.

[0016] A memory for drinking water specially arranged for heating, whether from the drinking water heater or heated by the hot water station.

[0017] The hot water system has no circulation pipelines; this means there are no circulation pipelines in which hot water continuously circulates. This saves energy. In a system with a heat pump, due to the lack of circulation, compared with a system with circulation pipelines, approximately 50% of the energy is saved because the energy consumption for heating and circulating the drinking water is eliminated. In addition, due to the lack of mixing in the hot water storage tank, the heat pump can operate more efficiently. Advantageously, in a pipeline system for instant water heating using the heat from a water-based central heating system, there is no fresh water station, so the energy consumption is lower compared with a conventional hot water system.

[0018] The drinking water heater heats the drinking water set on the inlet side and stores the heated drinking water as hot water in the hot water storage tank. The temperature of the hot water is usually in the range of 45 to 60 degrees Celsius, especially 50 to 60 degrees Celsius, and can be drawn at the faucet. Multiple water outlet stations can be set in the hot water system. Examples of the water outlet points are faucets and sprinklers.

[0019] The pipeline volume of the pipeline path is the volume of the pipelines in the pipeline system through which water flows from the drinking water heater to the water outlet station.

[0020] The size of the pressure and the pipeline cross-section, especially the inner pipeline diameter, depends on the length of the pipeline path between the drinking water heater and the water outlet station and the specified maximum pipeline volume. For hygienic reasons, the maximum pipeline volume is low. Advantageously, the maximum pipeline volume complies with legal or structural specifications. A small system within the meaning of the German Drinking Water Ordinance (especially DVGW worksheet W551) has a maximum pipeline volume of 3 liters, so such a system does not require mandatory annual microbiological drinking water testing.

[0021] Compared with a conventional hot water system in which the pipeline length of a pipeline with a given pipeline cross-section is limited by a given maximum pipeline volume, in the hot water system according to the present invention, both the pipeline cross-section and the pressure are adjusted to achieve the desired pipeline length regardless of the given maximum pipeline volume. When adjusting the pipeline cross-section, the inner pipeline diameter is adjusted. The greater the desired pipeline length, the higher the pressure and the smaller the pipeline cross-section (i.e., the inner pipeline diameter). A higher pressure also means a higher flow rate, so there are fewer deposits in the pipeline and bacterial growth is inhibited. The length of the pipeline path between the drinking water heater and the water outlet station is longer than that in a conventional hot water system without circulation pipelines. The length of the pipeline path is advantageously longer than 25 m, especially longer than 35 m, especially longer than 45 m, and especially longer than 65 m.

[0022] Between a first section and a second section, a hot water station is provided in the pipeline system and drinking water flows through said hot water station. The hot water station is designed to heat and / or store hot water provided on the inlet side. If previously heated drinking water has remained in the pipeline path for a long time without hot water being drawn off, the water that has cooled can be reheated by the hot water station before being drawn off. Additionally or alternatively, hot water can be temporarily stored in the hot water station and drawn off therefrom. This hot water may have flowed out of a hot water storage tank in the hot water station or may have been heated in the hot water station. The hot water heated by the hot water station can have the same temperature range as the hot water provided by the hot water storage tank; however, advantageously, the hot water station heats the water to a higher temperature, for example 60 degrees Celsius. The preheating and / or intermediate storage by the hot water station improves comfort because hot water is available more quickly at the outlet point compared to a situation where no hot water station is provided and cold water has to be discharged from the pipeline first. The hot water station is a hot water transfer point between the supply pipeline from the drinking water heater and a separate pipeline to the outlet point, which is formed by a distribution pipeline between the hot water station and the outlet point. The first section of the pipeline path is the supply pipeline. The second section is the distribution pipeline between the hot water station and the outlet point. The hot water station has a connection for the distribution pipeline and thus provides a hot water branch line. In small residential units, hot water branch lines are typically provided for the kitchen and the bathroom. In larger residential units, typically two hot water branch lines are provided, one for the kitchen and one for the bathroom.

[0023] The optimization of the pressure and the pipeline cross-section can be concentrated on one of the sections. When concentrated on the first section (i.e., the supply pipeline to the hot water station), the maximum pipeline volume is divided into a first maximum volume of the first section and a second maximum volume of the second section. The first pressure in the first section and the first pipeline cross-section of the first section depend on the length of the first section such that the pipeline volume of the first section is less than or equal to the first maximum volume. Then, it is also required that the pipeline volume of the second section is less than or equal to the second maximum volume. This requirement must also be met for the distribution pipeline of the second section.

[0024] Advantageously, the first pressure is different from the second pressure of the second section. To cover the long distance of the supply pipeline, hot water flows through the supply pipeline at a high pressure. This pressure is reduced in the hot water station. In one embodiment, a booster is installed upstream of the drinking water heater in order to achieve a high pressure in the first section. To reduce the pressure, a pressure regulator is provided in the hot water station or the pressure regulator is installed upstream of the hot water station.

[0025] In one embodiment, one or more additional water outlets are connected to the hot water station, wherein the pipeline volume in each pipeline path between the potable water heater and the additional water outlet or one of the additional water outlets is less than or equal to a specified maximum pipeline volume. Thus, for the pipeline route to each water outlet, the pipeline volume is less than or equal to the maximum pipeline volume. Generally, the pipeline path to the water outlet furthest from the potable water heater has the maximum pipeline volume, so generally speaking, when sizing, it suffices to make this pipeline volume less than or equal to the maximum pipeline volume. Between the furthest water outlet and the potable water heater, additional water outlets may be provided, which are advantageously connected to each other by a loop-through device.

[0026] The following are examples of the inner pipe diameter and pressure for a specified maximum pipeline length. For example, in a hot water system, the inner pipe diameter can be less than or equal to 11.6 mm. Advantageously, the pressure is then greater than or equal to 0.71 bar. This allows a pipeline length of 25 m to the hot water station to be achieved. For example, the inner pipe diameter can be less than or equal to 9.6 mm. Advantageously, the pressure is then greater than or equal to 2.47 bar. This allows a pipeline length of 35 m to the hot water station to be achieved. For example, the inner pipe diameter can be less than or equal to 8.4 mm. Advantageously, the pressure is then greater than or equal to 6.01 bar. This allows a pipeline length of 45 m to the hot water station to be achieved. For example, the inner pipe diameter can be less than or equal to 7 mm. Advantageously, the pressure is then greater than or equal to 20.81 bar. This allows a pipeline length of 65 m to the hot water station to be achieved. This maximum pipeline length significantly exceeds the pipeline path in a conventional hot water system without a circulation pipeline. In the above examples, the pipe can have an outer diameter of 16 mm, thus facilitating assembly and installation by ensuring uniform outer pipe dimensions.

[0027] In one embodiment, the hot water station includes a continuous flow heater that is designed to heat water during the discharge time until hot water from the potable water heater has reached the hot water station. This increases comfort in the long supply pipeline because hot water is immediately available at the water outlet point even if the water in the pipeline is cold when drawn.

[0028] In one embodiment, the hot water station includes a bypass valve that bridges the instantaneous water heater once hot water with a specified temperature is available on the inlet side of the hot water station. Hot water with a specified minimum temperature bypasses the instantaneous water heater. However, the hot water station can also be provided with an additional heater that additionally heats the hot water from the potable water heater.

[0029] In one embodiment, the hot water station includes a small hot water storage tank, the storage capacity of which is lower than that of the hot water storage tank of the potable water heater. In this embodiment, the hot water station acts as a decentralized buffer, thereby providing hot water closer to the water outlet station and thus reducing the time until hot water is available at the water outlet station.

[0030] Advantageously, the small hot water storage tank has thermal insulation, for example made of a heat-insulating material, so as to reduce heat loss to the environment and delay the cooling of the hot potable water. Additionally or alternatively, the small hot water storage tank is designed to heat the water stored therein. This enables reheating of the cooled water during a longer downtime period in which no water is drawn from the small hot water storage tank and hot water has flowed in from the potable water heater. Alternatively, when the stored water cools below a predefined threshold, the stored water can be heated to counteract the cooling so that hot water is always available in the small hot water storage tank. Heating at a predefined time, for example in the morning, ensures that hot water is available when it is usually needed.

[0031] Additionally or alternatively, the small hot water storage tank has a heat exchanger. The heat exchanger contains a phase change material, abbreviated as "PCM". Potable water flows in a primary circuit of the heat exchanger. The secondary circuit contains the phase change material, which stores most of the thermal energy supplied to the phase change material from the primary circuit in the form of latent heat (for example during the phase change from solid to liquid). The flowing and / or stored hot water that may have been heated in the hot water station causes a phase change of the phase change material, such that the phase change material stores a part of the thermal energy of the hot water. However, there is sufficient hot water available at the water outlet station, especially when hot water is flowing through. The phase change material can be, for example, waxy and liquefies when heat is applied. If there is no water outlet for a long time, the latent heat stored in the phase change material is used to heat the cooled water to counteract the cooling. The phase change material solidifies again and releases the thermal energy released during this period into the stored water. Electric heating can support the supply of hot water by reheating the stored water (possibly also multiple times) when the stored water cools below a predefined threshold in order to counteract the cooling so that hot water is always available in the small water storage tank. The energy required for this purpose is significantly lower than the case where no phase change material is provided.

[0032] In one embodiment, the heat exchanger of the small hot water storage has: two separate potable water primary circuits; and a secondary circuit including a phase change material. This design of the hot water station combines the functions of two hot water stations, as it provides potable water for two hot water branches, for example, potable water for the bathroom and kitchen of an apartment. The pipelines of the two branches are separate from each other. There is no water exchange. However, the thermal coupling occurs through the secondary circuit, because the thermal energy from each of the primary circuits can be stored in the phase change material and released from the phase change material to each primary circuit. In other words, there is a heat exchange between each of the two separate primary circuits and the secondary circuit, while there is no water exchange between the two primary circuits. More than two primary circuits can also be provided and thermally coupled in this way.

[0033] For example, a long shower using the hot water from the outlet of one hot water branch can cause thermal energy to be stored, and then the stored thermal energy is released for the water in another hot water branch from the outlet in the kitchen. This design provides 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 the stored energy of this charging can also be used for another primary circuit.

[0034] If enough hot water has been stored, the water storage can also be bypassed through a bypass valve. However, the normal flow of hot water also advantageously causes the normal charging of the phase change material acting as a memory.

[0035] In one version, the potable water heater is connected to a heat pump, such that the heat pump heats the potable cold water into hot water. The non-circulating pipeline system results in high efficiency of the hot water system, because the efficiency of the heat pump depends on the temperature gradient. This is significantly higher between the hot water in the hot water storage and the incoming cold water compared to a conventional system with circulating pipelines. Since no circulating pipelines are provided, the turbulence caused by the returning hot water and the resulting reduction of the temperature gradient are avoided. Description of the Drawings

[0036] Some exemplary embodiments are explained in more detail below with reference to the drawings. In the drawings:

[0037] Figure 1 An exemplary embodiment of the hot water system is schematically shown,

[0038] Figure 2 Another exemplary embodiment of the hot water system is schematically shown,

[0039] Figure 3 Yet another exemplary embodiment of the hot water system is schematically shown,

[0040] Figure 4 Yet another exemplary embodiment of the hot water system is schematically shown,

[0041] Figure 5 shows schematic details of an exemplary embodiment of a hot water system, and

[0042] Figure 6 schematically shows further details of an exemplary embodiment of a hot water system.

[0043] In the figures, identical or functionally equivalent components have the same reference numerals. Detailed Description

[0044] Figure 1 Schematically shows an exemplary embodiment of a hot water system having a drinking water heater 1, which has a hot water storage tank 3 and, by way of example, two hot water stations 51, 52 and three outlet stations 71, 72, 73. The drinking water heater 1 heats cold drinking water flowing into the hot water storage tank 3 via the house connection 21 and stores it in the hot water storage tank 3 for outlet. Heating is effected, for example, by means of a heat exchanger 15.

[0045] Between the drinking water heater 1 and the outlet stations 71, 72, 73, a pipeline system 9 without a circulation line is provided, which is designed such that hot water flows from the hot water storage tank 3 of the drinking water heater 1 to the outlet stations 71, 72, 73. The hot water can be drawn off at the outlet stations 71, 72, 73, which can be, for example, sprinklers or faucets. The hot water stations 51 and 52 are hot water transfer points and are connected to the drinking water heater 1 via supply lines 11. Distribution lines 13 lead from the hot water stations 51, 52 to the outlet points 71, 72, 73, 74. A number of connections for the distribution lines 13 to the outlet stations 71, 72, 73 can be provided at the hot water stations 51, 52. A number of outlet stations can advantageously be installed in series such that the distribution line to the most distant outlet station passes through the other outlet stations in a loop.

[0046] Between the drinking water heater 1 and the first outlet station 71, the hot water flows along a pipeline path via the first hot water station 51. The pipeline path has a first part between the drinking water heater 1 and the first hot water station 51 and a second part between the first hot water station 51 and the first outlet station 71. The pipeline volume in the pipes of the pipeline path is less than or equal to a predefined maximum pipeline volume of 3 liters.

[0047] Between the potable water heater 1 and the second water outlet station 72 and the third water outlet station 73, the hot water flows via the second hot water station 52. The pipeline path between the potable water heater 1 and the second water outlet station 52 has a first part between the potable water heater 1 and the second hot water station 52 and a second part between the second hot water station 52 and the second water outlet station 72. The pipeline volume in the pipeline path is less than the specified maximum pipeline volume of 3 liters. The pipeline path between the potable water heater 1 and the third water outlet station 73 extends via the second hot water station 52 and the second water outlet station 72, where the pipeline circulates. The pipeline path has a first part between the potable water heater 1 and the second hot water station 52 and a second part between the second hot water station 52 and the third water outlet station 73. The pipeline volume in the pipeline of the pipeline path is less than the specified maximum pipeline volume. This pipeline path leads to the farthest water outlet station 73 and extends beyond the previously described pipeline path to the second water outlet station 72. It has the largest pipeline volume among all three pipeline paths. The pipeline volume in each pipeline path is less than the specified maximum pipeline volume of 3 liters.

[0048] The hot water system is a small system, where the pipeline volume of each pipeline path is less than 3 liters. In addition, the volume of the water storage tank 3 is less than or equal to 400 liters.

[0049] Such a hot water system with two hot water stations 51, 52 can be provided, for example, for two small apartments, in each of which the hot water stations 51, 52 are arranged. For a two-person apartment, one hot water station is sufficient for the water outlet points in the kitchen and the bathroom. Alternatively, the hot water system can be designed for larger apartments with three to four people. Then one hot water station 51 and 52 is provided for each bathroom and kitchen and their water outlet points. In the case of a hot water system for multiple residential units, such as in a multi-unit residential building or apartment complex, more than two hot water stations 51, 52 are provided. However, the hot water system is a small system.

[0050] The hot water system can be designed for very long pipeline paths. Depending on the desired length of the longest pipeline path, the pressure in the pipeline system and the pipeline cross-section (i.e., the inner pipeline diameter) of the pipeline system are selected such that the pipeline volume of each pipeline path is below the specified maximum pipeline volume. The longer the desired pipeline path length, the higher the pressure and the smaller the pipeline cross-section. The pipeline volume in each pipeline path is less than the maximum pipeline volume of 3 liters. The first part to the hot water station is advantageously optimized by allocating a part of the maximum pipeline volume to the first part. The remaining part of the maximum pipeline volume can be used for the second part. For example, 0.6 liters can be provided for the pipeline volume of the second part of the pipeline path after the heating station, and 2.4 liters can be provided respectively for the pipeline volume between the potable water heater 1 and the first hot water station 51 and the second hot water station 52. In another embodiment, 0.5 liters is provided for the second part and 2.5 liters for the first part.

[0051] The hot water system does not include a circulation pipeline or a fresh water station. This results in high economic efficiency in terms of investment and operation. The pipeline path can be very long, such that for example a large building can be supplied or a drinking water heater 1 can be operated outside the house.

[0052] Figure 2 Another exemplary embodiment of a hot water system with a drinking water heater 1 is schematically shown, which drinking water heater 1 has a hot water storage tank 3 as well as a hot water station 50 and a water outlet station 70.

[0053] Inside the house, a house connection 21 is provided, at which drinking cold water is provided and supplied to the drinking water heater 1. The house connection 21 includes a shut-off valve, a water meter, a non-return valve with a backflow prevention device and a filter. Starting from the house connection 21, the drinking water heater 1 is supplied with potable cold water at approximately 4 bar via a booster 23. The drinking water heater 1 includes a hot water storage tank 3 into which potable cold water flows, and which hot water storage tank 3 is designed to heat the potable cold water by means of a heat exchanger 15 and provide it as potable hot water in the hot water storage tank 3. The drinking water heater 1 provides hot water at an increased pressure (for example 9 bar) at the drinking water outlet. Generally, the hot water in the hot water storage tank 3 has a temperature at which water bacteria can no longer multiply, for example 50 degrees Celsius. The drinking water heater 1 is connected to a heat pump 49, which is designed to heat the water in the drinking water heater 1.

[0054] The hot water can flow to the hot water station 50 via a pipeline system 9 that has no circulation pipeline path and has a supply pipeline path 11 connected to the hot water station 50. The hot water that is not drawn off and remains in the pipeline system 9 for a longer period of time cools down. The hot water station 50 includes a pressure regulator 31 and an electric instantaneous water heater 33, which pressure regulator 31 is specifically designed for pressure reduction. One or more water outlet stations 70 can be connected to the hot water station 50 via a distribution pipeline 13. In this embodiment, a water outlet point 70 is provided, which is connected to the hot water station 50 via a distribution pipeline 13.

[0055] The instantaneous water heater 33 in the hot water station 50 is designed to heat the cooling water flowing out of the pipeline system during the discharge time until hot water has flowed from the drinking water heater 1 to the hot water station 50. Once hot water is available at the instantaneous water heater 33, the hot water bypass valve 17 bridges the instantaneous water heater 33.

[0056] Since the pipeline system 9 does not include a circulation pipeline path, when cold water has flowed out of the pipeline system 9, hot water from the hot water storage tank 3 is only available at the water outlet station 70 after the discharge time. At the same time, hot water is provided by the instantaneous water heater 33, which heats the water flowing out of the supply pipeline 11 until the pipeline delivers hot water. The instantaneous water heater is then turned off and bypassed by the bypass valve 17. The fully electronic instantaneous water heater 33 with the hot bypass valve 17 allows the instantaneous water heater to be continuously bypassed from a water temperature of 45 degrees Celsius.

[0057] In an exemplary embodiment having a short supply pipeline 11 to the drinking water heater 1 and thus a short discharge time, the hot water station 50 can be deactivated, for example, via an App.

[0058] Even in an emergency, that is, if the hot water storage tank only provides cold water and the auxiliary heating does not work, due to the presence of the instantaneous water heater 33, the user can still take a hot shower or draw hot water at a slightly reduced flow rate.

[0059] The hot water station 50 forms a hot water transfer point for a separate pipeline from the supply pipeline 11 to the water outlet station 70. For on-site installation of the transfer point, an internal stainless steel pipeline with a ¼'' IG connection is provided. In one embodiment, the pipeline can be used as an original or finished kit. Alternatively, it can already be installed in the hot water station 50 upon delivery.

[0060] In an exemplary embodiment, such a hot water station is a device with a rectangular basic shape, which can have exemplary dimensions of 540x300x82 mm. Its weight is approximately 9 kg, so it can be easily installed on the wall. A ½'' IG connection is provided. The typical discharge rate is 10 liters per minute (l / min). A connection power of 9 kW is provided for the instantaneous water heater. The maximum current consumption is 3x13 A, where the electrical connection is 400 / 16 / 3 V / A.

[0061] In one embodiment, the operating temperature of the hot water station 50 is 50 degrees Celsius or 55 degrees Celsius, so that the scale deposits are reduced. The operating pressure of the hot water station 50 is permanently 6 bar, where the pressure fluctuation can be up to 10 bar. The hot water station 50 is also advantageously designed to electrically reheat the supplied water, so that the hot water with a temperature of 50 degrees Celsius from the drinking water heater 1 is reheated to 60 degrees Celsius in the hot water station. This increases comfort.

[0062] All water-bearing components of the hot water system are made of drinking water quality, such as copper according to DIN 50930-6, brass according to EN CW617N, or stainless steel AISI 304.

[0063] The hot water system is sized such that it is a small system according to DVGW worksheet W551. This means that the hot water system can be operated at economic temperatures without the need for inspection.

[0064] The maximum pipeline path length between the drinking water heater and the transfer point is 65 m, with a maximum pipeline volume of 2.4 liters in the first part of the flow path. This allows for a maximum pipeline volume of 0.6 liters in the second part of the pipeline from the hot water station, which is the transfer point of the pipeline path, to the outlet station, so as not to exceed the maximum pipeline volume of 3 liters. By optimizing the pressure and pipe diameter in the second part, an additional pipeline path length of approximately 9 m can be achieved.

[0065] The following lists the combinations of pipes and pressures for various pipeline path lengths between the drinking water heater and the hot water transfer point, which also do not exceed the maximum pipeline volume of 3 liters. A maximum pipeline volume of 2.4 liters is provided for the flow path through the supply pipeline between the drinking water heater and the hot water transfer point. The pipes for the pipeline system can be made, for example, of polyethylene with improved temperature resistance, abbreviated as PE-RT.

[0066] For a 7x4.5 mm pipe with an outer diameter of 16 mm (i.e., 7 mm inner diameter and 4.5 mm wall thickness), a maximum pipeline path length of 65 m can be achieved. The pressure is 20.81 bar, allowing for a flow rate of 10 l / min of unmixed hot water. This system requires a pressure regulator 31, and in order to achieve the pressure in the supply pipeline 11, a booster 23 is also required, as Figure 2 shown. For other sizes, these components are optional.

[0067] For an 8.4x3.8 mm pipe with an outer diameter of 16 mm, a maximum pipeline path length of 45 m can be achieved. The pressure is 6.01 bar, allowing for a flow rate of 10 l / min of unmixed hot water. This system requires a booster 23.

[0068] For a 9.6x3.2 mm pipe with an outer diameter of 16 mm, a maximum pipeline path length of 35 m can be achieved. The pressure is 2.47 bar, allowing for a flow rate of 10 l / min of unmixed hot water. For this system, a booster 23 is required at pressures below 6 bar.

[0069] For an 11.6x2.2 mm pipe with an outer diameter of 16 mm, a maximum pipeline path length of 25 m can be achieved. The pressure is 0.71 bar, allowing for a flow rate of 10 l / min of unmixed hot water.

[0070] Figure 3Another exemplary embodiment of a hot water system is schematically shown. It includes a drinking water heater 1 having a hot water storage tank 3, a hot water station 50, and two outlet stations 71, 72. The drinking water heater 1 heats the cold drinking water flowing into the hot water storage tank 3 via the house connection 21 and stores it in the hot water storage tank 3 for water outlet. Heating is performed, for example, by a heat exchanger 15. For example, the hot water in the hot water storage tank 3 has a temperature of 52 degrees Celsius. If water is not drawn for a long time, the temperature in the pipeline path can be in the range of 20 to 51 degrees Celsius due to cooling.

[0071] Between the drinking water heater 1 and the outlet stations 71, 72, a pipeline system 9 without a circulation pipeline is provided, and hot water flows from the hot water storage tank 3 to the outlet stations 71, 72 through this pipeline system 9. The hot water station 50, as a hot water transfer point, is connected to the drinking water heater 1 via a supply pipeline 11. A distribution pipeline 13 leads from the hot water station 50 to the outlet points 71, 72. The outlet points 71, 72 are installed in series such that the distribution pipeline 13 circulates through the first outlet station 71 to the farthest second outlet station 72. The drawn cold water pipeline path 19 is connected in a similar manner.

[0072] The requirements and exemplary dimensions already mentioned in the previous exemplary embodiment are applied to the sizing of the supply pipeline 11 and the distribution pipeline 13. The pipeline volume in the pipeline of the pipeline path is less than or equal to the specified maximum volume of 3 liters. The volume of the supply pipeline 11 is at most 2.5 liters. The volume of the supply pipeline 13 to the farthest outlet point 72 is at most 0.5 liters.

[0073] During the discharge time, hot water can have been drawn from the small hot water storage tank 60 until the hot water has flowed from the drinking water heater 1 to the hot water station 50. In this exemplary embodiment, a bypass valve can also be provided, which bridges the hot water storage tank once the hot water from the drinking water heater 1 is available at the hot water station 50. Alternatively, water passes through the hot water station 50 regardless of its temperature, such that normal water exchange occurs.

[0074] The hot water station 50 includes a small hot water storage tank 60 for storing water. The storage volume of the small hot water storage tank 60 is smaller than the storage volume of the hot water storage tank 3 in the drinking water heater 1. A typical value is 5 liters. The storage volume of the small water storage tank 60 is not counted as part of the pipeline volume, and the pipeline volume should be less than the maximum volume. However, the total volume of all water storage tanks in the system must be less than the maximum storage volume in order to be exempt from inspection requirements. According to the drinking water regulations, the maximum storage volume is less than 400 liters.

[0075] The small hot water storage unit 60 has a heat insulator 62, which greatly slows down the cooling of the stored hot water. The small hot water storage unit 60 is also designed to electrically heat water so that warm drinking water is available in the small hot water storage unit 60 even when no water is drawn for a long period of time. In an exemplary embodiment, heating up to 60 degrees Celsius is provided after a long downtime. For example, once the temperature of the stored water has dropped below a predefined threshold, heating can be carried out until the temperature in the small hot water storage unit 60 has risen above another predefined threshold. For heating, a heating element 66 is provided, which may have an exemplary power of 100 watts.

[0076] The small hot water storage unit 60 includes a heat exchanger 64, such as a plate heat exchanger, which has a primary circuit for drinking water and a secondary circuit with a phase change material (or simply referred to as PCM). Alternative exemplary embodiments of the heat exchanger include finned tubes or aluminum bodies with a large surface area. The phase change material stores most of the thermal energy supplied to it from the primary circuit in the form of latent heat (especially during the phase change from solid to liquid). The phase change can occur at approximately 45 degrees Celsius, i.e., when the waxy phase change material melts. The phase change occurs below the desired temperature of the hot water. The flowing and / or heated hot water causes a phase change in the phase change material and stores a part of the thermal energy of the hot water. However, even after the hot water has passed and a part of its thermal energy has been used for the phase change, sufficient hot water is provided at the water outlet stations. If there is no water outlet for a long time, the thermal energy stored in the phase change material is used to slow down the cooling of the stored water. The phase change material solidifies and the thermal energy released during this period is discharged into the stored water and heats it.

[0077] For example, hot water at about 50 degrees Celsius from the supply pipeline can cause a phase transition of the phase change material, which liquefies within this temperature range. However, water at approximately 40 degrees Celsius can still be drawn from the water outlet stations 71, 72.

[0078] The combination of the heat exchanger 64 with the phase change material, the heating element 66, and the heat insulator 62 significantly reduces the energy required to provide hot water near the water outlet stations 71, 72. Compared with an instantaneous water heater, the energy requirement of the hot water station 50 is reduced to approximately one-seventh. The heat insulator 62 can keep the water temperature for at least 24 hours, so that hot water can be discharged without reheating. The hot water station 50 can provide hot water at the water outlet stations 71, 72 after only 8 to 15 seconds. In addition, the lower pressure loss of the plate heat exchanger enables a discharge capacity of 15 l / min. This means that the discharge capacity and the hot water supply time are better than the previous example with an instantaneous water heater.

[0079] The hot water station 50 with the small hot water storage 60 is almost the same size as the hot water station 50 with the instantaneous water heater 33. However, due to the insulation 62, the depth is usually greater. The connections and fittings are the same.

[0080] In this exemplary embodiment of the system, the outlet stations 71, 72 each have a micro heat storage 80, where hot water can be stored in the immediate vicinity of the outflow from the outlet stations 71, 72. The small heat storage 80 is a compact small heat storage, which is designed as, for example, an under-counter heat store. It can typically store about 0.5 liters of water. The optional micro heat storage 80 increases the convenience of the hot water supply time. It is reduced to less than 8 seconds. A typical value is 5 seconds.

[0081] The micro heat storage 80 includes insulation to slow down the cooling of the water. Advantageously, a heating element and a heat exchanger with a phase change material are also provided in the micro heat storage 80, and their operation has been described above. The electrical power consumption is about 50 watts.

[0082] The storage volume of the micro heat storage 80 is not included in the pipeline volume, which must be less than the maximum volume considered to be a small system. However, the storage volume of the micro heat storage 80 is counted into the total volume of all the water storages in the system, and this total volume must be less than the maximum storage volume to avoid inspection.

[0083] Since the storage volumes of the small hot water storage and the micro heat storage are not part of the pipeline volume, they do not exceed the maximum pipeline volume in this exemplary embodiment either.

[0084] Compared with the conventional system, the highly efficient series-connected small hot water storage 60 in the hot water station 50, especially in combination with the optional micro heat storage 80, enables a significantly shorter time before hot water is available at the outlet station.

[0085] Compared with a hot water station, especially compared with a hot water station having an instantaneous water heater, a hot water station having a small hot water storage tank and a micro heat storage have very low power consumption. Compared with the power consumption of a hot water station 50 having an instantaneous water heater 33, the power consumption of an optional micro heat storage and a hot water station 50 having a small hot water storage tank 60 is almost negligible. This advantage is particularly important in a large system having many hot water stations 50 and thus also many residential units. Due to the low energy consumption, i.e., having an exemplary power consumption of 50 to 100 watts, compared with a conventional system but also compared with the previous exemplary embodiments, the total mains connection power is significantly lower. If there are multiple hot water stations 50, it is no longer necessary to lock them simultaneously to limit the number of hot water stations 50 operating simultaneously. A smaller cable cross-section can be used for the power supply. No additional substation is required. The overall lower cost of the power supply also results in less system planning expenditure, especially for the planning of the power supply.

[0086] Figure 4 Another exemplary embodiment of a hot water system is schematically shown. The following description focuses on the differences from Figure 3 the previous exemplary embodiments.

[0087] In this exemplary embodiment, two hot water branches 10, 20 are provided. Through the two hot water branches 10, 20, on the one hand, hot water from the potable water heater 1 is guided to a first outlet station 71 and a second outlet station 72 in the first hot water branch 10, and on the other hand, hot water from the potable water heater 1 is guided to a third outlet station 73 and a fourth outlet station 74 in the second water branch 20. Although the hot water branches 10, 20 are separate so that no water exchange occurs, they both pass through the same hot water station 50. They have separate supply pipelines 11 and separate distribution pipelines 13. The hot water branches 10, 20 are configured with a circulation device and a micro heat storage 80, as in the previous exemplary embodiments.

[0088] As in the previous exemplary embodiments, the hot water station 50 includes a small hot water storage tank 60, a heat insulator 62, a heat exchanger 64, and a heating element 66. Since the hot water station 50 is provided for two hot water branches 10, 20, the hot water station 50 has two connectors for their distribution pipelines 13. The housing size is also larger than that in the previous exemplary embodiments because it stores more water to supply the two branches 10, 20.

[0089] In each of the branches 10, 20, the pipeline volume in the pipeline of the pipeline path is less than or equal to a predefined maximum pipeline volume of 3 liters.

[0090] The two water branches 10, 20 pass through the same hot water station 50 as two primary circuits of the heat exchanger 64. Figure 5A hot water station 50 is schematically shown with influent and effluent water 111, 131 of a first branch 10 and influent and effluent water 112, 132 of a second branch 20. Drinking water is not mixed between the branches 10, 20. Mixing also does not occur in the hot water station 50. In addition to the separate distribution line 13, the hot water branches 10, 20 also have separate supply lines 11 extending between the drinking water heater 1 and the hot water station 50.

[0091] The secondary circuit of the heat exchanger 64 includes a phase change material and interacts with two primary circuits such that thermal coupling occurs through the secondary circuit, since heat from each of the primary circuits can be stored in the secondary circuit and discharged from the secondary circuit to each of the primary circuits. In this way, the phase change material can be charged by one primary circuit and then the stored thermal energy can be transferred to the other primary circuit.

[0092] Figure 6 Schematically shown for Figure 5 Details of an exemplary embodiment of the heat exchanger 64 of a previous exemplary embodiment for, which heat exchanger is designed as, for example, a plate heat exchanger. Between the plates, the phase change material 68 and the water of the first branch 10 and the second branch 20 are alternately arranged. However, the water flow in the first branch 10 of the primary circuit flows through plates spatially separated from the water in the second branch 20 of the secondary circuit, preferably in an alternating form, such that the water in the first branch 10 flows through the phase change material 68 between two adjacent plates flowing on one side, and the water in the second branch 20 flows through the material on the other side. As a result, even if the storage of thermal energy is caused only by the effluent water in one of the branches 10, 20, the thermal energy stored in the phase change material 68 can be transferred to both the first primary circuit and the second primary circuit. However, both primary circuits can charge the phase change material 68.

[0093] For example, a sprinkler in the first branch 10 (where typically a large amount of hot water is drawn over a long period of time) can cause thermal energy to be stored in the secondary circuit. This stored thermal energy can then be released for water extraction in the kitchen in the second branch 20 and also, for example, for handwashing in a bathroom connected to the first branch 10.

[0094] Other features of the hot water station and its use, namely, the insulation and heating of the stored water previously described in connection with Figure 3 are also provided in the Figures 4 to 6 hot water station in order to heat the water in the hot water station for both branches 10, 20 and slow down its cooling. In this way, the insulation 61 can keep the hot water hot enough for effluent water for up to 24 hours. In this exemplary embodiment, a heating element 66 of 100 watts is also provided, which can heat the cooling water in the small hot water reservoir 60 to 60 degrees Celsius after a long downtime.

[0095] Combined Figures 4 to 6 The exemplary embodiments described have the same advantages as those combined with Figure 3 described exemplary embodiments. In the two hot water branches 10, 20, the output volume is lower than a pre-specified value; in particular, it is equal to or less than three liters. Since the water outlets 71, 72, 73, 74 are supplied by the two hot water branches 10, 20, the discharge capacity is higher than 20 l / min. Although less energy is required, the drinking water supply is stronger. The planning and implementation are also simplified because only one installation route needs to be set instead of the two installation routes required if two heating stations 50 are set for the two hot water branches. Even if the heating station 50 has the same or similar power consumption of 100 W as in the foregoing exemplary embodiment, providing stored thermal energy for the two primary circuits results in increased efficiency.

[0096] The components of the hot water system described above in connection with the figures can be provided by the manufacturer and then installed on site, especially in combination with a heat pump also used for heating drinking water. In such an embodiment, the components are optimized to operate with the heat pump. The drinking water heater 1 has very good efficiency because there is no turbulence or mixing caused by hot water flowing back into the hot water storage 3, as is the case with a circulation pipeline. The pipeline system 9 without a circulation pipeline results in high efficiency of the hot water system because the efficiency of the heat pump depends on the temperature gradient.

[0097] The features indicated above and in the claims, as well as the features visible in the figures, can advantageously be implemented individually and in various combinations. The invention is not limited to the described exemplary embodiments but can be modified in many ways within the capabilities of those skilled in the art.

[0098] List of reference numerals

[0099] 1 Drinking water heater

[0100] 3 Hot water storage

[0101] 9 Pipeline system

[0102] 11 Supply pipeline

[0103] 13 Distribution pipeline

[0104] 15 Heat exchanger

[0105] 17 Bypass valve

[0106] 19 Cold water pipeline

[0107] 21 House connection

[0108] 23 Booster

[0109] 31 Pressure regulator

[0110] 33 Instantaneous water heater

[0111] 49 Heat pump

[0112] 50, 51, 52 Hot water station

[0113] 60 Small hot water storage tank

[0114] 62 Thermal insulation part

[0115] 64 Heat exchanger

[0116] 66 Heating element

[0117] 68 Phase change material

[0118] 70, 71, 72, 73, 74 Water outlet station

[0119] 80 Micro thermal storage

Claims

1. A hot water system, comprising: - A drinking water heater (1) having a hot water storage tank (3); - Outlet stations (70, 71, 72, 73, 74); - A non-circulating pipeline system (9) between the drinking water heater (1) and the outlet stations (70, 71, 72, 73, 74), the non-circulating pipeline system (9) being designed such that heated drinking water flows from the drinking water heater (1) along a pipeline path in the pipeline system (9) to the outlet stations (70, 71, 72, 73, 74), wherein, the pressure in the pipeline system and the cross-sectional area of the pipes in the pipeline system depend on the length of the pipeline path such that the pipeline volume of the pipeline path is less than or equal to a predefined maximum pipeline volume, and wherein the pipeline path includes a first part and a second part, and hot water stations (50, 51, 52) are provided in the pipeline system (9) and between the first part and the second part, and are designed to heat and / or store the drinking water.

2. The hot water system according to claim 1, wherein, the first pressure in the first part and the first cross-sectional area of the pipes in the first part depend on the length of the first part such that the sum of the first pipeline volume of the first part and the second pipeline volume of the second part is less than or equal to the predefined maximum pipeline volume.

3. The hot water system according to claim 1 or 2, wherein, one or more additional outlet stations (70, 71, 72, 73, 74) are connected to the hot water stations (50, 51, 52), and wherein the pipeline volume in each pipeline path between the drinking water heater (1) and the additional outlet stations (70, 71, 72, 73, 74) or between the drinking water heater (1) and one of the additional outlet stations (70, 71, 72, 73, 74) is less than or equal to the predefined maximum pipeline volume, particularly less than or equal to three liters.

4. The hot water system according to any one of the preceding claims, wherein, if the length of the first part is at most 25 m or at most 35 m or at most 45 m or at most 65 m, the diameter of the first cross-sectional area of the pipes is less than or equal to 11.6 mm, particularly less than or equal to 9.6 mm, particularly less than or equal to 8.4 mm, and particularly less than or equal to 7 mm, and wherein if the length of the first part is at most 25 m or at most 35 m or at most 45 m or at most 65 m, the first pressure is greater than or equal to 0.71 bar, particularly greater than or equal to 2.47 bar, particularly greater than or equal to 6.01 bar, and particularly greater than or equal to 20.81 bar.

5. The hot water system according to any one of the preceding claims, wherein, a booster (23) is connected upstream of the drinking water heater (1).

6. The hot water system according to any one of the preceding claims, wherein, The hot water stations (50, 51, 52) include a pressure regulator (31), or the pressure regulator (31) is connected upstream of the hot water stations (50, 51, 52).

7. The hot water system according to any one of the preceding claims, wherein, the hot water stations (50, 51, 52) include a continuous flow heater (33) configured to heat water.

8. The hot water system according to any one of the preceding claims, wherein, the hot water stations (50, 51, 52) include a small hot water storage (60).

9. The hot water system according to claim 8, - wherein, the small hot water storage (60) has a heat insulator (62), - and / or wherein the small hot water storage (60) is designed to heat the water stored in the small hot water storage (60), - and / or wherein the small hot water storage (60) has a heat exchanger (64) with a phase change material (68).

10. The hot water system according to claim 9, - wherein, the heat exchanger (64) of the small hot water storage (60) has: two separate primary drinking water circuits (10, 20); and a secondary circuit including the phase change material (68).

11. The hot water system according to any one of the preceding claims, wherein, the hot water stations (50, 51, 52) include a bypass valve (17) which switches to the open state once hot water with a predefined minimum temperature is available on the inlet side of the hot water stations (50, 51, 52).

12. The hot water system according to any one of claims 8 to 11, wherein, at least one of the outlet stations (70, 71, 72, 73, 74) is provided with a micro hot water storage (80), the water storage capacity of the micro hot water storage (80) being lower than the water storage capacity of the small hot water storage (60).

13. The hot water system according to any one of the preceding claims, wherein, the pipeline system (9) has no fresh water station.

14. The hot water system according to any one of the preceding claims, the hot water system is a small system according to the German Drinking Water Ordinance, in particular according to DVGW worksheet W551.

15. The hot water system according to any one of the preceding claims, the drinking water heater (1) of the hot water system is connected to a heat pump (19), the heat pump (19) being designed to heat the water in the drinking water heater (1).

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