Heat transfer device

Abstract

A heat transfer device (540) comprises a first connection (545.1) for a cold water circulation line (20), a second connection (545.2) for a cold water circulation line (20), a third connection (545.3) for a hot water piping system line (30), a fourth connection (545.4) for a hot water piping system line (30), and at least one heat exchanger (543). The first connection (545.1) is fluid-conducted to the second connection (545.2) to form a first transfer line, and the third connection (545.3) is fluid-conducted to the fourth connection (545.4) to form a second transfer line.The first and second transmission lines interact with the at least one heat exchanger (543) in such a way that thermal energy can be transferred from the first to the second transmission line by means of the at least one heat exchanger (543). The heat transfer device (540) enables the transfer of thermal energy from the cold water circulation, in particular from its return flow, into the hot water piping system. In this way, the cold water can be cooled (if required) to maintain setpoints or meet user needs, while simultaneously utilizing the extracted energy.

Description

Technical field

[0001] The invention relates to a heat transfer device for a water supply system. It further relates to a water supply system with such a heat transfer device and a method for operating a water supply system. State of the art

[0002] Systems for supplying buildings with cold and hot water must meet a wide range of requirements. A key requirement is ensuring drinking water hygiene. This is jeopardized, among other things, by excessively high temperatures in the cold water supply and excessively low temperatures in the hot water supply. Furthermore, if target temperature ranges for cold and hot water are not maintained, this can lead to a reduction in user comfort.

[0003] Domestic cold water often has a temperature of more than 20°C, which is due to the following main factors: Hot and cold water pipes located close together without sufficient thermal insulation lead to heat transfer from hot to cold water; stagnation or low water movement in the cold water pipes due to the internal construction of buildings and longer periods without cold water consumption causes the water to heat up more; high room temperatures due to heating systems and warm climates lead to heating of the cold water pipes; and increased ground temperatures heat up the pipes to and in the buildings, especially in summer.

[0004] Especially when no cold water is drawn for an extended period, the water standing in the supply line gradually warms up due to the higher ambient temperature, and it can reach temperatures that are no longer within the hygienically safe range. Furthermore, users often run a considerable amount of drinking water before the desired cool water temperature is reached at the point of use. This results in additional drinking water consumption.

[0005] Similarly, the water in the hot water supply line cools down due to the lower ambient temperature. This also poses a risk of hygiene problems, and the user will drain a significant amount of water, resulting in corresponding additional consumption.

[0006] One approach to addressing these problems is the installation of a cold water circulation system and a hot water circulation system. These allow circulation even when no water is being drawn. The corresponding circulation pump can, for example, be controlled to activate for a predetermined period after a specified time without water being drawn. Continuous operation is also possible in principle.

[0007] On the cold water side, the recirculated water is usually mixed with freshly supplied cold drinking water from the building's water supply, resulting in further cooling. On the hot water side, the recirculated water is usually returned to the hot water storage tank and reheated, although mixing with heated water is also possible here.

[0008] Cold water recirculation allows for maintaining maximum target temperatures in the cold water supply. Furthermore, it improves user comfort because cold water, e.g., for drinking, is available at the point of use without any significant delay.

[0009] However, a particular problem arises on the cold water side: despite mixing, excessively high temperatures (which can be hygienically problematic and / or lead to a loss of comfort) can still occur at high ambient temperatures or comparatively high water temperatures in the cold water supply line, especially if there is insufficient water usage for extended periods, i.e., if the water stagnates. It should be noted that depending on the building's intended use and the activity patterns of its users, very different draw-off profiles result, some of which pose a greater risk of excessively high water temperatures than others.

[0010] Therefore, solutions exist in which the recirculated water is drained or in which cold water is actively cooled. However, the first option leads to an increased overall water consumption, and the second option is energy-inefficient.

[0011] Other solutions have been proposed: DE 10 2017 010 893 A1 (B. Miller) proposes a recirculation system in which hot and cold water pipes are connected to exchange the water without having to drain it, and in which the water circulates as needed via a small pump.

[0012] EP 3 159 457 B1 (Kemper GmbH & Co. Metallwerke Geb KG) discloses a drinking and process water supply system with a cold water circulation line and a heat exchanger that actively extracts heat from the water.

[0013] The EP 3 601 688 B1 (LTZ Zentrum für Luft- und Trinkwasserhygiene GmbH) describes a cold water circulation system with a cooling device and a circulation pump as well as a method for temperature and flow control based on temperature change models to ensure system temperatures below a specified value.

[0014] EP 1 626 034 B1 (G. Bauer) also proposes an active cooling device in a cold water circulation system, with which the water can be continuously cooled.

[0015] DE 10 2015 114 469 B3 (Viega GmbH & Co. KG) proposes a system for conveying cold drinking water, which includes a cooling section with a cooling line to improve hygienic conditions and efficiency.

[0016] The aforementioned solutions require electrical energy for the active cooling of the chilled water. The extracted heat is lost as waste heat. Overall, this results in reduced energy efficiency of the water supply system.

[0017] EP 2 966 384 A1 (Better Place GmbH) proposes a compact device for cooling a drinking water stream and transferring the recovered energy to another water stream. The device consists of two heat exchangers, an active heat transfer module, two circulation pumps, and four connections, all arranged on a common support or housing. The patent proposes connecting the device directly to the hot water circulation line to compensate for heat losses.

[0018] This allows the heat extracted from the cold water to be used in the water supply system, resulting in improved energy efficiency. However, integrating all components into a single housing limits the system's applications. Furthermore, the proposed system designs are not suitable for all locations; for example, problems can arise if the excess heat in the cold water line is significantly decoupled from the heat demand in the hot water system. Description of the invention

[0019] The object of the invention is to create a heat transfer device and a water supply system belonging to the aforementioned technical field, which ensure drinking water hygiene, are energy-efficient and can be used flexibly.

[0020] The solution to the problem is defined by the features of claim 1. According to the invention, the heat transfer device comprises a) a first connection for a cold water circulation line; b) a second connection for a cold water circulation line; c) a third connection for a hot water piping system line; d) a fourth connection for a hot water piping system line; and e) at least one heat exchanger.

[0021] Accordingly, a water supply system according to the invention comprises: a) a cold water circulation system; b) a hot water piping system with a hot water supply device and a hot water circulation system; and c) at least one heat transfer device according to the invention for transferring thermal energy from the cold water circulation system to the hot water piping system.

[0022] The first connection is fluid-conducted to the second connection to form a first transmission line, and the third connection is fluid-conducted to the fourth connection to form a second transmission line. The first and second transmission lines interact with the at least one heat exchanger in such a way that thermal energy can be transferred from the first transmission line to the second transmission line by means of the at least one heat exchanger.

[0023] In this context, a connection is a transition that fluid-conducts a section of the heat transfer device or the water supply system in which the heat transfer device is located. The connection can be physical, e.g., a screw, push-fit, or clamp connection. It can also be purely functional. The connection between the ports can be direct, but especially also indirect; that is, between a first port and a second port, which is fluid-conducted to the first port, additional components can be arranged besides the connecting or transfer line, e.g., valves, branches, pipe sections in heat exchangers, etc.

[0024] Cold water circulation is a piping system within the water supply system that allows cold water to circulate from the cold water inlet, through the risers to the floors, and back down again (ideally back into the system), even when no water is being drawn. A circulation pump is typically installed in this piping system for this purpose. Cold water circulation ensures that a certain maximum temperature, e.g., 25 °C according to the Swiss regulations SVGW-W3 / E3, SIA 385 / 1:2020, is not exceeded in the entire cold water piping system. A lower target temperature can also be set, preferably to further reduce the proliferation of germs such as Legionella spp. or to meet user needs, such as the need for cool drinking water.Tests have shown that lower temperatures, for example a maximum of 22 °C, preferably a maximum of 20 °C, and most preferably a maximum of 17 °C, significantly inhibit the growth of potentially dangerous germs, such as the rod-shaped bacterium Pseudomonas aeruginosa, which can cause serious infections of the ears, eyes, or wounds in people with weakened immune systems and can also lead to severe pneumonia or even blood poisoning. Accordingly, setting a lower target temperature for cold water distribution is particularly advantageous in hospitals and other care facilities.

[0025] The hot water piping system in this case can be a system with or without circulation.

[0026] A heat exchanger (also known as a heat transfer unit) is a device that transfers thermal energy (heat) from one transmission line to another, particularly without mass exchange or transfer. These are therefore preferably recuperators.

[0027] The heat transfer device according to the invention enables the transfer of thermal energy from the cold water circulation system, particularly from its return line, into the hot water piping system. This allows the cold water to be cooled (if required) to maintain setpoints or meet user needs, while simultaneously utilizing the extracted energy. No mass exchange between the cold water circulation system and the hot water piping system is necessary. No water loss occurs, as the returned water is reused in the cold water supply after cooling. Furthermore, this results in additional savings of drinking water because the waiting time for cold water is reduced, thus minimizing the amount of water that flows directly from the tap into the drain.

[0028] Overall, this results in improved drinking water hygiene and high user comfort with high energy efficiency and without additional drinking water consumption.

[0029] Preferably, the first and second transfer lines work together in the same heat exchanger to transfer thermal energy. This results in a particularly simple, cost-effective, and compact design. In the simplest case, thermal energy is transferred from the return line of the cold water circulation system to the supply line of the hot water supply unit. The latter is usually supplied directly by fresh water from an external source, which has a lower temperature than the return line of the cold water circulation system.

[0030] Valves can be provided to allow the first and / or second transmission line to optionally run through the heat exchanger or not (bypass). This increases the flexibility in operating the water supply system.

[0031] In one group of embodiments, the heat exchanger comprises at least one storage component, wherein thermal energy can be transferred from the first transmission line to the at least one storage component and from the at least one storage component to the second transmission line. This allows the absorption of thermal energy from the first transmission line and the release of thermal energy into the second transmission line to be decoupled in time. This is advantageous because the return flow in the cold water circulation and the water demand in the hot water piping system are not strictly correlated. Accordingly, the storage capacity of the at least one storage component and the transmission capacity of the heat exchanger must be selected such that the expected fluctuations can be accommodated.

[0032] Preferably, the storage component comprises a latent heat storage system. Thermal energy is stored in or extracted from a material that undergoes a phase change at a specific temperature under nearly isothermal conditions. The phase change material of the latent heat storage system particularly preferably has a melting point of 16-19 °C.

[0033] Latent heat storage systems require no external energy and do not need to be controlled or regulated. Due to their simple and closed design, they have a long lifespan.

[0034] Methyl myristate is particularly suitable as a phase change material on the cold water side. It has a melting point of approximately 17 °C.

[0035] Alternatives include other phase change materials (PCMs) such as caprylic acid, hexadecane, heptadecane, glycerol or KF-4H2O (potassium fluoride tetrahydrate) or mixtures thereof.

[0036] The temperature in the cold water side of the storage tank is particularly 15-20 °C.

[0037] A latent heat storage system can also be present on the hot water side. Sodium acetate trihydrate (SAT) is particularly suitable as a phase change material there. This liquefies at a temperature of 58 °C. The temperature in the hot water-side storage system is typically 55–65 °C.

[0038] In one group of embodiments, the first transmission line and the second transmission line interact with the at least one storage component. This again results in a simple, cost-effective, and compact design.

[0039] Alternatively, multiple storage components and means for transferring thermal energy between the storage components are available.

[0040] Preferably, at least one heat exchanger includes a heat pump. This allows for a substantial increase in the amount of transferable thermal energy, enables use across wider temperature ranges on both the cold and hot water sides, and allows for active cooling of the cold water if required. A heat pump is therefore particularly necessary when maintaining the maximum temperature at the building's cold water connection cannot be guaranteed at all times.

[0041] The heat pump operates primarily at low power, resulting in a long service life and minimizing noise. For a typical riser zone in a multi-story residential building, for example, a maximum continuous electrical power of 150 W, and in particular 100 W, is sufficient. The heat pump can be operated continuously or depending on the cold water return flow and / or parameters in the hot water piping system. Continuous operation at low power is facilitated by the presence of one or more storage components, especially latent heat storage systems, as this smooths out the heat transfer demand.

[0042] In certain embodiments of the invention, the heat pump interacts with at least one of the at least one storage component on at least one side. This allows the advantages of temporary thermal energy storage, a wider operating range, and a higher transferable energy quantity to be combined. Storage can take place on the cold and / or hot side.

[0043] Preferably, the relevant element of the heat pump, namely the evaporator and / or the condenser, is surrounded by the phase change material of the latent heat storage, so that the best possible transfer of thermal energy is achieved.

[0044] In another group of embodiments, the first transmission line interacts with a first side of the heat pump via a first storage component, and a second side of the heat pump interacts with the second transmission line via a second storage component.

[0045] Preferably, the heat transfer device comprises a housing, wherein the first, second, third, and fourth ports are formed on the housing, and the heat exchanger is arranged in the housing, and wherein a first circulation pump for cold water circulation and / or a second circulation pump for hot water circulation are arranged in the housing. In particular, both the first circulation pump and the second circulation pump are arranged in the same housing.

[0046] This creates a compact unit that can be easily integrated into a water supply system. If the heat exchanger includes a heat pump, the housing also incorporates power supply components and a control system. Standardized connection points are preferably provided on the housing, simplifying the retrofitting of existing systems. The housing is preferably thermally insulated to minimize heat transfer to and from the environment and soundproofed to prevent noise emissions.

[0047] The heat transfer unit can be modular, allowing the heat pump to be installed or even retrofitted as needed. The dimensions of the individual components, namely the heat exchanger, the storage component, the circulation pumps, and the heat pump itself, are adapted to the size of the water supply system (or riser zone) served by the heat transfer unit.

[0048] Preferably, the first and second connections are connected to the return line of the cold water circulation system and / or the supply line of the cold water circulation system, downstream of a connection point of the cold water circulation return line. This allows thermal energy to be extracted from the cold water circulation return line, thus cooling the cold water heated by the circulation.

[0049] The connection to the cold water circulation supply line enables active cooling of the potable water supplied at the building connection in heat transfer systems with a heat pump. This is advantageous when used in warm climates where the supplied potable water has a relatively high temperature.

[0050] The water supply system or heat transfer unit can be designed to switch between integration into the supply and return lines of the cold water circulation system, for example, by using a suitable valve arrangement and / or a pump with a reversible flow direction. This allows for flexible adaptation to varying conditions, such as seasonal variations, particularly regarding the temperature of the drinking water supplied at the building connection. In other configurations, the water supply system or heat transfer unit is permanently configured for one or the other connection, although the same heat transfer unit can generally be used for both applications, with the adjustment made during installation.

[0051] On the hot water side, various configurations are possible – as discussed below. With purely passive solutions without a heat pump, it is essential to ensure that heat transfer occurs from a higher temperature medium (the cold water circulation return) to a lower temperature medium (especially freshly supplied drinking water from the building's water connection, e.g., in the supply line to the hot water system). Using a heat pump opens up more possibilities.

[0052] In one group of embodiments, the third connection is connected to a supply for the hot water supply device, i.e., the water to be heated on the hot water side is in particular fresh cold water.

[0053] In another group of embodiments, the third connection is connected to a storage tank of the hot water supply device; that is, the water to be heated on the hot water side is taken from the storage tank. This arrangement has the advantage that the transferred thermal energy can be stored directly in the storage tank of the hot water supply device, regardless of the current hot water demand.

[0054] In another group, the third connection is connected to the return line of the hot water circulation; that is, the return line of the hot water circulation, which is cooler than the supply line, is heated using the heat transfer device.

[0055] In an advantageous embodiment, the water supply system includes a diverter valve by means of which medium from the third connection can be selectively supplied to the heat exchanger and / or directly to the supply or storage tank of the hot water supply system. The diverter valve is, in particular, part of the heat transfer device. It is designed, for example, as a temperature-dependent three-way mixing valve or as a motor-operated diverter valve. The water heated in the heat exchanger when the valve is in the appropriate position is preferably returned directly to the supply line of the hot water circulation system. However, it is also possible, for example, to return the water from the heat transfer device to the storage tank of the hot water supply system.The diverter valve can be designed as a control valve, allowing a first, controllable portion of the recirculated medium to be fed directly into the storage tank, while a second portion is supplied to the heat transfer unit for heating. This way, a portion of the heat losses from reheating can be covered by waste heat from the cold water. If sufficient waste heat is available, the entire volume can even be reheated. This ensures complete independence from the volume in the circulation loop that needs to be reheated. The remaining, uncovered volume is heated by the main heat generator of the hot water supply system.

[0056] If the third connection is connected to a supply line for the hot water supply unit, the fourth connection can also be connected to this supply line. Due to heat transfer, this results in a higher output temperature of the water supplied to the hot water supply unit. The overall energy requirement for hot water supply can therefore be reduced.

[0057] If the third connection is connected to a supply or storage tank of the hot water supply system, the fourth connection can also be connected to the storage tank. When water to be heated is drawn from the storage tank and returned, care must be taken to ensure that the temperature stratification within the tank is not disturbed as much as possible. This means that the outlet to the third connection and the supply from the fourth connection should be located at different heights within the tank. Disruption of the stratification would result in a loss of exergy. In principle, the height of the outlet and supply should be selected accordingly even if the other pipe is not directly connected to the storage tank.

[0058] The fourth connection can also be connected to a hot water circulation line. This allows heat losses in the hot water circulation to be compensated for. In this preferred embodiment, the introduction of heated water into the storage tank prevents the temperature stratification from being affected, which can lead to a significant loss of exergy. Furthermore, technical modifications to the storage tank are unnecessary. This also simplifies the subsequent modular conversion of an existing water supply system.

[0059] In this case, it is advantageous if the heat transfer device includes a storage component on the hot water side, as this allows for the intermediate storage of thermal energy until it is used in the hot water circulation.

[0060] In a preferred embodiment, the third connection is connected to a storage tank of the hot water supply system, and the fourth connection is connected to a supply line of the hot water circulation system. A temperature sensor for measuring the storage tank water temperature is located at a predetermined measuring point within the hot water supply system. The heat pump of the heat exchanger is activated when the measured storage tank water temperature falls below a predetermined first value and / or when a water temperature in the cold water circulation system exceeds a predetermined second value. The heat is thus transferred in a separate pipe segment to partially preheated hot water from the storage tank; this pipe segment then connects to the hot water supply line. This enables hydraulic separation of the hot water circulation system from the heat transfer unit.

[0061] The temperature sensor for measuring the storage water temperature is located, in particular, in an upper area of ​​the storage tank to detect the influence of water from the hot water circulation system. The return flow from the hot water circulation system to the storage tank is preferably arranged above the draw-off point in the reheating circuit.

[0062] In a preferred control method, a first target temperature is set in the storage tank (e.g., 55 °C), and the heat transfer device then additionally heats the medium to achieve a second, higher target temperature (e.g., 60 °C). Alternatively, the output of the main heat generator of the heat supply device is regulated depending on the temperature and water volume of the hot water circulation return flow.

[0063] In a preferred embodiment, the heat transfer device comprises a fifth port and a sixth port, wherein the fifth port is fluid-conducted to the sixth port to form a third transfer line, thermal energy being transferable from the first transfer line to the at least one storage component and from the at least one storage component to the third transfer line, and wherein the heat exchanger comprises a heat pump by which thermal energy is transferable from the at least one storage component to the second transfer line. In this way, the thermal energy from the cold water return can be transferred flexibly and according to demand in all operating states.

[0064] The invention particularly encompasses water supply systems in which the heat transfer device is designed and integrated as follows: variant Cold water circulation connection Latent heat storage (LWS) Heat pump (HP) Hot water circulation connection I Pre-run KW-LWS Yes no LWS feed line boiler II Return flow KW-WP no Yes Heat pump boiler III Pre-run KW-LWS Yes Yes i) LWS feed line boiler ii) Heat pump boiler IV Pre-run KW-LWS Yes Yes Heat pump recirculation DHW V Return flow KW-LWS1 yes (2x) Yes LWS2 recirculation feed WW

[0065] Variant I, without a heat pump, is characterized by its low complexity. It requires little space, no external energy for heat transfer, and can be easily integrated into existing water supply systems. Thanks to the LWS (low-temperature water supply system), the provision of thermal energy is decoupled from the heat demand. Implementation and operating costs are low.

[0066] Variant II with heat pump allows for more flexible operation, even with high heat demand.

[0067] Variants III, IV, and V, which include both a heat pump and a latent heat storage system, also enable flexible operation under a wide range of operating conditions of the water supply system. Due to the smoothing effect of the latent heat storage system on the temperatures, the heat pump can be operated particularly efficiently and quietly.

[0068] The water supply system can comprise several sections (e.g., riser zones), each with a cold water circulation and a hot water circulation, with the hot water circulations of the several sections being supplied by the same hot water supply device. In this case, a heat transfer device is preferably arranged in each of the sections between the respective cold water circulation and hot water circulation. The heat transfer thus occurs decentrally for each riser zone.

[0069] Particularly preferred is the heat transfer device of the section or riser zone furthest from the hot water supply device, i.e., located closest to it, i.e., at the beginning of the horizontal distribution, while the other heat transfer devices are located in the respective riser zone. This ensures that both cold and hot water in the garage or basement area remain cold or hot, respectively, right up to the cold water inlet or outlet of the hot water supply device.

[0070] In preferred embodiments, the cold water circulation system comprises a floor circulation line, which includes a supply section branching off from a branch point in a main cold water circulation line and leading to at least one draw-off point, and a return section leading from the at least one draw-off point back to a return point in the main line. This allows fresh water to be supplied to the floor even when no water is being drawn, ensuring that the cold water temperature does not exceed a predetermined maximum value.

[0071] In one implementation variant, the main line and the floor circulation line are designed such that the first pressure drop in the main line, between the branch point and the return point, is greater than the second pressure drop in the floor circulation line between the branch point and the return point. This ensures that a sufficient proportion of the circulating water is routed through the floor circulation line. The pressure differences can be achieved, for example, by installing restrictors between the point of use and the corresponding return point. The restrictor can be formed by a constriction and / or by a pipe section with a reduced cross-section.

[0072] In a second implementation variant, a controllable valve is arranged in the main line between the branch point and the return point to selectively block and / or throttle the flow. Preferably, the flow is blocked (or reduced) when at least one of the following criteria is met: a) the temperature in the assigned floor circulation line exceeds a specified maximum cold water value; b) a specified stagnation time has passed since the last circulation or the last water withdrawal.

[0073] With regard to criterion b), a timer is preferably triggered to temporarily block or throttle the controllable valve when water is drawn with a predetermined minimum volume (flush volume of the floor circulation) or when a flushing process is completed. After the timer expires, a flushing process takes place with a volume of water that is equal to or exceeds the flush volume of the associated floor circulation line.

[0074] Accordingly, a temperature sensor and a flow sensor are preferably present in the floor circulation line, and a control device for the controllable valve includes a timer circuit.

[0075] Preferably, the water supply system includes a control system designed to monitor at least two of the following parameters: a) a water temperature in the cold water circulation, b) a water temperature in the hot water circulation, c) a water temperature in the storage tank of the hot water supply device, d) a charge level of a storage component, The system is conditioned based on a daily consumption profile. This means that the parameters are adjusted in anticipation of demand to meet the required supply of cold and hot water within the appropriate temperature range. This adjustment is achieved by controlling at least some of the following components and parameters: i) Circulation capacity of the heat pump; ii) Output of the heating system of the hot water supply device; iii) Circulation capacities of the circulation pumps for cold and hot water circulation; iv) Position of any diverter and control valves (if applicable, also at the floor distribution level).

[0076] The daily consumption profile can be updated, particularly through self-learning, using data from a building automation system and / or temperature and flow sensors. Its creation can also be entirely self-learning, or it can start with a predefined profile that is then refined based on control and / or measurement data.

[0077] The daily consumption profile shows, for example, that there is an increased demand for hot water in the morning between 6:00 and 7:30 a.m. Accordingly, the system can be configured to fill the hot water storage tank with hot water at the target temperature by this time. Simultaneously, heat is stored in the heat transfer unit's storage tanks, which can be used to reheat the return flow of the hot water circulation system, or water from the storage tank, or water in the supply line to the storage tank, once hot water consumption has begun.

[0078] The control unit can be integrated into the housing of the heat transfer device, it can be designed as a standalone unit, or it can be integrated into another control system, e.g., building automation.

[0079] Preferably, the water supply system can be operated in a first operating mode in which thermal energy is transferred from the cold water circulation to the hot water piping system (specifically, to the flow line of the hot water supply unit) by the heat transfer device exclusively via a latent heat storage unit, and in a second operating mode in which the transfer of thermal energy from the cold water circulation to the hot water piping system via the heat transfer device is supported by the heat pump. The first operating mode is particularly advantageous at colder outside temperatures (e.g., autumn and spring) or when hot water demand is low, while the second operating mode is used at higher outside temperatures (e.g., in summer and in warmer climates) and / or when hot water demand is high. This minimizes the energy required for heat transfer.

[0080] The operation of the heat transfer unit is controlled primarily by measurements from temperature sensors distributed throughout the chilled water piping system. This ensures that the specified maximum temperature is maintained throughout the entire chilled water piping system. Control parameters from the following list are used in particular: Position of valves in the water supply system (control valves, shut-off valves); activation / deactivation and / or speed of the heat pump; operating parameters of the hot water supply device.

[0081] Further advantageous embodiments and combinations of features of the invention can be derived from the following detailed description and the entirety of the patent claims. Brief description of the drawings

[0082] The drawings used to illustrate the exemplary embodiment show: Fig. 1 a schematic diagram of a water supply system according to the invention; Fig. 2 a schematic diagram of a first embodiment of a water supply system according to the invention; Fig. 3 a schematic diagram of a second embodiment of a water supply system according to the invention; Fig. 4 a schematic diagram of a third embodiment of a water supply system according to the invention; Fig. 5 a schematic diagram of a fourth embodiment of a water supply system according to the invention; Fig. 6A a schematic diagram of a fifth embodiment of a water supply system according to the invention; Fig. 6B a schematic diagram of the fifth embodiment in a different operating mode for use at high temperatures of the drinking water supplied at the building connection; Fig. 6C a schematic diagram of a sixth embodiment of a water supply system according to the invention; Fig. 6D a schematic diagram of a seventh embodiment of a water supply system according to the invention; Fig.7. A diagram of a water supply system according to the invention with several riser zones; and Fig. 8A, B. Diagrams of cold water circulation with floor circulation.

[0083] Basically, identical parts in the figures are marked with the same reference symbols. Ways to implement the invention

[0084] The Figure 1Figure 1 is a schematic diagram of a water supply system according to the invention. The water supply system 1 comprises a cold water supply line 10, through which cold drinking water is supplied to the building. The cold water supply line branches into a cold water distribution system and a hot water distribution system. The cold water distribution system comprises a cold water circulation system 20, and the hot water distribution system comprises a hot water circulation system 30. Both circulation systems each include a supply line (riser) from which floor connections 21.1...4 for cold water and 31.1...4 for hot water branch off. Both circulation systems also include a return line, which can return water not used via floor connections 21.1...4 and 31.1...4 to the supply line of the respective circulation system by means of a circulation pump 22 for the cold water and a circulation pump 32 for the hot water. The circulation pump 22 orThe circulation pump 32 has a relatively low power consumption, in particular an electrical power consumption of 1–80 W, preferably 2–40 W, and most preferably 5–10 W. At such low power consumption levels, the pumps can be operated continuously without regulation. However, it is also possible to regulate the operation of the pumps based on measured variables, e.g., temperatures.

[0085] The volume of water in the cold water circulation system (supply and return) is typically 5–130 liters per riser section. The volume in the return line is usually small, as pipes with a relatively small cross-section (e.g., 16 mm diameter pipes) can be used in this section. The thermal mass in the riser is usually higher, but the circulation does not include the final distribution on the floor, as circulation is generally not provided in this area.

[0086] The cold water pipes of the water supply system are protected from condensation by suitable insulation, as is generally known. This prevents energy loss, ensures a dry system, and prevents corrosion.

[0087] The hot water supply system further comprises a hot water storage tank 11 with a heating element 12 for providing hot water. According to the invention, a heat transfer device 40 is arranged between the cold water circulation 20 and the hot water circulation 30, by means of which thermal energy can be transferred from the cold water circulation 20 to the hot water circulation 30.

[0088] Due to the higher temperature of the surrounding rooms, the cold water in the cold water circulation system 20 will warm up, e.g., from an initial temperature of 15 °C to 18 °C. Similarly, the hot water in the hot water circulation system 30 will cool down due to the lower temperature of the surrounding rooms, e.g., from 55 °C to 50 °C.

[0089] The operation and, if applicable, the configuration of the water supply system depend on environmental conditions and usage patterns. For example, the draw-off profiles in the corresponding riser zones have a significant influence on the temperature profiles in the cold and hot water circuits and at the draw-off points. Furthermore, the temperatures of the drinking water supplied at the building connection, the treated hot water, and the

[0090] Ambient temperatures in the vicinity of the pipes are significant. We assume the following temperatures in °C: Size Unit Area Preferred Especially preferred Water temperature at the building entrance (as delivered from the waterworks) °C 1 - 35 5 - 25 8-16 Cold water temperature in the cold water circulation line before the heat transfer unit °C 5 - 30 8 - 25 12 - 25 Cold water temperature at the point of use (target value for comfort, drinking water hygiene, compliance with standards) °C 5 - 25 12 - 20 15 - 18 Average ambient temperature (air) in the pipe shaft is often the same for both cold and warm areas, but this is not always the case. °C 10 - 50 16 - 35 20 - 30 Hot water temperature in the hot water circulation line before the heat transfer unit °C 40 - 70 45 - 65 55 - 60 Hot water temperature at the point of consumption (target value for comfort, drinking water hygiene, compliance with standards) °C 35 - 70 45 - 60 50 - 55

[0091] In principle, according to Figure 1 It is neither specified where in the cold water circulation 20 the energy is extracted, nor how the transfer takes place in the heat transfer device, nor where the energy is supplied to the hot water circulation 30. The following, in connection with the Figures 2-6 The illustrated examples show possible implementations.

[0092] The Figure 2Figure 1 is a schematic diagram of a first embodiment of a water supply system 100 according to the invention. The cold water supply line 10 is initially routed via a three-way valve 151 either via a first transmission line of a heat exchanger 141 of the heat transfer device 140 or directly into the supply line (riser) of the cold water circulation 20 (bypass).

[0093] A further branch of the cold water supply line 10 is routed via another three-way valve 153 either through a second transfer line of the heat exchanger 141 of the heat transfer device or directly into the supply line of the hot water storage tank 111 equipped with the heating element 112 (bypass). The heat exchanger 141 is embedded in a latent heat storage tank 142, and the first and second transfer lines are arranged such that heat transfer between the respective transfer line and the latent heat storage tank 142 is possible.

[0094] In the cold water circulation system 20, the return flow enters the supply line upstream of the three-way valve 151, so that the water flow, which is supplied to the supply line either directly or via the heat exchanger 141 through the three-way valve 151, consists of mixed water from the cold water supply line 10 and the return flow of the cold water circulation system 20. The amount of water circulated in the cold water circulation system 20 can be controlled by adjusting the circulation pump 122.

[0095] In the hot water supply system, depending on the position of the three-way valve 153, the fresh water is fed directly to the hot water storage tank 111 or via the heat exchanger 141. In the storage tank 111, it is heated (further) and then fed to the hot water circulation system 30. The amount of water circulated in the hot water circulation system 30 can be influenced by appropriate control of the circulation pump 132.

[0096] The latent heat storage unit 142 contains methyl myristate with a melting point of 17 °C as the phase change material. If the recirculated water mixed with the fresh water is warmer than 17 °C, this is detected by a temperature sensor 161, and the three-way valve 151 is positioned so that the mixed recirculated water is diverted into the heat exchanger 141. There, the phase change material melts and thus stores thermal energy. This leads to a cooling of the cold water line. In particular, it is ensured that the temperature of the cold water is below 20 °C, thus preventing the proliferation of pathogenic microorganisms such as Legionella spp. If the mixed water has a temperature below 17 °C at the first valve 151, it is fed directly into the supply line of the cold water circulation 20, thus preventing the cold water from warming up in the heat exchanger 141.

[0097] On the hot water side, if the temperature of the incoming water is below 17 °C, the three-way valve 153 can be set, again depending on measurements from a temperature sensor 162, so that the water is also directed through the heat exchanger 141. The phase change material freezes, and thermal energy is released, which heats the water for the supply line to the hot water storage tank 111. This results in a reduced heating requirement via the heating element 112. Should the incoming water temporarily have a temperature above 17 °C in the area of ​​the temperature sensor 161, it can be fed directly to the supply line for the hot water storage tank 111 via the bypass without the risk of it cooling down.

[0098] The Figure 3Figure 1 is a schematic diagram of a second embodiment of a water supply system 200 according to the invention. Here, the heat transfer device 240 comprises a heat pump 243 instead of the latent heat storage device. The heat pump 243 includes a coolant circuit in a manner known per se, wherein the coolant is evaporated in an evaporator 241a with the absorption of heat and condensed in a condenser 241b with the release of heat. The electrical power of the heat pump is, in particular, 20–500 W, more preferably 50–250 W, and most preferably 80–150 W.

[0099] In the embodiment according to Figure 3The fresh water supplied via the cold water supply line 10 is fed directly to the cold water circulation 20 or, via the hot water storage tank 211, to the hot water circulation 30. It is assumed that the temperature of the drinking water supplied at the building inlet is within a predefined setpoint range and, for example, no warmer than 20 °C. The return flow of the cold water circulation 20 is fed to an evaporator 241a of a heat pump 243 in the heat transfer unit 240. This unit, together with the circulation pump 222 and a delivery pump 246 for the hot water-side heat exchanger of the cold water circulation 20, is arranged in a housing. In the evaporator 241a, the recirculated cold water is cooled. Water drawn from the hot water storage tank 211 can be heated via the condenser 241b of the heat pump 243 and fed back into the hot water storage tank 211. In this device, the hot water is otherwise prepared using a heating element 212.The recirculated cold water, cooled in the heat transfer unit 240, can be selectively fed back into the cold water circulation system 20 or into the supply line to the hot water storage tank 211 via a three-way valve 255. The three-way valve 255 is controlled (among other things) by measured values ​​from a temperature sensor 263 and, if necessary, from other temperature sensors installed at key points along the cold water line. If the temperature is above 20°C, the water is directed to the hot water storage tank 211; otherwise, it is returned to the cold water supply.

[0100] The water pumped by the circulation pump 232 in the return line of the hot water circulation 30 is also fed to the hot water storage tank 211. Care is taken to ensure that the withdrawal and addition of liquids to and from the hot water storage tank 211 takes place at different levels, so that the temperature stratification of the stored water is disturbed as little as possible and exergy losses are minimized.

[0101] The heat transfer unit 240 is controlled here by means of speed control of the heat pump 243. This control can also be based, among other things, on the measured values ​​of the temperature sensor 263.

[0102] The Figure 4Figure 1 is a schematic diagram of a third embodiment of a water supply system 300 according to the invention. Fresh water from the cold water supply line 10 is fed into the cold water circulation system 20 on the one hand and either directly to the hot water storage tank 311 or through a latent heat storage tank 342 of a heat transfer device 340 on the other. A three-way valve 356 allows the flow through the latent heat storage tank 342 to be either included or bypassed. The supply line of the cold water circulation system 20 is also routed through the latent heat storage tank 342, after the return line of the cold water circulation system 20 connects to the circulation pump 322. Here, too, a bypass can be created using a three-way valve 351, so that the cold water is not routed through the latent heat storage tank 342.

[0103] The heat transfer unit 340 further comprises a heat pump 343, whose evaporator 341a is located in the latent heat storage tank 342, so that thermal energy can be extracted from the latent heat storage tank 342. Water extracted from the hot water storage tank 311 and conveyed by a circulation pump 346, also located in the heat transfer unit 340, can be additionally heated by means of the condenser 341b of the heat pump 343. The hot water circulation 30 is independent of the heat transfer unit 340: The hot water circulated by the circulation pump 332 is returned to the hot water storage tank 311.

[0104] The arrangement allows for flexible use of the latent heat storage unit 342 and the heat pump 343: If the temperature of the mixed water (return flow from cold water circulation / fresh water), as measured by a temperature sensor 361, exceeds 17 °C, it is used to charge the latent heat storage unit 342, thereby cooling the mixed water. If this temperature is below 17 °C, it flows directly through the bypass and not through the latent heat storage unit 342. Conversely, when hot water is required and the fresh water temperature is below 17 °C, the supply water for hot water preparation is first routed through the latent heat storage unit 342 so that it can be heated, thus reducing the energy requirement for the heating element 312 in the hot water storage tank 311. With the help of the heat pump, heat can be extracted from the latent heat storage unit 342 (and used for hot water production) at high fresh water temperatures, thus enabling cooling of the cold water in this case as well.

[0105] The Figure 5 Figure 4 is a schematic diagram of a fourth embodiment of a water supply system 400 according to the invention. As in the third embodiment, mixed water, formed from fresh water from the cold water supply line 10 and cold water recirculated from the cold water circulation 20 by means of a circulation pump 422, is selectively supplied to a latent heat storage device 442 or a heat transfer device 440. Here too, a bypass can be created by means of a three-way valve 451 so that the cold water is not passed through the latent heat storage device 442.

[0106] In contrast to the third embodiment, the fresh water is otherwise supplied directly to the hot water storage tank 411 with heating element 412.

[0107] The heat transfer unit 440 further comprises a heat pump 443, whose evaporator 441a is located in the latent heat storage tank 442, so that thermal energy can be extracted from the latent heat storage tank 442. The return flow of the hot water circulation system 30 can then be heated by means of the condenser 441b of the heat pump 443 to compensate for heat losses in the piping. The circulation pump 432 of the hot water circulation system 30 is located directly in the heat transfer unit 440, in a common housing with the latent heat storage tank 442 and the heat pump 443. The recirculated water heated in the heat transfer unit 440 is supplied to the hot water storage tank 411.

[0108] If the temperature of the mixed water (return flow cold water circulation / fresh water) detected by a temperature sensor 461 exceeds 17 °C, it is used to charge the latent heat storage unit 442, thereby cooling the mixed water. If this temperature is below 17 °C, it flows directly through the bypass and not through the latent heat storage unit 442.

[0109] When the latent heat storage unit 442 is charged and hot water from the return of the hot water circulation 30 flows through the heat pump 443, the evaporator 441a discharges the latent heat storage unit and the recirculated hot water is heated using the condenser 441b.

[0110] The Figure 6AFigure 5 is a schematic diagram of a fifth embodiment of a water supply system 500 according to the invention. This system comprises a heat transfer unit 540, in which a heat pump 543, two latent heat storage units 542 and 544, and the circulation pump 522 for the cold water circulation 20 and the circulation pump 532 for the hot water circulation 30 are integrated into a common housing. The heat transfer unit 540 can be connected to the cold water circulation 20 and hot water circulation 30 lines via connections 545.1...4. The heat transfer unit 540 thus forms a ready-to-connect unit.

[0111] On the cold water side, a first connection 545.1 is connected to the return line of the cold water circulation 20. Within the heat transfer unit 540, connection 545.1 is connected to a line that runs through the first latent heat storage tank 542 and then through the circulation pump 522 to the second connection 545.2. A line is connected to this second connection, which returns the recirculated water to the cold water supply, where it is initially mixed with fresh water from the cold water supply 10.

[0112] On the hot water side, a third connection 545.3 is connected to the return line of the hot water circulation 30. Within the heat transfer unit 540, connection 545.3 is connected to a line that runs through the second latent heat storage tank 544 and then through the circulation pump 532 to the fourth connection 545.4. A line is connected to this fourth connection, which returns the recirculated water to the hot water supply. This supply is otherwise provided by a hot water supply unit with a hot water storage tank 511 and a heating element 512. The return flow from the fourth connection 545.4 is downstream of the hot water storage tank 511.

[0113] The evaporator 541a of the heat pump 540 is located in the first, cold water-side latent heat storage tank 542, while the condenser 541b of the heat pump 540 is located in the second, hot water-side latent heat storage tank 544.

[0114] By controlling the heat pump 543, the heat transfer unit 540 can be operated in such a way that the cold water is kept below a set maximum temperature and the temperature loss in the recirculated hot water is compensated for. The latent heat storage units 542 and 544 take into account the fact that the cooling demand on the cold water side and the heating demand on the hot water side usually occur at different times.

[0115] The circulation pumps 522 and 532 are also controlled by temperature measurements taken directly in the heat transfer unit 540 and / or by external temperature sensors. Instead of controlling the circulation pumps, an adjustable circulation control valve can be used. This valve opens or closes depending on the water temperature in the return line of the respective circulation system. Such circulation valves are controlled electronically based on temperature measurements or thermostatically by means of an expansion element.

[0116] The Figure 6BFigure 500 shows the fifth embodiment of the water supply system 500 according to the invention in a different operating mode for use at high temperatures of the drinking water supplied at the building connection, such as those that occur particularly in warmer climates. In this case, the supplied drinking water is fed together with the water from the return line of the cold water circulation 20 via connection 545.2 to the heat transfer device 540. The circulation pump 522' then pumps the drinking water through the first latent heat storage tank 542, where heat is extracted from it. The cooled drinking water then enters the supply line of the cold water circulation 20. This ensures that a sufficient supply of cold water is available at the draw-off points in the building.

[0117] The operating modes according to the Figures 6A and 6Bcan basically be implemented with the same device, whereby either the delivery direction of the circulation pump 522, 522' is reversible or a valve arrangement is provided with which the connections 545.1, 545.2 can be connected to the circulation pump 522, 522' in different directions.

[0118] The Figure 6C Figure 1 is a schematic diagram of a sixth embodiment of a water supply system according to the invention. The sixth embodiment corresponds in many respects, particularly with regard to the cold water circulation 20 and the heat transfer device 540, to the fifth embodiment as described in Figure 2. Figure 6A The components are shown and described above. Therefore, a repetition of the description of these components is omitted.

[0119] The connection of the heat transfer device 540 to the hot water circulation system 30 and the hot water storage tank 511 differs. Similar to the second and third embodiments, water is drawn from the hot water storage tank 511 at a draw-off point, supplied to the heat transfer device via the third connection 545.3, and heated via the condenser 541b of the heat pump 543. The heated water is then fed into the supply line of the hot water circulation system 30, similar to the fifth embodiment. The return flow of the hot water circulation system 30 to the hot water storage tank 511 occurs at a discharge point that is located higher than the draw-off point for the water to be heated.

[0120] A temperature sensor for measuring the temperature of the stored water is located in an upper section of the hot water storage tank 511. A first target temperature is set for the water in the hot water storage tank 511 (e.g., 55 °C), and the heat transfer unit 540 then heats the water additionally to reach a second, higher target temperature (e.g., 60 °C) for the flow of the hot water circulation system 30.

[0121] In the sixth embodiment, heat is introduced in a separate pipe segment into partially preheated hot water from the hot water storage tank 511; the pipe segment then leads into the supply line of the hot water circulation 30. This enables a hydraulic separation of the hot water circulation 30 from the heat transfer device 540.

[0122] The Figure 6DFigure 1 is a schematic diagram of a seventh embodiment of a water supply system according to the invention. Again, the seventh embodiment corresponds in many respects, particularly with regard to the cold water circulation 20 and the heat transfer device 540, to the fifth embodiment as described in Figure 2. Figure 6A The components are shown and described above. Therefore, a repetition of the description of these components is omitted.

[0123] The connection of the heat transfer unit 540 to the hot water circulation system 30 and the hot water storage tank 511 differs. Water in the return line of the hot water circulation system 30 is routed via the third connection 545.3 and the corresponding circulation pump 532 to a controllable three-way valve 546, which, in this embodiment, is designed as a motor-operated control valve. This valve allows the flow rates from the return line to be controlled, on the one hand, via the condenser 541b of the heat transfer unit 540 and the fourth connection 545.4 into the supply line of the hot water circulation system 30, and on the other hand, via a fifth connection 545.5 to a supply point in the hot water storage tank 511.

[0124] The three-way valve 546 allows water from the third port to be selectively fed to the heat transfer unit 540 and / or directly to the hot water storage tank 511. When the valve is in the appropriate position, the water heated in the condenser 541b is returned directly to the supply line of the hot water circulation system 30. This allows a portion of the heat losses from reheating to be covered by waste heat from the cold water. If sufficient waste heat is available, the entire volume can even be reheated. This ensures complete independence from the volume of water in the hot water circulation system 30 that needs to be reheated. The remaining, uncovered volume is heated by the heating element 512 of the hot water supply unit.

[0125] The Figure 7Figure 1 is a schematic diagram of a water supply system according to the invention with several riser zones. These can be arranged in the same building or in several buildings. Each riser zone comprises a cold water circulation 20.1, 20.2, 20.3, 20.4 and a hot water circulation 30.1, 30.2, 30.3, 30.4. The cold water circulations 20.1...4 are supplied directly from a cold water supply 10, the hot water circulations 30.1...4 from a central hot water storage tank 610.

[0126] In the three riser zones closest to the water supply (and hot water preparation), a heat transfer device 640.1, 640.2, 640.3 is arranged at the lower end of each riser zone. These devices interact with the respective cold water circulation 20.1...3 and the respective hot water circulation 30.1...3. Each heat transfer device 640.1...3 ensures that the cold and hot water temperature requirements are met in the corresponding riser zone. Furthermore, unnecessary energy consumption is avoided through individual control of the circulation in each riser zone. Various measures can be taken to achieve this: a) autonomous operation of the individual circuits with circuit-specific circulation pumps of low power (e.g. 30 W or less, in particular 20 W or less); b) use of circulation control valves (electronically or thermostatically controlled) for temperature-dependent throttling of the circulation or to prevent unnecessary water circulation in the respective circuit, as long as the specified temperatures are maintained; c) combination of a) and b).

[0127] The circulation pumps related to the circuit according to measure a) can be controlled as required, in particular by means of temperature measurements in the area of ​​the circulation pump and / or at other points of the corresponding circulation (and optionally outside the circulation).

[0128] Measure b) will generally be unnecessary within the context of the water supply system according to the invention; therefore, additional circulation control valves can be omitted, resulting in reduced complexity and lower costs. However, particularly when retrofitting existing water supply systems with existing circulation control valves, these can continue to be used, either together with upstream circulation pumps or in combination with measure a).

[0129] The solutions mentioned can be used in both cold water circulation and hot water circulation.

[0130] The return lines of the cold water circulations 20.1...3 and the hot water circulations 30.1...3 flow into common return lines, which ultimately lead back to the starting point. A fourth heat transfer unit 640.4 is located in the water supply and hot water preparation area. It interacts with the return lines of the cold and hot water circulations 20.1...4 and 30.1...4 in the area of ​​the starting point, i.e., at the water supply / hot water preparation point.

[0131] The Figures 8A, 8B These are diagrams of cold water circulation with floor circulation. Figure 8AFigure 1 shows a first embodiment. The cold water circulation system 20 comprises, by way of example, two floor circulation lines 23.1, 23.2. These each branch off from the main branch of the cold water circulation system 20 at a junction point, are routed to the draw-off points, and return to the main branch via a return point. The lines are designed such that a pressure loss Δp12 Δp22 along the respective floor circulation line 23.1, 23.2 corresponds to the pressure loss Δp11 Δp21 in the main branch between the respective draw-off point and the return point. This ensures that circulation takes place in the floor circulation line 23.1, 23.2 even without water being drawn.

[0132] The Figure 8BFigure 2 shows a second embodiment. Similar to the first embodiment, the cold water circulation system includes, for example, two floor circulation lines 23.1, 23.2. These branch off from the main branch of the cold water circulation system 20 at a junction point, are routed to the draw-off points, and return to the main branch via a return point. An adjustable throttle valve 24.1, 24.2 is arranged between each draw-off point and the corresponding return point. This valve is controlled by an associated control unit 25.1, 25.2. Each control unit receives measured values ​​from a temperature sensor 26.1, 26.2 and a flow sensor 27.1, 27.2, each located in the associated floor circulation line 23.1, 23.2. The throttle valve 24.1, 24.2 is controlled based on these measured values.

[0133] The water supply system according to the invention further comprises several temperature sensors for recording the media temperatures at different locations in the cold and hot water distribution system. The temperature sensors can be connected via an IoT network to the control system of the heat transfer unit and / or a higher-level server. This enables, firstly, a high-resolution measurement of the water temperatures and thus verification that the target ranges are maintained throughout. Secondly, the measured values ​​allow for optimal control of the controllable system components, namely the circulation pumps, the valves, and the heat pump. Preferably, temperature sensors are integrated directly into the heat transfer unit, so that the required sensor technology is fully or largely available when only the heat transfer unit is installed in the water supply system.

[0134] The invention is not limited to the illustrated embodiments. For example, elements of different embodiments can be combined – in particular, the cold water side can be designed according to one example and the hot water side according to another example.

[0135] On the cold water side, the return flow from the cold water circulation can be cooled directly instead of the mixed water from the return and fresh water. This results in a lower cold water temperature, but in doing so, the advantages of the latent heat storage are only partially utilized.

[0136] On the hot water side, the designs according to the following are also possible. Figures 3-5 to compensate for heat loss in hot water circulation, with the advantage that intervention in the hot water storage tank is avoided and corresponding exergy losses can be prevented.

[0137] Furthermore, other embodiments besides the one according to Figure 6A in an operating mode according to Figure 6B Use for pre-cooling the drinking water before it is introduced into the cold water circulation system.

[0138] In embodiments where heat transfer occurs from the cold water circulation to the hot water circulation, heat recovery to the hot water storage tank can also be provided. This includes a corresponding hydraulic connection and a control system with sensors, a controller, and actuators. If the return of the dissipated energy to maintain the temperature in the cold water circulation to the hot water circulation causes the target temperature range in the hot water circulation to be exceeded, the excess heat can be selectively returned to the hot water storage tank using such heat recovery. If no such heat recovery is provided, the cooling of the cold water circulation can be temporarily reduced.This can lead to the temperature target range in the cold water circulation being temporarily exceeded, whereby the best possible compromise between excessively high cold water temperature and excessively high hot water temperature can be set with appropriate control.

[0139] In summary, the invention provides a heat transfer device and a water supply system that ensure drinking water hygiene, are energy-efficient and can be used flexibly.

Claims

1. Heat transfer device comprising: a) a first connection for a cold water circulation line; b) a second connection for a cold water circulation line; c) a third connection for a hot water piping system line; d) a fourth connection for a hot water piping system line; e) at least one heat exchanger, wherein the first connection is fluid-conducted to the second connection to form a first transfer line, and wherein the third connection is fluid-conducted to the fourth connection to form a second transfer line, and wherein the first transfer line and the second transfer line interact with the at least one heat exchanger in such a way that thermal energy can be transferred from the first transfer line to the second transfer line by means of the at least one heat exchanger.

2. Heat transfer device according to claim 1, characterized by the fact thatThe first transmission line and the second transmission line work together in the same heat exchanger to transfer thermal energy.

3. Heat transfer device according to claim 1 or 2, characterized by the fact that the heat exchanger comprises at least one storage component, in particular a latent heat storage unit, wherein thermal energy can be transferred from the first transmission line to the at least one storage component and from the at least one storage component to the second transmission line.

4. Heat transfer device according to claim 3, characterized by the fact that the storage component comprises a latent heat storage unit, wherein the phase change material of the latent heat storage unit preferably has a melting temperature of 16-19 °C, and wherein the phase change material is in particular methyl myristate.

5. Heat transfer device according to claim 3 or 4, characterized by the fact thatthe first transmission line and the second transmission line interact with the same at least one storage component.

6. Heat transfer device according to one of claims 1 to 5, characterized by the fact that which includes at least one heat exchanger and a heat pump.

7. Heat transfer device according to claim 6, characterized by the fact that The heat pump interacts with at least one storage component on at least one side.

8. Heat transfer device according to claim 7, characterized by the fact that The first transmission line interacts with a first storage component and a first side of the heat pump, and a second side of the heat pump interacts with a second storage component and the second transmission line.

9. Heat transfer device according to any one of claims 1 to 8, characterized bya housing wherein the first connection, the second connection, the third connection and the fourth connection are formed on the housing and the heat exchanger is arranged in the housing and wherein a first circulation pump for cold water circulation and / or a second circulation pump for hot water circulation are arranged in the housing.

10. Water supply system comprising: a) a cold water circulation; b) a hot water piping system with a hot water supply device and a hot water circulation; c) at least one heat transfer device according to any one of claims 1 to 9, for transferring thermal energy from the cold water circulation to the hot water piping system.

11. Water supply system according to claim 10, characterized by the fact thatThe first connection and the second connection are connected to the return line of the cold water circulation and / or the supply line of the cold water circulation, downstream of a junction of the return line of the cold water circulation.

12. Water supply system according to claim 10 or 11, characterized by the fact that the third connection is connected to a supply for the hot water supply device.

13. Water supply system according to claim 10 or 11, characterized by the fact that the third connection is connected to a storage tank of the hot water supply device.

14. Water supply system according to claim 10 or 11, characterized by the fact that the third connection is connected to the return line of the hot water circulation.

15. Water supply system according to claim 14, characterized bya diverter valve by means of which medium from the third connection can be selectively supplied to the heat exchanger and / or directly to the supply or storage of the hot water supply device.

16. Water supply system according to claim 12, characterized by the fact that the fourth connection is connected to a supply for the hot water supply device.

17. Water supply system according to one of claims 14 to 16, characterized by the fact that the fourth connection is connected to a storage tank of the hot water supply device.

18. Water supply system according to one of claims 12 to 17, characterized by the fact that the fourth connection is connected to a supply line for hot water circulation.

19. Water supply system according to claims 6, 13 and 18, characterized by the fact thatA temperature sensor for recording the storage water temperature is arranged at a predetermined measuring point in the storage tank of the hot water supply device, and the heat pump of the heat exchanger is activated when the recorded storage water temperature falls below a predetermined first value and / or when a water temperature in the cold water circulation exceeds a predetermined second value.

20. Water supply system according to one of claims 10 to 17, characterized by the fact thatThe heat transfer device comprises a fifth port and a sixth port, wherein the fifth port is fluid-conducted to the sixth port to form a third transmission line, wherein thermal energy can be transferred from the first transmission line to the at least one storage component and from the at least one storage component to the third transmission line, and wherein the heat exchanger comprises a heat pump with which thermal energy can be transferred from the at least one storage component to the second transmission line.

21. Water supply system according to one of claims 10 to 18, characterized byseveral sections, each with a cold water circulation and a hot water circulation, wherein the hot water circulations of the several sections are supplied by the same hot water supply device and wherein in each of the sections a heat transfer device is arranged between the respective cold water circulation and hot water circulation.

22. Water supply system according to one of claims 10 to 19, characterized by the fact that The cold water circulation includes a floor circulation line comprising a supply section that branches off from a branch point in a main line of the cold water circulation and leads to at least one draw-off point, and a return section that leads from the at least one draw-off point back to a return point in the main line.

23. Water supply system according to claim 20, characterized by the fact thatthe main line and the floor circulation line are designed in such a way that a first pressure drop in the main line, between the branch point and the return point, is greater than a second pressure drop in the floor circulation line between the branch point and the return point.

24. Water supply system according to claim 20, characterized by the fact that A controllable valve is arranged in the main line between the branch point and the return point to selectively block and / or throttle the flow.

25. Water supply system according to any one of claims 1 to 24, characterized bya control system designed to condition at least two of the following variables: a) a water temperature in the cold water circulation, b) a water temperature in the hot water circulation, c) a water temperature in the storage tank of the hot water supply device, d) a charge level of a storage component, based on a daily consumption profile, wherein the daily consumption profile is, in particular, self-learning and can be updated using data from a building automation system and / or temperature and flow sensors.

26. Method for operating a water supply system according to any one of claims 10 to 25, characterized by the fact thatIt is operable in a first operating mode in which the transfer of thermal energy from the cold water circulation to the hot water piping system by the heat transfer device takes place exclusively by means of a latent heat storage unit, and it is operable in a second operating mode in which the transfer of thermal energy from the cold water circulation to the hot water piping system by the heat transfer device is supported by the heat pump.

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