Retrofit kit for an existing central heating system and a method for retrofitting an existing central heating system using a retrofit kit

Abstract

Retrofit kit (1) for an existing central heating system (2), wherein the central heating system (2) comprises at least one primary heat source (3) operable by means of fuels, in particular a boiler and / or a gas boiler, at least one heat exchanger (4), preferably a radiator for heating a building, and at least one domestic hot water storage tank (5), wherein a heat transfer fluid (6), in particular water, can be heated by means of the primary heat source (3), wherein the heat transfer fluid (6) can be conveyed to and / or through the heat exchanger (4) by means of a heat pump (7), and wherein the heat transfer fluid (6) can be conveyed to the domestic hot water storage tank (5) for heating domestic hot water (9) temporarily stored in the domestic hot water storage tank (5), namely for heat transfer from the heat transfer fluid (6) to the domestic hot water (9) through or adjacent to the domestic hot water storage tank (5),wherein the primary heat source (3) has a central heating control and / or regulation device (10) for its control and / or regulation, wherein the retrofit kit (1) and / or the central heating system (2) has at least one electrically operated heat pump (11), wherein the heat transfer fluid (6) can be heated by means of the heat pump (11), wherein the heat transfer fluid (6) can be conveyed to and / or through the heat pump (11) for its heating, and wherein the heat transfer fluid (6) can be conveyed to and / or through the primary heat source (3) by means of the heating pump (7) and / or the storage pump (8), characterized in that the retrofit kit (1) has a temperature sensor (13.1) and a separate heat pump control and / or regulation device (14) for the heat pump (11), wherein the temperature sensor (13.1) is connected to the separate heat pump control and / or regulation device (14) for control / is connected or connectable via signal and / or data technology,wherein the heat pump (11) is connected and / or connectable to the separate heat pump control and / or regulation device (14) for control purposes, wherein the separate heat pump control and / or regulation device (14) is designed and / or implemented such that the heat pump (11) is controlled based on the actual domestic hot water temperature (T) measured by means of the temperature sensor (13.1) in a lower area of ​​the domestic hot water storage tank (5) or adjacent to this lower area of ​​the domestic hot water storage tank (5). B1 ) is controllable and / or adjustable, wherein the temperature sensor (13.1) is used as a first temperature sensor (13.1) for determining a first actual domestic hot water temperature (T B1 ) is implemented, wherein a second temperature sensor (13.2) is located in a vertically viewed middle or upper area of ​​the domestic hot water storage tank (5) for measuring and / or determining a second actual domestic hot water temperature (T B2) is arranged, wherein the second temperature sensor (13.2) is connected to the central heating control and / or regulating device (10) in a control / signal / and / or data-related manner, wherein the central heating control and / or regulating device (10) is designed and / or implemented such that the primary heat source (3) is adjusted depending on the second actual domestic hot water temperature (T B2 ) is controllable and / or adjustable, wherein the separate heat pump control and / or regulation device (14) is designed and / or implemented such that the heat pump (11) can be operated and / or activated for heating the heat transfer fluid (6) with the aid of the separate heat pump control and / or regulation device (14) when the first actual domestic hot water temperature (T) measured, determined and / or calculated with the aid of the first temperature sensor (13.1) B1 ) a first limiting temperature (T B1G ) falls below.

Description

[0001] The invention relates to a retrofit kit for an existing central heating system with the features of the preamble of claim 1 and a method for retrofitting an existing central heating system by means of a retrofit kit with the features of the preamble of claim 14.

[0002] Central heating systems currently in use and / or already known or present in buildings typically comprise a primary heat source, in particular a boiler and / or a gas-fired water heater, a heat exchanger, preferably a radiator or heating element for heating a building, and a domestic hot water storage tank. A heat transfer fluid, in particular water, can be heated by means of the primary heat source. A heat pump can circulate the heat transfer fluid, especially the previously heated fluid, through or to the heat exchanger. A storage pump can then circulate the heat transfer fluid to the domestic hot water storage tank for heating, in particular for heat transfer from the heat transfer fluid to the domestic hot water through or adjacent to the storage tank.The primary heat source includes a central heating control and / or regulation device for its control and / or regulation.

[0003] To save fuel when operating the central heating system described above, such systems can be expanded to include an electrically operated heat pump. Thus, a retrofit kit and / or a correspondingly expanded central heating system can then include at least one electrically operated heat pump. The heat transfer fluid can then also be heated by the heat pump. The heat transfer fluid can be pumped to the heat pump for heating, particularly with the aid of a circulation pump, or is circulated through the heat pump. Furthermore, the heat transfer fluid can also be pumped to the primary heat source by means of the heating pump, particularly the circulation pump, and / or the storage pump, whereby the heat transfer fluid can also be heated by the primary heat source.

[0004] German patent DE 30 49 132 C2 discloses a previously known, in this case oil-fired, central heating system with a boiler as the primary heat source and an integrated domestic hot water tank. A pipe leads from the boiler to a connection of a four-way mixing valve. From another connection of the four-way mixing valve, a heat transfer fluid, heated, for example, by the boiler, can be supplied by a heat pump to the heat exchangers / radiators to heat the building. A further pipe leads from the radiators back to the four-way mixing valve. This standard circuit of many central heating systems is now to be extended by a heat pump, for example, an air-to-water type. The heat pump is installed as part of a retrofit kit, in series with the boiler in the central heating system, ensuring proper flow characteristics.The retrofit kit includes a mechanically or electromagnetically operated shut-off valve, which allows the heat pump to be bypassed when installed. The heat pump can be easily and seamlessly connected to the existing central heating system. The existing four-way mixing valve can still be used. The retrofit kit also includes a circulation pump, which supplies heat transfer fluid to the heat pump when installed.

[0005] Domestic hot water boilers integrated into heating systems typically have a small storage capacity, meaning that the water must be heated quickly, i.e., with high power, when the central heating system is running. However, such high power consumption, especially when combined with a heat pump, requires the operation of the boiler, resulting in a high overall fuel demand throughout the year, which is disadvantageous and very expensive.

[0006] DE 32 30 940 A1 discloses a central heating system with a primary heat source designed as a boiler, a heat pump, and a domestic hot water storage tank for heating domestic hot water, with each of these components having its own pump and heating circuit. A heat transfer fluid can be supplied to the heat pump via a heat pump supply line, also called a return line, from, for example, an underfloor heating system. Several valves are provided so that various operating modes of the central heating system can be implemented using the boiler and the heat pump. The domestic hot water storage tank or the underfloor heating system can also be supplied with heated heat transfer fluid solely by the heat pump. Likewise, the domestic hot water storage tank or the underfloor heating system can also be supplied with heated heat transfer fluid solely by the boiler.Furthermore, simultaneous operation of the heat pump and boiler is also conceivable, in order to supply the underfloor heating system with appropriately heated heat transfer fluid via the heat pump and the boiler. In this case, the boiler is also supplied with the heat transfer fluid heated by the heat pump, with the heat pump and boiler thus connected in series via their valves. For economic reasons, the heat pump is not operated at outside temperatures below 5°C. 30-50% of the heat demand can be generated by the heat pump. A ready-to-install coupling unit, i.e., a hydraulic module, is provided, in which all connection points for linking the boiler to the heat pump and the associated heating circuits are located.The hydraulic module is either delivered fully connected and mounted directly on the back of the boiler, or it is delivered as a pre-installed hydraulic module that is then connected as a whole to the corresponding connections of the boiler.

[0007] The heating of the domestic hot water in the storage tank is not yet optimally designed. Simultaneous heating of the domestic hot water by the heat pump and the boiler is not possible with the valves and heating circuits described above. In particular, especially since the heat pump is only designed for 30-50% of the heating demand, the domestic hot water is heated solely by the boiler using expensive fuels from an early stage, thus increasing fuel consumption throughout the year.

[0008] EP 2 322 880 B1 discloses a heat pump system for a multi-family building with several residential units. Each residential unit has its own heat pump. The heat pumps are supported by auxiliary heating units. These auxiliary heating units can be, for example, conventional natural gas condensing boilers, i.e., so-called gas boilers. The auxiliary heating units are thus primarily designed as primary heat sources. The heat pumps can preheat a heat transfer fluid, which is then further heated in the auxiliary heating units connected in series. The heat transfer fluid is supplied to a heat exchanger, in particular a radiator, for heating a residential unit via a heating circuit. A bypass valve allows the heat transfer fluid to be bypassed around the heat exchanger. Alternatively, the auxiliary heating units could also be connected in parallel to the heat pumps.Depending on the required heating output, the heat pump can be operated monovalently (meaning without an additional auxiliary heater) or bivalently (meaning with an auxiliary heater). In monovalent operation, the residential unit is supplied with heating via the heat exchanger(s) / radiators and with domestic hot water solely by the heat pump. If the required heating output is higher than the maximum heating output of the heat pump, the heat pump operates bivalently. A distinction is then made between bivalent-alternative and bivalent-parallel operation. In bivalent-alternative operation, the heat pump covers the heating requirements of the residential unit up to a defined outside temperature. Below this defined outside temperature, the auxiliary heater covers the heating requirements alone. In bivalent-parallel operation, the heat pump covers the required heating output up to a defined outside temperature on its own.Below this outside temperature, the auxiliary heater is activated, so that both heat generators (heat pump and auxiliary heater) supply the living unit with heat simultaneously. In principle, the lower the outside temperature, the greater the contribution of the auxiliary heater to the total heating output. When using an air-source heat pump, the auxiliary heater supplies the living unit with heat on its own from a defined minimum outside temperature, as it is not economically viable to absorb heat from the outside air. In this case, the heat pump also serves as a connection point for the auxiliary heater, allowing a standard auxiliary heater to be mounted on top of it.

[0009] German patent DE 26 13 967 A1 discloses an installation element / hydraulic module for a bivalent central heating system consisting of a heat pump and an auxiliary heater (oil, gas, or electric). The auxiliary heater is thus designed as the primary heat source. The hydraulic module has several connections for the heat pump, the auxiliary heater, and a domestic hot water storage tank. Furthermore, several valves are arranged in or on the hydraulic module, e.g., a multi-way diverter valve for selectively supplying either a heat exchanger for heating a building or another heat exchanger for heating the domestic hot water. The piping for the components of the various heating circuits is also arranged in or on the hydraulic module.

[0010] German patent DE 195 27 830 C2 discloses a central heating system comprising, among other things, a primary heat source, an auxiliary heater (which can be configured as a heat pump), a radiator for heating a building, and a domestic hot water storage tank. The auxiliary heater has a heat exchanger and a diverter valve, which are combined into a hydraulic module with a surrounding housing. An auxiliary control unit is connected to a main controller of the primary heat source. The auxiliary heater is operated and regulated appropriately via corresponding control signals from the main controller to the auxiliary control unit.

[0011] From DE 10 2004 029 392 A1, a central heating system with a solar heating device and a fossil primary heat source for heating a quantity of water contained in a storage tank is known. To measure the water temperature in the storage tank, a storage tank temperature sensor with an electrically heated heating sleeve surrounding the sensor and a solar storage tank temperature sensor are arranged inside the tank. When sufficient solar energy is available, which is measured by a solar sensor, the storage tank temperature sensor is heated by the heating sleeve until the water temperature is simulated for the fossil primary heat source, exceeding the desired setpoint temperature of the fossil primary heat source.

[0012] From DE 102 45 571 B4, a hydraulic module for a central heating system is known. The central heating system has a primary heat source, a heat pump and two heat sinks, whereby the heat sinks can be designed as radiators, underfloor heating or also as a domestic hot water storage tank.

[0013] German patent application DE 26 13 967 A1 discloses a hydraulic module for a central heating system. The central heating system comprises a heat pump, a primary heat source, and a domestic hot water storage tank. A domestic hot water temperature controller is connected to the storage tank via a measuring line (capillary tube).

[0014] German patent application DE 196 48 652 A1 discloses a central heating system with a domestic hot water storage tank, a primary heat source, and a solar thermal system. Temperature sensors connected to a solar thermal controller are located in the domestic hot water storage tank. Additional temperature sensors connected to a further controller are also located in the domestic hot water storage tank. The domestic hot water can be heated via secondary heat exchangers separate from the storage tank, using both the solar thermal system and the primary heat source. The heated domestic hot water is then returned to the domestic hot water storage tank.

[0015] In conventional central heating systems, the heating of domestic hot water in the storage tank is not yet optimally designed when both a primary heat source and / or a heat pump (especially a retrofitted one) are used for heating the domestic hot water. As already described, a large amount of fuel is required throughout the year because the primary heat source must operate for extended periods to ensure that the actual domestic hot water temperature remains above a certain threshold.

[0016] Further problems arise, particularly when a heat pump is to be retrofitted and was not included in the original design of the central heating system. In such cases, very complex modifications to the central heating control unit are necessary to enable it to control the heat pump. Furthermore, the control unit must be specifically adapted to synchronize the heat pump's operation with the primary heat source. This is a very time-consuming process that must be repeated, especially when retrofitting a heat pump to an existing central heating system, as these systems often have significant differences.Ultimately, retrofitting an existing central heating system has proven problematic and is very labor-intensive and / or costly.

[0017] The invention is therefore based on the objective of providing a retrofit kit for an existing central heating system and / or a method for retrofitting an existing central heating system, or of designing and / or further developing such a method in such a way that fuel consumption and the associated costs are reduced, and / or the retrofit kit can be integrated into the existing central heating system in a simple and cost-effective manner using control and / or regulation technology, and / or retrofitting is possible without significant effort and / or installation costs.

[0018] This problem underlying the invention is now solved - for the retrofit kit - initially by a retrofit kit for an existing central heating system with the features of claim 1.

[0019] One aspect of the invention essentially consists in the fact that the retrofit kit comprises a temperature sensor and a heat pump control and / or regulation device, wherein the temperature sensor is connected or connectable to the heat pump control and / or regulation device via control, signal, and / or data transmission, and wherein the heat pump is connected and / or connectable to the heat pump control and / or regulation device via control transmission. A further aspect of the invention is that the heat pump control and / or regulation device is designed and / or configured such that the heat pump can be controlled and / or regulated depending on the actual domestic hot water temperature measured by the temperature sensor in a lower region of the domestic hot water storage tank (when viewed vertically) or adjacent to this lower region (when viewed vertically).

[0020] Because the retrofit kit now includes a separate heat pump control unit, the existing central heating control unit does not need to be adapted at all, or if it does, only to a very limited extent. In a preferred embodiment, the existing heat pump control unit can, for example, be designed to be specific to a particular heat pump, so that heat pumps of the same design and output could then be retrofitted to a wide variety of existing central heating systems using the same heat pump control unit. This initially simplifies the assembly of the retrofit kit components and / or avoids the need to adapt the heat pump control unit to differently designed heat pumps, although the latter is still conceivable.

[0021] Fuel savings and simplified integration of the components into the existing central heating system are initially achieved using the aforementioned temperature sensor. The desired domestic hot water temperature can then be precisely controlled and / or regulated by the retrofitted or existing heat pump and the retrofitted heat pump control unit. Because the temperature sensor is located in or adjacent to the lower section of the domestic hot water storage tank (vertically speaking), the heat pump can be controlled and / or regulated particularly quickly, without significant delay, when fresh, and therefore cold, water is drawn in.Colder (new) domestic hot water is fed back into the hot water storage tank, particularly due to the withdrawal of hot water from the storage tank (e.g., for a shower), as the supplied "new" hot water flows around the temperature sensor before mixing with the remaining hot water in the storage tank. The lower section of the hot water storage tank – viewed vertically – is preferably located in the lower third, or more specifically, the lower quarter, of the tank's total height, or is designed accordingly.

[0022] Regarding the term "domestic hot water storage tank," it should be briefly noted that this refers specifically to a water storage tank in which water is heated. The "domestic hot water storage tank" can therefore also be called a "hot water storage tank." The heated water is then drawn from the domestic hot water storage tank, for example, for showering, cooking, or washing dishes. Fresh water is then added to refill the domestic hot water storage tank. The designation of this tank as a "domestic hot water storage tank" does not mean that it stores used or contaminated water, but rather that the stored water is used for subsequent purposes, such as showering. Specifically, the domestic hot water storage tank stores and heats drinking water. This point should be emphasized.

[0023] In a highly preferred embodiment of the retrofit kit, the temperature sensor can be mounted, in particular by means of a T-piece, in or on a section of a domestic hot water supply line located between an inlet valve and an inlet connection of the domestic hot water storage tank. Such a T-piece is then also a component of the retrofit kit.

[0024] Opening the inlet valve allows fresh domestic hot water to be supplied to the hot water storage tank via the hot water inlet pipe and the inlet connection. Up to the inlet valve (viewed from the hot water storage tank), the hot water inlet pipe is functionally part of the hot water storage tank, as the hot water temperature here is comparable to that at the same level within the tank. Installing the temperature sensor on the hot water inlet pipe is particularly easy, as the hot water storage tank does not require any structural modifications, and the temperature sensor can still be installed, especially with direct contact to the freshly supplied hot water.In particular, a section of the domestic hot water supply line can be cut out and replaced with a T-fitting, with the temperature sensor then being arranged in the branch of the T-fitting and preferably connected to it with a cap. Alternatively, the T-fitting could be inserted into the domestic hot water supply line in such a way that a portion of the supply line is connected to the branch of the T-fitting, so that the temperature sensor is still arranged at one of the two parallel connections of the T-fitting, sealing this connection, and the temperature sensor preferably passes completely through the T-fitting. It is also conceivable and possible, on the other hand, to arrange the temperature sensor externally on or inside a housing / casing area of ​​the domestic hot water storage tank or the domestic hot water supply line.In this case, the installation of a temperature sensor, which can be placed on the outside of or inside a housing / jacket area of ​​the domestic hot water storage tank or on the domestic hot water supply line, would be particularly easy and quick.

[0025] The aforementioned temperature sensor serves as a primary sensor for determining the initial domestic hot water temperature. A second temperature sensor is located in a central or upper region of the domestic hot water storage tank (vertically speaking) to measure a second, preferably average, actual domestic hot water temperature. This second temperature sensor is connected to the central heating control and / or regulation unit via control, signal, and / or data transmission. The central heating control and / or regulation unit is designed and / or configured such that the primary heat source can be controlled and / or regulated based on the second actual domestic hot water temperature.In general, it should also be noted at this point that the term "connected in terms of control technology", which is used here and elsewhere, can also always include a signal and / or data technology connection.

[0026] The heat pump control and / or regulation device is now designed and / or implemented in such a way that the heat pump can be operated and / or activated for heating the heat transfer fluid with the aid of the heat pump control and / or regulation device when the first actual domestic hot water temperature measured, determined and / or calculated with the aid of the first temperature sensor, in particular by the heat pump control and / or regulation device, falls below a first limit temperature.

[0027] The central heating control and / or regulating device is designed and / or constructed in such a way that the primary heat source can be operated and / or activated for heating the heat transfer fluid with the aid of the central heating control and / or regulating device when the second actual domestic hot water temperature measured, determined and / or calculated with the aid of the second temperature sensor falls below a second limit temperature.

[0028] In a highly preferred embodiment, the first and second limit temperatures are selected in such a way that the primary heat source can only be operated and / or activated for heating the heat transfer fluid by means of the central heating control and / or regulating device when the heat demand of the domestic hot water storage tank exceeds a quantity of heat that can be provided by the heat pump at maximum output.

[0029] No further complex or complicated adjustments are necessary to control the central heating system, particularly the heating circuit for domestic hot water. The central heating control unit and the heat pump control unit operate essentially independently of each other. Specifically, the first temperature limit is entered into the heat pump control unit or is already defined there, and the second temperature limit is entered into the central heating control unit or is already defined there. The retrofit kit is therefore particularly quick to install and easily integrated into the central heating system from a control and / or regulation perspective.

[0030] The middle or upper section of the domestic hot water storage tank – viewed vertically – is preferably located in the upper two-thirds, and in particular in the upper half, of the tank's total height, or is designed accordingly. Furthermore, the clever and specific arrangement of the two temperature sensors enables optimal control and / or regulation of the entire central heating system with a view to minimizing fuel consumption for the primary energy source.The first temperature sensor is positioned – essentially in a vertical direction – below the second temperature sensor. Due to temperature stratification within the domestic hot water storage tank, the first sensor will detect a lower actual domestic hot water temperature than the second. However, a change in temperature, particularly a decrease in temperature, can be detected earlier with the first sensor than with the second. This provides the basis for optimally controlling the heat pump, in particular for preferentially operating it, and for activating and / or operating the primary heat source only when the output provided by the heat pump is sufficient.The amount of heat, especially to cover the demand for heating the domestic hot water storage tank, is no longer sufficient, so that the need for fuels for the primary heat source can be minimized or at least reduced.

[0031] The particularly fast controllability of the heat pump described above also means, in particular, that the heat pump can be activated and / or operated before the primary heat source when a corresponding heat demand from the domestic hot water storage tank is detected by the first temperature sensor. Any further heat demand from the domestic hot water storage tank is only detected later by the second temperature sensor. Specifically, the first and second limit temperatures are selected and / or set accordingly. For example, the first limit temperature is lower than the second limit temperature. Alternatively, the second limit temperature could also be lower than the first, in which case the second limit temperature would be, for example, 43°C, specifically in the range of 41°C to 45°C, while the first limit temperature would be, for example, 48°C, specifically in the range of 46°C to 50°C.

[0032] Preferably, the heat exchanger and the heat pump are connected in series with respect to the primary heat source and / or can be switched.

[0033] Preferably, an outlet connection of the heat pump is fluidically connected and / or connectable to an inlet connection of the primary heat source. This fluidic series connection allows all the heat transfer fluid heated by the heat pump to be supplied to the primary heat source during operation. This further reduces the fuel consumption of the primary heat source, as it rarely, if ever, needs to be activated or operated due to the relatively high temperature of the heat transfer fluid. Therefore, a desired temperature of the heat transfer fluid can usually be achieved within or near the primary heat source simply by heating the fluid with the heat pump, without requiring the primary heat source to be operated.

[0034] A heat exchanger inlet line is advantageously connected or connectable to the primary heat source on one side and to the heat exchanger on the other, in order to supply the heat transfer fluid to the heat exchanger via the heat pump through the inlet line, in particular where the heat exchanger inlet line is partly already present and partly part of the retrofit kit, especially part of a hydraulic module. A heat pump inlet line is connected or connectable to the heat exchanger on the one side and to the heat pump on the other, in order to supply the heat transfer fluid to the heat pump through the inlet line, in particular where the heat pump inlet line is partly already present and partly part of the retrofit kit, especially part of the hydraulic module.A heat pump drain line is fluidically connected or connectable to the heat pump and the primary heat source on the one hand, and to the primary heat source on the other, in order to supply the heat transfer fluid to the primary heat source through the heat pump drain line, in particular where the heat pump drain line is partly already present and partly part of the retrofit kit, in particular part of a hydraulic module.

[0035] This allows for particularly easy integration of the retrofit kit into the existing central heating system. The various lines of the retrofit kit are pre-assembled as required. Using these lines, the fluid-efficient series connection of the heat exchanger, heat pump, and primary heat source is especially easy to achieve. The lines mentioned here can be configured using pipes and / or hoses and / or flow channels formed within housings.

[0036] In another embodiment of the retrofit kit, the retrofit kit has at least one valve by means of which the heat transfer fluid can be directed and / or guided either from the primary heat source to the heat exchanger or past the heat exchanger to the heat pump.

[0037] Depending on the valve position, two different heating circuits can be created using the appropriately mounted valve. In a first heating circuit, the heat transfer fluid flows from the primary heat source, through the valve, through the heating pump, through the heat exchanger, through the heat pump, through the circulation pump, and back to the primary heat source. In a second heating circuit, the heat transfer fluid flows from the primary heat source, through the valve, through the heat pump, through the circulation pump, and back to the primary heat source. In a third heating circuit, the heat transfer fluid flows from the primary heat source, through the domestic hot water storage tank, through the storage pump, and back to the primary heat source. Preferably, a distribution system for the heat transfer fluid is provided in the primary heat source, in particular flow channels through which the heat transfer fluid flows.to which the heating circuits are connected and / or can be connected. The heat exchanger inlet line and the heat pump outlet line, as well as a line leading to and from the domestic hot water storage tank, are connected and / or can be connected to the primary heat source, in particular to such a distribution system, or are fluidically connected to the primary heat source, in particular a boiler.

[0038] Preferably, the retrofit kit comprises two 3 / 2-way valves, each with three connections and two switching positions: a first 3 / 2-way valve, which can be arranged or is arranged and / or interposed in the heat exchanger inlet line, and a second 3 / 2-way valve, which can be arranged or is arranged and / or interposed in the heat pump inlet line. The first 3 / 2-way valve is fluidically connected to the primary heat source and the heat exchanger, and is fluidically connected or connected to the second 3 / 2-way valve. The second 3 / 2-way valve is fluidly connected or connected to the heat exchanger, to the heat pump, and to the first 3 / 2-way valve.The first 3 / 2-way valve, when connected, allows the flow of heat transfer fluid either from the primary heat source to the heat exchanger or from the primary heat source to the second 3 / 2-way valve. The second 3 / 2-way valve, when connected, allows the flow of heat transfer fluid either from the heat exchanger to the heat pump or from the first 3 / 2-way valve to the heat pump.

[0039] The heating circuits described above can also be implemented using these two 3 / 2-way valves. Furthermore, the two 3 / 2-way valves are inexpensive to procure and easy to control and / or regulate. The two 3 / 2-way valves are preferably switchable from a neutral position to a switching position by means of an electric actuator, against a spring force applied by a mechanical spring, when the actuator is energized. The two 3 / 2-way valves are then installed in such a way that they do not need to be energized for extended periods during operation of the central heating system, thus saving energy accordingly.

[0040] Preferably, at least two elements and / or components from the group of elements / components, namely the heat exchanger inlet line at least in sections, the heat pump inlet line at least in sections, the heat pump outlet line at least in sections, the circulation pump, the heat pump control and / or regulation device and the valve, in particular the first 3 / 2-way valve and the second 3 / 2-way valve, but in particular the heat exchanger inlet line in sections, the heat pump inlet line in sections, the heat pump outlet line in sections, the first 3 / 2-way valve and the second 3 / 2-way valve, preferably all the aforementioned elements and / or components, and their respective associated connections are arranged and / or formed on a hydraulic module forming a common assembly.

[0041] Using such a hydraulic module greatly simplifies the installation of the retrofit kit on the central heating system. In particular, the otherwise common installation errors can be avoided, as the specific shape and / or design of the hydraulic module predetermines certain arrangements of elements and / or components. The hydraulic module is advantageously pre-assembled, for example, in a factory or at a heating contractor's facility, thus significantly reducing installation time for the end customer who operates the central heating system and wishes to retrofit it.

[0042] In another embodiment of the retrofit kit, the hydraulic module has a frame for connecting the hydraulic module to a building wall and / or the primary heat source. In this embodiment, the hydraulic module, and in particular the frame, is preferably adapted to the specific design of the primary heat source, so that the hydraulic module, and in particular the frame, can be easily mounted on the primary heat source or on a building wall.

[0043] In an advantageous embodiment of the retrofit kit, the portion of the heat exchanger inlet line belonging to the retrofit kit has a first connection for supplying the heat transfer fluid to the hydraulic module and a second connection for removing the heat transfer fluid from the hydraulic module. The portion of the heat pump inlet line belonging to the retrofit kit has a third connection for supplying the heat transfer fluid to the hydraulic module and a fourth connection for removing the heat transfer fluid from the hydraulic module. The portion of the heat pump outlet line belonging to the retrofit kit has a fifth connection for supplying the heat transfer fluid to the hydraulic module and a sixth connection for removing the heat transfer fluid from the hydraulic module.Preferably, the portion of the heat exchanger inlet line belonging to the retrofit kit, and / or the portion of the heat pump inlet line belonging to the retrofit kit, and / or the portion of the heat pump outlet line belonging to the retrofit kit are each integrated into the hydraulic module. The connections are aligned in such a way as to allow for a simple and quick connection to the pipe sections belonging to the central heating system.

[0044] The problem underlying the invention is also solved by a method for retrofitting an existing central heating system using the retrofit kit described above according to claim 14.

[0045] One aspect of the invention essentially lies in the fact that the first temperature sensor is mounted and / or arranged in or adjacent to a lower region of the domestic hot water storage tank (when viewed vertically). This first temperature sensor then allows the actual temperature of the domestic hot water in the lower region of the storage tank to be determined.

[0046] The retrofit procedure is therefore very easy to install. Positioning the temperature sensor in the lower section of the domestic hot water storage tank (vertically speaking) results in a cost-effective, uncomplicated, and, in particular, simple control and / or regulation of the entire central heating system, as already described. Furthermore, due to this lower position of the temperature sensor, only minor adjustments and / or settings are required on the existing heat pump control and / or regulation system, as well as on the existing central heating control and / or regulation system; in particular, no further adjustments and / or settings are necessary to operate the central heating system optimally.

[0047] Preferably, the first temperature sensor is then connected to the heat pump control and / or regulation unit via control, signal, and / or data transmission. The measured values ​​and / or signals determined by the first temperature sensor can then be transmitted to the heat pump control and / or regulation unit. The corresponding actual domestic hot water temperature is determined and / or calculated either by the appropriately designed temperature sensor itself or by the heat pump control and / or regulation unit. It is also conceivable that the first temperature sensor in the retrofit kit is already connected to the heat pump control and / or regulation unit via control, signal, and / or data transmission, particularly via a signal line. It should also be mentioned that corresponding wireless connections between the components are also possible.

[0048] Advantageously, if the heat pump is part of an existing central heating system, it is connected to the heat pump control and / or regulation unit. Alternatively, if the heat pump is part of a retrofit kit, it is connected to the heat pump control and / or regulation unit, or is already connected accordingly.

[0049] In particular, the heat pump control and / or regulation unit could also be located on the hydraulic module. Furthermore, it is conceivable that the heat pump control and / or regulation unit could be mounted separately, e.g., on a building wall. Alternatively, the heat pump and the heat pump control and / or regulation unit could also be designed as a single, integrated unit.

[0050] In a further embodiment of the method, the storage pump is then connected to the heat pump control and / or regulation unit. If necessary, an existing control connection between the storage pump and the central heating control and / or regulation unit is first disconnected and / or interrupted. Subsequently, the storage pump can be controlled and / or regulated by the heat pump control and / or regulation unit, thus enabling coordinated operation between the heat pump and the storage pump. In particular, the heat pump and the storage pump can then be activated and / or operated simultaneously and deactivated at the same time.In particular, the third heating circuit described above can then be operated accordingly for heating the domestic hot water, namely, in particular, a coordinated operation of the heat pump and the storage pump can take place.

[0051] It is also preferable to connect the heating pump to the heat pump control and / or regulation unit. In some cases, an existing control connection between the heating pump and the central heating control and / or regulation unit is first disconnected and / or interrupted. Subsequently, the heating pump can be controlled and / or regulated by the heat pump control and / or regulation unit, thus enabling coordinated operation between the heat pump and the heating pump. Specifically, the heat pump and the heating pump can be activated and / or operated simultaneously and deactivated at the same time. This also enables coordinated operation of the respective heating circuits.

[0052] In a further embodiment of the method, the valve is connected to the heat pump control and / or regulation unit via a control system. In particular, if the valve and the heat pump control and / or regulation unit are arranged on the hydraulic module, the control system connection is already implemented beforehand in a factory or by a heating contractor, so that this assembly step does not have to be carried out at the end customer's site.

[0053] In a further highly preferred embodiment of the method, the first 3 / 2-way valve and the second 3 / 2-way valve are each connected to the heat pump control and / or regulation unit via a control system. In particular, if the first and second 3 / 2-way valves and the heat pump control and / or regulation unit are arranged on the hydraulic module, the control system connection is implemented beforehand in a factory or at a heating contractor's facility, so that this assembly step does not need to be carried out at the end customer's site.

[0054] In a preferred embodiment of the method, an outdoor temperature sensor is mounted in an outdoor area surrounding a building, wherein the outdoor temperature sensor is or is connected to the heat pump control and / or regulation unit via control, signal, and / or data transmission. Thus, the components connected to the heat pump control and / or regulation unit can be controlled and / or regulated depending on the respective outdoor temperature.

[0055] Basically, the situation is that when operating the central heating system with the retrofit kit, the heat pump control and / or regulating device performs more control and regulating tasks than the central heating control and / or regulating device, whereby the heat pump control and / or regulating device performs some control and regulating tasks that were performed by the central heating control and / or regulating device before the integration of the retrofit kit.

[0056] Advantageously, the first limit temperature, or a table and / or a formula for determining the first limit temperature, is entered into the heat pump control and / or regulation unit and / or is already stored there. The second limit temperature, or a table and / or a formula for determining the second limit temperature, is entered into the central heating control and / or regulation unit and / or is already stored there.

[0057] In particular, by entering certain respective limit temperatures or by having desired limit temperatures, a coordination of the control and / or regulation of the heat pump with the control and / or regulation of the primary heat source is achieved or realized.

[0058] To simplify the procedure, the first and / or second limit temperatures are stored as constant values ​​in the heat pump control and / or regulation unit and / or in the central heating control and / or regulation unit, so that the first and second limit temperatures are independent of the outside temperature. Specifically, the first limit temperature is stored and / or set in the heat pump control and / or regulation unit, while the second limit temperature is stored or set in the central heating control and / or regulation unit.

[0059] In an advantageous embodiment of the method, the portion of the heat exchanger inlet line belonging to the retrofit kit is connected to the existing portion of the heat exchanger inlet line via the first and second connections of the hydraulic module. The portion of the heat pump inlet line belonging to the retrofit kit is connected to the existing portion of the heat pump inlet line via the third and fourth connections of the hydraulic module. The portion of the heat pump outlet line belonging to the retrofit kit is connected to the existing portion of the heat pump outlet line via the fifth and sixth connections of the hydraulic module. Subsequently, the heat transfer fluid can be supplied to the heat exchanger via the heat exchanger inlet line. Furthermore, the heat transfer fluid can then be supplied to the heat pump via the heat pump inlet line and to the primary heat source via the heat pump outlet line.Connections include, for example, flange fittings, which are connected, in particular by screwing, to corresponding counterparts already attached to or attaching to existing pipe sections. Alternatively, the retrofit kit's pipes could also be connected to the existing pipe sections in other ways, for example, by welding and / or soldering.

[0060] There are now numerous possibilities for advantageously designing and further developing the retrofit kit for an existing central heating system and the method for retrofitting an existing central heating system using a retrofit kit. Reference is made here to the claims subordinate to claim 1 and claim 14. In the following, a preferred embodiment of the retrofit kit according to the invention for an existing central heating system and the method according to the invention for retrofitting an existing central heating system using a retrofit kit will be explained and described in more detail with reference to the drawing and the accompanying description. The drawing shows: Fig. 1a in schematic representation a hydraulic circuit diagram of a first embodiment of the retrofit kit for an existing central heating system and the existing central heating system, Fig. 1b schematically shows a hydraulic circuit diagram of a second embodiment of the retrofit kit for an existing central heating system, Fig. 1c schematically represents a hydraulic circuit / connection diagram of a third embodiment of the retrofit kit for another existing central heating system and this existing central heating system, Fig. 2. A simplified schematic representation of a hydraulic circuit diagram of the first, second or third embodiment of the retrofit kit with the existing central heating system in the installed state. Fig. 3a schematically represents a domestic hot water storage tank for use in a central heating system in a side view, Fig. 3b schematically depicts a domestic hot water storage tank for use in a central heating system in a side view, with a different design than the Fig. 3a altered temperature stratification, Fig. 4. In schematic representation, a flowchart for a procedure for operating and / or controlling and / or regulating a heat pump in the installed state of the retrofit kit on the existing central heating system according to Fig. 2, Fig. 5. In schematic representation, a flowchart for a procedure for the operation and / or control and / or regulation of a primary heat source in the installed state of the retrofit kit on the existing central heating system according to Fig. 2, Fig. 6a in schematic representation a dependence of a first target heat transfer fluid temperature, a first limit temperature, a second target heat transfer fluid temperature or a second limit temperature on the outside temperature, wherein the first limit temperature is smaller than the second limit temperature, and Fig. 6b schematically represents a dependence of a first target heat transfer fluid temperature, a first limit temperature, a second target heat transfer fluid temperature or a second limit temperature on the outside temperature, where the first limit temperature is greater than the second limit temperature.

[0061] Fig. 1a to Fig. Figures 1c each show a schematic representation of a hydraulic circuit diagram of a first to third embodiment of the retrofit kit 1 for an existing central heating system 2. Fig. 1a and Fig. Figure 1c also shows the existing central heating system 2.

[0062] The central heating system 2 comprises at least one primary heat source 3, in particular a boiler and / or a gas-fired boiler, at least one heat exchanger 4, preferably a radiator or heating element for heating a building, and at least one domestic hot water storage tank 5. It should also be noted that the terms "primary heat source 3", "boiler", and in particular an oil-fired boiler or a gas-fired boiler are included.

[0063] A heat transfer fluid 6, in particular water, which can be conveyed through the depicted piping system, can be heated by means of the primary heat source 3. The heat transfer fluid 6, in particular previously heated fluid, can be conveyed through the heat exchanger 4 by means of a heating pump 7. The heat transfer fluid 6 can be conveyed to the domestic hot water storage tank 5 by means of a storage pump 8 for heating domestic hot water 9 temporarily stored in the domestic hot water storage tank 5, in particular for heat transfer from the heat transfer fluid 6 to the domestic hot water 9 through or adjacent to the domestic hot water storage tank 5. The primary heat source 3 has a central heating control and / or regulation device 10 for its control and / or regulation.

[0064] The retrofit kit 1 and / or the existing central heating system 2 includes at least one electrically operated heat pump 11, wherein the heat transfer fluid 6 can be heated by means of the heat pump 11. The essential components of each retrofit kit 1 are in Fig. 1a to Fig. 1c, each shown with a dashed line outline. According to the first and second embodiments of the retrofit kit 1 from the Fig. 1a and Fig. 1b the heat pump 11 is part of the respective retrofit kit 1. According to the third embodiment of the retrofit kit 1 from the Fig. 1c the heat pump 11 is already part of the existing central heating system 2.

[0065] The heat transfer fluid 6 can be conveyed to or through the heat pump 11 for heating, particularly with the aid of a circulation pump 12. The heat transfer fluid 6 can also be conveyed to or through the primary heat source 3 by means of the heating pump 7, particularly the circulation pump 12, and / or the storage pump 8.

[0066] Such a circulation pump 12 is according to the Fig. 1a to Fig. 1c is also designed as part of the retrofit kit 1. Alternatively, it would also be conceivable, particularly if the heat pump 11 is already part of the existing central heating system 2, that the circulation pump 12 is also part of the central heating system 2; however, the latter is not shown here.

[0067] Retrofit kit 1 includes a temperature sensor 13.1 and a heat pump control and / or regulation unit 14, wherein the temperature sensor 13.1 is connected or connectable to the heat pump control and / or regulation unit 14 via control, signal, and / or data technology. The heat pump 11 is connected and / or connectable to the heat pump control and / or regulation unit 14 via control technology. According to Fig. 1b the heat pump 11 in the retrofit kit 1 is already connected to the heat pump control and / or regulation unit 14 for control purposes. According to the Fig. 1a and Fig. 1c the heat pump 11 is not yet connected to the heat pump control and / or regulation device 14 in terms of control technology.

[0068] The heat pump control and / or regulation device 14 is designed and / or configured such that the heat pump 11 is controlled based on the actual domestic hot water temperature T measured by means of the temperature sensor 13.1 in a lower area of ​​the domestic hot water storage tank 5 or adjacent to this lower area of ​​the domestic hot water storage tank 5. B1 is controllable and / or adjustable.

[0069] In the Fig. Figure 2 shows the assembled state of the retrofit kit 1 with the existing central heating system 2 and the schematic representation of the domestic hot water storage tank 5 for use in the central heating system 2. Fig. 3a and Fig. 3b shows the position of the temperature sensor 13.1 in the - vertically viewed - lower area of ​​the domestic hot water storage tank 5 or adjacent to this - vertically viewed - lower area of ​​the domestic hot water storage tank 5.

[0070] The temperature sensor 13.1 could - in its mounted state - penetrate a wall of the domestic hot water storage tank 5 - viewed vertically - in the lower area of ​​the domestic hot water storage tank 50, so that a measuring area of ​​the temperature sensor 13.1 is then arranged or positioned within the domestic hot water storage tank 5 with direct contact to the domestic hot water 9 in the lower interior area of ​​the domestic hot water storage tank 5.

[0071] The temperature sensor 13.1 is according to Fig. 3a and Fig. 3b, in particular by means of a T-piece 15, in or on a section of a domestic hot water supply line 18 formed between an inlet valve 16 and an inlet connection 17 of the domestic hot water storage tank 5. Also in accordance with the Fig. 3a and Fig. 3b The measuring range of the temperature sensor 13.1 – in its mounted state – is in direct contact with the domestic hot water 9, which is located in the lower part of the domestic hot water storage tank 5. The T-piece 15 is according to Fig. 3a and Fig. 3b is interposed in the domestic hot water supply line 18 in such a way that a part of the domestic hot water supply line 18 is connected to a branch of the T-piece 15, so that the temperature sensor 13.1 is furthermore arranged at one of the two parallel connections of the T-piece 15 and closes this connection by means of a cap. The temperature sensor 13.1 preferably penetrates the T-piece 15 completely and is arranged according to Fig. 3a and Fig. 3b despite its arrangement at the T-piece 15 with its measuring range inside the domestic hot water storage tank 5. Alternatively, it would also be conceivable that the measuring range of the temperature sensor 13.1 is located within the domestic hot water supply line 18, in particular within the T-piece 15.

[0072] Alternatively, it would also be conceivable that the temperature sensor 13.1 – in its mounted state – is located on the outside of the wall of the domestic hot water storage tank 5, specifically in the lower area of ​​the domestic hot water storage tank 5, or on the outside of the domestic hot water supply line 18, whereby the actual domestic hot water temperature T is then determined B1 by means of the heat pump control and / or regulation device 14, preferably a temperature gradient occurring via the wall of the domestic hot water storage tank 5 or via a wall of the domestic hot water supply line 18 is then taken into account when determining the actual domestic hot water temperature.

[0073] Fluidically adjacent to the inlet valve 16, a check valve 16.r is integrated and / or arranged in the domestic water inlet line 18 or interposed here to prevent backflow of the domestic water 9 from the domestic water storage tank 5 into the domestic water inlet line 18 even when the inlet valve 16 is open.

[0074] The temperature sensor 13.1 is used here as a first temperature sensor 13.1 to determine a first actual domestic hot water temperature T. B1 A second temperature sensor 13.2 is installed in a vertically viewed, middle or upper area of ​​the domestic hot water storage tank 5 to measure a second, preferably average, actual domestic hot water temperature T. B2 arranged. The second temperature sensor 13.2 is connected to the central heating control and / or regulation unit 10 via control / signal / and / or data technology.

[0075] The central heating control and / or regulation device 10 is designed and / or implemented such that the primary heat source 3 is adjusted depending on the second actual domestic hot water temperature T B2 is controllable and / or adjustable.

[0076] The heat pump control and / or regulation device 14 is designed and / or configured such that the heat pump 11 can be operated and / or activated for heating the heat transfer fluid 6 with the aid of the heat pump control and / or regulation device 14, in particular when the first actual domestic hot water temperature T measured, determined and / or calculated with the aid of the first temperature sensor 13.1, in particular by the heat pump control and / or regulation device 14, is reached. B1 a first limiting temperature T B1GThe heat pump 11 and / or the circulation pump 12 continue to be controlled by the heat pump control and / or regulation unit 14, in particular additionally depending on a first actual heat transfer fluid temperature T formed at the outlet of the heat pump 11. W1 controlled and / or regulated. In particular, a first target heat transfer fluid temperature T is set for heat pump 11. W1, Soll The temperature set at the outlet of heat pump 11 should then be present. The initial actual heat transfer fluid temperature T falls below or exceeds this value. W1 the desired or specified and / or set first target heat transfer fluid temperature T W1, Soll , so the heat pump 11 is controlled and / or regulated accordingly, so that the first actual heat transfer fluid temperature T is then W1 then the target heat transfer fluid temperature T W1, Soll approximates, especially then the first actual heat transfer fluid temperatures T W1then again the first target heat transfer fluid temperature T W1, Soll , corresponding to the operation of heat pump 11. In particular, heat pump 11 is therefore also operated depending on a set and / or desired specific initial target heat transfer fluid temperature T. W1, Soll controlled and / or regulated. In particular, the desired and / or specified target heat transfer fluid temperature T is set. W1, soll depending on a particularly determined outside temperature T a and / or a desired room temperature of a room to be heated with the heat exchanger 4 is set and / or calculated, which will be explained again below.

[0077] The central heating control and / or regulating device 10 is designed and / or constructed such that the primary heat source 3 can be operated and / or activated for heating the heat transfer fluid 6 with the aid of the central heating control and / or regulating device 10 when the second actual domestic hot water temperature T measured, determined and / or calculated with the aid of the second temperature sensor 13.2 B2 a second limit temperature T B2G The primary heat source 3 continues to be controlled by the central heating control and / or regulation unit 10 depending on a second actual heat transfer fluid temperature T, which develops within or in the area of ​​the primary heat source 3. W2 controlled and / or regulated. In particular, the primary heat source 3 is additionally controlled depending on a desired and / or set second target heat transfer fluid temperature T. W2, Sollcontrolled and / or regulated. In particular, a desired and / or specific second setpoint heat transfer fluid temperature T is set using the central heating control and / or regulation unit 10. W2, Soll for the area of ​​primary heat source 3 and / or for its distribution system, wherein, when the second actual heat transfer fluid temperature T W2 below the desired and / or set second target heat transfer fluid temperature T W2, Soll If the temperature drops, then the primary heat source 3 is actively operated to reheat the heat transfer fluid 6 accordingly, in particular until the second actual heat transfer fluid temperature T is reached. W2 then the desired second target heat transfer fluid temperature T W2, Soll corresponds.

[0078] The first and second limiting temperatures T B1G , T B2GThe parameters are specifically chosen such that the primary heat source 3, with the aid of the central heating control and / or regulating device 10, can only be operated and / or activated for heating the heat transfer fluid 6 when the heat demand of the domestic hot water storage tank 5 exceeds the amount of heat that can be provided by the heat pump 11 at its maximum output. In simpler terms, the heat pump 11 will be operated with priority for as long as possible, i.e., it will operate before the primary heat source 3.

[0079] For example, the first limiting temperature is T B1G smaller than the second limiting temperature T B2G .

[0080] On the other hand, the second limiting temperature T could also be B2G smaller than the first limiting temperature T B1G be, whereby the second limiting temperature T B2G in particular 43°C, in particular in the range of 41°C to 45°C, whereby the first limiting temperature TB1G in particular 48°C and in particular in the range of 46°C to 50°C.

[0081] The two temperature sensors are designated as first and second temperature sensors solely for the sake of clarity. This designation does not imply any dependency between them and should not be considered restrictive. Another unambiguous designation for the two temperature sensors would be conceivable.

[0082] The processes for operating and / or controlling and / or regulating the heat pump 11 using the retrofit kit 1 mounted on the central heating system 2 according to Fig. 2 are based on a schematic representation of a flowchart according to Fig. 4 further clarifies this.

[0083] The system continuously checks whether the initial actual domestic hot water temperature T is... B1 below the first limit temperature T B1Gis located. If this is the case, process step V will be carried out. WP1 , namely the corresponding operation / control and / or activation of heat pump 11 is carried out. Heat pump 11 is then operated, in particular, until the first actual domestic hot water temperature T is reached. B1 again above the first limit temperature T B1G It is also conceivable that a first cut-off limit temperature T B1G' is provided which preferably 4°C to 6°C above the first limit temperature T B1G lies and the heat pump 11 is then operated in particular until the first actual domestic hot water temperature T is reached. B1 above the first cut-off limit temperature T B1G' is located. If the first actual domestic hot water temperature T B1 so the first limiting temperature T B1G or the first cut-off limit temperature T B1G' if exceeded, process step V will be WP2, namely a different operating mode and / or even the deactivation of heat pump 11. The procedure then starts again by checking whether the initial actual domestic hot water temperature T has changed. B1 below the first limit temperature T B1G The previously described procedures are carried out particularly when domestic hot water is drawn from the storage tank, for example for a shower, and then fresh, "colder" domestic hot water is added. The third heating circuit, specifically the storage pump 8, is activated simultaneously to heat the domestic hot water.

[0084] The processes for the operation and / or control and / or regulation of the primary heat source 3 using the retrofit kit 1 mounted on the central heating system 2 according to Fig. 2 are based on a schematic representation of a flowchart according to the Fig. 5 further clarified.

[0085] Here, the second actual domestic hot water temperature T is continuously checked. B2 below the second limit temperature T B2G' is located. If this is the case, process step V will be carried out. PR1 , namely the operation and / or activation of primary heat source 3. Primary heat source 3 is then operated, in particular, until the second actual domestic hot water temperature T is reached. B2 again above the second limit temperature T B2G It is also conceivable that a second cut-out limit temperature T exists. B2G' is provided which preferably 4°C to 6°C above the second limit temperature T B2G lies and the primary heat source 3 is then operated in particular until the second actual domestic hot water temperature T is reached. B2 above the second cut-off limit temperature T B2G' is located. If the second actual domestic hot water temperature T B2so the second limiting temperature T B2G or the second cut-off limit temperature T B2G' if exceeded, process step V will be PR2 , namely a different operating mode and / or the deactivation of primary heat source 3. The procedure then starts again by checking whether the second actual domestic hot water temperature T has changed. B2 below the second limit temperature T B2G The previously described procedure steps are carried out in particular when domestic hot water is drawn from the domestic hot water storage tank 5, e.g., for a shower, and new, "colder" domestic hot water is then supplied to the domestic hot water storage tank 5. The third heating circuit, in particular the storage pump 8, is activated simultaneously to heat the domestic hot water, or has already been activated, since the Fig. The four described procedural steps, in particular, must take place before the steps leading up to them. Fig. The process takes place in the 5 described steps. Simply put, the correspondingly implemented control system ensures that the heat pump 11 is preferentially controlled or used for heating the domestic hot water 9 before the primary heat source 3.

[0086] However, even in a “normal heating operation” of the central heating system 2, i.e. when the domestic hot water 9 does not need to be heated and, for example, only the heat transfer fluid 6 needs to be heated for the operation of the heat exchanger 4, the heat pump 11 can and always will be used preferentially before the primary heat source 3 to heat the heat transfer fluid 6, or activated and / or controlled accordingly; this should also be pointed out again.

[0087] In the highly preferred embodiment of the retrofitted central heating system 2, it is now ensured in particular that the primary heat source 3 is operated and / or activated for heating the heat transfer fluid 6 by means of the central heating control and / or regulating device 10 only when the heat demand of the heat exchanger 4 and / or the domestic hot water storage tank 5 exceeds a quantity of heat that can be provided by the heat pump 11 at maximum output. Such a heat demand of the heat exchanger 4 also depends in particular on a desired room temperature of a room to be heated by the heat exchanger 4. It is conceivable that such a desired room temperature is selected by a user of the room to be heated and is subsequently available in the heat pump control and / or regulating device 14 for controlling and / or regulating the heat pump 11. One could also say that the first target heat transfer fluid temperature TW1 , Soll then depends on the desired room temperature. If the heat pump 11 is controlled and / or regulated based on the desired room temperature, this is also referred to as modulating operation of the heat pump 11.

[0088] During operation of the domestic hot water storage tank 5, a vertical temperature stratification of the domestic hot water 9 develops within the domestic hot water storage tank 5. The first actual domestic hot water temperature T B1 The temperature is measured – viewed vertically – in a lower, first temperature layer. The second actual domestic hot water temperature T B2 The temperature is measured – viewed vertically – in a middle or upper, second temperature layer. The first temperature layer forms vertically below the second temperature layer. This temperature stratification is found in the Fig. 1a, Fig. 1c as well as 2 and in Fig. Figure 3a shows exemplary temperatures between 30°C in the first, lowest temperature layer and 45°C in the uppermost temperature layer.

[0089] These in Fig. The temperature stratification shown in 3a, between 30°C in the first, lowest temperature layer and 45°C in the uppermost temperature layer, occurs particularly when the first limit temperature T B1G smaller than the second limiting temperature T B2G is and then especially T B1G = 30°C and T B2G < 40° C, especially T B2G The temperature is selected between 35°C and 38°C.

[0090] If the second limit temperature T B2G smaller than the first limiting temperature T B1G is, in particular, the second limiting temperature T B2G in particular 43°C, in particular in the range of 41°C to 45°C, and the first limiting temperature T B1GIf the temperature is particularly 48°C and especially lies in the range of 46°C to 50°C, then a particular situation arises in Fig. 3b shows a temperature stratification between 50°C in the first, lowest temperature layer and 60°C in the uppermost temperature layer.

[0091] From the Fig. 3a and Fig. 3b The temperatures shown in the individual layers there are in particular an average temperature for the respective layer.

[0092] The first actual domestic hot water temperature T B1 It therefore exhibits particularly lower values ​​than the second actual domestic hot water temperature T. B2, when the domestic hot water 9 remains at rest in the domestic hot water storage tank 5 for a certain period of time. The temperature stratification can change when domestic hot water 9 is drawn from the domestic hot water storage tank 5, particularly from its upper region, and / or "new" domestic hot water 9 is then supplied back to the domestic hot water storage tank 5, particularly from its lower region, whereby a corresponding temperature stratification can generally be maintained within the domestic hot water storage tank 5 by means of an appropriate discharge and supply concept.

[0093] Because of this, in the domestic hot water storage tank 5, a [something] is located in the Fig. 1a, Fig. 1c, Fig. The formation of a recognizable and depicted temperature stratification as shown in 2 3a and 3b essentially ensures that the first actual domestic hot water temperature T B1 below the second actual domestic hot water temperature T B2 The service water 9, especially as also in the Fig. As shown in Figures 2, 3a, and 3b, the area of ​​the first, lower temperature sensor 13.1 can be supplied to the domestic hot water storage tank 5. If, compared to the domestic hot water 9 already present in the domestic hot water storage tank 5, fresh, cold domestic hot water 9 is now supplied to the domestic hot water storage tank 5, the first actual domestic hot water temperature T will initially be reached. B1 drop. The second actual domestic hot water temperature T B2 will only drop later, especially when the fresh, cold service water 9 or its temperature has spread to the second temperature sensor 13.2.

[0094] The first limiting temperature T B1G When cold domestic water is supplied, 9, with appropriate selection of the limit temperature values ​​T, B1G , T B2G always relative to each other from the corresponding first actual domestic hot water temperature T B1 must be undercut before the second limit temperature T B2G through the second actual domestic hot water temperature TB2 The required temperature will fall below the setpoint, so that heat pump 11 is always operated / controlled and / or activated before the primary heat source 3. If the output of heat pump 11 is then sufficient to cover the heat demand of the domestic hot water storage tank 5, the second actual domestic hot water temperature T will be determined. B2 not below the second limit temperature T B2G The temperature drops, and primary heat source 3 does not need to be activated and therefore does not need to be operated with fuel combustion. The values ​​of the limit temperatures T B1G , T B2G are chosen in particular so that these processes take place as described and the primary heat source 3 is activated neither too early nor too late in order to save fuel and ensure a comfortable temperature for the domestic hot water 9 taken from the domestic hot water storage tank 5.

[0095] The first limiting temperature T B1G is either below the second limit temperature T B2Gas in Fig. 6a is shown or the first limiting temperature T B1G lies above the second limit temperature T B2G as in Fig. 6b is shown, where in the case that T B1G <T B2G is, in particular, when the temperature stratification according to Fig. 3a sets and in the case that T B1G >T B2G or T B2G <T B1G is, in particular, the temperature stratification according to Fig. 3b is set. In the first case mentioned above, the first limit temperature T is set. B1G especially at 30°C and the second limit temperature T B2G < 40° C, especially T B2G set between 35°C and 38°C. In the second case mentioned above, the first limit temperature T B1G especially in the range of 46°C to 50°C, especially set to 48°C and the second limit temperature T B2Gin the range of 41°C to 45°C, specifically set to 43°C, as previously described and / or explained. The second limit temperature T can be used here. B2G then, in particular, set 3°C ​​to 7°C, especially 5°C lower than the first limit temperature T. B1G .

[0096] To set / initiate optimal temperature control and / or regulation for heating the domestic hot water 9 in the domestic hot water storage tank 5, the following steps are initially carried out: Particularly after the installation of the system and / or before the system is put into operation, the domestic hot water storage tank 5, initially completely filled with "cold" domestic hot water 9, is first heated "only" by the primary heat source 3, or rather, the domestic hot water 9 is heated only with the help of the heat transfer fluid 6 heated by the primary heat source 3. The heat pump 11 remains switched off during this phase. After reaching the desired second actual domestic hot water temperature T, B2 , i.e., only when the desired second actual domestic hot water temperature T is reached. B2The heat pump 11 is switched on or activated only after the temperature is determined by the second temperature sensor 13.2. This occurs at the point when the desired domestic hot water temperature 9 or the desired second actual domestic hot water temperature T is reached. B2 Once the temperature at the second temperature sensor 13.2 has been reached or determined, then the current first actual domestic hot water temperature T at the first temperature sensor 13.1 is used. B1 measured. For the control of heat pump 11 for the further operation of the system, the first target heat transfer fluid temperature T is then determined. W1, Soll For the control and / or regulation of the heat pump 11, it is set to a value that is essentially 5°C higher than the first actual domestic hot water temperature value T mentioned above and determined. B1 The second target heat transfer fluid temperature T W2, Soll In particular, it is set to a value 7°C to 9°C, preferably 8°C lower than T. W1, SollSuch a system setting prevents unnecessary operation of the primary heat source 3, whereby, in particular, the heat pump 11, as previously described, is sufficient to heat the domestic hot water 9 present in the domestic hot water storage tank 5 accordingly, without requiring operation of the primary heat source 3. The first and / or second limit temperature T B1G or T B2G The temperature will then be reduced by 2°C to 5°C in each case compared to the respective corresponding determined or desired first and second actual domestic hot water temperatures T. B1 or T B2 set or then automatically calculated by the heat pump control and / or regulation unit 14.

[0097] In particular with reference to Fig. 3b may now be stated again as follows: It is also conceivable that the second limit temperature T B2G is set lower than the first limit temperature T B1GFor example, T B1G set to 49°C and T B2G set to 43°C. In particular, this results essentially in a temperature stratification as well as in Fig. Figure 3b illustrates this. The domestic hot water storage tank 5 achieves a discharge temperature of 60°C in the uppermost layer, thus initially providing protection against bacteria and Legionella. Furthermore, the... Fig. 3b evident stratification at the same time significantly increases the usable heated water quantity of the domestic hot water 9 in the domestic hot water storage tank 5 (compared to Fig. 3a), in particular since the domestic hot water 9 of the domestic hot water storage tank 5 is now essentially heated down to the lowest layer, or the domestic hot water 9 located there is heated / heated accordingly. However, since the usable amount of heated water is now, for example, in comparison to Fig. 3a, in Fig. 3b is now increased, the heat pump 11 can, even if the first actual domestic hot water temperature T B1 the first limiting temperature T B1G If the temperature falls below a certain threshold, the system will operate with a specific lockout period. Or, to put it another way, only after a certain lockout period has elapsed will the domestic hot water 9 in the domestic hot water storage tank 5 be heated again using the heat pump 11, which will then be active. This reduces the required cycling frequency of the heat pump 11; in particular, a setting of T contributes to this. B2G < T B1G also ensures that the primary heat source 3 only contributes to heating the domestic hot water 9 in the domestic hot water storage tank 5 when the second actual domestic hot water temperature T B2 the second limit temperature T B2GThis falls below the setpoint, which is only the case in particular when a correspondingly large quantity of already heated domestic hot water 9 has been or is being drawn from the domestic hot water storage tank 5, for example, by a large number of simultaneous showers in an apartment building. Blocking times of 15 to 30 minutes are possible for the heat pump 11.

[0098] The heating pump 7 is activated, in particular depending on an outside temperature T measured by means of an outside temperature sensor 13.a. aThe heating pump 7 is controlled and / or regulated by means of the heat pump control and / or regulation device 14. In particular, the heating pump 7 is initially operated and / or activated synchronously with the heat pump 11 when the storage pump 8 is switched off, especially when it is deactivated. This synchronous control is made possible in particular by the fact that both the heating pump 7 and the heat pump 11 are controlled and / or regulated by means of the heat pump control and / or regulation device 14.

[0099] The heating pump 7 is switched off, or in particular deactivated, by means of the heat pump control and / or regulation unit 14 when the storage pump 8 is operated and / or activated by the heat pump control and / or regulation unit 14, particularly due to the withdrawal of domestic hot water 9 from the domestic hot water storage tank 5. This allows the domestic hot water 9 to be reheated more quickly after withdrawal from the domestic hot water storage tank 5, as well as after and / or during the supply of fresh, cold domestic hot water 9 with the help of the heat transfer fluid 6. Alternatively, the heating pump 7 and the storage pump 8 could also be operated simultaneously, but in order to heat the domestic hot water 9 in the domestic hot water storage tank 5 within the same time, a correspondingly high output would have to be provided by the heat pump 11 and / or the primary heat source 3.Operating the heating pump 7 and the storage pump 8 simultaneously is also referred to as "parallel" operation of the central heating system 2. In "parallel" operation, simultaneous heating of the building and the domestic hot water 9 is then possible.

[0100] The heat exchanger 4 and the heat pump 11 are connected in series with respect to the primary heat source 3, in particular according to flow engineering principles. Fig. 2 switched or switchable and / or according to the Fig. 1a to Fig. 1c connected in series or switchable.

[0101] Thus, the heat transfer fluid 6, preheated by means of the heat pump 11, can be fully supplied to the primary heat source 3 in the installed state of the retrofit kit 1 on the central heating system 2.

[0102] A heat exchanger inlet line L WT, zuis fluidically connectable or connected to the primary heat source 3 on the one hand and to the heat exchanger 4 on the other hand, and / or connected accordingly, in order to circulate the heat transfer fluid 6 through the heat exchanger inlet line L by means of the heating pump 7. WT , zu to supply to the heat exchanger 4, in particular wherein the heat exchanger inlet line L WT , zu Partly already present and partly part of retrofit kit 1, in particular part of hydraulic module 21. A heat pump inlet line L WP, zu is fluidically connectable or connected to the heat exchanger 4 on the one hand and to the heat pump 11 on the other hand, and / or connected accordingly, in order to allow the heat transfer fluid 6 to flow through the heat pump supply line L WP, zu to supply to the heat pump 11, in particular wherein the heat pump supply line L WP, zuPartly already present and partly part of retrofit kit 1, in particular part of hydraulic module 21. A heat pump drain line L WP, ab is fluidically connected or connectable to the heat pump 11 on the one hand and to the primary heat source 3 on the other hand, and / or connected accordingly, in order to allow the heat transfer fluid 6 to flow through the heat pump drain line L WP, ab to supply the primary heat source 3, in particular wherein the heat pump drain line L WP, ab partly already present and partly part of the retrofit kit 1, in particular part of the hydraulic module 21.

[0103] In simplified terms, retrofit kit 1 includes at least the necessary pipes and / or hoses by means of which the desired flow connections between the components of retrofit kit 1 and the existing central heating system 2 can be created or implemented. In particular, retrofit kit 1 includes the aforementioned hydraulic module 21 for this purpose.

[0104] The primary heat source 3 preferably includes a distribution system (in Fig. 1a, Fig. 1c and Fig. (2 shown as a dashed line) for the heat transfer fluid 6, i.e., corresponding flow channels through which the heat transfer fluid 6 can flow, are provided, to which the heating circuits are each connected. The heat exchanger inlet line L WP, zu and the heat pump drain line L WP, abA pipe leading to the domestic hot water storage tank 5 and a pipe returning from the domestic hot water storage tank 5, each carrying the heat transfer fluid 6, are connected to the primary heat source 3, in particular to such a distribution system, or are fluidically connected to the primary heat source 3, in particular a boiler. The primary heat source 3, in particular the distribution system, can therefore be flowed through by the heat transfer fluid 6, so that the heat transfer fluid 6 may also be heated by the primary heat source 3 during this flow. However, the primary heat source 3, in particular the distribution system, can also be flowed through by the heat transfer fluid 6 without the heat transfer fluid 6 being heated by the primary heat source 3 during this flow, in particular without the primary heat source 3 being actively operated.

[0105] The retrofit kit 1 has at least one valve 19, by means of which the heat transfer fluid 6 can be directed and / or guided either from the primary heat source 3 to the heat exchanger 4 or past the heat exchanger 4 to the heat pump 11.

[0106] Valve 19 is in the Fig. 1a to Fig. 2 is shown as a single valve 19 with dashed lines, since it can be used as an alternative to the combination of two 3 / 2-way valves 20.1, 20.2 described below.

[0107] As an alternative to the single valve 19, the retrofit kit 1 has two 3 / 2-way valves, each with three connections and two switching positions, namely a first one, in particular in the heat exchanger inlet line L WT , zu a 3 / 2-way valve 20.1 that can be arranged or arranged accordingly and / or interposed, and a second one, in particular in the heat pump supply line L WP, zuA 3 / 2-way valve 20.2 is arranged or arranged accordingly and / or interposed. The first 3 / 2-way valve 20.1 is fluidically connected to the primary heat source 3, the heat exchanger 4, and the second 3 / 2-way valve 20.2. The second 3 / 2-way valve is fluidically connected to the heat exchanger 4, the heat pump, and the first 3 / 2-way valve 20.1. When connected, the first 3 / 2-way valve 20.1 allows the flow of the heat transfer fluid 6 from the primary heat source 3 to the heat exchanger 4 or to the second 3 / 2-way valve 20.2. By means of the second 3 / 2-way valve 20.1, in the connected state, it is possible to select either a flow of the heat transfer fluid 6 from the heat exchanger 4 or from the first 3 / 2-way valve 20.1 to the heat pump 11.

[0108] These described flow paths, which can be implemented using the two 3 / 2-way valves 20.1, 20.2, can also be implemented using the single valve 19, in particular as a 4 / 2-way valve with four ports and two switching positions, wherein in the first switching position of the valve 19, with the retrofit kit installed - i.e., in the connected state - a flow of the heat transfer fluid 6 from the primary heat source 3 via the heat exchanger 4 to the heat pump 11 is enabled, and wherein in a second switching position of the valve 19, with the retrofit kit installed, a flow of the heat transfer fluid 6 from the primary heat source 3 past the heat exchanger 4 to the heat pump 11 is enabled.

[0109] The aforementioned valve 19, in particular the first and second 3 / 2-way valve 20.1 and 20.2 respectively, or a valve 19 designed as a 4 / 2-way valve as mentioned above, is also connected, in particular for control purposes, to the heat pump control and / or regulation device 14, which is indicated by a corresponding dashed line, in particular in Fig. 2 should be shown. Or, to put it another way, the respective switching positions of the previously mentioned valve 19 can be realized with the help of the heat pump control and / or regulation device 14.

[0110] From the group of elements / components, namely the heat exchanger inlet line L WT , zu at least in sections, the heat pump supply line L WP, zu at least in sections, the heat pump drain line L WP, abat least in sections, the circulation pump 12, the heat pump control and / or regulating device 14 and the valve 19, in particular the first 3 / 2-way valve 20.1 and the second 3 / 2-way valve 20.2, are at least two elements and / or components, in particular the heat exchanger inlet line L WT , zu section by section, the heat pump supply line L WP, zu section by section, the heat pump drain line L WP, ab section by section, the first 3 / 2-way valve 20.1 and the second 3 / 2-way valve 20.2, preferably all elements and / or components, and their respective associated connections are arranged and / or formed on a hydraulic module 21 forming a common assembly.

[0111] The heat pump control and / or regulation device 14 is designed according to the Fig. 1a and Fig. 1c is not connected to hydraulic module 21. According to Fig. 1b The heat pump control and / or regulation unit 14 is connected to or integrated into the hydraulic module 21. For clarity, the heat pump control and / or regulation unit 14 is shown in the Fig. 2 shown next to the hydraulic module 21, Fig. However, 2 represents the assembled state for all three embodiments according to the Fig. 1a to Fig. 1c represents, so that according to Fig. 2. It should be noted that the heat pump control and / or regulation device 14 could also be connected to the hydraulic module 21.

[0112] The central heating system 2 is typically located inside a building. The heat pump 11, in particular an air / water heat pump 11 designed as a compact unit, can be located either inside or outside the building. When located inside the building, the heat pump 11 is connected to the building's external environment via air vents after installation. The hydraulic module 21 is preferably designed to be mounted adjacent to the central heating system 2 inside the building, so that the flow paths can be particularly short and the components / elements connected to the hydraulic module 21 can be protected from the elements by the building.

[0113] The hydraulic module 21 includes, in particular, a frame 22 for connecting the hydraulic module 21 to a building wall and / or to the primary heat source 3. The frame 22 could, for example, be a welded construction. Alternatively, the frame 22 could be located on or mounted on the floor of the building.

[0114] The part of the heat exchanger inlet line L belonging to the retrofit kit 1 WT , zu It has a first connection 23.1 for supplying the heat transfer fluid 6 to the hydraulic module 21 and a second connection 23.2 for removing the heat transfer fluid 6 from the hydraulic module 21. The part of the heat pump supply line L belonging to the retrofit kit 1 WP, zuIt has a third connection 23.3 for supplying the heat transfer fluid 6 to the hydraulic module 21 and a fourth connection 23.4 for draining the heat transfer fluid 6 from the hydraulic module 21. The part of the heat pump drain line L belonging to the retrofit kit 1 WP, ab has a fifth connection 23.5 for supplying the heat transfer fluid 6 to the hydraulic module 21 and a sixth connection 23.6 for removing the heat transfer fluid 6 from the hydraulic module 21.

[0115] Connections 23.1 to 23.6 are arranged spatially on or within the hydraulic module 21 in such a way as to enable a particularly simple and quick connection to the corresponding pipe sections belonging to the central heating system 2. Furthermore, the spatial arrangement of connections 23.1 to 23.6 and the pipes is optimized, particularly with regard to achieving short flow paths with low flow resistance.

[0116] The following section describes in more detail a procedure for retrofitting an existing central heating system 2 using the retrofit kit 1 described above: The retrofit procedure is carried out to remove the component that is in Fig. 1a to Fig. 1c shows the separate state of retrofit kit 1 and central heating system 2, to which in Fig. 2 to achieve the assembled state of retrofit kit 1 and central heating system 2 as shown.

[0117] The first temperature sensor 13.1 is mounted and / or arranged in a lower area of ​​the domestic hot water storage tank 5 (when viewed vertically) or adjacent to this lower area of ​​the domestic hot water storage tank 5 (when viewed vertically).

[0118] The first temperature sensor 13.1 is mounted either with direct contact of the measuring range of the first temperature sensor 13.1 to the domestic hot water 9 or in or on a wall of the domestic hot water storage tank 5 or the domestic hot water supply line 18 - viewed vertically - at the lower area of ​​the domestic hot water storage tank 5.

[0119] The first temperature sensor 13.1 is connected to the heat pump control and / or regulation unit 14 for control, signal, and / or data transmission. Specifically, a cable from the first temperature sensor 13.1 is connected to the heat pump control and / or regulation unit 14 via a plug connector for control, signal, and / or data transmission. Alternatively, a wireless connection, e.g., via radio, especially Bluetooth, would also be conceivable and would then be configured accordingly.

[0120] If the heat pump 11 is part of the existing central heating system 2, the heat pump 11 is connected to the heat pump control and / or regulation unit 14. Or if the heat pump 11 is part of the retrofit kit 1, the heat pump 11 is connected to the heat pump control and / or regulation unit 14 or is already connected.

[0121] The storage pump 8 is connected to the heat pump control and / or regulation device 14 for control purposes.

[0122] The heating pump 7 is connected to the heat pump control and / or regulation device 14 for control purposes.

[0123] If valve 19 is provided, valve 19 is connected to the heat pump control and / or regulation device 14 for control purposes.

[0124] As an alternative to valve 19, the first 3 / 2-way valve 20.1 and the second 3 / 2-way valve 20.2 are each connected to the heat pump control and / or regulation device 14 for control purposes.

[0125] All these control-related connections are generated using a cable and / or wirelessly, especially via radio.

[0126] An outdoor temperature sensor 13.a is mounted in an outdoor area, wherein the outdoor temperature sensor 13.a is or will be connected to the heat pump control and / or regulation device 14 in terms of control / signal / and / or data technology.

[0127] The outdoor temperature sensor 13.a is specifically adapted to the heat pump control and / or regulation device 14, so that a correct determination of the outdoor temperature in the external environment of a building is then possible.

[0128] The first limiting temperature T B1G or a table and / or a formula for determining the first limiting temperature T B1G The second limit temperature T is entered into the heat pump control and / or regulation unit 14 and / or is already stored there. B2G or a table and / or a formula for determining the second limit temperature T B2GThe value is entered into the central heating control and / or regulation unit 10 and / or is already stored there. When using the formula, it is particularly conceivable that certain parameters may also be entered for this formula.

[0129] The limiting temperature T B1G or the table and / or the formula for determining the first limit temperature T B1G The value is entered, for example, on a control panel of the heat pump control and / or regulation unit 14. Alternatively, it would be conceivable to connect an input unit, preferably a computer, to the heat pump control and / or regulation unit 14 and to perform the input using this input unit. The same applies analogously to the second limit temperature T. B2Gand the central heating control and / or regulation unit 10. In the highly preferred embodiment, however, the heat pump and / or regulation unit 14 is designed as a computer and / or has a corresponding microprocessor for carrying out the respective calculations and / or desired control sequences. Similarly, the central heating control and / or regulation unit 10 can also be designed as a computer or have a microprocessor.

[0130] It is conceivable that another outdoor temperature sensor is connected to the central heating control and / or regulation unit 10 in terms of control, signaling, and / or data transmission, so that the outdoor temperature T a can also be determined by means of this additional outdoor temperature sensor and the central heating control and / or regulation device 10.

[0131] Fig. 6a and Fig. Figure 6b shows a schematic representation of the first limiting temperature T. B1Gand the second limiting temperature T B2G with reference to the outside temperature T a how these are entered or stored, for example, in tabular form or as a formula, in the heat pump control and / or regulation unit 14 or the central heating control and / or regulation unit 10. In particular, the Fig. 6a and Fig. 6b also the settings of the first and second target heat transfer fluid temperatures T W1 , Soll or T W2 , Soll depending on a corresponding outside temperature T a .

[0132] The first and second limiting temperatures T B1G , T B2G are according to Fig. 6a and Fig. 6b as horizontal lines parallel to the x-axis of the outside temperature T a shown. The first and second limiting temperatures T B1G , T B2Gare therefore present in particular as constant values ​​in the heat pump control and / or regulating device 14 or in the central heating control and / or regulating device 10, so that the first and the second limit temperature T B1G , T B2G For the sake of simplicity, regardless of the outside temperature T a are.

[0133] Regarding the setting / initiation of the target heat transfer fluid temperature T W1 , Soll or T W2 , Soll and the respective first and second limit temperatures T B1G or T B2G Reference may be made to the previously stated explanations. However, it may be added here that a temperature difference between the first target heat transfer fluid temperature T W1 , Soll and the second target heat transfer fluid temperature T W2 , Soll preferably 7°C to 9°C, particularly 8°C with T W2 , Soll < T W1 ,Soll is. Put another way, the second target heat transfer fluid temperature T W2 , Soll In particular, it is set to a value 7°C to 9°C lower than the first target heat transfer fluid temperature T. W1 , Soll The second limiting temperature T B2G is in particular smaller than the second target heat transfer fluid temperature T W2 , Soll , preferably at least 2°C to 5°C lower, preferably 3°C to 4°C lower. In this way, in particular, effective heating of the domestic hot water 9 can also be achieved using the primary heat source 3.

[0134] The part of the heat exchanger inlet line L belonging to the retrofit kit 1 WT , zu is connected to the existing part of the heat exchanger inlet line L via the first and second connections 23.1, 23.2 WT , zu connected. The part of the heat pump supply line L belonging to retrofit kit 1. WP, zuThe third and fourth connections 23.3, 23.4 are connected to the existing part of the heat pump supply line L. WP, zu connected. The part of the heat pump drain line L belonging to retrofit kit 1. WP, ab is connected to the existing part of the heat pump drain line L by means of the fifth and sixth connections 23.5, 23.6 WP, ab connected. This can be done easily using the appropriately designed hydraulic module 21.

[0135] After connecting / using the retrofit kit 1, all desired fluid-related and / or control-related connections are realized, and the correspondingly retrofitted central heating system 2 can then be easily controlled and / or operated, in particular as described above, with the advantages explained above. Reference symbol list 1 Retrofit kit 2 Central heating system 3 Primary heat source 4 heat exchangers 5 domestic hot water storage tanks 6 Heat transfer fluid 7 Heating pump 8 Storage pump 9 Domestic water 10 Central heating control and / or regulation device 11 Heat pump 12 Circulation pump 13.1 First temperature sensor 13.2 second temperature sensor 13.a Outdoor temperature sensor 14 Heat pump control and / or regulation device 15 T-piece 16 Inlet valve 16.r Check valve 17 Inlet connection 18 Domestic hot water supply line 19 valve 20.1 first 3 / 2-way valve 20.2 second 3 / 2-way valve 21 Hydraulic module 22 frame 23.1 first connection 23.2 second connection 23.3 third connection 23.4 fourth connection 23.5 fifth connection 23.6 sixth connection T B1 first actual domestic hot water temperature T B2 second actual domestic hot water temperature T B1G first limit temperature T B1G' first switch-off limit temperature T B2G second limit temperature T B2G' second cut-off limit temperature T a Outside temperature T W1 first actual heat transfer fluid temperature T W2 second actual heat transfer fluid temperature T W1 , Soll first target heat transfer fluid temperature T W2 , Soll second target heat transfer fluid temperature L WT , zu Heat exchanger inlet line L WP, zu Heat pump inlet pipe L WP, ab Heat pump drain pipe V WP1 Operating and / or activating the heat pump 3 V WP2Deactivating the heat pump 3 V PR1 Operating and / or activating the primary heat source 2 V PR2 Deactivating primary heat source 2

Claims

[1] Retrofit kit (1) for an existing central heating system (2), wherein the central heating system (2) has at least one primary heat source (3) operable with the aid of fuels, in particular a boiler and / or a gas boiler, at least one heat exchanger (4), preferably a heating element or a radiator for heating a building, and at least one domestic hot water storage tank (5), wherein a heat transfer fluid (6), in particular water, can be heated by means of the primary heat source (3), wherein the heat transfer fluid (6) can be conveyed to and / or through the heat exchanger (4) by means of a heating pump (7), wherein the heat transfer fluid (6) can be conveyed to the domestic hot water storage tank (5) by means of a storage pump (8) for heating domestic hot water (9) temporarily stored in the domestic hot water storage tank (5), namely for heat transfer from the heat transfer fluid (6) to the domestic hot water (9) through or adjacent to the domestic hot water storage tank (5),wherein the primary heat source (3) has a central heating control and / or regulation device (10) for its control and / or regulation, wherein the retrofit kit (1) and / or the central heating system (2) has at least one electrically operated heat pump (11), wherein the heat transfer fluid (6) can be heated by means of the heat pump (11), wherein the heat transfer fluid (6) can be conveyed to and / or through the heat pump (11) for its heating, and wherein the heat transfer fluid (6) can be conveyed to and / or through the primary heat source (3) by means of the heating pump (7) and / or the storage pump (8), characterized bythat the retrofit kit (1) has a temperature sensor (13.1) and a separate heat pump control and / or regulation device (14) for the heat pump (11), wherein the temperature sensor (13.1) is or can be connected to the separate heat pump control and / or regulation device (14) in terms of control, signal, and / or data technology, wherein the heat pump (11) is and / or can be connected to the separate heat pump control and / or regulation device (14) in terms of control, wherein the separate heat pump control and / or regulation device (14) is designed and / or constructed such that the heat pump (11) is controlled in dependence on an actual domestic water temperature (T B1) is controllable and / or adjustable, wherein the temperature sensor (13.1) is used as a first temperature sensor (13.1) for determining a first actual domestic water temperature (T B1 ), wherein a second temperature sensor (13.2) is arranged in a vertically viewed middle or upper area of the domestic hot water storage tank (5) for measuring and / or determining a second actual domestic hot water temperature (T B2 ), wherein the second temperature sensor (13.2) is connected to the central heating control and / or regulation device (10) in terms of control, signaling and / or data technology, wherein the central heating control and / or regulation device (10) is designed and / or constructed such that the primary heat source (3) is controlled as a function of the second actual domestic water temperature (T B2) is controllable and / or regulatable, wherein the separate heat pump control and / or regulating device (14) is designed and / or constructed such that the heat pump (11) can be operated and / or activated with the aid of the separate heat pump control and / or regulating device (14) to heat the heat transfer fluid (6) when the first actual domestic water temperature (T B1 ) a first limit temperature (T B1G ) falls below. [2] Retrofit kit (1) according to claim 1, characterized by that the temperature sensor (13.1) can be mounted using a T-piece (15). [3] Retrofit kit according to claim 1, characterized by that the temperature sensor (13.1) can be arranged on the wall of the domestic hot water storage tank (5) in the vertically lower area of the domestic hot water storage tank (5). [4] Retrofit kit (1) according to one of claims 1 to 3, characterized bythat the central heating control and / or regulating device (10) is designed and / or constructed in such a way that the primary heat source (3) can be operated and / or activated with the aid of the central heating control and / or regulating device (10) to heat the heat transfer fluid (6) when the second actual domestic water temperature (T B2 ) a second limit temperature (T B2G ) falls below. [5] Retrofit kit according to claim 4, characterized by that the first and second limit temperatures (T B1G , T B2G) are selected such that the primary heat source (3) can only be operated and / or activated with the aid of the central heating control and / or regulating device (10) for heating the heat transfer fluid (6) when a heat requirement of the domestic hot water storage tank (5) exceeds a heat quantity that can be provided by means of the heat pump (11) at maximum output of the heat pump (11). [6] Retrofit kit (1) according to one of the preceding claims, characterized by that the heat exchanger (4) and the heat pump (11) are fluidically connected in series with respect to the primary heat source (3) and / or can be connected in series. [7] Retrofit kit (1) according to claim 6, characterized by that a heat exchanger inlet line (L WT , zu) is fluidically connectable and / or connected and / or connected accordingly to the primary heat source (3) on the one hand and to the heat exchanger (4) on the other hand, in order to convey the heat transfer fluid (6) by means of the heating pump (7) through the heat exchanger inlet line (L WT , zu ) to the heat exchanger (4), wherein a heat pump inlet line (L WP, zu ) is fluidically connectable and / or connected and / or connected accordingly to the heat exchanger (4) on the one hand and to the heat pump (11) on the other hand, in order to convey the heat transfer fluid (6) through the heat pump inlet line (L WP, zu ) to the heat pump (11), whereby a heat pump discharge line (L WP, ab ) is fluidically connectable and / or connected and / or connected accordingly to the heat pump (11) on the one hand and to the primary heat source (3) on the other hand, in order to convey the heat transfer fluid (6) through the heat pump discharge line (L WP, ab) to the primary heat source (3). [8] Retrofit kit (1) according to claim 7, characterized by that the retrofit kit (1) has at least one valve (19) by means of which the heat transfer fluid (6) can be directed and / or guided optionally from the primary heat source (3) to the heat exchanger (4) or past the heat exchanger (4) to the heat pump (11). [9] Retrofit kit (1) according to claim 7 or 8, characterized bythat the retrofit kit (1) has two 3 / 2-way valves, each with three connections and each with two switching positions, namely a first 3 / 2-way valve (20.1) and a second 3 / 2-way valve (20.2), wherein the first 3 / 2-way valve (20.1) is fluidically connectable and / or connected and / or correspondingly connected to the primary heat source (3), to the heat exchanger (4) and to the second 3 / 2-way valve (20.2), wherein the second 3 / 2-way valve is fluidically connectable and / or connected and / or correspondingly connected to the heat exchanger (4), to the heat pump (11) and to the first 3 / 2-way valve (20.1), wherein by means of the first 3 / 2-way valve (20.1) in the connected state, a flow of the heat transfer fluid (6) from the primary heat source (3) to the heat exchanger (4) or to the second 3 / 2-way valve (20.2), and wherein by means of the second 3 / 2-way valve (20.1) when connected, a flow of the heat transfer fluid (6) from the heat exchanger (4) or from the first 3 / 2-way valve (20.1) to the heat pump (11) is possible. [10] Retrofit kit (1) according to claim 9, characterized by that from the group of elements / components, namely the heat exchanger inflow line (L WT , zu ) at least in sections, of the heat pump inlet line (L WP, zu ) at least in sections, the heat pump drain line (L WP, ab ) at least in sections, a circulation pump (12), the separate heat pump control and / or regulating device (14) and the valve (19), at least two elements and / or components and respective associated connections are arranged and / or formed on a hydraulic module (21) forming a common structural unit. [11] Retrofit kit (1) according to claim 10, characterized by that the heat exchanger inlet line (L WT , zu) in sections, the heat pump inlet line (L WP, zu ) in sections, the heat pump drain line (L WP, ab ) in sections, the first 3 / 2-way valve (20.1) and the second 3 / 2-way valve (20.2) and respective associated connections are arranged and / or formed on the hydraulic module (21) forming a common structural unit. [12] Retrofit kit (1) according to claim 10 or 11, characterized by that the hydraulic module (21) has a frame (22) for fastening and / or arranging the hydraulic module (21) with a building wall and / or the primary heat source (3). [13] Retrofit kit (1) according to claim 10, 11 or 12, characterized by that the part of the heat exchanger inlet line (L WT , zu) has a first connection (23.1) for supplying the heat transfer fluid (6) to the hydraulic module (21) and a second connection (23.2) for discharging the heat transfer fluid (6) from the hydraulic module (21), wherein the part of the heat pump inflow line (L WP, zu ) has a third connection (23.3) for supplying the heat transfer fluid (6) to the hydraulic module (21) and a fourth connection (23.4) for discharging the heat transfer fluid (6) from the hydraulic module (21), wherein the part of the heat pump discharge line (L WP, ab ) has a fifth connection (23.5) for supplying the heat transfer fluid (6) to the hydraulic module (21) and a sixth connection (23.6) for discharging the heat transfer fluid (6) from the hydraulic module (21). [14] Method for retrofitting an existing central heating system (2) by means of a retrofit kit (1) according to one of the preceding claims, characterized bythat the first temperature sensor (13.1) is mounted and / or arranged in a vertically viewed lower area of the domestic hot water storage tank (5) or adjacent to this vertically viewed lower area of the domestic hot water storage tank (5). [15] Method according to claim 14, characterized by that the first temperature sensor (13.1) is connected to the separate heat pump control and / or regulation device (14) for control / signal / and / or data purposes. [16] Method according to claim 14 or 15, characterized bythat, in the event that the heat pump (11) is part of the already existing central heating system (2), the heat pump (11) is connected in terms of control technology (14) to the separate heat pump control and / or regulating device, or wherein, in the event that the heat pump (11) is part of the retrofit kit (1), the heat pump (11) is already connected or will be connected in terms of control technology to the separate heat pump control and / or regulating device (14). [17] Method according to one of claims 14 to 16, characterized by that the storage pump (8) is connected to the separate heat pump control and / or regulation device (14) for control purposes. [18] Method according to one of claims 14 to 17, characterized by that the heating pump (7) is connected to the separate heat pump control and / or regulation device (14) for control purposes. [19] Method according to one of claims 14 to 18, characterized bythat the valve (19) is connected to the separate heat pump control and / or regulation device (14) for control purposes. [20] Method according to one of claims 14 to 19, characterized by that the first 3 / 2-way valve (20.1) and the second 3 / 2-way valve (20.2) are each connected for control purposes to the separate heat pump control and / or regulation device (14). [21] Method according to one of claims 14 to 20, characterized by that an outside temperature sensor (13.a) is mounted in an outside area, wherein the outside temperature sensor (13.a) is or will be connected to the separate heat pump control and / or regulation device (14) in terms of control, signal and / or data technology. [22] Method according to one of claims 14 to 21, characterized by that the first limit temperature (T B1G ) or a table or a formula for determining the first limit temperature (T B1G) is input into the separate heat pump control and / or regulation device (14) or is already stored there, wherein the second limit temperature (T B2G ) or a table or a formula for determining the second limit temperature (T B2G ) is entered into the central heating control and / or regulation device (10) or is already stored there. [23] Method according to one of claims 14 to 22, characterized by that the part of the heat exchanger inlet line (L WT , zu ) by means of the first and second connection (23.1, 23.2) to the already existing part of the heat exchanger inlet line (L WT , zu ), whereby the part of the heat pump inlet line (L WP, zu ) by means of the third and fourth connection (23.3, 23.4) to the existing part of the heat pump inlet line (L WP, zu), whereby the part of the heat pump drain line (L WP, ab ) by means of the fifth and sixth connection (23.5, 23.6) to the existing part of the heat pump drain line (L WP, ab ) is connected. [24] Method according to one of claims 14 to 23, characterized by that the hydraulic module (21) is connected to the existing central heating system (2) for its retrofitting.

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