Method for retrofitting an old heating system, method for operating a heat pump system, heat pump system and computer program product

Abstract

A method is proposed for converting an old heating system with a gas boiler, a heating circuit (7) with consumers (5) having valves, such as radiators or underfloor heating, and an old hot water preparation system into a heat pump system (1) in a residential unit (2), comprising at least the following steps: a) Installing a heat pump (4) on an exterior wall (3) of the residential unit (2) and connecting it to a flow (14) and a return (15) of the heating circuit (7) of the old heating system, b) Installing a new hot water preparation system (8) at or in the immediate vicinity of a position (9) of the gas boiler of the old heating system and connecting the new hot water preparation system (8) to a cold water inlet (11) and a hot water outlet (10) and to the flow (14) and the return (15) of the heating circuit (7) of the old heating system,and c) Replacing the valves and / or control elements of the consumer valves (5) of the old heating system with wirelessly controllable valves (6) and / or with wirelessly controllable control elements of the valves. In addition, a heat pump system (1), a method for operating it, a computer program product (18) and a use are proposed.

Description

[0001] The invention relates to a method for converting an old heating system, a method for operating a heat pump system, a heat pump system and a computer program product.

[0002] The present invention relates in particular to heating systems for residential units in multi-family dwellings, which include separate existing heating systems assigned to the residential unit, in particular with a gas heating appliance, for example a wall-mounted gas boiler for heating and domestic hot water preparation. These are to be improved with regard to CO2 emissions.

[0003] The existing gas boiler produces CO2 emissions when burning gas to heat the house and, if applicable, also to supply hot water via an existing water heater. Given global warming and the growing collective awareness of the need for ecological change, there is a desire to switch to a renewable energy supply in order to reduce CO2 emissions and potentially even operating costs.

[0004] It is known to combine a heat pump with a gas boiler; such a system is presented, for example, in DE 3 024 714 A1. Although such a combined application is associated with high energy efficiency, implementation in residential units is often not possible due to lack of installation space.

[0005] German patent DE 10 2022 127 741 A1 also describes such a combination, namely a retrofit kit for an existing central heating system and a method for retrofitting an existing central heating system. The central heating system includes a domestic hot water storage tank. The retrofit kit includes a heat pump, a heat pump control and / or regulation unit, a heat exchanger, a temperature sensor to be installed in the domestic hot water storage tank, and several valves. The heat pump is installed in series with the existing primary heat source. As mentioned above, the necessary installation space is often not available in residential units.

[0006] According to current technology, converting an old heating system to a heat pump system requires considerable effort. The existing infrastructure of the old heating system must be dismantled and replaced with new equipment. This infrastructure primarily includes the pipes for the heating circuit and hot water supply. For example, an old heating system, or rather its pipe layout, does not allow for the installation of a hot water storage tank. A hot water storage tank is necessary for hot water supply via a heat pump system, as a heat pump cannot directly provide sufficient quantities of hot water. In contrast, an old gas heating system can switch to hot water operation and supply the required hot water flow rate directly from the heat generator.

[0007] It is therefore an object of the invention to at least partially alleviate or solve the problems described with reference to the prior art. In particular, a concept for retrofitting an existing heating system is to be presented that is simple and space-saving to implement. Specifically, the invention aims to enable the continued use of the existing heating system's pipes to a large extent. This applies to pipes of a heating circuit as well as pipes for the existing domestic hot water supply. Furthermore, it is desirable that the heat pump system can operate for the user without significant loss of comfort but with reduced CO2 emissions compared to the existing heating system.

[0008] These problems are solved by the features of the independent claims. Further advantageous embodiments of the solution proposed here are specified in the independent claims. It should be noted that the features listed in the dependent claims can be combined with one another in any technologically meaningful way and define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, which also presents further preferred embodiments of the invention.

[0009] This includes a method for converting an old heating system with a gas boiler (to be removed) to a heat pump system in a residential unit. The old heating system comprises a heating circuit with consumers such as radiators or underfloor heating systems that have valves, as well as an existing hot water preparation system. The method includes at least the following steps: a) Installing a heat pump on an exterior wall of the residential unit and connecting it to a flow and return line of the heating circuit of the old heating system, b) Installing a new hot water preparation system comprising a hot water storage tank at or in the immediate vicinity of the gas boiler of the old heating system and connecting the new hot water preparation system to a cold water inlet and a hot water outlet and the flow and return lines of the heating circuit of the old heating system, and c) Replacing the valves or control elements of the consumers of the old heating system with wirelessly controllable valves and / or control elements.

[0010] This process can be carried out once as part of a conversion / refurbishment of an existing heating system. Steps a), b), and c) can be performed once, in any order. This process is designed for a particularly simple conversion of an existing heating system for heating and hot water supply to a heat pump system.

[0011] The existing heating system can be installed in a building, particularly in a residential unit of an apartment building. This system is designed to heat the building's fixtures and fittings, ensuring a desired room temperature. These fixtures can be radiators, underfloor heating systems, or similar devices. They are characterized by their ability to transfer heat to the room or room surfaces, which is supplied via a heat transfer fluid circulating in a heating circuit. After the heat is released from the radiators, the heat transfer fluid is fed to a heat exchanger within the existing heating system. There, a fuel gas-air mixture is combusted, and the heat generated during combustion is transferred back to the heat transfer fluid.The old heating system may include pipes from an old hot water preparation system that supply drinking or service water heated by the old heating appliance to draw-off points such as taps, showers or bathtubs.

[0012] In a conventional gas-fired heating appliance, a fossil, gaseous fuel is typically burned with air to generate the desired heat. The exhaust gases, possibly after aftertreatment, are released into the environment via a flue system. Gas-fired heating appliances in residential units are often wall-mounted. The procedure proposed here can be implemented with both wall-mounted and floor-standing conventional heating appliances.

[0013] This method is particularly applicable to older heating systems where the heat transfer fluid is currently heated solely by a single gas-fired boiler. This means, in particular, that the gas-fired boiler is the only device in the heating system that (in a controlled manner) raises the temperature of the heat transfer fluid in the heating circuit. Furthermore, the older boiler is configured to provide hot water and is connected to a cold water inlet and a hot water outlet for this purpose. The cold water inlet can be connected, for example, to a supply network or a well / well pump, and the hot water outlet can supply the hot water heated by the older boiler to points of use such as shower, bathtub, or sink faucets. The older boiler is installed in a location that is generally in close proximity to the building's exhaust system and where a fuel gas supply is available.This installation position is generally not on or in the immediate vicinity of an exterior wall. In this context, an exterior wall refers to a wall of the dwelling unit that separates it from the outside environment. The following pipes may therefore be located at the installation position of the old heating unit: the flow and return pipes of the heating circuit, the cold water inlet, and the hot water outlet. In addition, an electrical power supply or a corresponding wiring connection is usually also present.

[0014] In principle, converting such an old heating system is a viable option, as reduced use / operation of the gas boiler results in lower CO2 emissions. For this purpose, a heat pump is installed or integrated to heat the heat transfer fluid in the heating circuit, and the old boiler is removed.

[0015] If a heat pump is to be installed in the heating system described above, a (new) hot water storage tank, i.e., a storage container for heated domestic hot water, should be installed at the same time. This allows heated domestic hot water to be stored for later use. For example, a user can then draw hot water for a shower or a bath without having to interrupt the heating operation of the heat pump.

[0016] The hot water storage tank can have a capacity of 50 to 100 liters, particularly 70 to 80 liters, and serves the heat pump system primarily for hot water supply. Typically, a residential unit only has one shower or bathtub, making the use of large quantities of hot water unlikely. For larger residential units, the storage capacity of the hot water storage tank can be adjusted. The hot water storage tank, or the new hot water system, can be designed as a wall-mounted unit, allowing it to be connected to the existing connections of the old heating system without any modifications. Alternatively, the hot water storage tank can also be a floor-standing unit, which is advantageous if the old heating system was also floor-standing.

[0017] A wirelessly controlled valve or charge valve is a valve where an opening or closing process can be initiated by means of a (wirelessly transmitted) radio signal. For this purpose, the valve can include an electrically operated actuator, such as a stepper motor. The use of wirelessly controlled valves or wirelessly controlled control elements for valves or charge valves advantageously enables a particularly simple conversion of a heating circuit for a heat pump as the heat generator, as it eliminates the need for complex work involving the installation of electrical cables to each consumer. A control element here refers to the actuation of the valve, specifically a device for regulating the motorized operation or drive of the valve, which can be addressed wirelessly and thus activated, adjusted, and / or deactivated.In other words, a predetermined valve opening width can be specified wirelessly and adjusted by motor.

[0018] According to step a), a heat pump can be installed on or in the immediate vicinity of an exterior wall of the residential unit and connected to an (existing) flow and a (existing) return of the heating circuit of the old heating system.

[0019] Depending on its design, the heat pump can be a monoblock unit. This typically includes a refrigeration circuit in which a refrigerant circulates, an evaporator connected to the refrigeration circuit in which the refrigerant evaporates and extracts heat from the surrounding medium (in this case, ambient air), and a condenser within the refrigeration circuit. This condenser converts the gaseous refrigerant into a liquid phase and transfers the resulting heat flow to the heating circuit's heat exchanger. An expansion valve and a compressor can also be positioned opposite each other between the evaporator and condenser to establish the pressures suitable for the refrigerant's phase change. The heat pump may also include a control unit for regulating and controlling its operation.All the aforementioned components of the heat pump can be arranged in a single housing, which is why the heat pump can be described as a monobloc heat pump. The heat pump can circulate a refrigerant with a low GWP (global warming potential) value, for example, R290 (propane). Heat pumps often also allow for a reverse cycle, in which the evaporator and condenser exchange functions, thus enabling heat removal and consequently cooling of the heat transfer fluid and thus the living space. Such a reverse cycle can be advantageously implemented with the heat pump system after carrying out the conversion procedure proposed here.

[0020] As part of step a), the heat pump can be installed on or near an exterior wall of the dwelling unit. This allows the heat pump access to ambient air as the exchange medium. For this purpose, the heat pump can have an inlet and an outlet for ambient air, between which the evaporator or the condenser can be located.

[0021] According to one embodiment, step a) involves creating a wall penetration through the exterior wall on or in the immediate vicinity of which the heat pump is installed. A wall penetration here refers to creating at least one opening in the exterior wall through which an air supply duct and an exhaust duct are routed to supply the heat pump with ambient air. In other words, the wall penetration provides the heat pump with access to ambient air as its primary energy source. It is advantageous if the heat pump is located directly on an exterior wall of the dwelling. The penetration can then be conveniently concealed by the heat pump's casing. Alternatively, the heat pump can also be installed in a location near an exterior wall. In this case, an air supply duct and an exhaust duct can run from the wall penetration to the heat pump.

[0022] According to step b), installing a new hot water system can involve installing a hot water storage tank at or in the immediate vicinity of the old boiler of the existing heating system and connecting the new hot water system to a cold water inlet and a hot water outlet, as well as to the flow and return of the heating circuit of the existing heating system. For clarity, the cold water inlet and hot water outlet, as well as the flow and return of the heating circuit, are connections of the old boiler to the existing heating system, so these are advantageously already present. The new hot water system includes a heat exchanger, which can be located, in particular, inside the hot water storage tank and enables the transfer of heat from the heat transfer medium of the heating circuit to the hot water contained in the hot water storage tank.

[0023] In particular, the new hot water preparation system can include a wirelessly controlled charging valve that can fully or partially open or close the supply of heat transfer fluid to the new hot water preparation system, i.e., the supply of heat transfer fluid to the heat exchanger in the hot water storage tank. Specifically, the wirelessly controlled charging valve can be located in a supply line of the new hot water preparation system.

[0024] According to step c), the valves and / or the control elements of the valves in the existing heating system can be replaced with wirelessly controlled valves and / or wirelessly controlled valve control elements. This can particularly involve (manually operated) thermostatic valves being replaced by wirelessly controlled thermostatic valves. The replacement enables control of the heat transfer fluid flow rates in the heating circuit. It is particularly possible that only the control element or the valve itself is replaced, while the valve itself continues to be used. It is preferred, however, that all valves in the existing heating system, or their control elements, are replaced.

[0025] A control and regulating device, in particular the control and regulating device of the heat pump, can be configured to communicate with the wirelessly controllable valves of the consumers and the charging valve of the new hot water preparation and in particular to initiate an opening or closing process.

[0026] This process results in a heat pump system in which a heat pump is connected to the heating circuit and can heat the heat transfer fluid of that circuit. The domestic hot water system can then transfer the heated heat transfer fluid from the heating circuit to the domestic hot water or drinking water, thus providing heated domestic hot water or drinking water for use.

[0027] According to one embodiment, the heat pump system can include one or more temperature sensors used for regulation and control. These temperature sensors can also be wirelessly connected to the control unit. For example, a temperature sensor can measure the temperature of the potable or domestic hot water contained in the hot water storage tank and transmit this information to the control unit. Alternatively, a temperature sensor can be provided to detect the outside temperature. In particular, a temperature sensor for detecting the outside temperature can be located in an air intake of the heat pump. This can advantageously reduce the installation effort for the temperature sensor considerably, while simultaneously increasing measurement accuracy, since the actual temperature of the supplied air is measured in the air intake and is not influenced by solar radiation or other factors.

[0028] A further aspect is addressed in the proposed method for operating a heat pump system that has been retrofitted using the procedure suggested here. This method proposes that, when initiating a charging cycle of the hot water storage tank, the wirelessly controlled valves of the consumers should be largely or completely closed, and the charging valve in the supply line of the new hot water preparation should be opened.

[0029] This method can be implemented permanently or continuously, particularly during the operation of a heat pump system. It enables the efficient charging of a hot water storage tank in a heat pump system that has been retrofitted from an older heating system using the conversion method proposed here. Advantageously, by closing the wirelessly controlled valves (e.g., via their wireless control elements), the consumer can ensure that virtually all of the heat flow provided by the heat pump, or all of the heat transfer fluid circulating in the heating circuit and heated by the heat pump, is directed to the hot water storage tank and used to heat the domestic hot water or drinking water contained within.

[0030] According to one embodiment, when the wirelessly controlled valves of the consumers are almost completely closed, the wirelessly controlled valves of specific rooms can be left partially open. This advantageously prevents the residential unit, and especially specific rooms within the unit, from cooling down during the heating of the hot water storage tank. For example, a predetermined heat flow could be supplied to the initial hot water heating process, and any additional heat flow provided by the heat pump could be supplied to the consumers in specific rooms, such as a bathroom or living room, within the residential unit.

[0031] Another aspect proposed is a heat pump system that has been retrofitted from an existing heating system using a method suggested here. This system includes, in particular, a heat pump and a new domestic hot water system with a hot water storage tank, both connected to a heating circuit. The heat pump system also includes one or more consumers, such as radiators and / or underfloor heating, equipped with wirelessly controlled valves. These wirelessly controlled valves can be operated via a radio signal, thus eliminating the need for wiring. The new domestic hot water system also includes a charging valve, which can likewise be wirelessly controlled. The heat pump also includes a control unit, which can be configured to operate the heat pump system using a method suggested here.

[0032] In addition, a control unit for a heat pump is proposed, designed to carry out a procedure proposed here. This control unit may, for example, include a processor. In this context, the processor can execute the procedure stored in the control unit's memory. The control unit can wirelessly transmit signals to the wirelessly controlled valves of the consumers and / or to a charging valve for the domestic hot water system. Furthermore, data acquired or required during the execution of this proposed procedure can be stored in the control unit's memory.

[0033] In addition, a computer program is proposed, comprising commands that cause a computer, for example a control and monitoring device, to execute a procedure proposed here for operating a heat pump system.

[0034] Another aspect is the proposed use of wirelessly controllable valves (e.g. via their wirelessly operating control elements) of the consumers of a heating circuit connected to a heat pump system to reduce the flow rate of the heating circuit during a storage charging of a hot water storage tank of the heat pump system.

[0035] The details, features, and advantageous configurations discussed in connection with the processes may also occur in the heat pump system, computer program, control unit, and / or application presented here, and vice versa. In this respect, full reference is made to the explanations provided therein for a more detailed characterization of the features.

[0036] The invention and its technical context are explained in more detail below with reference to the accompanying figure. It should be noted that the invention is not limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts illustrated in the figure and combine them with other elements and findings from the present description. It should be emphasized that the figure, and especially the depicted dimensions, are only schematic. The figures show: Fig. 1 : a process outlined here for converting an old heating system, and Fig. 2 : a heat pump system proposed here.

[0037] Fig. 1 This diagram illustrates, schematically, the process of a proposed procedure for converting an existing heating system to a heat pump system. The procedure is designed for a particularly simple conversion, requiring little to no rerouting of fluid transport pipes or electrical wiring. The proposed procedure, including blocks 110, 120, and 130, can be performed once during the conversion of the existing heating system. The sequence of steps a), b), and c) shown in blocks 110, 120, and 130 can occur during normal operation, and the order in which the steps are performed is arbitrary and can even be carried out simultaneously.

[0038] Fig. 2 This shows, by way of example and schematically, a heat pump system 1 in a residential unit 2, which, according to a design proposed here and in Fig. 1 The described procedure involved the conversion of an existing heating system. Apartment unit 2 is part of an apartment building and, prior to the implementation of the proposed procedure, was equipped with an (old) gas boiler located at installation position 9, supplying only apartment unit 2. The existing heating system also included a heating circuit 7 with a flow 14 and a return 15, which is to be advantageously used by the heat pump system 1. Heating circuit 7 can contain consumers 5, such as radiators or underfloor heating.

[0039] In block 110, according to step a), a heat pump 4 can be installed on an exterior wall 3 of residential unit 2 and connected to the flow 14 and return 15 of the heating circuit 7 of the existing heating system. A wall penetration can be created through the exterior wall 3, through which the heat pump 4 can draw in outside air as a heat source.

[0040] In block 120, according to step b), a new hot water preparation unit 8 can be installed at or in the immediate vicinity of a position 9 of the gas boiler of the old heating system and connected to a cold water inlet 11 and a hot water outlet 10 (of the old heating system) and to the flow 14 and return 15 of the heating circuit 7 of the old heating system. The new hot water preparation unit 8 can include a hot water storage tank 13 in which a heat exchanger 17 is arranged, which is connected to the flow 14 and the return 15. The new hot water preparation unit 8 can have a wirelessly controllable charging valve 12, which is arranged in the flow 14 and can open and close the supply of heat transfer fluid to the new hot water preparation unit 8.

[0041] In block 130, according to step c), the valves of consumers 5 of the old heating system (and their control elements, if applicable) can be replaced with wirelessly controlled valves 6 (or their wirelessly operating control elements). This step is easy to carry out, as the old valves simply need to be removed from the designated valve mounting points on consumers 5 and wirelessly controlled valves 6 installed.

[0042] The heat pump 4 includes a control unit 16, which is configured to execute a method proposed here for operating the heat pump system 1. For this purpose, the control unit 16 can have a radio unit that can send radio signals to the wirelessly controllable valves 6 and the wirelessly controllable charging valve 12 and thus control them.

[0043] In one of the methods proposed here for operating the heat pump system 1, the wirelessly controllable valves 6 of the consumers 5 can be largely or completely closed and the charging valve 12 opened for charging the hot water storage tank 13. This allows the heat transfer fluid heated by the heat pump in the heating circuit 7 to be supplied almost completely to the heat exchanger 17, thus heating the hot water contained in the hot water storage tank 13. Charging the hot water storage tank 13 can be achieved, for example, by a [missing information - likely a specific device or component] in the Fig. 2 The temperature sensor (not shown), which detects the temperature of the hot water contained in the hot water storage tank 13, is triggered. The method for operating the heat pump system 1 can be executed by the control unit 16 in the form of a computer program 18, which is stored in a memory of the control unit 16. Reference symbol list

[0044] 1 Heat pump system 2 Residential unit 3 Exterior wall 4 Heat pump 5 Consumer 6 Wirelessly controllable valve 7 Heating circuit 8 New hot water preparation 9 Position 10 Hot water outlet 11 Cold water inlet 12 Charging valve 13 Hot water storage tank 14 Flow 15 Return 16 Control and monitoring unit 17 Heat exchanger 18 Computer program product

Claims

1. Method for converting an old heating system, comprising a gas boiler to be removed, a heating circuit (7) with consumers (5) having valves, and an old domestic hot water system, to a heat pump system (1) in a residential unit (2), comprising at least the following steps: a) Installing a heat pump (4) on an exterior wall (3) of the residential unit (2) and connecting the heat pump (4) to a flow (14) and a return (15) of the heating circuit (7) of the old heating system, b) Installing a new domestic hot water system (8) at or in the immediate vicinity of a position (9) of the gas boiler of the old heating system and connecting the new domestic hot water system (8) to a cold water inlet (11) and a hot water outlet (10) and to the flow (14) and the return (15) of the heating circuit (7) of the old heating system,and c) Replacing the valves and / or control elements of the consumer valves (5) of the old heating system with wirelessly controllable valves (6) and / or with wirelessly controllable control elements of the valves.

2. Method according to claim 1, wherein the heat pump (4) uses ambient air for heat extraction and, in the course of carrying out step a), a breakthrough is made through the outer wall (3) through which the heat pump (4) can draw in outside air.

3. Method according to one of the preceding claims, wherein the heat pump system (1) comprises a control and regulating device (16) which is configured to control the wirelessly controllable valves (6) replaced in step c).

4. Method for operating a heat pump system (1) which has been retrofitted by means of a method according to one of the preceding claims, wherein a storage charging of the hot water storage tank (13) can be initiated, in which the wirelessly controllable valves (6) of the consumers (5) are closed and a charging valve (12) in the flow line (14) of the new hot water preparation (8) is opened.

5. Method for operating a heat pump system (1) according to claim 4, wherein when the wirelessly controllable valves (6) of the consumers (7) are closed to the greatest extent, the wirelessly controllable valves (6) of predetermined rooms are not completely closed.

6. Heat pump system (1) which has been retrofitted with a method according to claim 1 and comprises a control and regulating device (16) and means for carrying out a method for operating a heat pump system (1) according to one of claims 4 or 5.

7. Heat pump system (1) according to claim 6, wherein the heat pump (4) is an air-to-water heat pump in monoblock design.

8. Heat pump system (1) according to claim 6 or 7, wherein the heat pump system (1) comprises a control and regulating device (16) which is configured to control the wirelessly controllable valves (6) and / or their control elements exchanged in step c).

9. Computer program product (18) comprising commands that cause a heat pump system (1) according to claim 6 to execute a method for operating a heat pump system (1) according to claim 4 or 5.

10. Use of wirelessly controllable valves (6) of the consumers (5) of a heating circuit (7) connected to a heat pump system (1) to reduce the flow rate of the heating circuit (7) during a storage charging of a hot water storage tank (13) of the heat pump system (1).

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