Device for generating heat

Abstract

Device for generating heat for the purpose of feeding it into a heating circuit (12), comprising - a high-pressure pump (2) connected in a liquid circuit, driven by a motor, in particular an electric motor, with an inlet (4) through which the liquid to be pumped enters the pump (2), and with an outlet (5) from which the pumped liquid exits, - at least one heat generator (6) connected in the liquid circuit, downstream of the pump (2), causing friction in the liquid flow by reducing the flow cross-section, wherein the heat transfer medium (6) has a cross-sectional geometry that is not influenced by the delivery pressure of the liquid flow, so that the temperature of the liquid flow conveyed by the at least one heat generator (6) is increased, - a liquid storage tank (10) integrated into the liquid circuit and to which at least one heat generator (6) is connected downstream in the direction of flow of the liquid, as well as - a heating circuit (12) connected to the liquid storage tank (10).

Description

[0001] The invention relates to a device for generating heat for feeding it into a heating circuit.

[0002] Such devices include heat pumps, for example. According to the heat pump principle, heat is extracted from a heat source, such as the ambient air (outside air) or another heat source, such as the ground or groundwater, and fed to an evaporator. The evaporator is part of a fluid circuit in which the heat extracted from the heat source evaporates the liquid in the circuit. This is typically a refrigerant. This gaseous phase is compressed in a compressor, which increases the temperature level of the gaseous fluid. In a second heat exchanger, this gas is liquefied by condensation, thereby releasing heat. This heat exchanger is integrated into a heating circuit, through which the extracted heat is distributed throughout a building. The liquefied refrigerant is then fed back to the evaporator via a throttle.Heat pumps are highly efficient for heating buildings. However, the flow temperature generated by a heat pump for a heating circuit is lower than that of conventional oil- or gas-fired heating systems, which do not operate panel radiators such as underfloor heating. Heating existing properties with heat pumps often requires not only extensive renovation work but also modifications to the existing heating system. In any case, the heat radiating surfaces must be significantly enlarged due to the lower flow temperature. It may be necessary to retrofit underfloor heating. The cost, especially financial, is considerable.

[0003] A device for mechanically heating a liquid is known from WO 2010 / 057491 A2. This device comprises a container with a circumferentially closed container wall, containing the liquid to be heated. Arranged within the container are one or more elements with openings and / or capillaries and / or pores through which the liquid flows and is heated by the resulting friction. For this purpose, one or more elements are set in rotation, so that the liquid is forced through the vane-like elements. While this principle allows heat to be generated, it is not sufficient to effectively use the generated heat for feeding it into a heating circuit.

[0004] US 3,813,036 discloses a heating system. This known heating system comprises a closed oil circuit. A pump pumps oil through a friction heating element, so that the temperature at the outlet of this friction heating element is higher than at the inlet. According to this known heating system, several such heating elements can also be arranged in parallel. One or more heat radiation units are connected downstream of the friction heating element(s) as heat generators. The generated heat is dissipated via these units. The outlet of the heat radiation unit(s) is connected to a collecting tank. The friction heating elements are woven metal wire, which is compressed and arranged in a cylinder block. A disadvantage of this known heating system is that the pump must be operated for the entire heating period.Another disadvantage is that the flow-through cross-sectional area of ​​the heat generator, because it is made of woven wire, changes depending on the applied pressure. The maximum operating pressure is specified as 137 bar. This heating system is a standalone system and cannot be combined with an existing heating system.

[0005] Against the background of the state of the art described above, it would therefore be desirable to have a device, in particular an electrically operated device, for generating heat for feeding it into a heating circuit, with which flow temperatures can also be generated which correspond to those of an otherwise conventional oil or gas heating system which supplies heat to radiators as heat-emitting elements.

[0006] The object of the invention is therefore to propose such a device.

[0007] This object is achieved by a device for generating heat for feeding it into a heating circuit, comprising - a high-pressure pump connected to a liquid circuit, driven by a motor, in particular an electric motor, with an inlet through which the liquid to be pumped enters the pump and with an outlet from which the pumped liquid emerges, - at least one heat generator connected to the liquid circuit, downstream of the pump, causing friction in the liquid flow by reducing the flow cross-section, wherein the heat generator has a cross-sectional geometry that cannot be influenced by the delivery pressure of the liquid flow, so that the temperature of the liquid flow conveyed by the at least one heat generator is increased, - a liquid storage device connected to the liquid circuit and connected downstream of at least one heat generator in the direction of flow of the liquid, and - a heating circuit connected to the liquid storage tank.

[0008] This heat generation device comprises a high-pressure pump, preferably driven by an electric motor. This pump is connected to a fluid circuit. The fluid flow emerging from the pump outlet impinges on at least one heat generator connected downstream of the pump. The fluid flow is conveyed through the heat generator. For the desired heat generation, the heat generator reduces the flow-through cross-sectional area, thus providing a corresponding counterpressure. The heat generator is designed like a hydraulic orifice plate with one or more openings. The sum of these openings then represents the free flow-through cross-sectional area.The heat generator thus introduces heat into the liquid flow conveyed by the at least one heat generator via the friction generated in the liquid flow conveyed by the heat generator, so that the temperature of the liquid flow conveyed by the pump through the heat generator is higher at its outlet than at its inlet. The heat generator counteracts the liquid flow conveyed by the high-pressure pump with a backpressure. The higher the backpressure from the heat generator, the greater the temperature difference that can be coupled into the liquid flow. A temperature difference that is sufficient in many cases can be generated at backpressures of more than 120 to 150 bar. High-pressure pumps that can overcome a backpressure of 200 bar or more are preferred. The backpressure provided by the heat generator will be designed accordingly.It is possible to design the heat generator with several such hydraulic orifices arranged in series in the direction of fluid flow, or to configure several individual heat generators in series. These can certainly be of different types.

[0009] Between one or the last heat generator in the direction of flow and the liquid storage tank there is an expansion section in which the pumped liquid expands to prevent it from flowing into the liquid storage tank under excessive pressure. The liquid storage tank is preferably thermally insulated so that the heat introduced into the liquid by the heat generator(s) can be stored there. Such a liquid storage tank could, for example, be the hot water tank (boiler) that is already present in a conventional oil or gas heating system. Connected to this is the heating circuit, which is fed by the liquid heated in the liquid storage tank. The heating circuit can be connected to the liquid storage tank independently of a heat generation circuit pumped by the pump.A circulation pump integrated into this heating circuit ensures the necessary fluid transport to the individual heat dissipation points. A possible configuration is one in which the return of the heating circuit is directly connected to the pump inlet. This also allows the heating circuit to be operated in series with the heat generation system.

[0010] In order to heat the contents of such a liquid reservoir back to the intended flow temperature after a corresponding drop in temperature without having to pump the liquid through the entire heating circuit, it is advantageous to provide a line that bypasses the heating circuit and connects the liquid reservoir directly to the pump inlet. A heat generation circuit is then provided via this heating circuit bypass line. When the pump is in operation, the contents of the liquid reservoir can then be circulated and heated to the desired temperature. The liquid reservoir is typically equipped with a temperature sensor to monitor the prevailing liquid temperature. Studies have shown that with such a heat generation device with a heat generator that provides a back pressure of around 200 bar, 30 l of water can be heated by 10°C in one minute.In a correspondingly short time, a liquid container of 80 l, which corresponds to the usual size of a conventional boiler, is heated up again to the desired temperature.

[0011] In a further development of such a heat generation device, it is provided to utilize not only the introduced temperature, but also the kinetic energy coupled into the liquid with the heating of the latter. The kinetic energy coupled into the liquid jet for heat generation, which the liquid conveyed through the at least one heat generator has, is not required for heating the liquid in the liquid reservoir. Therefore, in various embodiments, it is provided to utilize this kinetic energy and to connect an aggregate into the flow path between the heat generator and the liquid reservoir, which aggregate is driven by the liquid jet (liquid flow) emerging from the heat generator. Such an aggregate can be one that provides no or only a slight counterpressure.According to another embodiment of such a heat generation device, the unit driven by the fluid flow itself generates a significant backpressure. This is typically lower than the backpressure caused by the heat generator(s). In the first case, this can be, for example, a blade turbine arranged in a housing. In the second case, the unit can be designed, for example, as an axial piston pump. Both measures make it possible to harness the kinetic energy present in the fluid flow, for example, to drive a generator and thus recover energy, thereby improving the energy balance of the heat generation device.

[0012] In another such embodiment, the output of the heat generator is provided for the input of a hydraulic motor, whose output is connected to the fluid reservoir. The hydraulic motor driven by the high-pressure pump can be used to support the drive of the high-pressure pump by means of the electric motor. This also improves the energy balance of the heat generation device, since the hydraulic motor supports the torque of the electric motor, thus requiring less electrical energy to operate the heat generation device.

[0013] If such a unit downstream of the heat generator also provides significant backpressure, as is the case with an axial piston pump, for example, this also contributes to an increase in the temperature of the flowing fluid due to the friction acting on the fluid. In this respect, such a design of the heat generator can also be described as having a first heat generator and a second heat generator downstream of it.

[0014] If a unit generating back pressure is connected downstream of a heat generator, such as an axial piston engine, according to a preferred embodiment, the flow cross-section reduction through the heat generator is kept constant at least as far as possible up to the inlet of the downstream unit, thus no expansion path, at least no significant one, is provided between the heat generator and the unit generating a further back pressure.

[0015] In a preferred embodiment, the heat generator is part of a heat exchanger. In such a configuration, the heat generator is located in a heat exchanger housing, with fluid passage provided between the heat generator and the housing. The housing has a flow and a return connection and is integrated into a heat exchanger circuit. In this way, the heat radiated via the jacket surface of the heat generator can be utilized. This additional heat recovery can, as is the case in a preferred embodiment, also be used to heat the liquid in the liquid reservoir. A particularly effective measure for utilizing the heat radiated by the heat generator is to use the heat generator heat exchanger as a heat source for a heat pump.In such a case, a refrigerant is used as the heat exchanger fluid. It flows into the heat generator heat exchanger in liquid form via the return connection, evaporates due to the heat from the heat generator, and exits the flow connection in gaseous form. A compressor connected to the flow line compresses the gaseous refrigerant. A heat exchanger is connected downstream of this compressor, where the heat supplied by the refrigerant is extracted and transferred to the liquid storage tank. This heat exchanger is connected to the liquid storage tank via a corresponding liquid supply and return line.

[0016] Appropriate valves are provided in the heat generation circuit to control or switch the device. The same applies to the heating circuit connected to the liquid storage tank.

[0017] Preferably, water is used as the liquid in such a heat generation device, particularly if it is to be connected to an existing heating system. This can be easily heated to the desired or required flow temperature using the heat generation device described above. In an existing, particularly conventional, heating system, the water boiler can serve as a liquid storage tank. Water as the liquid for operating the heat generation device is also advantageous because water can absorb less gravitational force than oil, thus improving the temperature yield. The connection of the preferably electric motor-driven pump and the heat generator(s) to an existing oil or gas heating system is possible without major effort. In this respect, the heat generation device described above is particularly suitable for retrofitting an existing oil or gas heating system.Thus, an existing oil or gas heating system supplemented by a heat generation system can be operated primarily with green energy in a hybrid system. The advantages of such a heat generation system compared to retrofitting or installing heat pumps are the low acquisition costs and, above all, the integration into existing heating systems, thus making it cost-effective.

[0018] The invention is described below using exemplary embodiments. They show: Fig. 1: In the form of a schematic block diagram, a heat generating device according to the invention, Fig. 2: A heat generating device according to a further embodiment of the invention and Fig. 3: A heat generating device according to yet another embodiment of the invention.

[0019] The Fig. The heat generating device 1 shown in Figure 1 comprises a high-pressure pump 2. The high-pressure pump 2 is driven by an electric motor 3, which has a power consumption so that it can be connected to the 220 V mains.

[0020] The high-pressure pump 2 has an inlet 4. The liquid to be pumped enters this inlet. The liquid pumped by the pump 2 is pumped out of the pump 2 through an outlet 5. A heat generator 6 is connected to the outlet 5. The heat generator 6 counteracts the liquid flow pumped by the pump 2 with a back pressure. In the illustrated embodiment, this pressure is approximately 200 bar. The high-pressure pump 2 is therefore designed so that the liquid flow pumped by it can overcome this back pressure. This back pressure of the heat generator 6 is provided by a hydraulic orifice plate having a single opening. This significantly reduces the cross-sectional area through which the liquid can flow. This orifice plate induces turbulence and thus friction in the liquid flow pumped through it, which in turn causes an increase in the temperature of the liquid flow pumped by the heat generator.Thus, in the heat generating device 1, a liquid flow is heated by introducing kinetic energy and thus by friction.

[0021] In the illustrated embodiment, an axial piston pump 7 is connected downstream of the heat generator 6, which drives a generator 8. Between the heat generator 6 and the inlet of the axial piston pump 7, the fluid flow conveyed by the heat generator 6 is not expanded, or at least not significantly. The backpressure provided by the axial piston pump 7 is lower than the backpressure provided by the heat generator 6 to the fluid flow conveyed by the pump 2. The kinetic energy (motion energy) introduced into the fluid flow is used in this embodiment to drive the axial piston pump 7 and thus the generator 8. Since the axial piston motor 7 also opposes a backpressure to the incoming fluid flow, the fluid flow also experiences friction in the axial piston motor 7, which contributes to a further increase in its temperature.In this respect, in this embodiment of the heat generating device 1, the axial piston motor 7 can also be referred to as a heat generator.

[0022] The output of the axial piston pump 7 is connected to a fluid reservoir 10 via a line 9. In the illustrated embodiment, the line 9 serves as a pressure relief line for expanding the fluid flow conveyed therein. The fluid reservoir 10 is a boiler, which is also connected, in a manner not shown in detail, to a fossil fuel-fired burner (oil or gas burner). The capacity of the fluid reservoir 10 is, for example, 80 l.

[0023] In an embodiment not shown in the figures, the outlet of the heat generator 6 is directly connected to the liquid storage 10.

[0024] In a further development of the heat generating device 1 shown in the figure, a bypass line is inserted into the fluid path between the heat generator 6 and the fluid reservoir 10, via which bypass line the fluid flow can be introduced directly from the heat generator 6 into the fluid reservoir 10, bypassing the axial piston pump 7.

[0025] The liquid reservoir 10 is directly connected to the inlet 4 of the pump 2 via a bypass line 11. This provides a heat generation circuit through which the liquid contents in the liquid reservoir 10 can be heated by circulation.

[0026] The liquid storage tank 10 is connected to a heating circuit 12, the flow of which is identified in the figure by reference numeral 13 and the return of which is identified in the figure by reference numeral 14. One or more circulation pumps are used to pump the liquid in the heating circuit 12. The heating systems already present in the building (typically radiators) are typically connected to the heating circuit 12 for heat dissipation.

[0027] Fig. 2 shows a heat generating device 1.1 which is basically constructed like the one to Fig. 1 described heat generating device 1. Therefore, the statements regarding heat generating device 1 apply equally to heat generating device 1.1. Identical components are identified with the same reference numerals, supplemented by a ".1" in the figure. Heat generating device 1.1 differs from heat generating device 1 in that a hydraulic motor 15 is connected downstream of heat generator 6.1 before the liquid heated by heat generator 6.1 is fed to liquid reservoir 10.1. Hydraulic motor 15 is located on the drive shaft of electric motor 3.1 and thus supports the drive of high-pressure pump 2.1. This means that the torque provided by hydraulic motor 15 does not have to be provided by electric motor 3.1 to drive high-pressure pump 2.1, which is noticeable in a reduced power consumption of electric motor 3.1.

[0028] Fig. 3 shows a further heat generating device 1.2. This corresponds to heat generating device 1, which is why the relevant statements apply equally to heat generating device 1.2. Identical components are identified in the figure by the same reference numerals, supplemented by a ".2". Heat generating device 1.2 is ultimately a further development of heat generating device 1. Likewise, any other heat generating device according to the invention could also be supplemented by the further development explained below. In the further development of heat generating device 1 to form heat generating device 1.2, the heat radiated by heat generator 6.2 via its outer surface is utilized. Heat generator 6.2 is part of a heat exchanger, which is why this unit is also referred to below as heat generator heat exchanger 16. Heat generator 6.2, which, like the other exemplary embodiments, is constructed from three hydraulic orifices connected in series, for example, is located in a heat exchanger housing 17. The heat exchanger housing 17 has a return connection 18 and a flow connection 19. The fluid to be heated in the heat generator heat exchanger 16 is introduced via the return connection 18 into the fluid path between the housing 17 and the outer surface of the heat generator 6.2 and, when the heat generating device 1.2 is in operation, exits heated from the flow connection 19. The heat generator heat exchanger 16 is connected to a heat exchanger circuit. Fig.In the embodiment shown in Figure 3, the heat exchanger circuit is a heat pump circuit. A compressor 22 is connected to the supply line 20, which supplies a heat exchanger 21. The heat exchanger 21 is in turn connected to the return connection 18 of the heat generator heat exchanger 16 via a return line 23. The heat exchanger 21 itself has a condenser in the illustrated embodiment. A refrigerant commonly used for this purpose serves as the heat exchange fluid.

[0029] Heat exchanger 21 is connected to the liquid reservoir 10.2 via the flow line 20 and the return line 23. Thus, the liquid in the liquid reservoir 10.2 is heated not only by the liquid jet heated by the heat generator 6.2, but also by the heat generated by the heat pump. For this reason, the energy balance of the heat generator 1.2 is particularly favorable.

[0030] The invention has been described using exemplary embodiments. Without departing from the scope of protection described by the applicable claims, numerous further embodiments for implementing the inventive concept will become apparent to those skilled in the art without the need for further explanation within the scope of these statements. List of reference symbols 1, 1.2 Heat generation device 2, 2.1 High-pressure pump 3, 3.1 Electric motor 4 Inlet 5 Outlet 6, 6.1, 6.2 Heat generators 7 axial piston pump 8 Generator 9 Bypass line 10, 10.1, 10.2 Liquid storage 11 Bypass line 12 heating circuits 13 Lead-up 14 Return 15 Hydraulic motor 16 heat generator heat exchangers 17 housings 18 Return connection 19 Flow connection 20 flow line 21 heat exchangers 22 compressors 23 Return line QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2010 / 057491 A2

[0003] US 3,813,036

[0004]

Claims

[1] Device for generating heat for feeding it into a heating circuit (12), comprising - a high-pressure pump (2) connected to a liquid circuit and driven by a motor, in particular an electric motor, with an inlet (4) through which the liquid to be pumped enters the pump (2) and with an outlet (5) from which the pumped liquid emerges, - at least one heat generator (6) connected to the liquid circuit and downstream of the pump (2) and causing friction in the liquid flow by reducing the flow cross-section, wherein the heat carrier (6) has a cross-sectional geometry that cannot be influenced by the delivery pressure of the liquid flow, so that the temperature of the liquid flow conveyed by the at least one heat generator (6) is increased, - a liquid storage device (10) connected to the liquid circuit and connected downstream of the at least one heat generator (6) in the flow direction of the liquid, and - a heating circuit (12) connected to the liquid storage tank (10). [2] Device according to claim 1, characterized by that the heat generator (6) is designed in the manner of a hydraulic orifice with one or more flow openings. [3] Device according to claim 2, characterized by that the heat generator (6), designed in the manner of a hydraulic orifice, has a single flow opening. [4] Device according to one of claims 1 to 3, characterized by that the heat generator (6) is constructed from several hydraulic orifices connected in series. [5] Device according to one of claims 1 to 4, characterized bythat a relaxation section is provided between the last heat generator (6) in the flow direction of the liquid and the liquid storage (10). [6] Device according to one of claims 1 to 5, characterized by that a component providing a back pressure is connected downstream of a first heat generator (6). [7] Device according to claim 6, characterized by that the component providing the back pressure is an aggregate driven by the liquid jet emerging from the upstream heat generator (6). [8] Device according to claim 7, characterized by that the component providing the back pressure is a hydraulic axial piston motor (7). [9] Device according to claim 8, characterized by that a generator (8) is driven by the axial piston motor (7). [10] Device according to claim 7, characterized bythat the component providing the back pressure is a hydraulic motor (15) supporting the drive of the high-pressure pump (2.1). [11] Device according to one of claims 6 to 10, characterized by that the back pressure provided by the unit downstream of the heat generator (6) is lower than the back pressure caused by the upstream heat generator (6). [12] Device according to one of claims 1 to 5, characterized by that the liquid flow emerging from the at least one heat generator drives a rotatably driven unit, in particular a generator, which does not provide any significant counterpressure. [13] Device according to one of claims 1 to 12, characterized bythat the heat generator (6.2) is located in a housing (17), wherein a fluid path is provided between the housing and the heat generator (6.2) in order to use heat radiated by it in the manner of a heat exchanger and the housing (17) is connected to a heat exchanger circuit. [14] Device according to claim 13, characterized by that the heat generator (6.2) is connected to a heat exchanger circuit designed as a heat pump with a refrigerant as heat exchange fluid. [15] Device according to claim 14, characterized by that the housing (17) with the heat generator (6.2) located therein has an extension in the vertical direction, wherein the housing outlet from which the refrigerant evaporated by the heat of the heat generator (6.2) emerges is arranged in the upper end region of the housing (17) and the inlet of the liquid refrigerant is arranged in the lower end region of the housing (17). [16] Device according to one of claims 1 to 15 characterized by that the return (14) of the heating circuit (12) is connected to the inlet (4) of the pump (2). [17] Device according to one of claims 1 to 16, characterized by that a bypass line (11) connecting the liquid reservoir (10) to the inlet (4) and bypassing the heating circuit (12) is connected to the inlet (4) of the pump (2). [18] Device according to one of claims 1 to 17, characterized by that the liquid pumped by the high-pressure pump (2) is water or an aqueous solution.

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