Heat generator

Abstract

The invention relates to a heat generator 1 for a building, comprising at least one pressure vessel 10 for holding an aqueous solution and at least one heat exchanger 2, 4 for transferring the generated heat to a liquid transport medium of a closed heating circuit 3 or for heating a domestic hot water circuit 5. To provide a heat generator 1 without the use of fossil fuels or hydrogen gas, the invention provides that the pressure vessel 10 has at least two electrodes 11, 12, 13, 14, which project into the pressure vessel 10 and can be subjected to a voltage to generate a plasma discharge. By subjecting the electrodes 11, 12, 13, 14 to a voltage, a plasma is generated between the electrodes 11, 12, 13, 14, which leads to the direct heating of the aqueous solution.The aqueous solution is supplied to at least one heat exchanger 2,4 via control systems using a circulation pump 28, which is intended either for the heating circuit 3 or the domestic hot water circuit 5.

Description

[0001] The invention relates to a heat generator for a building, comprising at least one pressure vessel for receiving an aqueous solution and at least one heat exchanger for transferring the generated heat to a liquid transport medium of a closed heating circuit or for heating a domestic water circuit.

[0002] Heat generators for generating heat, for example, for a heating circuit or for heating domestic water, are available in a variety of forms. Most heat generators generate the necessary heat using fossil fuels, such as oil or gas. By burning the fuel, the fuel is oxidized through a thermal reaction, and the resulting process heat is transferred, for example, via a heat exchanger to a mostly liquid medium, to supply a building with hot water as well as heating energy.

[0003] Heat generators that can be operated at least partially or entirely with green hydrogen are currently being planned. Currently, hydrogen produced through electrolysis is mixed with a gas supply. Various suppliers offer gas boilers that can burn up to 20% hydrogen together with 80% gas. Green hydrogen is primarily produced through electrolysis of water, with electrical energy being generated, for example, by a photovoltaic system. The hydrogen produced in this way must be temporarily stored in pressure vessels with a high safety standard or, if appropriate pipelines are available, can be fed directly into a pipeline network to the end user.

[0004] DE 10 2022 116 119 B3 discloses the production of hydrogen and oxygen using the electrolysis process. The rising gases enter a liquid-free combustion chamber and are ignited there by a pilot flame. The heat generated can be transferred directly to a heat exchanger.

[0005] The operation of such a plant requires a high safety standard in order to absorb the gases resulting from electrolysis and to enable the combustion of the hydrogen in a controlled manner.

[0006] The present invention is based on the object of providing a novel heat generator which enables heat generation without the combustion of fossil fuels or hydrogen gas.

[0007] To achieve this objective, a pressure vessel is provided with at least two electrodes that extend into the pressure vessel and can be subjected to voltage to generate a plasma discharge. Further advantageous embodiments are set forth in the subclaims.

[0008] Compared to conventional heating units, not only is the use of fossil fuels dispensed with, but the combustion of hydrogen gas is also eliminated. This approach has the significant advantage that no gas storage is required, and a piping system to the respective end user is also eliminated. The heat generator has at least two electrodes, preferably four, or possibly six or eight, to which a voltage is applied, causing a plasma discharge between the individual electrodes. The resulting energy is used to heat the liquid medium within the pressure vessel, for example, water, which allows heat to be released via at least one heat exchanger.Heat can be transferred, for example, to a heating circuit to heat a building, but also to heat water so that the domestic water in the building can be heated to a desired temperature. Heating typically occurs up to a temperature of 35 to 40 degrees Celsius to prevent the risk of scalding. If higher water temperatures are present, the temperature is preferably reduced by a mixer tap that additionally supplies cold water. This allows the domestic water to be used for showering, bathing, and handwashing.

[0009] To supply domestic hot water, but especially for radiator heating or underfloor heating, the heat generator can be heated to up to 80°C, so that it can also supply conventional radiators. The boiler unit itself is filled with water, sealed, and has a 6 bar pressure relief opening to limit any expansion of the water in the radiator to 6 bar. The boiler unit is a standalone unit and can be refilled via filling hoses as needed. Refilling is done using a pump or manually via a funnel from above, for example by removing the vent opening. The boiler temperature is set to up to 80°C and has an immersion regulator on the rear of the boiler unit for temperature monitoring.The temperature is set manually, and in the event of a power failure, an overheating protection device at 95 °C intervenes, interrupting the power supply to the device to prevent steam from being generated in the device.

[0010] A particular advantage of the heat generator is that it does not require an external chimney, as no flue gases are emitted and therefore operates in an extremely environmentally friendly manner.

[0011] The hot boiler water is pumped through the flow and return assembly within the boiler unit by an internal pump, circulating the water and supplying the heat exchangers. A 3-bar mechanical pressure reducing valve is installed on the sealed side of the electric heater to eliminate any overpressure problems in the sealed secondary circuit. The sealed side of the boiler unit features a 7-liter inlet and outlet expansion tank with a 4-bar pressure relief port to absorb any expansion within the heating system's expansion tank and the heating unit, preventing overpressure.

[0012] The particular advantage of the present invention is that the generation of a plasma discharge allows for a direct, immediate energy transfer to the liquid medium in the pressure vessel, resulting in extremely low losses during the transfer process. The supplied electrical energy is used directly via the plasma to heat the aqueous solution, for example, in the form of water.

[0013] The electrodes inserted into the pressure vessel are subjected to a direct voltage, resulting in positive and negative electrodes serving as anodes and cathodes, respectively, which promote plasma development supported by the liquid medium. The number of electrodes and the size of the pressure vessel depend on the desired output of the heat generator to efficiently and without delay heat the liquid medium, which can then transfer the heat via the heat exchangers, for example, to the heating and domestic hot water system.

[0014] To operate the heat generator with a pressure vessel, it is further provided that the pressure vessel is fluidly connected to a heat exchanger for a building heating system and / or that the pressure vessel is fluidly connected to a heat exchanger for a hot water supply. Both variants are conceivable: the heat generator can supply the heating system exclusively, or the hot water supply exclusively, or both, if necessary.

[0015] To optimize heat exchange, a circulation pump is further provided in the circuit from the pressure vessel to the at least one heat exchanger, which can be activated via a control panel. The circulation pump ensures that the heated water in the pressure vessel continuously flows to the at least one heat exchanger.

[0016] In a further embodiment of the invention, the pressure vessel is equipped with a control system that regulates the pressure vessel temperature, the outlet temperature of the heat exchangers, the prevailing pressure conditions, and the requirements of the heating system and domestic water treatment. A control system enables time-dependent or demand-dependent control of the heat generator, whereby the control system enables regulation depending on the pressure vessel temperature, the outlet temperature of the heat exchangers, the prevailing pressure conditions, and the requirements of the heating system and domestic water treatment. In addition, by monitoring the temperature of the heating circuits, the control system can switch between continuous operation and pulsed operation of the heat generator depending on the heat demand.Heating the aqueous solution in the pressure vessel is only necessary when heat is actually required by the heating system or domestic hot water system. This allows the heat generator to operate in pulsed mode, where, for example, only a comfortable domestic hot water temperature is required during the summer months.

[0017] In a further embodiment, the pressure vessel is fluidically connected to an expansion tank and has a pressure relief valve. The expansion tank and the pressure relief valve can be used to limit the maximum pressure in the pressure vessel and prevent overpressure.

[0018] In a particular embodiment of the invention, it is provided that the electrodes consist of a magnesium sleeve, which can be used advantageously to generate a plasma between the positive and negative electrodes.

[0019] The present invention is further based on the object of demonstrating a method for operating the heat generator.

[0020] To solve the procedural problem, a method for operating a heat generator is provided, which comprises the following steps: Monitoring and control of the heat generator depending on the energy requirement by a control system. Applying a voltage to at least two electrodes of the pressure vessel. Generating a plasma between electrodes in the aqueous solution. Heating the aqueous solution in the pressure vessel using the plasma. Direct or indirect transfer of the heat of the aqueous solution to at least one heat exchanger.

[0021] Essentially, the method involves monitoring the heat generator using a control system and applying a voltage continuously or in a pulsed manner to at least two electrodes of the pressure vessel. This generates a plasma between the electrodes in the aqueous solution, which initially heats the aqueous solution using the plasma and is then used, via direct or indirect transfer of heat to at least one heat exchanger, either for a closed heating circuit or for heating domestic water.

[0022] Depending on the energy demand, the control system can be used to control continuous or pulsed operation of the heat generator. The heat flow into the heat exchanger can be optimized through controlled activation of at least one circulation pump, which is arranged in the supply line to the heat exchanger.

[0023] The particular advantage of the present invention is that a heat generator is operated using only electrical current, which completely dispenses with fossil fuels. The supplied electricity is supplied, for example, by a photovoltaic system, so that the heat generator can be operated independently of existing piping systems or power supply devices. For nighttime operation, it is necessary that the electrical energy generated by the photovoltaic system is stored in accumulators, if necessary. By heating the liquid medium in the pressure vessel using a plasma generated between electrodes, energy is transferred to the aqueous solution, in particular water, with high efficiency, thus minimizing any losses that may occur.

[0024] The invention is further explained below with reference to the figure.

[0025] This showsFig. 1 a block diagram of the heat generator and an associated heating circuit.

[0026] Figure 1shows a heat generator 1, which is connected to a heating circuit 3 via a first heat exchanger 2 and to an indicated domestic water circuit 5 via a heat exchanger 4. The heat generator 1 consists of a pressure vessel 10, which in the illustrated embodiment is equipped with electrodes 11, 12, 13, 14. The electrodes 11, 12, 13, 14 are installed almost vertically in the pressure vessel 10 and protrude into the existing volume. To operate the electrodes 11, 12, 13, 14, they are connected to electrical supply lines that are not shown in the block diagram. Via a control unit, also not shown, the electrodes 11, 12, 13, 14 can be supplied with voltage, so that a plasma discharge occurs between the electrodes 11, 12, 13, 14 within the pressure vessel 10. The plasma discharge is used to heat the aqueous solution in the pressure vessel 10.The pressure vessel 10 is connected to the two heat exchangers 2, 4 via a first supply line 15 and a second supply line 16. A circulation pump 17 is arranged in the flow circuit of the supply line 15 and is also controlled by the control device so that the heated aqueous solution is supplied to the two heat exchangers 2, 4. The pressure vessel 10 also has a safety valve 19 and a drain valve 20. An automatic vent valve 22 and an expansion tank 23 are connected to the pressure vessel 10 via a further supply line 21. With the help of the vent valve 22, which is typically designed for 10 bar, an excess pressure above a limit value can be released, with the expansion tank 23 previously being provided for pressure equalization below 10 bar.

[0027] The heating circuit 3 contains the heat exchanger 2, and an expansion tank 25 is provided for the heating circuit 3 via a supply line 24. Furthermore, the heating circuit 3 contains a pressure sensor 26 and a safety valve 27 for the heating system. The water in the heating circuit 3 is circulated via a further circulation pump 28. Furthermore, the heating circuit 3 contains a radiator 29, shown as an example; however, a correspondingly higher number of radiators 29 may be used.

[0028] The second heat exchanger 4 enables heating of the domestic water, which is first fed into an anti-limescale filter 31 via a supply line 30 and then reaches the heat exchanger 4 via a flow switch 32. On the output side, a supply line 33 connects to the existing domestic water circuit, which is not shown in further detail.

[0029] With the help of the heat generator 1 and the aqueous solution, preferably water, heated in the pressure vessel 10, heat is transported to the two heat exchangers 2, 4 to supply the heating circuit 3 on the one hand and the domestic water circuit 5 on the other. The pressure vessel 10 is further equipped only with a necessary drain valve 20 and a safety valve 19, as well as an expansion tank 23 and a vent valve 22 to ensure the required safety of the pressure vessel 10. The pressure vessel 10, with the connected valves and expansion tanks, represents the heat generator 1, which can be connected to standard pipes of the heating circuit 3 and the domestic water circuit 5. List of reference symbols

[0030] 1 Heat generator 2 Heat exchanger 3 Heating circuit 4 Heat exchanger 5 Domestic hot water circuit 10 Pressure vessel 11 Electrode 12 Electrode 13 Electrode 14 Electrode 15 Supply line 16 Supply line 17 Circulation pump 19 Safety valve 20 Drain valve 21 Supply line 22 Vent valve 23 Expansion tank 24 Supply line 25 Expansion tank 26 Pressure sensor 27 Safety valve 28 Circulation pump 29 Radiator 30 Supply line 31 Anti-limescale filter 32 Flow switch 33 Supply line

Claims

1. Heat generator (1) for a building, comprising at least one pressure vessel (10) for receiving an aqueous solution and at least one heat exchanger (2, 4) for transferring the generated heat to a liquid transport medium of a closed heating circuit (3) or for heating a domestic water circuit (5), characterized by that the pressure vessel (10) has at least two electrodes (11, 12, 13, 14) which project into the pressure vessel (10) and can be subjected to voltage to generate a plasma discharge.

2. Heat generator (1) according to claim 1, characterized by that the pressure vessel (10) has six to eight electrodes (11, 12, 13, 14) which are alternately supplied with direct voltage as anode or cathode.

3. Heat generator (1) according to claim 1 or 2, characterized by that the plasma is created between the electrodes (11, 12, 13, 14) with different voltage potential.

4. Heat generator (1) according to one of claims 1, 2 or 3, characterized by that the pressure vessel (10) is fluidically connected to a heat exchanger (2) for a building heating system, and / or that the pressure vessel (10) is fluidically connected to a heat exchanger (4) for a hot water supply.

5. Heat generator (1) according to one of claims 1 to 4, characterized by that a circulation pump (17) is arranged in the circuit from the pressure vessel (10) to the at least one heat exchanger (2, 4).

6. Heat generator (1) according to one of claims 1 to 5, characterized by that the pressure vessel (10) is equipped with a control system which carries out a control depending on the pressure vessel temperature, the outlet temperature of the heat exchangers (2, 4), the existing pressure conditions and the requirements of the heating circuit (3) and domestic water circuit (5).

7. Heat generator (1) according to one of claims 1 to 6, characterized by that the control system monitors the temperature of the heating circuit (3).

8. Heat generator (1) according to one of claims 1 to 7, characterized by that the control system switches between continuous operation and pulsed operation depending on the heat requirement.

9. Heat generator (1) according to one of claims 1 to 8, characterized by that the pressure vessel (10) is fluidically connected to an expansion vessel (23) and has a pressure relief valve.

10. Heat generator (1) according to one of claims 1 to 9, characterized by that the electrodes (11, 12, 13, 14) consist of a magnesium sleeve.

11. A method for operating a heat generator (1) according to one of claims 1 to 10, comprising the following steps: - monitoring and controlling the heat generator (1) as a function of the energy requirement by a control system - applying a voltage to at least two electrodes (11, 12, 13, 14) of the pressure vessel (10) - generating a plasma between the electrodes (11, 12, 13, 14) in the aqueous solution - heating the aqueous solution in the pressure vessel (10) with the aid of the plasma - directly or indirectly transferring the heat of the aqueous solution to at least one heat exchanger (2, 4).

12. Method according to claim 11, characterized by continuous operation or pulsed operation of the heat generator (1) depending on the heat requirement.

13. Method according to claim 11 or 12, characterized by controlled activation of at least one circulation pump (17).

14. Method according to claim 11, 12 or 13, characterized byActivation or deactivation of at least one circulation pump (17).

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