Device for heating ambient air and a liquid

Abstract

The invention relates to a device for heating ambient air and a liquid. A heat exchanger (6) transmits thermal energy to the liquid which is situated in a medium line (8). A medium container (7) receives liquid and air, and a conveying device (9) moves liquid and air from the medium container (7) to the medium line (8). If only ambient air is to be heated in an air mode, air from an air cushion (11) in the medium container (7) is moved through the medium line (8). The pump performance of the conveying device (9) is monitored in the process.

Description

[0001] The present invention relates to a device for heating room air and a liquid.

[0002] It is known in the prior art to obtain thermal energy from the combustion of, for example, propane, butane, gasoline, or diesel fuel converted into a gaseous state and to transfer it to a liquid, e.g., domestic hot water or room air, via at least one heat exchanger. It is also known to heat room air and liquids (see, e.g., US 2019 / 0212033 A1).

[0003] In the unpublished patent application number 10 2021 005 383.4, the applicant describes a device that allows the heating of liquid and ambient air. The device heats liquid contained in a medium line. If, in one operating mode, only air is to be heated instead of liquid, the medium line is emptied in a preparatory step by passing air through it. This air is different from the ambient air to be heated and can, for example, be referred to as working air. This air originates from an air cushion located in the medium container that holds the liquid to be heated and / or the heated liquid. The air is conveyed from the medium container back to the medium container through the medium line. This type of emptying requires that the device has a sufficient supply of working air.

[0004] From EP 2 614 971 A1, a heating device for a heat transfer medium is known, comprising a PTC element arranged between stacked electrode plates. The heating device also includes several heat exchange tubes through which the heat transfer medium flows, the heat exchange tubes being stacked parallel to one another. The electrode plates are arranged between the heat exchange tubes. A substrate is provided on the surface of the heat exchange tubes, which is connected to a heat-generating element and a press element.

[0005] The object underlying the invention is to propose a device for heating room air and a liquid, in which the emptying of the medium line by air is reliably ensured.

[0006] The invention solves the problem by a device for heating room air and a liquid, comprising an energy unit, a heat exchanger, a medium container, a medium line, a conveying device, and a control unit, wherein the energy unit generates thermal energy, wherein the heat exchanger transfers the thermal energy generated by the energy unit to the room air and the liquid, wherein the medium container serves to hold the liquid and air, wherein the medium line serves to convey the liquid and air, wherein the heat exchanger and the medium line are designed and arranged relative to each other such that the heat exchanger transfers thermal energy to the liquid located in the medium line, wherein the conveying device serves to move the liquid and air from the medium container to the medium line, and wherein the control unit is configured to control the conveying device, wherein in the case,that the device in an air mode is only intended to heat room air, the control unit is configured to control the conveying device in a preparatory step so that the conveying device moves air from an air cushion in the medium container through the medium line, and wherein the control unit is configured to monitor the pumping behavior of the conveying device.

[0007] The device according to the invention serves to heat ambient air and a liquid, comprising an energy unit, a heat exchanger, a medium reservoir, a medium line, a conveying device, and a control unit. The energy unit generates thermal energy—for example, by burning a gas / diesel / gasoline-air mixture or via an electric heating element—which the heat exchanger transfers to the ambient air and the liquid. Different operating modes are provided: for example, only ambient air or only liquid is heated, or both ambient air and liquid are heated. The liquid is, for example, process water. The medium reservoir holds both liquid and air. This air can also be referred to as working air and is not the ambient air that is to be heated by the device. However, this air can be drawn from the same space to which the ambient air is assigned.In one embodiment, the medium container has a liquid outlet for draining the liquid and an air inlet for admitting air. Additionally, in one embodiment, the medium container also has at least one liquid inlet through which, for example, warm or cold liquid can enter the medium container. Preferably, a drain valve is associated with the liquid outlet, allowing adjustment of whether and, if so, how much liquid flows out of the medium container via the liquid outlet. The medium line can carry liquid and air, and it and the heat exchanger are designed and arranged relative to each other such that the heat exchanger transfers thermal energy to the liquid in the medium line. Thus, the liquid flowing through the medium line is specifically heated.Additionally, the design includes a channel for ambient air through the device, allowing the heat exchanger to transfer thermal energy to the ambient air. A pumping device, controlled by the control unit, is provided to convey the liquid and air from the reservoir to the fluid line and through the fluid line. If only ambient air is to be heated in air mode, the control unit first empties the fluid line. To do this, the control unit regulates the pumping device so that it moves air from an air cushion in the reservoir through the fluid line. The air thus pushes the liquid out of the fluid line. However, sufficient air must be present in the system consisting of the reservoir, pumping device, and fluid line for this to work.Furthermore, the air must be conveyed through the medium line, or at least through the section of the medium line where the heat exchanger transfers thermal energy to the fluid, thus heating the fluid. The control unit monitors the pumping behavior of the conveying device for this purpose. This is achieved, for example, by using sensors that detect when air is being conveyed through the medium line. Alternatively or additionally, the performance of the conveying device is monitored, with one configuration, for example, evaluating the power consumption.

[0008] One embodiment consists of a medium container having a liquid outlet for draining the liquid and an air inlet for admitting air, a drain valve associated with the liquid outlet, and a control unit configured to actuate the drain valve so that liquid flows out of the medium container via the liquid outlet if the amount of air conveyed by the conveying device falls below a setpoint during the preparation step. In this embodiment, a drain valve is thus provided through which the draining of liquid from the medium container can be controlled. The drain valve is associated with the liquid outlet.

[0009] If the control unit detects that the required amount of air is not being supplied—that is, that the actual value of the supplied air volume is below a predefined target value, or even that no air is being supplied at all—it initiates a reaction in this configuration to ensure that sufficient air is available for the preparatory step. This reaction consists of the control unit opening the drain valve and allowing liquid to flow from the liquid outlet of the medium container. The outflow of liquid increases the portion of the internal volume in the medium container available for air. In one configuration, this allows more air to enter the system and be supplied through the medium line. For this air inflow, the air inlet is equipped with an air valve.

[0010] One embodiment provides for an air valve associated with the air inlet, through which air can enter and / or exit the medium container. The air valve is designed to open the air inlet when the pressure inside the medium container is lower than the atmospheric pressure outside. This air valve thus opens automatically depending on the conditions inside the medium container. The air and the liquid inside the medium container are at the same pressure. If this pressure is lower than the atmospheric pressure surrounding the medium container, the air valve opens automatically. This means that the outflow of liquid causes the valve to open, allowing air to enter the medium container.

[0011] One related design feature is that the air valve is designed as a ventilation valve.

[0012] Another approach involves an alternative design that also includes an air valve connected to the air inlet. In this design, the control unit is configured to actuate the air valve if the amount of air delivered by the conveying device falls below the target value during the preparation step, allowing air to enter the medium container via the air inlet. In this configuration, the control unit actively opens the air valve to allow air to enter the medium container.

[0013] The two different designs thus have in common that the outflow of the liquid is accompanied by the inflow of air through the air inlet into the medium container.

[0014] Another embodiment consists of a medium container having a liquid inlet, an associated inlet valve, and a control unit configured to close the inlet valve if the volume of air conveyed by the conveying device falls below the setpoint during the preparation step. In this embodiment, liquid can enter the medium container via a liquid inlet. To prevent the outflow of liquid through the liquid outlet from being compensated for by refilling via the liquid inlet—for example, by an automatically operating liquid pump—the control unit in this embodiment closes the liquid inlet via an inlet valve.

[0015] One embodiment provides that the control unit is configured to monitor the pumping behavior of the conveying device by evaluating the current consumption of the conveying device. In this embodiment, the control unit evaluates the current requirement of the conveying device, which is related to the medium being conveyed.

[0016] One related embodiment involves the control unit being configured to evaluate a decrease in the current draw of the conveying device to indicate that the device is conveying air. This embodiment thus exploits the fact that the conveying device requires significantly less energy when conveying air instead of liquid. Therefore, in a further development, a sudden drop in current draw is specifically used as a signal that air is being conveyed. However, if the current draw remains constant or decreases only slightly, it is recognized that little or no air is being conveyed. Thus, the invention also generally relates to detecting whether a conveying device is conveying air or liquid.

[0017] One embodiment provides that, if the device is intended to heat either only liquid or liquid and ambient air, the control unit is configured to control the conveying device so that liquid flows from the medium container to the medium line and from the medium line back to the medium container. In air mode, if only air is heated, no liquid is conveyed through the medium line. However, if liquid is to be heated, the liquid is moved through the medium line.

[0018] One embodiment of the device includes a blower for conveying room air from an air inlet to an air outlet. In this embodiment, room air is guided through the device, and thus preferably past the heat exchanger, in such a way that thermal energy is transferred to it and it is thereby heated.

[0019] One embodiment involves the energy unit generating thermal energy by burning a fuel-air mixture and / or by converting electrical energy.

[0020] In detail, there are numerous possibilities for designing and further developing the device according to the invention. Reference is made, on the one hand, to the claims subordinate to claim 1, and on the other hand, to the following description of exemplary embodiments in conjunction with the drawing. It shows: Fig. 1 is a schematic representation of a device.

[0021] The Fig. 1 schematically shows the structure of a device for heating room air and a liquid.

[0022] Room air enters the device through air inlet 1 and exits, warmed, through air outlet 2. A blower 12 directs the room air past the heat exchanger 6, where it absorbs the thermal energy from the energy unit 5. The energy unit 5 generates this thermal energy, for example, by burning a fuel-air mixture, where the fuel is, for example, propane, butane, diesel, or gasoline. The liquid is heated by being conveyed by the pump 9 through the medium line 8. The design of the medium line 8 and the heat exchanger 6 allows the thermal energy to be transferred to the liquid. The liquid is conveyed from a medium reservoir 7 to the medium line 8 and back again. The medium reservoir 7 has an inlet and an outlet, which are not shown for clarity.

[0023] The illustrated embodiment includes a liquid outlet 3, a liquid inlet 13, and an air inlet 4: Liquid can be drained from the medium container 7 through the liquid outlet 3. To enable or prevent this, a drain valve 30 is provided, which is controlled by the control unit 10. Air can enter the medium container 7 through the air inlet 4. In the illustrated embodiment, the control unit 10 acts on an air valve 40 to control this air inlet. In an alternative embodiment—not shown here—the air valve 40 opens automatically by being designed as a vent valve that reacts to liquid flowing from the medium container 7. The liquid inlet 13 allows liquid to flow into the medium container 7—for example, via another pump (not shown here).This is, for example, cold liquid that is to be heated by the device. The control unit 10 can open and close the liquid inlet 13 via an inlet valve 130. The medium container 7 thus receives liquid and air. The air is indicated here by the formation of an air cushion 11. If only the room air is to be heated in an air mode, the medium line 8 is first cleared of liquid in a preparatory step. This is done by passing the air from the air cushion 11 through the medium line 8. The conveying device 9 is accordingly capable of conveying both air and liquid.

[0024] The control unit 10 controls the conveying device 9 and monitors its pumping capacity. In the illustrated version, this is achieved by evaluating the power consumption of the conveying device 9. If the power consumption of the conveying device 9 falls below a predefined value, the control unit 10 infers that a sufficient quantity of air is being conveyed through the medium line 8. If there is no reduction in power consumption, or only an insufficient reduction, the control unit 10 concludes that no or insufficient air is being conveyed. In this case of insufficient air volume, air is introduced into the medium container 7, which is then conveyed by the conveying device 9. Thus, a kind of refilling of the working air takes place.

[0025] This is achieved by the control unit 10 opening the drain valve 30 and the air valve 40. In the previously mentioned (but not shown) embodiment, the air valve 40 opens automatically as a result of the liquid flowing out of the medium container 7. Furthermore, the control unit 10 closes the liquid inlet 13 by means of the inlet valve 130, so that the outflow of liquid through the liquid outlet 3 is not compensated for by liquid flowing in through the liquid inlet 13. The outflow of liquid is intended to draw air into the medium container 7. This occurs through the open air valve 40.

Claims

1. A device for heating room air and a liquid, comprising an energy unit (5), a heat exchanger (6), a medium tank (7), a medium line (8), a conveying device (9) and a control unit (10), wherein the energy unit (5) generates thermal energy, wherein the heat exchanger (6) transfers the thermal energy generated by the energy unit (5) to the room air and the liquid, wherein the medium tank (7) serves to take up liquid and air, wherein the medium line (8) serves to conduct liquid and air, wherein the heat exchanger (6) and the medium line (8) are configured and arranged relative to each other such that the heat exchanger (6) transfers thermal energy to liquid present in the medium line (8), wherein the conveying device (9) serves to move liquid and air from the medium tank (7) to the medium line (8), characterized in that the control unit (10) is configured to control the conveying device (9), wherein in the event that the device is intended to heat only room air in an air mode, the control unit (10) is configured to control the conveying device (9) in a preparatory step such that the conveying device (9) moves air from an air cushion (11) in the medium tank (7) through the medium line (8), and wherein the control unit (10) is configured to monitor a pumping behavior of the conveying device (9).

2. The device according to claim 1, wherein the medium tank (7) has a liquid outlet (3) for draining the liquid and an air inlet (4) for admitting air, wherein a drain valve (30) is assigned to the liquid outlet (3), and wherein in the event that an amount of air conveyed by the conveying device (9) is below a set value during the preparatory step, the control unit (10) is configured to control the drain valve (30) such that liquid flows out of the medium tank (7) via the liquid outlet (3).

3. The device according to claim 1 or 2, wherein an air valve (40) is assigned to the air inlet (4), and wherein the air valve (40) is configured such that the air valve (40) opens the air inlet (4) for air when a pressure in the medium tank (7) is below a pressure of the air outside the medium tank (7).

4. The device according to claim 3, wherein the air valve (40) is configured as a ventilation valve.

5. The device according to claim 1 or 2, wherein an air valve (40) is assigned to the air inlet (4), and wherein in the event that the amount of air conveyed by the conveying device (9) is below the set value during the preparatory step, the control unit (10) is configured to control the air valve (40) such that air enters the medium tank (7) via the air inlet (4).

6. The device according to any of claims 1 to 5, wherein the medium tank (7) has a liquid inlet (13), wherein a supply valve (130) is assigned to the liquid inlet (13), and wherein in the event that the amount of air conveyed by the conveying device (9) is below the set value during the preparatory step, the control unit (10) is configured to close the supply valve (130).

7. The device according to any of claims 1 to 6, wherein the control unit (10) is configured to monitor the pumping behavior of the conveying device (9) in that the control unit (10) evaluates a current consumption of the conveying device (9).

8. The device according to claim 7, wherein the control unit (10) is configured to evaluate a decrease in the current consumption of the conveying device (9) as meaning that the conveying device (9) conveys air.

9. The device according to any of claims 1 to 8, wherein in the event that the device is intended to heat only liquid or liquid and room air, the control unit (10) is configured to control the conveying device (9) such that liquid flows out of the medium tank (7) to the medium line (8), and from the medium line (8) to the medium tank (7).

10. The device according to any of claims 1 to 9, wherein the device further includes a fan (12) for conveying the room air from an air input (1) to an air output (2).

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