DEVICE FOR HEATING AIR

Abstract

The present disclosure relates to a device for heating air. A temperature sensor measures a temperature of the combustion air which is supplied to a burner. A monitoring unit evaluates the measured values in order to monitor the device.

Description

FIELD OF DISCLOSURE

The present disclosure relates to a device for heating air.

BACKGROUND

It is known in the prior art to obtain thermal energy from the combustion of, for example, propane, butane, gasoline or diesel fuel and to transfer it to a fluid, e.g. a liquid such as water or, e.g., air by means of a heat exchanger (see, e.g., DE 10 2019 006 554 A1, DE 42 42 382 A1, or DE 11 2018 003 288 T5). Propane and butane are introduced in gaseous form here. Diesel is introduced in liquid form and vaporizes through heating. It is also known that such devices can both heat a liquid and warm up room air. The thermal energy generated by a burner is transferred from the heat exchanger to the air, which is transported past the heat exchanger by an air circulation fan. The air circulation fan thus also ensures that heat is removed from the heat exchanger. If the air circulation fan does not function properly, the heat exchanger may get damaged.

Accordingly, there is a need to propose a device for heating air in which the operation of the device and, in particular, of the air circulation fan is monitored.

SUMMARY

The present disclosure achieves the object by providing a device for heating air, including a housing, a burner, a combustion air fan, a combustion air supply, a fuel supply, a flue gas discharge, a heat exchanger, an air circulation fan, a temperature sensor, a data memory, and a monitoring unit, wherein the housing comprises at least the burner, the combustion air fan, the fuel supply, the heat exchanger, and the air circulation fan, wherein the burner generates thermal energy by combusting a fuel-combustion air mixture, wherein the combustion air fan supplies combustion air from the combustion air supply to the burner, wherein the fuel supply supplies fuel to the burner, wherein the flue gas discharge discharges flue gas produced by the combustion of the fuel-combustion air mixture, wherein the heat exchanger transfers the thermal energy to the air to be heated, wherein the air circulation fan supplies the air to be heated to the heat exchanger, wherein the temperature sensor measures a temperature of the combustion air, wherein the monitoring unit evaluates the measured values of the temperature sensor using data that is stored in the data memory, and wherein, based on the evaluation, the monitoring unit monitors the device-preferably the air circulation fan.

In the device according to the present disclosure, the device or, preferably, the air circulation fan in particular is monitored by evaluating the temperature of the combustion air. In this way, it is indirectly monitored whether the heat exchanger is sufficiently cooled by the air that is conveyed by the air circulation fan. Here, the combustion air is the air that is introduced into the device to form, together with the fuel, the mixture that is combusted in the burner.

In one configuration, the device allows both air and a liquid, e.g. water, to be heated.

One configuration provides that the device is adapted to be operated at a plurality of power levels and that the power levels can be selected by means of an adjusting device. In this configuration, the device may be operated at different power levels (e.g., 2 KW, 3 KW, etc.), which are selectable by a user.

In one configuration, the monitoring unit evaluates the measured values as a function of the selected power level. In this configuration, the measured values of the temperature sensor are evaluated as a function of the respective current power level. The monitoring unit therefore has respective data available about which power level has been selected and which power requirements the device currently has to satisfy.

One configuration provides that the monitoring unit evaluates the measured values as a function of an outside temperature. In this configuration, it is taken into account that the outside temperature has a certain effect on the behavior of the device. The outside temperature here refers at least to the area outside the device and preferably to the area around the room the room air of which is heated by the device. For example, if the device heats the room air of a caravan or a motorhome, the outside temperature refers to the environment around the caravan or motorhome.

In one configuration, the outside temperature is sensed by the temperature sensor. The combustion air is preferably taken from the outside area. If the temperature of the combustion air is measured during a preparatory step before a combustion process is started, this is used in one configuration as a measure of the outside temperature. In an alternative configuration, a separate temperature sensor is provided which senses the outside temperature.

In one configuration, the monitoring unit evaluates the measured values with a view to whether a temperature limit value has been exceeded, wherein in the event that the temperature limit value has been exceeded, the monitoring unit determines a temperature gradient from the measured values, wherein the monitoring unit compares the determined temperature gradient with a gradient limit value and generates a comparison result, and wherein in the event that the comparison result signifies that the gradient limit value has been exceeded, the monitoring unit signals an error. In the configuration, the monitoring unit becomes active when a limit temperature value has been exceeded. That is, if the temperature sensor has measured a temperature that is too high, a temperature gradient is determined in the next step. This means that it is established by which extent the temperature develops in a specified time interval. The temperature gradient (e.g. in the unit degree Celsius per second) is then compared with a gradient limit value. In one configuration, the error signaled involves an error of the air circulation fan. This signaling is based on the finding that a greater increase in temperature will occur if the air circulation fan does not work or does not work sufficiently and cannot therefore provide for sufficient cooling of the heat exchanger and/or the device. If the temperature gradient is greater than the gradient limit value, the device obviously heats up too quickly. This is attributed to the fact that there is a fault, e.g. of the air circulation fan. In this case, the monitoring unit therefore signals that there is such a fault. In one configuration, the signaling consists in that a burning process of the burner is interrupted.

One configuration provides that the temperature limit value and/or the gradient limit value are/is dependent on the selected power level and/or the outside temperature. In this configuration, the parameter data for becoming active and/or for realizing that there is a fault of the device or, in one configuration, of the air circulation fan in particular, is used as a function of the current power level and/or the outside temperature. In this way, consideration is given to the fact that the device behaves differently depending on the power level and/or the outside temperature and that other temperatures or temperature gradients occur. Thus, for example, the monitoring unit takes a suitable value from the data memory as a temperature limit value or gradient limit value depending on the outside temperature and/or the power level.

In one configuration, the combustion air supply and the flue gas discharge are configured and arranged in relation to each other such that a transfer of thermal energy between the flue gas and the combustion air is allowed. In this configuration, the flue gas exiting the device heats the combustion air, which is introduced into the device from outside.

BRIEF DESCRIPTION OF DRAWINGS

In detail, there are a large number of possibilities for further designing and developing the device according to the present disclosure. In this regard, reference is made on the one hand to the claims that are dependent on the independent claim, on the other hand to the following description of exemplary embodiments in conjunction with the drawing, in which:

FIG. 1 shows a schematic illustration of a device.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 schematically shows the structure of a device for heating air and a liquid. The air is, for example, the room air of a caravan or motorhome. The two connections indicated—here on the right-hand side—are connected to the environment surrounding the room, i.e. around the caravan or motorhome. The components of the device are described here in terms of their functional cooperation.

The device has a housing 1. Located therein is a burner 2, which is supplied with combustion air by a combustion air fan 3 and with a fuel, e.g. diesel fuel, by a fuel supply 5. The resulting mixture is combusted in the burner 2 to release thermal energy. The heat exchanger 7 transfers the thermal energy to the room air which is led past it by the air circulation fan 8. During combustion, the burner 2 also generates a flue gas, which is discharged from the device and also from the interior, the air of which is heated, downstream of the heat exchanger 7 via a flue gas discharge 6. The flue gas discharge 6 is configured in such a way here that it can transfer a remaining thermal energy to the combustion air in the combustion air supply 4 and thus preheat it. The power level of the device can be preset by a user by means of the adjusting device 12 which, by way of example, is configured to be separate from the device here.

If the air circulation fan 8 does not operate properly in the event of a fault, the thermal energy is not dissipated from the heat exchanger 7 and it may be damaged. To prevent this, the temperature of the combustion air 3 supplied is measured using the temperature sensor 9. In this configuration, the temperature sensor 9 is arranged in the interior of the housing 1 and therefore measures the temperature of the combustion air within the housing 1.

The relationship between the heat exchanger 7 and the temperature of the combustion air is given in the illustrated embodiment in that the heat exchanger 7 also heats the interior of the housing 1 and thus has an effect on the air conducted within the housing 1. Furthermore, if the circulating air fan 8 is not working or is not working properly, the flue gas has a higher thermal energy, which is transferred to the inflowing combustion air by the system made up of the flue gas discharge 6 and the combustion air supply 4.

The monitoring unit 11 evaluates the measured values of the temperature sensor 9, taking reference values from a data memory 10. In addition, it receives information from the adjusting device 12 about which power level is the current one. In the embodiment illustrated, the monitoring unit 11 and also the data memory 10 are offset from the housing 1. In an alternative design—not illustrated—the monitoring unit 11 and the data memory 10 are located in or at the housing 1.

The monitoring unit 11 requires reference data from the data memory 10, the reference data depending on the current power level and the outside temperature outside the room that is heated by the device. The outside temperature describes which is the temperature of the combustion air outside the room and, in particular, before an interaction with the device and its components. The reference data is, for one, a temperature limit value and, for another, a gradient limit value.

When the temperature exceeds the temperature limit value, the monitoring unit 11 becomes active and determines the extent by which the temperature develops. This means that the gradient of the temperature is determined. If this gradient is above the gradient limit value, this is an indication that the device heats up too quickly and that not sufficient thermal energy is dissipated. This is therefore an indication that the air circulation fan 8 does not work or does not work sufficiently.

While the disclosure has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. A device for heating air, comprising:

a housing, a burner, a combustion air fan, a combustion air supply, a fuel supply, a flue gas discharge, a heat exchanger, an air circulation fan, a temperature sensor, a data memory, and a monitoring unit,

wherein the housing comprises at least the burner, the combustion air fan, the fuel supply, the heat exchanger, and the air circulation fan,

wherein the burner generates thermal energy by combusting a fuel-combustion air mixture,

wherein the combustion air fan supplies combustion air from the combustion air supply to the burner,

wherein the fuel supply supplies fuel to the burner,

wherein the flue gas discharge discharges flue gas produced by the combustion of the fuel-combustion air mixture,

wherein the heat exchanger transfers the thermal energy to the air to be heated,

wherein the air circulation fan supplies the air to be heated to the heat exchanger,

wherein the temperature sensor measures a temperature of the combustion air,

wherein the monitoring unit evaluates the measured values of the temperature sensor using data that is stored in the data memory, and

wherein, based on the evaluation, the monitoring unit monitors the device-preferably the air circulation fan.

2. The device according to claim 1,

wherein the device is adapted to be operated at a plurality of power levels,

wherein the power levels can be selected by an adjusting device, and

wherein the monitoring unit evaluates the measured values as a function of the selected power level.

3. The device according to claim 1,

wherein the monitoring unit evaluates the measured values as a function of an outside temperature.

4. The device according to claim 1,

wherein the monitoring unit evaluates the measured values with a view to whether a temperature limit value has been exceeded,

wherein in the event that the temperature limit value has been exceeded, the monitoring unit determines a temperature gradient from the measured values,

wherein the monitoring unit compares the determined temperature gradient with a gradient limit value and generates a comparison result, and

wherein in the event that the comparison result means that the gradient limit value has been exceeded, the monitoring unit signals an error-preferably an error of the air circulation fan.

5. The device according to claim 4, wherein the temperature limit value and/or the gradient limit value are/is dependent on the selected power level and/or the outside temperature.

6. The device according to claim 1, wherein the combustion air supply and the flue gas discharge are configured and arranged in relation to each other such that a transfer of thermal energy between the flue gas and the combustion air is allowed.