DEVICE FOR HEATING AIR

Description

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

[0002] It is known in the art to obtain thermal energy from the combustion of, for example, propane, butane, gasoline, or diesel fuel and to transfer it via a heat exchanger to a fluid, e.g., a liquid such as water or air (see, e.g., DE 10 2019 006 554 A1, DE 42 42 382 A1, DE 11 2018 003 288 T5, US 6,295,937 B1, or DE 10 2015 255 896 A1). Propane and butane are introduced in gaseous form. Diesel is introduced in liquid form and evaporates upon heating. It is also known that such devices can heat both a liquid and ambient air. The thermal energy generated by a burner is transferred by the heat exchanger to the air, which is circulated past the heat exchanger by a fan. The recirculating air fan also ensures that heat is removed from the heat exchanger. If the recirculating air fan malfunctions, the heat exchanger can be damaged.In particular, US 6,295,937 B1 discloses a generic device for heating air.

[0003] The object underlying the invention is to propose a device for heating air in which the functioning of the device and in particular of the circulating air blower is monitored.

[0004] The invention solves the problem by means of a device for heating air, comprising a housing, a burner, a combustion air blower, a combustion air supply, a fuel supply, a flue gas discharge, a heat exchanger, a recirculating air blower, a temperature sensor, a data storage device, and a monitoring unit, wherein the housing comprises at least the burner, the combustion air blower, the fuel supply, the heat exchanger, and the recirculating air blower, wherein the burner generates thermal energy by burning a fuel-combustion air mixture, wherein the combustion air blower supplies combustion air to the burner from the combustion air supply, wherein the fuel supply provides fuel to the burner, wherein the flue gas discharge removes flue gas produced by burning the fuel-combustion air mixture, and wherein the heat exchanger transfers the thermal energy to the air to be heated.wherein the recirculating air blower supplies the air to be heated to the heat exchanger, wherein the temperature sensor measures the temperature of the combustion air, wherein the monitoring unit evaluates the measured values ​​of the temperature sensor using data stored in the data memory, wherein the monitoring unit monitors the device - preferably the recirculating air blower - based on the evaluation, wherein the monitoring unit evaluates the measured values ​​to determine whether a temperature limit has been exceeded, wherein, in the event that the temperature limit 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 and generates a comparison result, and wherein, in the event that the comparison result indicates that the gradient limit has been exceeded, the monitoring unit signals an error.

[0005] In the device according to the invention, the device, or preferably specifically the recirculating air blower, is monitored by evaluating the temperature of the combustion air. This indirectly monitors whether the heat exchanger receives sufficient cooling from the air supplied by the recirculating air blower. The combustion air is the air that is introduced into the device to form the mixture with the fuel that is burned in the burner.

[0006] In the device according to the invention, the monitoring unit becomes active when a temperature limit is exceeded. If the temperature sensor has measured an excessively high temperature, the next step involves determining a temperature gradient. This determines the extent to which the temperature changes over a predetermined time interval. The temperature gradient (e.g., in °C per second) is then compared to a gradient limit. The signaled fault is preferably a fault in the recirculating air fan. This signaling is based on the understanding that a greater temperature increase occurs when the recirculating air fan is not operating or is operating insufficiently, and therefore cannot adequately cool the heat exchanger or the device. If the temperature gradient is greater than the gradient limit, the device is obviously heating up too quickly.This is attributed to a fault, for example, in the recirculating air fan. Therefore, the monitoring unit signals that such a fault exists. In one design, this signaling takes the form of interrupting the burner's combustion process.

[0007] In one embodiment, the device allows the heating of both air and a liquid, e.g. water.

[0008] One embodiment provides that the device can be operated at several power levels, and that the power levels can be selected via an adjustment device. In this embodiment, the device can be operated at different power levels (e.g., 2 kW, 3 kW, etc.), which can be selected by a user.

[0009] One configuration involves the monitoring unit evaluating the measured values ​​depending on the selected power level. In this configuration, the temperature sensor readings are evaluated based on the current power level. Therefore, the monitoring unit always has data available regarding which power level has been selected and which performance requirements the devices currently have to meet.

[0010] One embodiment provides that the monitoring unit evaluates the measured values ​​as a function of the outside temperature. This embodiment takes into account that the outside temperature has a certain effect on the behavior of the device. The outside temperature refers at least to the area outside the device and preferably to the area around the space whose air the device heats. For example, if the device heats the air inside a caravan or motorhome, the outside temperature refers to the environment around the caravan or motorhome.

[0011] In one embodiment, the outside temperature is measured by the temperature sensor. The combustion air is preferably drawn from the outside. If the temperature of the combustion air is measured during a preparatory step before the combustion process begins, this measurement is used as a measure of the outside temperature in one embodiment. In an alternative embodiment, a separate temperature sensor is provided to measure the outside temperature.

[0012] One embodiment provides that the temperature limit and / or the gradient limit depend on the selected power level and / or the outside temperature. In this embodiment, the parameter data for activation and / or detection of a device fault, or in one embodiment specifically the recirculating air fan, are used depending on the current power level and / or the outside temperature. This takes into account that the device behaves differently depending on the power level or the outside temperature, and that different temperatures or temperature gradients occur. Thus, for example, the monitoring unit retrieves a suitable value from the data memory as the temperature limit or gradient limit, depending on the outside temperature and / or the power level.

[0013] A designThis design involves the combustion air supply and the flue gas exhaust being configured and arranged relative to each other in such a way as to enable the transfer of thermal energy between the flue gas and the combustion air. In this configuration, the flue gas exiting the device heats the combustion air that is introduced into the device from the outside.

[0014] 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 the independent claim, 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.

[0015] The Fig. 1This diagram schematically shows the setup of a device for heating air and a liquid. The air, for example, is the air inside a caravan or motorhome. The two connections indicated – here on the right – are connected to the outside environment surrounding the space, i.e., the caravan or motorhome. The components of the device are described here in terms of their functional interaction.

[0016] The device has a housing 1. Inside is a burner 2, which is supplied with combustion air by a combustion air blower 3 and with fuel, e.g., diesel fuel, by a fuel supply 5. The resulting mixture is burned in the burner 2 to release thermal energy. The heat exchanger 7 transfers this thermal energy to the room air, which is drawn past it by the recirculating air blower 8. During combustion, the burner 2 also produces flue gas, which, after passing through the heat exchanger 7, is discharged from the device and also from the room, whose air is heated, via a flue gas outlet 6. The flue gas outlet 6 is designed to transfer any remaining thermal energy to the combustion air in the combustion air supply 4, thus preheating it. The power output of the device can be set by the user via the adjustment device 12.This is shown here as an example, separate from the device.

[0017] If the recirculating air blower 8 malfunctions, the heat exchanger 7 will not dissipate thermal energy and may be damaged. To prevent this, the temperature of the supplied combustion air 3 is measured by the temperature sensor 9. In this configuration, the temperature sensor 9 is located inside the housing 1 and therefore measures the temperature of the combustion air within the housing 1.

[0018] In the illustrated embodiment, the relationship between the heat exchanger 7 and the temperature of the combustion air is such that the heat exchanger 7 also heats the interior of the housing 1 and thus affects the air circulating within the housing 1. Furthermore, if the recirculating air fan 8 is not functioning or is malfunctioning, the flue gas has a higher thermal energy, which is transferred to the incoming combustion air via the flue gas exhaust system 6 and the combustion air supply system 4.

[0019] The monitoring unit 11 evaluates the measured values ​​of the temperature sensor 9, retrieving reference values ​​from a data storage device 10. It also receives information from the setting device 12 about the current power level. In the illustrated embodiment, the monitoring unit 11 and the data storage device 10 are separate from the housing 1. In an alternative embodiment (not shown), the monitoring unit 11 and the data storage device 10 are located inside or attached to the housing 1.

[0020] The monitoring unit 11 requires reference data from the data storage 10. This data depends on the current power level and the outside temperature of the room heated by the device. The outside temperature describes the temperature of the combustion air outside the room, and specifically before it interacts with the device and its components. The reference data consists of a temperature limit and a gradient limit.

[0021] If the temperature exceeds the temperature limit, the monitoring unit 11 becomes active and determines the extent of the temperature change. In other words, the temperature gradient is determined. If this gradient is above the gradient limit, this indicates that the device is heating up too quickly and that insufficient thermal energy is being dissipated. Therefore, this suggests that the recirculating air fan 8 is not working or is not working sufficiently.

Claims

1. A device for heating air, comprising a housing (1), a burner (2), a combustion air fan (3), a combustion air supply (4), a fuel supply (5), a flue gas discharge (6), a heat exchanger (7), an air circulation fan (8), a temperature sensor (9), a data memory (10), and a monitoring unit (11), wherein the housing (1) comprises at least the burner (2), the combustion air fan (3), the fuel supply (5), the heat exchanger (7), and the air circulation fan (8), wherein the burner (2) generates thermal energy by combusting a fuel-combustion air mixture, wherein the combustion air fan (3) supplies combustion air from the combustion air supply (4) to the burner (2), wherein the fuel supply (5) supplies fuel to the burner (2), wherein the flue gas discharge (6) discharges flue gas produced by the combustion of the fuel-combustion air mixture, wherein the heat exchanger (7) transfers the thermal energy to the air to be heated, wherein the air circulation fan (8) supplies the air to be heated to the heat exchanger (7), wherein the temperature sensor (9) measures a temperature of the combustion air, wherein the monitoring unit (11) evaluates the measured values of the temperature sensor (9) using data that is stored in the data memory (10), wherein, based on the evaluation, the monitoring unit (11) monitors the device - preferably the air circulation fan (8), characterized in that the monitoring unit (11) 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 (11) determines a temperature gradient from the measured values, wherein the monitoring unit (11) compares the temperature gradient as determined 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 (11) signals an error - preferably an error of the air circulation fan (8).

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 means of an adjusting device (12), and wherein the monitoring unit (11) evaluates the measured values as a function of the selected power level.

3. The device according to claim 1 or 2, wherein the monitoring unit (11) evaluates the measured values as a function of an outside temperature.

4. The device according to claim 1, wherein the temperature limit value and / or the gradient limit value are / is dependent on the selected power level and / or the outside temperature.

5. The device according to any of claims 1 to 4, wherein the combustion air supply (4) and the flue gas discharge (6) 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.