Method and system for accelerating and diluting an exhaust air stream

Abstract

Method for accelerating and diluting an exhaust air stream (4), comprising: - Accelerating an airflow (10) with an airflow blower system (11), - Aligning the accelerated airflow (10) with an exhaust airflow (4) exiting from an exhaust air outlet (8) such that a - Acceleration and dilution of the exhaust air stream (4) downstream of the exhaust air stream outlet (8) by the accelerated air stream (10) is carried out, characterized in that an ambient pressure and / or a wind speed is detected and that the power of the air stream blower system (11) is regulated depending on the ambient pressure and / or the wind speed.

Description

[0001] The present invention relates to a method for accelerating and diluting an exhaust air stream according to the preamble of claim 1 and to a system for carrying out the method.

[0002] A common problem in urban areas is exhaust air emissions from indoor spaces, particularly from private and commercial kitchens. This exhaust air contains grease, dirt, and odors that can contaminate neighboring buildings through deposits and are perceived and disturbed by people in the vicinity.

[0003] To reduce the disadvantages of exhaust air emissions, solutions are known which mix fresh air into the exhaust air before it is released into the environment, thereby diluting the exhaust air and reducing odor nuisance.

[0004] DE 27 59 072 A1 discloses a device for preventing odor nuisances in stables. For this purpose, fresh air is supplied to the exhaust air of the stable via fresh air ducts that are directed upwards in a nozzle-like manner from bottom to top into a deflector hood at the end of a ventilation shaft.

[0005] German patent DE 26 07 712 A1 describes an exhaust air mixing hood for a fireplace, which has a circumferential opening for drawing in outside air. The outside air is drawn in by a suction effect and mixes with the chimney exhaust air, so that its pollutant concentration can be reduced when it leaves the hood.

[0006] DD 2 19 053 A3 discloses a device for mixing exhaust air with ambient air. The device comprises a jacket section which is arranged in the direction of flow above the end of an exhaust pipe, so that ambient air is drawn in, which is intended to contribute to cooling the exhaust pipe.

[0007] From DE 42 11 755 A1 and US 4 654 508 A, ovens with an air extraction device are known which allows fumes or exhaust air to enter a flow shaft via an inlet point, whereby the fumes or exhaust air are drawn into the shaft by a suction effect.

[0008] DE 20 2007 012 095 U1 describes a constant air system for an extractor hood, which includes an exhaust air device and a supply air device designed in such a way that the amount of exhausted air is provided by at least the same amount of supplied air.

[0009] CN 2 06 973 657 U describes an exhaust system in which compressed air is blown through a nozzle into an annular channel by means of a compressor, so that smoke or (oil) vapors are extracted. A small volume of compressed air is used to move a multiple of the exhaust air.

[0010] In the aforementioned publications, the dilution of the exhaust air is achieved by drawing fresh air along with the accelerated exhaust air, followed by a mixing of the two. However, the mere dilution of the exhaust air is generally insufficient to overcome the disadvantages of continuous exhaust air emissions described above.

[0011] Therefore, further efforts were undertaken to treat the exhaust air in such a way that the disruptive grease, dirt, and odor components are removed before being released into the environment. For example, DE 10 2012 012 689 A1 describes a method for operating a kitchen exhaust system in which the kitchen exhaust air is treated with a cleaning agent before it reaches the exhaust duct.

[0012] However, such processes are very complex and involve high operating costs, as the cleaning agent is a consumable. Furthermore, the exhaust system itself is complex and requires intensive maintenance, since components within the exhaust duct must be cleaned regularly.

[0013] It is therefore an object of the present invention to provide an efficient method which reduces the exhaust air emissions from interior spaces, in particular from kitchens and / or cooking areas, for neighboring buildings and the people staying in the vicinity at least to such an extent that these emissions are no longer perceived as disturbing or at least no longer perceived as disturbing.

[0014] This problem is solved by a method having the features of claim 1.

[0015] The method according to the invention comprises accelerating an airflow with an airflow blower system and aligning the accelerated airflow to an exhaust airflow exiting an exhaust air outlet, so that the exhaust airflow is accelerated downstream of the exhaust air outlet by the accelerated airflow.

[0016] The invention is based on the fundamental idea that the exhaust air is carried away from the emission source, in particular the exhaust air outlet, by the airflow, thus preventing disturbance of the environment surrounding the emission source. This prevents unpleasant odors and environmental pollution caused by grease, dirt, and odorous components carried along in the exhaust air.

[0017] Visually, the airflow used according to the invention performs a function that is usually performed by chimneys, namely to provide buoyancy for the exhaust airflow and furthermore to allow the exhaust air to spread only at a distance and thus at a degree of dilution at which the exhaust air is no longer perceived as disturbing.

[0018] Furthermore, it is advantageous that the method according to the invention can be used without maintenance- and cost-intensive exhaust air purification processes or devices, since no system components are touched by the exhaust air stream. Therefore, retrofitting existing exhaust air systems is also cost-effective, and no parts that could become contaminated by the exhaust air stream are used or required, which would necessitate increased maintenance and cleaning efforts.

[0019] Finally, the invention allows for a largely invisible distance of the exhaust air from the emission source, which can be an important criterion, especially for prestigious buildings, such as hotel complexes.

[0020] In general, accelerating the exhaust airflow through an accelerated airflow refers to an increase in the volumetric flow rate of the exhaust air compared to a non-accelerated exhaust airflow. The volumetric flow rate can be measured, for example, using a flow meter. Preferably, the volumetric flow rate is determined using a non-contact flow meter, such as an ultrasonic flow meter. This has the advantage of preventing contamination from grease, dirt, and odors carried in the exhaust airflow. Alternatively, the volumetric flow rate can also be determined based on the rotational speed of a fan in the blower system, particularly the airflow blower system.

[0021] Accelerating the exhaust airflow regularly requires superimposing at least a portion of the accelerated airflow with the exhaust airflow, so that the volume flow of the exhaust airflow is increased by the accelerated airflow.

[0022] The acceleration of the exhaust airflow mentioned above can also be illustrated using the Venturi principle. The acceleration and the resulting volume flow of the airflow create a negative pressure, which in turn accelerates the exhaust airflow.

[0023] The acceleration of the exhaust airflow can be easily verified by switching off the airflow blower system, so that the airflow is no longer accelerated and thus there is no acceleration of the exhaust airflow by the accelerated airflow.

[0024] In addition to accelerating the exhaust airflow, it is also advantageous that the exhaust airflow and the accelerated airflow mix, which dilutes the exhaust airflow and thus further reduces exposure to grease, dirt and odors.

[0025] The superposition of the accelerated airflow with the exhaust airflow can be influenced by the arrangement of an airflow outlet relative to the exhaust airflow outlet. Furthermore, the design of the airflow outlet and exhaust airflow outlet, their relative arrangement, and the volume flow rates of both the airflow and exhaust airflow can affect the acceleration of the exhaust airflow by the accelerated airflow. It may be necessary to position the exhaust air outlet and the airflow outlet, particularly in close proximity to each other. Specifically, the distance between the exhaust air outlet and the airflow outlet must not be so great that the accelerated airflow prevents the exhaust airflow from accelerating.

[0026] It may therefore also be provided that the alignment of the accelerated airflow, its volume flow, the arrangement of the airflow outlet to the exhaust airflow outlet, and the design of the airflow outlet are coordinated in such a way that the exhaust airflow is accelerated by the accelerated airflow.

[0027] The airflow blower system draws in air, for example from the surroundings, and accelerates it. In other words, the airflow blower system increases the volume flow of the airflow in its direction of flow.

[0028] The airflow inlet and outlet can be connected by a simple airflow duct. Typically, the airflow fan system is also located within this duct and can therefore be positioned within the duct. In the simplest and most cost-effective case, the airflow consists of normal ambient air. This ambient air can enter the building through the airflow inlet from either outside or inside the building. Preferably, the airflow contains so few fragrances that the odor thresholds of the respective fragrances are not exceeded.

[0029] It is preferred if the exhaust air stream is extracted from an interior space, particularly a cooking area. This can be achieved, for example, via a range hood or extractor fan and a corresponding exhaust air inlet. The exhaust air stream is preferably drawn in via an exhaust air inlet, which is preferably connected to an extractor fan or range hood.

[0030] The exhaust air outlet and / or the airflow outlet preferably opens directly into the surroundings. The surroundings are defined as a space outside the area from which the exhaust airflow is extracted, particularly an area outside the building.

[0031] It is preferably provided that the exhaust air stream is accelerated upstream of the exhaust air outlet by an exhaust air blower system. Accelerating the exhaust air stream upstream of the exhaust air outlet increases its volume flow rate, which assists in conveying the exhaust air stream away from the emission source, in particular the exhaust air outlet.

[0032] Furthermore, the acceleration of the airflow can be regulated relative to the acceleration of the exhaust airflow, preferably by adjusting the airflow acceleration accordingly when the exhaust airflow acceleration changes. In other words, the airflow acceleration is increased or decreased when the exhaust airflow acceleration is increased or decreased.

[0033] In a preferred embodiment, the volume flow rate of the accelerated airflow is greater than the volume flow rate of the exhaust airflow at the exhaust air outlet. This allows for a high acceleration of the exhaust airflow and thus a stronger conveyance away from the emission source.

[0034] In a further preferred embodiment of the method, the accelerated airflow is guided parallel to the exhaust airflow and / or directed towards the exhaust airflow and / or arranged in a spiral shape around the exhaust airflow.

[0035] If the accelerated airflow and the exhaust airflow are guided parallel to each other, particularly efficient acceleration of the exhaust airflow can be achieved, since the volume flows of the accelerated airflow and the exhaust airflow have the same flow direction. Parallel guidance of the flows means that their average flow direction differs from each other by less than 10°, and in particular by less than 5°.

[0036] When the accelerated airflow is directed towards the exhaust airflow, the average flow directions of the exhaust airflow and the accelerated airflow intersect downstream of the exhaust air outlet. This leads to a strong mixing of both flows, resulting in a particularly high dilution of the exhaust airflow and thus a significant reduction in the concentration of grease, dirt, and odor components.

[0037] If the accelerated airflow is spirally directed around the exhaust air stream, a high degree of shielding of the exhaust air stream from the surrounding environment can be achieved. Therefore, the distribution of grease, dirt, and odor components into the environment only occurs in an area where they are no longer perceptible.

[0038] According to the invention, the ambient pressure is measured via a pressure gauge, in particular a manometer, and / or the wind speed via an anemometer, and the acceleration of the airflow or the power of the airflow blower system is controlled as a function of the ambient pressure and / or the wind speed. This has the advantage that the acceleration of the airflow, and thus indirectly the acceleration of the exhaust airflow, can be adapted to the ambient conditions.

[0039] Ambient pressure is the hydrostatic pressure of the air at the pressure sensor and therefore decreases compared to the pressure at sea level the higher the environment is in which the method according to the invention is to be applied.

[0040] Following this line of thought, it is preferably intended that, at a measured ambient pressure of more than 1.0 bar, the performance of the airflow blower system is set to 80% to 100% of the maximum performance (P).MAX ) to regulate. At such ambient pressures, a high acceleration of the exhaust airflow is regularly required, as otherwise the high ambient pressure promotes a sinking of the exhaust airflow or the grease, dirt and odor components, so that disturbance of the environment cannot be reliably ruled out.

[0041] In addition or as an alternative, at a measured ambient pressure of less than 1.0 bar, the performance of the airflow blower system can be reduced to 0 to less than 80% of the maximum performance (P). MAX ) can be regulated. In this case, the acceleration of the exhaust airflow can therefore be lower, since the low ambient pressure does not promote the settling of the exhaust airflow or the grease, dirt and odor components, so that a lower acceleration is usually sufficient.

[0042] It is preferred that, at a measured wind speed of 0.0 to 0.2 m / s, the power of the airflow blower system is set to at least 80% to 100% of its maximum power (P). MAX ) to regulate. In this case, the exhaust airflow is hardly affected by the low wind speeds, which is why a higher acceleration of the exhaust airflow allows for optimal routing away from the emission source.

[0043] In addition or as an alternative, at a measured wind speed of 0.3 to 5.4 m / s, the power of the airflow blower system can be reduced to less than 80% to a maximum of 40% of the maximum power (P). MAX ) be regulated and / or that at a measured wind speed of 5.5 to 13.8 m / s the power of the airflow blower system is reduced to less than 40% of the maximum power (P MAX) can be regulated. At such high wind speeds, the exhaust airflow is already sufficiently diluted and carried away from the emission source, which is why the power of the airflow blower system can be reduced for energy efficiency reasons.

[0044] For high measured wind speeds of more than 13.8 m / s, the airflow blower system can be switched off, since at such high wind speeds the exhaust airflow already receives a sufficiently high acceleration and dilution, so that the additional accelerated airflow is not absolutely necessary.

[0045] The invention also relates to a system with an exhaust air outlet, an airflow blower system and a control unit configured to perform the process steps described above.

[0046] The invention further relates to a computer program comprising instructions which, when the computer program is executed, cause the device described above, i.e. the system, to perform the process steps.

[0047] The computer program described above can be stored on a computer-readable medium.

[0048] The invention is explained in more detail below with reference to an exemplary embodiment and the drawings. All features described and / or illustrated constitute the subject matter of the invention in themselves, irrespective of their compilation in the claims or their cross-references.

[0049] They show schematically: Fig. 1: a system for a kitchen area, Fig. 2: an illustration of air movements under high pressure, Fig. 3: an illustration of air movements during low pressure, Fig. 4: an exhaust air outlet and an air outlet designed as an annular gap with parallel flow direction of exhaust air stream and air stream, Fig. 5: an exhaust air outlet and an air outlet designed as a nozzle ring with parallel flow direction of exhaust air stream and air stream, Fig. 6: an exhaust air outlet and an air outlet designed as a nozzle ring with a spiral flow direction of the airflow, Fig. 7: an exhaust air outlet and an air outlet designed as a nozzle ring with an airflow directed towards the exhaust airflow, and Fig. 8: the flow behavior of an exhaust air stream accelerated by an accelerated air stream as it exits an exhaust air stream outlet.

[0050] In Fig. Figure 1 shows a system 1 for ventilating an interior space 2. System 1 includes an exhaust air inlet 3 through which an exhaust air stream 4, originating above a cooking area 5, can enter system 1. The exhaust air inlet 3 can be located in a known extractor hood 3a. The exhaust air stream 4 is extracted from the interior space 2 and accelerated by the exhaust air fan system 6. The exhaust air stream 4 passes through the exhaust air duct 7 to an exhaust air outlet 8 and is released into the environment outside system 1 and the interior space 2.

[0051] System 1 comprises an airflow inlet 9 through which an airflow 10 enters. The airflow blower system 11 accelerates the airflow 10 along the airflow duct 13 towards an airflow outlet 12.

[0052] System 1 further comprises a control unit 14, which is configured to execute the process steps described above. In particular, the control unit 14 is designed to control the airflow and exhaust air blower systems 11 and 6 and to regulate their performance. This preferably occurs in response to signals received from the detectors 15, which are output to the control unit 14 via the signal lines 16. The detectors 15 are, in particular, non-contact flow meters that measure the volume flow of the exhaust air stream 4 and / or the air stream 10 in the respective lines 7 and 13, as well as downstream of the exhaust air stream outlet 8.

[0053] System 1 also includes a weather station 17 with a pressure gauge and an anemometer, which are configured to measure the ambient pressure and wind speed, respectively. The signals generated by the weather station 17 can be output to the control unit 14, so that the ambient pressure and / or wind speed can be used to control and regulate the performance of the airflow and / or exhaust fan system 11 and 6.

[0054] Fig. Figure 2 schematically shows the air movement at an ambient pressure of more than 1.0 bar. At such ambient pressures, a vertical sinking of the ambient air regularly occurs, which can place a corresponding load on an exhaust airflow, making it perceived as particularly disturbing in the vicinity of an emission source. In this case, it is preferable to maximize the acceleration of the airflow and thus indirectly that of the exhaust airflow. The control unit 14 can achieve this by evaluating the signals from the weather station 17 and correspondingly controlling the airflow and / or exhaust air blower systems 11 and 6.

[0055] Fig. Figure 3 schematically shows the air movement at an ambient pressure of less than 1.0 bar. At such ambient pressures, a vertical rise of the ambient air regularly occurs, which promotes the removal of the exhaust air stream from the emission source. In this case, it is preferred if the acceleration of the air stream, and thus indirectly that of the exhaust air stream, is reduced so that the method according to the invention is carried out energy-efficiently.

[0056] Fig. Figure 4 schematically shows an exhaust air outlet 8 and an air outlet 12 designed as an annular gap 18, which is arranged concentrically to the exhaust air outlet 8. The in Fig. The four block arrows shown indicate the flow direction of the exhaust air stream 4 and the air stream 10. The flow direction of the air stream 10 is indicated by several block arrows, even though a hollow cylindrical flow profile is actually obtained for the air stream 10. In the case shown here, the flow directions of exhaust air stream 4 and air stream 10 are parallel. The distance 19 between the exhaust air stream outlet 8 and the air stream outlet 12, which is designed as an annular gap 18, must be selected such that the air stream 10 can accelerate the exhaust air stream 4 at a given volume flow rate.

[0057] In Fig. 5 is a nozzle ring 20 designed as an airflow outlet 12, wherein the individual nozzles 21 are arranged evenly on a circular path around the exhaust airflow outlet 8. As in Fig. 2 the flow direction of the airflow 10 and the exhaust airflow 4 is provided to be essentially parallel to each other.

[0058] Fig. Figure 6 shows the same arrangement of exhaust air outlet 8 and air outlet 12 or nozzle ring 20 as Fig. 5, however, the orientation of the nozzles 21 has been changed so that a spiral airflow 10 is formed, which is indicated by the change in the direction of flow of the airflow 10 leaving the nozzles 21.

[0059] Fig. Figure 7 shows the arrangement of exhaust air outlet 8 and air outlet 12 or nozzle ring 20 as shown in the Fig. 5 and Fig. 6, however, the orientation of the nozzles 21 is changed so that the airflow 10 exiting the nozzles 21 is directed towards the exhaust airflow 4 and meets the exhaust airflow 4 in a conical arrangement downstream of the exhaust airflow outlet 8.

[0060] Fig. Figure 8 illustrates a variant of the flow behavior of an exhaust air stream 4, which enters the exhaust air ducts 7 at the exhaust air inlet 3, exits at the exhaust air outlet 8, and is subsequently accelerated by an accelerated air stream 10. In this case, the air stream 10 is discharged via the air outlet 12 and is directed towards the exhaust air stream 4. Due to the acceleration by the air stream 10, additional mixing air is drawn in at an external mixing air intake area 22, and the exhaust air stream 4 is shielded from the outside by the air stream 10. Furthermore, the exhaust air stream 4 is accelerated to such an extent that the exhaust air is only distributed in an area that is no longer perceptible to the surroundings.

[0061] In this case, the velocity of the airflow 10 is reduced by the intake of the mixed air, resulting in a lower acceleration of the exhaust airflow 4. At the same time, however, there is an additional dilution, thus reducing the odor nuisance from the exhaust airflow 10 in the mixed air intake area 22.

[0062] The following table gives an example of how to regulate the power of the fan in the airflow blower system (P). ventilator ) relative to the maximum power of the fan (P MAX ) of the airflow blower system, with the power depending on the wind speed (v Wind ) and / or the ambient pressure (pu). Table 1: Fan (PVentilator) power relative to the maximum fan power (PMAX) of the airflow blower system P ventilator [%] V Wind [m / s] | Windstärkte[Beaufort-Skala] p U [hPa] 100 0,0 - 0,2 0 > 1013,25 80 0,0 - 0,2 0 = 1013,25 79 - 40 0,3 - 5,4 1-3 < 1013,25 39 - 1 5,5 - 13,8 4-6 0 13,9 - 36,9 7 - 12 Reference sign 1 system 2 Interior 3 Exhaust air flow inlet 3a Vapor extraction 4 Exhaust air flow 5 Cooking area 6 Exhaust fan system 7 Exhaust air flow duct 8 Exhaust air outlet 9 Airflow inlet 10 Airflow 11 Airflow blower system 12 Airflow outlet 13 Airflow duct 14 Control unit 15 Detector 16 Signal line 17 weather stations 18 annular gap 19 gap 20 nozzle rings 21 nozzles 22 Mixing air intake area

Claims

[1] Method for accelerating and diluting an exhaust air stream (4), comprising: - Accelerating an airflow (10) with an airflow blower system (11), - Aligning the accelerated airflow (10) with an exhaust airflow (4) exiting from an exhaust air outlet (8) such that a - Acceleration and dilution of the exhaust air stream (4) downstream of the exhaust air stream outlet (8) is carried out by the accelerated air stream (10), characterized by , that an ambient pressure and / or wind speed is detected and that the power of the airflow blower system (11) is controlled depending on the ambient pressure and / or wind speed. [2] Method according to claim 1, characterized by , that the exhaust air stream (4) is extracted from an interior space (2), in particular a cooking area (5) and / or that the exhaust air stream (4) is released into the environment. [3] Method according to one of the preceding claims, wherein the exhaust air flow (4) is accelerated upstream of the exhaust air flow outlet (8), characterized by , that the acceleration of the airflow (10) is regulated to the acceleration of the exhaust airflow (4). [4] Method according to any one of the preceding claims, characterized by , that the volume flow of the accelerated airflow (10) is greater than the volume flow of the exhaust airflow (4) at the exhaust airflow outlet (8). [5] Method according to any one of the preceding claims, characterized by , that the accelerated airflow (10) is directed parallel to the exhaust airflow (4) and / or towards the exhaust airflow (4) and / or spirally around the exhaust airflow (4). [6] Method according to any one of the preceding claims, characterized by , that at a measured ambient pressure of more than 1.0 bar, the performance of the airflow blower system (11) increases to 80% to 100% of the maximum power (P MAX) is regulated, and / or that at a measured ambient pressure of less than 1.0 bar, the power of the airflow blower system (11) is reduced to 0 to less than 80% of the maximum power (P MAX ) is regulated. [7] Method according to any one of claims 1 to 5, characterized by , that at a measured wind speed (v wind ) from 0.0 to 0.2 m / s the power of the airflow blower system (11) to at least 80% to 100% of the maximum power (P MAX ) is regulated, and / or that at a measured wind speed (v wind ) from 0.3 to 5.4 m / s the power of the airflow blower system (11) to less than 80% to a maximum of 40% of the maximum power (P MAX ) is regulated, and / or that at a measured wind speed (v wind ) from 5.5 to 13.8 m / s the power of the airflow blower system (11) to less than 40% of the maximum power (P MAX ) is regulated. [8] System (1) comprising an exhaust air outlet (8), an airflow blower system (11) and a control unit (14) configured to perform the process steps according to any of the preceding claims. [9] System (1) according to claim 8, characterized by , that in the execution of the process steps by the control unit (14) a computer program comprising instructions which, when the computer program is executed, effect the process steps is used.

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