NL2026245B1

NL2026245B1 - Air treatment system

Info

Publication number: NL2026245B1
Application number: NL2026245A
Authority: NL
Inventors: Van Der Aa Adrianus
Original assignee: Quake B V
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2022-04-13
Also published as: WO2022035315A1

Abstract

An air treatment system for the treatment of air contained in a room, the room comprising a wall, a ceiling and a floor; an inner volume of the room comprising two vertically spaced apart imaginary zones that each span the entire cross-sectional area of said inner volume, the first zone being arranged at a height that corresponds to a breathing height of persons in said room, the second zone being arranged below the first zone, wherein the air treatment system comprises a plurality of air outlets that are associated with the ceiling of the room, each air outlet being configured to blow air into the room in a downward direction, wherein the plurality of air outlets are positioned in the ceiling to provide a laminar downflow of air in substantially the entire first zone, to push air present in the first zone downwards into the second zone.

Description

Title: Air treatment system

BACKGROUND OF THE INVENTION The present invention relates to an air treatment system for treating airin a room, a room comprising such an air treatment system, a method for upgrading the air treatment system of a room and a method for treating the air in a room.

In times of an epidemic or pandemic, social distancing rules may be implemented by governments to minimize the risk of airborne virus transmissions between people. Depending on the jurisdiction the exact required distance may vary, but usually the rules prescribe a distance of between 1m and 2 m (i.e. about 3 ft — 7 ft). Such a distance is commonly accepted as a safe distance to prevent virus transmission from one human being to another human being. Especially indoors, social distancing is important in times of a pandemic or epidemic. This leads to all sorts of problems related to crowd management in small and busy indoor rooms, e.g. rooms where there is a relatively large “traffic” of human persons. For example in elevators, the number of passengers allowed is drastically reduced when social distancing measures are implemented, which leads to huge problems and ques in high residential buildings and offices. The same problem is conceived around toilet blocks in offices, narrow hallways, and vehicle interiors, e.g. in public transportation. The currently applied ventilation principles and systems applied in these indoor rooms are not adequate to prevent airborne transmissions of viruses between passengers without a distance of less than 1 meter between persons and thus the number of persons cannot be increased without increasing the risk of virus transmissions between persons in such rooms.

For example lift cabins are typically equipped with a cabin ventilation in accordance with the NEN EN 81-20, NEN EN 81-50, NEN EN 81-1 and NEN EN 81-

2. The currently applied ventilation in lift cabins is based on a mixing ventilation principle that controls the density of indoor pollutants using the dilution principle, by bringing in a sufficient amount of fresh air to dilute emissions from indoor sources uniformly. The capacity of the ventilation air is chosen with the focus on maintaining an adequate air quality in the passenger lift cabin. The location of supply and exhaust provisions is of minor importance as long as sufficient fresh air is supplied and extracted in relation to the required indoor air quality in the lift cabin.

Solutions to shield the air in one part of a room with respect to another part of the room have been proposed in the form of so-called air curtains. An air curtain is a stream of air from the ceiling to the floor of the room, which act as a barrier for any air (including airborne viruses) to move from one side of the room to another side of the room. While such air curtains would be able to increase the capacity of small and crowded rooms somewhat, it is deemed an insufficient solution in times of an epidemic or pandemic. For example, when using an air curtain to shield two parts of a room, one would not be able to walk across the room. One has to stay inside ones bubble, as soon as ones steps out of ones bubble through an air curtain, the risk of infections arise again. Furthermore, although one can indicate where people can stand in rooms controlled by air curtains, there is no guarantee that people will actually comply and only stand in the designated places, again increasing the risk of virus transmission. Therefore, it would be desirable to have an air treatment system for a room that allows several people to be in the room and move across the room, without the risk of viral transmissions through the air and while minimizing the social distancing required between persons.

SUMMARY OF THE INVENTION Therefore, according to a first aspect of the present disclosure, an air treatment system is provided for the treatment of air contained in a room, wherein the room comprises at least one wall, a ceiling and a floor; an inner volume of the room comprising at least two imaginary zones that are vertically spaced apart from each other and each span the entire cross-sectional area of said inner volume, wherein the first zone is arranged at a height that corresponds to a breathing height of persons in said room and wherein the second zone is arranged below the first zone, wherein the air treatment system comprises a plurality of air outlets that are associated with the ceiling of the room, each air outlet being configured to blow air into the room in a downward direction, wherein the plurality of air outlets are positioned in or below the ceiling to provide a laminar downflow of air in substantially the entire first zone, to push air present in the first zone downwards into the second zone.

Advantageously, as the plurality of air outlets provide a laminar downflow of air in substantially the entire first zone, air exhaled by persons in the room is directly transported downwards towards the second zone. If the exhaled air of a first person in the room contains any contagious viruses, the air is directly transported outside the breathing zone such that it cannot be inhaled by another person in the room, even when that other person stands close to, e.g. closer than 1 meter such as within 30 cm — 50 cm or even closer to the first person. The laminar downflow of air ensures that the air in the breathing zone of the room is always fresh, i.e. free of potentially contagious viruses. This thus allows people in the room to stand relatively close together instead of at a distance of 1 — 2 m from each other. This drastically increases the capacity of the room, while still ensuring that the risk of airborne viral transmissions between people in the room is minimized.

Further advantageously, as the laminar downflow of air is present in substantially the entire first zone, people can safely walk from one side of the room to the other side of the room without passing barriers and walking through differently controlled parts of the room. At least in the zone that is arranged at a height corresponding to a breathing height of persons in the room, air conditions are safe and uniform in the entire room.

Further advantageously, the air treatment system can provide a safe environment to everyone in the room, irrespective of the location of contagious persons. This is highly desirable, as it is typically not known in times of an epidemic or pandemic who is infected and contagious and who is not, so a dedicated position for potentially infected persons would not be of any help, as all persons in the room are potentially infected.

In accordance with the present disclosure, for the purpose of describing the working of the air treatment system, the inner volume of the room is divided in at least two imaginary zones, each spanning a certain height level. A first zone corresponds to a height in which persons in the zone breath, i.e. a height in which people inhale air and exhale air. A second zone corresponds to a height level below the first zone. Possibly a third zone may be arranged above the first zone.

In accordance with the present disclosure, for the purpose of describing the working of the air treatment system, the room comprises an inner volume. The inner volume is defined herein as the volume defined by the walls of the room and in between the ceiling and the floor. When the walls of the room are double-

walled, the inner volume is defined between the inner walls of the room and in between the ceiling and the floor. When the ceiling or floor of the room does not correspond to a structural ceiling or floor of the room, the inner volume is defined between the cosmetic ceiling and floor.

In accordance with the present disclosure, for the purpose of describing the working of the air treatment system, the first and second zone are height zones, spanning the entire cross-sectional area of the room at that height level, so that the same conditions apply in substantially the entire cross-sectional area of the room, at the same height level.

In accordance with the present disclosure, the air treatment system comprises a plurality of air outlets that are associated with the ceiling. For example the air outlets may be mounted in the structural or cosmetic ceiling, the ceiling e.g. being perforated to allow air to come out of the ceiling. In another example, the air outlets may be mounted below the structural or cosmetic ceiling, free to blow air in the room in a downward direction.

In accordance with the present disclosure, the air treatment system comprises a plurality of air outlets. For example, the air outlets may be arranged in the ceiling in concentric circles. For example, the air outlets may be arranged in the ceiling in parallel rows. For example, a so-called diffuser ceiling or diffuser plate may be used to effect a laminair downflow of air in the first zone. Alternatively any other type of air outlet system, e.g. one known in the art, may be used in accordance with the present invention to achieve a laminar downflow of air in the first zone. For example, in a zone directly below the ceiling the air may be turbulent, the air reaching the laminar flow state only after having travelled a vertical distance in the room. The ceiling is installed at the required height to ensure that in the zone corresponding to a breathing height of persons in the room the air is in a laminar downflow state.

In accordance with the present invention, the air outlets are positioned in the ceiling to provide a laminar downflow of air. A laminar downflow of air might also be known as a so-called plug flow or under the term displacement ventilation. The laminar downflow in the first zone pushes the air in the first zone downwards, into the second zone in a way similar to how a plunger of an engine pushes the air in a piston downwards. Preferably the room also comprises an air outlet, leaving out as much air per second as is introduced by the air outlets, such that the air in the room is not compressed but continuously refreshed (unlike the air in a piston).

It will be understood that even though the flow is described as laminar, the speed of the air may locally differ by approximately + 0.1 m/s from the average downwards flow rate and a completely uniform flow field may not be obtained. The flow is however preferably always oriented downwards throughout substantially the entire first zone. 5 In accordance with the present invention, air may be mixed in the second zone. However in the first zone the air flows in a downwards direction and is laminar, transporting any contagious viruses exhaled by persons in the room also downwards and outside of the breathing zone so that the viruses may not be inhaled by other persons in the same room, even though persons stand closer to each other than the accepted social distancing distance of 1 — 2 m.

In accordance with the present invention, the laminar downflow of air is provided in substantially the entire first zone. It will be understood that close to the inner walls of the room, e.g. within a distance of 0 — 15 cm from the walls, the downflow may be less optimally controlled due to interference of flow with the wall.

In an embodiment according to the first aspect of the present disclosure, a downwards flow rate of the air in the first zone is between 0.05 and 1 m/s, preferably between 0.1 m/s and 0.6 m/s, more preferably between 0.2 m/s and

0.4 m/s.

Advantageously, this flow rate is sufficiently high to transport any airborne viruses exhaled by a contagious person in the room downwards and outside of the breathing zone before it can be inhaled by another person standing within e.g. less than one meter such as within 0.3 — 0.5 m of the contagious person. Advantageously, at the same time, such a downflow rate may not be perceived as inconvenient by persons in the room.

In an embodiment according to the first aspect of the present disclosure, the air treatment system comprises a sensor for monitoring the presence of persons in the room as well as a controller for controlling the air outlets, the sensor and the air outlets each being arranged in communication with the controller, and the controller being configured for continuously operating the air treatment system when the sensor detects the presence of persons in the room.

Advantageously, the air treatment system is operated continuously when at least one person is inside the room. To save energy, the air treatment system may be shut off when no persons are in the room. For example, the air treatment system may be operated for another 5 to 30 seconds after the last person has left the room to provide the room with fresh and clean air and afterwards it may be shut off.

In an embodiment according to the first aspect of the present disclosure, the air treatment system further comprises an air inlet arranged in fluid communication with the plurality of air outlets and a filter system arranged in between the air inlet and the plurality of air outlets, the filter system comprising an air purification unit. One example of such an air purification unit is a UV-C lighting unit, but other types or air purification units are also known and/or may be found after the filing date of the present disclosure.

It is of crucial importance that the air blown into the room through the air outlets is clean air, not containing contagious viruses. Therefore, preferably in between the air inlet of the air treatment system and the air outlets thereof, the air is cleaned and any such viruses are removed or killed. This may e.g. be effected with one or more UV-C lighting units.

In an embodiment according to the first aspect of the present disclosure, the UV-C lighting unit is arranged outside the inner volume of the room.

Advantageously, this will prevent human persons to come into contact with dangerous UV-C lighting.

In an embodiment according to the first aspect of the present disclosure, the UV-C lighting unit is arranged inside the inner volume of the room.

Preferably, the UV-C lighting is then shielded by a container which prevents the UV-C lighting from radiating human persons.

In an embodiment according to the first aspect of the present disclosure, the height of the first zone is between approximately 1.4 m and approximately 2 m from the floor. This corresponds to a breathing height when people in the room are standing.

In an embodiment according to the first aspect of the present disclosure, the height of the first zone is between approximately 0.8 m and approximately 1.4 m from the floor. This corresponds to a breathing height when people in the room are sitting on chairs.

A second aspect of the present disclosure relates to a room comprising the air treatment system as described in the above.

Advantages obtained with the room according to the second aspect of the disclosure are similar to advantages obtained with the air treatment system according to the first aspect of the disclosure.

Embodiments described in the above in relation to the first aspect of the disclosure are also advantageous in a room according to the second aspect of the disclosure.

In an embodiment according to the second aspect of the present disclosure, the surface area of the room is less than 20 m2.

Advantageously, the smaller the room the more easy it may be to ensure that the flow in the first zone is laminar throughout the entire zone.

In an embodiment according to the second aspect of the present disclosure, the room is an elevator cabin, a toilet, a hallway, a traffic room, a waiting room or a vehicle interior.

Advantageously, it is especially these kinds of rooms where capacity is severely limited when social distancing rules are imposed and which have a large impact on crowd control in buildings and public infrastructure. When the flow of people in these rooms can be improved, this has a huge impact in making social distancing rules better accepted by the population.

Traffic rooms are, within the context of the present disclosure, defined as rooms which see a relatively high traffic of human persons. Examples are hallways leading towards toilet blocks in offices, entrances of buildings, waiting rooms before elevators, coffee corners in offices, etc. etc.

In an embodiment according to the second aspect of the present disclosure, the room comprises at least one wall that is at least partially double-walled room and has an inner wall, an outer wall spaced apart from the inner wall and a flow channel in between the inner wall and the outer wall, wherein during operation of the air treatment system the air in the flow channel flows in a direction apposite to the air in said first zone.

Advantageously, when the room in which the air treatment system is used is not suited to also allow the controlled removal of the same amount of air as which is blown into the room by the air outlets of the air treatment system, the installation of temporary inner walls with an flow channel between the inner walls and the outer walls may ensure that the air treatment system works properly and a balance of air in the room is contained. For example, all walls of the room may be double-walled, or only one wall may be double-walled, or one wall may be partially double-walled, including an embodiment wherein one or more corners of the room are double-walled.

A third aspect of the present disclosure relates to a method for upgrading the air treatment system of a room, the method comprising at least the step of installing a plurality of air outlets in or near the ceiling, the plurality of air outlets being positioned in or near the ceiling to provide a laminar downflow of air in a zone of the room that corresponds to a breathing height of persons in said room.

Advantageously, using this method one may modify and upgrade an existing room to make it “pandemic-proof” without needing to completely remodel the room and obtain similar advantages as those described in relation to the first aspect of the present disclosure.

Of course, it is also possible to use the air treatment system as presented herein in a newly built room.

In an embodiment according to the third aspect of the present disclosure, the method further comprises the step of installing an inner wall in front of and at a distance from the outer wall of the room, so that a flow channel is defined in between the inner wall and the outer wall, the inner wall reaching at least from the ceiling to the lower limit of said zone, wherein preferably an opening is arranged between the floor of the room and the inner wall of the room, to allow air to flow to the flow channel from the inner volume of the room defined by the inner wall. For example, the opening may be unobstructed. For example, a roster, a membrane, or any other physical structure may cover the opening.

Advantageously, when the room in which the air treatment system is used is not suited to also allow the controlled removal of the same amount of air as which is blown into the room by the air outlets of the air treatment system, the installation of temporary inner walls with an flow channel between the inner walls and the outer walls may ensure that the air treatment system works properly and a balance of air inside the room is contained.

A fourth aspect of the present disclosure relates to a method for treating the air in a room, wherein use is made of the air treatment system according to the first aspect of the present disclosure.

These above-mentioned and other features and advantages of the disclosure will be best understood from the following description referring to the attached drawings. In these drawings, like reference numerals denote identical parts or parts with an identical or similar function or operation.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates, in a cross-sectional view, a first embodiment of a room equipped with an air treatment system according to the present invention; Figure 2 schematically illustrates, in a top view, the ceiling of Figure 1; Figure 3 schematically illustrates, in a cross-sectional view, a second embodiment of a room equipped with an air treatment system according to the present invention; Figure 4 schematically illustrates, in a top view, the ceiling of Figure 3; Figure 5 schematically illustrates, in a cross-sectional view, a third embodiment of a room equipped with an air treatment system according to the present invention; and Figure 6 schematically illustrates, in a top view, the ceiling of Figure 5.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to Figure 1, an air treatment system 1 is shown installed in an elevator cabin 100, for treatment of the air in the elevator cabin 100. The elevator cabin 100 is shown in a cross-sectional view along a vertically oriented plane, such that two walls 101, 102 of the elevator cabin 100 are shown as well as a structural ceiling 103A, a cosmetic ceiling 103B and a floor 104. An inner volume of the elevator cabin 100 is defined between the walls 101, 102, the cosmetic ceiling 103B and the floor 104. The inner volume comprises a first imaginary zone Z1 and a second imaginary zone Z2, the two zones Z1, Z2 being spaced apart from each other when seen in the vertical direction. That is, the two zones Z1, Z2 are arranged above one another.

The zones Z1, Z2 each span only a part of the elevator cabin 100 when seen in the vertical direction and span the entire cross-sectional area of the elevator cabin 100 when seen in a horizontal direction.

The first zone Z1 is arranged at a height that corresponds to a breathing height of persons in the elevator cabin 100. Although the elevator cabin 100 is here shown without any persons in it, one will understand that when the elevator cabin 100 goes up and down in the elevator shaft 200, it may have persons in it. Persons will typically stand in the elevator cabin 100.

Accordingly, the first zone Z1 is arranged at a height of about 1.4 m to approximately 2 m above the floor. In non-shown embodiments, e.g. when the room is not an elevator cabin 100 but e.g. the interior or a train or a train compartment, persons may be seated and the first zone Z1 may be arranged at a height of about 0.8 m to about 1.4 m above the floor.

As shown, and better visible in Figure 2, the ceiling 103B of the elevator cabin 100 comprises a number of perforations, through which air outlets 11 blow air into the interior volume of the elevator cabin 100, in a downward direction as indicated by arrows in Figure 1, towards the floor 104. In the cross-sectional view shown in figure 1 only one row of air outlets 11 is shown, but one understands from the top view of figure 2 that the entire ceiling 103 comprises such perforations The exact geometry of the air outlets 11 may vary in different embodiments. In certain cases they may be arranged in concentric circles whereas in other cases they may be arranged in parallel rows, as shown in figure 2.

Each of the air outlets 11 is configured to blow air in a downwards direction into the elevator cabin 100, so that the plurality of air outlets 11 together provide a laminar downflow in substantially the entire first zone Z1.For example, the flow speed of air in the downwards direction, in the first zone Z1, may roughly be between 0.05 and 1 m/s, such as between 0.1 m/s and 0.6 m/s, preferably in between 0.2 m/s and 0.4 m/s. In that way, air at the breathing height of persons in the elevator cabin 100 is constantly refreshed with clean air and contagious viruses cannot be spread when several persons are in the room even when they stand closer to each other than about 1.5 m from each other.

Further visible in Figure 1 is a sensor 12 mounted on the wall 101 of the elevator cabin at the height level of the first zone Z1. The monitor is configured for monitoring the presence of persons in the elevator cabin 100. Further visible in Figure 1 is a controller 13 for controlling an operational state of the air treatment system 1. The sensor 12 and the air outlets 11 are each arranged in communication with the controller 13, and the controller 13 is configured for continuously operating the air treatment system 1 when the sensor 12 detects the presence of persons in the cabin 100.

Further visible in Figure 1 is an air inlet 14 although, as follows from figure 2, there may be several air inlets 14, arranged in fluid communication with the plurality of air outlets 11. The air inlets 14 draws air from the elevator shaft 200. Before being passed to the air outlets 11, the air taken in by the air inlets 14 passes through a filter system 15 that is arranged in between the air inlets 14 and the plurality of air outlets

11. To kill any potentially contagious viruses, the filter system 15 comprising one or more UV-C lighting unit 151. Advantageously, the UV-C lighting units 151 are arranged outside the interior volume of the elevator cabin 100, as exposure of humans to UV-C light is dangerous. Alternatively, when the UV-C lighting units 151 are arranged inside the interior volume of the elevator cabin 100, they are preferably shielded by a container which is impenetrable for the UV-C lighting. In the example of Figure 1, air leaves the cabin though vents in the walls 101,

102. The total flow rate of air leaving the cabin 100 will be approximately equal to the total flow rate of air blown into the cabin 100 by the air outlets 11. Turning now to Figure 3, the air treatment system shown in this figure comprises the same components as the air treatment system of Figure 1. In addition, the walls 101A, 101B, 102A, 102B of the elevator cabin 100 are double-walled. That is, the elevator cabin 100 has an inner wall 101A, 102A and an outer wall 101B, 102B spaced apart from the inner wall 101A, 102A. Inner walls 101A, 102A extend downwards from the structural ceiling 103A, through the first zone Z1 and into the second zone Z2. Opening 106 is defined between the bottom face of inner walls 101A, 102A and the floor 104. A flow channel 105 is defined in between the inner walls 101A, 102A and the outer walls 101B, 102B. During operation of the air treatment system 1 the air in the flow channel 105 flows in a direction opposite to the air in said first zone Z1 and circles back towards the air inlet 14, so that a circular air treatment system 1 is obtained wherein the same air is circulated all the time. Of course, before being re- injected in the elevator cabin 100, the air previously injected in the elevator cabin 100, having passed through the first zone Z1 and the flow channel 105 must first be cleaned by filter system 14 before being injected into the inner volume of the elevator cabin 100 again. Turning now to Figure 5, the air treatment system shown in this figure comprises the same components as the air treatment system of Figure 1. Comparing Figure 5 to Figure 3, is may be observed that Figure 5 comprises a flow duct through which the air flows as it leaves the inner volume of the room 100 instead of the double-walled solution of Figure 3. Although not shown, active suction may be applied, e.g. by a pump of some sorts, to remove the air from the inner volume of the room 100 through air duct 105. For example, the air duct 105 may be arranged in corners of the room

100. Advantageously, when the air leaves the room 100 near the ceiling 103B instead of near the floor 104 as in the embodiment of Figure 1, and when the room 100 is an elevator cabin 100 moving up and down in elevator shaft 200, the air pressure near the air outlet of the air duct 105 is similar to the air pressure of the air entering the air inlet 14 of the air treatment system 1. It is further noted that the air treatment system 1 of Figure 5 is an open-loop system. Whereas the same air is circulated all the time in the embodiment of Figure 3, in the embodiment of Figure 5 it is of course also possible that air enters the inner volume of the room 100 again after it has been used by the air treatment system 1, but it is not the same volume of air that circulates all the time.

LIST OF REFERENCE NUMERALS 1 Air treatment system 11 Air outlet 12 Sensor 13 Controller 14 Air inlet 15 Filter system 151 air purification unit, UV-C lighting unit 100 Room 101 Wall 102 Wall 103 Ceiling 104 Floor 105 Flow channel, air duct 106 opening 200 Elevator shaft | Inner volume of room Z1 First zone of room Z2 Second zone of room

Claims

CONCLUSIONS

An air conditioning system (1) for treating air in a space (100), the space (100) comprising at least a wall (101, 102), a ceiling (103) and a floor (104); wherein an inner volume (I) of the space (100) comprises at least two imaginary zones (Z1, Z2) arranged at a vertical distance from each other and each spanning the entire sectional plane of the inner volume (I), the first zone ( Z1) is arranged at a height corresponding to a breathing height of persons in said space (100) and wherein the second zone (Z2) is arranged below the first zone (Z1), wherein the air conditioning system (1) has a plurality of air outlets (11) associated with the ceiling (103) of the space (100), each air outlet (11) being arranged to blow air into the space (100) in a downward direction, the plurality of air outlets {11 ) are positioned in or below the ceiling (103) to provide a laminar downward flow of air in substantially the entire first zone (Z1), to force the air contained in the first zone (Z1) downward in the second zone ( Z2).

The air handling system according to claim 1, wherein a downward flow velocity of the air in the first zone (Z1) is between 0.05 m/s and 1 m/s, such as between 0.1 m/s and 0.6 m/s, preferably between 0.2 m/s and 0.4 m/s.

The air handling system according to claim 1 or 2, comprising a sensor (12) for monitoring the presence of persons in the room (100) and a controller (13), the sensor (12) and the air outlets (11) each are arranged in communication with the controller (13), and wherein the controller (13) is arranged for continuous operation of the air handling system (1) when the sensor (13) detects the presence of at least one person in the room (100 ) detects.

The air handling system of any preceding claim, further comprising an air inlet (14) disposed in fluid communication with the plurality of air outlets (11) and a filter system (15) disposed between the air inlet (14) and the plurality of air outlets (11) wherein the filter system (15) comprises an air purification unit, such as a UV-C light unit (151).

The air conditioning system according to claim 4, wherein the UV-C light unit (151) is arranged outside the interior volume (I) of the space (100).

The air conditioning system according to claim 4, wherein the UV-C light unit (151) is arranged within the interior volume (I) of the space (100).

The air handling system according to any of the preceding claims, wherein the height of the first zone (Z1) is between about 1.4 m and about 2 m from the floor (104) of the room (100).

The air handling system according to any one of the preceding claims, wherein the height of the first zone (Z1) is between about 0.8 m and about 1.4 m from the floor (104) of the room (100).

A room (100) comprising the air treatment system (1) according to any one of claims 1 to 8.

The space of claim 9, wherein the area of the space (100) is less than 20 m 2 .

The room according to claim 9 or 10, wherein the room (100) is an elevator car, a toilet, a hall, a waiting room, a traffic room or a vehicle interior.

The space of any one of claims 9-11, wherein the space (100) comprises at least one wall (101, 102) that is at least partially double-walled and an inner wall (101A, 102A), an outer wall (101B , 102B) arranged at a distance from the inner wall (101A, 102A) and has a flow channel (105) between the inner wall (101A, 102A) and the outer wall (101B, 102B), wherein during an operation of the air conditioning system ( 1) the air in the flow channel (105) flows in a direction opposite to the air in the first zone (Z1).

A method of upgrading the air handling system of a room (100), the method comprising at least the step of installing a plurality of air outlets (11) in or near the ceiling (103), and positioning the said air outlets (11) so as to provide a laminar downward flow of air in a zone (Z1) of the space (100) corresponding to a breathing height of persons in the space (100).

The method of claim 13, further comprising the step of installing the inner wall (101A, 102A) in front of and spaced from the outer wall (101B, 102B) of the space (100) such that a flow channel ( 105) is defined between the inner wall (101A, 102A) and the outer wall (101B, 102B), the inner wall (101A, 102A) extending from the ceiling (103) to at least the lower limit of the first zone ( Z1), preferably an opening (106) being provided between the floor (104) of the space (100) and the inner wall (101A, 102A) of the space (100), to allow air to flow to the flow channel (105) flows from the inner volume (11) defined by the inner wall (101A, 102A).

A method of treating the air in a room (100), using the air conditioning system (1) according to any one of claims 1 to 8.